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Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
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1

How Lead-Free Solder (Mis)Behaves under Stress | Advanced Photon...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

the evolution of crystal orientation and strain patterns during thermal cycling in tin-containing, lead-free solder joints, specifically in the commonly used...

2

Breakthrough: Lead-free Solder  

ScienceCinema (OSTI)

Ames Laboratory senior metallurgist Iver Anderson explains the importance of lead-free solder in taking hazardous lead out of the environment by eliminating it from discarded computers and electronics that wind up in landfills. Anderson led a team that developed a tin-silver-copper replacement for traditional lead-tin solder that has been adopted by more than 50 companies worldwide.

Anderson, Iver

2013-03-01T23:59:59.000Z

3

Breakthrough: Lead-free Solder  

SciTech Connect (OSTI)

Ames Laboratory senior metallurgist Iver Anderson explains the importance of lead-free solder in taking hazardous lead out of the environment by eliminating it from discarded computers and electronics that wind up in landfills. Anderson led a team that developed a tin-silver-copper replacement for traditional lead-tin solder that has been adopted by more than 50 companies worldwide.

Anderson, Iver

2012-01-01T23:59:59.000Z

4

Lead-Free Solder - Energy Innovation Portal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Lab Date Patent 5,527,628 Patent 5,527,628 Pb-free Sn-Ag-Cu ternary eutectic solder A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6...

5

Development of lead-free solders for hybrid microcircuits  

SciTech Connect (OSTI)

Extensive work has been conducted by industry to develop lead-free solders for electronics applications. The driving force behind this effort is pressure to ban or tax the use of lead-bearing solders. There has been further interest to reduce the use of hazardous chemical cleaners. Lead-free soldering and low-residue, ``no clean`` assembly processing are being considered as solutions to these environmental issues. Most of the work has been directed toward commercial and military printed wiring board (PWB) technology, although similar problems confront the hybrid microcircuit (HMC) industry, where the development of lead-free HMC solders is generally lagging. Sandia National Laboratories is responsible for designing a variety of critical, high reliability hybrid components for radars. Sandia has consequently initiated a project, as part of its Environmentally Conscious Manufacturing program, to develop low-residue, lead-free soldering for HMCs. This paper discusses the progress of that work.

Hosking, F.M.; Vianco, P.T.; Frear, D.R.; Robinson, D.G.

1996-01-01T23:59:59.000Z

6

Hybrid microcircuit board assembly with lead-free solders  

SciTech Connect (OSTI)

An assessment was made of the manufacturability of hybrid microcircuit test vehicles assembled using three Pb-free solder compositions 96.5Sn--3.5Ag (wt.%), 91.84Sn--3.33Ag--4.83Bi, and 86.85Sn--3.15Ag--5.0Bi--5.0Au. The test vehicle substrate was 96% alumina; the thick film conductor composition was 76Au--21Pt--3Pd. Excellent registration between the LCCC or chip capacitor packages and the thick film solder pads was observed. Reduced wetting of bare (Au-coated) LCCC castellations was eliminated by hot solder dipping the I/Os prior to assembly of the circuit card. The Pb-free solders were slightly more susceptible to void formation, but not to a degree that would significantly impact joint functionality. Microstructural damage, while noted in the Sn-Pb solder joints, was not observed in the Pb-free interconnects.

Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

2000-01-11T23:59:59.000Z

7

Assessment of circuit board surface finishes for electronic assembly with lead-free solders  

SciTech Connect (OSTI)

The suitability of various metallic printed wiring board surface finishes was assessed for new technology applications that incorporate assembly with Lead-free solders. The manufacture of a lead-free product necessitates elimination of lead (Pb) from the solder, the circuit board as well as the component lead termination. It is critical however for the selected interconnect Pb-free solder and the corresponding printed wiring board (PWB) and component lead finishes to be mutually compatible. Baseline compatibility of select Pb-free solders with Pb containing PWB surface finish and components was assessed. This was followed by examining the compatibility of the commercially available CASTIN{trademark} (SnAgCuSb) Pb-free solder with a series of PWB metallic finishes: Ni/Au, Ni/Pd, and Pd/Cu. The compatibility was assessed with respect to assembly performance, solder joint integrity and long term attachment reliability. Solder joint integrity and mechanical behavior of representative 50 mil pitch 20I/O SOICs was determined before and after thermal stress. Mechanical pull test studies demonstrated that the strength of SnAgCuSb solder interconnections is notably greater than that of SnPb interconnections.

Ray, U.; Artaki, I.; Finley, D.W.; Wenger, G.M. [Bell Labs., Princeton, NJ (United States). Lucent Technologies; Pan, T.; Blair, H.D.; Nicholson, J.M. [Ford Motor Co., Dearborn, MI (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1996-10-01T23:59:59.000Z

8

Lead-Free Solder Paste | The Ames Laboratory  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 LawrenceE C H N I C A L TA L K <Lead-Free

9

Compatibility of lead-free solders with lead containing surface finishes as a reliability issue in electronic assemblies  

SciTech Connect (OSTI)

Enhanced performance goals and environmental restrictions have heightened the consideration for use of alternative solders as replacements for the traditional tin-lead (Sn-Pb) eutectic and near-eutectic alloys. However, the implementation of non-Pb bearing surface finishes may lag behind solder alloy development. A study was performed which examined the effect(s) of Pb contamination on the performance of Sn-Ag-Bi and Sn-Ag-Cu-Sb lead-free solders by the controlled addition of 63Sn-37Pb solder at levels of 0.5 {minus} 8.0 wt.%. Thermal analysis and ring-in-plug shear strength studies were conducted on bulk solder properties. Circuit board prototype studies centered on the performance of 20I/O SOIC gull wing joints. Both alloys exhibited declines in their melting temperatures with greater Sn-Pb additions. The ring-in-plug shear strength of the Sn-Ag-Cu-Sb solder increased slightly with Sn-Pb levels while the Sn-Ag-Bi alloy experienced a strength loss. The mechanical behavior of the SOIC (Small Outline Integrated Circuit) Sn-Ag-Bi solder joints reproduced the strength levels were insensitive to 10,106 thermal cycles. The Sn-Ag-Cu-Sb solder showed a slight decrease in the gull wing joint strengths that was sensitive to the Pb content of the surface finish.

Vianco, P.; Rejent, J. [Sandia National Labs., Albuquerque, NM (United States); Artaki, I.; Ray, U.; Finley, D.; Jackson, A. [AT and T Bell Labs., Princeton, NJ (United States)

1996-03-01T23:59:59.000Z

10

Suppressing tin whisker growth in lead-free solders and platings  

DOE Patents [OSTI]

A process of irradiation Sn containing Pb-free solder to mitigate whisker formation and growth thereon is provided. The use of gamma radiation such as cobalt-60 has been applied to a substrate of Sn on copper has been found to change the morphology of the crystalline whisker growth to a more truncated hillock pattern. The change in morphology greatly reduces the tendency of whiskers to contribute to electrical short-circuits being used as a Pb-free solder system on a copper substrate.

Hoffman, Elizabeth N; Lam, Poh-Sang

2014-04-29T23:59:59.000Z

11

Wave soldering with Pb-free solders  

SciTech Connect (OSTI)

The manufacturing feasibility and attachment reliability of a series of newly developed lead-free solders were investigated for wave soldering applications. Some of the key assembly aspects addressed included: wettability as a function of board surface finish, flux activation and surface tension of the molten solder, solder joint fillet quality and optimization of soldering thermal profiles. Generally, all new solder formulations exhibited adequate wave soldering performance and can be considered as possible alternatives to eutectic SnPb for wave soldering applications. Further process optimization and flux development is necessary to achieve the defect levels associated with the conventional SnPb process.

Artaki, I.; Finley, D.W.; Jackson, A.M.; Ray, U. [AT and T Bell Labs., Princeton, NJ (United States); Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1995-07-01T23:59:59.000Z

12

Lead Free Solder - Energy Innovation Portal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

TVs, and VCRs. Direct Link to Article:http:www.ameslab.govfilesTTsuccessstory-leadfreesolder.pdf Ames Laboratory Iowa State University Research Foundation - Office of...

13

Reactive Spreading of a Lead-Free Solder on Alumina  

SciTech Connect (OSTI)

The wetting of Sn3Ag-based alloys on Al{sub 2}O{sub 3} has been studied using the sessile-drop configuration. Small additions of Ti decrease the contact angle of Sn3Ag alloys on alumina from 115 to 23 degrees. Adsorption of Ti-species at the solid-liquid interface prior to reaction is the driving force for the observed decrease in contact angle, and the spreading kinetics is controlled by the kinetics of Ti dissolution into the molten alloy. The addition of Ti increases the transport rates at the solid-liquid interface, resulting in the formation of triple-line ridges that pin the liquid front and promote a wide variability in the final contact angles.

Gremillard, L.; Saiz, E.; Radmilovic, V.R.; Tomsia, A.P.

2005-12-01T23:59:59.000Z

14

Lab Breakthrough: Lead-free Solder | Department of Energy  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 LOS ALAMOS,Transition

15

Lead-Free Surface Finishes for Electronic Components  

E-Print Network [OSTI]

Lead-Free Surface Finishes for Electronic Components: Tin Whisker Growth METALS This project degraded by the switch to lead- free technology. In particular, the state of compressive stress and the localized creep response (whisker growth) of tin-based lead-free electrodeposits are being measured

16

Suppression of Tin Whiskers in Lead-Free Solder - Energy Innovation Portal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmosphericNuclear Security AdministrationcontrollerNanocrystalline Gallium

17

Soldering instrument safety improvements  

DOE Patents [OSTI]

A safe soldering device includes a retractable heat shield which can be moved between a first position in which the solder tip of the device is exposed for soldering operation and a second position in which the solder tip is covered by the heat shield. Preferably, the heat shield is biased towards the second position and may be locked in the first position for ease of use. When the soldering device is equipped with a vacuum system, the heat shield may serve to guide the flow of gases and heat from the solder tip away from the work area. The heat shield is preferably made of non-heatsinking plastic.

Kosslow, William J. (Jefferson Boro, PA); Giron, Ronald W. (Delmont, PA)

1996-01-01T23:59:59.000Z

18

Solderability test system  

DOE Patents [OSTI]

A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time. 11 figs.

Yost, F.; Hosking, F.M.; Jellison, J.L.; Short, B.; Giversen, T.; Reed, J.R.

1998-10-27T23:59:59.000Z

19

Solderability test system  

DOE Patents [OSTI]

A new test method to quantify capillary flow solderability on a printed wiring board surface finish. The test is based on solder flow from a pad onto narrow strips or lines. A test procedure and video image analysis technique were developed for conducting the test and evaluating the data. Feasibility tests revealed that the wetted distance was sensitive to the ratio of pad radius to line width (l/r), solder volume, and flux predry time.

Yost, Fred (Cedar Crest, NM); Hosking, Floyd M. (Albuquerque, NM); Jellison, James L. (Albuquerque, NM); Short, Bruce (Beverly, MA); Giversen, Terri (Beverly, MA); Reed, Jimmy R. (Austin, TX)

1998-01-01T23:59:59.000Z

20

KNN–NTK composite lead-free piezoelectric ceramic  

SciTech Connect (OSTI)

A (K,Na)NbO{sub 3}-based lead-free piezoelectric ceramic was successfully densified. It exhibited an enhanced electromechanical coupling factor of k{sub p}?=?0.52, a piezoelectric constant d{sub 33}?=?252 pC/N, and a frequency constant N{sub p}?=?3170?Hz m because of the incorporation of an elaborate secondary phase composed primarily of KTiNbO{sub 5}. The ceramic's nominal composition was 0.92K{sub 0.42}Na{sub 0.44}Ca{sub 0.04}Li{sub 0.02}Nb{sub 0.85}O{sub 3}–0.047K{sub 0.85}Ti{sub 0.85}Nb{sub 1.15}O{sub 5}–0.023BaZrO{sub 3} –0.0017Co{sub 3}O{sub 4}–0.002Fe{sub 2}O{sub 3}–0.005ZnO, abbreviated herein as KNN–NTK composite. The KNN–NTK ceramic exhibited a dense microstructure with few microvoids which significantly degraded its piezoelectric properties. Elemental maps recorded using transmission electron microscopy with energy-dispersive X-ray spectroscopy (TEM–EDS) revealed regions of high concentrations of Co and Zn inside the NTK phase. In addition, X-ray diffraction patterns confirmed that a small portion of the NTK phase was converted into K{sub 2}(Ti,Nb,Co,Zn){sub 6}O{sub 13} or CoZnTiO{sub 4} by a possible reaction between Co and Zn solutes and the NTK phase during a programmed sintering schedule. TEM studies also clarified a distortion around the KNN/NTK interfaces. Such an NTK phase filled voids between KNN particles, resulting in an improved chemical stability of the KNN ceramic. The manufacturing process was subsequently scaled to 100?kg per batch for granulated ceramic powder using a spray-drying technique. The properties of the KNN–NTK composite ceramic produced using the scaled-up method were confirmed to be identical to those of the ceramic prepared by conventional solid-state reaction sintering. Consequently, slight changes in the NTK phase composition and the distortion around the KNN/NTK interfaces affected the KNN–NTK composite ceramic's piezoelectric characteristics.

Matsuoka, T., E-mail: ta-matsuoka@mg.ngkntk.co.jp; Kozuka, H.; Kitamura, K.; Yamada, H.; Kurahashi, T.; Yamazaki, M.; Ohbayashi, K. [NGK SPARK PLUG Co., Ltd., 2808 Iwasaki, Komaki, Aichi 485-8510 (Japan)

2014-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Tin-silver-bismuth solders for electronics assembly  

DOE Patents [OSTI]

A lead-free solder alloy for electronic assemblies composed of a eutectic alloy of tin and silver with a bismuth addition, x, of 0

Vianco, Paul T. (Albuquerque, NM); Rejent, Jerome A. (Albuquerque, NM)

1995-01-01T23:59:59.000Z

22

Tin-silver-bismuth solders for electronics assembly  

DOE Patents [OSTI]

A lead-free solder alloy is disclosed for electronic assemblies composed of a eutectic alloy of tin and silver with a bismuth addition, x, of 0

Vianco, P.T.; Rejent, J.A.

1995-08-08T23:59:59.000Z

23

Lead-free precussion primer mixes based on metastable interstitial composite (MIC) technology  

DOE Patents [OSTI]

A lead-free percussion primer composition and a percussion cup containing e composition. The lead-free percussion primer composition is comprised of a mixture of about 45 wt % aluminum powder having an outer coating of aluminum oxide and molybdenum trioxide powder or a mixture of about 50 wt % aluminum powder having an outer coating of aluminum oxide and polytetrafluoroethylene powder. The aluminum powder, molybdenum trioxide powder and polytetrafluoroethylene powder has a particle size of 0.1 .mu.m or less, more preferably a particle size of from about 200-500 angstroms.

Dixon, George P. (Alexandria, VA); Martin, Joe A. (Espanola, NM); Thompson, Don (Ridgecrest, CA)

1998-01-01T23:59:59.000Z

24

Solder self-assembly for MEMS fabrication  

E-Print Network [OSTI]

This thesis examines and demonstrates self-assembly of MEMS components on the 25 micron scale onto substrates using the capillary force of solder. This is an order of magnitude smaller than current solder self-assembly in ...

Au, Hin Meng, 1977-

2004-01-01T23:59:59.000Z

25

Microstructural evolution of eutectic Au-Sn solder joints  

E-Print Network [OSTI]

resistance of electroless nickel- phosphorus coatings”,between solder and electroless nickel deposits”, Mater.packages soldered on electroless nickel/immersion gold”,

Song, Ho Geon

2002-01-01T23:59:59.000Z

26

Nano-soldering to single atomic layer  

DOE Patents [OSTI]

A simple technique to solder submicron sized, ohmic contacts to nanostructures has been disclosed. The technique has several advantages over standard electron beam lithography methods, which are complex, costly, and can contaminate samples. To demonstrate the soldering technique graphene, a single atomic layer of carbon, has been contacted, and low- and high-field electronic transport properties have been measured.

Girit, Caglar O. (Berkeley, CA); Zettl, Alexander K. (Kensington, CA)

2011-10-11T23:59:59.000Z

27

Organic solderability preservation evaluation. Topical report  

SciTech Connect (OSTI)

An evaluation was conducted to determine the possible replacement of the hot air solder leveling (HASL) process used in the Allied Signal Federal Manufacturing & Technologies (FM&T) Printed Wiring Board Facility with an organic solderability preservative (OSP). The drivers for replacing HASL include (1) Eliminating lead from PWB fabrication processes; (2) Potential legislation restricting use of lead, (3) Less expensive processing utilizing OSP rather than HASL processing; (4) Avoiding solder dross disposal inherent with HASL processing, (5) OSP provides flat, planar surface required for surface mount technology product, and (6) Trend to thinner PWB designs. A reduction in the cost of nonconformance (CONC) due to HASL defects (exposed copper, solderability, dewetting and non-wetting) would be realized with the incorporation of the OSP process. Several supplier HASL replacement candidates were initially evaluated. One supplier chemistry was chosen for potential use in the FM&T PWB and assembly areas.

Becka, G.A.; McHenry, M.R.; Slanina, J.T.

1997-03-01T23:59:59.000Z

28

alternative solder alloys: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

devices have involved developing structural integrity models for predicting the operating lifetime under vibratory and thermal environmental exposure. Solder joint...

29

Microstructural evolution of eutectic Au-Sn solder joints  

SciTech Connect (OSTI)

Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

Song, Ho Geon

2002-05-31T23:59:59.000Z

30

MODEL D650 INDUSTRIAL SOLDERING GUN PRODUCT DESCRIPTION  

E-Print Network [OSTI]

applications, a selection of soldering, cutting, and smoothing tips are available for the D650. OPERATING and with heat flows into the joint via capillary action, fusing the parts together. A properly soldered joint is considered both mechanically stable and electrically efficient. To correctly solder a joint, you need

Kleinfeld, David

31

Solder flow over fine line PWB surface finishes  

SciTech Connect (OSTI)

The rapid advancement of interconnect technology has stimulated the development of alternative printed wiring board (PWB) surface finishes to enhance the solderability of standard copper and solder-coated surfaces. These new finishes are based on either metallic or organic chemistries. As part of an ongoing solderability study, Sandia National Laboratories has investigated the solder flow behavior of two azole-based organic solderability preservations, immersion Au, immersion Ag, electroless Pd, and electroless Pd/Ni on fine line copper features. The coated substrates were solder tested in the as-fabricated and environmentally-stressed conditions. Samples were processed through an inerted reflow machine. The azole-based coatings generally provided the most effective protection after aging. Thin Pd over Cu yielded the best wetting results of the metallic coatings, with complete dissolution of the Pd overcoat and wetting of the underlying Cu by the flowing solder. Limited wetting was measured on the thicker Pd and Pd over Ni finishes, which were not completely dissolved by the molten solder. The immersion Au and Ag finishes yielded the lowest wetted lengths, respectively. These general differences in solderability were directly attributed to the type of surface finish which the solder came in contact with. The effects of circuit geometry, surface finish, stressing, and solder processing conditions are discussed.

Hosking, F.M.; Hernandez, C.L.

1998-08-01T23:59:59.000Z

32

Solder for oxide layer-building metals and alloys  

DOE Patents [OSTI]

A low temperature solder and method for soldering an oxide layer-building metal such as aluminum, titanium, tantalum or stainless steel. The comosition comprises tin and zinc; germanium as a wetting agent; preferably small amounts of copper and antimony; and a grit, such as silicon carbide. The grit abrades any oxide layer formed on the surface of the metal as the germanium penetrates beneath and loosens the oxide layer to provide good metal-to-metal contact. The germanium comprises less than aproximatley 10% by weight of the solder composition so that it provides sufficient wetting action but does not result in a melting temperature above approximately 300.degree. C. The method comprises the steps rubbing the solder against the metal surface so the grit in the solder abrades the surface while heating the surface until the solder begins to melt and the germanium penetrates the oxide layer, then brushing aside any oxide layer loosened by the solder.

Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

1992-01-01T23:59:59.000Z

33

Solder for oxide layer-building metals and alloys  

DOE Patents [OSTI]

A low temperature solder and method for soldering an oxide layer-building metal such as aluminum, titanium, tantalum or stainless steel is disclosed. The composition comprises tin and zinc; germanium as a wetting agent; preferably small amounts of copper and antimony; and a grit, such as silicon carbide. The grit abrades any oxide layer formed on the surface of the metal as the germanium penetrates beneath and loosens the oxide layer to provide good metal-to-metal contact. The germanium comprises less than approximately 10% by weight of the solder composition so that it provides sufficient wetting action but does not result in a melting temperature above approximately 300 C. The method comprises the steps rubbing the solder against the metal surface so the grit in the solder abrades the surface while heating the surface until the solder begins to melt and the germanium penetrates the oxide layer, then brushing aside any oxide layer loosened by the solder.

Kronberg, J.W.

1992-09-15T23:59:59.000Z

34

E-Print Network 3.0 - assisted soldering effects Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

a detrimental effect on the strength of the solder joint. Internal strains within... to surface tension and wetting effects, thus causing strains as the solder solidifies....

35

High temperature solder alloys for underhood applications: Final report  

SciTech Connect (OSTI)

In this continued study, the microstructural evolution and peel strength as a function of thermal aging were evaluated for four Sn-Ag solders deposited on double layered Ag-Pt metallization. Additionally, activation energies for intermetallic growth over the temperature range of 134 to 190{degrees}C were obtained through thickness measurements of the Ag-Sn intermetallic that formed at the solder-metallization interface. It was found that Bi-containing solders yielded higher activation energies for the intermetallic growth, leading to thicker intermetallic layers at 175 and 190{degrees}C for times of 542 and 20.5 hrs, respectively, than the solders free of Bi. Complete reaction of the solder with the metallization occurred and lower peel strengths were measured on the Bi-containing solders. In all solder systems, a Ag-Sn intermetallic thickness of greater than {approximately}7 {mu}m contributed to lower peel strength values. The Ag-Sn binary eutectic composition and the Ag-Sn-Cu ternary eutectic composition solders yielded lower activation energies for intermetallic formation, less microstructural change with time, and higher peel strengths; these solder systems were resilient to the effects of temperatures up to 175{degrees}C. Accelerated isothermal aging studies provide useful criteria for recommendation of materials systems. The Sn-Ag and Sn-Ag-Cu eutectic compositions should be considered for future service life and reliability studies based upon their performance in this study.

Kern, J.A. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering; Drewien, C.A.; Yost, F.G.; Sackinger, S. [Sandia National Laboratories, Albuquerque, NM (United States); Weiser, M.W. [Johnson-Mathey Electronics Corp., Spokane, WA (United States)

1996-06-01T23:59:59.000Z

36

Hot-stage transmission electron microscopy study of (Na, K)NbO{sub 3} based lead-free piezoceramics  

SciTech Connect (OSTI)

Hierarchical nanodomains assembled into micron-sized stripe domains, which is believed to be associated with outstanding piezoelectric properties, were observed at room temperature in a typical lead free piezoceramics, (Na{sub 0.52}K{sub 0.48?x})(Nb{sub 0.95?x}Ta{sub 0.05})-xLiSbO{sub 3}, with finely tuned polymorphic phase boundaries (x?=?0.0465) by transmission electron microscopy. The evolution of domain morphology and crystal structure under heating and cooling cycles in the ceramic was investigated by in-situ hot stage study. It is found that the nanodomains are irreversibly transformed into micron-sized rectangular domains during heating and cooling cycles, which lead to the thermal instability of piezoelectric properties of the materials.

Lu, Shengbo, E-mail: shengbo.lu@yahoo.com [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Xu, Zhengkui [Department of Physics and Materials Science, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon (Hong Kong); Kwok, K. W.; Chan, Helen L. W. [Department of Applied Physics and Materials Research Centre, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

2014-07-28T23:59:59.000Z

37

Mechanical confinement for improved energy storage density in BNT-BT-KNN lead-free ceramic capacitors  

SciTech Connect (OSTI)

With the advent of modern power electronics, embedded circuits and non-conventional energy harvesting, the need for high performance capacitors is bound to become indispensible. The current state-of-art employs ferroelectric ceramics and linear dielectrics for solid state capacitance. However, lead-free ferroelectric ceramics propose to offer significant improvement in the field of electrical energy storage owing to their high discharge efficiency and energy storage density. In this regards, the authors have investigated the effects of compressive stress as a means of improving the energy storage density of lead-free ferroelectric ceramics. The energy storage density of 0.91(Bi{sub 0.5}Na{sub 0.5})TiO{sub 3}-0.07BaTiO{sub 3}-0.02(K{sub 0.5}Na{sub 0.5})NbO{sub 3} ferroelectric bulk ceramic was analyzed as a function of varying levels of compressive stress and operational temperature .It was observed that a peak energy density of 387 mJ.cm{sup -3} was obtained at 100 MPa applied stress (25{sup o}C). While a maximum energy density of 568 mJ.cm{sup -3} was obtained for the same stress at 80{sup o}C. These values are indicative of a significant, 25% and 84%, improvement in the value of stored energy compared to an unloaded material. Additionally, material's discharge efficiency has also been discussed as a function of operational parameters. The observed phenomenon has been explained on the basis of field induced structural transition and competitive domain switching theory.

Chauhan, Aditya; Patel, Satyanarayan; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, 175 001 (India)

2014-08-15T23:59:59.000Z

38

RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS  

E-Print Network [OSTI]

RADIATION HEAT TRANSFER IN TISSUE WELDING AND SOLDERING WITH ULTRAFAST LASERS Kyunghan Kim to incorporate transient radiation heat transfer in tissue welding and soldering with use of ultrafast lasers are performed between laser welding and laser soldering. The use of solder is found to substantially enhance

Guo, Zhixiong "James"

39

The influence of microstructure on the mechanical properties of solder  

SciTech Connect (OSTI)

Solder joints in microelectronics devices consist of low-melting solder compositions that wet and join metal contacts and are, ordinarily, used at high homologous temperatures in the as-solidified condition. Differences in solidification rate and substrate interactions have the consequence that even solder joints of similar compositions exhibit a wide range of microstructures. The variation in microstructure causes a variation in properties; in particular, the high-temperature creep properties that govern much of the mechanical behavior of the solder may differ significantly from joint to joint. The present paper reviews the varieties of microstructure that are found in common solder joints, and describes some of the ways in which microstructural changes affect mechanical properties and joint reliability.

Morris, J.W. Jr.; Reynolds, H.L.

1996-06-01T23:59:59.000Z

40

Dry soldering with hot filament produced atomic hydrogen  

DOE Patents [OSTI]

A system is disclosed for chemically transforming metal surface oxides to metal that is especially, but not exclusively, suitable for preparing metal surfaces for dry soldering and solder reflow processes. The system employs one or more hot, refractory metal filaments, grids or surfaces to thermally dissociate molecular species in a low pressure of working gas such as a hydrogen-containing gas to produce reactive species in a reactive plasma that can chemically reduce metal oxides and form volatile compounds that are removed in the working gas flow. Dry soldering and solder reflow processes are especially applicable to the manufacture of printed circuit boards, semiconductor chip lead attachment and packaging multichip modules. The system can be retrofitted onto existing metal treatment ovens, furnaces, welding systems and wave soldering system designs. 1 fig.

Panitz, J.K.G.; Jellison, J.L.; Staley, D.J.

1995-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Solder extrusion pressure bonding process and bonded products produced thereby  

DOE Patents [OSTI]

Disclosed is a process for production of soldered joints which are highly reliable and capable of surviving 10,000 thermal cycles between about [minus]40 C and 110 C. Process involves interposing a thin layer of a metal solder composition between the metal surfaces of members to be bonded and applying heat and up to about 1000 psi compression pressure to the superposed members, in the presence of a reducing atmosphere, to extrude the major amount of the solder composition, contaminants including fluxing gases and air, from between the members being bonded, to form a very thin, strong intermetallic bonding layer having a thermal expansion tolerant with that of the bonded members.

Beavis, L.C.; Karnowsky, M.M.; Yost, F.G.

1992-06-16T23:59:59.000Z

42

Solder extrusion pressure bonding process and bonded products produced thereby  

DOE Patents [OSTI]

Production of soldered joints which are highly reliable and capable of surviving 10,000 thermal cycles between about -40.degree. C. and 110.degree. C. Process involves interposing a thin layer of a metal solder composition between the metal surfaces of members to be bonded and applying heat and up to about 1000 psi compression pressure to the superposed members, in the presence of a reducing atmosphere, to extrude the major amount of the solder composition, contaminants including fluxing gases and air, from between the members being bonded, to form a very thin, strong intermetallic bonding layer having a thermal expansion tolerant with that of the bonded members.

Beavis, Leonard C. (Albuquerque, NM); Karnowsky, Maurice M. (Albuquerque, NM); Yost, Frederick G. (Ceder Crest, NM)

1992-01-01T23:59:59.000Z

43

Structural, microstructural and thermal properties of lead-free bismuth–sodium–barium–titanate piezoceramics synthesized by mechanical alloying  

SciTech Connect (OSTI)

Graphical abstract: Mechano-synthesis of lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} piezoceramics with nanocrystalline/amorphous structure and homogeneous composition: partial transformation of constituents to BNBT, BNT and pyrochlore, amorphous phase formation, mechano-crystallization of the amorphous, pyrochlore-to-perovskite BNBT phase transformation during the process. Display Omitted Highlights: ? Perovskite BNBT powders with homogeneous composition were synthesized by MA. ? Partial transformation of constituents to BNBT, BNT and pyrochlore occurred by MA. ? Formation of an amorphous phase and afterwards its crystallization occurred by MA. ? Pyrochlore-to-perovskite BNBT phase transformation occurred after prolong milling. ? Polymorphic transformations of TiO{sub 2} act as the main alloying impediment during MA. -- Abstract: Bismuth–sodium–barium–titanate piezoceramics with a composition of (Bi{sub 0.5}Na{sub 0.5}){sub 0.94}Ba{sub 0.06}TiO{sub 3} (BNBT) were prepared by mechanical alloying (MA). Structural analysis and phase identification were performed by X-ray diffraction (XRD). Microstructural studies and chemical composition homogeneity were performed by scanning electron microscope (SEM) coupled with energy dispersive X-ray analysis (EDX). Furthermore, thermal properties of the as-milled powders were evaluated by thermogravimetry/differential thermal analysis (TG/DTA). During the initial milling, the constituents were transformed to the perovskite, pyrochlore, and BNT phases; in addition, partial amorphization of the structure appeared during the milling cycle. As MA progressed, transformation of pyrochlore-to-perovskite and crystallization of the amorphous phase occurred and also, the BNBT phase was significantly developed. It was found that the MA process has the ability to synthesize the BNBT powders with a submicron particle size, regular morphology, and uniform elemental distribution.

Amini, Rasool, E-mail: amini@sutech.ac.ir [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of)] [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of); Ghazanfari, Mohammad Reza; Alizadeh, Morteza; Ardakani, Hamed Ahmadi [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of)] [Department of Materials Science and Engineering, Shiraz University of Technology, 71557-13876 Shiraz (Iran, Islamic Republic of); Ghaffari, Mohammad [Department of Electrical and Electronics Engineering, UNAM—National Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)] [Department of Electrical and Electronics Engineering, UNAM—National Institute of Materials Science and Nanotechnology, Bilkent University, Ankara 06800 (Turkey)

2013-02-15T23:59:59.000Z

44

The role of eddy currents and nanoparticle size on AC magnetic fieldinduced reflow in solder/magnetic nanocomposites  

E-Print Network [OSTI]

facilitate solder reflow in AC magnetic fields. We compare power loss in a solder composite sample with MNP, for smaller samples, power loss is not sufficient to realize solder reflow temperature. Additional heating can powders (Power loss in magnetic

McHenry, Michael E.

45

1-4244-0665-X/06/$20.00 2006 IEEE 781 2006 Electronics Packaging Technology Conference Development of Life Prediction Model for Lead-free Solder at Chip Resistor  

E-Print Network [OSTI]

1-4244-0665-X/06/$20.00 Ā©2006 IEEE 781 2006 Electronics Packaging Technology Conference Development Reliability & Failure Analysis Center Korea Electronics Technology Institute Seongnam 463-816, South Korea E have been extensively used more than fifty years in the electronics industry with many advantages

Berlin,Technische UniversitƤt

46

Solder fatigue reduction in point focus photovoltaic concentrator modules  

SciTech Connect (OSTI)

Solder fatigue tests have been conducted on point focus photovoltaic concentration cell assemblies to identify a baseline fatigue life and to quantify the fatigue life improvements that result using a copper-molybdenum-copper low-expansion insert between the solar cell and copper heat spreader. Solder microstructural changes and fatigue crack growth were identified using cross sections and ultrasonic scans of the fatigue solder joints. The Coffin-Manson and Total Strain fatigue models for low-cycle fatigue were evaluated for use in fatigue life predictions. Since both of these models require strain calculations, two strain calculation methods were compared: hand-calculated shear strain and a finite element method shear strain. At present, the available theoretical models for low-cycle solder fatigue are limited in their ability to predict failure; consequently, extensive thermal cycling is continuing to define the fatigue life for point focus photovoltaic cell assemblies. 9 refs., 9 figs., 2 tabs.

Hund, T.D.; Burchett, S.N.

1991-01-01T23:59:59.000Z

47

Substrate solder barriers for semiconductor epilayer growth  

DOE Patents [OSTI]

During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In modular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substrate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating.

Drummond, Timothy J. (Tijeras, NM); Ginley, David S. (Albuquerque, NM); Zipperian, Thomas E. (Albuquerque, NM)

1989-01-01T23:59:59.000Z

48

Substrate solder barriers for semiconductor epilayer growth  

DOE Patents [OSTI]

During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In modular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substrate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating.

Drummond, T.J.; Ginley, D.S.; Zipperian, T.E.

1989-05-09T23:59:59.000Z

49

Substrate solder barriers for semiconductor epilayer growth  

DOE Patents [OSTI]

During the growth of compound semiconductors by epitaxial processes, substrates are typically mounted to a support. In molecular beam epitaxy, mounting is done using indium as a solder. This method has two drawbacks: the indium reacts with the substrate, and it is difficult to uniformly wet the back of a large diameter substrate. Both of these problems have been successfully overcome by sputter coating the back of the substrate with a thin layer of tungsten carbide or tungsten carbide and gold. In addition to being compatible with the growth of high quality semiconductor epilayers this coating is also inert in all standard substate cleaning etchants used for compound semiconductors, and provides uniform distribution of energy in radiant heating. 1 tab.

Drummond, T.J.; Ginley, D.S.; Zipperian, T.E.

1987-10-23T23:59:59.000Z

50

au-sn solder joints: Topics by E-print Network  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

devices have involved developing structural integrity models for predicting the operating lifetime under vibratory and thermal environmental exposure. Solder joint...

