Effect of carbon diffusion on friction and wear properties of diamond-like carbon in boundary base oil lubrication

In order to control wear and friction in industry, Diamond like carbon (DLC) hard coatings are widely applied in recent years due to their well appreciated mechanical and tribological properties. However, those properties are not yet well understood, as well as behavior of DLC hard coatings when rubbed against other materials. Other researchers reported that DLC hard coatings film show high wear when rubbed against steel counterpart and their durability decrease with the increase of the temperature. In this research, we investigated on friction and wear properties of DLC coatings and the results reveal that carbon diffusion has a key role in the wear and friction behavior of DLC coatings when rubbed against steel. •Evidences of carbon diffusion from DLC film into steel disk was founded.•Increase of the content in iron carbide Fe3C was observed after experiment.•A wear mechanism of DLC film when rubbed against steel disk is proposed.•Smooth surface provided low friction coefficient.