Development and Characterization of High-Entropy Alloy Coatings for Enhanced Wear and Oxidation Resistance in High-Temperature Applications

Abstract

High-temperature engineering components operating in aerospace gas turbines, thermal power plants, petrochemical reactors, automotive engines, nuclear systems, and advanced manufacturing equipment are continuously exposed to severe operating conditions involving elevated temperatures, oxidation, abrasion, erosion, corrosion, thermal cycling, and mechanical loading. Conventional protective coatings such as nickel-based superalloys, chromium coatings, ceramic thermal barrier coatings, and hard carbide coatings provide satisfactory performance under moderate operating conditions but often suffer from oxidation-induced degradation, thermal fatigue, microcracking, elemental diffusion, phase instability, coating delamination, and accelerated wear during prolonged exposure to extreme environments above 800–1000°C. These degradation mechanisms significantly reduce component reliability, service life, and operational efficiency while increasing maintenance costs and unscheduled downtime. Consequently, the development of advanced coating materials possessing exceptional thermal stability, oxidation resistance, wear resistance, and mechanical durability has become an important research objective in modern materials engineering. This paper presents the Development and Characterization of High-Entropy Alloy Coatings for Enhanced Wear and Oxidation Resistance in High-Temperature Applications. The proposed investigation employs laser cladding to fabricate CoCrFeNiAl-based High-Entropy Alloy coatings on nickel-based superalloy substrates. Detailed characterization includes scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), electron backscatter diffraction (EBSD), microhardness testing, high-temperature oxidation experiments, pin-ondisc tribological evaluation, and thermal cycling analysis. The relationships among coating microstructure, phase evolution, hardness, oxidation kinetics, wear mechanisms, and thermal stability are systematically investigated. Experimental results demonstrate that the developed HEA coatings exhibit significantly improved microhardness, oxidation resistance, wear resistance, phase stability, and coating integrity compared with conventional protective coatings, making them highly suitable for advanced hightemperature engineering applications.