Interaction between metallic interconnect and constituent oxides of (La, Sr)MnO₃ coating of solid oxide fuel cells

The chemical interaction between Fe-Cr alloy interconnect and constituent oxides of Sr-doped LaMnO₃ (LSM) coating, La₂O₃, SrO and Mn₂O₃, is investigated at 800-900 °C in air. The Cr deposition reaction between the Fe-Cr alloy metallic interconnect and oxides varies significantly with the nature of the oxides. The interaction between the Fe-Cr alloy and La₂O₃ and Mn₂O₃ oxide coatings primarily results in the formation of LaCrO₃ and (Cr, Mn)₃O₄ while in the case of SrO oxide coating, Cr₂O₃ is the main product. In the case of LSM coating, the formation of (Cr, Mn)₃O₄ and Cr₂O₃ is identified. The results indicate that the chemical interaction between the Fe-Cr alloy interconnect and LSM coating is most likely related to the surface oxide species such as SrO and MnO_x initially enriched or segregated on the surface of LSM particularly in the early stages of the reaction.