51

A novel photovoltaic-module assembly system for back contact solar cells using laser soldering technique  

E-Print Network [OSTI]

A novel photovoltaic-module assembly system for back contact solar cells using laser soldering that the conventional soldering process is still more reliable compared to conductive adhesives or low melting solder alloys. The aim of this work is to combine the reliability of the conventional module assembling

52

An Overview of Surface Finishes and Their Role in Printed Circuit Board Solderability and Solder Joint Performance  

SciTech Connect (OSTI)

A overview has been presented on the topic of alternative surface finishes for package I/Os and circuit board features. Aspects of processability and solder joint reliability were described for the following coatings: baseline hot-dipped, plated, and plated-and-fused 100Sn and Sn-Pb coatings; Ni/Au; Pd, Ni/Pd, and Ni/Pd/Au finishes; and the recently marketed immersion Ag coatings. The Ni/Au coatings appear to provide the all-around best option in terms of solderability protection and wire bondability. Nickel/Pal ftishes offer a slightly reduced level of performance in these areas that is most likely due to variable Pd surface conditions. It is necessmy to minimize dissolved Au or Pd contents in the solder material to prevent solder joint embrittlement. Ancillary aspects that included thickness measurement techniques; the importance of finish compatibility with conformal coatings and conductive adhesives; and the need for alternative finishes for the processing of non-Pb bearing solders were discussed.

Vianco, P.T.

1998-10-15T23:59:59.000Z

53

Development of alternatives to lead-bearing solders  

SciTech Connect (OSTI)

Soldering technology, using tin-lead alloys has had a significant role in the packaging of highly functional, low cost electronic devices. The elimination of lead from all manufactured products, whether through legislation or tax incentives, will impact the electronics community which uses lead-containing solders. In response to these proposed measures, the National Center for Manufacturing Sciences has established a multi-year program involving participants from industry, academia, and the national laboratories with the objective to identify potential replacements for lead-bearing solders. Selection of candidate alloys is based upon the analysis of materials properties, manufacturability, modeling codes for reliability prediction, as well as toxicological properties and resource availability, data developed in the program.

Vianco, P.T. [Sandia National Labs., Albuquerque, NM (United States)

1993-07-01T23:59:59.000Z

54

Method and apparatus for jetting, manufacturing and attaching uniform solder balls  

DOE Patents [OSTI]

An apparatus and process for jetting molten solder in the form of balls directly onto all the metallized interconnects lands for a ball grid array package in one step with no solder paste required. Molten solder is jetted out of a grid of holes using a piston attached to a piezoelectric crystal. When voltage is applied to the crystal it expands forcing the piston to extrude a desired volume of solder through holes in the aperture plate. When the voltage is decreased the piston reverses motion creating an instability in the molten solder at the aperture plate surface and thereby forming spherical solder balls that fall onto a metallized substrate. The molten solder balls land on the substrate and form a metallurgical bond with the metallized lands. The size of the solder balls is determined by a combination of the size of the holes in the aperture plate, the duration of the piston pulse, and the displacement of the piston. The layout of the balls is dictated by the location of the hooks in the grid. Changes in ball size and layout can be easily accomplished by changing the grid plate. This invention also allows simple preparation of uniform balls for subsequent supply to BGA users.

Yost, Frederick G. (Cedar Crest, NM); Frear, Darrel R. (Albuquerque, NM); Schmale, David T. (Albuquerque, NM)

1999-01-01T23:59:59.000Z

55

Method and apparatus for jetting, manufacturing and attaching uniform solder balls  

DOE Patents [OSTI]

An apparatus and process are disclosed for jetting molten solder in the form of balls directly onto all the metallized interconnects lands for a ball grid array package in one step with no solder paste required. Molten solder is jetted out of a grid of holes using a piston attached to a piezoelectric crystal. When voltage is applied to the crystal it expands forcing the piston to extrude a desired volume of solder through holes in the aperture plate. When the voltage is decreased the piston reverses motion creating an instability in the molten solder at the aperture plate surface and thereby forming spherical solder balls that fall onto a metallized substrate. The molten solder balls land on the substrate and form a metallurgical bond with the metallized lands. The size of the solder balls is determined by a combination of the size of the holes in the aperture plate, the duration of the piston pulse, and the displacement of the piston. The layout of the balls is dictated by the location of the hooks in the grid. Changes in ball size and layout can be easily accomplished by changing the grid plate. This invention also allows simple preparation of uniform balls for subsequent supply to BGA users. 7 figs.

Yost, F.G.; Frear, D.R.; Schmale, D.T.

1999-01-05T23:59:59.000Z

56

Pb-free Sn-Ag-Cu ternary eutectic solder  

DOE Patents [OSTI]

A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

1996-06-18T23:59:59.000Z

57

Solder Joint Materials By Design | Department of Energy  

Energy Savers [EERE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartment of Energyof the Americas |DOEEnergy SmoothSolar IndustrySB 2SolarSolder Joint

58

Characterization and optimization of a Hot Air Solder-Leveling System  

SciTech Connect (OSTI)

The characterization and optimization of a new Hot Air Sokkr-Leveling (HASL) System in the Printed Wiring Board Fabrication Area was initiated to reduce the variability and defects in printed wiring board solder coatings. This body of work continues to provide information on the mechanics of solder coating, and allows us to predict the required process adjustments based on board type and geometry. The previous HASL system contained several processes (flux, preheat, solder-coat, cooldown) within one piece of equipment. The new system physically separates these processes using in-line conveyors. Parameters affecting these processes were brainstormed and evaluated using the MaHo Perez-Wilson methodology (MPCpS). The critical parameters were identified and segregated according to individual process. Each process was characterized for materials used, machine settings, and their effect (potential and actual) on product. Due to the wide-ranging affect of the preheat and solder-leveling machine settings, the first decision made was to restrict the characterization to duplication of the coating obtained from the previous system. Adoption of the parameters used on the previous system allowed a reduction in the number of evaluations required to establish initial machine settings (solder pot dwell times, solder temperature, preheat temperature, etc.). Activities in-work include a formal statistical analysis of the solder-leveling capabilities, and completion of Optimization activities.

Penniston, R.R. Jr.; Stockdale, D.A.

1993-03-01T23:59:59.000Z

59

Microstructurally based thermomechanical fatigue lifetime model of solder joints for electronic applications  

SciTech Connect (OSTI)

We present a new methodology for predicting the fatigue life of solder joints for electronics applications. This approach involves integration of experimental and computational techniques. The first stage involves correlating the manufacturing and processing parameters with the starting microstructure of the solder joint. The second stage involves a series of experiments that characterize the evolution of the microstructure during thermal cycling. The third stage consists of a computer modeling and simulation effort that utilizes the starting microstructure and experimental data to produce a reliability prediction of the solder joint. This approach is an improvement over current methodologies because it incorporates the microstructure and properties of the solder directly into the model and allows these properties to evolve as the microstructure changes during fatigue.

Frear, D.R.; Rashid, M.M.; Burchett, S.N.

1993-07-01T23:59:59.000Z

60

Understanding, Modeling and Predicting Hidden Solder Joint Shape Using Active Thermography  

E-Print Network [OSTI]

Characterizing hidden solder joint shapes is essential for electronics reliability. Active thermography is a methodology to identify hidden defects inside an object by means of surface abnormal thermal response after applying a heat flux...

Giron Palomares, Jose

2012-07-16T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Effects of surface properties on solder bump formation by direct droplet deposition  

E-Print Network [OSTI]

Recent advances in microdroplet generation and deposition processes have made it possible to directly form solder bumps on integrated circuits using micron-sized molten metal droplets. The direct droplet deposition bumping ...

Hsiao, Wen Kai, 1972-

2004-01-01T23:59:59.000Z

62

Root cause analysis of solder flux residue incidence in the manufacture of electronic power modules  

E-Print Network [OSTI]

This work investigates the root causes of the incidence of solder flux residue underneath electronic components in the manufacture of power modules. The existing deionized water-based centrifugal cleaning process was ...

Jain, Pranav

2011-01-01T23:59:59.000Z

63

Modeling and implementation of solder-activated joints for single actuator, centimeter-scale robotic mechanisms  

E-Print Network [OSTI]

This thesis explains when, and why, solder-based phase change materials (PCMs) are best-suited as a means to modify a robotic mechanism's kinematic and elastomechanic behavior. The preceding refers to mechanisms that possess ...

Telleria, Maria J

2010-01-01T23:59:59.000Z

64

Evaluation of low-residue soldering for military and commercial applications: A report from the Low-Residue Soldering Task Force  

SciTech Connect (OSTI)

The LRSTF combined the efforts of industry, military, and government to evaluate low-residue soldering processes for military and commercial applications. These processes were selected for evaluation because they provide a means for the military to support the presidential mandate while producing reliable hardware at a lower cost. This report presents the complete details and results of a testing program conducted by the LRSTF to evaluate low-residue soldering for printed wiring assemblies. A previous informal document provided details of the test plan used in this evaluation. Many of the details of that test plan are contained in this report. The test data are too massive to include in this report, however, these data are available on disk as Excel spreadsheets upon request. The main purpose of low-residue soldering is to eliminate waste streams during the manufacturing process.

Iman, R.L.; Anderson, D.J. [Sandia National Labs., Albuquerque, NM (United States); Burress, R.V. [SEHO (United States)] [and others

1995-06-01T23:59:59.000Z

65

Description of a solder pulse generator for the single step formation of ball grid arrays  

SciTech Connect (OSTI)

The traditional geometry for surface mount devices is the peripheral array where the leads are on the edges of the device. As the technology drives towards high input/output (I/O) count (increasing number of leads) and smaller packages with finer pitch (less distance between peripheral leads), limitations on peripheral surface mount devices arise. The leads on these fine pitch devices are fragile and can be easily bent. It becomes increasingly difficult to deliver solder past to leads spaced as little as 0.012 inch apart. Too much solder mass can result in bridging between leads while too little solder can contribute to the loss of mechanical and electrical continuity. A solution is to shift the leads from the periphery of the device to the area under the device. This scheme is called areal array packaging and is exemplified by the ball grid array (BGA) package. A system has been designed and constructed to deposit an entire array of several hundred uniform solder droplets onto a printed circuit board in a fraction of a second. The solder droplets wet to the interconnect lands on a pc board and forms a basis for later application of a BGA device. The system consists of a piezoelectric solder pulse unit, heater controls, an inert gas chamber and an analog power supply/pulse unit.

Schmale, D.T.; Frear, D.R.; Yost, F.G.; Essien, M. [Sandia National Labs., Albuquerque, NM (United States). Materials and Process Sciences Center

1997-02-01T23:59:59.000Z

66

Effect of gold-nickel metallization microstructure on fluxless soldering  

SciTech Connect (OSTI)

Gold plating is used in the microelectronics industry to maintain the wettability of metal substrates. The nature of wetting during soldering of gold plated metals is discussed, and the results of experiments on the fluxless wettability and oxidation of gold plated nickel are described. The results suggest that electrodeposition of a thin gold plate (0.14 [mu]m) and the concurrent reduction of nickel oxide produce a gold-nickel system which will wet without flux. Oxidation of nickel was observed to occur via nickel out-diffusion and by direct exposure of the substrate through pinhole plating defects. Auger chemical analysis indicates that pinholes do not produce oxidation of the surrounding substrate area. 20 refs., 10 figs.

Cinque, R.B.; Morris, J.W. Jr. (Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley, CA (United States))

1994-06-01T23:59:59.000Z

67

Bonding Low-density Nanoporous Metal Foams Using Sputtered Solder  

SciTech Connect (OSTI)

A method has been developed for bonding low-density nanoporous metal foam components to a substrate using solder that is sputtered onto the surfaces. Metal foams have unusual properties that make them excellent choices for many applications, and as technologies for processing these materials are evolving, their use in industry is increasing dramatically. Metal foams are lightweight and have advantageous dynamic properties, which make them excellent choices for many structural applications. They also provide good acoustic damping, low thermal conductivity, and excellent energy absorption characteristics. Therefore, these materials are commonly used in the automotive, aerospace, construction, and biomedical industries. The synthesis of nanoporous metal foams with a cell size of less then 1 {micro}m is an emerging technology that is expected to lead to widespread application of metal foams in microdevices, such as sensors and actuators. One of the challenges to manufacturing components from metal foams is that they can be difficult to attach to other structures without degrading their properties. For example, traditional liquid adhesives cannot be used because they are absorbed into foams. The problem of bonding or joining can be particularly difficult for small-scale devices made from nanoporous foam, due to the requirement for a thin bond layer. The current study addresses this problem and develops a method of soldering a nanoporous metal foam to a substrate with a bond thickness of less than 2 {micro}m. There are many applications that require micro-scale metal foams precisely bonded to substrates. This study was motivated by a physics experiment that used a laser to drive a shock wave through an aluminum foil and into a copper foam, in order to determine the speed of the shock in the copper foam. To avoid disturbing the shock, the interface between the copper foam and the aluminum substrate had to be as thin as possible. There are many other applications that could benefit from the bonding technology developed in this study, such as small-scale lightweight structural members, high-strength thermal insulating layers for electronics, and micro-scale mechanical dampers, to name but a few. Each of these applications requires one or more small metal foam components precisely bonded to a substrate. Several methods for bonding metal foam components have been developed by previous researchers. Macroscopic metal foam parts have been successfully bonded by laser welding to create T-sections and butt joints. Ultrasonic welding has been used to join aluminum sheet metal to aluminum foam for structural applications. These methods work well for bonding large foam components, but reducing these methods to a smaller length scale would be challenging. One method that has shown great potential for bonding layers of metal foams to substrates is a brazing process that uses a sputter-deposited interface material. Shirzadi et al.[9] have demonstrated bonds between stainless steel foam and a stainless steel substrate using a layer of copper-titanium filler metal that is sputtered onto the interface surfaces. The foam pieces that they bonded were approximately 10 mm in diameter and 10 mm thick with a cell size of approximately 200 {micro}m. After depositing the filler material, pressing the materials together, and heating them with an induction heater, bonds were achieved without causing significant damage to the foam. The current study also uses a sputter-deposited interface material to bond foam to a substrate. However, in contrast to previous work, the current study examines bonding microscale pieces of fragile nanoporous metal foam. In this study, a method is developed to bond a thin sheet of fragile, low-density nanoporous copper foam to an aluminum foil substrate of thickness 40 {micro}m. By sputter depositing an indium-silver alloy onto the foam and the substrate, a solder joint with a thickness of less than 2 {micro}m was achieved.

Bono, M; Cervantes, O; Akaba, C; Hamza, A; Foreman, R; Teslich, N

2007-08-21T23:59:59.000Z

68

IEEE TRANSACTIONS ON MAGNETICS, VOL. 46, NO. 6, JUNE 2010 2187 Novel Solder-Magnetic Particle Composites and  

E-Print Network [OSTI]

Terms--Electromagnetic induction heating, infrared imaging, magnetic nanoparticles, solder reflow. I University, Pittsburgh, PA 15213 USA Intel Corporation, Chandler, AZ 85226 USA Localized heating of solder reflow process, where the package is subjected to high temperatures. Localized heating is possible

McHenry, Michael E.

69

In-situ study of electromigration-induced grain rotation in Pb-free solder joint by synchrotron microdiffraction  

SciTech Connect (OSTI)

The rotation of Sn grains in Pb-free flip chip solder joints hasn't been reported in literature so far although it has been observed in Sn strips. In this letter, we report the detailed study of the grain orientation evolution induced by electromigration by synchrotron based white beam X-ray microdiffraction. It is found that the grains in solder joint rotate more slowly than in Sn strip even under higher current density. On the other hand, based on our estimation, the reorientation of the grains in solder joints also results in the reduction of electric resistivity, similar to the case of Sn strip. We will also discuss the reason why the electric resistance decreases much more in strips than in the Sn-based solders, and the different driving force for the grain growth in solder joint and in thin film interconnect lines.

Chen, Kai; Tamura, Nobumichi; Tu, King-Ning

2008-10-31T23:59:59.000Z

70

Design of Experiments to Determine Causes of Flex Cable Solder Wicking, Discoloration and Hole Location Defects  

SciTech Connect (OSTI)

Design of Experiments (DoE) were developed and performed in an effort to discover and resolve the causes of three different manufacturing issues; large panel voids after Hot Air Solder Leveling (HASL), cable hole locations out of tolerance after lamination and delamination/solder wicking around flat flex cable circuit lands after HASL. Results from a first DoE indicated large panel voids could be eliminated by removing the pre-HASL cleaning. It also revealed eliminating the pre-HASL bake would not be detrimental when using a hard press pad lamination stackup. A second DoE indicated a reduction in hard press pad stackup lamination pressure reduced panel stretch in the y axis approximately 70%. A third DoE illustrated increasing the pre-HASL bake temperature could reduce delamination/solder wicking when using a soft press pad lamination stackup.

Wolfe, Larry

2009-04-22T23:59:59.000Z

71

Sensitivity of Solder Joint Fatigue to Sources of Variation in Advanced Vehicular Power Electronics Cooling  

SciTech Connect (OSTI)

This paper demonstrates a methodology for taking variation into account in thermal and fatigue analyses of the die attach for an inverter of an electric traction drive vehicle. This method can be used to understand how variation and mission profile affect parameters of interest in a design. Three parameters are varied to represent manufacturing, material, and loading variation: solder joint voiding, aluminum nitride substrate thermal conductivity, and heat generation at the integrated gate bipolar transistor. The influence of these parameters on temperature and solder fatigue life is presented. The heat generation loading variation shows the largest influence on the results for the assumptions used in this problem setup.

Vlahinos, A.; O'Keefe, M.

2010-06-01T23:59:59.000Z

72

Comparison of Extensive Thermal Cycling Effects on Microstructure Development in Micro-alloyed Sn-Ag-Cu Solder Joints  

SciTech Connect (OSTI)

Pb-free solder alloys based on the Sn-Ag-Cu (SAC) ternary eutectic have promise for widespread adoption across assembly conditions and operating environments, but enhanced microstructural control is needed. Micro-alloying with elements such as Zn was demonstrated for promoting a preferred solidification path and joint microstructure earlier in simple (Cu/Cu) solder joints studies for different cooling rates. This beneficial behavior now has been verified in reworked ball grid array (BGA) joints, using dissimilar SAC305 (Sn-3.0Ag-0.5Cu, wt.%) solder paste. After industrial assembly, BGA components joined with Sn-3.5Ag-0.74Cu-0.21Zn solder were tested in thermal cycling (-55 C/+125 C) along with baseline SAC305 BGA joints beyond 3000 cycles with continuous failure monitoring. Weibull analysis of the results demonstrated that BGA components joined with SAC + Zn/SAC305 have less joint integrity than SAC305 joints, but their lifetime is sufficient for severe applications in consumer, defense, and avionics electronic product field environments. Failure analysis of the BGA joints revealed that cracking did not deviate from the typical top area (BGA component side) of each joint, in spite of different Ag3Sn blade content. Thus, SAC + Zn solder has not shown any advantage over SAC305 solder in these thermal cycling trials, but other characteristics of SAC + Zn solder may make it more attractive for use across the full range of harsh conditions of avionics or defense applications.

Anderson, Iver E.; Boesenberg, Adam; Harringa, Joel; Riegner, David; Steinmetz, Andrew; Hillman, David

2011-09-28T23:59:59.000Z

73

Energy Blog | Department of Energy  

Broader source: Energy.gov (indexed) [DOE]

May 24, 2012 Lab Breakthrough: Lead-free Solder Iver Anderson, Ames National Laboratory materials scientist, discusses the impact of a lead-free solder he invented 15 years ago,...

74

Assessment of Solder Interconnect Integrity in Dismantled Electronic Components from N57 and B61 Tube-Type Radars  

SciTech Connect (OSTI)

Aging analyses were performed on solder joints from two radar units: (1) a laboratory, N57 tube-type radar unit and (2) a field-returned, B61-0, tube-type radar unit. The cumulative temperature environments experienced by the units during aging were calculated from the intermetallic compound layer thickness and the mean Pb-rich phase particle size metrics for solder joints in the units, assuming an aging time of 35 years for both radars. Baseline aging metrics were obtained from a laboratory test vehicle assembled at AS/FM and T; the aging kinetics of both metrics were calculated from isothermal aging experiments. The N57 radar unit interconnect board solder joints exhibited very little aging. The eyelet solder joints did show cracking that most likely occurred at the time of assembly. The eyelet, SA1126 connector solder joints, showed some delamination between the Cu pad and underlying laminate. The B61 field-returned radar solder joints showed a nominal degree of aging. Cracking of the eyelet solder joints was observed. The Pb-rich phase particle measurements indicated additional aging of the interconnects as a result of residual stresses. Cracking of the terminal pole connector, pin-to-pin solder joint was observed; but it was not believed to jeopardize the electrical functionality of the interconnect. Extending the stockpile lifetime of the B61 tube-type radar by an additional 20 years would not be impacted by the reliability of the solder joints with respect to further growth of the intermetallic compound layer. Additional coarsening of the Pb-rich phase will increase the joints' sensitivity to thermomechanical fatigue.

Rejent, J.A.; Vianco, P.T.; Woodrum, R.A.

1999-07-01T23:59:59.000Z

76

Reliability of Nano-Structured Nickel Interconnections Replacing FlipChip Solder Assembly without Underfill  

E-Print Network [OSTI]

Reliability of Nano-Structured Nickel Interconnections Replacing FlipChip Solder Assembly without of Technology, GA 30332-0560 Abstract This paper reports the reliability of fine pitch interconnections using lower stresses in the interconnections and enhance reliability though they add electrical parasitics

Swaminathan, Madhavan

77

Statistical analysis of data from the solderability testing of electroless nickel plated Kovar leads  

SciTech Connect (OSTI)

Many Sandia National Laboratories components require electrical leads to be soldered to an assembly such as a printed wiring board. In late 1982, a supplier reported to Sandia that they had problems soldering leads of a 14/16 pin integrated circuit flatpack to printed wiring boards. These problems led to the investigation described herein of the fluxes used in solder-dipping. This study shows that Alpha 611 flux, used by the supplier, is not active enough to wet an electroless nickel-plated surface that has been exposed to 200C for 16 hours (which is a condition seen in production prior to soldering). Two Blackstone fluxes included in the study did provide uniform wetting in this situation and also for room temperature curing, even though the time in flux ranged from .25 to 10 minutes. Blackstone 642 flux had a higher wetting rate and lower contact angle than Blackstone 2508. However, Flux residues of B-642 contain chloride ions; therefore, B-2508 has now been adopted by the supplier.

Fisher, R.E.; Hall, I.J.

1986-01-01T23:59:59.000Z

78

Solidification pipes: from solder pots to igneous rocks M. Stewart Siua  

E-Print Network [OSTI]

Solidification pipes: from solder pots to igneous rocks M. Stewart Siua and Dmitry Budkerb resolidification. We use a simple model to describe the shape of the pipe and compare it with experimental results in volume of thallium during solidification. Such formation is sometimes known as "pipe" in metallurgy [2

Pines, Alexander

79

Reliability of Sn-3.5Ag Solder Joints in High Temperature Packaging Applications  

SciTech Connect (OSTI)

There is a significant need for next generation, high performance power electronic packages and systems with wide band gap devices to operate at high temperatures in automotive and electricity transmission applications. Sn-3.5Ag solder is a candidate for use in such packages with potential operating temperatures up to 200oC. However, there is a need to understand thermal cycling reliability of Sn-3.5Ag solders subject to such operating conditions. The results of a study on the damage evolution occurring in large area Sn-3.5Ag solders joints between silicon dies and DBC substrates subject to thermal cycling between 200oC and 5oC is presented in this paper. Damage accumulation was followed using high resolution X-ray radiography techniques while nonlinear finite element models were developed based on the mechanical property data available in literature to understand the relationship between the stress state within the solder joint and the damage evolution occurring under thermal cycling conditions. It was observed that regions of damage observed in the experiments do not correspond to the finite element predictions of the location of regions of maximum plastic work.

Muralidharan, Govindarajan [ORNL; Kurumaddali, Nalini Kanth [ORNL; Kercher, Andrew K [ORNL; Leslie, Dr Scott [Powerex Inc

2010-01-01T23:59:59.000Z

80

The Interaction Between an Imposed Current and the Creep of Idealized Sn-Ag-Cu Solder Interconnects  

E-Print Network [OSTI]

heating because prior thermal mapping of the joint done with an infrared (heating, the temperature of the solder joint was measured by attaching a thermocouple, and con?rmed by infrared

Kinney, Christopher; Lee, Tae-Kyu; Liu, Kuo-Chuan; Morris, J. W.

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

LCD, low-temperature soldering and compound semiconductor : the sources, market, applications and future prospects of indium in Malaysia  

E-Print Network [OSTI]

Indium is a minor but very valuable metal. Decreasing supplies of indium from refining and increasing demands from LCD, low-temperature soldering and compound semiconductors have stimulated the indium price increase ...

Yong, Foo Nun

2006-01-01T23:59:59.000Z

82

Determination of crystallographic orientation of lead-free piezoelectric (K,Na)NbO{sub 3} epitaxial thin films grown on SrTiO{sub 3} (100) surfaces  

SciTech Connect (OSTI)

Crystallographic structure of sol-gel-processed lead-free (K,Na)NbO{sub 3} (KNN) epitaxial films on [100]-cut SrTiO{sub 3} single-crystalline substrates was investigated for a deeper understanding of its piezoelectric response. Lattice parameter measurement by high-resolution X-ray diffraction and transmission electron microscopy revealed that the orthorhombic KNN films on SrTiO{sub 3} (100) surfaces are [010] oriented (b-axis-oriented) rather than commonly identified c-axis orientation. Based on the crystallographic orientation and corresponding ferroelectric domain structure investigated by piezoresponse force microscopy, the superior piezoelectric property along b-axis of epitaxial KNN films than other orientations can be explained.

Yu, Qi; Zhu, Fang-Yuan; Cheng, Li-Qian; Wang, Ke; Li, Jing-Feng, E-mail: jingfeng@mail.tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)] [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing (China)

2014-03-10T23:59:59.000Z

83

Spreading of Sn-Ag solders on FeNi alloys  

SciTech Connect (OSTI)

The spreading of Sn-3Ag-xBi solders on Fe-42Ni has been studied using a drop transfer setup. Initial spreading velocities as fast as {approx}0.5 m/s have been recorded. The results are consistent with a liquid front moving on a metastable, flat, unreacted substrate and can be described by using a modified molecular-kinetic model for which the rate controlling step is the movement of one atom from the liquid to the surface of the solid substrate. Although the phase diagram predicts the formation of two Fe-Sn intermetallics at the solder/substrate interface in samples heated at temperatures lower than 513 C, after spreading at 250 C only a thin FeSn reaction layer could be observed. Two interfacial layers (FeSn and FeSn2) were found after spreading at 450 C.

Saiz, Eduardo; Hwang, C-W.; Suganuma, Katsuaki; Tomsia, Antoni P.

2003-02-28T23:59:59.000Z

84

Process for reducing series resistance of solar cell metal contact systems with a soldering flux etchant  

DOE Patents [OSTI]

Disclosed is a process for substantially reducing the series resistance of a solar cell having a thick film metal contact assembly thereon while simultaneously removing oxide coatings from the surface of the assembly prior to applying solder therewith. The process includes applying a flux to the contact assembly and heating the cell for a period of time sufficient to substantially remove the series resistance associated with the assembly by etching the assembly with the flux while simultaneously removing metal oxides from said surface of said assembly.

Coyle, R. T. (Lakewood, CO); Barrett, Joy M. (Eldorado Springs, CO)

1984-01-01T23:59:59.000Z

85

Tin-Based Reactive Solders for Ceramic/Metal Joints RAKESH R. KAPOOR and THOMAS W . EAGAR  

E-Print Network [OSTI]

( { ) Tin-Based Reactive Solders for Ceramic/Metal Joints RAKESH R. KAPOOR and THOMAS W . EAGAR engine com- ponents), wear parts, tool materials, electrical feed- throughs, and metal contacts on ceramics. To overcome this problem, reactive metals are added to the filler metai.11- 181These reactive

Eagar, Thomas W.

86

Study of indium and solder bumps for the BTeV Pixel Detector  

SciTech Connect (OSTI)

The pixel detector proposed for the BTeV experiment at the Fermilab Tevatron will use bump-bonding technology based on either Indium or Pb/Sn solder to connect the front-end readout chips to the silicon pixel sensors. We have studied the strength of the bumps by visual inspection of the bumps bonding silicon sensor modules to dummy chips made out of glass. The studies were done before and after thermal cycles, exposed to intense irradiation, and with the assemblies glued to a graphite substrate. We have also carried out studies on effects of temperature changes on both types of bump bonds by observing the responses of single-chip pixel detectors to an Sr{sup 90} source. We report the results from these studies and our plan to measure the effect of cryogenic temperatures on the bumps.

Simon W Kwan et al.

2003-11-05T23:59:59.000Z

87

Effect of Thick Film Firing Conditions on the Solderability and Structure of Au-Pt-Pd Conductor for Low-Temperature, Co-Fired Ceramic Substrates  

SciTech Connect (OSTI)

Low-temperature, co-fired ceramics (LTCC) are the substrate material-of-choice for a growing number of multi-chip module (MCM) applications. Unlike the longer-standing hybrid microcircuit technology based upon alumina substrates, the manufacturability and reliability of thick film solder joints on LTCC substrates have not been widely studied. An investigation was undertaken to fully characterize such solder joints. A surface mount test vehicle with Daisy chain electrical connections was designed and built with Dupont{trademark} 951 tape. The Dupont{trademark} 4569 thick film ink (Au76-Pt21 -Pd3 wt.%) was used to establish the surface conductor pattern. The conductor pattern was fired onto the LTCC substrate in a matrix of process conditions that included: (1) double versus triple prints, (2) dielectric frame versus no frame, and (3) three firing temperatures (800 C, 875 C and 950 C). Pads were examined from the test vehicles. The porosity of the thick film layers was measured using quantitative image analysis in both the transverse and short transverse directions. A significant dependence on firing temperature was recorded for porosity. Solder paste comprised of Sn63-Pb37 powder with an RMA flux was screen printed onto the circuit boards. The appropriate components, which included chip capacitors of sizes 0805 up to 2225 and 50 mil pitch, leadless ceramic chip carriers having sizes of 16 I/O to 68 I/O, were then placed on the circuit boards. The test vehicles were oven reflowed under a N{sub 2} atmosphere. The solderability of the thick film pads was also observed to be sensitive to the firing conditions. Solderability appeared to degrade by the added processing steps needed for the triple print and dielectric window depositions. However, the primary factor in solderability was the firing temperature. Solderability was poorer when the firing temperature was higher.

Hernandez, C.L; Vianco, P.T.

1999-03-16T23:59:59.000Z

88

An evaluation of the spring finger solder joints on SA1358-10 and SA2052-4 connector assemblies (MC3617,W87).  

SciTech Connect (OSTI)

The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder joint used to attach the beryllium-copper (BeCu) spring fingers to the aluminum (Al) connector shell: (1) extended cracking within the fillet; (2) remelting of the solder joint during the follow-on, soldering step that attached the EMR adapter ring to the connector shell (and/or soldering the EMR shell to the adapter ring) that used the lower melting temperature 63Sn-37Pb (Sn-Pb) alloy; and (3) spalling of the Cd (Cr) layer overplating layer from the fillet surface. Several pedigrees of connectors were evaluated, which represented older fielded units as well as those assemblies that were recently constructed at Kansas City Plant. The solder joints were evaluated that were in place on connectors made with the current soldering process as well as an alternative induction soldering process for attaching the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely reflected the different extents to which the connector was mated to its counterpart assembly. In all cases, the spring finger solder joints on the SA1358-10 connectors were remelted as a result of the subsequent EMR adapter ring attachment process. Spalling of the Cd (Cr) overplating layer was also observed for these connectors, which was a consequence of the remelting activity. On the other hand, the SA2052-4 connector did not exhibit evidence of remelting of the spring finger solder joint. The Cd (Cr) layer did not show signs of spalling. These results suggested that, due to the size of the SA1358-10 connector, any of the former or current soldering processes used to attach the EMR adapter ring and/or EMR shell to the connector shell, requires a level of heat energy that will always result in the remelting of the spring finger solder joint attached with either the Sn-Ag or the Sn-Sb alloy. Lastly, it was construed that the induction soldering process, which is used to attach the EMR adapter ring onto the shell, was more likely to have caused the remelting event rather than the more localized heat source of the hand soldering iron used to attach the EMR shell to the adapter ring.

Kilgo, Alice C.; Vianco, Paul Thomas; Hlava, Paul Frank; Zender, Gary L.

2006-08-01T23:59:59.000Z

89

A new Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} based lead-free piezoelectric system with calculated end-member Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3}  

SciTech Connect (OSTI)

The phase structure, dielectric and piezoelectric properties of a new lead-free piezoelectric system (1???x)Bi{sub 0.5}Na{sub 0.5}TiO{sub 3}–xBi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} [(1???x)BNT–xBZH, x?=?0, 0.01, 0.02, 0.03, and 0.04] were investigated. The structure of Bi(Zn{sub 0.5}Hf{sub 0.5})O{sub 3} was calculated using first-principles method and (1???x)BNT–xBZH ceramics were fabricated by conventional solid-state process. At room temperature, a morphotropic phase boundary (MPB) from rhombohedral to pseudocubic is identified near x?=?0.02 by the analysis of X-ray diffraction patterns. The ceramics with MPB near room temperature exhibit excellent electrical properties: the Curie temperature, maximum polarization, remnant polarization, and coercive field are 340?°C, 56.3??C/cm{sup 2}, 43.5??C/cm{sup 2}, and 5.4?kV/mm, respectively, while the maximum positive bipolar strain and piezoelectric coefficient are 0.09% and 92 pC/N, respectively. In addition, a linear relationship between the MPB phase boundary composition and the calculated tetragonality of non-BNT end-member was demonstrated. Thus, this study not only shows a new BNT-based lead-free piezoelectric system but also suggest a new way to predict the composition at MPB a priori when designing new lead-free piezoelectric system.

Liu, Feng [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wahyudi, Olivia; Li, Yongxiang, E-mail: yxli@mail.sic.ac.cn [The Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China)

2014-03-21T23:59:59.000Z

90

Ames Lab 101: Technology Transfer  

ScienceCinema (OSTI)

Ames Laboratory Associate Laboratory Director, Sponsored Research Administration, Debra Covey discusses technology transfer. Covey also discusses Ames Laboratory's most successful transfer, lead-free solder.

Covey, Debra

2012-08-29T23:59:59.000Z

91

Ames Lab 101: Technology Transfer  

SciTech Connect (OSTI)

Ames Laboratory Associate Laboratory Director, Sponsored Research Administration, Debra Covey discusses technology transfer. Covey also discusses Ames Laboratory's most successful transfer, lead-free solder.

