Abstract
Sliding friction between a copper plate and a spherical slider (copper and steel) was studied in a vacuum and air. In the case of a vacuum, specimen surfaces were made clean by means of electron bombardment. The friction of hard sliders (steel and diamond) with various radii against the (100) plane of copper was also studied in air under various loads. Although friction between similar metals is entirely due to adhesion, the main cause of fric-tion between copper and steel is by adhesion only in the case where the surfaces are extre-mely clean, since friction in air is strongly influenced by the resistance due to the bulge formed in front of the slider. Anisotropy of friction is attributable to that of the surface deformation accompanying the sliding of a slider.
