Molecular dynamics study of the frictional behaviors of diamond-like carbon films

P Wei and MY He and WB Ao, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 127, 652 (2021).

DOI: 10.1007/s00339-021-04814-0

The frictional behavior between self-mated diamond-like carbon (DLC) films is investigated systematically by molecular dynamics (MD) simulation, analyzing the role of atomic configuration evolution in the sliding process and focusing on the intrinsic causes of different frictional behaviors. According to the different sliding speeds, there are two ways of friction evolution: sawtooth-type stick-slip friction and smooth friction. The results show that the evolution of atomic configuration plays an important role in the variation of friction force. The periodic shear deformation and interface fracture evolution mode exhibited by the system controls the friction variation at low velocities, leading to sawtooth-type stick-slip frictional behavior. However, in the process of high-speed sliding, the stable sliding interface leads to the stable number of C-C covalent bonds at the interface, which makes the system show smooth friction behavior. At this time, the friction is mainly controlled by the interfacial C-C bonds and is influenced by the graphitization phase transition. The research work in this paper can deepen the understanding of the internal mechanism of frictional behavior of diamond-like carbon films.

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