Influence of Diamond-Abrasive Treatment Conditions on the Structure of the Disturbed Layer of a Single Diamond Crystal

The structure of the near-surface disturbed layer in diamond single crystals after circular grinding has been studied by electron and atomic force microscopy. It is shown that the size and structure of the disturbed layer are determined by the fractional composition of diamond grains in the diamond-abrasive tool. The structure of the disturbed layer of a single crystal is formed by networks of microcracks with opened and unopened mouths dividing the layer into blocks. The near-surface area of the disturbed layer consists of blocks (1—3 microns) separated by a network of microcracks. Further there is a section of large-sized blocks, passing into a section of blocks located between fragments of broken grains of single crystal. Diamond monocrystal deterioration at diamond-abrasive grinding occurs as a result of two simultaneously occurring processes: formation of a disturbed near-surface layer at dynamic contact interaction of diamond grain tops on the surface of the monocrystal and its destruction at introduction and movement of diamond grain tops in the disturbed layer. Contact interactions of diamond grain tops with the surface of the monocrystal determine its morphology, the structure of the disturbed layer, which affect the colour characteristics of the diamond.

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