Description:
<p>The coefficient of friction of surfaces lubricated under boundary conditions may be profoundly affected by such factors as the degree of working of the substrate material, the nature of the oxide film and the degree of roughness of the surface. Experiments are described wherein the frictional behaviour of surfaces of stainless steel specimens prepared in various ways was compared. The worked surface layers in these particular experiments appear to increase the value of the coefficient of friction, but the effect of surface texture is of predominant importance. The effect of different oxide films is best illustrated by reference to pure aluminium, the surface of which has been oxidized under different environmental conditions. The constitution of the oxide film formed is modified with a consequent effect on boundary friction. When the friction of rough and smooth surfaces is compared, the difference in behaviour appears to be qualitative rather than quantitative.</p>