Tailoring the Mechanical and High-Temperature Tribological Properties of Si-Dlc Films by Controlling the Si Content

The poor high-temperature tribological performance of diamond-like carbon (DLC) films severely limits their applications. The Si doped DLC films with Si content varied from 0 to 11.52 at.% are deposited by plasma-assisted reactive magnetron sputtering method. The effect of Si on film structure and mechanical properties are investigated by Raman, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), nano-indentation, scratch techniques. The in-situ high-temperature test from room temperature to 500 °C are performed to evaluate the tribological properties of the Si-DLC films. The results show that different lubrication mechanisms exist for Si-DLC films with different Si content at different temperatures. As the test temperature and Si content increase, the lubrication mechanism of the film gradually transitions from high-temperature induced graphitization to a particle wear mechanism dominated by SiC and fomed SiO2 abrasive phases. The overall performance of the films reaches its optimum at a Si content of 4.72 at.%.