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 ≈ 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.