Ab initio Molecular Dynamics Simulation of Water Tribochemistry at Si-doped Diamond-like Carbon Surfaces

摘要

To unravel the atomistic mechanisms for the low friction of Si-doped diamond-like carbon, we carry out ab initio molecular dynamics simulations of tribochemistry. In particular, we simulate the chemical reactions involving water molecules confined at a Si-doped diamond interface under tribological conditions (shear and load). We found that Si doping increases the probability of water dissociation, which results in an increase of OH surface termination. This enhancement of the chemical reactivity may account for the low friction property, because it is expected that the surface hydroxylation favors the formation of a water boundary layer that prevents the direct contact of the sliding surfaces.