Development of Protective Coatings for SOFC Metallic Components

Abstract

The adoption of oxidation resistant, high-temperature alloys as alternatives to traditional ceramic interconnect materials for intermediate-temperature solid oxide fuel cells is critical to satisfy the aggressive cost targets necessary for their successful development. The effect of processing conditions on the microstructure and electrical performance of manganese cobaltite oxide coatings for the protection of ferritic stainless steel interconnects has been investigated. Using the standard aerosol spray deposition (ASD) based process which includes a reduction firing operation a highly dense MCO coating is formed that acts as an effective barrier to high temperature oxidation and chromium volatilization. Excellent long-term electrical and microstructural stability of the MCO coating has been demonstrated under application specific conditions. Omitting the reduction firing step is shown to significantly degrade the coating microstructure which is unable to densify sufficiently to form an effective protective oxide coating.