Oxidation Behavior of NiFe 2 O 4 Spinel-Coated Interconnects in Wet Air

Ferritic stainless steels are promising materials for solid oxide fuel cell interconnect applications. However, volatilization of Cr from the Cr-containing oxide scales can result in cathode poisoning, especially in wet air, and thus greatly degrades the performances of the cell. In the present study, a protective and adhesive NiFe2O4 spinel coating was applied on a type 430 stainless steel (430SS) to isolate Cr2O3 from gas environment. The performance of the uncoated and NiFe2O4-coated samples has been evaluated in the air-7%H2O at 700, 800, and 850 °C, respectively. The bare steel lost mass at 700 and 800 °C and underwent breakaway oxidation at 850 °C after ~ 75 h, including scale spallation and Cr evaporation. The NiFe2O4 coating could significantly increase the oxidation resistance of 430SS and effectively retard the outward diffusion of Cr and inhibit the Cr evaporation.