Tribological Behavior of High Entropy Alloy Coatings: A Review

Abstract

As engineering equipment is applied in a harsh environment with a heavy load, cyclic stress, and a wide range of temperatures, the reliability of the equipment becomes a challenge, especially when wear contact is involved. Hence, the design and exploitation of an advanced alloy surface may hold the key to control and minimize friction and wear in the transmission system for safety-critical applications. High entropy alloys (HEAs) or multi-component alloys have been proved to have outstanding mechanical properties, corrosion resistance, and high-temperature oxidation resistance with potential use as wear resistance and friction reduction coatings. In this paper, the properties and development status of HEAs coating systems for tribological applications were reviewed to gain a better understanding of their advantages and limitations obtained by different preparation methods. Specifically, focus was paid to magnetron sputtering, laser cladding, and thermal spraying since these three deposition methods were more widely used in wear-resistant and friction-reducing coatings. Building upon this, the correlation between composition, mechanical properties, and friction as well as wear characteristics of these coatings are summarized. Finally, the key problems to be solved to move the field forward and the future trend of tribology application for HEA coatings are outlined.

Predictive analytics of wear performance in high entropy alloy coatings through machine learning

“…The applied load and sliding velocity were recorded with the high scores and hence the highest influence in the prediction of wear rate (figure 13(a)). The applied load has a significant impact on wear rate, which influences the transition from moderate to severe deformation [88]. The sliding velocity is a critical component impacting wear rates, especially in the context of HEA coatings.…”

Effect of Cu on microstructure and properties of Co2CrFeNiMnCux high-entropy alloy coatings prepared by laser cladding

“…27 Compared to other coating preparation methods, laser cladding has the advantages of rapid cooling rate, low dilution rate, small heat-affected zone, controllable thickness and suitability for various metal powders and wires. 28,29 This technique has been applied in numerous materials to enhance the surface properties of materials such as aluminium alloys, 30 titanium alloys, 31 iron-based alloys 32 and nickel-based alloys. 33 As a result, laser cladding offers significant technological advantages in the preparation of HEACs and holds promising prospects for future applications.…”

Strategic Selection of Refractory High-Entropy Alloy Coatings for Hot-Forging Dies by Applying Decision Science

“…Die coatings can be categorized into three main groups [18,19,21]: metallic coatings (comprising transition metals, refractory metals, and lightweight metals), ceramic coatings (encompassing oxides, borides, carbides, and nitrides), and composite coatings (involving ceramic-reinforced and hybrid coatings). Upon careful evaluation, it becomes evident that refractory HEAs (RHEAs) exhibit exceptional suitability as coatings for conventional hot forge die materials, offering a remarkable combination of properties ideally suited for their intended application as coatings on hot forge dies, employing various coating techniques [19,[21][22][23][24][25][26][27].…”