Effect of Diamond Abrasive Processing Conditions on the Structure of the Damaged Layer of a Diamond Single Crystal

The structure of the near-surface damaged layer in diamond single crystals after circular grinding is studied using scanning and atomic force microscopy. It is shown that the dimensions and structure of the damaged layer are determined by the fractional composition of diamond grains in the diamond abrasive tool. The structure of the damaged layer of the single crystal is formed by networks of microcracks with open and closed crack mouths dividing the layer into blocks. The near-surface section of the damaged layer consists of blocks (1–3 μm) separated by a network of microcracks. Further on, there is a section of larger blocks, which transitions into a section of blocks located between fragments of the damaged grains of the single crystal. Wear of a diamond single crystal during diamond abrasive grinding occurs as a result of two simultaneously occurring processes: formation of a damaged surface layer during dynamic contact interaction of diamond grain tips on the single crystal surface and its destruction during the penetration and movement of diamond grain tips in the damaged layer. Contact interactions of diamond grain tips with the single crystal surface determine its morphology, the structure of the damaged layer, which affect the color characteristics of the diamond.