Adhesion, lubrication and wear on the atomic scale

This paper reviews three important aspects of tribology (adhesion, lubrication and wear) on the atomic scale with a focus on our work on aluminum surfaces. Adhesion is critical to the success of many applications but there is no simple analytical model available to predict adhesion between different materials, so we discuss the use of electronic structure methods to investigate adhesion between Al and various ceramics to determine the factors that control adhesion. Lubricants used to control friction usually include 'boundary additives' to bind the lubricant more strongly to the surface, so that higher stresses can be employed and wear can be reduced. Little is known about how boundary additives bond to Al surfaces, so we used electronic structure methods to investigate that phenomenon. Regarding wear, we review the literature on molecular dynamics simulations to investigate nanoindentation and wear. We discuss our molecular dynamics simulations of nanoindentation and asperity-asperity shear and the effect of temperature, loading rate, interaction strength and geometry.