Decrease of electrical conductivity activation energy of Co-coated AISI 430 alloy

Abstract

The application of conductive coatings on ferritic stainless steel can decrease electrical conductivity. The aim of this research was to investigate the electrical conductivity of cobalt coated AISI 430 ferritic stainless steel by pack cementation technique. Coated coupons were analyzed using scanning electron microscopy (SEM). Electrical conductivity of the coated substrates was measured as a function of temperature by oxidizing the samples from room temperature to 700ºC. Also electrical conductivity has been measured as a function of oxidation time during isothermal oxidation at 700ºC. Results showed the increase of temperature caused to the decrease of electrical conductivity and also, the coating layer converted to cobalt spinels during annealing in isothermal oxidation. The formation of MnCo2O4, CoCr2O4, CoFe2O4 and Co3O4 spinels improved electrical conductivity activation energy of coated substrates (0.03 eV) compared to uncoated substrates (0.039 eV).