Synthetic diamond

Artificially non-diamond carbon structure into a diamond structure carbon , and are formed by nucleation and growth of monocrystalline and polycrystalline diamond, or the fine-grained diamond sintered polycrystalline diamond at high pressure and temperature . An important example of this is the high pressure applied in the current research on the production .
From the viewpoint of thermodynamics , the decision diamond structure of graphite and other non- carbonaceous material into a diamond can Phase Transition of the latter must be less than the free energy mold for grinding wheel of the former . This phase transition under conditions of high pressure , high temperature or other components participating conducted . Certain pressure , temperature and component concentration can make the system can change, so that the valence electrons can be right at the statistical level of weight change accordingly . This electron transfer , and may be bonded to form a new state of the electronic structure, i.e., the phase transition occurred . If the energy change in favor of the occurrence of this change in the electronic structure of the solid , the pressure and temperature in the solid state phase transition occurs , or may occur in the molten or vapor state . This change steel fiber for concrete reinforcement of condition occurs in the melt , the statistical characteristics of the right bonding valence electron distribution corresponding decrease weight , the effect tends to disappear remote ordered atomic coordination number changes ; statistical weight and the weight of electronic excited state chemotaxis at increasing the role of short-range order corresponding enhancement. This condition occurs in the gas change is elemental electron energy level bonding between atoms or molecules of the compound tends to disappear and all the electrons are transferred to a single atom or molecule level up , so that the electron is re- excited state statistical weight more is increased. Thus, the synthetic diamond may be in a solid state , but also in the melt state and the vapor state conditions , depending on pressure, temperature and component concentration changes can be caused by factors within the system . From the kinetic point of view, but also requires a change in the rate of change in the appropriate carbonaceous materials such as graphite into diamond when . Phase change rate of the diamond nucleation rate and growth rate at the same time when the maximum value is the maximum .