Effect of Nitrogen Pressure and Substrate Bias Voltage on Structure and Mechanical Properties of Vacuum Arc Deposited VN Coatings

Abstract

The binary vanadium–nitrogen (V–N) coatings were formed using cathodic arc evaporation. Two sets of coatings were produced using: (a) nitrogen pressure (pN2) from 0.001 Pa to 3 Pa at a constant substrate bias voltage (UB) of − 100 V and (b) a substrate bias voltage from − 50 to − 300 V at a constant nitrogen pressure of 1.5 Pa. The influence of the above parameters on the coating properties, in particular on the insufficiently investigated and described adhesion of the coatings to the substrate, was demonstrated. The phase transformation V → V + V2N → V + c-VN → h-VN → h-VN + c-VN and c-VN → h-VN occurs for coatings formed with increasing nitrogen pressure and substrate bias voltage, respectively. With the increase in pN2 and UB, an increase in coating hardness and adhesion to the substrate is observed, as well as an improvement in wear resistance.