Metallic Thin-film Co- and Ce/Co-coated Steels as Interconnect Material in IT-SOFC

摘要

Cr vaporization, oxide scale growth, and the electrical scale resistance (ASR) were studied at 650°C on coated interconnects intended for IT-SOFC applications. The custom-made SOFC interconnect steel Sanergy HT was coated with thin-film Co- and Ce/Co-coatings and compared to the less expensive substrate steel AISI 441 which was coated with Ce/Co and a 15-20 μm thick commercial MCO-coating. All coated materials mitigated Cr vaporization, and due to the very thin chromia scales formed at the low exposure temperature, ASR values below 10 mΩcm~2 were measured for all materials after 500 h at 650°C. The results in this study show that thin-film metallic Co- and Ce/Co-coated steels show excellent properties as interconnect materials for IT-SOFCs. Thick MCO-coatings can also be used at low temperatures; however, the coating method might be a critical issue for low-temperature applications.