Stability of Haynes 242 as metallic interconnects of solid oxide fuel cells (SOFCs)

Haynes 242 is a unique Ni based alloy for interconnect application of solid oxide fuel cells (SOFCs), due to its low CTE (coefficient of thermal expansion) value which matches other fuel cell components over its peer of other Ni based alloys, together with very excellent oxidation resistance, and electrical conductive nature of the thermally grown oxide scales. A Ni–Mo rich intermetallic phase was observed to precipitate in this alloy during the thermal exposure in the SOFC environments and cause stability issue. This paper examined the stability of Haynes 242 in terms of oxidation resistance, electrical property, and oxidation kinetics as interconnects of solid oxide fuel cells. Results indicated that the precipitation helped significantly towards formation of NiO to reduce the Cr evaporation, and influenced little on oxidation resistance and electrical property.