Thermal oxidation behavior of ceramic-coated Ni–Cr-base superalloys

Thermal oxidation behavior of bare, Al2O3- or TiAlN-coated Hastelloy X and Inconel 617 after annealing at 1000 °C in air for 24–48 h was examined. A significant enhancement in thermal oxidation resistance was obtained from Al2O3-coated samples by either decreasing the amount of diffused Cr to the surface (Inconel 617) or preventing the diffusion of Cr (Hastelloy X). TiAlN-coated Inconel 617 also showed improved thermal oxidation resistance than bare Inconel 617, but TiAlN coating was found to have a negative effect on the thermal oxidation resistance of Hastelloy X due to its poor adhesion strength.