ألماس صناعي

Synthetic diamonds of various colors grown by the high-pressure high-temperature technique

تمكن الفهماء من إنتاج ماس صناعي Synthetic diamond معمليا بتعريض الفحم (الكربون) لظروف من الضغط والحرارة مماثلة لما يتعرض له تحت الأرض. إلا أنه نتج ضعيفا غير متماسك البلورات كما الماس الطبيعي.

synthetic diamond (also known as a laboratory-grown diamond, a cultured diamond, or a cultivated diamond) is a diamond produced by a controlled process, as contrasted with a natural diamond created by geological processes or an imitation diamond made of non-diamond material that appears similar to a diamond. Synthetic diamond is also widely known as HPHT diamond or CVD diamond, after the two common production methods (referring to the high-pressure high-temperature and chemical vapor deposition crystal formation methods, respectively). While the term synthetic may sometimes be associated by consumers with imitation products, synthetic diamonds are made of the same material as natural diamonds—pure carbon, crystallized in an isotropic 3D form. In the United States, the Federal Trade Commission has indicated that the terms laboratory-grown, laboratory-created, and [manufacturer-name]-created "would more clearly communicate the nature of the stone".

Numerous claims of diamond synthesis were documented between 1879 and 1928; most of those attempts were carefully analyzed but none were confirmed. In the 1940s, systematic research began in the United States, Sweden and the Soviet Union to grow diamonds using CVD and HPHT processes. The first reproducible synthesis was reported around 1955. Those two processes still dominate the production of synthetic diamond. A third method, known as detonation synthesis, entered the diamond market in the late 1990s. In this process, nanometer-sized diamond grains are created in a detonation of carbon-containing explosives. A fourth method, treating graphite with high-power ultrasound, has been demonstrated in the laboratory, but currently has no commercial application.

The properties of synthetic diamond depend on the details of the manufacturing processes; however, some synthetic diamonds (whether formed by HPHT or CVD) have properties such as hardness, thermal conductivity and electron mobility that are superior to those of most naturally formed diamonds. Synthetic diamond is widely used in abrasives, in cutting and polishing tools and in heat sinks. Electronic applications of synthetic diamond are being developed, including high-power switches at power stations, high-frequency field-effect transistors and light-emitting diodes. Synthetic diamond detectors of ultraviolet (UV) light or high-energy particles are used at high-energy research facilities and are available commercially. Because of its unique combination of thermal and chemical stability, low thermal expansion and high optical transparency in a wide spectral range, synthetic diamond is becoming the most popular material for optical windows in high-power lasers and gyrotrons. It is estimated that 98% of industrial grade diamond demand is supplied with synthetic diamonds.

Both CVD and HPHT diamonds can be cut into gems and various colors can be produced: clear white, yellow, brown, blue, green and orange. The advent of synthetic gems on the market created major concerns in the diamond trading business, as a result of which special spectroscopic devices and techniques have been developed to distinguish synthetic and natural diamonds.

History

Moissan trying to create synthetic diamonds using an electric arc furnace

نطقب:Primary sources section

After the 1797 discovery that diamond was pure carbon,^[] many attempts were made to convert various cheap forms of carbon into diamond.خطأ استشهاد: إغلاق </ref> مفقود لوسم <ref>

Crystallinity

الصلادة

الشوائب

التوصيل الحراري

الاستخدامات

Machining and cutting tools

Diamonds in an angle grinder blade

References

^ 16 C.F.R. Part 23: Guides For The Jewelry, Precious Metals, and Pewter Industries: Federal Trade Commission Letter Declining To Amend The Guides With Respect To Use Of The Term "Cultured", the U.S. Federal Trade Commission, July 21, 2008.
^ Zimnisky, Paul (January 22, 2013). "The state of 2013 global rough diamond supply". Resource Investor. Archived from the original on January 28, 2013. Retrieved February 4, 2013.
^
Tennant, Smithson (1797). "On the nature of the diamond". Philosophical Transactions of the Royal Society of London. 87: 123–127. doi:10.1098/rstl.1797.0005.
See also:
- Lavoisier (1772) "Premier mémoire sur la destruction du diamant par le feu" (First memoir on the destruction of diamond by fire), Histoire de l'Académie royale des sciences. Avec les Mémoires de Mathématique & de Physique (History of the Royal Academy of Sciences. With the Memoirs of Mathematics and Physics), part 2, 564–591.
- Lavoisier (1772) "Second mémoire sur la destruction du diamant par le feu" (Second memoir on the destruction of diamond by fire), Histoire de l'Académie royale des sciences. Avec les Mémoires de Mathématique & de Physique, part 2, 591–616.

Bibliography

Barnard, A. S. (2000). . Butterworth-Heinemann. ISBN .
O'Donoghue, Michael (2006). . Butterworth-Heinemann. ISBN .
Spear, K. E. & Dismukes, J. P. (1994). . Wiley-IEEE. ISBN .

External links

اقرأ نصاً ذا علاقة في

a letter refuting an early attempt to create a synthetic diamond.

Wild, Christoph (2008) "CVD Diamond Properties and useful Formula" CVD Diamond Booklet.
J. Davis (2003). "The New Diamond Age". Wired Magazine. 11 (09). Retrieved June 6, 2009.
"Putting the Squeeze on Materials". Retrieved May 5, 2009.
Srikanth, Varanasi; Akaishi, Minoru; Yamaoka, Shinobu; Yamada, Hirohshi; Taniguchi, Takashi (January 21, 2005). "Diamond Synthesis from Graphite in the Presence of MnCO3". Journal of the American Ceramic Society. 80 (3): 786–790. doi:10.1111/j.1151-2916.1997.tb02900.x.
Kennett, D. J.; Kennett, J. P.; West, A.; West, G. J.; Bunch, T. E.; Culleton, B. J.; Erlandson, J. M.; Que Hee, S. S.; Johnson, J. R.; Mercer, C.; Shen, F.; Sellers, M.; Stafford, T. W.; Stich, A.; Weaver, J. C.; Wittke, J. H.; Wolbach, W. S. (July 20, 2009). "Shock-synthesized hexagonal diamonds in Younger Dryas boundary sediments". Proceedings of the National Academy of Sciences. 106 (31): 12623–12628. Bibcode:2009PNAS..10612623K. doi:10.1073/pnas.0906374106. PMC 2722287. PMID 19620728.CS1 maint: uses authors parameter (link)
Yarnell, Amanda (2004). "The Many Facets of Man Made Diamonds". Chemical & Engineering News. 82 (5): 26–31. doi:10.1021/cen-v082n005.p026. ISSN 0009-2347.
Schulz, William. "First Diamond Synthesis: 50 Years Later, A Murky Picture Of Who Deserves Credit". Chemical & Engineering News. 82 (5). ISSN 0009-2347.