6533b861fe1ef96bd12c4daa

RESEARCH PRODUCT

Investigation of La2O3 and/or (Co,Mn)3O4 deposits on Crofer22APU for the SOFC interconnect application

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International audience; Chromia forming alloys (stainless steels) are among the best candidates for SOFC interconnects. However, problems of decreasing electronic conductivity during high temperature service and volatility of chromium oxide scales need to be solved. Electronically conductive surface coatings, which also reduce oxide scale growth and chromium volatility, are needed to improve stainless steel interconnects. The goal of this study is to investigate combinations of lanthanum oxide (La2O3) and cobalt manganese oxide ((Co,Mn)3O4) coatings on Crofer22APU stainless steel. Thin film coatings of La2O3 (~200 nm) and Co,Mn (1:1) (~2 mm) were deposited via metal organic chemical vapor deposition and magnetron sputtering, respectively. Three types of coatings were investigated: La2O3; (Co,Mn)3O4 (formed by a 100 h, 800 °C air anneal of Co,Mn); and, a combination coating composed of an air annealed La2O3 followed by a (Co,Mn)3O4 layer. Oxidation experiments were performed at 800 °C in air for both 100 and 1000 h and in dual environment (Air+3%H2O/H2+3%H2O) for 100 h. The combination coatings were observed to inhibit both the formation of chromia (compared to the single (Co,Mn)3O4 layer) and the formation of iron oxide in dual atmosphere (compared to the single La2O3). These and other results and interpretations are presented and discussed here.