The direct method of artificial diamond uses transient static ultra-high pressure and high temperature technology, or dynamic ultra-high pressure and high temperature technology, or a combination of the two technologies to directly convert carbonaceous raw materials such as graphite from solid or molten state into diamond. The diamond obtained by this method is Micron-sized polycrystalline powder. The flux method synthetic diamond uses static ultra-high pressure (50-100kb, that is, 5-10GPa) and high temperature (1100-3000°C) technology to generate diamond through the reaction of carbonaceous raw materials such as graphite and certain metals (alloys). Its typical crystal state For the cube (hexahedron), octahedron and hexa-octahedron and their transitional forms. The main application value that shows important application value in industry is the static pressure flux method. The output of abrasive-grade synthetic diamonds obtained by this method has exceeded that of natural diamonds. The problems to be further solved are to increase the coarse-grain ratio, increase the conversion rate and improve the crystal quality. At present, the formation of high-quality large-grain single crystal diamond is being studied in the laboratory using static pressure flux method. The seeded epitaxial growth method used to obtain large single crystals weighing about 1 carat; after a slight improvement with general experimental techniques, crystals of about 2 to 4 millimeters were obtained. Using this method also grows and sinters large particles of polycrystalline diamond. The latter has been used in industry. The key issue is to further improve the compressive strength, impact strength, wear resistance and resistance of this polycrystalline diamond. Comprehensive performance such as heat resistance. Epitaxial method Synthetic diamond is epitaxially grown on diamond seed crystals or some materials that act as substrates by using carbon sources precipitated during pyrolysis and electrolysis of certain carbonaceous materials. Wurtz reaction method allows carbon tetrachloride and sodium to react at 700°C to produce diamond. However, a large amount of graphite is generated at the same time. The formation mechanism mainly includes the following theories: solvent theory believes that the metal (alloy) used acts as a solvent for carbon; catalysis theory believes that it is a catalyst; solid phase transition theory emphasizes that graphite crystals do not need to break bonds and disintegrate, and undergo simple deformation. Then diamond crystals are formed. However, the models proposed by these three typical theories often contradict some major experimental phenomena and laws. Therefore, theories such as solvent-catalyst, catalyst-solvent, melting (solvent) agent-catalyst (referred to as flux) have emerged to further explore the role of the metal (alloy) used. In general, the formation mechanism of synthetic diamond is still a complex issue still under discussion. The related thermodynamics is published in "Inorganic Chemistry" (fourth edition, page 236, line 9 from the left, and the 16th word from the left). It clearly mentions: According to investigations, the conversion of graphite to diamond under high pressure is exothermic! Low temperature On the contrary, it is conducive to conversion.