Covey, Debra

2010-01-01T23:59:59.000Z

92

Mechanical Behavior of Indium Nanostructures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Mechanical Behavior of Indium Nanostructures Mechanical Behavior of Indium Nanostructures Print Wednesday, 26 May 2010 00:00 Indium is a key material in lead-free solder...

93

Mechanical Behavior of Indium Nanostructures  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Mechanical Behavior of Indium Nanostructures Print Indium is a key material in lead-free solder applications for microelectronics due to its excellent wetting properties, extended...

94

Contributions Of Stress And Oxidation On The Formation Of Whiskers In Pb-Free Solders  

SciTech Connect (OSTI)

This report summarizes the research activities of WP-1754. The study focusses on the environmental factors influencing formation of lead free whiskers on electrodeposited tin coatings over copper (or copper containing) substrates. Much of the initial results are summarized in an interim report. From the initial results, two main areas were chosen to be the focus of additional research: the demonstration of effects of elastic stress state in the nucleation of whiskers and the confirmation of the effect of oxygen/nitrogen ratio in the formation of whiskers. Different levels of elastic stress were induced with the incorporation of a custom designed fixture that loaded the substrates in a four-point bending configuration and were maintained in an environmental chamber under conditions deemed favorable for whisker growth. The results show that induced elastic stress slightly increased the concentration of nucleation sites of whiskers. The effects of oxygen content were studied by aging substrates in gas vials of varying absolute pressure and different oxygen/nitrogen ratios. The concentration of whiskers were measured and appear to be sensitive to absolute pressure but are not sensitive to oxygen content (as previously observed).

Duncan, A. J.; Hoffman, E. N.

2014-03-25T23:59:59.000Z

95

Process for reducing series resistance of solar-cell metal-contact systems with a soldering-flux etchant  

DOE Patents [OSTI]

Disclosed is a process for substantially reducing the series resistance of a solar cell having a thick film metal contact assembly thereon while simultaneously removing oxide coatings from the surface of the assembly prior to applying solder therewith. The process includes applying a flux to the contact assembly and heating the cell for a period of time sufficient to substantially remove the series resistance associated with the assembly by etching the assembly with the flux while simultaneously removing metal oxides from said surface of said assembly.

Coyle, R.T.; Barrett, J.M.

1982-05-04T23:59:59.000Z

96

Growth of a Au-Ni-Sn intermetallic compound on the solder-substrate interface after aging  

SciTech Connect (OSTI)

Au/Ni metallization has become increasingly common in microelectronic packaging when Cu pads are joined with Pb-Sn solder. The outermost Au layer serves to protect the pad from corrosion and oxidation and the Ni layer provides a diffusion barrier to inhibit detrimental growth of Cu-Sn intermetallics. As a result of reflowing eutectic Pb-Sn on top of Au/Ni metallization, the as-solidified joints have AuSn{sub 4} precipitates distributed throughout the bulk of the solder joint, and Ni{sub 3}Sn{sub 4} intermetallics at the interface. Recent work has shown that the Au-Sn redeposits onto the interface during aging, compromising the strength of the joint. The present work shows that the redeposited intermetallic layer is a ternary compound with stoichiometry Au{sub 0.5}Ni{sub 0.5}Sn{sub 4}. The growth of this intermetallic layer was investigated, and results show that the ternary compound is observed to grow after as little as 3 hours at 150 C and after 3 weeks at 150 C has grown to a thickness of 10 {micro}m. Additionally, methods for inhibiting the growth of the ternary layer were investigated and it was determined that multiple reflows, both with and without additional aging can substantially limit the thickness of the ternary layer.

Minor, Andrew M.; Morris, J.W., Jr.

1999-12-16T23:59:59.000Z

97

Lead-free Thin Film Piezoelectric Devices - Energy Innovation Portal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE:1 First Use of Energy for All Purposes (Fuel and Nonfuel),Feet) Year Jan Feb Mar Apr MayAtmospheric Optical Depth7-1D: VegetationEquipment Surfaces and Interfaces Sample6, 2011 LawrenceE C H N I C A L TA L K

98

An analysis of lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.915}-(Bi{sub 0.5}K{sub 0.5}){sub 0.05}Ba{sub 0.02}Sr{sub 0.015}TiO{sub 3} ceramic for efficient refrigeration and thermal energy harvesting  

SciTech Connect (OSTI)

This article demonstrates the colossal energy harvesting capability of a lead-free (Bi{sub 0.5}Na{sub 0.5}){sub 0.915}-(Bi{sub 0.5}K{sub 0.5}){sub 0.05}Ba{sub 0.02}Sr{sub 0.015}TiO{sub 3} ceramic using the Olsen cycle. The maximum harvestable energy density estimated for this system is found to be 1523?J/L (1523?kJ/m{sup 3}) where the results are presented for extreme ambient conditions of 20–160?°C and electric fields of 0.1–4 MV/m. This estimated energy density is 1.7 times higher than the maximum reported to date for the lanthanum-doped lead zirconate titanate (thin film) system. Moreover, this study introduces a generalized and effective solid state refrigeration cycle in contrast to the ferroelectric Ericson refrigeration cycle. The cycle is based on a temperature induced polarization change on application of an unipolar electric field to ferroelectric ceramics.

Vats, Gaurav; Vaish, Rahul, E-mail: rahul@iitmandi.ac.in [School of Engineering, Indian Institute of Technology Mandi, Himachal Pradesh 175 001 (India); Bowen, Chris R. [Department of Mechanical Engineering, Materials Research Centre, University of Bath, Bath BA2 7AY (United Kingdom)

2014-01-07T23:59:59.000Z

99

Polar nanoregions and dielectric properties in high-strain lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-0.07BaTiO{sub 3} piezoelectric single crystals  

SciTech Connect (OSTI)

A structural coexistence of rhombohedral (R) and tetragonal (T) phases has been revealed in the (001){sub c}-cut lead-free 0.93(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}–0.07BaTiO{sub 3} (BNB7T) piezoelectric crystals, which grown by the self-flux method, in the lower temperatures by high-resolution synchrotron X-ray diffraction, reciprocal space mapping, and transmission electron microscopy. The dielectric permittivity exhibits a thermal hysteresis in the region of 120–260?°C, implying a first-order-like phase transition from R+T to T. The real part (??) of dielectric permittivity begins to deviates from the Curie-Weiss equation, ???=?C/(T ? T{sub o}), from the Burns temperature T{sub B}?=?460?°C, below which the polar nanoregions (or nanoclusters) develop and attenuate dielectric responses. The polar nanoregions of 5–10?nm were revealed by high-resolution transmission electron microscope. The normal piezoelectric coefficient d{sub 33} exhibits a rapid increase at E?=?15–20?kV/cm and reaches a maximum of d{sub 33} ?450 pC/N. The high piezoelectric response and E-field induced strain in BNB7T single crystals can be attributed to structural phase transitions under an E-field application.

Chen, Cheng-Sao, E-mail: rickchen@cc.hwh.edu.tw [Department of Mechanical Engineering, Hwa-Hsia Institute of Technology, New Taipei City 23567, Taiwan (China); Chen, Pin-Yi [Department of Mechanical Engineering, Ming-Chi University of Technology, New Taipei City 24301, Taiwan (China); Tu, Chi-Shun [Graduate Institute of Applied Science and Engineering, Fu Jen Catholic University, New Taipei City 24205, Taiwan (China)

2014-01-07T23:59:59.000Z

100

Effect of firing conditions on thick film microstructure and solder joint strength for low-temperature, co-fired ceramic substrates  

SciTech Connect (OSTI)

Low-temperature, co-fired ceramics (LTCC) are the substrate material-of-choice for a growing number of multi-chip module (MCM) applications. Unlike the longer-standing hybrid microcircuit technology based upon alumina substrates, the manufacturability and reliability of thick film solder joints on LTCC substrates have not been widely studied. An investigation was undertaken to fully characterize solder joints on these substrates. A surface mount test vehicle with Daisy chain electrical connections was designed and built with Dupont{trademark} 951 tape. The Dupont{trademark} 4569 thick film ink (Au76-Pt21-Pd3 wt.%) was used to establish the surface conductor pattern. The conductor pattern was fired onto the LTCC substrate in a matrix of processing conditions that included: (1) double versus triple prints, (2) dielectric window versus no window, and (3) three firing temperatures (800 C, 875 C and 950 C). Sn63-Pb37 solder paste with an RMA flux was screen printed onto the circuit boards. The appropriate packages, which included five sizes of chip capacitors and four sizes of leadless ceramic chip carriers, were placed on the circuit boards. The test vehicles were oven reflowed under a N{sub 2} atmosphere. Nonsoldered pads were removed from the test vehicles and the porosity of their thick film layers was measured using quantitative image analysis in both the transverse and short transverse directions. A significant dependence on firing temperature was recorded for porosity. The double printed substrates without a dielectric window revealed a thick film porosity of 31.2% at 800 C, 26.2% at 875 C and 20.4% at 950 C. In contrast, the thick film porosity of the triple printed substrates with a dielectric window is 24.1% at 800 C, 23.2% at 875 C and 17.6% at 950 C. These observations were compared with the shear strength of the as-fabricated chip capacitor solder joints to determine the effect of firing conditions on solder joint integrity. The denser films from the higher firing temperatures had correspondingly higher shear strengths. The 0805 chip capacitor had a shear strength of 12.6 {+-} 1.4 lbs. at 800 C, 13.3 {+-} 1.9 lbs. at 875 C and 13.6 {+-} 1.4 lbs. at 950 C for the triple printed substrates with a dielectric window. The trend was similar for the larger capacitors; the 1912's exhibiting shear strengths of 20.5 {+-} 4.8 lbs. at 800 C, 26.2 {+-} 1.7 lbs, at 875 C and 29.0 {+-} 0.2 lbs. at 950 C.

Hernandez, C.L.; Vianco, P.T.; Rejent, J.A.

2000-01-04T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

New Reliability Assessment Method for Solder Joints in BGA Package by Considering the Interaction between Design Factors  

E-Print Network [OSTI]

As the integration and the miniaturization of electronics devices, design space become narrower and interactions between design factors affect their reliability. This paper presents a methodology of quantifying the interaction of each design factor in electronics devices. Thermal fatigue reliability of BGA assembly was assessed with the consideration of the interaction between design factors. Sensitivity analysis shows the influence of each design factor to inelastic strain range of a solder joint characterizing the thermal fatigue life if no interaction occurs. However, there is the interaction in BGA assembly since inelastic strain range depends on not only a mismatch in CTE but also a warpage of components. Clustering can help engineers to clarify the relation between design factors. The variation in the influence was taken to quantify the interaction of each design factor. Based on the interaction, simple evaluating approach of inelastic strain range for the BGA assembly was also developed. BGA package was simplified into a homogeneous component and equivalent CTE wascalculated from the warpage of BGA and PCB. The estimated equation was derived by using the response surface method as a function of design factors. Based upon these analytical results, design engineers can rate each factor's effect on reliability and assess the reliability of their basic design plan at the concept design stage.

Satoshi Kondo; Qiang Yu; T. Shibutani; M. Shiratori

2008-01-07T23:59:59.000Z

102

Domain wall motion and electromechanical strain in lead-free piezoelectrics: Insight from the model system (1 ? x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} using in situ high-energy X-ray diffraction during application of electric fields  

SciTech Connect (OSTI)

The piezoelectric compositions (1 ? x)Ba(Zr{sub 0.2}Ti{sub 0.8})O{sub 3}–x(Ba{sub 0.7}Ca{sub 0.3})TiO{sub 3} (BZT-xBCT) span a model lead-free morphotropic phase boundary (MPB) between room temperature rhombohedral and tetragonal phases at approximately x?=?0.5. In the present work, in situ X-ray diffraction measurements during electric field application are used to elucidate the origin of electromechanical strain in several compositions spanning the tetragonal compositional range 0.6???x???0.9. As BCT concentration decreases towards the MPB, the tetragonal distortion (given by c/a-1) decreases concomitantly with an increase in 90° domain wall motion. The increase in observed macroscopic strain is predominantly attributed to the increased contribution from 90° domain wall motion. The results demonstrate that domain wall motion is a significant factor in achieving high strain and piezoelectric coefficients in lead-free polycrystalline piezoelectrics.

Tutuncu, Goknur [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Li, Binzhi [Department of Chemical Engineering and Materials Science, University of California, Davis, Davis, California 95616 (United States); Bowman, Keith [Illinois Institute of Technology, Armour College of Engineering, Chicago, Illinois 60616 (United States); School of Materials Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Jones, Jacob L., E-mail: JacobJones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-04-14T23:59:59.000Z

103

Gelatin based on Power-gel.TM. as solders for Cr4+laser tissue welding and sealing of lung air leak and fistulas in organs  

DOE Patents [OSTI]

Laser tissue welding can be achieved using tunable Cr4+ lasers, semiconductor lasers and fiber lasers, where the weld strength follows the absorption spectrum of water. The use of gelatin and esterified gelatin as solders in conjunction with laser inducted tissue welding impart much stronger tensile and torque strengths than albumin solders. Selected NIR wavelength from the above lasers can improve welding and avoid thermal injury to tissue when used alone or with gelatin and esterified gelatin solders. These discoveries can be used to enhance laser tissue welding of tissues such as skin, mucous, bone, blood vessel, nerve, brain, liver, pancreas, spleen, kidney, lung, bronchus, respiratory track, urinary tract, gastrointestinal tract, or gynecologic tract and as a sealant for pulmonary air leaks and fistulas such as intestinal, rectal and urinary fistulas.

Alfano, Robert R.; Tang, Jing; Evans, Jonathan M.; Ho, Peng Pei

2006-04-25T23:59:59.000Z

104

In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction  

SciTech Connect (OSTI)

Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the Beta-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of Beta-Sn derived from the electromigration data is in good agreement with the calculated value.

Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

2009-12-01T23:59:59.000Z

105

In situ measurement of electromigration-induced transient stress in Pb-free Sn-Cu solder joints by synchrotron radiation based X-ray polychromatic microdiffraction  

SciTech Connect (OSTI)

Electromigration-induced hydrostatic elastic stress in Pb-free SnCu solder joints was studied by in situ synchrotron X-ray white beam microdiffraction. The elastic stresses in two different grains with similar crystallographic orientation, one located at the anode end and the other at the cathode end, were analyzed based on the elastic anisotropy of the {beta}-Sn crystal structure. The stress in the grain at the cathode end remained constant except for temperature fluctuations, while the compressive stress in the grain at the anode end was built-up as a function of time during electromigration until a steady state was reached. The measured compressive stress gradient between the cathode and the anode is much larger than what is needed to initiate Sn whisker growth. The effective charge number of {beta}-Sn derived from the electromigration data is in good agreement with the calculated value.

Chen, Kai; Tamura, Nobumichi; Kunz, Martin; Tu, King-Ning; Lai, Yi-Shao

2009-05-15T23:59:59.000Z

106

An analysis of the pull strength behaviors of fine-pitch, flip chip solder interconnections using a Au-Pt-Pd thick film conductor on Low-Temperature, Co-fired Ceramic (LTCC) substrates.  

SciTech Connect (OSTI)

The assembly of the BDYE detector requires the attachment of sixteen silicon (Si) processor dice (eight on the top side; eight on the bottom side) onto a low-temperature, co-fired ceramic (LTCC) substrate using 63Sn-37Pb (wt.%, Sn-Pb) in a double-reflow soldering process (nitrogen). There are 132 solder joints per die. The bond pads were gold-platinum-palladium (71Au-26Pt-3Pd, wt.%) thick film layers fired onto the LTCC in a post-process sequence. The pull strength and failure modes provided the quality metrics for the Sn-Pb solder joints. Pull strengths were measured in both the as-fabricated condition and after exposure to thermal cycling (-55/125 C; 15 min hold times; 20 cycles). Extremely low pull strengths--referred to as the low pull strength phenomenon--were observed intermittently throughout the product build, resulting in added program costs, schedule delays, and a long-term reliability concern for the detector. There was no statistically significant correlation between the low pull strength phenomenon and (1) the LTCC 'sub-floor' lot; (2) grit blasting the LTCC surfaces prior to the post-process steps; (3) the post-process parameters; (4) the conductor pad height (thickness); (5) the dice soldering assembly sequence; or (5) the dice pull test sequence. Formation of an intermetallic compound (IMC)/LTCC interface caused by thick film consumption during either the soldering process or by solid-state IMC formation was not directly responsible for the low-strength phenomenon. Metallographic cross sections of solder joints from dice that exhibited the low pull strength behavior, revealed the presence of a reaction layer resulting from an interaction between Sn from the molten Sn-Pb and the glassy phase at the TKN/LTCC interface. The thick film porosity did not contribute, explicitly, to the occurrence of reaction layer. Rather, the process of printing the very thin conductor pads was too sensitive to minor thixotropic changes to ink, which resulted in inconsistent proportions of metal and glassy phase particles present during the subsequent firing process. The consequences were subtle, intermittent changes to the thick film microstructure that gave rise to the reaction layer and, thus, the low pull strength phenomenon. A mitigation strategy would be the use of physical vapor deposition (PVD) techniques to create thin film bond pads; this is multi-chip module, deposited (MCM-D) technology.

Uribe, Fernando R.; Kilgo, Alice C.; Grazier, John Mark; Vianco, Paul Thomas; Zender, Gary L.; Hlava, Paul Frank; Rejent, Jerome Andrew

2008-09-01T23:59:59.000Z

107

Tailoring of unipolar strain in lead-free piezoelectrics using the ceramic/ceramic composite approach  

SciTech Connect (OSTI)

The electric-field-induced strain response mechanism in a polycrystalline ceramic/ceramic composite of relaxor and ferroelectric materials has been studied using in situ high-energy x-ray diffraction. The addition of ferroelectric phase material in the relaxor matrix has produced a system where a small volume fraction behaves independently of the bulk under an applied electric field. Inter- and intra-grain models of the strain mechanism in the composite material consistent with the diffraction data have been proposed. The results show that such ceramic/ceramic composite microstructure has the potential for tailoring properties of future piezoelectric materials over a wider range than is possible in uniform compositions.

Khansur, Neamul H.; Daniels, John E. [School of Materials Science and Engineering, University of New South Wales, NSW 2052 (Australia); Groh, Claudia; Jo, Wook; Webber, Kyle G. [Institute of Materials Science, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Reinhard, Christina [Diamond Light Source, Beamline I12 JEEP, Didcot, Oxfordshire OX11 0DE (United Kingdom); Kimpton, Justin A. [The Australian Synchrotron, Clayton, Victoria 3168 (Australia)

2014-03-28T23:59:59.000Z

108

Investigation of Gold Nanoparticle Inks for Low-Temperature Lead-Free Packaging Technology  

E-Print Network [OSTI]

joint has excellent thermal stability and electromigration resistance, due to signi?cantly lower operating

Bakhishev, Teymur; Subramanian, Vivek

2009-01-01T23:59:59.000Z

109

Ferroelectric and octahedral tilt twin disorder and the lead-free piezoelectric, sodium potassium niobate system  

SciTech Connect (OSTI)

Using electron diffraction, trends in the local structural behaviour of the K{sub x}Na{sub 1-x}NbO{sub 3} (KNN x) 'solid solution' system are investigated and interpreted using an order/disorder based theoretical framework. At room temperature, electron diffraction shows a single plane of transverse polarised, diffuse intensity perpendicular to [0 1 0]{sub p} Low-Asterisk (p for parent sub-structure) across the entire phase diagram, indicative of ferroelectric disorder along the [0 1 0]{sub p} direction co-existing with long range ferroelectric order along the orthogonal [1 0 0]{sub p} and [0 0 1]{sub p} directions. An additional characteristic pattern of diffuse scattering is also observed, involving rods of diffuse intensity running along the [1 0 0]{sub p}* and [0 0 1]{sub p}* directions of the perovskite sub-structure and indicative of octahedral tilt disorder about the [1 0 0]{sub p} and [0 0 1]{sub p} axes co-existing with long range ordered octahedral tilting around the [0 1 0]{sub p} direction. A possible crystal chemical explanation for the existence of this latter octahedral tilt disorder is explored through bond valence sum calculations. The possible influence of both types of disorder on the previously refined, room temperature space group/s and average crystal structure/s is examined. - Graphical abstract: [-3,0.-1]p zone axis EDP of K{sub 0.46}Na{sub 0.54}NbO{sub 3} indexed according to both the relevant Pcm21 space groups (no subscripts) and the parent perovskite subcell (denoted by a subscript p). Highlights: Black-Right-Pointing-Pointer Characterises ferroelectric and octahedral tilt disorder in the KNN solid solution. Black-Right-Pointing-Pointer Discusses the possible driving forces for this disorder. Black-Right-Pointing-Pointer Discusses the implications of this disorder for physical properties. Black-Right-Pointing-Pointer Discusses the effects of this disorder on powder diffraction data.

Schiemer, Jason [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)] [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia); Withers, Ray L., E-mail: withers@rsc.anu.edu.au [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia); Liu, Yun; Yi, Zhiguo [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)] [Research School of Chemistry, The Australian National University, Canberra, ACT 0200 (Australia)

2012-11-15T23:59:59.000Z

110

Pull strength evaluation of Sn-Pb solder joints made to Au-Pt-Pd and Au thick film structures on low-temperature co-fired ceramic -final report for the MC4652 crypto-coded switch (W80).  

SciTech Connect (OSTI)

A study was performed that examined the microstructure and mechanical properties of 63Sn-37Pb (wt.%, Sn-Pb) solder joints made to thick film layers on low-temperature co-fired (LTCC) substrates. The thick film layers were combinations of the Dupont{trademark} 4596 (Au-Pt-Pd) conductor and Dupont{trademark} 5742 (Au) conductor, the latter having been deposited between the 4596 layer and LTCC substrate. Single (1x) and triple (3x) thicknesses of the 4596 layer were evaluated. Three footprint sizes were evaluated of the 5742 thick film. The solder joints exhibited excellent solderability of both the copper (Cu) lead and thick film surface. In all test sample configurations, the 5742 thick film prevented side wall cracking of the vias. The pull strengths were in the range of 3.4-4.0 lbs, which were only slightly lower than historical values for alumina (Al{sub 2}O{sub 3}) substrates. General (qualitative) observations: (a) The pull strength was maximized when the total number of thick film layers was between two and three. Fewer that two layers did not develop as strong of a bond at the thick film/LTCC interface; more than three layers and of increased footprint area, developed higher residual stresses at the thick film/LTCC interface and in the underlying LTCC material that weakened the joint. (b) Minimizing the area of the weaker 4596/LTCC interface (e.g., larger 5742 area) improved pull strength. Specific observations: (a) In the presence of vias and the need for the 3x 4596 thick film, the preferred 4596:5742 ratio was 1.0:0.5. (b) For those LTCC components that require the 3x 4596 layer, but do not have vias, it is preferred to refrain from using the 5742 layer. (c) In the absence of vias, the highest strength was realized with a 1x thick 5742 layer, a 1x thick 4596 layer, and a footprint ratio of 1.0:1.0.

Uribe, Fernando; Vianco, Paul Thomas; Zender, Gary L.

2006-06-01T23:59:59.000Z

111

Critical temperatures of superconducting solders  

E-Print Network [OSTI]

Different magnetic strengths in MRIs produce different reactions and provide more insight into what being imaged. Being able to more quickly switch between two or more different magnet strengths would allow scientists in ...

Pavćo, Erica Medeiros

2007-01-01T23:59:59.000Z

112

Response of intergrown microstructure to an electric field and its consequences in the lead-free piezoelectric bismuth sodium titanate  

SciTech Connect (OSTI)

We investigate the R3c average structure and micro-structure of the ceramic Bi{sub 0.5}Na{sub 0.5}TiO{sub 3} (BNT) in situ under applied electric fields using diffraction techniques. Electron diffraction implies the presence of significant octahedral tilt twin disorder, corresponding to the existence of a fine scale intergrown microstructural (IGMS) 'phase' within the R3c rhombohedral average structure matrix. A careful neutron refinement suggests not only that the off-centre displacements of the cations relative to the oxygens in the R3c regions increases systematically on application of an electric field but also that the phase fraction of the IGMS regions increases systematically. The latter change in phase fraction on application of the electric field enhances the polar displacement of the cations relative to the oxygen anions and affects the overall strain response. These IGMS regions form local polar nano regions that are not correlated with one another, resulting in polarisation relaxation and strain behaviour observed in BNT-containing materials. - Graphical abstract: The intergrown microstructure at very fine scales within the R3c rhombohedral phase matrix of BNT, originating from octahedral tilt twinning disorder, will increase with respect to an external field. Highlights: Black-Right-Pointing-Pointer The existence of an intergrown microstructural 'phase' within the average structure matrix. Black-Right-Pointing-Pointer This phase fraction of the intergrown microstructural regions changes. Black-Right-Pointing-Pointer Such regions form local polar nano regions that are not correlated with one another.

Liu Yun, E-mail: yliu@rsc.anu.edu.au [Research School of Chemistry, Australian National University, ACT 0200 (Australia); Noren, Lasse [Research School of Chemistry, the Australian National University, ACT 0200 (Australia); Studer, Andrew J. [Bragg Institute, Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC NSW 2232 (Australia); Withers, Ray L.; Guo Yiping [Research School of Chemistry, Australian National University, ACT 0200 (Australia); Li Yongxiang [State Key Laboratory of High Performance Ceramics and Superfine Microstructures, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050 (China); Yang Hui [Research School of Chemistry, Australian National University, ACT 0200 (Australia); College of Life Science and Technology, Shaanxi University of Science and Technology, Xian 710021 (China); Wang Jian [Research School of Chemistry, Australian National University, ACT 0200 (Australia)

2012-03-15T23:59:59.000Z

113

MASTER OF SCIENCE MECHANICAL ENGINEERING  

E-Print Network [OSTI]

and apparatus was developed and constructed based on a servo hydraulic test frame. The apparatus is capable, Lead Free Solder IMPROVED AEROTHERMODYNAMIC INSTRUMENTATION OF AN ALLISON T63-A-700 GAS TURBINE ENGINE for the gas generator turbine and exhaust state points were evaluated and average values were calculated

114

Dealing With Disaster: Surviving Misbehaved Kernel Extensions Margo I. Seltzer, Yasuhiro Endo, Christopher Small, Keith A. Smith  

E-Print Network [OSTI]

, Christopher Small, Keith A. Smith Harvard University Abstract Today's extensible operating systems allow

Brown, Angela Demke

115

AWS breaks new ground with soldering specification.  

SciTech Connect (OSTI)

Joining technologies continue to advance with new materials, process innovations, and inspection techniques. An increasing number of high-valued, high-reliability applications -- from boilers and ship hulls to rocket motors and medical devices -- have required the development of industry standards and specifications in order to ensure that the best design and manufacturing practices are being used to produce safe, durable products and assemblies. Standards writing has always had an important role at the American Welding Society (AWS). The AWS standards and specifications cover such topics as filler materials, joining processes, inspection techniques, and qualification methods that are used in welding and brazing technologies. These AWS standards and specifications, all of which are approved by the American National Standards Institute (ANSI), have also provided the basis for many similar documents used in Europe and in Pacific Rim countries.

Vianco, Paul Thomas

2008-08-01T23:59:59.000Z

116

E-Print Network 3.0 - arbuscular mycorrhizal roots Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

www.sciencenews.orgviewgenericid333224titlePlantsandfungirecognizegeneroustradingpartners Summary: a misbehaving helper. In the arbuscular mycorrhizal system though,...

117

Solder Joints of Power Electronics | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy Usage Ā» SearchEnergyDepartmentScoping Study |4 SolarPVSolar Viewed asat the10 DOE

118

Solder Joints of Power Electronics | Department of Energy  

Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Delicious RankCombustion |Energy Usage Ā» SearchEnergyDepartmentScoping Study |4 SolarPVSolar Viewed asat the10 DOE09

119

Research into the microstructure and mechanical behavior of eutectic Bi-Sn and In-Sn  

SciTech Connect (OSTI)

This manuscript reports on research into two low-melting, lead-free solder alloys, eutectic Bi-Sn and eutectic In-Sn. The microstructures were found to depend on both cooling rate and substrate, with the greatest variability in the In-Sn alloy. The nature of the intermetallic layer formed at the solder-substrate interface depends on both the solder and the substrate (Cu versus Ni). Also, the microstructure of the Bi-Sn can recrystallize during deformation, which is not the case with In-Sn. Data from creep and constant strain rate tests are given for slowly cooled samples. The creep behavior of In-Sn is constant with temperature, but the creep seems to be controlled by the In-rich phase in In-Sn on Cu and by the Sn-rich phase in In-Sn on Ni. Bi-Sn exhibits different creep behavior at temperatures above 40 {degrees}C than at 20 {degrees}C or lower. Stress-strain curves of Bi-Sn on Cu and In-Sn on Cu are similar, while In-Sn on Ni behaves differently. This is explained in terms of the deformation patterns in the alloys.

Goldstein, J.L.F.; Mei, Z.; Morris, J.W. Jr. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1993-08-01T23:59:59.000Z

120

E-Print Network 3.0 - allogeneic split-skin grafting Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

With Disaster: Surviving Misbehaved Kernel Extensions Margo I. Seltzer, Yasuhiro Endo, Christopher Small, Keith A. Smith Summary: of application extensions, or grafts, into the...

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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121

Impacts of Cooling Technology on Solder Fatigue for Power Modules in Electric Traction Drive Vehicles: Preprint  

SciTech Connect (OSTI)

Describes three power module cooling topologies for electric traction drive vehicles: two advanced options using jet impingement cooling and one option using pin-fin liquid cooling.

O'Keefe, M.; Vlahinos, A.

2009-08-01T23:59:59.000Z

122

Comparison of Accelerated Testing with Modeling to Predict Lifetime of CPV Solder Layers (Presentation)  

SciTech Connect (OSTI)

Concentrating photovoltaic (CPV) cell assemblies can fail due to thermomechanical fatigue in the die-attach layer. In this presentation, we show the latest results from our computational model of thermomechanical fatigue. The model is used to estimate the relative lifetime of cell assemblies exposed to various temperature histories consistent with service and with accelerated testing. We also present early results from thermal cycling experiments designed to help validate the computational model.

Silverman, T. J.; Bosco, N.; Kurtz, S.

2012-03-01T23:59:59.000Z

123

Contractual Anonymity Edward J. Schwartz David Brumley  

E-Print Network [OSTI]

will remain anonymous and indistinguishable as long as they abide by a pre-negotiated terms of service contract, 2) network providers can identify users who misbehave by violating the same contract, and 3

124

Rework of CSP: the effect on surface intermetallic Electronics Manufacturing Research Group, School of Aeronautical, Mechanical  

E-Print Network [OSTI]

solder joint formed on a copper pad with electroless nickel/immersion gold coatings consists solderable layer (nickel); 3 a single intermetallic layer (Ni3Sn4); 4 bulk solder region (Sn-Pb). This paper

Ekere, Ndy

125

JOURNAL OF MICROELECTROMECHANICAL SYSTEMS, VOL. 10, NO. 1, MARCH 2001 107 Fabrication of Metallic Heat Exchangers Using  

E-Print Network [OSTI]

­ silicon etching, titanium diffusion bonding, tin/lead soldering, and micromachining of copper ­ commonly

Prentiss, Mara

126

Understanding and predicting metallic whisker growth and its effects on reliability : LDRD final report.  

SciTech Connect (OSTI)

Tin (Sn) whiskers are conductive Sn filaments that grow from Sn-plated surfaces, such as surface finishes on electronic packages. The phenomenon of Sn whiskering has become a concern in recent years due to requirements for lead (Pb)-free soldering and surface finishes in commercial electronics. Pure Sn finishes are more prone to whisker growth than their Sn-Pb counterparts and high profile failures due to whisker formation (causing short circuits) in space applications have been documented. At Sandia, Sn whiskers are of interest due to increased use of Pb-free commercial off-the-shelf (COTS) parts and possible future requirements for Pb-free solders and surface finishes in high-reliability microelectronics. Lead-free solders and surface finishes are currently being used or considered for several Sandia applications. Despite the long history of Sn whisker research and the recently renewed interest in this topic, a comprehensive understanding of whisker growth remains elusive. This report describes recent research on characterization of Sn whiskers with the aim of understanding the underlying whisker growth mechanism(s). The report is divided into four sections and an Appendix. In Section 1, the Sn plating process is summarized. Specifically, the Sn plating parameters that were successful in producing samples with whiskers will be reviewed. In Section 2, the scanning electron microscopy (SEM) of Sn whiskers and time-lapse SEM studies of whisker growth will be discussed. This discussion includes the characterization of straight as well as kinked whiskers. In Section 3, a detailed discussion is given of SEM/EBSD (electron backscatter diffraction) techniques developed to determine the crystallography of Sn whiskers. In Section 4, these SEM/EBSD methods are employed to determine the crystallography of Sn whiskers, with a statistically significant number of whiskers analyzed. This is the largest study of Sn whisker crystallography ever reported. This section includes a review of previous literature on Sn whisker crystallography. The overall texture of the Sn films was also analyzed by EBSD. Finally, a short Appendix is included at the end of this report, in which the X-Ray diffraction (XRD) results are discussed and compared to the EBSD analyses of the overall textures of the Sn films. Sections 2, 3, and 4 have been or will be submitted as stand-alone papers in peer-reviewed technical journals. A bibliography of recent Sandia Sn whisker publications and presentations is included at the end of the report.

Michael, Joseph Richard; Grant, Richard P.; Rodriguez, Mark Andrew; Pillars, Jamin; Susan, Donald Francis; McKenzie, Bonnie Beth; Yelton, William Graham

2012-01-01T23:59:59.000Z

127

On Data-centric Misbehavior Detection in VANETs Sushmita Ruj, Marcos A. Cavenaghi, Zhen Huang, Amiya Nayak, and Ivan Stojmenovic  

E-Print Network [OSTI]

and propose algorithms which detect false alert messages and misbehaving nodes by observing their actions). Malicious nodes might have criminal motives to cause accidents and may also attempt to gather sensitive together. Authentication techniques rely on signatures, a message is signed with a private key to verify

Stojmenovic, Ivan

128

E-Print Network 3.0 - advanced development model Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Office of Biorenewables Programs Collection: Renewable Energy 66 Kompetenzzentrum fr Automobil-und Industrieelektronik Summary: Interconnect technology: Diffusion soldering...

129

A computer music instrumentarium  

E-Print Network [OSTI]

Chapter 6. COMPUTERS: To Solder or Not toMusic Models : A Computer Music Instrumentarium . . . . .Interactive Computer Systems . . . . . . . . . . . . . . 101

Oliver La Rosa, Jaime Eduardo

2011-01-01T23:59:59.000Z

130

Closeout Report for theCloseout Report for the National Spherical Torus  

E-Print Network [OSTI]

in recommendations to improve techniques for soldering cooling tubes in the TF conductor to prevent flux from techniques (e.

