Investigation of oxidation behaviour of AISI-430 steel interconnects in the presence of Ni–Co–CeO2 composite coating for application of solid oxide fuel cells

AISI 430 stainless steels are used as interconnects in solid oxide fuel cells. One of the problems with these steels is the migration of chromium through the chrome shell and its transfer to the cathode, resulting in contamination and reduction in the efficiency of the fuel cells. To improve the oxidation resistance of these steels, a protective coating layer can be applied on the steel surface. In this investigation, AISI 430 stainless steel was electroplated with nickel, cobalt and cerium oxide. To investigate oxidation behaviour, isothermal oxidation and cyclic oxidation were performed at 800°C. The coating on the steel surface was studied using scanning electron microscopy and X-ray diffraction. In isothermal and cyclic tests, the coated samples showed less weight gain than the uncoated samples due to the formation of NiFe2O4, CoFe2O4 spinels and NiCr2O4. These spinels prevented the outward diffusion of the chromium, improving the oxidation resistance of the steel substrate. Cyclical oxidation results showed that the coating formed on the steel surface resisted cracking and delamination.