Compatibility of perovskite contact layers between cathode and metallic interconnector plates of SOFCs

From the viewpoint of corrosion resistance alumina and chromia forming alloys are potential candidate materials for SOFC interconnector plates. However, at the SOFC operating temperatures of around 950 degrees C the first-mentioned alloy type tends to form electrically insulating oxide scale at the interfaces between the interconnector and the ceramic contact layer, the interface oxide consisting of Al2O3 and M(2)O(3+/-x)-nAl(2)O(3). Chromium-based oxide dispersion strengthened (ODS) alloys are more suitable for SOFC applications because the chromia-based scale forming at the interfaces with the contact layers has much higher electronic conductivity than the alumina-based scale. However, upon high-temperature exposure, the composition of the ceramic contact layers is significantly changed due to solid state and vapour phase chromium transport from the alloy into the contact layer, Coatings might be necessary to prevent this degradation mechanism.