Science of Innovation: Synthetic Diamonds

Science of Innovation - Synthetic Diamonds

ANN CURRY, reporting:

They are the symbol of eternal love, celebrated for their glitter and sparkling beauty. But diamonds are also precious for their remarkable properties- their hardness, durability, and resistance to chemicals and radiation, as well as their ability to withstand high temperatures, and also easily conduct heat. These properties are why scientists, engineers, and manufacturers covet diamonds for their research.

RUSSELL HEMLEY (Carnegie Institution of Washington): It is a beautiful structure, a very symmetric structure at the atomic level. And this structure and the very high density, the very high packing of the atoms close to one another inside this crystal give it extraordinary properties or behavior that you don't find in any other material or element.

CURRY: Russell Hemley is the director of the Geophysical Laboratory at the Carnegie Institution in Washington D.C. His research involves studying how different materials respond to extreme heat and high pressure comparable to what exists in the Earth's core. Such extreme conditions can only be achieved using diamond pressure anvil cells.

HEMLEY: The only way you can simulate, say, conditions you find in the earth's core under sustained pressures and temperatures is to use diamond.

CURRY: Natural diamonds themselves are created under these same extreme conditions - deep within the earth's surface, in the mantle where carbon atoms are put under intense pressure and heat, causing them to bond with one another in special ways. Over millions of years, these atoms form a crystal structure, which become diamonds, and these are brought to the surface by volcanic explosions and other geologic phenomena.

HEMLEY: You can produce diamond in other ways. But in the earth they form at high pressures and temperatures in a region of the planet where you would expect that. 

CURRY: In the 1950's, scientists applying a combination of high pressure and high temperature to graphite and metal, created the first synthetic diamonds in the laboratory.

HEMLEY: Some very fairly large crystals can be produced but it's very, very difficult and very time consuming.

CURRY: Over the years, other methods of creating synthetic diamonds have been developed. CVD, or chemical vapor deposition creates them by employing a chemical process that combines hydrogen, a carbon-containing gas, and a seed of a diamond into a chamber that is heated, creating diamond crystals. A variation of this is called MCVD or microwave assisted CVD. It uses the same energy as a microwave oven does by heating the gases in a chamber to sufficiently high temperatures in order to break down the carbon-hydrogen bonds and assemble them in a perfect crystal of diamond.

HEMLEY: That is diamond, but it’s very fine grained diamond or polycrystalline diamond and typically very, very thin.

CURRY: These developments have allowed synthetic diamonds to be used commercially in science, medicine, electronics, and manufacturing. But Hemley's research needed synthetic diamonds that were bigger and stronger than any that had been made before. In order to create them, he invented a new process by varying the amount of pressure, gas composition, and temperature in the MCVD chamber.

HEMLEY: If you do it just right, you can grow a gem diamond, and this was an astonishing finding and no one had reported this before. It was also astonishing because once you found that sweet spot, the growth just took off.

CURRY: Hemley's work in synthetic diamond manufacturing is an example of how the innovative process never really stops. By applying new ideas and techniques, Hemley and his team have been able to spur additional innovations.

HEMLEY: Innovation is about serendipity. It's making a discovery and then realizing, oh, it has this incredible possibility that we weren't thinking of.

CURRY: Hemley's research in the field of synthetic diamonds receives funding from the National Science Foundation. He has refined the manufacturing process to the point where he can now create gem quality diamonds with the same look and properties of natural diamonds.

HEMLEY: The best synthetic diamond that we produce is no different than the very best diamond that comes from planet Earth.

CURRY: Since 1999, Hemley and his colleagues have been granted 14 patents from the U.S. Patent and Trademark Office involving synthetic diamond production. These patents include a specific method for creating single crystal diamonds with a high growth rate, as well as various ways of tuning, or manipulating a synthetic diamonds' toughness, hardness, and color.

HEMLEY: I believe, ultimately, and this may be in the distant future that there won't be any limit to what you can grow if you need it. There is going to be an application for a diamond the size of a brick. We will find a way to do it.

CURRY: As Hemley continues to improve the process, his innovations are providing materials that are driving a synthetic diamond age that is bright, shiny, and very valuable to science.

• SCIENCE OF INNOVATION: Synthetic Diamonds - A Science Perspective (Grades 6-12)
• SCIENCE OF INNOVATION: Synthetic Diamonds - An Engineering Perspective (Grades 6-12)

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