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. To address this issue, silicon (Si) doped DLC films with Si content ranging from 0 to 11.52 at.% were synthesized utilizing the plasma‐assisted reactive magnetron sputtering technique. The influence of Si incorporation on the microstructure and mechanical properties was meticulously investigated by Raman spectroscopy, scanning electron microscope (SEM), X‐ray photoelectron spectroscopy (XPS), nanoindentation, and scratch testing. To ascertain the tribological behavior of the Si‐DLC films under elevated temperature conditions, in situ high‐temperature tests were conducted, spanning temperatures from ambient to 500°C. The findings indicated that distinct lubrication mechanisms prevail for Si‐DLC films with varying Si content across different temperature domains. As the test temperature and Si content increased, the lubrication mechanism exhibited a gradual transitions from high‐temperature induced graphitization to a particle wear regime dominated by SiC and formed SiO2 abrasive phases. The comprehensive performance of the films peaked at a Si content of 4.72 at.%, suggesting an optimal composition for high‐temperature applications. It is postulated that the in‐depth investigation presented herein holds considerable value for the design and fabrication of DLC films intended for use in high‐temperature settings, potentially unlocking their full potential in such demanding environments.