Development of diamond

18th century, it was discovered that the noble diamond turned out to be worth a carbon allotrope, since then, has become a preparation of synthetic diamond glory and the dream of many  cubic boron nitride  A century later, graphite - Another elemental carbon form was discovered, people will try to simulate natural processes, so that the graphite in the ultra-high temperature and pressure environment into a diamond. In order to shorten the reaction time, the need 2000 ℃ temperature and 55,000 atmospheres special conditions.
In 1955, the U.S. General Electric Company specializes in the manufacture of high temperature and pressure  cutting tools , to get the world's first synthetic diamond for industrial use small crystals, thus creating industrial-scale production of synthetic diamond abrasive precedent, now that their annual production of 20 tons; Soon, DuPont invented the explosion method, the use of instantaneous explosion of high pressure and rapid warming, also received a few millimeters in size synthetic diamond.
The properties of diamond films on diamond particles less, the density and hardness to be lower. Even so, it is also one of the best wear resistance, only 5 microns thick film, life expectancy is 10 times longer than carbide steel above. We know that the album in a tiny needle contact surface is subjected to great pressure, while requiring extremely long wear life, as long as the tip of diamond film deposited on a layer, it can be easy to battle it. If the plastic, glass, diamond films made outside with wear-resistant coating, which can greatly extend their use, development of superior performance and economical products.
More importantly, the film appears to make the application of stone broke through the barriers only as a cutting tool, making it excellent thermal, electrical, acoustic, optical properties can be fully tapped. Currently, the diamond film has been applied in semiconductor electronic devices, optical acoustic devices, pressure processing and cutting tools and other aspects of its development at an alarming rate in the high-tech sector more attractive.
Artificial way of non-diamond carbon structure into a diamond structure carbon, and by the formation of crystal nucleation and growth and polycrystalline diamond, or the fine particles at high pressures and temperatures of diamond sintered polycrystalline diamond. Pressure Study is currently applied in the production of an important example.
Since the 18th century confirmed the diamond is composed of pure carbon future, they began the study of synthetic diamond, but in the 1950s by high-pressure and high-pressure research progress in experimental techniques, only a true success and rapid development. The specific method of synthetic diamond currently up to a dozen. According to the characteristics of the technology used can be summarized as static, dynamic pressure and low pressure three methods. Characterized by the formation of diamond can be summarized as directly, melting and other categories of media and outreach methods. Diagram shows the pressure of carbon - Temperature (□ - □) phase diagram and three methods of synthetic diamond experimental area. Diamond and graphite are allotrope, their chemically identical, are composed of carbon atoms, but  Diamond blade  properties, simply put, is a soft, one hard.
    Reason for this difference is that they are different forms of atomic crystalline graphite crystal structure is layered, the smaller the force between layers, the lower the force between the external force can easily be destroyed, that is, we say The relatively soft. The three-dimensional crystal structure of diamond, each atom and its neighboring atoms have the same large force, and large, extremely large external force required lower intermolecular forces in order to be destroyed, that is, we say particularly hard.
    We usually call it a natural diamond diamonds, natural variations in the long term (eg strong crustal changes), the carbon atom subjected to high temperatures, high pressure forming, synthetic diamond is also manufactured according to this principle: the graphite straight in a special container first heated to a high temperature (2 000 ℃ above), and then suddenly cause a momentary force is applied tremendous pressure (greater than 55 000 atm), after opening the container can be found in graphite diamond grains. These are the main manufacturing process of synthetic diamond. Zone 1 is the direct method of synthetic diamond experiments Zone 2 as synthetic diamond melting experiments media law area, three areas of synthetic diamond epitaxy experimental area.