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Title: Corrosion Resistance of Amorphous Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 coating - a new criticality-controlled material

Abstract

An iron-based amorphous metal with good corrosion resistance and a high absorption cross-section for thermal neutrons has been developed and is reported here. This amorphous alloy has the approximate formula Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} and is known as SAM2X5. Chromium (Cr), molybdenum (Mo) and tungsten (W) were added to provide corrosion resistance, while boron (B) was added to promote glass formation and the absorption of thermal neutrons. Since this amorphous metal has a higher boron content than conventional borated stainless steels, it provides the nuclear engineer with design advantages for criticality control structures with enhanced safety. While melt-spun ribbons with limited practical applications were initially produced, large quantities (several tons) of gas atomized powder have now been produced on an industrial scale, and applied as thermal-spray coatings on prototypical half-scale spent nuclear fuel containers and neutron-absorbing baskets. These prototypes and other SAM2X5 samples have undergone a variety of corrosion testing, including both salt-fog and long-term immersion testing. Modes and rates of corrosion have been determined in various relevant environments, and are reported here. While these coatings have less corrosion resistance than melt-spun ribbons and optimized coatings produced in the laboratory, substantial corrosion resistance has beenmore » achieved.« less

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1018788
Report Number(s):
UCRL-JRNL-229505
TRN: US1103464
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Nuclear Technology, vol. 161, no. 2, March 1, 2008, pp. 169-189; Journal Volume: 161; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ALLOYS; BORON; CHROMIUM; COATINGS; CONTAINERS; CORROSION; CORROSION RESISTANCE; CRITICALITY; DESIGN; ENGINEERS; GLASS; MOLYBDENUM; NUCLEAR FUELS; SAFETY; STAINLESS STEELS; TESTING; THERMAL NEUTRONS; TUNGSTEN