Princeton Plasma Physics Laboratory

131

Chapter 5: Ball Grid Array (BGA) 5.1 Development of the Models  

E-Print Network [OSTI]

of these is left to a future sub-model of the solder joints. The top and bottom layers of each ball are 25 micron #12;Thirdly, the unit cell is replicated to form a block of 34 solder balls, which represents one Results The predicted lifetime of each model is based on the strain development within the solder joints

Berlin,Technische UniversitƤt

132

Multiwire conductor having greatly increased interwire resistance and method for making same  

DOE Patents [OSTI]

An improved multiwire conductor of the type which is mechanically stabilized by a tin based solder filler is described. A solder filled conductor is heated to a temperature above its melting point for a period long enough to allow a substantial amount of copper to be dissolved from the wires comprising the conductor. The copper forms the brittle intermetallic compound Cu/sub 5/Sn/sub 6/ with tin in the solder. After cooling the conductor is flexed causing a random cracking of the solder, and thereby increasing the interwire resistance of the conductor. The subject invention is particularly adapted for use with braided, ribbon-type solder filled superconductors.

Luhman, T.; Suenaga, M.

1982-03-15T23:59:59.000Z

133

Knowledge based process planning system for electronic assembly  

E-Print Network [OSTI]

. In both cases the connection is made permanent by soldering the leads. The two methods require different component geometries, assembly machines and soldering methods. Of these, surface mount method is a relatively new technology and is becoming... of solder paste or adhesives, cleaning processes, material handling, inspection and testing Operations [11, 12, 13]. Assembly Operations are concerned with the delivery of components to a specified location on the board. Assembly Operations can...

Sabapathy, Arvindh

2012-06-07T23:59:59.000Z

134

E-Print Network 3.0 - accidental flap complication Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

methods have been proposed for surface micromachined flaps. The structures can... and surface tension of wet solder 4 have been used to lift and permanently assemble ......

135

Thermal Effects on PCB Laminate Material Dielectric Constant and Dissipation Scott Hinaga  

E-Print Network [OSTI]

will be exposed to a higher temperature (250-260Ā°C), if Hot Air Solder Level (HASL) surface finish is applied

Koledintseva, Marina Y.

136

Identifying Local Minima in the Liquidus Surface Using the FactSage ...  

E-Print Network [OSTI]

as amorphous alloys or solders for metallic systems, and electrical batteries or thermal energy storage for salt systems. The experimental determination of low ...

Sebastien Le Digabel

2010-12-21T23:59:59.000Z

137

For Immediate Release --Friday, May 10, 2013 Discovery Day brings science to life for Canada-Wide  

E-Print Network [OSTI]

and the Human Body Alberta Water and Environmental Science Building Interactive Tour - Soldering and Circuit Boards Water Watch Ā­ Monitoring Pollution in Our Water

Seldin, Jonathan P.

138

In: O'Brien R L (ed.) Welding Handbook-Volume 3: Materials and Applications, 8th Edn. American Welding  

E-Print Network [OSTI]

(fastening, adhesive bonding, soldering, brazing, arc welding, diffusion bonding, resistance welding, etc, such as diffusion bonding, come very close to this ideal; .·. ·.'· .. . . . : ' : \\. ·:-';..·. .: ... Joining

Eagar, Thomas W.

139

The Global Anthropogenic Lead Experiment Earth, Atmospheric and Planetary Sciences  

E-Print Network [OSTI]

, coal combustion, incineration, cement manufacture). Ā· Leaded gasoline utilization creates fine activities (smelting, coal burning, etc.) Ā· Incineration -------------------------- Ā· "Tin" can solder seams

Einat, Aharonov

140

DOE/LX/07-0087&D1 Secondary Document DMSA C-333-41 Solid Waste...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

included welding rods, solder, a Nissen metal marker, fluorescent light starters, incandescent light bulbs and ends, fluorescent light bulb ends, miscellaneous lead pieces, and...

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

DOE/LX/07-0085&D1 Secondary Document DMSA C-331-16 Solid Waste...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

an aerosol can, and a bottle of Ruby Fluid Soldering Flux. Newly generated RCRA hazardous waste removed included light bulbs, fuses, circuit boards, vacuum tubes, mercury...

142

Microsoft Word - SWMU 214 OS-03 rev 121407 - draft.doc  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

fuses, manometer, solder, epoxy, and light bulbs. Newly generated RCRA regulated hazardous wastes removed included light bulb, fuses, circuit boards, and waste oils. The Toxic...

143

ANALYSIS OF CATASTROPHIC FIELD FAILURES DUE TO CONDUCTIVE ANODIC FILAMENT (CAF) FORMATION  

E-Print Network [OSTI]

in the use environment. CAF formation is enhanced by the use of certain hot air solder leveling (HASL) fluids failures were related to boards produced in a manufacturing process, which included HASL. One CAF failure-ray spectroscopy (EDS) and ion chromatography (IC) will be used to relate the hot air solder leveling (HASL) fluid

Bennett, Gisele

144

This is an author-deposited version published in: http://oatao.univ-toulouse.fr/ Eprints ID: 10622  

E-Print Network [OSTI]

diffusion bonding (SSDB) are now cited as substitutes for solders reflow process. Particularly, solid state diffusion bonding [3,4] is used for silver and gold based alloys such as Au-Sn and Au-Ge solders of voids or weak intermetallic compounds in the interfaces. There are many ways to en- sure good bonding

Paris-Sud XI, Université de

145

DOI: 10.1002/adma.200601787 Microsolidics: Fabrication of Three-Dimensional Metallic  

E-Print Network [OSTI]

.[18] The technique has also been used to form 3D connec- tions (e.g., bridging opposite sides approaches to bridge electrical "islands" of metal by heating solid rods of solder "on chip"--the solder oxide semiconductor field-effect transistors,[26] and flexible gold­polymer nano- composites as passive

Prentiss, Mara

146

Phase-field Models for Solidification and Solid/Liquid Interactions  

E-Print Network [OSTI]

and discussions . . . . . . . . . . . . . . . . . 102 E. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . 111 V MULTIPHASE FIELD SIMULATIONS OF INTERMETAL- LIC COMPOUND GROWTH DURING SOLDERING RE- ACTIONS... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 A. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 113 B. Intermetallic compound growth during soldering reac- tion for Cu6Sn5 . . . . . . . . . . . . . . . . . . . . . . . . 115 1. Phase ?eld and di?usion equations...

Park, Min Soo

2011-02-22T23:59:59.000Z

147

This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 8792  

E-Print Network [OSTI]

and Raynaud, Lidwine Silver oxalate-based solders: New materials for high thermal conductivity microjoining oxalate-based solders: New materials for high thermal conductivity microjoining K. Kiryukhina,a,b,c,d H low pressure (thermal conductivity close to 100 W mĆ?1 KĆ?1 , making silver

Mailhes, Corinne

148

This is an author-deposited version published in : http://oatao.univ-toulouse.fr/ Eprints ID : 8792  

E-Print Network [OSTI]

and Raynaud, Lidwine Silver oxalate-based solders: New materials for high thermal conductivity microjoining processed at 300 Ā°C and very low pressure (thermal conductivity close to 100 W mĆ?1 KĆ?1 : 10.1016/j.scriptamat.2012.12.018 #12;Silver oxalate-based solders: New materials for high thermal

Paris-Sud XI, UniversitƩ de

149

NCMS PWB Surface Finishes Team project summary  

SciTech Connect (OSTI)

The NCMS PWB Surface Finishes Consortium is just about at the end of the five year program. Dozens of projects related to surface finishes and PWB solder-ability were performed by the team throughout the program, and many of them are listed in this paper. They are listed with a cross reference to where and when a technical paper was presented describing the results of the research. However, due to time and space constraints, this paper can summarize the details of only three of the major research projects accomplished by the team. The first project described is an ``Evaluation of PWB Surface Finishes.`` It describes the solderability, reliability, and wire bondability of numerous surface finishes. The second project outlined is an ``Evaluation of PWB Solderability Test Methods.`` The third project outlined is the ``Development and Evaluation of Organic Solderability Preservatives.``

Kokas, J.; DeSantis, C. [United Technologies Corp., Farmington, CT (United States). Hamilton Standard Div.; Wenger, G. [AT and T, New York, NY (United States)] [and others

1996-04-01T23:59:59.000Z

150

E-Print Network 3.0 - aqueous reprocessing system Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(GLODAP) Collection: Environmental Sciences and Ecology 11 Proceedings of the 2007 Aging Aircraft Conference Cost Model for Assessing the Transition to Lead-Free Electronics...

151

Improved generator and detector of millimeter waves for use in microwave spectroscopy  

E-Print Network [OSTI]

of the corrosion problem were necessary. Tungsten wire was nickel plated and soldered in place. A pair of probes having solidered connections between tungsten and brass was made and tested. Not only were they appreciably more efficient in energy output.... It was necessary to solder small pieces of the slabs to the crystal mounting block and to grind them to the proper size for use as detector and generator crystals. Silicon semiconductor must first be nickel plated before it can be soldered. The nickel plating...

Tolberg, Wesley Edward

1958-01-01T23:59:59.000Z

152

Hazardous material minimization for radar assembly. Final report  

SciTech Connect (OSTI)

The Clean Air Act Amendment, enacted in November 1990, empowered the Environmental Protection Agency (EPA) to completely eliminate the production and usage of chlorofluorocarbons (CFCs) by January 2000. A reduction schedule for methyl chloroform beginning in 1993 with complete elimination by January 2002 was also mandated. In order to meet the mandates, the processes, equipment, and materials used to solder and clean electronic assemblies were investigated. A vapor-containing cleaning system was developed. The system can be used with trichloroethylene or d-Limonene. The solvent can be collected for recycling if desired. Fluxless and no-clean soldering were investigated, and the variables for a laser soldering process were identified.

Biggs, P.M.

1997-03-01T23:59:59.000Z

153

Methods of making metallic glass foil laminate composites  

DOE Patents [OSTI]

A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone. 6 figs.

Vianco, P.T.; Fisher, R.W.; Hosking, F.M.; Zanner, F.J.

1996-08-20T23:59:59.000Z

154

Methods of making metallic glass foil laminate composites  

DOE Patents [OSTI]

A process for the fabrication of a rapidly solidified foil laminate composite. An amorphous metallic glass foil is flux treated and coated with solder. Before solidification of the solder the foil is collected on a take-up spool which forms the composite into a solid annular configuration. The resulting composite exhibits high strength, resiliency and favorable magnetic and electrical properties associated with amorphous materials. The composite also exhibits bonding strength between the foil layers which significantly exceeds the bulk strength of the solder alone.

Vianco, Paul T. (Albuquerque, NM); Fisher, Robert W. (Albuquerque, NM); Hosking, Floyd M. (Albuquerque, NM); Zanner, Frank J. (Sandia Park, NM)

1996-01-01T23:59:59.000Z

155

Low-temperature hermetic sealing of optical fiber components  

DOE Patents [OSTI]

A method for manufacturing low-temperature hermetically sealed optical fi components is provided. The method comprises the steps of: inserting an optical fiber into a housing, the optical fiber having a glass core, a glass cladding and a protective buffer layer disposed around the core and cladding; heating the housing to a predetermined temperature, the predetermined temperature being below a melting point for the protective buffer layer and above a melting point of a solder; placing the solder in communication with the heated housing to allow the solder to form an eutectic and thereby fill a gap between the interior of the housing and the optical fiber; and cooling the housing to allow the solder to form a hermetic compression seal between the housing and the optical fiber.

Kramer, Daniel P. (Centerville, OH)

1996-10-22T23:59:59.000Z

156

DOE Publishes Report on Accelerated Life Testing of SSL Luminaires...  

Broader source: Energy.gov (indexed) [DOE]

of which were attributed to solder-joint fatigue, and the other two to board-level corrosion. The findings reinforce the belief that LEDs in lighting systems are highly...

157

Non-contact biopotential sensing  

E-Print Network [OSTI]

hot air surface leveled (HASL) PCB finish, silver cloth,electrodes for BSNs. The HASL PCB finish and solder mask areAg/AgCl electrode, cotton, HASL, latex, silver cloth, and

Chi, Yu Mike

2011-01-01T23:59:59.000Z

158

IEEE TRANSACTIONS ON ADVANCED PACKAGING, VOL. 23, NO. 2, MAY 2000 285 A Comparison of Hourly Versus Daily  

E-Print Network [OSTI]

leveling (HASL) fluids. This work evaluates two electrical reliability-testing methods. One method recorded, hot-air solder leveling (HASL) fluids, surface insulation resistance (SIR), water-soluble flux. I

Bennett, Gisele

159

Identification of time-dependent interfacial mechanical properties of adhesive by hybrid/inverse method  

E-Print Network [OSTI]

dissimilar as well as similar mate- rials including metals, plastics, elastomers, glass, ceramics and wood, screwing, welding and soldering are (1) relative uniform stress distribution; (2) ability to bond

Qin, Qinghua

160

E-Print Network 3.0 - application au common Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Italy, 26-28 April 2006 AU-SN FLIP-CHIP SOLDER BUMP FOR MICROELECTRONIC AND OPTOELECTRONIC... APPLICATIONS Jeong-Won Yoon, Hyun-Suk Chun, Ja-Myeong Koo and Seung-Boo Jung...

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

E-Print Network 3.0 - application au complexe Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Italy, 26-28 April 2006 AU-SN FLIP-CHIP SOLDER BUMP FOR MICROELECTRONIC AND OPTOELECTRONIC... APPLICATIONS Jeong-Won Yoon, Hyun-Suk Chun, Ja-Myeong Koo and Seung-Boo Jung...

162

E-Print Network 3.0 - activated au foils Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

eutectic alloy formation by Si implantation in polycrystalline Au Summary: foils (35 lm thick) to form a low melting point AuSi alloy which can be used for gold soldering. A...

163

CUTTING -WELDING -HOT WORKS REQUIRED NOTIFICATION TO CUFD  

E-Print Network [OSTI]

CUTTING - WELDING - HOT WORKS REQUIRED NOTIFICATION TO CUFD Instructions: Fill out this form in its Time for work: Description of Work: Brazing Roofing Sweating WeldingSolderingCutting Other

Stuart, Steven J.

164

OPERATIONAL PERFORMANCES DEMONSTRATION OF POLYMER-CERAMIC EMBEDDED CAPACITORS FOR MMIC APPLICATIONS  

E-Print Network [OSTI]

coefficient and the thermal conductivity between the ceramic dielectric, the terminations, the solderOPERATIONAL PERFORMANCES DEMONSTRATION OF POLYMER- CERAMIC EMBEDDED CAPACITORS FOR MMIC candidates for dielectric materials applied for embedded passives are polymer- ceramic nanocomposites

Boyer, Edmond

165

Pressure activated diaphragm bonder  

DOE Patents [OSTI]

A device is available for bonding one component to another, particularly for bonding electronic components of integrated circuits, such as chips, to a substrate. The bonder device in one embodiment includes a bottom metal block having a machined opening wherein a substrate is located, a template having machined openings which match solder patterns on the substrate, a thin diaphragm placed over the template after the chips have been positioned in the openings therein, and a top metal block positioned over the diaphragm and secured to the bottom block, with the diaphragm retained therebetween. The top block includes a countersink portion which extends over at least the area of the template and an opening through which a high pressure inert gas is supplied to exert uniform pressure distribution over the diaphragm to keep the chips in place during soldering. A heating means is provided to melt the solder patterns on the substrate and thereby solder the chips thereto. 4 figs.

Evans, L.B.; Malba, V.

1997-05-27T23:59:59.000Z

166

Towards Energy and Resource Efficient Manufacturing: A Processes and Systems Approach  

E-Print Network [OSTI]

Processes and Equip- ment. 9th Global Conference on Sustainablein Cutting Processes. 9th Global Conference on Sustainableand Sustainable Energy Reviews [171] Saiganesh S, Sekulic DP (2010) Balancing Material and Exergy Flows for a PCB Soldering process:

2012-01-01T23:59:59.000Z

167

XINGHUI LIU 1111 Engineering Drive, UCB 427, Boulder, Colorado 80309-0427  

E-Print Network [OSTI]

: machining, mold & die, 3D printing, PCB, soldering and etc. (~2 years hands-on experience) Programming atomization system to produce an ultra-fine metal powers. ---- NSF in China 3D printing with laser sintering

Bunch, Scott

168

Spectral characteristics of a laser emitter designed for pumping and detecting a reference quantum transition of a caesium frequency standard  

SciTech Connect (OSTI)

Experimental and calculated spectral characteristics of a diode laser with a Bragg grating soldered on a thermoelectric cooler are presented. A model of the laser is developed, which takes into account the pressure arising after soldering the Bragg grating on the thermoelectric cooler, as well as temperature and dispersion. Theoretical and experimental spectral characteristics of the laser are compared and their satisfactory agreement is shown. (control of radiation parameters)

Ivanov, A V; Kurnosov, V D; Kurnosov, K V; Romantsevich, V I; Chernov, Roman V; Marmalyuk, Aleksandr A; Volkov, N A; Zholnerov, V S

2011-08-31T23:59:59.000Z

169

Fluorination of the cyanogen halides  

E-Print Network [OSTI]

silver has a coordination number of 12 two, one might speculate that a coordination compound la formed with a silver fluoride on both ends of the cyanogen todlde molecule. This arrangement would satisfy one silver with a fluoride and a cyanide... copper caps which were sliver soldered ln place. Copper tubing entrance and exit tubes were silver soldered to the top of the pot. The pipe union formed a leak proof system which could be assembled with reactants, and disassembled after reaction...

Ward, Raymond Anthony

1960-01-01T23:59:59.000Z

170

Petroleum Refining Energy Use in Relation to Fuel Products Made  

E-Print Network [OSTI]

In recent years crude oils available to refiners have required more energy to refine and refiners have adjusted their processes to obtain better energy efficiency. In addition, the shift to lead-free gasoline has led to refining adjustments...

White, J. R.; Marshall, J. F.; Shoemaker, G. L.; Smith, R. B.

1983-01-01T23:59:59.000Z

171

Ceramic-polymer nanocomposites with increased dielectric permittivity and low dielectric loss  

SciTech Connect (OSTI)

The use of lead free materials in device fabrication is very essential from environmental point of view. We have synthesized the lead free ferroelectric polymer nanocomposite films with increased dielectric properties. Lead free bismuth titanate has been used as active ceramic nanofillers having crystallite size 24nm and PVDF as the polymer matrix. Ferroelectric ?-phase of the polymer composite films was confirmed by X-ray diffraction pattern. Mapping data confirms the homogeneous dispersion of ceramic particles into the polymer matrix. Frequency dependent dielectric constant increases up to 43.4 at 100Hz, whereas dielectric loss decreases with 7 wt% bismuth titanate loading. This high dielectric constant lead free ferroelectric polymer films can be used for energy density applications.

Bhardwaj, Sumit, E-mail: sumit.bhardwaj4@gmail.com; Paul, Joginder, E-mail: sumit.bhardwaj4@gmail.com [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Raina, K. K. [School of Physics and Materials Science, Thapar University, Patiala -147 004 (India); Thakur, N. S. [Centre for Energy and Environment, National Institute of Technology, Hamirpur -177005 (India); Kumar, Ravi [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Beant College of Engineering and Technology, Gurdaspur -143521 (India)

2014-04-24T23:59:59.000Z

172

Cisco Systems Funds "Whisker" Growth Research at the ALS  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Cisco Systems Funds "Whisker" Growth Research at the ALS Cisco Systems Funds "Whisker" Growth Research at the ALS Print Friday, 09 November 2012 10:06 Lead-free components have...

173

Current Lead Design for the Accelerator Project for Upgrade of LHC  

SciTech Connect (OSTI)

The Accelerator Project for Upgrade of LHC (APUL) is a U.S. project participating in and contributing to CERN's Large Hadron Collider (LHC) upgrade program. In collaboration with Brookhaven National Laboratory, Fermilab is developing sub-systems for an upgrade of the LHC final focus magnet systems. A concept of main and auxiliary helium flow was developed that allows the superconductor to remain cold while the lead body warms up to prevent upper section frosting. The auxiliary flow will subsequently cool the thermal shields of the feed box and the transmission line cryostats. A thermal analysis of the current lead central heat exchange section was performed using analytic and FEA techniques. A method of remote soldering was developed that allows the current leads to be field replaceable. The remote solder joint was designed to be made without flux or additional solder, and able to be remade up to ten full cycles. A method of upper section attachment was developed that allows high pressure sealing of the helium volume. Test fixtures for both remote soldering and upper section attachment for the 13 kA lead were produced. The cooling concept, thermal analyses, and test results from both remote soldering and upper section attachment fixtures are presented.

Brandt, Jeffrey S.; Cheban, Sergey; Feher, Sandor; Kaducak, Marc; Nobrega, Fred; Peterson, Tom

2010-01-01T23:59:59.000Z

174

Solar cell array interconnects  

DOE Patents [OSTI]

Electrical interconnects are disclosed for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb-Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb-Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value. 4 figs.

Carey, P.G.; Thompson, J.B.; Colella, N.J.; Williams, K.A.

1995-11-14T23:59:59.000Z

175

Method of assembling an electric power  

DOE Patents [OSTI]

A method of assembling and providing an electric power apparatus. The method uses a heat resistant housing having a structure adapted to accommodate and retain a power circuit card and also including a bracket adapted to accommodate and constrain a rigid conductive member. A power circuit card having an electrical terminal is placed into the housing and a rigid conductive member into the bracket. The rigid conductive member is flow soldered to the electrical terminal, thereby exposing the heat resistant housing to heat and creating a solder bond. Finally, the rigid conductive member is affirmatively connected to the housing. The bracket constrains the rigid conductive member so that the act of affirmatively connecting does not weaken the solder bond.

Rinehart, Lawrence E. (Lake Oswego, OR); Romero, Guillermo L. (Phoenix, AZ)

2007-05-03T23:59:59.000Z

176

Solar cell array interconnects  

DOE Patents [OSTI]

Electrical interconnects for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb-Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb-Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value.

Carey, Paul G. (Mountain View, CA); Thompson, Jesse B. (Brentwood, CA); Colella, Nicolas J. (Livermore, CA); Williams, Kenneth A. (Livermore, CA)

1995-01-01T23:59:59.000Z

177

Process for electrically interconnecting electrodes  

DOE Patents [OSTI]

Electrical interconnects for solar cells or other electronic components using a silver-silicone paste or a lead-tin (Pb--Sn) no-clean fluxless solder cream, whereby the high breakage of thin (<6 mil thick) solar cells using conventional solder interconnect is eliminated. The interconnects of this invention employs copper strips which are secured to the solar cells by a silver-silicone conductive paste which can be used at room temperature, or by a Pb--Sn solder cream which eliminates undesired residue on the active surfaces of the solar cells. Electrical testing using the interconnects of this invention has shown that no degradation of the interconnects developed under high current testing, while providing a very low contact resistance value.

Carey, Paul G. (Mountain View, CA); Thompson, Jesse B. (Brentwood, CA); Colella, Nicolas J. (Livermore, CA); Williams, Kenneth A. (Livermore, CA)

2002-01-01T23:59:59.000Z

178

Modeling tin whisker growth.  

SciTech Connect (OSTI)

Tin, lead, and lead-tin solders are the most commonly used solders due to their low melting temperatures. However, due to the toxicity problems, lead must now be removed from solder materials. This has lead to the re-emergence of the issue of tin whisker growth. Tin whiskers are a microelectronic packaging issue because they can lead to shorts if they grow to sufficient length. However, the cause of tin whisker growth is still not well understood and there is lack of robust methods to determine when and if whiskering will be a problem. This report summarizes some of the leading theories on whisker growth and attempts to provide some ideas towards establishing the role microstructure plays in whisker growth.

Weinberger, Christopher Robert

2013-08-01T23:59:59.000Z

179

Automated solar cell assembly teamed process research. Semiannual subcontract report, December 6, 1993--June 30, 1994  

SciTech Connect (OSTI)

This is the second Semiannual Technical Progress Report for the program titled `Automated Solar Cell Assembly Teamed Process Research` funded under National Renewable Energy Laboratory (NREL) subcontract No. ZAG-3-11219-01. This report describes the work done on Phase II of the program in the period from December 6, 1993 to June 30, 1994. Spire`s objective in this program is to develop high throughput (5 MW/yr) automated processes for interconnecting thin (200 {mu}m) silicon solar cells. High yield will be achieved with these fragile cells through the development of low mechanical stress and low thermal stress processes. For example, a machine vision system is being developed for cell alignment without mechanically contacting the cell edges, while a new soldering process is being developed to solder metal interconnect ribbons simultaneously to a cells` front and back contacts, eliminating one of the two heating steps normally used for soldering each cell.

Nowlan, M. [Spire Corp., Bedford, MA (United States)

1995-01-01T23:59:59.000Z

180

A study of experimental techniques for analyzing threaded thick shell connections  

E-Print Network [OSTI]

and Solder Tabs Bottom of Encapsulated Gage Assembly. One Gage Assembly Bonded in Pin of Drill Collar Strain Gage Instrumented Drill Collar Pin Dimensions Used in Sample Calculations. Test Setup for Strain Gage Make-Up Data Inside Surface Hoop Stress vs... the specimens was limited to an in- side diameter of two inches. the strain gazes were prewired before being attached to the fixture. After the lead wire was soldered to the gQ4 aa Figure 3. Inside of Fixture Used to Bond Strain Gages. Figure 4. Assembled...

Asbill, William Thomas

2012-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Development of Readout Interconnections for the Si-W Calorimeter of SiD  

SciTech Connect (OSTI)

The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.

Woods, M.; Fields, R.G.; Holbrook, B.; Lander, R.L.; Moskaleva, A.; Neher, C.; Pasner, J.; Tripathi, M.; /UC, Davis; Brau, J.E.; Frey, R.E.; Strom, D.; /Oregon U.; Breidenbach, M.; Freytag, D.; Haller, G.; Herbst, R.; Nelson, T.; /SLAC; Schier, S.; Schumm, B.; /UC, Santa Cruz

2012-09-14T23:59:59.000Z

182

Metallurgy, thermal stability, and failure mode of the commercial Bi-Te-based thermoelectric modules.  

SciTech Connect (OSTI)

Bi-Te-based thermoelectric (TE) alloys are excellent candidates for power generation modules. We are interested in reliable TE modules for long-term use at or below 200 C. It is known that the metallurgical characteristics of TE materials and of interconnect components affect the performance of TE modules. Thus, we have conducted an extensive scientific investigation of several commercial TE modules to determine whether they meet our technical requirements. Our main focus is on the metallurgy and thermal stability of (Bi,Sb){sup 2}(Te,Se){sup 3} TE compounds and of other materials used in TE modules in the temperature range between 25 C and 200 C. Our study confirms the material suite used in the construction of TE modules. The module consists of three major components: AlN cover plates; electrical interconnects; and the TE legs, P-doped (Bi{sub 8}Sb{sub 32})(Te{sub 60}) and N-doped (Bi{sub 37}Sb{sub 3})(Te{sub 56}Se{sub 4}). The interconnect assembly contains Sn (Sb {approx} 1wt%) solder, sandwiched between Cu conductor with Ni diffusion barriers on the outside. Potential failure modes of the TE modules in this temperature range were discovered and analyzed. The results show that the metallurgical characteristics of the alloys used in the P and N legs are stable up to 200 C. However, whole TE modules are thermally unstable at temperatures above 160 C, lower than the nominal melting point of the solder suggested by the manufacture. Two failure modes were observed when they were heated above 160 C: solder melting and flowing out of the interconnect assembly; and solder reacting with the TE leg, causing dimensional swelling of the TE legs. The reaction of the solder with the TE leg occurs as the lack of a nickel diffusion barrier on the side of the TE leg where the displaced solder and/or the preexisting solder beads is directly contact the TE material. This study concludes that the present TE modules are not suitable for long-term use at temperatures above 160 C due to the reactivity between the Sn-solder and the (Bi,Sb){sup 2}(Te,Se){sup 3} TE alloys. In order to deploy a reliable TE power generator for use at or below 200 C, alternate interconnect materials must be used and/or a modified module fabrication technique must be developed.

Yang, Nancy Y. C.; Morales, Alfredo Martin

2009-02-01T23:59:59.000Z

183

Technique for Measuring Hybrid Electronic Component Reliability  

SciTech Connect (OSTI)

Materials compatibility studies of aged, engineered materials and hardware are critical to understanding and predicting component reliability, particularly for systems with extended stockpile life requirements. Nondestructive testing capabilities for component reliability would significantly enhance lifetime predictions. For example, if the detection of crack propagation through a solder joint can be demonstrated, this technique could be used to develop baseline information to statistically determine solder joint lifelengths. This report will investigate high frequency signal response techniques for nondestructively evaluating the electrical behavior of thick film hybrid transmission lines.

Green, C.C.; Hernandez, C.L.; Hosking, F.M.; Robinson, D.; Rutherford, B.; Uribe, F.

1999-01-01T23:59:59.000Z

184

Development of Readout Interconnections for the Si-W Calorimeter of SiD  

E-Print Network [OSTI]

The SiD collaboration is developing a Si-W sampling electromagnetic calorimeter, with anticipated application for the International Linear Collider. Assembling the modules for such a detector will involve special bonding technologies for the interconnections, especially for attaching a silicon detector wafer to a flex cable readout bus. We review the interconnect technologies involved, including oxidation removal processes, pad surface preparation, solder ball selection and placement, and bond quality assurance. Our results show that solder ball bonding is a promising technique for the Si-W ECAL, and unresolved issues are being addressed.

M. Woods; R. G. Fields; B. Holbrook; R. L. Lander; A. Moskaleva; C. Neher; J. Pasner; M. Tripathi; J. E. Brau; R. E. Frey; D. Strom; M. Breidenbach; D. Freytag; G. Haller; R. Herbst; T. Nelson; S. Schier; B. Schumm

2011-11-21T23:59:59.000Z

185

Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts  

SciTech Connect (OSTI)

This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

2005-01-30T23:59:59.000Z

186

Measurement of Resistance and Strength of Conductor Splices in the MICE Coupling Magnets  

SciTech Connect (OSTI)

The superconducting magnets for the Muon Ionization Cooling Experiment [1] (MICE) use a copper based Nb-Ti conductor with un-insulated dimensions of 0.95 by 1.60 mm. There may be as many as twelve splices in one MICE superconducting coupling coil. These splices are to be wound in the coil. The conductor splices produce Joule heating, which may cause the magnet to quench. A technique of making conductor splices was developed by ICST. Two types of 1-meter long of soldered lap-joints have been tested. Side-by-side splices and up-down one splices were studied theoretically and experimentally using two types of soft solder made of eutectic tin-lead solder and tin-silver solder. The resistances of the splices made by ICST were tested at LBNL at liquid helium temperatures over a range of magnetic fields up to 5 T. The breaking strength of 250 mm long splices was also measured at room temperature and liquid nitrogen temperature.

Xu, Feng Yu; Pan, Heng; Wu, Hong; Lui, X. K.; Li, E.; Dietderich, Dan; Higley, Hugh; Tam, D. G.; Trillaud, Fredric; Wang, Li; Green, M.A.

2009-08-19T23:59:59.000Z

187

ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton GIT 2011  

E-Print Network [OSTI]

temperatures, easy to diffusion bond. · Iron, titanium and copper also can be diffusion bonded, because · Diffusion bonding · Soldering and brazing · Fusion welding #12;ME 6222: Manufacturing Processes and Systems Prof. J.S. Colton © GIT 2011 3 Diffusion bonding · High pressure and temperature for extended periods

Colton, Jonathan S.

188

A probe for investigating the effects of temperature, strain, and magnetic field on transport critical currents in superconducting  

E-Print Network [OSTI]

magnetic fields. The strain is applied to the wire by soldering it to a thick coiled spring and twisting one end of the spring with respect to the other. Strain can be applied reversibly from 0.7% to 0 to test long straight samples can be constructed for use in split-coil magnets, but the maximum field

Hampshire, Damian

189

Reliability Analysis of Microelectronic Components and Materials  

E-Print Network [OSTI]

1 Reliability Analysis of Microelectronic Components and Materials Increasing numbers of the degradation processes relevant to soldered joints is crucial for more reliable life-cycle predictions. Joining methods are critical for the reliable use of electronic packages. In particular, since the advent

Berlin,Technische UniversitƤt

190

Accelerators | Photon Science | Particle Physics Deutsches Elektronen-Synchrotron  

E-Print Network [OSTI]

design, PCB layout and prototyping Ā· Ensure testing and documentation of electonic circuits Ā· Interact-on experience in electronic circuit design, PCB layout and circuit testing as well as soldering skills. The position Ā· Develop essential electronic circuits for novel laser systems at DESY Ā· Responsible for circuit

191

Open Archive TOULOUSE Archive Ouverte (OATAO) OATAO is an open access repository that collects the work of Toulouse researchers and  

E-Print Network [OSTI]

power modules devices are paramount components in the aeronautical, automotive and military applications management (Fig .1). The dielectric ceramic substrate is double bonded with thick copper or aluminum such as AlSiC, copper or aluminum. The brazing is achieved using solder alloys considered as one

Paris-Sud XI, UniversitƩ de

192

Digit switch evaluations and capillary IPA (isopropyl alcohol) study  

SciTech Connect (OSTI)

Capillary flow of isopropyl alcohol under the wire insulation of an eleven-wire cable dissolved trapped flux from the pretinning and soldering operations and caused it to deposit on the circuit board inside a digit switch. Conformal coatings were successful in sealing the wire insulation gap to prevent solvent flow. 16 figs., 2 tabs.

Mizik, P.M.; Kibalo, E.F.

1990-12-01T23:59:59.000Z

193

Air Gap Tunin Yilin Mao, Yashwanth  

E-Print Network [OSTI]

Air Gap Tunin Yilin Mao, Yashwanth Electrical Engineering Departm The Unive ymao1@olemiss.edu, ypadooru@ Abstract-- An adjustable air gap was proposed the resonant frequency of patch antennas the frequency of coaxially fed p center conductor has to be de-soldered and r time the width of the air gap

Elsherbeni, Atef Z.

194

Thermo-mechanical simulations in double-sided heat transfer power assemblies.  

