Friction tracks on diamond surfaces imaged by atomic force microscopy

The friction tracks produced by spherical diamond styli sliding on a planar diamond face along a soft direction for polishing have been imaged by atomic force microscopy. The tracks produced by a single pass as well as by multiple passes of the stylus show the presence of many individual smooth grooves, which are only a few atom layers deep. Debris formed during the sliding process was always found along the paths. The tracks produced at high loads show the presence of ring cracks as well as grooves. The morphology of the grooves indicates that wear is a process during which atoms are removed individually or in small groups. Implications for understanding the mechanism of diamond perishing are discussed. (C) 1997 Elsevier Science S.A.