Citation Formats

Farmer, J C, Choi, J S, Saw, C K, Rebak, R, Day, S D, Lian, T, Hailey, P, Payer, J H, Branagan, D J, and Aprigliano, L F. Corrosion Resistance of Amorphous Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 coating - a new criticality-controlled material. United States: N. p., 2007. Web.
Farmer, J C, Choi, J S, Saw, C K, Rebak, R, Day, S D, Lian, T, Hailey, P, Payer, J H, Branagan, D J, & Aprigliano, L F. Corrosion Resistance of Amorphous Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 coating - a new criticality-controlled material. United States.
Farmer, J C, Choi, J S, Saw, C K, Rebak, R, Day, S D, Lian, T, Hailey, P, Payer, J H, Branagan, D J, and Aprigliano, L F. Wed . "Corrosion Resistance of Amorphous Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 coating - a new criticality-controlled material". United States. doi:. https://www.osti.gov/servlets/purl/1018788.
@article{osti_1018788,
title = {Corrosion Resistance of Amorphous Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 coating - a new criticality-controlled material},
author = {Farmer, J C and Choi, J S and Saw, C K and Rebak, R and Day, S D and Lian, T and Hailey, P and Payer, J H and Branagan, D J and Aprigliano, L F},
abstractNote = {An iron-based amorphous metal with good corrosion resistance and a high absorption cross-section for thermal neutrons has been developed and is reported here. This amorphous alloy has the approximate formula Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} and is known as SAM2X5. Chromium (Cr), molybdenum (Mo) and tungsten (W) were added to provide corrosion resistance, while boron (B) was added to promote glass formation and the absorption of thermal neutrons. Since this amorphous metal has a higher boron content than conventional borated stainless steels, it provides the nuclear engineer with design advantages for criticality control structures with enhanced safety. While melt-spun ribbons with limited practical applications were initially produced, large quantities (several tons) of gas atomized powder have now been produced on an industrial scale, and applied as thermal-spray coatings on prototypical half-scale spent nuclear fuel containers and neutron-absorbing baskets. These prototypes and other SAM2X5 samples have undergone a variety of corrosion testing, including both salt-fog and long-term immersion testing. Modes and rates of corrosion have been determined in various relevant environments, and are reported here. While these coatings have less corrosion resistance than melt-spun ribbons and optimized coatings produced in the laboratory, substantial corrosion resistance has been achieved.},
doi = {},
journal = {Journal of Nuclear Technology, vol. 161, no. 2, March 1, 2008, pp. 169-189},
number = 2,
volume = 161,
place = {United States},
year = {Wed Mar 28 00:00:00 EDT 2007},
month = {Wed Mar 28 00:00:00 EDT 2007}
}
  • An iron-based amorphous metal, Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4} (SAM2X5), with very good corrosion resistance was developed. This material was produced as a melt-spun ribbon, as well as gas atomized powder and a thermal-spray coating. Chromium (Cr), molybdenum (Mo) and tungsten (W) provided corrosion resistance, and boron (B) enabled glass formation. The high boron content of this particular amorphous metal made it an effective neutron absorber, and suitable for criticality control applications. Earlier studies have shown that ingots and melt-spun ribbons of these materials have good passive film stability in these environments. Thermal spray coatings ofmore » these materials have now been produced, and have undergone a variety of corrosion testing, including both atmospheric and long-term immersion testing. The modes and rates of corrosion have been determined in the various environments, and are reported here.« less
  • Several Fe-based amorphous metals were developed with good corrosion resistance. These materials have been produced as melt-spun ribbons, ingots, and thermal-spray coatings. Cyclic polarization has been conducted in several aggressive environments, at ambient temperature, as well as temperatures approaching the boiling points of the test solutions. The hypothesis that the corrosion resistance of iron-based amorphous metals can be enhanced through application of heuristic principles related to the additions of chromium, molybdenum, tungsten has been tested and found to have merit. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such asmore » yttrium (Y) lower critical cooling rate (CCR). The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature.« less
  • The corrosion behavior of electrodeposited Ni-P, Ni-W, Ni-W-P, and Fe-W alloys was tested, and the effects of the additive elements W and P on the corrosion resistance of amorphous deposits were studied. Corrosion rates of the alloys were compared to those of stainless steel. Results showed the W content in electrodeposited Ni-W-P amorphous alloy was as high as 55.2 wt%. The hardness (Vickers [HV]) of the alloy was from 700 HV to 800 HV and 1,300 HV to 1,400 HV after heat treatment at 550 C. The hardness, wear resistance, and corrosion resistance of the deposit were shown to bemore » superior to those of Ni-P amorphous deposit. The corrosion potential was moved to noble by adding P to the deposit, and the passive current density dropped remarkably with the addition of W. Amorphous Ni-W, Ni-W-P, and Fe-W alloy deposits showed high corrosion resistance in acid solutions. Immersion tests in 1 mol/L hydrochloric acid solution t 30 C showed the corrosion rate of type 304 stainless steel was 10 times that of Ni-W-P amorphous deposit, 40 times that of Ni-W amorphous deposit, and 15 to 20 times that of Fe-W amorphous deposit. In 0.5 mol/L sulfuric acid solution at 30 C, the corrosion resistance of the amorphous deposit was poorer than that of type 304 SS, but at 60 C, the corrosion rate of type 304 SS increased dramatically, to 180 times that of Fe-W amorphous deposit and 100 to 700 times that of the Ni-based amorphous deposit.« less
  • New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative thermal phase stability, microstructure, mechanical properties, damage tolerance, and corrosion resistance. Some alloy additions are known to promote glass formation and to lower the critical cooling rate [F. Guo, S. J. Poon, Applied Physics Letters, 83 (13) 2575-2577, 2003]. Other elements are known to enhance the corrosion resistance of conventional stainless steels and nickel-based alloys [A. I. Asphahani, Materials Performance, Vol. 19, No. 12, pp. 33-43, 1980] and have been found to provide similar benefits to iron-based amorphousmore » metals. Many of these materials can be cast as relatively thick ingots, or applied as coatings with advanced thermal spray technology. A wide variety of thermal spray processes have been developed by industry, and can be used to apply these new materials as coatings. Any of these can be used for the deposition of the formulations discussed here, with varying degrees of residual porosity and crystalline structure. Thick protective coatings have now been made that are fully dense and completely amorphous in the as-sprayed condition. An overview of the High-Performance Corrosion Resistant Materials (HPCRM) Project will be given, with particular emphasis on the corrosion resistance of several different types of iron-based amorphous metals in various environments of interest. The salt fog test has been used to compare the performance of various wrought alloys, melt-spun ribbons, arc-melted drop-cast ingots, and thermal-spray coatings for their susceptibility to corrosion in marine environments. Electrochemical tests have also been performed in seawater. Spontaneous breakdown of the passive film and localized corrosion require that the open-circuit corrosion potential exceed the critical potential. The resistance to localized corrosion is seawater has been quantified through measurement of the open-circuit corrosion potential (E{sub corr}), the breakdown potential (E{sub crit}) and the repassivation potential (E{sub rp}). The greater the difference between the open-circuit corrosion potential and the repassivation potential ({Delta}E), the more resistant a material is to modes of localized corrosion such as pitting and crevice corrosion. Cyclic polarization (CP) was used as a means of measuring the critical potential (E{sub crit}) relative to the open-circuit corrosion potential (E{sub corr}). Linear polarization (LP) has been used to determine the corrosion current (i{sub corr}) and the corresponding corrosion rate. Other aspects of the materials will also be discussed, as well as potential applications.« less