E-Print Network [OSTI]

Thermo-mechanical simulations in double-sided heat transfer power assemblies. E. Woirgard; I. Favre In power assemblies, heat transfer due to the die self- heating is one of the most important point on time life assemblies. Heat has to be evacuated toward the base- plate not to weaken the solder joint under

Boyer, Edmond

195

The elemental interaction in the electrodeposited Pb-Sn/electroless Ni-P deposit/Al multilayer upon heat treatment  

SciTech Connect (OSTI)

The deposition of electroless nickel on aluminum is a relatively simple process. It is thus feasible to manufacture an electrodeposited solder bump on aluminum with the aid of an electroless nickel intermediate layer. The Al/electroless Ni/Pb-SN combination has been successfully developed in the present work. For this application, however, it is necessary to understand the possible interactions during protracted utilization of the multilayer combination. Nickel is reported to undergo the smallest rate of dissolution and the rate of reaction with solder among various materials is commonly applied in electronics. Thus, nickel has been applied as a diffusion barrier in electronic packaging. Electroless nickel is expected to have a similar barrier property. The interaction between nickel and electrodeposited tin forms Ni[sub 3]Sn[sub 4] at 190 C (12); Ni[sub 3]Sn is formed when the nickel surface is roughened. Ni[sub 3]Sn[sub 2] was found after soldering on electroless Ni-P. Despite all this work, there are still few investigations on the behavior of electrodeposited solder and electroless nickel deposits. The authors investigated the interphases formed in the Al/electroless Ni-P/Pb-Sn electro-deposit multilayer combination.

Lin, K.L.; Chang, J.T. (National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Materials Science and Engineering)

1994-03-01T23:59:59.000Z

196

Preparation of Ni-Sn alloys by an electroless-deposition method  

SciTech Connect (OSTI)

Ni-Sn alloy is expected for as a functional material, because of its excellent corrosion resistance, wear resistance, and solderability. Electroless-deposited Ni-Sn alloy films were investigated to increase tin content in the deposit. The maximum tin contents of electroless Ni-Sn-P and Ni-Sn-B were ca. 30 atom percent (a/o) and 42 a/o, respectively. The maximum tin contents in the case of Ni-Sn-B was nearly equal to that of electrodeposited Ni-Sn alloy already reported. The crystallinity of Ni-Sn-P and Ni-Sn-B alloys was raised up with an increase in tin content. The corrosion resistance of Ni-Sn-P and Ni-Sn-B alloys was between that of amorphous and crystalline electroless-deposited Ni-P. Codeposition of tin into Ni-P films improved solderability, but into the Ni-B films, the solderability of Ni-Sn-B films situated in the region between those of Ni-P and NiB, because the solderability of NiB is higher.

Shimauchi, Hidenori; Ozawa, Susumu; Tamura, Keiu; Osaka, Tetsuya (Waseda Univ., Tokyo (Japan). Dept. of Applied Chemistry)

1994-06-01T23:59:59.000Z

197

The series is designed to provide an industry perspective on smart lighting technologies and markets. Each speaker will also share personal insights about their career paths.  

E-Print Network [OSTI]

market spaces such as display, automotive and general lighting. Product performance and reliability. This talk describes some of the issues related to LED product performance and reliability and how advanced and solder materials for semiconductor packaging. Alpha also offers product technologies for the Photovoltaic

Varela, Carlos

198

-Ris Report No. 371 Ris National Laboratory  

E-Print Network [OSTI]

RADIOGRAPHY PAPER PHOTOGRAPHIC FILMS QUALITY CONTROL REVIEWS SOLDERED JOINTS USES WELDED JOINTS X of the radiographic image was checked on U/Al blocks and plates, Al and Fe blocks, and fiber-reinforced composites.2. Radiographic quality of U/Al blocks 89 7.3. Radiographic quality of Al and Fe blocks 90 7.4. Radiographic

199

PERMIT FOR WELDING AND CUTTING OPERATIONS INSTRUCTIONS: This permit must be completed for all operations involving open  

E-Print Network [OSTI]

PERMIT FOR WELDING AND CUTTING OPERATIONS INSTRUCTIONS: This permit must be completed for all/Area: Description of Work to be Performed: (check where appropriate) Welding Cutting Soldering Burning Type OF ACCIDENTAL FIRES DUE TO WELDING OR CUTTING OPERATIONS 1: Do not perform cutting or welding work where an open

Papautsky, Ian

200

Optical Inspection of Welding Seams Fabian Timm1,2  

E-Print Network [OSTI]

Optical Inspection of Welding Seams Fabian Timm1,2 , Thomas Martinetz1 , and Erhardt Barth1,2 1 present a framework for automatic inspection of welding seams based on specular reflections. To this end by using welding techniques. Soldering and welding techniques are common in diverse areas such as printed

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

2006 Minerals Yearbook U.S. Department of the Interior  

E-Print Network [OSTI]

metal consumed domestically was $394 million. Industry stocks at yearend increased by 46% compared scrapped alloys of tin and recycled in those same alloy industries. Secondary tin from recycled fabricated% of the reported primary tin used domestically. The major uses were as follows: electrical solders, 28%; metal

202

Appendixes Appendix I. Published Reports of Less Common Causes of Elevated Blood Lead Levels (EBLLs) in Children.  

E-Print Network [OSTI]

Description Ref. # Occupational Take Home Exposures Battery reclamation Lead carried home by battery workers. (Only a minority of battery workers showered or changed clothes before going home.) E Twelve (75%) of 16 Bulk-water storage tank Lead leached from soldered seams and brass fittings in bulk- water storage

203

154 Clocks, Atomic nnd Molccular connections. Chips can be attached to packages with win  

E-Print Network [OSTI]

, beam leads, beam tape,or solder pads. At present, the minimum line width and line spacingsused. SemiconductorDevices. Physics and Technology.Wiley. D. A. Hodges and H. G. Jackson, Analysis and Design of a seriesofperiodicevents(such as swings of a pendulum, passages of the sun overhead, or oscillationsof an atom

204

Welding Process Fundamentals* Thomas W. Eagar and Aaron D. Mazzeo, Massachusetts Institute of Technology  

E-Print Network [OSTI]

(such as fastening, adhesive bonding, soldering, brazing, arc welding, diffusion bonding, and resistance the material surrounding it. Although some pro- cesses, such as diffusion bonding, can achieve results solids will bond if their surfaces are brought into intimate contact. One factor that generally inhibits

Eagar, Thomas W.

205

Low Temperature Transient Liquid Phase (LTTLP) Bonding for Au/Cu  

E-Print Network [OSTI]

of Technology, Cambridge, MA 02139 TheLow Temperature TransientLiquidPhase Diffusion Bonding (LTTLP) process has) ) M. M. Hou Low Temperature Transient Liquid Phase (LTTLP) Bonding for Au/Cu and Cu been bonded to copper heatsink.s at temperatures less than 160"C, using /n-Sn eutectic solders. After

Eagar, Thomas W.

206

Almost everyone knows that lead-based paint caused serious health problems  

E-Print Network [OSTI]

such as contaminat- ed food and drinking water. Imported foods in lead- soldered cans and foods served in lead. It accumulates in the body and can cause lead poisoning. Even at low concen- trations, when there are no outward poisoning may diminish if the source of exposure is removed, but some damage is permanent. Symptoms of lead

207

PHYSICS DIVISION ESH BULLETIN 11-03  

E-Print Network [OSTI]

/or RADIATION ­ Welding: Electric Arc. Optical radiation Welding helmets or welding shields. Typical shades: 10-14. See notes (9), (12). WELDING: Gas Optical radiation Welding goggles or welding face shield. Typical soldering. Optical radiation Spectacles or welding face shield. Typical shades: 1.5-3. See notes (3), (9

208

1 Copyright 2007 by ASME Proceedings of IMECE 2007  

E-Print Network [OSTI]

the likelihood of arcing across solder nodes for high-power components. An #12;2 Copyright © 2007 by ASME b. Back1 Copyright © 2007 by ASME Proceedings of IMECE 2007 2007 ASME International Mechanical Engineering_Bigdeli@Whirlpool.com ABSTRACT The problem of arc tracking in power electronic enclosures was studied through simple bench

Texas at Arlington, University of

209

Flow visualization of molten alloys using real-time neutron radiography  

E-Print Network [OSTI]

The objective of this research is to visualize the flow of molten alloys using real-time neutron radiography. Initial experiments were performed using solder (50% tin, 50% lead), with nickel tracer particles, heated in a furnace to its liquid state...

Bennett, Tami Norene

1994-01-01T23:59:59.000Z

210

WAVELENGTH CONVERSION OVER A 50nm INPUT AND 21nm OUTPUT WAVELENGTH RANGE USING A MONOLITHICALLY  

E-Print Network [OSTI]

with the device soldered on a gold plated copper mount and cooled to 17Ā°C using a thermo-electric cooler. Light tuning range are shown in Figure 2a). A typical electrical extinction of the device for high MZI-SOA bias

Coldren, Larry A.

211

KV-tOOJHfe Metallurgy Department  

E-Print Network [OSTI]

.1. Fracture Testing 24 3.2. Fatigue Testing Using Offshore Load Spectrum .. 25 3.3. Brazing and Soldering 25 3 Research on Advanced Ceramic Materials 37 4.8. Developaent and Testing of Oxygen Sensors 38 FUEL ELEMENTS concentrated mainly on nuclear metallurgy to covering a number of different areas within ma- terials science

212

How To Order Our easy Build-A Switch concept allows you to mix and match options to create the switch you need. Below is a complete listing of  

E-Print Network [OSTI]

Series 8mm DIP Coded Rotary Switches Features/Benefits Ā· Process sealed Ā­ withstands soldering Example: Switch Function CD08R 8 position, BCD CD08C 8 position, BCD complement CD10R 10 position, BCD CD10C 10 position, BCD complement CD16R 16 position, Hexadecimal CD16C 16 position, Hexadecimal

Berns, Hans-Gerd

213

High-Temperature Die-Attaches for SiC Power Devices Amandine MASSON1, Cyril BUTTAY1, Herve MOREL1, Christophe RAYNAUD1,  

E-Print Network [OSTI]

of the solder joint degrade. The ratio between the melting temperature (Tm) and the operating temperature (To electronic systems which will be installed in hot areas. SiC power devices can operate at high temperature operating temperature range. Furthermore, the reliability of the attach is directly linked to its operating

Paris-Sud XI, UniversitƩ de

214

Areal array jetting device for ball grid arrays  

SciTech Connect (OSTI)

Package designs for microelectronics devices have moved from through-hole to surface mount technology in order to increase the printed wiring board real estate available by utilizing both sides of the board. The traditional geometry for surface mount devices is peripheral arrays where the leads are on the edges of the device. As the technology drives towards high input/output (I/O) count (increasing number of leads) and smaller packages with finer pitch (less distance between peripheral leads), limitations on peripheral surface mount devices arise. A solution to the peripheral surface mount issue is to shift the leads to the area under the device. This scheme is called areal array packaging and is exemplified by the ball grid array (BGA) package. In a BGA package, the leads are on the bottom surface of the package in the form of an array of solder balls. The current practice of joining BGA packages to printed wiring boards involves a hierarchy of solder alloy compositions. A high melting temperature ball is typically used for standoff. A promising alternative to current methods is the use of jetting technology to perform monolithic solder ball attachment. This paper describes an areal array jetter that was designed and built to simultaneously jet arrays of solder balls directly onto BGA substrates.

Frear, D.R.; Yost, F.G.; Schmale, D.T.; Essien, M.

1997-08-01T23:59:59.000Z

215

The 6th ASME-JSME Thermal Engineering Joint Conference March 16-20, 2003  

E-Print Network [OSTI]

conductivity interface materials and thus reduce the thermal resistance of the lasers. Copper heat spreaders samples. A two-dimensional analytical model is developed to verify the thermal resistance experimental conductivity solder materials, which can limit the performance of the laser [7, 13]. NOMENCLATURE K thermal

216

Thermionic emission cooling in single barrier heterostructures Ali Shakouria)  

E-Print Network [OSTI]

is an indication of the relatively high thermal resistance of the ceramic package and the soldering layer used, they absorb thermal energy from the lattice and this will cool down the junction between two materials high-speed and wavelength division multiplexed fiber- optics communication systems. Heat generation

217

Liquid Wall Science in other Scientific Pursuits and Applications  

E-Print Network [OSTI]

/sheet/ribbon/sphere casting, flood/jet soldering, ocean waves, hull design, ocean/river hydraulic engineering, surfing, liquid, wetted-wall absorbers/chemical reactor, condensers, vertical tube evaporator, film cooling of turbine vortices; ·Low Joule and Viscous dissipation; ·Insignificant effect on the hydraulic drag. 2-D turbulence

Abdou, Mohamed

218

Kinesthetic Learning in the Classroom "Great ideas originate in the muscles" Thomas Edison  

E-Print Network [OSTI]

and soldering a circuit board, connecting and sealing tubes in a flow loop or drilling a precise hole, these skills are practiced and mastered in a lab setting. The version of kinesthetic learning considered here to be signatures of a mature mind, humans learn best by doing something concrete first, and then abstracting

Tranquillo, Joseph V.

219

Should you have your water tested?  

E-Print Network [OSTI]

dissolved solids (TDS), corrosion index, and other parameters depending on proximity to potential sources guests have recurrent incidents of gastrointestinal illness. Household water plumbing contains lead pipes, fittings, or solder joints. You are buying a home and wish to assess the safety and quality of the existing

O'Laughlin, Jay

220

Leaching studies for tin recovery from waste e-scrap  

SciTech Connect (OSTI)

Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5 M HCl at fixed pulp density 50 g/L and temperature 90 Degree-Sign C in mixing time 165 min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68 kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5 M HCl at 90 Degree-Sign C, mixing time 60 min and pulp density 50 g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1 M nitric acid at 90 Degree-Sign C in mixing time 45 min and pulp density 10 g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.

Jha, Manis Kumar, E-mail: maniskrjha@gmail.com [Metal Extraction and Forming Division, National Metallurgical Laboratory (NML), Jamshedpur 831 007 (India); Choubey, Pankaj Kumar; Jha, Amrita Kumari; Kumari, Archana [Metal Extraction and Forming Division, National Metallurgical Laboratory (NML), Jamshedpur 831 007 (India); Lee, Jae-chun, E-mail: jclee@kigam.re.kr [Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350 (Korea, Republic of); Kumar, Vinay [Metal Extraction and Forming Division, National Metallurgical Laboratory (NML), Jamshedpur 831 007 (India); Jeong, Jinki [Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources, Daejeon 305-350 (Korea, Republic of)

2012-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Microwave spectrum of o-benzyne produced in a discharge nozzle S. G. Kukolicha)  

E-Print Network [OSTI]

Department of Chemistry, University of Arizona, Tucson, Arizona 85721 M. C. McCarthy and P. Thaddeus Harvard recently been implicated in gasoline combustion reactions and antitumor activity of enediynes. Twenty that o-benzyne may play a significant role in the combustion of lead-free gasoline. The theoretical

222

Phosphate glasses for radioactive, hazardous and mixed waste immobilization  

DOE Patents [OSTI]

Lead-free phosphate glass compositions are provided which can be used to immobilize low level and/or high level radioactive wastes in monolithic waste forms. The glass composition may also be used without waste contained therein. Lead-free phosphate glass compositions prepared at about 900.degree. C. include mixtures from about 1 mole % to about 6 mole %.iron (III) oxide, from about 1 mole % to about 6 mole % aluminum oxide, from about 15 mole % to about 20 mole % sodium oxide or potassium oxide, and from about 30 mole % to about 60 mole % phosphate. The invention also provides phosphate, lead-free glass ceramic glass compositions which are prepared from about 400.degree. C. to about 450.degree. C. and which includes from about 3 mole % to about 6 mole % sodium oxide, from about 20 mole % to about 50 mole % tin oxide, from about 30 mole % to about 70 mole % phosphate, from about 3 mole % to about 6 mole % aluminum oxide, from about 3 mole % to about 8 mole % silicon oxide, from about 0.5 mole % to about 2 mole % iron (III) oxide and from about 3 mole % to about 6 mole % potassium oxide. Method of making lead-free phosphate glasses are also provided.

Cao, Hui (Middle Island, NY); Adams, Jay W. (Stony Brook, NY); Kalb, Paul D. (Wading River, NY)

1999-03-09T23:59:59.000Z

223

Phosphate glasses for radioactive, hazardous and mixed waste immobilization  

DOE Patents [OSTI]

Lead-free phosphate glass compositions are provided which can be used to immobilize low level and/or high level radioactive wastes in monolithic waste forms. The glass composition may also be used without waste contained therein. Lead-free phosphate glass compositions prepared at about 900.degree. C. include mixtures from about 1 mole % to about 6 mole % iron (III) oxide, from about 1 mole % to about 6 mole % aluminum oxide, from about 15 mole % to about 20 mole % sodium oxide or potassium oxide, and from about 30 mole % to about 60 mole % phosphate. The invention also provides phosphate, lead-free glass ceramic glass compositions which are prepared from about 400.degree. C. to about 450.degree. C. and which includes from about 3 mole % to about 6 mole % sodium oxide, from about 20 mole % to about 50 mole % tin oxide, from about 30 mole % to about 70 mole % phosphate, from about 3 mole % to about 6 mole % aluminum oxide, from about 3 mole % to about 8 mole % silicon oxide, from about 0.5 mole % to about 2 mole % iron (III) oxide and from about 3 mole % to about 6 mole % potassium oxide. Method of making lead-free phosphate glasses are also provided.

Cao, Hui (Middle Island, NY); Adams, Jay W. (Stony Brook, NY); Kalb, Paul D. (Wading River, NY)

1998-11-24T23:59:59.000Z

224

INSTITUTE OF PHYSICS PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 37 (2004) 921924 PII: S0022-3727(04)72598-X  

E-Print Network [OSTI]

by the Czochralski method. X-ray energy dispersive spectrometry showed that SBNN70 crystals have a stoichiometric, and a deep energy level of 3.54 eV was found. The SBNN70 crystal has better than 70% optical transmittance of lead- free ferroelectric materials with a high Curie temperature and better functional properties

Cao, Wenwu

225

High thermoelectric performance by resonant dopant indium in nanostructured SnTe  

E-Print Network [OSTI]

From an environmental perspective, lead-free SnTe would be preferable for solid-state waste heat recovery if its thermoelectric figure-of-merit could be brought close to that of the lead-containing chalcogenides. In this ...

Liao, Bolin

226

Phosphate glasses for radioactive, hazardous and mixed waste immobilization  

DOE Patents [OSTI]

Lead-free phosphate glass compositions are provided which can be used to immobilize low level and/or high level radioactive wastes in monolithic waste forms. The glass composition may also be used without waste contained therein. Lead-free phosphate glass compositions prepared at about 900 C include mixtures from about 1 mole % to about 6 mole % iron (III) oxide, from about 1 mole % to about 6 mole % aluminum oxide, from about 15 mole % to about 20 mole % sodium oxide or potassium oxide, and from about 30 mole % to about 60 mole % phosphate. The invention also provides phosphate, lead-free glass ceramic glass compositions which are prepared from about 400 C to about 450 C and which includes from about 3 mole % to about 6 mole % sodium oxide, from about 20 mole % to about 50 mole % tin oxide, from about 30 mole % to about 70 mole % phosphate, from about 3 mole % to about 6 mole % aluminum oxide, from about 3 mole % to about 8 mole % silicon oxide, from about 0.5 mole % to about 2 mole % iron (III) oxide and from about 3 mole % to about 6 mole % potassium oxide. Method of making lead-free phosphate glasses are also provided. 8 figs.

Cao, H.; Adams, J.W.; Kalb, P.D.

1999-03-09T23:59:59.000Z

227

Phosphate glasses for radioactive, hazardous and mixed waste immobilization  

DOE Patents [OSTI]

Lead-free phosphate glass compositions are provided which can be used to immobilize low level and/or high level radioactive wastes in monolithic waste forms. The glass composition may also be used without waste contained therein. Lead-free phosphate glass compositions prepared at about 900 C include mixtures from about 1--6 mole % iron (III) oxide, from about 1--6 mole % aluminum oxide, from about 15--20 mole % sodium oxide or potassium oxide, and from about 30--60 mole % phosphate. The invention also provides phosphate, lead-free glass ceramic glass compositions which are prepared from about 400 C to about 450 C and which includes from about 3--6 mole % sodium oxide, from about 20--50 mole % tin oxide, from about 30--70 mole % phosphate, from about 3--6 mole % aluminum oxide, from about 3--8 mole % silicon oxide, from about 0.5--2 mole % iron (III) oxide and from about 3--6 mole % potassium oxide. Method of making lead-free phosphate glasses are also provided. 8 figs.

Cao, H.; Adams, J.W.; Kalb, P.D.

1998-11-24T23:59:59.000Z

228

Explosive complexes  

DOE Patents [OSTI]

Lead-free primary explosives of the formula [M.sup.II(A).sub.R(B.sup.X).sub.S](C.sup.Y).sub.T, where A is 1,5-diaminotetrazole, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

Huynh, My Hang V. (Los Alamos, NM)

2009-09-22T23:59:59.000Z

229

Explosive complexes  

SciTech Connect (OSTI)

Lead-free primary explosives of the formula [M.sup.II(A).sub.R(B.sup.X).sub.S](C.sup.Y).sub.T, where A is 1,5-diaminotetrazole, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

Huynh, My Hang V. (Los Alamos, NM)

2011-08-16T23:59:59.000Z

230

Multi-lead heat sink  

DOE Patents [OSTI]

The disclosure relates to a heat sink used to protect integrated circuits from the heat resulting from soldering them to circuit boards. A tubular housing contains a slidable member which engages somewhat inwardly extending connecting rods, each of which is rotatably attached at one end to the bottom of the housing. The other end of each rod is fastened to an expandable coil spring loop. As the member is pushed downward in the housing, its bottom edge engages and forces outward the connecting rods, thereby expanding the spring so that it will fit over an integrated circuit. After the device is in place, the member is slid upward and the spring contracts about the leads of the integrated circuit. Soldering is now conducted and the spring absorbs excess heat therefrom to protect the integrated circuit. The placement steps are repeated in reverse order to remove the heat sink for use again.

Roose, Lars D. (Albuquerque, NM)

1984-01-01T23:59:59.000Z

231

Multi-lead heat sink  

DOE Patents [OSTI]

The disclosure relates to a heat sink used to protect integrated circuits from the heat resulting from soldering them to circuit boards. A tubular housing contains a slidable member which engages somewhat inwardly extending connecting rods, each of which is rotatably attached at one end to the bottom of the housing. The other end of each rod is fastened to an expandable coil spring loop. As the member is pushed downward in the housing, its bottom edge engages and forces outward the connecting rods, thereby expanding the spring so that it will fit over an integrated circuit. After the device is in place, the member is slid upward and the spring contracts about the leads of the integrated circuit. Soldering is now conducted and the spring absorbs excess heat therefrom to protect the integrated circuit. The placement steps are repeated in reverse order to remove the heat sink for use again.

Roose, L.D.

1982-08-25T23:59:59.000Z

232

Multi-lead heat sink  

DOE Patents [OSTI]

The disclosure relates to a heat sink used to protect integrated circuits from the heat resulting from soldering them to circuit boards. A tubular housing contains a slidable member which engages somewhat inwardly extending connecting rods, each of which is rotatably attached at one end to the bottom of the housing. The other end of each rod is fastened to an expandable coil spring loop. As the member is pushed downward in the housing, its bottom edge engages and forces outward the connecting rods, thereby expanding the spring so that it will fit over an integrated circuit. After the device is in place, the member is slid upward and the spring contracts about the leads of the integrated circuit. Soldering is now conducted and the spring absorbs excess heat therefrom to protect the integrated circuit. The placement steps are repeated in reverse order to remove the heat sink for use again. 4 figs.

Roose, L.D.

1984-07-03T23:59:59.000Z

233

Phase 2 of the array automated assembly task for the low cost silicon solar array project. Fifth quarterly report  

SciTech Connect (OSTI)

This program focuses attention on one key step of a proposed process sequence for mass production of inexpensive silicon solar arrays for terrestrial use. The process step of concern is the metallization of the solar cell. Solarex has proposed that the metallization be accomplished by a single electroless plating of nickel followed by a dip in molten solder, and Solarex manufactures solar cells using this procedure. ing, cleaning and annealing. Motorola has recommended a process which includes the electroless nickel plate and solder dip of the Solarex process, but which precedes these steps with a number of additional steps of palladium plating, cleaning and annealing. Motorola has claimed that these additional steps are necessary to assure proper ohmic contact with the silicon while at the same time avoiding excessive nickel penetration into the silicon. This program comprises a technical comparison of the Solarex and Motorola processes. Progress is reported.

Petersen, R.C.; Anderson, J.R.

1980-01-01T23:59:59.000Z

234

Study of bump bonding technology  

SciTech Connect (OSTI)

Pixel detectors proposed for the new generation of hadron collider experiments will use bump-bonding technology based on either indium or Pb/Sn solder to connect the front-end readout chips to the silicon pixel sensors. We have previously reported large-scale tests of the yield using both indium and Pb/Sn solder bump [1]. The conclusion is that both seem to be viable for pixel detectors. We have also carried out studies of various effects (e.g. storage over long period, effect of heating and cooling, and radiation) on both types of bump bonds using daisy-chained parts on a small scale [2], [3]. Overall, these tests showed little changes in the integrity of the bump connections. Nevertheless, questions still remain on the long-term reliability of the bumps due to thermal cycle effects, attachment to a substrate with a different coefficient of thermal expansion (CTE), and radiation.

Selcuk Cihangir et al.

2003-10-17T23:59:59.000Z

235

An investigation into the mechanical response of Berea sandstone to the uniaxial-biaxial test  

E-Print Network [OSTI]

collar. Shaded vertical line represents the solder bead laid to hold the strip of lead together. b) Appearance of lead collar if it were laid on a flat surface with layout of axial and circumferential gauges. 16 Completed assembly of strain gauged... variety of stress and strain states. Tests under conditions of uniaxial strain and other loading paths will lead to a better understanding of the bounds of deformation. Additionally, many authors (including This thesis follows the style of the Journal...

Denton, Meredith Yrette

2012-06-07T23:59:59.000Z

236

The role of electroplated coatings in metal joining  

SciTech Connect (OSTI)

Electroplated and electroless coatings often play an important role in soldering, brazing, and welding operations. Thin deposits applied to critical surfaces before the joining operations can provide the difference between success and failure. Diffusion welding applications sometimes require coatings to help promote joining. For some applications, electroplating by itself can be used to join metals that cannot be welded or brazed because of metallurgical incompatibility. The use of electroplated coatings for these various joining applications is reviewed here.

Dini, J.W. [Lawrence Livermore National Lab., CA (United States)

1996-05-01T23:59:59.000Z

237

Development of the bus joint for the ITER Central Solenoid  

SciTech Connect (OSTI)

The terminations of the Central Solenoid (CS) modules are connected to the bus extensions by joints located outside the CS in the gap between the CS and Torodial Field (TF) assemblies. These joints have very strict space limitations. Low resistance is a common requirement for all ITER joints. In addition, the CS bus joints will experience and must be designed to withstand significant variation in the magnetic field of several tenths of a Tesla per second during initiation of plasma. The joint resistance is specified to be less than 4 nOhm. The joints also have to be soldered in the field and designed with the possibility to be installed and dismantled in order to allow cold testing in the cold test facility. We have developed coaxial joints that meet these requirements and have demonstrated the feasibility to fabricate and assemble them in the vertical configuration. We introduced a coupling cylinder with superconducting strands soldered to the surface of the cable that can be installed in the ITER assembly hall and at the Cold Test Facility. This cylinder serves as a transition area between the CS module and the bus extension. We made two racetrack samples and tested four bus joints in our Joint Test Apparatus. Resistance of the bus joints was measured by a decay method and by a microvoltmeter; the value of the current was measured by the Hall probes. This measurement method was verified in the previous tests. The resistance of the joints varied insignificantly from 1.5 to 2 nOhm. One of the challenges associated with a soldered joint is the inability to use corrosive chemicals that are difficult to clean. This paper describes our development work on cable preparation, chrome removal, compaction, soldering, and final assembly and presents the test results.

Martovetsky, Nicolai N [ORNL] [ORNL; Irick, David Kim [ORNL] [ORNL; Kenney, Steven J [ORNL] [ORNL

2013-01-01T23:59:59.000Z

238

Low resistivity contact to iron-pnictide superconductors  

DOE Patents [OSTI]

Method of making a low resistivity electrical connection between an electrical conductor and an iron pnictide superconductor involves connecting the electrical conductor and superconductor using a tin or tin-based material therebetween, such as using a tin or tin-based solder. The superconductor can be based on doped AFe.sub.2As.sub.2, where A can be Ca, Sr, Ba, Eu or combinations thereof for purposes of illustration only.

Tanatar, Makariy; Prozorov, Ruslan; Ni, Ni; Bud'ko, Sergey; Canfield, Paul

2013-05-28T23:59:59.000Z

239

An assessment of alternatives for replacing Freon 113 in bench type electrical circuit board cleaning at Fermi National Accelerator Laboratory  

SciTech Connect (OSTI)

Fermilab is presently phasing out all solvents containing Freon-113 (CFC-113) as part of the continuing Waste Minimization Program. These solvents are used primarily in cleaning the flux off of electronic circuit boards after soldering, specifically in bench type work. Title VI of the Clean Air Act mandates a production phase-out for ozone depleting substances, like CFC-113, by the year 2000. Our study addresses this issue by evaluating and choosing alternative non-CFC solvents to replace the CFC-1 13 solvents at Fermilab. Several potential non-CFC cleaning solvents were tested. The evaluation took place in three parts: controlled experimental evaluation, chemical composition evaluation, and employee performed evaluation. First, we performed a controlled nine-step procedure with the potential solvents where each was evaluated in categories such as cleaning effectiveness, odor, residue, type of output and drying time. Next, we listed the chemical composition of each solvent. We noted which solvents contained hydrochlorofluorocarbons because they are targeted for phase-out in the future and will be recognized as interim solutions only. Finally, after preliminary testing, five solvents were chosen as the best options. These solvents were sent to be tested by Fermilab employees who use such materials. Their opinions are valuable not only because they are knowledgeable in this field, but also because they will be using the solvents chosen to replace the CFC-113 solvents. The results favored two ``best alternatives``: Safezone Solvent Flux Remover by Miller-Stephenson and E-Series CFC Free Flux-Off 2000 by Chemtech. Another possible solution also pursued is the no-clean solder option. In our study, we were not able to thoroughly investigate the many types of no-clean solders because of time and financial constraints. The testing that was done, however, showed that no-clean solder was a viable alternative in many cases.

Isakson, K.; Vessell, A.L.

1994-07-01T23:59:59.000Z

240

Drinking Water Standards  

E-Print Network [OSTI]

Ci/L) minerals that are radioactive and may emit a form of radiation known as alpha radiation IOC Antimony 0.006 Increase in blood cholesterol; decrease Discharge from petroleum refineries; 0.006 in blood sugar fire retardants; ceramics; electronics; solder....003 problems IOC Barium 2 Increase in blood pressure Discharge of drilling wastes; discharge 2 from metal refineries; erosion of natural deposits OC Benzene 0.005 Anemia; decrease in blood platelets; Discharge from factories; leaching from zero increased risk...

Dozier, Monty; McFarland, Mark L.

2006-04-26T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Planar triode pulser socket  

DOE Patents [OSTI]

A planar triode is mounted in a PC board orifice by means of a U-shaped capacitor housing and anode contact yoke removably attached to cathode leg extensions passing through and soldered to the cathode side of the PC board by means of a PC cathode pad. A pliant/flexible contact attached to the orifice make triode grid contact with a grid pad on the grid side of the PC board, permitting quick and easy replacement of bad triodes.

Booth, Rex (Livermore, CA)

1994-01-01T23:59:59.000Z

242

Planar triode pulser socket  

DOE Patents [OSTI]

A planar triode is mounted in a PC board orifice by means of a U-shaped capacitor housing and anode contact yoke removably attached to cathode leg extensions passing through and soldered to the cathode side of the PC board by means of a PC cathode pad. A pliant/flexible contact attached to the orifice make triode grid contact with a grid pad on the grid side of the PC board, permitting quick and easy replacement of bad triodes. 14 figs.

Booth, R.

1994-10-25T23:59:59.000Z

243

Crystal oscillator (1.0) (1.0)  

E-Print Network [OSTI]

.6 #2 5.02.4 2.7Max.5.8Max. 10.5 Max. Recommended soldering patternExternal dimensions Specifications time Oscillation start up time Aging Shock resistance Max. supply voltage Operating voltage Storage S.R. SG-636PTF SG-636PTJ SG-636PH Specifications 41.0001 MHz to 70.0000 MHz 2.21675 MHz to 41

Berns, Hans-Gerd

244

GOMA 6.0 : a full-Newton finite element program for free and moving boundary problems with coupled fluid/solid momentum, energy, mass, and chemical species transport : user%3CU%2B2019%3Es guide.  

SciTech Connect (OSTI)

Goma 6.0 is a finite element program which excels in analyses of multiphysical processes, particularly those involving the major branches of mechanics (viz. fluid/solid mechanics, energy transport and chemical species transport). Goma is based on a full-Newton-coupled algorithm which allows for simultaneous solution of the governing principles, making the code ideally suited for problems involving closely coupled bulk mechanics and interfacial phenomena. Example applications include, but are not limited to, coating and polymer processing flows, super-alloy processing, welding/soldering, electrochemical processes, and solid-network or solution film drying. This document serves as a user's guide and reference.

Schunk, Peter Randall; Rao, Rekha Ranjana; Chen, Ken Shuang; Labreche, Duane A.; Sun, Amy Cha-Tien; Hopkins, Matthew Morgan; Moffat, Harry K.; Roach, Robert Allen; Hopkins, Polly L.; Notz, Patrick K.; Roberts, Scott Alan; Sackinger, Philip A.; Subia, Samuel Ramirez; Wilkes, Edward Dean; Baer, Thomas A.; Noble, David R.; Secor, Robert B. [3M Engineering Systems and Technology, St. Paul, MN] [3M Engineering Systems and Technology, St. Paul, MN

2013-07-01T23:59:59.000Z

245

Helium dilution refrigeration  

E-Print Network [OSTI]

. 1875" OD exchanger Qu ID copper cap Fig. 6. Assembled view of 3He - He dilution refrigerator. 26 The joint thru the tubing wall and the joining of the two sizes of capillary were silver soldered (35/ silver content). A 0. 250" OD tube... the inert atmosphere inside the refrigerator. After removal from the nitrogen atmosphere the graphite support, was 'attached to the still and mixing chamber using Stycast 2850 GT with catalyst g9 ). The mass of the graphite 26 support 1s 11. 62 grams...

