Study of Iron-Based Alloys in Solid Oxide Fuel Cell Temperature and Atmosphere Conditions, Effect of a Silver-Coating

The French Atomic Energy Commission has developed a High Temperature Electrolyzer having an original coaxial architecture. Important elements are spring-like interconnects which allow to cope with thermal dilatation. Specifications of these components are low-cost, long term electrical conductivity achieved by chemical and mechanical stability. Potential candidates are iron-based alloys on which thin silver-coating may be deposited. In this paper we study the interaction of such systems with a mixture of hot vapour and hydrogen that is representative of the electrolyzer environment. Oxidation kinetic is measured by thermogravimetry. The oxide layer composition and morphology of tested samples are then investigated using Energy Dispersive Spectroscopy (EDS) and Auger Electron Spectroscopy (AES). These analyses demonstrate that hydrogen content strongly impacts the oxidation mechanism.