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Title: Conductive Protection Layers on Oxidation Resistant Alloys for SOFC Interconnect Applications

Abstract

Conductive oxide coatings are used as protection layers on metallic interconnects in SOFCs to improve their surface stability and electrical performance, as well as to mitigate or prevent chromium poisoning to cells. This paper discusses materials requirements for this particular application and summarizes our systematic study on varied conductive oxides as potential candidate materials for protection layers on stainless steel substrates. Overall, it appeared that chromites such as (La,Sr)CrO3 improved surface stability, but might not be good candidates for the protection layer applications due to chromium vaporization, albeit at a lower rate than Cr2O3, from these oxides at high temperatures in air or moist air. The application of non-chromite perovskite (La,Sr)FeO3 protection layers resulted in improved oxidation resistance and electrical performance. It is doubtful, however, that LSF can be an effective barrier to prevent chromium release during long term SOFC stack operation due to chromium diffusion through the LSF coatings. With a high oxygen ion conductivity, the coatings of Sn-doped In2O3 failed to provide protection to the metal substrate and are thus not suitable for the protection layer applications. The best performance was achieved using thermally-grown (Mn,Co)3O4 spinel protection layers that substantially improved the surface stability of the metal substrates,more » and prevented chromium outward migration.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
898640
Report Number(s):
PNNL-SA-50052
AA2530000; TRN: US200706%%246
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Surface & Coatings Technology, 201(7):4476-4483
Country of Publication:
United States
Language:
English
Subject:
30 DIRECT ENERGY CONVERSION; 36 MATERIALS SCIENCE; ALLOYS; CHROMITES; CHROMIUM; COATINGS; DIFFUSION; EVAPORATION; OXIDATION; OXIDES; OXYGEN IONS; PEROVSKITE; POISONING; SOLID OXIDE FUEL CELLS; SPINELS; STABILITY; STAINLESS STEELS; SUBSTRATES; SOFC; interconnect applications; stack operation; metallic interconnects

Citation Formats

Yang, Zhenguo, Xia, Guanguang, Maupin, Gary D., and Stevenson, Jeffry W. Conductive Protection Layers on Oxidation Resistant Alloys for SOFC Interconnect Applications. United States: N. p., 2006. Web. doi:10.1016/j.surfcoat.2006.08.082.
Yang, Zhenguo, Xia, Guanguang, Maupin, Gary D., & Stevenson, Jeffry W. Conductive Protection Layers on Oxidation Resistant Alloys for SOFC Interconnect Applications. United States. doi:10.1016/j.surfcoat.2006.08.082.
Yang, Zhenguo, Xia, Guanguang, Maupin, Gary D., and Stevenson, Jeffry W. Wed . "Conductive Protection Layers on Oxidation Resistant Alloys for SOFC Interconnect Applications". United States. doi:10.1016/j.surfcoat.2006.08.082.
@article{osti_898640,
title = {Conductive Protection Layers on Oxidation Resistant Alloys for SOFC Interconnect Applications},
author = {Yang, Zhenguo and Xia, Guanguang and Maupin, Gary D. and Stevenson, Jeffry W.},
abstractNote = {Conductive oxide coatings are used as protection layers on metallic interconnects in SOFCs to improve their surface stability and electrical performance, as well as to mitigate or prevent chromium poisoning to cells. This paper discusses materials requirements for this particular application and summarizes our systematic study on varied conductive oxides as potential candidate materials for protection layers on stainless steel substrates. Overall, it appeared that chromites such as (La,Sr)CrO3 improved surface stability, but might not be good candidates for the protection layer applications due to chromium vaporization, albeit at a lower rate than Cr2O3, from these oxides at high temperatures in air or moist air. The application of non-chromite perovskite (La,Sr)FeO3 protection layers resulted in improved oxidation resistance and electrical performance. It is doubtful, however, that LSF can be an effective barrier to prevent chromium release during long term SOFC stack operation due to chromium diffusion through the LSF coatings. With a high oxygen ion conductivity, the coatings of Sn-doped In2O3 failed to provide protection to the metal substrate and are thus not suitable for the protection layer applications. The best performance was achieved using thermally-grown (Mn,Co)3O4 spinel protection layers that substantially improved the surface stability of the metal substrates, and prevented chromium outward migration.},
doi = {10.1016/j.surfcoat.2006.08.082},
journal = {Surface & Coatings Technology, 201(7):4476-4483},
number = ,
volume = ,
place = {United States},
year = {Wed Dec 20 00:00:00 EST 2006},
month = {Wed Dec 20 00:00:00 EST 2006}
}