Effects of the nickel-coated ferritic stainless steel for solid oxide fuel cells interconnects

In this study, a protective nickel layer was prepared on the SUS430 alloy substrate by the atmospheric plasma spraying technology (APS). Oxidation kinetics, area specific resistance (ASR) and interfacial microstructure of the SUS430 alloy with nickel layers as well as its elemental composition were studied under the flowing humidified hydrogen atmosphere at 800 °C to evaluate the effectiveness of the protective nickel layer. The current collector between the interconnect and the anode was optimized in this paper. Results showed that the oxide growth rate constant of the SUS430 alloy with the APS nickel layer was 1.99 × 10^-14 g² cm^-4 s^-1, which was only one fiftieth of that of the alloy without a protective layer. The ASR of the SUS430 alloy with the APS nickel layer was 12 mΩ cm² after being oxidized under the simulated SOFC anode operating atmosphere at 800 °C for 250 h. With the optimized structure of current collector, the contact ASR between the nickel-coated interconnect and the Ni-YSZ anode was only 3 mΩ cm² after being oxidized at 800 °C for 100 h.