Diamonds Are an Engineer's Best Friend

New York, Feb. 14. It's Valentine's Day and, across our country, friends and lovers are shopping for champagne and chocolate-and diamonds. But it's not only brides-to-be that see a bright future in the facets of a diamond. Engineers in industries as diverse as telecommunications, computing, and even medicine have long seen a vast range of potential uses for this most unusual of crystals-from coatings for engine parts to artificial hip replacements. But, the high cost of natural diamonds has prohibited widespread use.

Enter Dr. John C. Angus, a professor of chemical engineering at Case Western Reserve University in Cleveland, Ohio, who has been able-at least in small doses-to duplicate the diamond in his laboratory. A member of the National Academy of Engineering and a Fellow of the American Institute of Chemical Engineers (AIChE), Angus has spent more than 30 years creating artificial diamond crystals through a low- pressure process known as chemical vapor deposition or CVD. Utilizing CVD has made it easier and cheaper to put the crystal's unique properties-which include hardness, low compressibility, heat conductivity, great strength, chemical inertness, and excellent electrical insulation-to work.

"Diamond Vision"

Low-pressure CVD grows diamond crystals by letting heated vapors of carbon containing chemicals deposit onto other surfaces. First documented in 1952 by William G. Eversole of Union Carbide, CVD had been dismissed by most researchers because the process was very slow and many thought that the fundamental nature of carbon would never allow it to work.

In 1968, by including hydrogen in the carbon-containing gases, Angus was able to not only prove Eversole correct, but greatly increased the earlier researcher's growth rate. Several years later, Angus found that growth rates could be increased even more by using atomic hydrogen, instead of the two-atom molecular form. Angus and his colleagues at Case Western continue to provide a fundamental scientific base for rapidly emerging technologies in low pressure-diamond and diamond-like materials. The team's most recent efforts have focused on "exploring the possibility of using diamonds for electrochemistry. Carbon is currently used in these applications but diamonds are more stable,"Angus said, pointing towards electrosynthesis of compounds, like fluorine or ozone, or sensor materials in aggressive environments as possible uses this field.

"Crystal Gazing"

When asked to name what he sees as the most significant or exciting uses for CVD, Angus starts with electronics. "Diamonds emit electrons easily, making them ideal for display purposes, such as television or computer screens. Right now, these types of displays are too expensive for home video, but, with diamond films, they might possibly be made very cheaply."

Other uses he cites were in communications ("diamonds have a higher speed of sound, making them ideal for surface wave acoustic devices used, for instance, in cellular phones"); as coolants for electronic components, keeping diodes and computer boards from overheating; in micromechanical devices now made from silicon; and, eventually, as gem stones. "It's less nutty to think about creating synthetic gem stones now than it was to think about CVD when we started our research. Right now, CVD research is just overlapping the very low range of gem stone size. It's not inconceivable that they may eventually find a way to grow crystals large enough for use in jewelry." So, along with everything else, Angus' dream of producing low-pressure diamond films could someday end up answering the dreams of brides everywhere-without straining the wallets of grateful grooms.

Most of all, Angus hopes his efforts serve as an example for those who are too quick to dismiss certain types of research efforts. As he points out, "If there's a lesson to be learned from all this, it's that we need to keep funding those 'far-out, blue sky' projects. This research was really 'out in left field' when we started. Yet, look what's come out of it."

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NOTE TO EDITORS/REPORTERS:
To receive a longer profile of Angus' work and other developments in synthetic diamond manufacturing, please contact the AIChE Communications Department at the number above.