Oxide scale formation of modified FeCrAl coatings exposed to liquid lead

Modified FeCrAl coatings were studied with respect to their capability to form a thin protective oxide scale in liquid lead environment. They were manufactured by low pressure plasma spraying and GESA surface melting, thereby tuning the Al content. The specimens were exposed for 900 h to liquid lead containing 10−6 and 10−8 wt.% oxygen, respectively, at various temperatures from 400 to 550 °C. Threshold values for an Al content that guarantees the formation of thin protective Al-rich oxide scales are determined, dependent on the respective chromium content, on the presence of yttrium in the modified coating, and on the exposure conditions.

► Modified FeCrAl coatings show oxide scale formation when exposed to liquid lead.
► Formation of thin Al-rich oxide scales is promoted by the presence of Y.
► FeCrAlY with at least 8 wt.% Al forms thin Al-rich oxide scales.
► For low Al content, thick multilayer Fe-based oxide scales are found.