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Title: Systematic Evaluation of Jc Decrease in Thick Film Coated Conductors

Abstract

Address both thickness dependence of Jc, in thick film YBCO coated conductors through an application of a suite of new measurement techniques to thick film wire samples produced by commercially viable coated conductor technologies.

Authors:
;
Publication Date:
Research Org.:
University of Houston
Sponsoring Org.:
USDOE
OSTI Identifier:
885091
Report Number(s):
DOE/ID/14512
TRN: US200719%%187
DOE Contract Number:
FC07-03ID14512
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; THICKNESS; YTTRIUM OXIDES; BARIUM OXIDES; COPPER OXIDES; COATINGS; THERMODYNAMIC PROPERTIES

Citation Formats

Alex Ignatiev, and Dr. Amit Goyal. Systematic Evaluation of Jc Decrease in Thick Film Coated Conductors. United States: N. p., 2006. Web. doi:10.2172/885091.
Alex Ignatiev, & Dr. Amit Goyal. Systematic Evaluation of Jc Decrease in Thick Film Coated Conductors. United States. doi:10.2172/885091.
Alex Ignatiev, and Dr. Amit Goyal. Wed . "Systematic Evaluation of Jc Decrease in Thick Film Coated Conductors". United States. doi:10.2172/885091. https://www.osti.gov/servlets/purl/885091.
@article{osti_885091,
title = {Systematic Evaluation of Jc Decrease in Thick Film Coated Conductors},
author = {Alex Ignatiev and Dr. Amit Goyal},
abstractNote = {Address both thickness dependence of Jc, in thick film YBCO coated conductors through an application of a suite of new measurement techniques to thick film wire samples produced by commercially viable coated conductor technologies.},
doi = {10.2172/885091},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 10 00:00:00 EDT 2006},
month = {Wed May 10 00:00:00 EDT 2006}
}

Technical Report:

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  • The primary thrusts of our work were to provide critical understanding of how best to enhance the current-carrying capacity of coated conductors. These include the deconstruction of Jc as a function of fim thickness, the growth of in situ films incorporating strong pinning centers and the use of a suite of position-sensitive tools that enable location and analysis of key areas where current-limiting occurs.
  • The fabrication and operation of membrane switches are discussed. The membrane switch functions as a normally open, momentary contact, low-voltage pressure-sensitive device. Its design is a three-layer sandwich usually constructed of polyester film. Conductive patterns are deposited onto the inner side of top and bottom sheets by silk screening. The center spacer is then placed between the two circuit layers to form a sandwich, generally held together by an adhesive. When pressure is applied to the top layer, it flexes through the punched openings of the spacer to establish electrical contact between conductive pads of the upper and lower sheets,more » momentarily closing the circuit. Upon release of force the top sheet springs back to its normal open position. The membrane touch switch is being used in a rapidly expanding range of applications, including instrumentation, appliances, electronic games and keyboards. Its board acceptance results from its low cost, durability, ease of manufacture, cosmetic appeal and design flexibility. The principal electronic components in the membrane switch are the conductor and dielectric.« less
  • YBCO-based Coated Conductors (CC) are touted as the next generation of high current=carrying capacity High Temperature Superconductors (HTS) wires. If commercially viable, CC will signal a revolution in power trnasmission, with enormous economic consequences. It has been recently reported that the observed ciritical current in such CC is decreasing with the fil thickness d, roughly as d-1/2. The origin of this decrease is not understood. This work is aimed at developing a simple model to explain this feature.
  • 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, themore » 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.« less