The Influence of Nitrogen Partial Pressure on the Microstructure and Mechanical Properties of HfNbTaTiVZr High-Entropy Nitride Coating Deposited via Direct Current Cathodic Vacuum Arc Deposition

In recent years, high-entropy alloys have attracted increasing scientific interest. Due to their promising combination of properties, such as high hardness and high temperature stability, they are attractive for use as tool coatings for machining applications, to give but one example. Previous studies often focused on layer deposition using magnetron sputtering. Comparatively little research has been carried out to date on coating deposition using direct current cathodic vacuum arc deposition (CAE), with higher achievable rates and almost completely ionized plasmas. The aim of this work is to investigate (HfNbTaTiZr)N-coatings produced by CAE. The nitrogen content was varied and the effects on the coating properties were investigated. Changing the N2/(N2 + Ar) ratio between 0.1 and 1.0 and varying the working pressure in the chamber from 2 Pa to 5 Pa resulted in variations of the nitrogen content of the coatings, ranging from 30 at% to 50 at%. Although different microstructures of the coatings were obtained, there was only a minor influence on the hardness and Young’s modulus.