Cathodic arc deposition of NiCrAlY coating: oxidation behaviour and thermodynamic

NiCrAlY coating was deposited on the Ni-base superalloy in the cathodic arc deposition process. The isothermal oxidation test was carried out at 1000 degrees C in air. The cross-section of the coatings was studied by the field emission scanning microscope electron and energy dispersive spectroscopy. The formation and growth of the internal oxide were addressed during the high temperature oxidation. The outward diffusion of Ti occurred from the substrate to the coating, leading to the formation of TiO2 beneath the thermally-grown oxide scale. Thermodynamic measurements of TiO2 formation were performed and the role of the internal oxide in the formation of TiO2 was determined.