Commercial sparkle of man-made diamonds
June 5, 2018 -- Man-made diamonds -- manufactured by chemical vapour deposition (CVD) -- are grown in carbon-containing gas in a plasma state. Layers of carbon atoms create stones chemically identical to mined diamonds.
The first synthetic diamonds were made in Sweden in 1953 by a high pressure-high temperature process, literally a carbon-copy of nature.
In 1989, a technological leap was achieved when the Diamond Research Laboratory (DRL), later to become De Beers’ Element Six, completed diamond synthesis using a low-pressure CVD.
A diamond is one giant molecule of carbon atoms. Using CVD, diamond forms in a high-temperature plasma mix of hydrogen and methane, at very low pressures inside a vacuum chamber. An actual diamond crystal acts as a seed for diamond growth.
A fundamental problem of diamond synthesis is the allotropic nature of carbon itself. Different physical forms of the element include diamond, graphite and buckminsterfullerene or “buckyballs” -- graphite, not diamond, is the stable crystalline phase of carbon.
DRL’s breakthrough was the discovery of optimal gas mixtures and temperatures for diamond growth. By using a high supersaturation of atomic hydrogen, carbon atoms form three dimensional tetrahedral bonds of diamond as opposed to weaker bonds of graphite.
Apart from jewellery, synthetic diamond has commercial applications from oil and gas drilling to cutting-edge electronics. Synthetic diamond is a candidate material for quantum computing which performs operations that are not possible using computers that follow classical physics.