Cyclic Oxidation Properties of the Nanocrystalline AlCrFeCoNi High-Entropy Alloy Coatings Applied by the Atmospheric Plasma Spraying Technique

Microcrystalline and nanocrystalline AlCrFeCoNi high-entropy alloy (HEA) coatings were applied on Inconel 718 superalloy using the atmospheric plasma spraying (APS) process. The high-temperature oxidation behavior of microcrystalline HEA-coated was examined at 1100 °C under air atmosphere for 50 cycles cyclic heating cooling (1 h each cycle). kinetics both nanocrystalline- microcrystalline-coated superalloys accordingly analyzed by weight change measurements. We noted that uncoated coated samples followed parabolic rate law oxidation. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive analysis (EDS), elemental mapping photoelectron spectroscopy (XPS) used to analyze oxidized samples. In superalloy, Fe, Ni, Co Al in inter-splat region, whereas splats, which consisted mainly Ni Cr, remained unoxidized. Due formation compact adhesive thin NiO, CoO oxides spinels together with Al2O3 oxide scale surface coating during oxidation, developed HEA showed better resistance compared coating.