Degradation mechanisms and protective coatings for ferritic stainless-steel interconnects of solid oxide fuel cells: A review

Ferritic stainless steels (FSSs) are promising interconnect materials for solid oxide fuel cells (SOFCs). However, FSSs undergo fast thermal-oxidation during SOFC operation, generating poorly-conductive oxide scales and volatile chromium-oxides detrimental to cathodes. Developing protective coatings is crucial for inhibiting degradation of FSS-interconnects. This article starts with a brief discussion of the oxidation behavior and degradation mechanisms of FSS-interconnects, followed by a detailed review of the oxidization-resistant coatings including spinel oxides, metal oxides, and rare-earth perovskite oxides. Additionally, strengths and drawbacks of typical coating techniques like plasma spraying, slurry coating, electrophoretic deposition, and magnetron sputtering, as well as reduction/re-oxidation treatment for performance improvement are reviewed and discussed.