Oxidation and Electrical Properties of Cu-Mn3O4 Composite Coating Obtained by Electrodeposition on SOFC Interconnects

Cu-Mn3O4 composite coating was prepared on the SUS 430 ferritic stainless steel by electrodeposition and then exposed in air at 800 degrees C corresponding to the cathode atmosphere of solid oxide fuel cell (SOFC). A dual-layer oxide structure mainly comprising an external layer of CuO followed by (Cu,Mn,Fe)(3)O-4 spinel and an internal layer of Cr-rich oxide was thermally developed on the coated steel. The scale area-specific resistances (ASRs) of the coated steels were lower than the scale ASR of the uncoated steel after identical thermal exposure. The external layer of CuO/(Cu,Mn,Fe)(3)O-4 spinel not only served as a barrier to reduce the growth rate of Cr-rich oxide internal layer and to suppress the outward diffusion of Cr, but also lowered the surface scale ASRs considerably.