Corrosion of metallic stack components in molten carbonates: Critical issues and recent findings

The influence of stainless steel hardware corrosion on molten carbonate fuel cell (MCFC) cell performance decay modes is briefly reviewed. Emphasis has been given to the cathode-side corrosion of the separator plate, which is the most critical performance-limiting factor due to the growth of thick oxide scales with a poor electrical conductivity causing relevant cell voltage losses on prolonged operations. Voltage decay is related to loss of electrolyte by reaction with the growing oxide scale and to the onset of an ohmic resistance at the point of contact between the corroded separator plate and the cathode. The increase of ohmic resistance over the time is the major cause of voltage decay with the currently used austenitic 316L and 310S stainless steels. A short literature survey is presented in the second part of this paper reporting on the most promising alternative corrosion-resistant alloys or protective coatings suitable for fabrication of long-term stable cathode-side MCFC separator plates.