Investigation on parabolic rate constant in presence of MnCo₂O₄, CoCr₂O₄, CoFe₂O₄ and Co₃O₄ coatings at 700°C

Oxidation resistance of solid oxide fuel cells interconnects can be ameliorated by use of a protective, effective, relatively dense and well adherent spinel coating. In this study the pack cementation method was employed to coat AISI 430 ferritic stainless steel. Isothermal oxidation and cyclic oxidation were applied at 700°C to evaluate the parabolic rate constant (kp). The formation of MnCo₂O₄, CoCr₂O₄, CoFe₂O₄ and Co₃O₄ Spinels during oxidation improved oxidation resistance. The coated samples demonstrated lower kp in each test and it indicate that the coating layer has acted as a mass barrier against the outward diffusion of cations specially Cr.