Coated stainless steel 441 as interconnect material for solid oxide fuel cells: Oxidation performance and chromium evaporation

Reactive Element (RE) and RE/cobalt-coated stainless steel AISI 441 was exposed at Solid Oxide Fuel Cell (SOFC) cathode conditions (850 °C in air with 3% water content) for up to 500 h. The chromium evaporation was measured by applying the denuder technique. Uncoated material exhibited severe spallation which could be successfully prevented by using cerium or lanthanum coatings. By applying double layer coatings of cerium or lanthanum in combination with cobalt the oxidation rate was decreased and the chromium volatilisation was also about 90% lower than the uncoated material.