McKee, Thomas Raymond

2012-06-07T23:59:59.000Z

246

Tin electroplating/stripping evaluation. Topical report  

SciTech Connect (OSTI)

An evaluation was conducted to determine possible replacement chemistries for electroplating and stripping of tin-lead. The driver for this project was two-fold. Our first goal dealt with hazardous waste reduction. It was desired to eliminate lead (a heavy metal) from the electroplating process and thiourea (a known carcinogen) from the stripping process. We also sought to reduce the cost of nonconformance (CONC) realized by this process in the form of rough plating, broken paths, poor solderability, and overetching. Three suppliers` tin chemistries were evaluated as replacements for electroplating and stripping of tin-lead. Based on preliminary testing, one chemistry was chosen, evaluated, and approved for production use.

McHenry, M.R.

1995-08-01T23:59:59.000Z

247

Packaging of solid state devices  

DOE Patents [OSTI]

A package for one or more solid state devices in a single module that allows for operation at high voltage, high current, or both high voltage and high current. Low thermal resistance between the solid state devices and an exterior of the package and matched coefficient of thermal expansion between the solid state devices and the materials used in packaging enables high power operation. The solid state devices are soldered between two layers of ceramic with metal traces that interconnect the devices and external contacts. This approach provides a simple method for assembling and encapsulating high power solid state devices.

Glidden, Steven C.; Sanders, Howard D.

2006-01-03T23:59:59.000Z

248

Microstructural development and mechanical behavior of eutectic bismuth-tin and eutectic indium-tin in response to high temperature deformation  

SciTech Connect (OSTI)

The mechanical behavior and microstructure of eutectic Bi-Sn and In-Sn solders were studied in parallel in order to better understand high temperature deformation of these alloys. Bi-Sn solder joints were made with Cu substrates, and In-Sn joints were made with either Cu or Ni substrates. The as-cast microstructure of Bi-Sn is complex regular, with the two eutectic phases interconnected in complicated patterns. The as-cast microstructure of In-Sn depends on the substrate. In-Sn on Cu has a non-uniform microstructure caused by diffusion of Cu into the solder during sample preparation, with regions of the Sn-rich {gamma} phase imbedded in a matrix of the In-rich {beta} phase. The microstructure of In-Sn on Ni is uniform and lamellar and the two phases are strongly coupled. The solders deform non-uniformly, with deformation concentrating in a band along the length of the sample for Bi-Sn and In-Sn on Cu, though the deformation is more diffuse in In-Sn than in Bi-Sn. Deformation of In-Sn on Ni spreads throughout the width of the joint. The different deformation patterns affect the shape of the stress-strain curves. Stress-strain curves for Bi-Sn and In-Sn on Cu exhibit sharp decays in the engineering stress after reaching a peak. Most of this stress decay is removed for In-Sn on Ni. The creep behavior of In-Sn also depends on the substrate, with the creep deformation controlled by the soft P phase of the eutectic for In-Sn on Cu and controlled by the harder {gamma} phase for In-Sn on Ni. When In-Sn on Ni samples are aged, the microstructure coarsens and changes to an array of {gamma} phase regions in a matrix of the {beta} phase, and the creep behavior changes to resemble that of In-Sn on Cu. The creep behavior of Bi-Sn changes with temperature. Two independent mechanisms operate at lower temperatures, but there is still some question as to whether one or both of these, or a third mechanism, operates at higher temperatures.

Goldstein, J.L.F. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; [Lawrence Berkeley Lab., CA (United States)

1993-11-01T23:59:59.000Z

249

Electromigration kinetics and critical current of Pb-free interconnects  

SciTech Connect (OSTI)

Electromigration kinetics of Pb-free solder bump interconnects have been studied using a single bump parameter sweep technique. By removing bump to bump variations in structure, texture, and composition, the single bump sweep technique has provided both activation energy and power exponents that reflect atomic migration and interface reactions with fewer samples, shorter stress time, and better statistics than standard failure testing procedures. Contact metallurgies based on Cu and Ni have been studied. Critical current, which corresponds to the Blech limit, was found to exist in the Ni metallurgy, but not in the Cu metallurgy. A temperature dependence of critical current was also observed.

Lu, Minhua; Rosenberg, Robert [IBM T. J. Watson Research Center, Yorktown Heights, New York 10598 (United States)

2014-04-07T23:59:59.000Z

250

Au microstructure and the functional properties of Ni/Au finishes on ceramic IC packages  

SciTech Connect (OSTI)

Ni/Au plated finishes used on thick-film metallized multilayer ceramic packages for integrated circuits must meet functional requirements such as bondability, sealability, and solderability. Their ability to do so is dependent, among other things, on the ability of the Au deposit to inhibit the grain boundary diffusion and subsequent surface oxidation of Ni. In this study, the relation between functional performance, Ni diffusionr ate, and Au microstructure was examined. Extent of Ni diffusion during heating was determined by Auger electron spectroscopy for several electrolytic and electroless Ni/Au finishing processes. Results were correlated with differences in Au microstructures determined by SEM, atomic force microscopy, and XRD.

Winters, E.D.; Baxter, W.K. [Coors Electronic Package Co., Chattanooga, TN (United States); Braski, D.N.; Watkins, T.R. [Oak Ridge National Lab., TN (United States)

1995-12-31T23:59:59.000Z

251

Phase 2 of the array automated assembly task for the low cost silicon solar array project. Final report  

SciTech Connect (OSTI)

Studies were conducted on several fundamental aspects of electroless nickel/solder metallization for silicon solar cells. A process proposed by Motorola, which precedes the electroless nickel plating with several steps of palladium plating and heat treatment, was compared directly with single step electroless nickel plating. Work has directed toward answering specific questions concerning the effect of silicon surface oxide on nickel plating, effects of thermal stresses on the metallization, sintering of nickel plated on silicon, and effects of exposure to the plating solution on solar cell characteristics. The Motorola process was compared with simple electroless nickel plating in a series of parallel experiments. Results are presented. (WHK)

Petersen, R.C.

1980-11-01T23:59:59.000Z

252

Material compatibility and thermal aging of thermoelectric materials.  

SciTech Connect (OSTI)

In order to design a thermoelectric (TE) module suitable for long-term elevated temperature use, the Department 8651 has conducted parametric experiments to study material compatibility and thermal aging of TE materials. In addition, a comprehensive material characterization has been preformed to examine thermal stability of P- and N-based alloys and their interaction with interconnect diffusion barrier(s) and solder. At present, we have completed the 7-days aging experiments for 36 tiles, from ambient to 250 C. The thermal behavior of P- and N-based alloys and their thermal interaction with both Ni and Co diffusion barriers and Au-Sn solder were examined. The preliminary results show the microstructure, texture, alloy composition, and hardness of P-(Bi,Sb){sub 2}Te{sub 3} and N-Bi{sub 2}(Te,Se){sub 3} alloys are thermally stable up to 7 days annealing at 250 C. However, metallurgical reactions between the Ni-phosphor barriers and P-type base alloy were evident at temperatures {ge} 175 C. At 250 C, the depth (or distance) of the metallurgical reaction and/or Ni diffusion into P-(Bi,Sb){sub 2}Te{sub 3} is approximately 10-15 {micro}m. This thermal instability makes the Ni-phosphor barrier unsuitable for use at temperatures {ge} 175 C. The Co barrier appeared to be thermally stable and compatible with P(Bi,Sb){sub 2}Te{sub 3} at all annealing temperatures, with the exception of a minor Co diffusion into Au-Sn solder at {ge} 175 C. The effects of Co diffusion on long-term system reliability and/or the thermal stability of the Co barrier are yet to be determined. Te evaporation and its subsequent reaction with Au-Sn solder and Ni and Co barriers on the ends of the tiles at temperatures {ge} 175 C were evident. The Te loss and its effect on the long-term required stoichiometry of P-(Bi, Sb){sub 2}Te{sub 3} are yet to be understood. The aging experiments of 90 days and 180 days are ongoing and scheduled to be completed in 30 days and 150 days, respectively. Material characterization activities are continuing for the remaining tiles.

Gardea, Andrew D.; Nishimoto, Ryan; Yang, Nancy Y. C.; Morales, Alfredo Martin; Whalen, Scott A.; Chames, Jeffrey M.; Clift, W. Miles

2009-09-01T23:59:59.000Z

253

An apparatus for the measurement of thermal conductivity of liquid neon  

E-Print Network [OSTI]

past the max1mum recommended storage temperature of 100 C. The hot plate, Pl, and guard ring, P2, are heated. by nicrome heater wires, whose respective resistances are 50 ohms and. 150 ohms. An additional heater of 5 ohms was placed near the cupro-nickel.... to the heater. They were coiled around the top of the guard. ring once before being soldered to the number 36 copper wires leading to the top plate. The number 36 wires go to the top plate by means of a 1/8 in. cupro-nickel tube and were sealed from...

Jensen, Jerald Norman

1967-01-01T23:59:59.000Z

254

Direct cooled power electronics substrate  

DOE Patents [OSTI]

The disclosure describes directly cooling a three-dimensional, direct metallization (DM) layer in a power electronics device. To enable sufficient cooling, coolant flow channels are formed within the ceramic substrate. The direct metallization layer (typically copper) may be bonded to the ceramic substrate, and semiconductor chips (such as IGBT and diodes) may be soldered or sintered onto the direct metallization layer to form a power electronics module. Multiple modules may be attached to cooling headers that provide in-flow and out-flow of coolant through the channels in the ceramic substrate. The modules and cooling header assembly are preferably sized to fit inside the core of a toroidal shaped capacitor.

Wiles, Randy H [Powell, TN; Wereszczak, Andrew A [Oak Ridge, TN; Ayers, Curtis W. (Kingston, TN) [Kingston, TN; Lowe, Kirk T. (Knoxville, TN) [Knoxville, TN

2010-09-14T23:59:59.000Z

255

Operational Amplifier General Description  

E-Print Network [OSTI]

of soldering surface mount devices. ESD Tolerance (Note 8) 400V 400V 400V Electrical Characteristics (Note 5V Average Input Offset 15 ĀµV/Ā°C Voltage Drift Input Offset Voltage TA = 25Ā°C, VS = Ā±20V Ā±10 Ā±15 Ā±15 m TAMAX 0.210 1.5 0.8 ĀµA Input Resistance TA = 25Ā°C, VS = Ā±20V 1.0 6.0 0.3 2.0 0.3 2.0 M TAMIN TA TAMAX

Wedeward, Kevin

256

Magnetically attached sputter targets  

DOE Patents [OSTI]

An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

Makowiecki, D.M.; McKernan, M.A.

1994-02-15T23:59:59.000Z

257

Method of fabricating a solar cell array  

DOE Patents [OSTI]

A first set of pre-tabbed solar cells are assembled in a predetermined array with at least part of each tab facing upward, each tab being fixed to a bonding pad on one cell and abutting a bonding pad on an adjacent cell. The cells are held in place with a first vacuum support. The array is then inverted onto a second vacuum support which holds the tabs firmly against the cell pads they abut. The cells are exposed to radiation to melt and reflow the solder pads for bonding the tab portions not already fixed to bonding pads to these pads.

Lazzery, Angelo G. (Oaklyn, NJ); Crouthamel, Marvin S. (Pennsauken, NJ); Coyle, Peter J. (Oaklyn, NJ)

1982-01-01T23:59:59.000Z

258

Laminated photovoltaic modules using back-contact solar cells  

DOE Patents [OSTI]

Photovoltaic modules which comprise back-contact solar cells, such as back-contact crystalline silicon solar cells, positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The module designs allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

Gee, James M. (Albuquerque, NM); Garrett, Stephen E. (Albuquerque, NM); Morgan, William P. (Albuquerque, NM); Worobey, Walter (Albuquerque, NM)

1999-09-14T23:59:59.000Z

259

Method of monolithic module assembly  

DOE Patents [OSTI]

Methods for "monolithic module assembly" which translate many of the advantages of monolithic module construction of thin-film PV modules to wafered c-Si PV modules. Methods employ using back-contact solar cells positioned atop electrically conductive circuit elements affixed to a planar support so that a circuit capable of generating electric power is created. The modules are encapsulated using encapsulant materials such as EVA which are commonly used in photovoltaic module manufacture. The methods of the invention allow multiple cells to be electrically connected in a single encapsulation step rather than by sequential soldering which characterizes the currently used commercial practices.

Gee, James M. (Albuquerque, NM); Garrett, Stephen E. (Albuquerque, NM); Morgan, William P. (Albuquerque, NM); Worobey, Walter (Albuquerque, NM)

1999-01-01T23:59:59.000Z

260

Repairable chip bonding/interconnect process  

DOE Patents [OSTI]

A repairable, chip-to-board interconnect process which addresses cost and testability issues in the multi-chip modules. This process can be carried out using a chip-on-sacrificial-substrate technique, involving laser processing. This process avoids the curing/solvent evolution problems encountered in prior approaches, as well is resolving prior plating problems and the requirements for fillets. For repairable high speed chip-to-board connection, transmission lines can be formed on the sides of the chip from chip bond pads, ending in a gull wing at the bottom of the chip for subsequent solder.

Bernhardt, Anthony F. (Berkeley, CA); Contolini, Robert J. (Livermore, CA); Malba, Vincent (Livermore, CA); Riddle, Robert A. (Tracy, CA)

1997-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Repairable chip bonding/interconnect process  

DOE Patents [OSTI]

A repairable, chip-to-board interconnect process which addresses cost and testability issues in the multi-chip modules is disclosed. This process can be carried out using a chip-on-sacrificial-substrate technique, involving laser processing. This process avoids the curing/solvent evolution problems encountered in prior approaches, as well is resolving prior plating problems and the requirements for fillets. For repairable high speed chip-to-board connection, transmission lines can be formed on the sides of the chip from chip bond pads, ending in a gull wing at the bottom of the chip for subsequent solder. 10 figs.

Bernhardt, A.F.; Contolini, R.J.; Malba, V.; Riddle, R.A.

1997-08-05T23:59:59.000Z

262

Electron tunneling studies of Mn12-Acetate  

E-Print Network [OSTI]

]. . . . . . . . . . . . . . . . 24 10 Frame for rotating the tunneling wires in the PLD chamber during deposition. The two black posts are brass that were wrapped with shrink tubing so that the wires can be attached to them and still be insulated from one another. The two white... copper posts that are made from 0.010” diameter bare copper wires. The tunneling wires are first wrapped around the copper posts and then fixed in position with PbSn solder. Although silver print and silver epoxy have also been used to connect the wires...

Ma, Lianxi

2008-10-10T23:59:59.000Z

263

Design of a Probe for Strain Sensitivity Studies of Critical Current Densities in SC Wires and Tapes  

SciTech Connect (OSTI)

The design of a variable-temperature probe used to perform strain sensitivity measurements on LTS wires and HTS wires and tapes is described. The measurements are intended to be performed at liquid helium temperatures (4.2 K). The wire or tape to be measured is wound and soldered on to a helical spring device, which is fixed at one end and subjected to a torque at the free end. The design goal is to be able to achieve {+-} 0.8 % strain in the wire and tape. The probe is designed to carry a current of 2000A.

Dhanaraj, N.; Barzi, E.; Turrioni, D.; Rusy, A.; Lombardo, V.; /Fermilab

2011-07-01T23:59:59.000Z

264

Solicitations | Department of Energy  

Energy Savers [EERE]

AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page on Google Bookmark EERE: Alternative Fuels Data Center Home Page on Office of Inspector GeneralDepartment of Energyof the Americas |DOEEnergy SmoothSolar IndustrySB 2SolarSolder

265

Experimental studies of helical solenoid model based on YBCO tape-bridge joints  

SciTech Connect (OSTI)

Helical solenoids that provide solenoid, helical dipole and helical gradient field components are designed for a helical cooling channel (HCC) proposed for cooling of muon beams in a muon collider. The high temperature superconductor (HTS), 12 mm wide and 0.1 mm thick YBCO tape, is used as the conductor for the highest-field section of HCC due to certain advantages, such as its electrical and mechanical properties. To study and address the design, and technological and performance issues related to magnets based on YBCO tapes, a short helical solenoid model based on double-pancake coils was designed, fabricated and tested at Fermilab. Splicing joints were made with Sn-Pb solder as the power leads and the connection between coils, which is the most critical element in the magnet that can limit the performance significantly. This paper summarizes the test results of YBCO tape and double-pancake coils in liquid nitrogen and liquid helium, and then focuses on the study of YBCO splices, including the soldering temperatures and pressures, and splice bending test.

Yu, M.; Lombardo, V.; Turrioni, D.; Zlobin, A.V.; /Fermilab; Flangan, G.; /MUONS Inc., Batavia; Lopes, M.L.; /Fermilab; Johnson, R.P.; /Fermilab

2011-06-01T23:59:59.000Z

266

Corrosion inhibitors in the electronic industry  

SciTech Connect (OSTI)

The most widely used inhibitors in the electronics industry are chromates, phosphates, and silicates in chip processing and azoles in printed circuit board (PCB) fabrication. Azoles are the principal constituents of Organic Solderability Preservatives (OSPS) used on bare copper that could replace Hot Air Solder Leveling (HASL). For years HASL has been the most prevalent surface finishing process in PCB fabrication. This process is currently under scrutiny, because of safety and environment concerns (lead exposure, waste disposal), process limitations (stress, extendibility to fine-pitch device assembly), and cost. The use of azoles is a cost-effective solution to these concerns but it is also a source of new ones. Aside from being typical corrosion inhibitors, the azoles are expected to provide protection to a copper surface against thermal oxidation yet at higher temperatures inhibitors themselves are not stable. The challenge of bringing azoles to PCB manufacture has resulted in close interaction of the board shop, assembly customer, and the OSP chemistry suppliers. This paper is an overview of the relevant work in which a compromise between process demands and achievable inhibitor performance is discussed.

Brusic, V. [IBM, Yorktown Heights, NY (United States). Thomas J. Watson Research Center

1996-12-01T23:59:59.000Z

267

In-depth survey report: Control technology for small business: Evaluation of a flexible duct ventilation system for radiator repair, at A-1 Radiator, Reno, Nevada  

SciTech Connect (OSTI)

An engineering control evaluation was conducted at a radiator repair shop which operated at a very high level of production. The shop had the potential for high exposures to lead (7439921) because of the high volume of work, the number of radiator repair stations, and repairs to huge radiators for mining equipment. Local exhaust ventilation which utilized adjustable arm elephant trunk exhaust hoods had been installed 18 months prior to the visit. The objective of the study was to evaluate the effectiveness of the local exhaust ventilation (LEV) system to control lead exposures during work operations. Time weighted average personal exposures for lead were at or below the OSHA permissible exposure level for ten of 15 mechanics during a high level of production. The elephant trunk ventilation system was capable of controlling lead fumes while shop doors were open, except at one tank in a corner. Work practices were found to be a source of excessive lead exposure. Emissions from a worker's own soldering and from soldering activity upwind of the worker were a major source of lead exposure. Collapse of flexible portions of ducts could reduce exhaust volume. Dampers also showed a tendency to close automatically.

Sheehy, J.W.; Cooper, T.C.; Hall, R.M.; Meier, R.M.

1990-02-01T23:59:59.000Z

268

Electrical and thermal finite element modeling of arc faults in photovoltaic bypass diodes.  

SciTech Connect (OSTI)

Arc faults in photovoltaic (PV) modules have caused multiple rooftop fires. The arc generates a high-temperature plasma that ignites surrounding materials and subsequently spreads the fire to the building structure. While there are many possible locations in PV systems and PV modules where arcs could initiate, bypass diodes have been suspected of triggering arc faults in some modules. In order to understand the electrical and thermal phenomena associated with these events, a finite element model of a busbar and diode was created. Thermoelectrical simulations found Joule and internal diode heating from normal operation would not normally cause bypass diode or solder failures. However, if corrosion increased the contact resistance in the solder connection between the busbar and the diode leads, enough voltage potentially would be established to arc across micron-scale electrode gaps. Lastly, an analytical arc radiation model based on observed data was employed to predicted polymer ignition times. The model predicted polymer materials in the adjacent area of the diode and junction box ignite in less than 0.1 seconds.

Bower, Ward Isaac; Quintana, Michael A.; Johnson, Jay

2012-01-01T23:59:59.000Z

269

Process research on Semix Silicon Material (PROSSM). Quarterly report No. 5, December 1, 1981-February 28, 1982  

SciTech Connect (OSTI)

Emphasis was shifted from the development of a cost-effective process sequence to research designed to understand the mechanisms of photovoltaic conversion in semicrystalline silicon. With this change has gone a change of title from Module Experimental Process System Development Unit (MEPSDU) to Process Research of Semix Silicon Material (PROSSM). Efforts are now underway to prepare a revised program plan with emphasis on determining the mechanisms limiting voltage and current collection in the semicrystalline silicon. The efforts reported concern work done before the change in emphasis and so the continued development of the cost-effective process sequence is reported. A cost-effective process sequence was identified, equipment was designed to implement a 6.6 MW per year automated production line, and a cost analysis projected a $0.56 per watt cell add-on cost for this line. Four process steps were developed for this program: glass bead back clean-up; hot spray antireflective coating; wave-soldering of fronts; ion milling for edging. While spray dopants were advertised as an off the shelf developed product, they proved to be unreliable with shorter than advertised shelf life. Equipment for handling and processing solar cells is available for all of the cell processing steps identified in this program. During this quarter efforts included work on spray dopant, edging, AR coating, wave soldering and fluxing, ion milling and cost analysis.

Wohlgemuth, J H; Warfield, D B

1982-01-01T23:59:59.000Z

270

Development of a Fluxless Flip Chip Bonding Process for Optical Military Electronics  

SciTech Connect (OSTI)

As military electronics tend to become lighter, smaller, thinner, and lower cost, the use of flip chip technology is becoming more common place to meet system requirements, yet survive environments. This paper explores the development of an optical flip chip application and details the selection/qualification of the substrate. The selected assembly consists of a procured 1x12 Vertical Cavity Surface Emitting Laser (VCSEL) die, having 80um diameter eutectic AuSn solder bumps at 250um pitch and flip chip bonded to a .006” thick 99.6% alumina substrate with .006” diameter thru holes and metallized with 500Å WTi, under minimum 2.0-3.0?m (80-120?”) thin film deposited Au. An 8 run, 3 factor, 2 level Full Factorial Design of Experiments (DOE) was completed on procured detector arrays and procured ceramic substrates using the Suss Microtec FC150. The optimum settings for the peak temperature, peak time and final die z-height were selected using the ANOVA results and interaction plots. Additional studies were completed to qualify in-house produced substrates. An epoxy glob-top encapsulant was selected to dissipate stress on the flip chip solder joints and to enhance thermal shock performance.

Girardi, Michael

2007-11-11T23:59:59.000Z

271

Micromechanical die attachment surcharge  

DOE Patents [OSTI]

An attachment structure is disclosed for attaching a die to a supporting substrate without the use of adhesives or solder. The attachment structure, which can be formed by micromachining, functions purely mechanically in utilizing a plurality of shaped pillars (e.g. round, square or polygonal and solid, hollow or slotted) that are formed on one of the die or supporting substrate and which can be urged into contact with various types of mating structures including other pillars, a deformable layer or a plurality of receptacles that are formed on the other of the die or supporting substrate, thereby forming a friction bond that holds the die to the supporting substrate. The attachment structure can further include an alignment structure for precise positioning of the die and supporting substrate to facilitate mounting the die to the supporting substrate. The attachment structure has applications for mounting semiconductor die containing a microelectromechanical (MEM) device, a microsensor or an integrated circuit (IC), and can be used to form a multichip module. The attachment structure is particularly useful for mounting die containing released MEM devices since these devices are fragile and can otherwise be damaged or degraded by adhesive or solder mounting.

Filter, William F. (Albuquerque, NM); Hohimer, John P. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

272

Printed wiring board fabrication and lead elimination via single-bath electrodeposition  

SciTech Connect (OSTI)

Printed wiring board (PWB) fabrication, an operation performed both at LLNL and throughout the electronics industry, generates considerable quantities of hazardous waste, notably lead-bearing materials used for soldering, tinning, and finish coating the circuits of the board. Hot-air solder leveling (HASL), the most common method of finishing is one of the main sources of hazardous lead-bearing wastes in traditional PWB manufacturing. The development of a safer finishing method will lead to employee health and environmental benefits. In addition, there is a production advantage to eliminating HASL, for it provides a fairly uneven surface that is problematic for mounting very small components. In this project, we developed ''single-bath electroplating'' as a potential HASL replacement technology for many applications. Single-bath electroplating involves alternating deposition of one or the other metal component of a bimetal bath, through control of plating potential and mass transport. It employs a nickel layer as both etch resist and finish coat and has the potential for lowering environmental and human-health risks associated with PWB manufacture--while at the same time reconfiguring the process for greater efficiency and profitability.

Meltzer, M P; Steffani, C P

2001-02-21T23:59:59.000Z

273

Robustness and Versatility of Thin Films on Low Temperature Cofired Ceramic (LTCC)  

SciTech Connect (OSTI)

Thin film multilayers have previously been introduced on multilayer low temperature cofired ceramic (LTCC). The ruggedness of a multipurpose Ti-Cu-Pt-Au stack has continued to benefit fabrication and reliability in state-of-theart modules. Space optimization is described, preserving miniaturization of critical spaces and component pads. Additional soldering details are also presented, including trends with solder-stop materials. Feature compensation becomes a simple step in the normal manufacturing flow which enables exact targeting of desired feature sizes. In addition, fine details of the manufacturing process, including ion milling, will be discussed. We will discuss full long-term aging results and structural details that reinforce the reliability and function. Different thin film materials for specific applications can be exploited for additional capabilities such as filters and other integral components. Cross sections verify the results shown. This successful integration of thin films on LTCC points to higher frequencies which require finer lines and spaces. Advancements of these applications become possible due to the associated progression of smaller skin depth and thinner metallic material.

Wolf, J. Ambrose; Vianco, P. T.; Johnson, M. H.; Goldammer, S.

2011-10-09T23:59:59.000Z

274

Effect of compressive and tensile strains on the critical current density of liquid-phase diffusion processed Nb{sub 3}Sn  

SciTech Connect (OSTI)

The influence of strain on the critical current density of liquid-phase diffusion processed Nb{sub 3}Sn foil has been examined. Eight different levels of plane stress were applied to the Nb{sub 3}Sn by using differential thermal contraction. This differential thermal contraction was achieved by soldering Nb{sub 3}Sn foil samples between two plates of eight different materials, and cooling the composite structures from the soldering temperature to the test temperature. Brass, copper, stainless steel, Hastelloy X, Inconel 600, nickel, niobium and tungsten plates were used. In addition, bending strains were applied to the Nb{sub 3}Sn foil using a non-symmetric bi-metal structure with a brass or niobium plate placed in a bending fixture. In a transverse field of 5T and at a test temperature of 4.2 K, a thermally applied axial strain of 0.4% increased the critical current by 60%. An axial tensile bending strain of the same magnitude resulted in a critical current increase of only about 9%. These results will be discussed and compared to observations in the literature for solid-phase diffusion processed Nb{sub 3}Sn.

Murray, M.L.; Benz, M.G.; Zabala, R.J.; Raber, T.R. [General Electric Research and Development Center, Schenectady, NY (United States)

1994-12-31T23:59:59.000Z

275

Twenty years of service at NBNM - Analysis of Spectrolab module  

SciTech Connect (OSTI)

This study of adhesional strength and surface analysis of encapsulant and silicon cell samples from a Natural Bridges National Monument (NBNM) Spectrolab module is an attempt to understand from its success. The module was fabricated using polyvinyl butyral (PVB) as an encapsulant. The average adhesional shear strength of the encapsulant at the cell/encapsulant interface in this module was 4.51 MPa or {approximately} 18% lower than that in currently manufactured modules. Typical encapsulant surface composition was as follows: C 75.0 at.% O 23.2 at.%, and Si 1.6 at.%, with Ag {approximately}0.2 at.% and Pb {approximately} 0.5 at.% with some tin respectively over the grid lines and solder bond. Representative silicon cell surface composition was: K 1.4 at.%, C 20.8 at.%, Sn 0.94 at.%, O 15.1 at.%, Na 2.7 at.% and Si 59.0 at.%. The presence of tin detected on the silicon cell surface may be attributed to corrosion of solder bond. The module differs from typical contemporary modules in the use of PVB, metallic mesh type interconnection, and silicon oxide AR coating.

DHERE,N.G.; PANDIT,M.B.; GHONGADI,S.R.; QUINTANA,MICHAEL A.; KING,DAVID L.; KRATOCHVIL,JAY A.

2000-04-11T23:59:59.000Z

276

Die Materials for Critical Applications and Increased Production Rates  

SciTech Connect (OSTI)

Die materials for aluminum die-casting need to be resistant to heat checking, and have good resistance to washout and to soldering in a fast flow of molten aluminum. To resist heat checking, die materials should have a low coefficient of thermal expansion, high thermal conductivity, high hot yield strength, good temper softening resistance, high creep strength, and adequate ductility. To resist the washout and soldering, die materials should have high hot hardness, good temper resistance, low solubility in molten aluminum and good oxidation resistance. It is difficult for one material to satisfy with all above requirements. In practice, H13 steel is the most popular material for aluminum die casting dies. While it is not an ideal choice, it is substantially less expensive to use than alternative materials. However, in very demanding applications, it is sometimes necessary to use alternative materials to ensure a reasonable die life. Copper-base, nickel-base alloys and superalloys, titanium-,molybdenum-, tungsten-base alloys, and to some extent yttrium and niobium alloys, have all been considered as potential materials for demanding die casting applications. Most of these alloys exhibit superior thermal fatigue resistance, but suffer from other shortcomings.

David Schwam; John Wallace; Sebastian Birceanu

2002-11-30T23:59:59.000Z

277

Ferroelectric and ferromagnetic properties in BaTiO{sub 3} thin films on Si (100)  

SciTech Connect (OSTI)

In this paper, we report on the epitaxial integration of room temperature lead-free ferroelectric BaTiO{sub 3} thin (?1050?nm) films on Si (100) substrates by pulsed laser deposition technique through a domain matching epitaxy paradigm. We employed MgO and TiN as buffer layers to create BaTiO{sub 3}/SrRuO{sub 3}/MgO/TiN/Si (100) heterostructures. C-axis oriented and cube-on-cube epitaxial BaTiO{sub 3} is formed on Si (100) as evidenced by the in-plane and out-of-plane x-ray diffraction, and transmission electron microscopy. X-ray photoemission spectroscopic measurements show that Ti is in 4(+) state. Polarization hysteresis measurements together with Raman spectroscopy and temperature-dependent x-ray diffraction confirm the room temperature ferroelectric nature of BaTiO{sub 3}. Furthermore, laser irradiation of BaTiO{sub 3} thin film is found to induce ferromagnetic-like behavior but affects adversely the ferroelectric characteristics. Laser irradiation induced ferromagnetic properties seem to originate from the creation of oxygen vacancies, whereas the pristine BaTiO{sub 3} shows diamagnetic behavior, as expected. This work has opened up the route for the integration of room temperature lead-free ferroelectric functional oxides on a silicon platform.

Singamaneni, Srinivasa Rao, E-mail: ssingam@ncsu.edu; Prater, John T. [Materials Science Division, Army Research Office, Research Triangle Park, North Carolina 27709 (United States); Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States); Punugupati, Sandhyarani; Hunte, Frank; Narayan, Jagdish [Department of Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

2014-09-07T23:59:59.000Z

278

Thin-film chip-to-substrate interconnect and methods for making same  

DOE Patents [OSTI]

Integrated circuit chips are electrically connected to a silica wafer interconnection substrate. Thin film wiring is fabricated down bevelled edges of the chips. A subtractive wire fabrication method uses a series of masks and etching steps to form wires in a metal layer. An additive method direct laser writes or deposits very thin metal lines which can then be plated up to form wires. A quasi-additive or subtractive/additive method forms a pattern of trenches to expose a metal surface which can nucleate subsequent electrolytic deposition of wires. Low inductance interconnections on a 25 micron pitch (1600 wires on a 1 cm square chip) can be produced. The thin film hybrid interconnect eliminates solder joints or welds, and minimizes the levels of metallization. Advantages include good electrical properties, very high wiring density, excellent backside contact, compactness, and high thermal and mechanical reliability.

Tuckerman, David B. (Livermore, CA)

1991-01-01T23:59:59.000Z

279

Thin-film chip-to-substrate interconnect and methods for making same  

DOE Patents [OSTI]

Integrated circuit chips are electrically connected to a silicon wafer interconnection substrate. Thin film wiring is fabricated down bevelled edges of the chips. A subtractive wire fabrication method uses a series of masks and etching steps to form wires in a metal layer. An additive method direct laser writes or deposits very thin lines which can then be plated up to form wires. A quasi-additive or subtractive/additive method forms a pattern of trenches to expose a metal surface which can nucleate subsequent electrolytic deposition of wires. Low inductance interconnections on a 25 micron pitch (1600 wires on a 1 cm square chip) can be produced. The thin film hybrid interconnect eliminates solder joints or welds, and minimizes the levels of metallization. Advantages include good electrical properties, very high wiring density, excellent backside contact, compactness, and high thermal and mechanical reliability. 6 figs.

Tuckerman, D.B.

1988-06-06T23:59:59.000Z

280

Low thermal resistance power module assembly  

DOE Patents [OSTI]

A power module assembly with low thermal resistance and enhanced heat dissipation to a cooling medium. The assembly includes a heat sink or spreader plate with passageways or openings for coolant that extend through the plate from a lower surface to an upper surface. A circuit substrate is provided and positioned on the spreader plate to cover the coolant passageways. The circuit substrate includes a bonding layer configured to extend about the periphery of each of the coolant passageways and is made up of a substantially nonporous material. The bonding layer may be solder material which bonds to the upper surface of the plate to provide a continuous seal around the upper edge of each opening in the plate. The assembly includes power modules mounted on the circuit substrate on a surface opposite the bonding layer. The power modules are positioned over or proximal to the coolant passageways.

Hassani, Vahab (Denver, CO); Vlahinos, Andreas (Castle Rock, CO); Bharathan, Desikan (Arvada, CO)

2007-03-13T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
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We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Electrochemical Approaches to PV Busbar Application  

SciTech Connect (OSTI)

Busbars are an integral component of any thin-film photovoltaic module and must be easy and quick to apply by PV manufacturers, as well as provide long-term reliability in deployed modules. Potential reliability issues include loss of adhesion and delamination, chemical instability under current collection conditions (electromigration or corrosion), compatibility of material and application method with subsequent encapsulation steps. Several new and novel busbar materials and application methods have been explored, including adhering metal busbars with various one- and two-part conductive epoxies or conductive adhesive films, ultrasonic bonding of metal busbar strips, and bonding of busbar strips using low-temperature solders. The most promising approach to date has been the direct application of metal busbars via various electrochemical techniques, which offers a variety of distinct advantages.

Pankow, J. W.

