Effect of Coating on the Oxidation Behavior of Turbine Rotor Material in Supercritical Water

High-temperature oxidation behavior of IBN-1 alloy, Ni-Cr thermally sprayed coating, Ni-Cr thermally sprayed coating with surface shot peening and grinding treatment in supercritical water have been investigated at 650 degrees C under 25 MPa. The oxidation kinetics of IBN-1 steel follows the parabolic law. Compared with substrate metals, the oxidation resistance of IBN-1 steel with the three kinds of Ni-Cr coating treatment has been greatly improved due to the formation of Cr-rich oxide and the oxidation kinetics deviated from the parabolic behavior seriously. The deviation may be attributed to differences in the oxide phase with an increase in oxidation time. Furthermore, the difference in oxidation rate among different Ni-Cr coating surface treatment processes can be observed. The related mechanism has been discussed.