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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.
In the HPHT diamond-growing method that was used by Gemesis, carbon, in graphite form, was placed in a cylindrical "core". A tiny CVD seed diamond was placed at the bottom of the cylinder. The graphite was then subjected to extreme pressure, 850,000 lbf/in² (5.9 GPa) and temperature, 3,000 °F (1,650 °C) for four days.
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 .
In the past, when high pressure high temperature (HPHT) techniques were used to produce a diamond, the result was typically very small free-standing diamonds of varying sizes. With CVD diamond, growth areas of greater than fifteen centimeters (six inches) in diameter have been achieved, and much larger areas are likely to be successfully coated ...
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]
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.
Synthetic diamonds, also referred to as lab-grown diamonds, are created using advanced technological processes such as High-Pressure High-Temperature (HPHT) and Chemical Vapor Deposition (CVD). These methods result in diamonds that are chemically and physically identical to natural diamonds , offering the same brilliance and durability.