Evaluation of electroplated copper coating on ferritic stainless steel for solid oxide fuel cells interconnects

A Cu coating was deposited on SUS 430 ferritic stainless steel by a low-cost method of electroplating which was employed for the protection of solid oxide fuel cell metallic interconnects. After oxidation, a two-layer oxide scale consisting of an external layer of CuO and an internal layer of Cr2O3 was primarily formed on the coated steel, and a spinel layer consisting of Cu, Cr, Fe and Mn was formed at the CuO/Cr2O3 interface. The CuO outer layer not only suppressed the Cr2O3 scale growth but also served as an effective obstacle against Cr outward diffusion. The coated steels had lower scale area-specific resistances (ASRs) compared to the uncoated steel. The oxidation mechanism and surface scale electrical properties of the coated steel were discussed.