New trends in high-pressure synthesis of diamond

Four stages are distinguished in high-pressure synthesis of diamond. The first is design features providing for the optimal distribution of pressure and temperature in the reaction cell volume. Computer-aided modelling of a multielement medium by numerical calculations based on non-linear mechanics of elasto-plastic deformation is used. The second involves the definition of p,T conditions of diamond crystallization on the strength of Me-carbon phase diagrams under pressure. The third relates to the formulation of metal-carbon reaction compositions based on the contact interaction of carbon phases under pressure. The fourth consists of a high-pressure-high-temperature treatment of diamond crystals with the aim of changing their impurity and defect states. (C) 1999 Elsevier Science S.A. All rights reserved.