Effects of power on tribological and mechanical properties of diamond-like carbon-film-modified rubber

Abstract

This study aims to improve the wear resistance of nitrile butadiene rubber (NBR) by depositing diamond-like carbon (DLC) films using direct-current magnetron sputtering (DC-MS), a simple and cost-effective technique. DC-MS is a coating process that uses a direct current to generate an electric field and sputter conductive materials from a target to a substrate. A magnetic field enhances the plasma density and sputtering rate. This study examines the bonding force, surface morphology, tribological properties and mechanical strength of DLC. Scanning electron microscopy, Raman spectroscopy and X-ray photoelectron spectroscopy are used to characterize the cross-sectional morphology, structural features and chemical bonding species of DLC films and NBR substrates. The nanoindentation results show that varying the power has no significant effect on hardness and Young’s modulus. Tribological tests are conducted under ambient conditions using a ball-and-disk tribometer, with a fixed load of 0.3 N. The results indicate that the power of DLC films influences their tribological properties. Specifically, DLC films prepared at 120 W exhibit superior tribological properties, maintaining a stable coefficient of friction below 0.2 for the test duration. These findings have promising implications for application of DLC films.