Microscopic aspects of friction

In this work we first present an analysis of the interaction energy and short range forces between two parallel and atomically flat metal slabs. Using the self-consistent field pseudopotential method within the local density approximation we obtain the interaction energy surface and lateral force variation for two parallel metal slabs in relative motion under a constant loading force. Based on these results we investigate the stick-slip motion in the dry sliding friction. The effects of material parameters and loading force on the friction force are analyzed by using an infinite chain of atoms having two degrees of freedom in the lateral and normal directions. The foreign atoms between two sliding surfaces prevent them from strong adhesive contact and wear. This is the boundary lubrication and takes place under the low coverage of inert gas atoms (Θ < 1). In order to reveal the essential features of stick-slip motion of the lubricant atoms and the energy damping thereof, we finally studied the motion of Xe atom on the metal surface manipulated by a metal tip.