Effect of electrical current on the oxidation behavior of electroless nickel-plated ferritic stainless steel in solid oxide fuel cell operating conditions

Planar solid oxide fuel cell (SOFC) systems often employ metallic interconnects, which separate and connect individual cells in electrical series to create a stack. Coated and uncoated ferritic stainless steels (FSSs), are reported among the most promising materials currently being investigated for interconnect applications. In this study, FSS AISI 441 samples coated with electroless nickel (∼25 μm) were subjected to intermediate temperature IT-SOFC operating conditions at 700 °C for 500 h with and without the application of electrical current (0.5 Acm−2). The application of the electric current promotes Fe migration on both the cathode and the anode side. This phenomenon results in the formation of a ∼4 μm thick Fe2O3on the anode side responsible for increased ASR values. Comparative analyses of the current and no current exposures and resultant surface oxide layers, along with suspected mechanisms and implications are presented and discussed.