Effect of Target Voltage on Tribological and Adhesive Properties of c-BN Films Coated with HiPIMS

Although c-BN film has many advantages, it is known that the biggest disadvantage of c-BN films is adhesion. Various methods are used to improve the adhesion properties of c-BN films. One of them is to deposit c-BN films with HiPIMS (High Power Impulse Magnetron Sputtering) technique. HiPIMS gives superior properties to films according to dc and pulsed-dc magnetron sputtering techniques. In this study, c-BN films were coated on 4140 steels with HiPIMS-CFUBMS (Closed Field Unbalanced Magnetron Sputtering) hybrid system under different target voltage. In the system, HiPIMS applied to two B4C targets and pulsed-dc applied to TiB2 and Ti targets. The film thicknesses and wear tracks were investigated using SEM. The composition was analyzed using XPS and FT-IR. The mechanical properties were obtained with microhardness tester and scratch tester. The tribological properties were carried out using pin-on-disc. The measured hardness values varied between 43GPa and 56GPa. The highest critical load (Lc approximate to 33N) was obtained from the coating with the lowest compressive internal stress (6.02GPa). Friction coefficient values were obtained between 0.126 and 0.166. The results showed that HiPIMS technique gave superior properties.