Wear-Resistance of High-Entropy Alloy Coatings and High-Entropy Alloy-Based Composite Coatings Prepared by the Laser Cladding Technology: A Review

With the continuous development of the aviation and aerospace industries, there is an increasing demand for surface coatings that can enhance the wear-resistance and lubricity of substrates. High-entropy alloy (HEA) coatings and high-entropy alloy-based composite coatings (including ceramic and lubricating phases) have attracted large attention, which is due to their excellent properties. They have, therefore, developed rapidly in the past decade. This article reviews the current status of research on the tribological properties of the HEA coatings and HEA-based composite coatings that have been prepared by laser cladding technology. The focus is then on the wear-resistance and wear-reduction mechanism of the coatings. Furthermore, the review analyzes the influence of element addition, atomic ratio change, and process parameters on the coating organization and properties. The problems that have to be solved in the development of tribology-based HEAs coatings, and the expected future development of HEA the coatings, are also discussed.