Oxidation Behavior of T92 Steel in High-temperature Water-vapor Atmosphere

Objective To investigate the oxidation behavior of T92 steel in 90% Ar + 10% H2O atmosphere at 750℃. Methods High-temperature oxidation experiments were conducted in a tube furnace. The morphology,microstructures and composition of oxide films were examined by SEM / EDS and XRD. Results The main oxide was composed of Fe2O3 and FeCr2O4 at the early oxidation stage in high-temperature water vapor environment. Then at the further oxidation stage,Fe ions diffused outwardly,resulting in accelerated oxidation. The oxidation scales consisted of two layers,a porous Fe2O3 outer layer and a Cr-rich inner layer. Voids existed in both layers. Some cracks between the inner and outer layers were observed. Conclusion A protective Cr-rich oxide film was not formed in the early oxidation stage. Therefore,T92 steel suffered from oxidation in water-vapor atmosphere at high temperature.