Co-WO3 composite coating on ferritic stainless steel interconnects

Abstract

In order to apply Co-WO₃ composite coating to SUS 430 steel interconnects for solid oxide fuel cell (SOFC) interconnects, a combination of electrophoresis and electroplating is used, followed by thermal energy exposure to ambient temperature at 800 ℃ for up to 5 weeks. The thermal growth of the oxide scale displays a tri-layer structure with a Cr₂O₃ layer in the inner part, a CoWO₄ layer in the middle and (Co,Fe)₃O₄ and Co₃O₄ layer in the outer part. Co-WO₃ coating produces an oxide layer that not only prevents Cr₂O₃ development and outward transport of Cr species but also enhances the electrical behavior of the surface scale.