Preparation and performances of Cu Co spinel coating on ferritic stainless steel for solid oxide fuel cell interconnect

Abstract A compact and adherent Co Cu spinel coating on ferritic stainless steel was developed by electroplating a Co Cu alloy layer followed by oxidation. The Co Cu alloy was oxidized into a three-layer structure consisted of a thinner CuO outer layer, a middle thicker Cu 0.92 Co 2.08 O 4 layer and an inner Co 3 O 4 layer after an oxidation treatment of 2 h at 800 °C in air. The three-layer oxide structure was transformed into a double-layer scale with a (Co,Cr,Cu,Mn,Fe) 3 O 4 spinel outer layer and an inner Cr-rich oxide layer after an oxidation of 500 h at 800 °C in air. The Cu Co coating enhanced the oxidation resistance of the alloy and served as a diffusion barrier against the outward migration of Cr elements. Meanwhile, the area specific resistance (ASR) of the scale for the Cu Co coated alloy was significantly lower than that for the bare sample.