Corrosion of austenitic alloys in high temperature supercritical carbon dioxide

Corrosion of three austenitic alloys, 316SS and 310SS and Alloy 800H in supercritical CO2 at 650 °C and 20 MPa for 3000 h is studied. The corrosion performance of them was evaluated by weight change measurements, and the surface oxide layers were characterized and identified by SEM, XRD and XPS. Alloy 800H exhibited the best corrosion resistance followed by 310SS and 316SS. The oxidation of Alloy 800H and 310SS followed a diffusion controlled parabolic growth law. 316SS exhibited a higher oxide growth rate with more pronounced oxide spallation. Carburized regions were observed underneath the oxide layers and appeared to promote oxide spallation.