Thin films of La_(0.7)Sr_(0.3)MnO_(3-δ) dip-coated on Fe-Cr alloys for SOFC metallic interconnect

摘要

La_(0.7)Sr_(0.3)MnO_(3-δ), (LSM) porous films were deposited on different ferritic stainless steels (SS) (430: Cr-16.0%; 439: Cr-16.6%; 444: Cr-17.4%) by sol-gel/dip-coating process. The structure, morphology and composition profiles of investigated assemblies were examined using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray analysis. The area specific resistance (ASR) was measured during long term oxidation in air at 800 ℃ for 200 h by DC measurements. ASR values lower than 10 mil cm2 were recorded after 200 h for LSM-coated SS439 and SS444. This is likely to be due to the high Cr content and to Nb, Ti and Mo elements used to stabilize the stainless steel against oxidation. This paper shows that LSM coatings provide an enhanced stability of the alloy at high temperature and the formation of an interfacial Cr-Mn spinel layer hinders the oxide scale growth.