A study of strains in abraded diamond surfaces

Abstract

The nature of surface damage suffered by diamond during abrasion processes has been studied by X-ray topographic analysis of the strain patterns in and around microabrasion patches on cube, dodecahedron and octahedron surfaces of highly perfect natural diamonds. The strain field has been computed from an elastic model assuming that the abrasion leaves a thin surface layer of crystal in a state of residual compression. The observed diffraction contrast agrees well with this model. From the contrast patterns the stresses in the surface, expressed as force in the surface acting normally to unit length in the surface, lie in the range 1 × 10 5 to 5 × 10 5 dyn/cm, with little dependence upon orientation of the abrasion. The evidence strongly favours a microcracking mechanism for abrasive wear of diamond.