Synthetic diamond. History of appearance and method of synthesis

Attempts to synthesize diamond began at the beginning of the 19th century. Reliably confirmed experience, which ended in obtaining an artificial diamond, belongs to Henri Moissan, who in 1893 obtained the first diamonds by crystallization from a solution in a metal (iron) melt. However, the size of the resulting crystals was negligible. In the same year, independent of Moissan, an attempt to synthesize diamonds was made by the Russian geologist and chemist Konstantin Dmitrievich Khrushchev, who used silver as a melting medium. After that, numerous other attempts were made to obtain a diamond, but all of them either ended in nothing, or as a result, the smallest grains of a diamond were obtained. Subsequently, all these works were subjected to critical analysis, which denied the possibility of obtaining a diamond under the conditions of the described experiments. The first theoretical calculations of the low-temperature boundary of the diamond-graphite diagram were made in 1938 by American researchers F.D. Rossini and R.S. Jessup. And more complete thermodynamic calculations of the diamond stability field, which became the basis of the theoretical justification for the synthesis of diamond, were made by the Soviet physicist Ovsei Ilyich Leipunsky in 1939, who also suggested using a carbon solvent substance (flux) in future synthesis. Subsequently, his ideas were confirmed in successful experiments on the synthesis of diamonds in the 1950s. The first synthetic diamonds suitable for industrial applications were obtained by the Swedish electrical engineering firm ASEA in 1963, but the very fact of obtaining and producing diamonds was kept secret. The story was made public many years later in a lawsuit against a rival US firm. In the United States, successful experiments in the production of diamonds were carried out at General Electric in 1964. Russian synthetic diamonds were grown in 1958, and their industrial production began in 1961. However, all diamonds produced at that time were used for industrial needs. In 1968, the first gem-quality synthetic diamonds were produced in the USSR. Then, in the early 1970s, similar synthetic diamonds were obtained by other manufacturers. Currently, gemstones are produced by two fundamentally different technological methods - the High Pressure - High Temperature method (“HPHT”, High-pressure & High-temperature) and the Chemical Vapor Deposition (“CVD”, Chemical vapor deposition) method. The "HPHT" method is the most tested classical synthesis method, which can be used both carbon deposition on diamond from flux melts and catalytic reactions. In "CVD" synthesis, diamond growth occurs on a seed during carbon deposition mainly from a gaseous medium at relatively low temperatures and pressures. The bulk of synthetic diamonds are relatively easy to diagnose by such features as photoluminescence, electromagnetic properties, and optical features. But among synthetic diamonds there are also those that outwardly do not show the properties characteristic of most synthetic stones. It is for their determination that relatively complex special equipment is required, which makes it possible to determine the characteristic features of a diamond grown under artificial conditions, which are not detected by most simple gemological diagnostic methods. For this reason, it is necessary to confirm the nature of the origin of diamonds in a specialized gemological laboratory.

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