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In order to define the mechanisms that control the corrosion of current collector materials in molten carbonate fuel cells, the corrosion of iron with Li2CO3‐K2CO3 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 false(Li0.62K0.38)2CO3 under 20%O2‐false(0.01–50false)%CO2‐normalAr proceeded according to a parabolic rate law, where the corrosion rate was controlled by the diffusion of iron cations through normalFeO and Fe3O4 inner layers. The corrosion of iron with the carbonate deposit under Po2<102 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.

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Porous Ni/ZrO2-Y203 cermets are electronically con~ ducting at Ni contents greater than 30 v/o of total solids. Below this level, the conductivity falls to that of the ionically conducting zirconia matrix. The 30 v/o value was found to be independent of the zirconia particle size for the two sizes studied. Nevertheless, considerable improvement in the electronic conduction of the cermet (Ni content > 30 v/o) was made by increasing the zirconia particle size. This improvement probably results from better Ni particle-to-particle contact.

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