Cermet coatings produced by vacuum-arc evaporation of a high-entropy alloy

Abstract

Multilayer metal-ceramic coatings based on a high-entropy alloy of elemental composition TiNbZrTaHf were formed by deposition onto a solid substrate in vacuum from a multicomponent gas-metal plasma created by vacuum-arc evaporation of a multi-element cathode in a plasma-assisted mode in a nitrogen-argon gas mixture. It was shown that the coatings are a nanocrystalline (2.5–4 nm) material. X-ray phase analysis showed that the ceramic layer was biphasic (TiNbZrTaHf)N + Ta4N). The nitride (TiNbZrTaHf)N has a face-centered crystal lattice with lattice parameter of a = 4,4465 Å (D = 22 nm; Δd/d = 7·10–3). The nitride Ta4N has a tetragonal crystal lattice with lattice parameters of a = 6.8272 Å, c = 4.1697 Å (D = 10 nm; Δd/d = 7·10–3). The metal layer has a body-centered cubic crystal lattice (a = 0.33396 nm). The formation of transition layers between the substrate and the metal layer and between the metal and ceramic layers was revealed. The hardness of the coating was 36.7 GPa, Young’s modulus was 323 GPa, coating wear parameter k = 2.9·10–5 mm3/N·m, friction coefficient μ = 0.71. In the future, the use of HEAs-based coatings as protective coatings for tools and parts of a wide range of applications will be promising.