Comparison of Ce/Co and Ce/FeNi coatings for interconnects in solid oxide electrolysis

Journal article, 2026

Manganese Cobalt oxide (MCO) coatings have been extensively studied for interconnect applications in solid oxide fuel cells (SOFC). Nevertheless, Co is a critical raw material and efforts are taken to replace it. Ce/FeNi coatings are proposed as an alternative and compared to Ce/Co on AISI 441. Chromium evaporation behaviour, oxidation kinetics, interfacial fracture energy, and area-specific resistance (ASR) of the coating and steels were investigated for up to 3,850 h at 850 °C. Ce/FeNi coatings were not found to be as effective as Ce/Co coatings in preventing chromium evaporation. Nevertheless, Ce/FeNi coated steels showed 50 % lower parabolic rate constant and ASR than Ce/Co coated steel. Additionally, the fracture energy of the adherence of the Ce/FeNi coating to the steel was measured at 750 and 850 °C. The Ce/FeNi coating adherence to the steel greatly outperformed the Ce/Co coating adherence. Furthermore, while the fracture energy of the Ce/Co coating decreases with exposure time, it increases over time for the Ce/FeNi coating.