Effect of CeO2 on oxidation and electrical behaviors of ferritic stainless steel interconnects with NiFe coatings

Ferritic stainless steels are promising materials for application in interconnects of solid oxide fuel cells (SOFC). The present problems to be solved urgently for using ferritic stainless steels as interconnects are their rapid increase in electrical resistance and the cathode poisoning caused by evaporation of chromia. In the present study, the NiFe and NiFeCeO2 alloy coatings have been electro-deposited onto 430 stainless steels (430SS). During oxidation at 800 °C in air, an outer dense NiFe2O4 layer and an inner protective Cr2O3 layer have thermally grown on the coated samples. The NiFe2O4 layer retards the outward migration of chromium effectively. The addition of CeO2 reduces the growth rate of Cr2O3 and decreases the number of pores near the oxide scale/alloy interface. Moreover, a higher electrical conductivity has been achieved by the addition of CeO2.