Oxidation behavior of ferritic steel alloy coated with highly dense conducting ceramics by aerosol deposition

Conducting La0.8Sr0.2MnO3 (LSM) ceramic layers with a thickness of similar to 10 mu m were deposited on ferritic stainless steel (SS) by aerosol deposition for use as an oxidation resistance coating layer in the metallic interconnects of solid oxide fuel cell. The microstructural evolution and electrical properties of the LSM-coated SS were observed. The coated layers were fairly dense without pores or cracks, and maintained good adhesion even after oxidation at 800 degrees C for 1000 h in air atmosphere. The surface of the bare SS after heat treatment at 800 degrees C for 1000 h was covered with Cr-containing oxide scales, and the electrical conductivity was sharply decreased. However, the LSM-coated SS alloy showed a surface microstructure with almost no chromic oxide formation and maintained good electrical conductivity after the heat treatment. Close observation of the interface between LSM and SS indicated the presence of similar to 500-nm-thick Cr2O3 and MnCr2O4 spinel phase, which may have caused the long-time deterioration of the interconnector performance. The area-specific resistance of the LSM-coated alloy after heat treatment at 800 degrees C for 1000 h was 10.4 m Omega.cm(2).