CuFe2O4 protective and electrically conductive coating thermally converted from sputtered CuFe alloy layer on SUS 430 stainless steel interconnect

Abstract

An inexpensive CuFe alloy layer with an atomic ratio (1:2) of Cu to Fe is coated on SUS 430 stainless steels via magnetron sputtering for solid oxide fuel cells interconnect application. The coated steels are thermally exposed to air at 800 °C for 15 weeks. The CuFe alloy layer is converted to CuFe2O4 spinel layer atop Cr2O3 layer developed from steel substrate. The outer layer of CuFe2O4 spinel not only retards Cr outward migration and reduces oxidation rate but also significantly lowers area specific resistance of the surface scale which is predicted for solid oxide fuel cells lifetime by a parabolic law. The sputtered CuFe alloy layer demonstrates a promising prospect for the application of steel interconnects coatings.