Thermomechanical properties and frictional contact behavior of oxygen doped DLC film through molecular dynamics simulation

Abstract

Using the MD simulation techniques, we investigated the effects of doped oxygen atoms on the thermomechanical properties and tribological performance of diamond like carbon (DLC). The atomic percentage of oxygen (at.% O) in DLC was varied from 0 to 20.0%. The mechanical stiffness of oxidized DLC samples was evaluated using the nanoindentation simulation, while the coefficient of friction (COF) and the frictional temperature rise were obtained from the sliding contact simulation. From the simulation results, it could be found that the mechanical stiffness and the COF decreased with the at.% O in DLC. The lower COF for the oxidized DLC could be explained by the less covalent interactions with the diamond tip surface. Due to the lower stiffness, the oxidized DLC showed larger surface displacement and wear during the sliding contact. Also, the frictional temperature rise was evaluated with respect to the at.% O in DLC. The higher at.% O in DLC, the lower surface temperature rise. This could be attributed to the lower frictional heat flux and the higher specific heat of the oxidized DLC samples.