Sol–gel coatings to reduce oxide growth in interconnects used for solid oxide fuel cells

Ferritic stainless steels (16–18 wt.% Cr) can be used as interconnects for solid oxide fuel cells (SOFC) that operate at lower temperatures, i.e., <800 °C. Long-term reliability is a concern; however, as oxidation of the steel can occur readily at elevated temperatures leading to the formation of Cr2O3 and Cr–Mn spinel ((Cr,Mn)3O4). The aim of this work was to reduce oxide growth, in particular, the Cr2O3 phase, through the application of Y/Co and Ce/Co sol–gel coatings. Oxide growth was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Coatings containing Y/Co provided the best resistance, producing Cr2O3 oxide layers more than 3 times thinner than for uncoated steels.