Frictional behaviour of thin films of soft metals

Abstract

The role of thin soft metallic films in reducing the friction between metal surfaces is discussed. An empirical relationship is proposed to explain the phenomenon of decreasing friction with decreasing film thickness for thin films of soft metals in spherical contact. The friction coefficient varies with the cube root of the film thickness/load ratio. This formula is applicable where there is a deviation from Amonton's law. The deviation from Amonton's law is explained on the basis of substrate participation with plastic deformation. Agreement is obtained between the theory and experimental data of Rabinowicz, and Bowden and Tabor for electrodeposited films.