Studies on electrical resistance activation energy in presence of cobalt spinels

Abstract

The formation of oxide layer on the surface of used interconnects in solid oxide fuel cells (SOFCs), decrease the electrical conductivity and therefore energy losses can be occurred. The electrical conductivity of ferritic stainless steels can be improved by applying a protective/ conductive layer. In this study pack cementation method was employed to coat the AISI 430 ferritic stainless steel. Isothermal oxidation was applied at 700ºC for 200 h to evaluate the area specific resistance (ASR) values. Electrical resistance activation energy was evaluated by use of previous consequences. The formation of MnCo2O4, CoCr2O4, CoFe2O4 and Co3O4 spinels during oxidation improved oxidation resistance and electrical conductivity. Results showed that the activation energy decreased when the temperature decreased and the coated samples electrical resistance activation energy (0.026eV) was lower than uncoated ones (0.033eV).