Influence of Mn-Co Spinel Coating on Oxidation Behavior of Ferritic SS Alloys for SOFC Interconnect Applications

摘要

Chromia forming ferritic stainless steels (SS) are being considered for intermediate temperature solid oxide fuel cell interconnect applications. However, protective coatings are in general needed to avoid chromium volatilization and poisoning of cathodes from chromium species. Mn-Co spinel is one of the promising candidates to prevent chromium outward diffusion, improve oxidation resistance and ensure high electrical conductivity over the lifetime of interconnects. In the present study, uniform and well adherent Mn-Co spinel coatings were produced on Crofer 22APU using electrophoretic deposition (EPD). The oxidation behavior of both the coated and bare alloy was evaluated at 800°C in air for 1000 h. The oxidation kinetics were investigated using weight gain and scale thickness measurements. The weight gain per unit surface area of the bare alloy exhibited parabolic oxidation behavior. The influence of Mn-Co spinel coating on chromia scale formation and corrosion rate of different ferritic stainless steels is also elucidated.