Diamond, first discovered in India, is the hardest material in the world with a Mohs hardness of 10. As it has many excellent mechanical properties, it has been widely used in the field of industrial technology besides being used as ornaments. When the carbon-bearing elements in the Kimberley rocks located deep underground reach a certain concentration, they crystallize under high temperature and high pressure to form diamonds.
Based on this principle, scientists use carbon element (graphite) as raw material to artificially create high temperature and high pressure conditions for graphite, in order to obtain synthetic diamond, which has been widely used in industry. Diamond is divided into natural diamond and synthetic diamond. The transparent crystal without defects and impurities in the crystal is called gemstone grade diamond (diamond). It is mainly used for decorations, accounting for 10% - 15% of natural diamond, generally hundreds of times more expensive than gold. Diamonds with internal defects (such as inclusions, spots, cracks, etc.) or containing a small amount of other elements so that the internal crystal is free from defects but the color is not ideal for decorations belong to the industrial grade diamond, which is used to make diamond tools. High quality diamond is generally used for cutting tools. The basic properties of man-made single crystal are similar to those of natural single crystal. At present, the product quality is unstable and the cost of the same material is higher than that of natural diamond, which limits its application in cutting tools. Artificial diamond polycrystals are composed of many fine diamond grains and are commonly called polycrystals with diamond as the main component. Composite sheet is a kind of super abrasive
material which is composed of diamond polycrystals and cemented carbide. It combines the high hardness of diamond with the high strength of cemented carbide, and has the characteristics of easy welding and polycrystalline diamond. Diamond cutters (including thin film coated cutters) are mainly used in turning, milling, boring and drilling of various non-metallic and non-ferrous materials. Such as wood, glass, hard plastics, building materials, carbon fibers, ceramics, copper, aluminum matrix composites and magnesium-zinc alloys.