2005-01-01T23:59:59.000Z

282

ES&H development activities for the W89 warhead  

SciTech Connect (OSTI)

Environmental, Safety and Health (ES&H) issues became an important design consideration during the development of the W89 warhead for the SRAM 11 (Short-Range Attack Missile) missile. An action plan was developed to handle these issues at all the production agencies and at both the system and the component level. The main thrust was in the area of solvent substitution, in particular for solder flux removal. The cleaner d-limonene followed by an isopropyl alcohol rinse was selected for applications were the traditional cleaners were 1,1,1 trichloroethane or trichloroethylene. Compatibility testing rather than efficacy testing dominated the development effort. In addition to other solvent substitution applications, organic materials that were free of toluene diisocynate (TDI), and methylene dianiline (MDA) were explored for use in the W89.

Pretzel, C.W.

1995-08-01T23:59:59.000Z

283

Capillary test specimen, system, and methods for in-situ visualization of capillary flow and fillet formation  

DOE Patents [OSTI]

A capillary test specimen, method, and system for visualizing and quantifying capillary flow of liquids under realistic conditions, including polymer underfilling, injection molding, soldering, brazing, and casting. The capillary test specimen simulates complex joint geometries and has an open cross-section to permit easy visual access from the side. A high-speed, high-magnification camera system records the location and shape of the moving liquid front in real-time, in-situ as it flows out of a source cavity, through an open capillary channel between two surfaces having a controlled capillary gap, and into an open fillet cavity, where it subsequently forms a fillet on free surfaces that have been configured to simulate realistic joint geometries. Electric resistance heating rapidly heats the test specimen, without using a furnace. Image-processing software analyzes the recorded images and calculates the velocity of the moving liquid front, fillet contact angles, and shape of the fillet's meniscus, among other parameters.

Hall, Aaron C. (Albuquerque, NM); Hosking, F. Michael (Albuquerque, NM),; Reece, Mark (Albuquerque, NM)

2003-06-24T23:59:59.000Z

284

Feed mechanism and method for feeding minute items  

DOE Patents [OSTI]

A feeding mechanism and method for feeding minute items, such as capacitors, resistors, or solder preforms. The mechanism is adapted to receive a plurality of the randomly-positioned and randomly-oriented extremely small or minute items, and to isolate, orient, and position the items in a specific repeatable pickup location wherefrom they may be removed for use by, for example, a computer-controlled automated assembly machine. The mechanism comprises a sliding shelf adapted to receive and support the items; a wiper arm adapted to achieve a single even layer of the items; and a pushing arm adapted to push the items into the pickup location. The mechanism can be adapted for providing the items with a more exact orientation, and can also be adapted for use in a liquid environment.

Stringer, Timothy Kent; Yerganian, Simon Scott

2012-11-06T23:59:59.000Z

285

Release Resistant Electrical Interconnections For Mems Devices  

DOE Patents [OSTI]

A release resistant electrical interconnection comprising a gold-based electrical conductor compression bonded directly to a highly-doped polysilicon bonding pad in a MEMS, IMEMS, or MOEMS device, without using any intermediate layers of aluminum, titanium, solder, or conductive adhesive disposed in-between the conductor and polysilicon pad. After the initial compression bond has been formed, subsequent heat treatment of the joint above 363 C creates a liquid eutectic phase at the bondline comprising gold plus approximately 3 wt % silicon, which, upon re-solidification, significantly improves the bond strength by reforming and enhancing the initial bond. This type of electrical interconnection is resistant to chemical attack from acids used for releasing MEMS elements (HF, HCL), thereby enabling the use of a "package-first, release-second" sequence for fabricating MEMS devices. Likewise, the bond strength of an Au--Ge compression bond may be increased by forming a transient liquid eutectic phase comprising Au-12 wt % Ge.

Peterson, Kenneth A. (Albuquerque, NM); Garrett, Stephen E. (Albuquerque, NM); Reber, Cathleen A. (Corrales, NM)

2005-02-22T23:59:59.000Z

286

Characterization of printing and laser trimming of DuPont 2000 series resistors on DuPont 951 {open_quotes}Green Tape{trademark}{close_quotes}  

SciTech Connect (OSTI)

DuPont 2000 series resistors were reviewed and found to come closest to our requirement of 1% resistor tolerance over the expected 30-year life of our products. The evaluation performed involved the characterization of both the printing and trimming processes. The printing process was characterized for firing temperature print thickness, print direction, resistor geometry and encapsulant effect. Laser trimming was characterized by first finding an operating envelope and then selecting an operating point. The envelope was located by varying the trimming parameters and determining their acceptability to electrical and visual criteria. Samples from both the envelope and operating point were environmentally conditioned The conditioning included thermal shock temperature cycle, 1000-hour temperature aging, 1000-hour humidity aging, and a simulated gold/tin solder reflow.

Morgenstern, H.; Bandler, S.; Barner, G.

1996-10-01T23:59:59.000Z

287

Dr. John J. Stephens, Jr., metallurgist extraordinaire.  

SciTech Connect (OSTI)

The organizers of the Dr. John J. Stephens, Jr. Memorial Symposium: Deformation and Interfacial Phenomena in Advanced High-Temperature Materials are honoring the memory of Dr. Stephens and his many technical contributions that were accomplished over a relatively brief twenty year career. His research spanned the areas of creep and deformation of metals, dispersion-strengthened alloys and their properties, metal matrix composite materials, processing and properties of refractory metals, joining of ceramic-ceramic and metal-ceramic systems, active braze alloy development, and mechanical modeling of soldered and brazed assemblies. The purpose of this presentation is to highlight his research and engineering accomplishments, particularly during his professional career at Sandia National Laboratories in Albuquerque, NM.

Hosking, Floyd Michael

2010-10-01T23:59:59.000Z

288

Effect of Dielectric Selection on Sintering Behavior of LTCC  

SciTech Connect (OSTI)

Low Temperature Cofired Ceramic (LTCC) is a versatile ceramic packaging technology. LTCC’s functionality and performance can be enhanced with the incorporation of passive devices such as resistors, capacitors, and inductors into the structure of the substrate. This incorporation, which eliminates surface mount solder joints is desirable for improving system reliability and allows for increased package density. Commercially available dielectrics for embedding capacitors into LTCC are limited and the incorporation of such systems into LTCC substrates poses processing challenges related to material compatibility. This paper will review multiple dielectric systems and techniques for embedding capacitors into LTCC as well as present new data related to the cofiring behavior of LTCC and custom dielectrics.

Krueger, Daniel S.; Agee, Laura; Fadner, Cristie; Duncan, J. Brent

2010-11-02T23:59:59.000Z

289

Probabilistic Mechanical Reliability Prediction of Thermoelectric Legs  

SciTech Connect (OSTI)

The probability of failure, Pf, for various square-arrayed thermoelectric device designs using bismuth telluride, lead telluride, or skutterudite thermoelectric materials were estimated. Only volume- or bulk-based Pf analysis was considered in this study. The effects of the choice of the thermoelectric material, the size of the leg array, the height of the thermoelectric legs, and the boundary conditions on the Pf of thermoelectric devices were investigated. Yielding of the solder contacts and mounting layer was taken into account. The modeling results showed that the use of longer legs, using skutterudites, allowing the thermoelectric device to freely deform while under a thermal gradient, and using smaller arrays promoted higher probabilities of survival.

Jadaan, Osama M. [University of Wisconsin, Platteville; Wereszczak, Andrew A [ORNL

2009-05-01T23:59:59.000Z

290

Fan-fold shielded electrical leads  

DOE Patents [OSTI]

Disclosed are fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate. 3 figs.

Rohatgi, R.R.; Cowan, T.E.

1996-06-11T23:59:59.000Z

291

Method for fabricating fan-fold shielded electrical leads  

DOE Patents [OSTI]

Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate. 3 figures.

Rohatgi, R.R.; Cowan, T.E.

1994-12-27T23:59:59.000Z

292

Feed mechanism and method for feeding minute items  

DOE Patents [OSTI]

A feeding mechanism and method for feeding minute items, such as capacitors, resistors, or solder preforms. The mechanism is adapted to receive a plurality of the randomly-positioned and randomly-oriented extremely small or minute items, and to isolate, orient, and position one or more of the items in a specific repeatable pickup location wherefrom they may be removed for use by, for example, a computer-controlled automated assembly machine. The mechanism comprises a sliding shelf adapted to receive and support the items; a wiper arm adapted to achieve a single even layer of the items; and a pushing arm adapted to push the items into the pickup location. The mechanism can be adapted for providing the items with a more exact orientation, and can also be adapted for use in a liquid environment.

Stringer, Timothy Kent (Bucyrus, KS); Yerganian, Simon Scott (Lee's Summit, MO)

2009-10-20T23:59:59.000Z

293

Method for fabricating fan-fold shielded electrical leads  

DOE Patents [OSTI]

Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate.

Rohatgi, Rajeev R. (Mountain View, CA); Cowan, Thomas E. (Livermore, CA)

1994-01-01T23:59:59.000Z

294

Fan-fold shielded electrical leads  

DOE Patents [OSTI]

Fan-folded electrical leads made from copper cladded Kapton, for example, with the copper cladding on one side serving as a ground plane and the copper cladding on the other side being etched to form the leads. The Kapton is fan folded with the leads located at the bottom of the fan-folds. Electrical connections are made by partially opening the folds of the fan and soldering, for example, the connections directly to the ground plane and/or the lead. The fan folded arrangement produces a number of advantages, such as electrically shielding the leads from the environment, is totally non-magnetic, and has a very low thermal conductivity, while being easy to fabricate.

Rohatgi, Rajeev R. (Mountain View, CA); Cowan, Thomas E. (Livermore, CA)

1996-01-01T23:59:59.000Z

295

Boron-copper neutron absorbing material and method of preparation  

DOE Patents [OSTI]

A composite, copper clad neutron absorbing material is comprised of copper powder and boron powder enriched with boron 10. The boron 10 content can reach over 30 percent by volume, permitting a very high level of neutron absorption. The copper clad product is also capable of being reduced to a thickness of 0.05 to 0.06 inches and curved to a radius of 2 to 3 inches, and can resist temperatures of 900.degree. C. A method of preparing the material includes the steps of compacting a boron-copper powder mixture and placing it in a copper cladding, restraining the clad assembly in a steel frame while it is hot rolled at 900.degree. C. with cross rolling, and removing the steel frame and further rolling the clad assembly at 650.degree. C. An additional sheet of copper can be soldered onto the clad assembly so that the finished sheet can be cold formed into curved shapes.

Wiencek, Thomas C. (Bolingbrook, IL); Domagala, Robert F. (Indian Head Park, IL); Thresh, Henry (Palos Hts., IL)

1991-01-01T23:59:59.000Z

296

Relative Lifetime Prediction for CPV Die-Attach Layers: Preprint  

SciTech Connect (OSTI)

In concentrating photovoltaics (CPV) cell assemblies, a large-area die-attach layer is subjected to thermal cycles, leading to thermomechanical fatigue. This causes cracking and the eventual failure of the CPV cell by thermal runaway. We define a damage metric representing lumped progress toward failure and present a numerical model for computing the accumulation of damage for arbitrary transient temperature conditions. The model is applied to a particular design with a solder die-attach layer. We show that accelerated-test thermal cycles with higher ramp rates cause more damage, both per cycle and per unit time. Outdoor exposure to one entire year in two geographic locations is also simulated, revealing that a year of exposure in Golden, Colorado is equivalent to 1.4 years of exposure in Oak Ridge, Tennessee.

Silverman, T. J.; Bosco, N.; Kurtz, S.

2012-03-01T23:59:59.000Z

297

The Electrical Resistance of Rutherford-Type Superconducting Cable Splices  

E-Print Network [OSTI]

The electrical resistance of Large Hadron Collider main busbar cable lap splices produced by soft soldering has been measured with two independent methods as a function of intercable contact area and for splices made of cables with various defects. For defect-free lap splices, the resistance increases from 0.3 to 10 n? (at 4.3 K in self-field) when reducing the cable overlap length from 120 to 3 mm, as expected assuming that the resistance is inversely proportional to the intercable contact area. The resistance of bridge splices that connect side-by-side cables can be predicted from the lap splice resistances and the overlap areas involved.

Heck, C; Fleiter, J; Bottura, L

2015-01-01T23:59:59.000Z

298

Gravitation and Duality Symmetry  

E-Print Network [OSTI]

By generalizing the Hodge dual operator to the case of soldered bundles, and working in the context of the teleparallel equivalent of general relativity, an analysis of the duality symmetry in gravitation is performed. Although the basic conclusion is that, at least in the general case, gravitation is not dual symmetric, there is a particular theory in which this symmetry shows up. It is a self dual (or anti-self dual) teleparallel gravity in which, due to the fact that it does not contribute to the interaction of fermions with gravitation, the purely tensor part of torsion is assumed to vanish. The ensuing fermionic gravitational interaction is found to be chiral. Since duality is intimately related to renormalizability, this theory may eventually be more amenable to renormalization than teleparallel gravity or general relativity.

V. C. de Andrade; A. L. Barbosa; J. G. Pereira

2005-05-16T23:59:59.000Z

299

Investigation into environmentally friendly alternative cleaning processes for hybrid microcircuits to replace vapor degreasing with 1,1,1-trichloroethane. Final report  

SciTech Connect (OSTI)

Two cleaning processes, one aqueous and one nonaqueous, were investigated as potential replacements for the vapor degreasing process using 1,1,1 trichloroethane (TCA) for hybrid microcircuit assemblies. The aqueous process was based upon saponification chemistry. A 10% solution of either Kester 5768 or Armakleen 2001, heated to 140 F, was sprayed on the hybrid at 450 psig and a flow rate of 5 gpm through a specially designed nozzle which created microdroplets. The nonaqueous process was based upon dissolution chemistry and used d-limonene as the solvent in an immersion and spray process. The d-limonene solvent was followed by an isopropyl alcohol spray rinse to remove the excess d-limonene. The aqueous microdroplet process was found to be successful only for solder reflow profiles that did not exceed 210 C. Furthermore, removal of component marking was a problem and the spray pressure had to be reduced to 130 psig to eliminate damage to capacitor end caps. The d-limonene cleaning was found to be successful for solder reflow temperature up to 250 C when using a four-step cleaning process. The four steps included refluxing the hybrid at 80 C, followed by soaking the hybrid in d-limonene which is heated to 80 C, followed by spray cleaning at 80 psig with room temperature d-limonene, followed by spray cleaning at 80 psig with room temperature IPA was developed to remove residual flux from the hybrid microcircuits. This process was the most robust and most closely matched the cleaning ability of TCA.

Adams, B.E.

1997-02-01T23:59:59.000Z

300

Materials Compatibility and Aging for Flux and Cleaner Combinations.  

SciTech Connect (OSTI)

A materials study of high reliability electronics cleaning is presented here. In Phase 1, mixed type substrates underwent a condensed contaminants application to view a worst- case scenario for unremoved flux with cleaning agent residue for parts in a silicone oil filled environment. In Phase 2, fluxes applied to copper coupons and to printed wiring boards underwent gentle cleaning then accelerated aging in air at 65% humidity and 30 O C. Both sets were aged for 4 weeks. Contaminants were no-clean (ORL0), water soluble (ORH1 liquid and ORH0 paste), and rosin (RMA; ROL0) fluxes. Defluxing agents were water, solvents, and engineered aqueous defluxers. In the first phase, coupons had flux applied and heated, then were placed in vials of oil with a small amount of cleaning agent and additional coupons. In the second phase, pairs of copper coupons and PWB were hand soldered by application of each flux, using tin-lead solder in a strip across the coupon or a set of test components on the PWB. One of each pair was cleaned in each cleaning agent, the first with a typical clean, and the second with a brief clean. Ionic contamination residue was measured before accelerated aging. After aging, substrates were removed and a visual record of coupon damage made, from which a subjective rank was applied for comparison between the various flux and defluxer combinations; more corrosion equated to higher rank. The ORH1 water soluble flux resulted in the highest ranking in both phases, the RMA flux the least. For the first phase, in which flux and defluxer remained on coupons, the aqueous defluxers led to worse corrosion. The vapor phase cleaning agents resulted in the highest ranking in the second phase, in which there was no physical cleaning. Further study of cleaning and rinsing parameters will be required.

Archuleta, Kim; Piatt, Rochelle

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Quantum coherent transport in SnTe topological crystalline insulator thin films  

SciTech Connect (OSTI)

Topological crystalline insulators (TCI) are unique systems where a band inversion that is protected by crystalline mirror symmetry leads to a multiplicity of topological surface states. Binary SnTe is an attractive lead-free TCI compound; the present work on high-quality thin films provides a route for increasing the mobility and reducing the carrier density of SnTe without chemical doping. Results of quantum coherent magnetotransport measurements reveal a multiplicity of Dirac surface states that are unique to TCI. Modeling of the weak antilocalization shows variations in the extracted number of carrier valleys that reflect the role of coherent intervalley scattering in coupling different Dirac states on the degenerate TCI surface.

Assaf, B. A.; Heiman, D. [Department of Physics, Northeastern University, Boston, Massachusetts 02115 (United States); Katmis, F.; Moodera, J. S. [Francis Bitter Magnet Laboratory, MIT, Cambridge, Massachusetts 02139 (United States); Department of Physics, MIT, Cambridge, Massachusetts 02139 (United States); Wei, P. [Department of Physics, MIT, Cambridge, Massachusetts 02139 (United States); Satpati, B. [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Zhang, Z. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bennett, S. P.; Harris, V. G. [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States)

2014-09-08T23:59:59.000Z

302

The electronic properties and lattice dynamics of (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3}: From cubic to tetragonal and rhombohedral phases  

SciTech Connect (OSTI)

The structural, electronic and dynamical properties of the cubic, tetragonal and rhombohedral phases of a lead-free ferroelectrics, (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} (NBT), have been studied with a density functional formalism. The direct band gap is determined to be 2?3?eV for three phases, suggesting them to be good optical material. The equilibrium structures were given, and the importance of Bi atom in the low-symmetry ferroelectric phases were investigated with the electron localization functions analysis. The vibration modes at the ? point were calculated to provide a basis for analyzing the Raman and IR spectra. Soft modes were found in both the cubic and the tetragonal phases, providing a clue in understanding the ferroelectric phase transition in NBT.

Lü, Hongfeng [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Wang, Shanying [Department of Physics, Tsinghua University, Beijing 100084 (China); Wang, Xiaosu, E-mail: xiaosuwang@cau.edu.cn [Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China); Department of Physics, Tsinghua University, Beijing 100084 (China)

2014-03-28T23:59:59.000Z

303

Aging in the relaxor and ferroelectric state of Fe-doped (1-x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} piezoelectric ceramics  

SciTech Connect (OSTI)

Aging of piezoelectric properties was investigated in lead-free (1???x)(Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-xBaTiO{sub 3} doped with 1at.?% Fe. The relaxor character of the un-poled material prevents macroscopic aging effects, while in the field-induced ferroelectric phase aging phenomena are similar to those found in lead zirconate titanate or barium titanate. Most prominent aging effects are the development of an internal bias field and the decrease of switchable polarization. These effects are temperature activated, and can be explained in the framework of defect complex reorientation. This picture is further supported by electron paramagnetic resonance spectra indicating the existence of (Fe{sub Ti}{sup ?}?V{sub O}{sup ••}){sup •} defect complexes in the Fe-doped material.

Sapper, Eva; Dittmer, Robert; Rödel, Jürgen [Materials Science Department, Technische Universität Darmstadt, 64287 Darmstadt (Germany); Damjanovic, Dragan [Ceramics Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne 1015 (Switzerland); Erdem, Emre [Institute of Physical Chemistry I, Universität Freiburg, 79104 Freiburg (Germany); Keeble, David J. [Division of Electronic Engineering and Physics, University of Dundee, Dundee DD1 4HN (United Kingdom); Jo, Wook [School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Granzow, Torsten [Centre de Recherche Public—Gabriel Lippmann, L-4422 Belvaux (Luxembourg)

2014-09-14T23:59:59.000Z

304

Dielectric, ferromagnetic and maganetoelectric properties of BaTiO{sub 3}–Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} composite ceramics  

SciTech Connect (OSTI)

Graphical abstract: - Highlights: • The lead-free ME ceramic composites BaTiO{sub 3}–Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} were successfully synthesized. • The composites showed high dielectric constant and low dielectric loss. • The composite with 30% NiZn ferrite presented good soft magnetic properties and ME performance. - Abstract: Lead-free magnetoelectric composite ceramics (1 ? x)BaTiO{sub 3}–xNi{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} (x = 0.15, 0.3, 0.45) were successfully prepared by conventional oxide ceramic process. The tetragonal perovskite BaTiO{sub 3} and cubic spinel Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} were confirmed by X-ray diffraction. The dielectric behaviors of all composite samples show a normal response to the increasing measurement frequency and Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} ferrite content. Well defined ferromagnetic hysteresis loops and obvious magnetoelectric coupling effect are observed in the composite ceramics. The influence of applied dc bias magnetic field and Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} ferrite content on the magnetoelectric coupling responding voltage is investigated. The strongest peak magnetoelectric coupling voltage coefficient is 124 ?V/cm Oe when x = 0.3, which corresponds to the maximum magnetoelectric coupling responding voltage of 200 ?V.

Zhang, Rong-Fen [Department of Electronic Science, College of Science, Key Laboratory of Functional Composite Materials of Guizhou Province, Guizhou University, Guiyang, Guizhou 550025 (China); Deng, Chao-Yong, E-mail: cydeng@gzu.edu.cn [Department of Electronic Science, College of Science, Key Laboratory of Functional Composite Materials of Guizhou Province, Guizhou University, Guiyang, Guizhou 550025 (China); Ren, Li [Department of Electronic Science, College of Science, Key Laboratory of Functional Composite Materials of Guizhou Province, Guizhou University, Guiyang, Guizhou 550025 (China); Li, Zheng [Department of Materials Science and Engineering, State Key Laboratory of New Ceramics and Fine Processing, Tsinghua University, Beijing 100084 (China); Zhou, Jian-Ping [College of Physics and Information Technology, Shaanxi Normal University, Xi’an 710062 (China)

2013-10-15T23:59:59.000Z

305

Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts  

SciTech Connect (OSTI)

The goal of this project was to study the combined effects of die design, proper internal cooling and efficient die lubricants on die life. The project targeted improvements in die casting insert life by: Optomized Die Design for Reduced Surface Temperature: The life of die casting dies is significantly shorter when the die is exposed to elevated temperature for significant periods of time. Any die operated under conditions leading to surface temperature in excess of 1050oF undergoes structural changes that reduce its strength. Optimized die design can improve die life significantly. This improvement can be accomplished by means of cooling lines, baffles and bubblers in the die. A key objective of the project was to establish criteria for the minimal distance of the cooling lines from the surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. The Uddeholm Dievar steel evaluated in this program showed superior resistance to thermal fatigue resistance. Based on the experimental evidence, cooling lines could be placed as close as 0.5"Ā¯ from the surface. Die Life Extension by Optimized Die Lubrication: The life of die casting dies is affected by additions made to its surface with the proper lubricants. These lubricants will protect the surface from the considerable temperature peaks that occur when the molten melt enters the die. Dies will reach a significantly higher temperature without this lubricant being applied. The amount and type of the lubricant are critical variables in the die casting process. However, these lubricants must not corrode the die surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. Chem- Trend participated in the program with die lubricants and technical support. Experiments conducted with these lubricants demonstrated good protection of the substrate steel. Graphite and boron nitride used as benchmarks are capable of completely eliminating soldering and washout. However, because of cost and environmental considerations these materials are not widely used in industry. The best water-based die lubricants evaluated in this program were capable of providing similar protection from soldering and washout. In addition to improved part quality and higher production rates, improving die casting processes to preserve the life of the inserts will result in energy savings and a reduction in environmental wastes. Improving die life by means of optimized cooling line placement, baffles and bubblers in the die will allow for reduced die temperatures during processing, saving energy associated with production. The utilization of optimized die lubricants will also reduce heat requirements in addition to reducing waste associated with soldering and washout. This new technology was predicted to result in an average energy savings of 1.1 trillion BTU's/year over a 10 year period. Current (2012) annual energy saving estimates, based on commercial introduction in 2010, a market penetration of 70% by 2020 is 1.26 trillion BTU's/year. Along with these energy savings, reduction of scrap and improvement in casting yield will result in a reduction of the environmental emissions associated with the melting and pouring of the metal which will be saved as a result of this technology. The average annual estimate of CO2 reduction per year through 2020 is 0.025 Million Metric Tons of Carbon Equivalent (MM TCE).

David Schwam, PI; Xuejun Zhu, Sr. Research Associate

2012-09-30T23:59:59.000Z

306

The Calculated and Measured Resistance for Splices between Conductors in a MICE Superconducting Coil  

SciTech Connect (OSTI)

The resistance of superconducting joints within MICE coils is an important issue particularly for the coupling coils. The MICE tracker solenoids have only two superconducting joints in the three spectrometer set (end coil 1, the center coil and end coil 2). The AFC magnets may have only a single joint within the coil. The coupling coils may have as many as fifteen joints within the coil, due to relatively short piece lengths of the superconductor. LBNL and ICST looked at three types of coil joints. They are: (1) cold fusion butt joints, (2) side-by-side lap joints, and (3) up-down lap joints. A theoretical calculation of the joint resistance was done at LBNL and checked by ICST. After looking at the theoretical resistance of the three types of joints, it was decided that the cold welded butt joint was not an attractive alternative for joints within a MICE superconducting magnet coil. Side-by-side and up-down lap joints were fabricated at ICST using two types of soft solder between the conductors. These conductor joints were tested at LBNL at liquid helium temperatures over a range of magnetic fields. The joint resistance was compared with the theoretical calculations. Measurements of splice strength were also made at 300 K and 77 K.

Green, Michael A.; Dietderich, Dan; Higley, Hugh; Pan, Heng; Tam, Darren; Trillaud, Federic; Wang, Li; Wu, Hong; Xu, Feng Yu

2009-03-19T23:59:59.000Z

307

Engine coolant technology, performance, and life for light-duty applications  

SciTech Connect (OSTI)

Recently there has been interest by motor vehicle manufacturers in developing longer-lived automotive engine coolants with an emphasis on organic acid technology (OAT). Paradoxically, the lifetime of conventional technology remains largely undefined. Concerns arising from the depleting nature of silicate have led to modern conservative change recommendations of 30,000 to 50,000 miles ({approximately}48,279 to 80,464 km). In the present work, laboratory bench test, engine dynamometer and vehicle service data from traditional silicate, hybrid and nonsilicate coolants are compared and contrasted. A new electrochemical test is used to examine passivation kinetics on aluminum. It is shown that performance and lifetime are independent of chemistry and cannot be generalized. Examples include an American silicate coolant with excellent performance on high-heat-rejecting aluminum (80 W/cm{sup 2}). European and American silicate coolants with performance defined lifetimes in excess of 300,000 miles (482,790 km), and an OAT coolant with laboratory high lead solder protection. It is concluded that the primary benefit of OAT is to meet global specifications that include chemical limitations.

Turcotte, D.E.; Lockwood, F.E. [Valvoline Co., Lexington, KY (United States); Pfitzner, K.K.; Meszaros, L.L. [BASF Aktiengesellschaft, Ludwigshafen (Germany); Listebarger, J.K. [Ashland Chemical, Dublin, OH (United States)

1999-08-01T23:59:59.000Z

308

Photovoltaic concentrator module improvements study  

SciTech Connect (OSTI)

This report presents results of a project to design and fabricate an improved photovoltaic concentrator module. Using previous work as a baseline, this study conducted analyses and testing to select major module components and design features. The lens parquet and concentrator solar cell were selected from the highest performing, available components. A single 185X point-focus module was fabricated by the project team and tested at Sandia. Major module characteristics include a 6 by 4 compression-molded acrylic lens parquet (0.737 m{sup 2} area), twenty-four 0.2 ohms-cm, FZ, p-Si solar cells (1.56 cm{sup 2} area) soldered to ceramic substrates and copper heat spreaders, and an aluminized steel housing with corrugated bottom. This project marked the first attempt to use prismatic covers on solar cells in a high-concentration, point-focus application. Cells with 15 percent metallization were obtained, but problems with the fabrication and placement of prismatic covers on these cells lead to the decision not to use covers in the prototype module. Cell assembly fabrication, module fabrication, and module optical design activities are presented here. Test results are also presented for bare cells, cell assemblies, and module. At operating conditions of 981 watts/m{sup 2} DNI and an estimated cell temperature of 65{degrees}C, the module demonstrated an efficiency of 13.9 percent prior to stressed environmental exposure. 12 refs., 56 figs., 7 tabs.

Levy, S.L.; Kerschen, K.A. (Black and Veatch, Kansas City, MO (United States)); Hutchison, G. (Solar Kinetics, Inc., Dallas, TX (United States)); Nowlan, M.J. (Spire Corp., Bedford, MA (United States))

1991-08-01T23:59:59.000Z

309

Explosion bonding of dissimilar materials for fabricating APS front end components: Analysis of metallurgical and mechanical properties and UHV applications  

SciTech Connect (OSTI)

The front end beamline section contains photon shutters and fixed masks. These components are made of OFHC copper and GlidCOP AL-15. Stainless steels (304 or 316) are also used for connecting photon shutters and fixed masks to other components that operate in the ultrahigh vacuum system. All these dissimilar materials need to be joined together. However, bonding these dissimilar materials is very difficult because of their different mechanical and thermal properties and incompatible metallurgical properties. Explosion bonding is a bonding method in which the controlled energy of a detonating explosive is used to create a metallurgical bond between two or more similar or dissimilar materials. No intermediate filler metal, for example, a brazing compound or soldering alloy, is needed to promote bonding, and no external heat need be applied. A study of the metallurgical and mechanical properties and YGV applications of GlidCop AL-15, OFHC copper, and 304 stainless steel explosion-bonded joints has been done. This report contains five parts: an ultrasonic examination of explosion-bonded joints and a standard setup; mechanical-property and thermal-cycle tests of GlidCop AL-15/304 stainless steel explosion-bonded joints; leak tests of a GlidCop AL-15/304 stainless steel explosion-bonded interfaces for UHV application; metallurgical examination of explosion-bonded interfaces and failure analysis, and discussion and conclusion.

Li, Yuheng; Shu, Deming; Kuzay, T.M.

1994-06-15T23:59:59.000Z

310

Low thermal resistance power module assembly  

DOE Patents [OSTI]

A power module assembly (400) with low thermal resistance and enhanced heat dissipation to a cooling medium. The assembly includes a heat sink or spreader plate (410) with passageways or openings (414) for coolant that extend through the plate from a lower surface (411) to an upper surface (412). A circuit substrate (420) is provided and positioned on the spreader plate (410) to cover the coolant passageways. The circuit substrate (420) includes a bonding layer (422) configured to extend about the periphery of each of the coolant passageways and is made up of a substantially nonporous material. The bonding layer (422) may be solder material which bonds to the upper surface (412) of the plate to provide a continuous seal around the upper edge of each opening (414) in the plate. The assembly includes power modules (430) mounted on the circuit substrate (420) on a surface opposite the bonding layer (422). The power modules (430) are positioned over or proximal to the coolant passageways.

Hassani, Vahab (Denver, CO); Vlahinos, Andreas (Castle Rock, CO); Bharathan, Desikan (Arvada, CO)

2010-12-28T23:59:59.000Z

311

Condensed Geometry  

E-Print Network [OSTI]

A spin (dependent) system treatment of gravity is adopted akin to the Sen-Ashtekar treatment. Time is reinserted into the space ``fluid'' at the quantum Level. This time - the Lorentzian one- is shown to be a vorticity of a ``fluid particle'' of the space and the effect is integrated over all the fluid particles to incorporate time in quantum gravity. This spacetime is viewed as a fluid of future light cones called the SU(2) dipoles of causality here in the paper.The future light cone structure is soldered internally to the new variables derived in this paper to accomodate a background free physics of quantum strings. The emergence of spacetime is shown to be a first order phase transition and that of separation of gravity from the unified field to be a second order phase transition. For the former case the cosmic time is chosen as the order parameter and for the latter case the angular momentum is chosen as the order parameter. A quantum blackhole thus nucleates at transition temperature which is the Planck temperature, $\\tau_{pl}$. Then the SU(2) dipoles enable interpretation of this black hole as a gravity gauge SL(2,$\\mathbb{C}$) dual of the U(1) gauge ferromagnetic phase. The usual QFT interpretation of this effect is the existence of locally Lorentzian spacetimes.

Koustubh Kabe

2010-02-10T23:59:59.000Z

312

Apparatus And Method Of Using Flexible Printed Circuit Board In Optical Transceiver Device  

DOE Patents [OSTI]

This invention relates to a flexible printed circuit board that is used in connection with an optical transmitter, receiver or transceiver module. In one embodiment, the flexible printed circuit board has flexible metal layers in between flexible insulating layers, and the circuit board comprises: (1) a main body region orientated in a first direction having at least one electrical or optoelectronic device; (2) a plurality of electrical contact pads integrated into the main body region, where the electrical contact pads function to connect the flexible printed circuit board to an external environment; (3) a buckle region extending from one end of the main body region; and (4) a head region extending from one end of the buckle region, and where the head region is orientated so that it is at an angle relative to the direction of the main body region. The electrical contact pads may be ball grid arrays, solder balls or land-grid arrays, and they function to connect the circuit board to an external environment. A driver or amplifier chip may be adapted to the head region of the flexible printed circuit board. In another embodiment, a heat spreader passes along a surface of the head region of the flexible printed circuit board, and a window is formed in the head region of the flexible printed circuit board. Optoelectronic devices are adapted to the head spreader in such a manner that they are accessible through the window in the flexible printed circuit board.

Anderson, Gene R. (Albuquerque, NM); Armendariz, Marcelino G. (Albuquerque, NM); Bryan, Robert P. (Albuquerque, NM); Carson, Richard F. (Albuquerque, NM); Duckett, III, Edwin B. (Albuquerque, NM); McCormick, Frederick B. (Albuquerque, NM); Peterson, David W. (Sandia Park, NM); Peterson, Gary D. (Albuquerque, NM); Reysen, Bill H. (Lafayette, CO)

2005-03-15T23:59:59.000Z

313

Investigation of proposed process sequence for the array automated assembly task. Phase I and II. Final report, October 1, 1977-June 30, 1980  

SciTech Connect (OSTI)

A selected process sequence for the low cost fabrication of photovoltaic modules was defined during this contract. Each part of the process sequence was looked at regarding its contribution to the overall dollars per watt cost. During the course of the research done, some of the initially included processes were dropped due to technological deficiencies. The printed dielectric diffusion mask, codiffusion of the n+ and p+ regions, wraparound front contacts and retention of the diffusion oxide for use as an AR coating were all the processes that were removed for this reason. Other process steps were retained to achieve the desired overall cost and efficiency. Square wafers, a polymeric spin-on PX-10 diffusion source, a p+ back surface field and silver front contacts are all processes that have been recommended for use in this program. The printed silver solderable pad for making contact to the aluminum back was replaced by an ultrasonically applied tin-zinc pad. Also, the texturized front surface was dropped as inappropriate for the sheet silicon likely to be available in 1986. Progress has also been made on the process sequence for module fabrication. A shift from bonding with a conformal coating to laminating with ethylene vinyl acetate and a glass superstrate is recommended for further module fabrication. The finalized process sequence is described.

