Structural and tribological properties of TiC-DLC coatings deposited by RCAE-PVD at various bias voltages

The aim of the current study was the evaluation of the bias voltage influence on the structural and tribological properties of titanium carbide dispersed in diamond-like carbon (TiC-DLC) coatings. To this end, TiC-DLC was deposited on 440C stainless steel substrate by physical vapour deposition method with titanium target and acetylene gas sources. The coating process was performed at the constant chamber pressure of 5 mbar and the bias voltage in the range of 100 to 400 V. The coatings were characterised by means of field emission SEM, X-ray diffraction and Raman spectroscopy. Pin on disc test was used for studying the wear behaviour of the coatings. The best tribological properties of coatings were reached at the bias voltage of 200 V. Overall, raising the bias voltage up to 200 V led to the decrease in the wear and friction initially, while getting the higher voltage (up to 400 V) reversed the process.