Industrial Uses of Diamonds: An Overview

By V.I.Nepsha, chief of the ALROSA Office of Information and Advertising.

A new era in the industrial use of nature’s hardest substance began in the 1920s and 1930s. Industry found that it increasingly needed cutting tools made from hard alloys and abrasive materials. At that time, diamond powder was practically unique and unsurpassed as a material suitable for industrial use, a status it has retained to this day. The development of cutting tools made of hard alloys resulted in rapid advances in traditional mechanical engineering and great strides in what were at the time very new industries, such as automobile, aeronautical, tractor and tank engineering. Simultaneously, views on diamonds underwent a sea change. If throughout the millennia diamond had always been an object of desire, a luxury to satisfy vanity and testify to the owner’s wealth, serving as a guarantee of well-being in the face of everyday troubles, starting in the 1930s it became a sine qua non for industry.

It quickly became obvious that no country could survive or successfully compete in the market without sufficient quantities of diamonds for industrial use. Moreover, governments began to realize that diamonds were essential to national defense. In other words, diamond became one of the most important strategic materials. That is why the United States, which has almost no rough diamonds on its territory, found it necessary to create a strategic stockpile of diamonds to provide trouble-free material for industry in case access to diamond deposits was ever interrupted. Around the same period, the USSR made significant efforts to search for diamond deposits on its territory, a search that would be crowned with success in Yakutia in 1955. Starting in the late 1940s, many countries, including the United States and Russia, invested in intensive research on how to manufacture synthetic diamonds, an effort that would begin to pay off in the 1950s.

At the same time, with the invention of all kinds of new technical equipment and technologies, the need for diamonds was constantly growing. In the second half of the 20th century, mechanical engineering developed a lot of new branches, such as radio electronics, modern electrical engineering and instrument making. All of these and other new technologies besides began to use new materials with unique characteristics. Only diamond tools could provide the high efficiency, accuracy, low rate of waste of raw materials, and quality of finished surfaces needed, given the inherent difficulties of processing modern materials. At the same time, diamonds were also being more widely used in traditional areas, such as the construction industry and metal processing, which uses diamonds in rollers and for correction of grinding wheels.

The beginning of the end for natural diamond use in industry can be dated to 1957, when the American company General Electric started industrial-scale production of synthetic diamonds. By 1959, production of synthetic diamonds had reached 1 million carats a year, and since the early 1970s, the quantity of synthetic stones manufactured annually has exceeded the quantity of natural diamonds consumed by industry.

In the USSR, diamonds were first synthesized by a group of specialists from the Institute of High Pressure Physics, which was headed by L.F. Vereshchagin. A powerful synthetic diamond manufacturing industry arose in the USSR starting in the 1960s. From the 1970s until the early 1990s, the USSR was the largest manufacturer and consumer of industrial diamonds in the world.

Micropowders marked the initial stage of development for the synthetic diamond industry as a whole. Production of this kind of diamonds requires high technology, capital and energy-intensive processes. The equipment used in the world synthetic diamond industry is completely updated every 10 to 15 years. In the 1980s, polycrystal, used mainly in drill bits and chisels, and monocrystal, used mainly in cutting tools, drills and drawing equipment, took their place alongside synthetic diamond powders.

The basic reasons why diamond is in such high demand for industrial techniques are connected with its unique physical and mechanical characteristics, which give it a leading position among other processing materials. A diamond cooling device was invented in the United States, but in the USSR in the early 1970s, there was little interest in such devices. Work of this kind was almost completely suspended for a whole decade, in spite of the fact that the country boasted a surfeit of nitrogen-free natural diamonds suitable for such devices. Work on such devices resumed in the USSR in the mid-1980s, after foreign firms, U.S. manufacturers foremost among them, launched production of industrial semiconducting devices with diamond cooling components.
Demand for industrial diamonds rose faster than ever from the 1970s to the mid-1990s. Toward the end of the 20th century, worldwide industrial consumption of diamonds reached about 500 million carats a year—five times more than the amount of natural gem-quality rough mined annually around the world.

