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The advantages of CVD diamond growth include the ability to grow diamond over large areas and on various substrates, and the fine control over the chemical impurities and thus properties of the diamond produced. Unlike HPHT, CVD process does not require high pressures, as the growth typically occurs at pressures under 27 kPa (3.9 psi). [51] [60]
InCent-LGD has three core research groups dedicated to different aspects of lab-grown diamond technology: [5] High Pressure High Temperature (HPHT) Group: This group focuses on the HPHT method of diamond growth, which simulates the natural diamond formation process by subjecting carbon to high pressure and high temperature.
Synthetic diamonds are produced via high pressure, high temperature or chemical vapor deposition (CVD) technology. These diamonds have numerous industrial and commercial uses including cutting tools, thermal conductors and consumer diamond gemstones.
CVD growth allows one to control the properties of the diamond produced. In the area of diamond growth, the word "diamond" is used as a description of any material primarily made up of sp3-bonded carbon, and there are many different types of diamond included in this. By regulating the processing parameters—especially the gases introduced, but ...
Gemesis Inc. was a privately held company located in New York City.The company grew synthetic diamonds using proprietary technology.. Gemesis had the world's largest facilities for both the high-pressure high-temperature (HPHT) and chemical vapor deposition (CVD) diamond production methods.
Diamonds treated to become colorless are all Type IIa and owe their marring color to structural defects that arose during crystal growth, known as plastic deformations, rather than to interstitial nitrogen impurities as is the case in most diamonds with brown color. HPHT treatment is believed to repair these deformations, and thus whiten the stone.
The hardness of synthetic diamond (70–150 GPa) is very dependent on the relative purity of the crystal itself. The more perfect the crystal structure, the harder the diamond becomes. It has been reported that HPHT single crystals and nanocrystalline diamond aggregates (aggregated diamond nanorods) can be harder than natural diamond. [25]
"Ultrahard fullerite" is a coined term frequently used to describe material produced by high-pressure high-temperature (HPHT) processing of fullerite. Such treatment converts fullerite into a nanocrystalline form of diamond which has been reported to exhibit remarkable mechanical properties. [63] Fullerite (scanning electron microscope image)