Synthetic Diamonds
Synthetic diamond makers are targeting the gem market first, but their product could transform many other industries, too
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Synthetic diamonds are nothing new. Producing them has been a stable business for the past half century. Today, more than 100 tons of the stones is produced annually worldwide by firms like Diamond Innovations (previously part of General Electric), Sumitomo Electric, and De Beers. Tiny synthetic diamonds are used in saw blades for cutting asphalt and marble, in drill bits for oil and gas drilling, and even as an exfoliant in cosmetics.
The first synthetic diamonds (diamond grit) were produced in the early 1950s by researchers at the Allmanna Svenska Elektriska Aktiebolaget Laboratory in Stockholm, Sweden. They did not immediately publish their work. Soon thereafter, GE researchers reported their own successful diamond synthesis in Nature.
Diamond has an extraordinary range of materials properties: It is the hardest and stiffest material known; is an excellent electrical insulator; has the highest thermal conductivity of any material yet barely expands when heated; is transparent to UV, visible, and infrared light; and is chemically inert to nearly all acids and bases. Diamond’s superlative properties are fine-tuned by impurities found in the carbon lattice–the same impurities that produce colors in naturally occurring diamond.
For materials applications that take advantage of these remarkable properties, natural diamonds have obvious flaws: They are prohibitively expensive and limited in size. “Plus, with natural diamonds, you can’t control the type or placement of dopants,” notes James E. Butler, who is spearheading attempts to study, grow, and use diamond at the U.S. Naval Research Laboratory. As a consequence, Gemesis and many others are eager to create large synthetic diamonds with carefully selected impurities–for instance, boron-doped semiconducting diamonds that could be used to fabricate diamond-based electronic devices that could stand up to heat and chemical attack.
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Excerpted with permission, Chemical & Engineering News
Copyright © 2004 American Chemical Society