Publication in the journal “High Temperature Corrosion of Materials” (Peer-reviewed) Microstructure of Cr 2 O 3 Scales Grown in Ar-5H 2 O-(5H 2 ) at 850 o C

Abstract Model alloy, Fe-20Cr (wt.%), was oxidized in two gas mixtures Ar-5H₂O-(5H₂) (vol.%) at 850 oC. The alloy formed Cr₂O₃ scales in both gases. The Cr₂O₃ scale developed faster in Ar-5H₂O-5H₂ and contained fine pores, whilst that grown in Ar-5H₂O was dense. Experiments with inert SiO₂ marker revealed that the Cr₂O₃ scale growth in Ar-5H₂O-(5H₂) was controlled mainly by outward Cr diffusion. When adjusted for grain boundary diffusion effects, Wagner’s theory was successful in describing the hydrogen effect, provided that the Cr₂O₃ scales are n-type.