Mardesich, N.; Garcia, A.; Eskenas, K.

1980-08-01T23:59:59.000Z

314

Liquid immiscibility and core-shell morphology formation in ternary Al–Bi–Sn alloys  

SciTech Connect (OSTI)

The effects of composition on liquid immiscibility, macroscopic morphology, microstructure and phase transformation in ternary Al–Bi–Sn alloys were investigated. Three types of morphology, the core-shell type, the stochastic droplet type and uniform dispersion type, of Al–Bi–Sn particles prepared by a jet breakup process were distinguished, and the relationships between which were discussed. The phase transformation behaviors of the Al–Bi–Sn alloys were studied by thermal analysis, in agreement with the microstructural observation and microanalysis. The liquid immiscibility and formation of the core-shell morphology in Al–Bi–Sn alloys are easily achieved when the composition lies in the liquid miscibility gap. The particles exhibit a high melting point Al-rich core with a low melting point Sn–Bi-rich solder shell, showing promise for application as high-density electronic packaging materials. - Highlights: • The liquid demixing, morphology and microstructure in Al–Bi–Sn alloys were studied. • Three types of morphology were classified and discussed. • The conditions for formation of the core-shell morphology were obtained. • The phase transition behaviors agree with the microstructure characterization. • The Al/Sn–Bi core-shell particles show promise for use in electronic packaging.

Dai, R.; Zhang, J.F.; Zhang, S.G., E-mail: sgzhang@sjtu.edu.cn; Li, J.G.

2013-07-15T23:59:59.000Z

315

Laser-induced breakdown spectroscopy in industrial and security applications  

SciTech Connect (OSTI)

Laser-induced breakdown spectroscopy (LIBS) offers rapid, localized chemical analysis of solid or liquid materials with high spatial resolution in lateral and depth profiling, without the need for sample preparation. Principal component analysis and partial least squares algorithms were applied to identify a variety of complex organic and inorganic samples. This work illustrates how LIBS analyzers can answer a multitude of real-world needs for rapid analysis, such as determination of lead in paint and children's toys, analysis of electronic and solder materials, quality control of fiberglass panels, discrimination of coffee beans from different vendors, and identification of generic versus brand-name drugs. Lateral and depth profiling was performed on children's toys and paint layers. Traditional one-element calibration or multivariate chemometric procedures were applied for elemental quantification, from single laser shot determination of metal traces at {approx}10 {mu}g/g to determination of halogens at 90 {mu}g/g using 50-shot spectral accumulation. The effectiveness of LIBS for security applications was demonstrated in the field by testing the 50-m standoff LIBS rasterizing detector.

Bol'shakov, Alexander A.; Yoo, Jong H.; Liu Chunyi; Plumer, John R.; Russo, Richard E.

2010-05-01T23:59:59.000Z

316

A novel planar ion funnel design for miniature ion optics  

SciTech Connect (OSTI)

The novel planar ion funnel (PIF) design presented in this article emphasizes simple fabrication, assembly, and operation, making it amenable to extreme miniaturization. Simulations performed in SIMION 8.0 indicate that ion focusing can be achieved by using a gradient of electrostatic potentials on concentric metal rings in a plane. A prototype was fabricated on a 35 × 35 mm custom-designed printed circuit board (PCB) with a center hole for ions to pass through and a series of concentric circular metal rings of increasing diameter on the front side of the PCB. Metal vias on the PCB electrically connected each metal ring to a resistive potential divider that was soldered on the back of the PCB. The PIF was tested at 5.5 × 10{sup ?6} Torr in a vacuum test setup that was equipped with a broad-beam ion source on the front and a micro channel plate (MCP) ion detector on the back of the PIF. The ion current recorded on the MCP anode during testing indicated a 23× increase in the ion transmission through the PIF when electric potentials were applied to the rings. These preliminary results demonstrate the functionality of a 2D ion funnel design with a much smaller footprint and simpler driving electronics than conventional 3D ion funnels. Future directions to improve the design and a possible micromachining approach to fabrication are discussed in the conclusions.

Chaudhary, A.; Amerom, Friso H. W. van; Short, R. T. [Space and Marine Technology Laboratory, SRI International, 450 8th Ave SE, St. Petersburg, Florida 33701 (United States)

2014-10-15T23:59:59.000Z

317

Liquid cooled, linear focus solar cell receiver  

DOE Patents [OSTI]

Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

Kirpich, Aaron S. (Broomall, PA)

1985-01-01T23:59:59.000Z

318

Review of Back Contact Silicon Solar Cells for Low-Cost Application  

SciTech Connect (OSTI)

Back contact solar cells hold significant promise for increased performance in photovoltaics for the near future. Two major advantages which these cells possess are a lack of grid shading loss and coplanar interconnection. Front contacted cells can have up to 10% shading loss when using screen printed metal grids. A front contact cell must also use solder connections which run from the front of one cell to the back of the next for series interconnection. This procedure is more difficult to automate than the case of co-planar contacts. The back contact cell design is not a recent concept. The earliest silicon solar cell developed by Bell Labs was a back contact device. There have been many design modifications to the basic concept over the years. To name a few, there is the Interdigitated Back Contact (IBC) cell, the Stanford Point contact solar cell, the Emitter Wrap Through (EWT), and its many variations. A number of these design concepts have demonstrated high efficiency. The SunPower back contact solar cell holds the efficiency record for silicon concentrator cells. The challenge is to produce a high efficiency cell at low cost using high throughput techniques. This has yet to be achieved with a back contact cell design. The focus of this paper will be to review the relevant features of back contact cells and progress made toward the goal of a low cost version of this device.

Smith, David D.

1999-08-04T23:59:59.000Z

319

Liquid cooled, linear focus solar cell receiver  

DOE Patents [OSTI]

Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

Kirpich, A.S.

1983-12-08T23:59:59.000Z

320

Innovative Seals for Solid Oxide Fuel Cells (SOFC)  

SciTech Connect (OSTI)

A functioning SOFC requires different type of seals such as metal-metal, metal-ceramic, and ceramic-ceramic. These seals must function at high temperatures between 600--900{sup o}C and in oxidizing and reducing environments of the fuels and air. Among the different type of seals, the metal-metal seals can be readily fabricated using metal joining, soldering, and brazing techniques. However, the metal-ceramic and ceramic-ceramic seals require significant research and development because the brittle nature of ceramics/glasses can lead to fracture and loss of seal integrity and functionality. Consequently, any seals involving ceramics/glasses require a significant attention and technology development for reliable SOFC operation. This final report is prepared to describe the progress made in the program on the needs, approaches, and performance of high temperature seals for SOFC. In particular, a new concept of self-healing glass seals is pursued for making seals between metal-ceramic material combinations, including some with a significant expansion mismatch.

Singh, Raj

2008-06-30T23:59:59.000Z

Note: This page contains sample records for the topic "lead-free solder misbehaves" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Microchannel heat sink assembly  

DOE Patents [OSTI]

The present invention provides a microchannel heat sink with a thermal range from cryogenic temperatures to several hundred degrees centigrade. The heat sink can be used with a variety of fluids, such as cryogenic or corrosive fluids, and can be operated at a high pressure. The heat sink comprises a microchannel layer preferably formed of silicon, and a manifold layer preferably formed of glass. The manifold layer comprises an inlet groove and outlet groove which define an inlet manifold and an outlet manifold. The inlet manifold delivers coolant to the inlet section of the microchannels, and the outlet manifold receives coolant from the outlet section of the microchannels. In one embodiment, the manifold layer comprises an inlet hole extending through the manifold layer to the inlet manifold, and an outlet hole extending through the manifold layer to the outlet manifold. Coolant is supplied to the heat sink through a conduit assembly connected to the heat sink. A resilient seal, such as a gasket or an O-ring, is disposed between the conduit and the hole in the heat sink in order to provide a watertight seal. In other embodiments, the conduit assembly may comprise a metal tube which is connected to the heat sink by a soft solder. In still other embodiments, the heat sink may comprise inlet and outlet nipples. The present invention has application in supercomputers, integrated circuits and other electronic devices, and is suitable for cooling materials to superconducting temperatures. 13 figs.

Bonde, W.L.; Contolini, R.J.

1992-03-24T23:59:59.000Z

322

High field Nb/sub 3/Sn Axicell insert coils for the Mirror Fusion Test Facility-B (MFTF-B) axicell configuration. Final report  

SciTech Connect (OSTI)

Two 12-tesla superconducting insert coils are being designed by General Dynamics Convair Division for the axicell regions of MFTF-B for Lawrence Livermore National Laboratory. A major challenge of this project is to ensure that combined fabrication and operational strains induced in the conductor are within stringent limitations of the relatively brittle Nb/sub 3/Sn superconductor filaments. These coils are located in the axicell region of MFTF-B. They have a clear-bore diameter of 36.195cm (14.25 inches) and consist of 27 double pancakes (i.e., 54 pancakes per coil) would on an electrically insulated 304LN stainless steel/bobbin helium vessel. Each pancake has 57 turns separated by G-10CR insulation. The complete winding bundle has 4.6 million ampere-turns and uniform current density of 2007 A/cm/sup 2/. In conjunction with the other magnets in the system, they produce a 12-tesla central field and a 12.52-tesla peak field. A multifilamentary Nb/sub 3/Sn conductor was selected to meet these requirements. The conductor consists of a monolithic insert soldered into a copper stabilizer. Sufficient cross-sectional area and work-hardening of the copper stabilizer has been provided for the conductor to self-react the electromagnetic Lorentz force induced hoop stresses with normal operational tensile strains less than 0.07 percent.

Baldi, R.W.; Tatro, R.E.; Scanlan, R.M.; Agarwal, K.L.; Bailey, R.E.; Burgeson, J.E.; Kim, I.K.; Magnuson, G.D.; Mallett, B.D.; Pickering, J.L.

1984-03-01T23:59:59.000Z

323

Robust hermetic packaging techniques for MEMS integrated microsystems.  

SciTech Connect (OSTI)

This work is the result of a Sandia National Laboratories LDRD funded fellowship at the University of Michigan. Although, guidance and suggestions were offered by Sandia, the work contained here is primarily the work of Brian H. Stark, and his advisor, Professor Khalil Najafi. Junseok Chae, Andrew Kuo, and their coworkers at the University of Michigan helped to record some of the data. The following is an abstract of their work. We have developed a vacuum packaging technology using a thick nickel film to seal MEMS structures at the wafer level. The package is fabricated in a three-mask process by electroplating a 40 micro-meter thick nickel film over an 8 micro-meter sacrificial photoresist that is removed prior to package sealing. Implementation of electrical feedthroughs in this process requires no planarization. The large release channel enables an 800x800 micro-meter package to be released in less than three hours. Several mechanisms, based upon localized melting and lead/tin solder bumping, for sealing the release channel have been investigated. We have also developed Pirani gauges, integrated with this package, which can be used to establish the hermeticity of the different sealing technologies. They have measured a sealing pressure of approximately 1.5 Torr. Our work differs from previous Pirani gauges in that we utilize a novel doubly anchored structure that stiffens the structural membrane while not substantially degrading performance in order to measure fine leak rates.

Chae, Junseok (University of Michigan); Stark, Brian H. (University of Michigan); Kuo, Andrew (University of Michigan); Oliver, Andrew David; Najafi, Khalil (University of Michigan)

2005-03-01T23:59:59.000Z

324

Low cost impulse compatible wideband antenna  

DOE Patents [OSTI]

An antenna apparatus and method for building the antenna is disclosed. Impulse signals travel through a feed point of the antenna with respect to a ground plane. A geometric fin structure is connected to the feed point, and through a termination resistance to the ground plane. A geometric ridge structure connected to the ground is positioned with respect to the fin in order to receive and radiate electromagnetic energy from the impulse signal at a predetermined impedance and over a predetermined set of frequencies. The fin and ridge can be either a wire or a planar surface. The fin and ridge may be disposed within a radiation cavity such as a horn. The radiation cavity is constructed of stamped and etched metal sheets bent and then soldered together. The fin and ridge are also formed from metal sheets or wires. The fin is attached to the feed point and then to the cavity through a termination resistance. The ridge is attached to the cavity and disposed with respect to the fin in order to achieve a particular set of antenna characteristics.

Rosenbury, Erwin T. (Livermore, CA); Burke, Gerald J. (Livermore, CA); Nelson, Scott D. (Tracy, CA); Stever, Robert D. (Lathrop, CA); Governo, George K. (Livermore, CA); Mullenhoff, Donald J. (Livermore, CA)

2002-01-01T23:59:59.000Z

325

Investigation on transition behavior and electrical properties of (K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} around polymorphic phase transition region  

SciTech Connect (OSTI)

(K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} (KNLNTS) lead free ceramics with different Li concentration were fabricated by conventional solid-state reaction method. By increasing Li ions in KNLNTS, the grains grow up and the crystal structure changes from orthorhombic to tetragonal. When 0.03 ? x ? 0.05, the ceramics structure lays in PPT region. Polarization versus electric field (P-E) hysteresis loops at room temperature show good ferroelectric properties and the remnant polarization decreases by increasing Li content while coercive electric keeps almost unchanged. In PPT region, taking x = 0.04 as an example, the sample shows excellent dielectric properties: the dielectric constant is 1159 and loss tangent is 0.04, while the piezoelectric constant d{sub 33} is 245 pC/N and kp is 0.44 at room temperature, it is promising for (K{sub 0.5}Na{sub 0.5}){sub 1-x}Li{sub x}Nb{sub 0.84}Ta{sub 0.1}Sb{sub 0.06}O{sub 3} with 4 at. % Li to substitute PZT.

Zhu, Chen; Wang, Wenchao; Shi, Honglin; Wang, Fangyu; Cao, Yongge [Department of Physics, Renmin University of China, Beijing 100872, P R China (China) [Department of Physics, Renmin University of China, Beijing 100872, P R China (China); Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Huang, Jiquan; Wang, Chong [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)] [Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Tang, Fei; Yuan, Xuanyi, E-mail: yuanxuanyi@ruc.edu.cn [Department of Physics, Renmin University of China, Beijing 100872, P R China (China)] [Department of Physics, Renmin University of China, Beijing 100872, P R China (China); Liu, Yang [School of Chemistry and Environment Engineering, Shaoguan University, Shaoguan 512005 (China)] [School of Chemistry and Environment Engineering, Shaoguan University, Shaoguan 512005 (China)

2014-01-15T23:59:59.000Z

326

Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Use of Laser Engineered Net Shaping for Rapid Manufacturing of Dies with Protective Coatings and Improved Thermal Management  

SciTech Connect (OSTI)

In the high pressure die casting process, molten metal is introduced into a die cavity at high pressure and velocity, enabling castings of thin wall section and complex geometry to be obtained. Traditional die materials have been hot work die steels, commonly H13. Manufacture of the dies involves machining the desired geometry from monolithic blocks of annealed tool steel, heat treating to desired hardness and toughness, and final machining, grinding and polishing. The die is fabricated with internal water cooling passages created by drilling. These materials and fabrication methods have been used for many years, however, there are limitations. Tool steels have relatively low thermal conductivity, and as a result, it takes time to remove the heat from the tool steel via the drilled internal water cooling passages. Furthermore, the low thermal conductivity generates large thermal gradients at the die cavity surfaces, which ultimately leads to thermal fatigue cracking on the surfaces of the die steel. The high die surface temperatures also promote the metallurgical bonding of the aluminum casting alloy to the surface of the die steel (soldering). In terms of process efficiency, these tooling limitations reduce the number of die castings that can be made per unit time by increasing cycle time required for cooling, and increasing downtime and cost to replace tooling which has failed either by soldering or by thermal fatigue cracking (heat checking). The objective of this research was to evaluate the feasibility of designing, fabricating, and testing high pressure die casting tooling having properties equivalent to H13 on the surface in contact with molten casting alloy - for high temperature and high velocity molten metal erosion resistance – but with the ability to conduct heat rapidly to interior water cooling passages. A layered bimetallic tool design was selected, and the design evaluated for thermal and mechanical performance via finite element analysis. H13 was retained as the exterior layer of the tooling, while commercially pure copper was chosen for the interior structure of the tooling. The tooling was fabricated by traditional machining of the copper substrate, and H13 powder was deposited on the copper via the Laser Engineered Net Shape (LENSTM) process. The H13 deposition layer was then final machined by traditional methods. Two tooling components were designed and fabricated; a thermal fatigue test specimen, and a core for a commercial aluminum high pressure die casting tool. The bimetallic thermal fatigue specimen demonstrated promising performance during testing, and the test results were used to improve the design and LENS TM deposition methods for subsequent manufacture of the commercial core. Results of the thermal finite element analysis for the thermal fatigue test specimen indicate that it has the ability to lose heat to the internal water cooling passages, and to external spray cooling, significantly faster than a monolithic H13 thermal fatigue sample. The commercial core is currently in the final stages of fabrication, and will be evaluated in an actual production environment at Shiloh Die casting. In this research, the feasibility of designing and fabricating copper/H13 bimetallic die casting tooling via LENS TM processing, for the purpose of improving die casting process efficiency, is demonstrated.

Brevick, Jerald R. [Ohio State University

2014-06-13T23:59:59.000Z

327

Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Surface Engineered Coating Systems for Aluminum Pressure Die Casting Dies: Towards a 'Smart' Die Coating  

SciTech Connect (OSTI)

The main objective of this research program was to design and develop an optimal coating system that extends die life by minimizing premature die failure. In high-pressure aluminum die-casting, the die, core pins and inserts must withstand severe processing conditions. Many of the dies and tools in the industry are being coated to improve wear-resistance and decrease down-time for maintenance. However, thermal fatigue in metal itself can still be a major problem, especially since it often leads to catastrophic failure (i.e. die breakage) as opposed to a wear-based failure (parts begin to go out of tolerance). Tooling costs remain the largest portion of production costs for many of these parts, so the ability prevent catastrophic failures would be transformative for the manufacturing industry.The technology offers energy savings through reduced energy use in the die casting process from several factors, including increased life of the tools and dies, reuse of the dies and die components, reduction/elimination of lubricants, and reduced machine down time, and reduction of Al solder sticking on the die. The use of the optimized die coating system will also reduce environmental wastes and scrap parts. Current (2012) annual energy saving estimates, based on initial dissemination to the casting industry in 2010 and market penetration of 80% by 2020, is 3.1 trillion BTU's/year. The average annual estimate of CO2 reduction per year through 2020 is 0.63 Million Metric Tons of Carbon Equivalent (MM TCE).

Dr. John J. Moore; Dr. Jianliang Lin,

2012-07-31T23:59:59.000Z

328

New adhesive systems based on functionalized block copolymers  

SciTech Connect (OSTI)

The goal of this work was to evaluate chemically-functionalized block copolymers as adhesion promoters for metal/thermoset resin interfaces. Novel block copolymers were synthesized which contain pendant functional groups reactive toward copper and epoxy resins. In particular, imidazole and triazole functionalities that chelate with copper were incorporated onto one block, while secondary amines were incorporated onto the second block. These copolymers were found to self-assemble from solution onto copper surfaces to form monolayers. The structure of the adsorbed monolayers were studied in detail by neutron reflection and time-of-flight secondary ion mass spectrometry. The monolayer structure was found to vary markedly with the solution conditions and adsorption protocol. Appropriate conditions were found for which the two blocks form separate layers on the surface with the amine functionalized block exposed at the air surface. Adhesion testing of block copolymer-coated copper with epoxy resins was performed in both lap shear and peel modes. Modest enhancements in bond strengths were observed with the block copolymer applied to the native oxide. However, it was discovered that the native oxide is the weak link, and that by simply removing the native oxide, and then applying an epoxy resin before the native oxide can reform, excellent bond strength in the as-prepared state as well as excellent retention of bond strength after exposure to solder in ambient conditions are obtained. It is recommended that long term aging studies be performed with and without the block copolymer. In addition, the functionalized block copolymer method should be evaluated for another system that has inherently poor bonding, such as the nickel/silicone interface, and for systems involving metals and alloys which form oxides very rapidly, such as aluminum and stainless steel, where bonding strategies involve stabilizing the native oxide.

Kent, M.; Saunders, R.; Hurst, M.; Small, J.; Emerson, J.; Zamora, D.

1997-05-01T23:59:59.000Z

329

GOMA - A full-Newton finite element program for free and moving boundary problems with coupled fluid/solid momentum, energy, mass, and chemical species transport: User`s guide  

SciTech Connect (OSTI)

GOMA is a two- and three-dimensional finite element program which excels in analyses of manufacturing processes, particularly those involving free or moving interfaces. Specifically, the full-Newton-coupled heat, mass, momentum, and pseudo-solid mesh motion algorithm makes GOMA ideally suited for simulating processes in which the bulk fluid transport is closely coupled to the interfacial physics. Examples include, but are not limited to, coating and polymer processing flows, soldering, crystal growth, and solid-network or solution film drying. The code is based on the premise that any boundary can be (1) moving or free, with an apriori unknown position dictated by the distinguishing physics, (2) fixed, according to a global analytical representation, or (3) moving in time and space under user-prescribed kinematics. The goal is to enable the user to predict boundary position or motion simultaneously with the physics of the problem being analyzed and to pursue geometrical design studies and fluid-structure interaction problems. The moving mesh algorithm treats the entire domain as a computational Lagrangian solid that deforms subject to the physical principles which dictate boundary position. As an added benefit, the same Lagrangian solid mechanics can be exploited to solve multi-field problems for which the solid motion and stresses interact with other transport phenomena, either within the same material phase (e.g. shrinking coating) or in neighboring material phases (e.g. flexible blade coating). Thus, analyses of many fluid-structure interaction problems and deformable porous media problems are accessible. This document serves as a user`s guide and reference for GOMA and provides a brief overview of GOMA`s capabilities, theoretical background, and classes of problems for which it is targeted.

Schunk, P.R.; Sackinger, P.A.; Rao, R.R. [and others] [and others

1996-01-01T23:59:59.000Z

330

Deactivation of the EBR-II complex  

SciTech Connect (OSTI)

In January of 1994, the Department of Energy mandated the termination of the Integral Fast Reactor (IFR) Program, effective October 1, 1994. To comply with this decision, Argonne National Laboratory-West (ANL-W) prepared a plan providing detailed requirements to place the Experimental Breeder Reactor-II (EBR-II) in a radiologically and industrially safe condition, including removal of all irradiated fuel assemblies from the reactor plant, and removal and stabilization of the primary and secondary sodium, a liquid metal used to transfer heat within the reactor plant. The ultimate goal of the deactivation process is to place the EBR-II complex in a stable condition until a decontamination and decommissioning (D&D) plan can be prepared, thereby minimizing requirements for maintenance and surveillance and maximizing the amount of time for radioactive decay. The final closure state will be achieved in full compliance with federal, state and local environmental, safety, and health regulations and requirements. The decision to delay the development of a detailed D&D plan has necessitated this current action. The EBR-II is a pool-type reactor. The primary system contains approximately 87,000 gallons of sodium, while the secondary system has 13,000 gallons. In order to properly dispose of the sodium in compliance with the Resource Conservation and Recovery Act (RCRA), a facility has been built to react the sodium to a dry carbonate powder in a two stage process. Deactivation of a liquid metal fast breeder reactor (LMFBR) presents unique concerns. Residual amounts of sodium remaining in the primary and secondary systems must be either reacted or inerted to preclude future concerns with sodium-air reactions that generate explosive mixtures of hydrogen and leave corrosive compounds. Residual amounts of sodium on components will effectively {open_quotes}solder{close_quotes} components in place, making future operation or removal unfeasible.

Michelbacher, J.A.; Earle, O.K.; Henslee, S.P. [and others

1997-12-31T23:59:59.000Z

331

Development of a commercial photovoltaic concentrator module  

SciTech Connect (OSTI)

The ojective of this work was to develop the design and prototype of a commercial high-concentration photovoltaic (PV) module. The design is for a 282-sun point-focus concentrating module. Most of the components, subassemblies, and design features incorporate simplifications and ease of manufacturing. The Solar Kinetics, Inc. (SKI) module is designed to incorporate high-efficiency, single-crystal silicon PV cells. The housing is made with aluminum laminated for voltage stand-off and simultaneously providing high thermal conductivity. The Fresnel lens injection molded by American Optical (AO) as singles. The cell assembly consists of a copper heat spreader, a photovoltaic cell soldered, a top and bottom contact, and a reflective secondary optical element (SOE). The cell assemblies passed all of the initial electrical characterization and high-potential tests. Under environmental cycling, the only bond that failed was the PV cell-to-heat spreader interface. The other components (top contact, bottom contact, SOE) passed all the environmental cycling tests. The cell assemblies were designed to be mounted onto the receiver section with a thermally conductive RTV. This geometry was subjected to environmental testing. There was no delamination of this bond nor was there electrical breakdown when the assemblies were subjected to the hi-pot test. A mock module was fabricated for environmental evaluation. This module was subjected to the humidity/freeze cycling to assess the performance of the lens mounting design. This module was also subjected to the rain test after the humidity/freeze cycling and checked for water leaks. The lens showed small displacement from its original position after the environmental cycling. One tablespoon of water did collect inside the module.

Saifee, S.T.; Hutchison, G. [Solar Kinetics, Inc., Dallas, TX (United States)

1992-09-01T23:59:59.000Z

332

Stab Sensitivity of Energetic Nanolaminates  

SciTech Connect (OSTI)

This work details the stab ignition, small-scale safety, and energy release characteristics of bimetallic Al/Ni(V) and Al/Monel energetic nanolaminate freestanding thin films. The influence of the engineered nanostructural features of the energetic multilayers is correlated with both stab initiation and small-scale energetic materials testing results. Structural parameters of the energetic thin films found to be important include the bi-layer period, total thickness of the film, and presence or absence of aluminum coating layers. In general the most sensitive nanolaminates were those that were relatively thick, possessed fine bi-layer periods, and were not coated. Energetic nanolaminates were tested for their stab sensitivity as freestanding continuous parts and as coarse powders. The stab sensitivity of mock M55 detonators loaded with energetic nanolaminate was found to depend strongly upon both the particle size of the material and the configuration of nanolaminate material, in the detonator cup. In these instances stab ignition was observed with input energies as low as 5 mJ for a coarse powder with an average particle dimension of 400 {micro}m. Selected experiments indicate that the reacting nanolaminate can be used to ignite other energetic materials such as sol-gel nanostructured thermite, and conventional thermite that was either coated onto the multilayer substrate or pressed on it. These results demonstrate that energetic nanolaminates can be tuned to have precise and controlled ignition thresholds and can initiate other energetic materials and therefore are viable candidates as lead-free impact initiated igniters or detonators.

Gash, A; Barbee, T; Cervantes, O

2006-05-22T23:59:59.000Z

333

An evaluation of chemical screening test kits for lead in paint  

SciTech Connect (OSTI)

The Residential Lead-Based Paint Hazard Reduction Act (Title X) requires abatement and management of lead-based paint. The purpose of this study was to evaluate three chemical screening test kits using materials and methods from one study and subjecting the results to the statistical analysis of another. The three kits were used to predict the presence of lead in paint at ten weight concentrations from 0.04 to 3.97%. Paint was applied to four wood boards yielding a sample size of 40. Four boards were painted with lead-free paint and used as blanks. All of the boards were tested with the three test kits by an untrained individual having no knowledge of the actual lead content. Sensitivity, specificity, and false positive and negative rates were calculated for the test kit results. The manufactures` detection limits, the observed sensitivity ranged from 1.00 to 0.80, specificity ranged from 1.00 to 0.42, false positive ranged from 0 to 58%, and false negatives ranged from 0 to 20%. At the 0.5% Federal threshold level, the observed sensitivity ranged from 1.00 to 0.94, specificity ranged from 1.00 to 0.5, false positives ranged from 0 to 11.1%, and false negatives ranged from 0 to 20%. The observed false positive and false negative rates for all three kits were found to be significantly lower than those reported in a previous study. These results indicate that the kits perform very well at the Federal threshold, with two of the kits having false negative rates below 12.5% and false positive rates of 3.13%. These results indicate that these two kits would probably be acceptable screening tests for lead in paint.

Oglesby, L.S.

1996-04-01T23:59:59.000Z

334

The effect of low Au concentrations on the properties of eutectic Sn/Pb  

SciTech Connect (OSTI)

This study was of the effects moderately low Au concentrations ({le} 10 wt%) have on the mechanical properties and microstructure of an eutectic Sn/Pb alloy. Vibration (60--90 Hz swept sine wave for 30 hours) and thermal cycling (0--110C for 1450 cycles) reliability tests were performed on fine pitch leaded chip carriers using eutectic Sn/Pb solder on PCBs (printed circuit boards) with 0, 5, 10, 20, and 50{mu}in nominal Au thicknesses. Testing was also performed on double shear creep specimens consisting of arrays of regular pitch joints. There was a dramatic increase in the number of joints containing voids with increasing Au concentration, an effect more pronounced in the creep joints than in the reliability joints. These voids tended to coalesce and grow during rework simulation of the reliability joints. AuSn{sub 4} intermetallics present in toe of 4.8 wt% (50 {mu}in) Au vibration joints rotated from initial vertical perpendicular to surface of PCB metallization, solidification positions to roughly horizontal (parallel to plating surface) orientations during rework simulation and during aging of the parts. The AuSn{sub 4} intermetallics in the toe of the 4.8 wt% (50{mu}in) Au reflowed joints also rotated after vibration testing. No joint failures were observed in either vibration tested or thermally cycled specimens. Cracks formed in some of the vibration tested specimen joints under the heel of the gull-wing lead at Pb-rich phases. Thermally cycled specimens showed eutectic microstructure and intermetallic coarsening without crack formation. Creep tests showed loss of the superplasticity in eutectic Sn/Pb alloys with even the lowest Au concentration tested of 0.2 wt% Au. Intermetallic rotation was not a factor in crack propagation, but void presence was. Cracks tended to form in joints containing voids before forming in void-free joints. Crack propagation followed Sn/Sn grain boundaries and Sn/Pb phase boundaries from Pb-rich phase to Pb-rich phase.

Kramer, P.A.

1992-05-01T23:59:59.000Z

335

Harsh environments electronics : downhole applications.  

SciTech Connect (OSTI)

The development and operational sustainment of renewable (geothermal) and non-renewable (fossil fuel) energy resources will be accompanied by increasingly higher costs factors: exploration and site preparation, operational maintenance and repair. Increased government oversight in the wake of the Gulf oil spill will only add to the cost burden. It is important to understand that downhole conditions are not just about elevated temperatures. It is often construed that military electronics are exposed to the upper limit in terms of extreme service environments. Probably the harshest of all service conditions for electronics and electrical equipment are those in oil, gas, and geothermal wells. From the technology perspective, advanced materials, sensors, and microelectronics devices are benefificial to the exploration and sustainment of energy resources, especially in terms of lower costs. Besides the need for the science that creates these breakthroughs - there is also a need for sustained engineering development and testing. Downhole oil, gas, and geothermal well applications can have a wide range of environments and reliability requirements: Temperature, Pressure, Vibration, Corrosion, and Service duration. All too frequently, these conditions are not well-defifined because the application is labeled as 'high temperature'. This ambiguity is problematic when the investigation turns to new approaches for electronic packaging solutions. The objective is to develop harsh environment, electronic packaging that meets customer requirements of cost, performance, and reliability. There are a number of challenges: (1) Materials sets - solder alloys, substrate materials; (2) Manufacturing process - low to middle volumes, low defect counts, new equipment technologies; and (3) Reliability testing - requirements documents, test methods and modeling, relevant standards documents. The cost to develop and sustain renewable and non-renewable energy resources will continue to escalate within the industry. Downhole electronics can provide a very cost-effective approach for well exploration and sustainment (data logging). However, the harsh environments are a 'game-changer' in terms defining materials, assembly processes and the long-term reliability of downhole electronic systems. The system-level approach will enable the integration of each of these contributors - materials, processes, and reliability - in order to deliver cost-effective electronics that meet customer requirements.

Vianco, Paul Thomas

2011-03-01T23:59:59.000Z

336

High-Temperature High-Power Packaging Techniques for HEV Traction Applications  

SciTech Connect (OSTI)

A key issue associated with the wider adoption of hybrid-electric vehicles (HEV) and plug in hybrid-electric vehicles (PHEV) is the implementation of the power electronic systems that are required in these products. One of the primary industry goals is the reduction in the price of these vehicles relative to the cost of traditional gasoline powered vehicles. Today these systems, such as the Prius, utilize one coolant loop for the engine at approximately 100 C coolant temperatures, and a second coolant loop for the inverter at 65 C. One way in which significant cost reduction of these systems could be achieved is through the use of a single coolant loop for both the power electronics as well as the internal combustion engine (ICE). This change in coolant temperature significantly increases the junction temperatures of the devices and creates a number of challenges for both device fabrication and the assembly of these devices into inverters and converters for HEV and PHEV applications. Traditional power modules and the state-of-the-art inverters in the current HEV products, are based on chip and wire assembly and direct bond copper (DBC) on ceramic substrates. While a shift to silicon carbide (SiC) devices from silicon (Si) devices would allow the higher operating temperatures required for a single coolant loop, it also creates a number of challenges for the assembly of these devices into power inverters. While this traditional packaging technology can be extended to higher temperatures, the key issues are the substrate material and conductor stability, die bonding material, wire bonds, and bond metallurgy reliability as well as encapsulation materials that are stable at high operating temperatures. The larger temperature differential during power cycling, which would be created by higher coolant temperatures, places tremendous stress on traditional aluminum wire bonds that are used to interconnect power devices. Selection of the bond metallurgy and wire bond geometry can play a key role in mitigating this stress. An alternative solution would be to eliminate the wire bonds completely through a fundamentally different method of forming a reliable top side interconnect. Similarly, the solders used in most power modules exhibit too low of a liquidus to be viable solutions for maximum junction temperatures of 200 C. Commonly used encapsulation materials, such as silicone gels, also suffer from an inability to operate at 200 C for extended periods of time. Possible solutions to these problems exist in most cases but require changes to the traditional manufacturing process used in these modules. In addition, a number of emerging technologies such as Si nitride, flip-chip assembly methods, and the elimination of base-plates would allow reliable module development for operation of HEV and PHEV inverters at elevated junction temperatures.

Elshabini, Aicha [University of Idaho; Barlow, Fred D. [University of Idaho

2006-11-01T23:59:59.000Z