Effect of slurry-coated LaSrMnO3 on the electrical property of Fe-Cr alloy for metallic interconnect of SOFC

The effect of (La0.85Sr0.15)(0.9)MnO3 (LSM) coating layer on the electric properties of the Fe-16Cr alloy (SUS430) and Fecralloy((R)) was examined in air. The LSM layer was coated on the Fe-Cr alloys by slurry-dipping process and was sintered at 1200 degreesC. When the LSM-coated SUS 430 was sintered in Ar atmosphere with H-2, the phase separation of the LSM coating layer was observed, which increased the area specific resistance. The decomposed LSM phase changed to a stable phase with increasing the holding time at 750 degreesC in air. When the LSM-coated SUS430 was heat-treated in air at 1000 degreesC after the sintering, the stable LSM-coated SUS 430 showed a low area-specific resistance (ASR) and maintained almost a constant value for 2600 h. The area specific resistances of the LSM-coated Fe-Cr alloys depend on the interfacial oxide layer formed between LSM and alloys. The LSM-coated Fecralloy((R)) showed a much larger area-specific resistance due to the formation of Al-rich mixed interfacial oxide. It is concluded that the LSM-coated Fecralloy((R)) made by sintering process is not adequate for metallic interconnect. (C) 2004 Elsevier B.V. All rights reserved.