Relation between friction and hardness

Abstract

Although hardness has little effect on friction there is evidence that in general the friction is less with harder metals. Experiments on a carefully selected series of copper beryllium alloys show that the friction decreases linearly with the hardness. For a given load the amount of plastic deformation at the points of intimate contact is greater for a soft metal. It is suggested that this deformation facilitates disruption of the oxide film so that for softer metals the proportion of oxide-free junctions is greater. The resulting frictional force is therefore higher.