Today, the lion's share of synthetic diamond production (over 75 percent) is in the hands of two companies. One is the pioneer in industrial synthesis of diamonds—the  versatile giant General Electric, which has about 40 percent market share. The other is the giant of the gem diamond trade, De Beers, with about 35 percent market share thanks to the synthetic diamond manufacturing plant it owns in Ireland.

While significant numbers of synthetic diamonds are produced by these and other large manufacturers, the production of diamond tools is rather decentralized. The two largest consumers of industrial diamonds are Japan and the United States; the former consumes a bit more than the latter, due not only to the industrial potential of Japan, but also to its specificity. The next largest consumers are Germany, Italy, South Korea and Belgium. Together, these six countries consume more than 70 percent of all synthetic diamonds.

Among the major uses of industrial-quality diamonds are the following:

1.Operational development and sharpening of cutting tools made from hard alloys; processing of machine parts and measuring tools made of hard alloys and steel alloys; and finishing of steel and pig-iron parts.
2.Processing (cutting, grinding and drilling) of products made of high-strength and heat-resistant materials, including various kinds of ceramics, corundum, glass and other non-metallic materials.
3.Cutting of semiconductors and cutting and polishing of ferrous items.
4.Processing (cutting, grinding, polishing and drilling) of building and ornamental stones and concrete.
5.Sharpening of nonferrous metals and alloys made from them, as well as various kinds of plastic.
6.Manufacturing of copper, tungsten, molybdenum and steel wire.
7.Correction of grinding wheels.
8.Rock drilling.

Since the 1980s, diamonds have been considered an essential material for manufacturing modern-day electronic devices. The reason is that traditional semiconducting materials have in many respects outlived their usefulness, while diamonds possess a number of qualities that make possible quantum leaps in electronic engineering. During the 1980s, many research centers in the United States, Europe and Japan were actively working to demonstrate the possibility of making diamond-based semiconductor structures, which could be used in diodes, transistors, varistors, light-emitting diodes, sources of coherent radiation, etc. Although a number of these programs to develop technologies for manufacturing diamond slicks enjoyed generous financing, they all had disappointing results. It gradually became clear that if diamond were to be used as a material in electronics, it would first be necessary to develop techniques that would make it possible to incorporate homogeneous materials with stable properties in electronic components. One such technique that did appear was synthesis of diamonds by sedimentation from the gas phase (CVD), i.e., synthesis of diamond slicks at low pressure and temperature. As a result of this development, the price of diamond CVD slicks declined. 

Nevertheless, although it seemed at first that diamond would make great inroads into the electronics industry as a result of this discovery, this " second coming" has proven more elusive than expected. Still, diamond retains the strong position it has already taken in this industry. The problem now is in the production of different kinds of synthetic diamonds, both mono- and polycrystal. Regarding the tantalizing but as yet unrealized prospects for using diamond in electronics, it has become necessary to treat natural and synthetic diamonds separately.

Of course, from the very beginning of industrial production of synthetic diamonds, these stones have consistently been encroaching on niches previously occupied by natural diamonds. The replacement of natural diamonds with synthetic stones for industrial use is now close to an end. Most diamond mines stopped extracting diamonds measuring less than 1.5 mm some years ago. Large natural diamonds suitable only for crushing into powder (boart) continue to be mined only because this does not require additional outlays.

It should be noted that work on the synthesis of large diamond monocrystals never really stopped, despite the widespread consensus that arose in the early 1970s about the economic impracticality of manufacturing them. Therefore, it is no surprise that some success was achieved in this direction. Researchers from De Beers’s synthetic diamond laboratory succeeded in growing a monocrystal weighing 34 carats. Gem-quality synthetic monocrystals of 2 to 3 carats are no longer a rarity. Polished gem diamonds manufactured from such rough crystals weigh in at nearly 0.5 carats, or sometimes over 1 carat. Synthetic gem-quality diamonds mostly have yellow tints, but there are also blue and white crystals.