Atomistic understanding on friction behavior of amorphous carbon films induced by surface hydrogenated modification

Abstract

Friction behavior of self-mated amorphous carbon (a-C) films with hydrogenated surface were investigated by reactive molecular dynamics simulation. Results revealed that compared to the hydrogenated a-C (a-C:H) films, hydrogenating the a-C surface only improved the friction property drastically while not deteriorating the intrinsic properties of a-C films. The analysis of interfacial structure demonstrated that being different with a-C:H cases, the competitive relationship between the stress state of H atoms and interfacial passivation caused by H and C-C structural transformation accounted for the evolution of friction coefficient with surface H content. This discloses the friction mechanism of a-C with surface hydrogenated modification and provides an approach to functionalize the carbon-based films with combined tribological and mechanical properties for specific applications.