Effect of Ni Content on the Microstructure, Performance, and Mechanical Properties of High-Entropy Alloy Nitride (AlCrTiMoVNi)N Coatings Produced by Cathodic Arc Evaporation

High-entropy (AlCrTiMoVNi)N coatings were prepared using cathodic arc evaporation. The target composition was varied to investigate the effect of nickel concentration from 0 to 8 at.% of target composition on the microstructure, mechanical properties and tribological performance of the coatings. The nitride of all coatings assume a B1 face centered cubic structure. The various coatings contain many small droplet and large splat defects, and the amounts of those defects increase with the concentration of Ni. All coatings showed excellent high-temperature phase stability. The hardness and elastic modulus reached maximum values 2% Ni and then, decreased as the Ni content increases. In terms of performance, the coating with 2% Ni had the lowest wear rate while in erosion testing the coating free of Ni had the lowest erosion rates. Overall, the presence of droplets/splats had a significant influence on the tribological performance of the coating.