Corrosion of Cr23C6 coated Q235 steel in wet atmospheres containing Na2SO4 at 750 °C

The corrosion of a Cr23C6-coated Q235 steel was studied in environments containing Na2SO4, O2, and water vapor at 750 °C. The Cr23C6-coated sample showed parabolic weight gains during both corrosion and wet oxidation. However, the weight gain during wet oxidation was much greater than that during corrosion. Corrosion generated small quantities of Cr2O3 and Cr7C3 and changed the surface morphology of the coating from granular to scale-like. Corrosion took place on the surface, and the consumption of the Cr23C6 coating occurred very slowly. The results indicate that the Cr23C6 coating has favorable corrosion resistance.