Synthetic diamond manufacturing method

Direct method
Artificial diamond or high pressure high temperature technology using instantaneous static or dynamic high pressure high temperature techniques, or a mixture of both techniques , carbonaceous materials such as graphite, to make changes directly from a solid or molten state to the diamond, diamond obtained by this method are micron size polycrystalline powder.
Melting media law
Static high pressure synthetic diamond (50 ~ 100kb, i.e., 5 ~ 10GPa) and high temperature (1100 ~ 3000 ° C) by techniques synthetic diamond such as graphite, diamond produced by the reaction of carbonaceous materials and certain metals ( alloys ) , which is typically a crystalline cubic ( hexahedron ) , octahedron and six - octahedra and their transitional forms . Show important applications in industry is mainly static melting media law . This approach was abrasive grade synthetic diamond production has more than natural diamond , pending further problem is to increase the ratio of coarse-grained , improve the conversion rate and improve the crystal quality . Laboratory studies are currently using static media law of large particles melt quality single crystal diamond formation. Seeded epitaxial growth of large single crystals has been one karat weight around ; later improved slightly with the general testing techniques , has been crystal of about 2 to 4 mm . This method also uses a large particle growth and sintering of polycrystalline diamond, which has been obtained in certain industrial applications, the key problem is to further improve the compressive strength of polycrystalline diamond , impact strength, Fused zirconia mullite wear resistance and overall performance and heat resistance .
Epitaxy
Synthetic diamond is the use of certain hot carbonaceous material and the electrolytic solution of the carbon deposited on the seed crystal diamond substrate or from the action of certain substances formed by epitaxial growth .
Wurtz reaction
Let carbon tetrachloride and sodium at 700 ℃ reaction of diamond . But will also generate a lot of graphite.
Formation mechanism
There are several theories following : the doctrine that the solvent metal ( alloy ) plays the role of carbon in a solvent ; catalytic doctrine is considered to be a catalyst ; solid phase transition theory emphasizes the disintegration of the graphite crystal without bond breaking , formed through a simple deformation diamond crystal . But the theory put forward by the three typical models are often contradictory with some of the major experimental phenomena and laws . Therefore , there solvent - catalyst , the catalyst - solvent , melt ( solvent ) agent - catalyst ( referred to as melting media ) are used to further explore other theories metals (alloys ) role. In general , the formation mechanism of synthetic diamond is still a still exploring the complex issues .
Associated thermodynamic