Oxidation behavior of coated and preoxidized ferritic steel in single and dual atmosphere exposures at 800 °C

► We subjected preoxidized and coated Crofer 22APU to single and dual atmosphere exposures ► Different ionic transport phenomena were observed in single vs. dual atmosphere exposures ► The CoMn coating leads to the creation of mixed CoMnFe oxides ► Pre-oxidation inhibits Fe surface migration, and reduces negative effects of hydrogen permeation through the alloy.