Early interaction between Fe–Cr alloy metallic interconnect and Sr-doped LaMnO₃ cathodes of solid oxide fuel cells

The initial stages of the interaction between the Fe–Cr alloy metallic interconnect and Sr-doped LaMnO₃ (LSM) electrode of solid oxide fuel cells (SOFC) were investigated under cathodic polarization at the temperature range of 700–900 °C. Cr deposits on the Y₂O₃–ZrO₂ (YSZ) electrolyte surface increased with the polarization time. However, it was observed that at the early stages of the reaction, there is no preferential Cr deposition at the three-phase boundary areas at the LSM electrode/YSZ electrolyte interface region. With the decrease of the temperature the Cr deposition reduced significantly, probably due to the significant reduction in the partial pressure of the gaseous Cr species and the cationic diffusivities in the LSM electrode. The results clearly demonstrated that the deposition of Cr species at the LSM electrode/YSZ electrolyte is basically a chemical reaction and kinetically controlled by the nucleation reaction between the gaseous Cr species and the Mn²⁺ species generated under cathodic polarization.