Coarse-Grained Molecular Dynamics Simulations of Boundary Lubrication on Nanostructured Metal Surfaces

Abstract

Coarse-grained molecular dynamics simulations were carried out to investigate the frictional properties of lubricant molecules on nanostructured metal surfaces. The simulation cell consists of a lubricant film enclosed between two metal surfaces. The attractive potential of specific iron atoms on the surface was modified such that the lubricant molecule adsorb preferentially on these atoms. These particular iron atoms were arranged to reproduce a grain boundary surface nanostructure. It is found that below the critical normal stress, the strength of the interaction between Fe and the lubricant molecule has little effect on the friction coefficient. However, the behavior of the lubricant film on the metal surface is sensitive to the interaction strength. Large attraction forces increase the adherence of the lubricant film.