Corrosion of Iron in Molten Carbonates at 650°C

Abstract

In order to define the mechanisms that control the corrosion of current collector materials in molten carbonate fuel cells, the corrosion of iron with melts at 650°C was investigated. Thermochemical calculations were used to identify equilibrium corrosion products and establish phase stability diagrams for the Fe‐Li‐K‐C‐O system. The corrosion of iron with a 2.0 mg/cm2 carbonate deposit of under proceeded according to a parabolic rate law, where the corrosion rate was controlled by the diffusion of iron cations through and inner layers. The corrosion of iron with the carbonate deposit under Pa followed a linear rate, where the controlling step was the dissolution of oxygen from the gas phase into the carbonate. With the aid of the phase stability diagrams, the corrosion kinetics and scale morphologies were examined.