Effects of substrate bias voltage on mechanical properties and tribological behaviors of RF sputtered multilayer TiN/CrAlN films

Abstract

Multilayer brittle TiN/CrAlN films were prepared on polished silicon and high speed steel by RF magnetron sputtering technology with various substrate bias voltages ranging from 0 to −150 V. In this study, the main attention is targeting the correlation between the substrate bias voltage and the resulting mechanical–tribological properties. It is revealed that the films become much denser and more compact with increasing substrate bias, meanwhile, hardness and elastic modulus are correspondingly elevated. However, relatively decreased adhesion emerges when reaching the bias voltage of −150 V. The wear resistance is progressively enhanced while the deposition rate gradually declines as the substrate bias increases. Additionally, the mean values of dry friction coefficients sliding against Si3N4 are in the range of 0.57–0.42, and the wear volumes are ranging from 23.97 × 10−3 to 13.93 × 10−3mm3. Thus, it can be drawn that the film maintains more excellent mechanical and tribological properties, which is sputtered at the moderate substrate bias of −100 V.