Dazzling Diamonds Grown from Gases

Abstract

Natural diamonds are difficult to mine. This, combined with marketing strategies, make them expensive and once polished to sparkle, they make the kind of gift that might seal a relationship between humans. However, their utility spans well beyond their dazzle. Diamonds are the hardest of natural materials, have a high thermal conductivity that if five times that of copper. There are therefore a myriad of engineering applications, such as in high-temperature electronics, cutting tool and windows that are transparent to X-rays, microwaves and infrared radiations. Many of these applications require diamonds to have large and non-planar surfaces. This limits the use of natural diamonds in some functional applications. Diamonds deposited from a vapour can overcome these difficulties through a process known as chemical vapour deposition. Industrial diamonds are now difficult to distinguish from those that are mined, without resorting to sophisticated tests. From a chemical point of view, diamond is simply another form of carbon, but a form that is not stable under ambient conditions and so can be induced to change into graphite.