Features of (ZrHf)N coatings deposited using a Zr-Hf cathode under different parameters of the deposition process

Abstract

This article considers the properties of (Zr,Hf)N coatings deposited on a titanium alloy substrate at different arc currents (70, 90, and 110 A) and bias voltages (–80 and –150 V). Transmission electron microscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray microanalysis, pin-on-disk wear testing, scratch-testing and electrochemical corrosion tests were used as investigation techniques. It was found that changing the deposition process parameters (arc current and bias voltage) in the considered ranges does not affect the ratio of the element content in the coating composition. The main phase of the coating is a solid solution c-(Zr,Hf)N (B1), characterized by the presence of compressive stresses. When the cathode arc current changes from 70 to 110 A, a decrease in the grain size is observed. The minimum grain sizes are observed in the coating deposited at a bias voltage of –150 V and an arc current of 110 A. Arc current in the used values range affects more strongly on coating thickness than voltage bias. The coating deposited at an arc current of 70 A peels off from the substrate in the pin-on-disk test; as a result, the wear resistance of this coating is lower compared with the coatings deposited at an arc current of 90 and 110 A, which do not peel off from the substrate. Changing the deposition parameters does not significantly affect the critical force corresponding to complete peeling of the coating in tests for adhesion strength and electrochemical corrosion resistance of coatings in a 3% NaCl environment at room temperature.