Effect of Increasing Duty Time and Target Voltage on Adhesion and Tribological Properties of B4C Films Coated with HiPIMS at Constant Nitrogen Flow

The mechanical, tribological, and chemical characteristics of nitride-based coatings make them crucial for industrial applications. C-BN films have better qualities than other nitride-based films. However, when ultra-high hardness values have been achieved, the adhesion characteristics of c-BN films produced by magnetic field sputtering with various power sources are often inadequate. High Power Impulse Magnetic Field Sputtering (HiPIMS) power sources have been applied recently to improve coating adhesion. In this study, c-BN films were coated on 4140 steels at increasing duty time and target voltage at constant N2 flow using HiPIMS technique. SEM and FT-IR analyses were performed to investigate the structural properties of c-BN films; microhardness and scratch tests were performed to investigate their mechanical properties; pin-on-disk tribo test was performed to determine their tribological properties. As a result of the tests, the film thickness increased with increasing duty time and target voltage, while the hardness value and critical load value decreased. In addition, friction coefficient decreased with increasing duty time and target voltage.