Control and Minimization of Friction via Surface Modification

Abstract

Friction between surfaces is a function of the additive effects of load and the true area of contact, but factors such as surface roughness, interfacial energies, and material elastic properties can influence the relative importance of "load controlled" and "adhesion controlled" friction. We consider the applicability and limitations of Amontons' law, F= mu L, and the less common but more favorable conditions where the area of contact rather than the load dominates the friction force at high loads. The theoretical basis for load and area dependent friction are examined in the context of molecular mechanisms involved in friction, and simple theoretical predictions are compared with experimental results on a variety of smooth and rough surfaces, both lubricated and unlubricated.