Natural diamond has been discovered for nearly 3,000 years. According to records, diamonds were discovered in India in 800 BC. More than two thousand years later, diamonds were discovered in Brazil, Australia, South Africa and other countries until the 18th century in modern times. It was not until 1965 that our country began to discover native gem-quality diamonds.
At the end of the 18th century, people conducted research on diamond.
French chemist Lavoisier and others discovered that diamond is a flammable substance that turns into gas after burning. In 1797, British chemist S. Tennant confirmed through experimental methods that diamond is a crystalline form of carbon, and it is an allotrope of carbon like graphite.
Natural diamond primary ore belongs to brecciated mica peridotite (kimberlite). When the carbon element in the kimberlite located deep underground reaches a certain concentration, under high temperature and high pressure conditions, the carbon element crystallizes into Diamond crystals form diamond deposits.
Later, people have been studying the transformation of carbon into diamond under artificial conditions. In the past century and a half, many people have conducted various experiments. However, due to the lack of sufficient theoretical understanding and suitable high-voltage equipment at that time, the above-mentioned experiments were tantamount to groping in the dark, and the results were inevitably failures.
Until the mid-20th century, modern scientific knowledge laid the theoretical foundation for synthetic diamond, and the birth and continuous improvement of high-voltage devices provided the necessary means. Under these two premises, practical work began on developing diamonds using high temperature and high pressure technology.
Since around 1940, this work has made progress in the following two aspects: theoretically, starting from Rossini’s calculation of the graphite-diamond equilibrium curve below 1200°C, synthetic diamond The required pressure and temperature conditions are gradually becoming clearer; in terms of equipment, on the basis of P.W. Bridgiman's anvil and through the efforts of F.P. Bundy, H.T. Hall and others, In 1953, the Belt double-sided ultra-high pressure device was successfully designed. On the basis of these developments, finally on December 16, 1954, physical chemists H.T. Hall and F.P. Bundy of General Electric Co. (GE) successfully trial-produced In 1955, the first report of reproducible synthetic diamond was published in human history. At that time, diamond was first synthesized by using a Belt-type device to add iron-containing substances (troilite) to graphite. Later in 1960, Liander and Rembrandt (Lundblad) of the Swedish ASEA company claimed that they had successfully synthesized diamond using graphite and metal carbide on a six-sided top press as early as 1953. However, it was not announced at the time.
Shortly after the advent of artificial diamond, another artificial superhard material appeared - cubic boron nitride (CBN). At present, natural CBN has not been found in nature. It was discovered in 1957 by R.H. Wentorf, another physical chemist of General Electric Company in the United States, using high-pressure and high-temperature technology similar to synthetic diamond in the presence of a catalyst. Synthesized. It soon entered industrial production.
Since the successful development of artificial diamond in 1954, significant progress has been made in the research of synthetic diamond by static pressure catalytic method.
In 1961, Decarli and Jamieson successfully synthesized diamond by explosive method for the first time under the impact force of 30GPa.
In 1962, Bondi realized the direct transformation of graphite to diamond without a catalyst under a static pressure of 3000K to 4000K and a static pressure of more than 12GPa, and measured the triple point of diamond, graphite and liquid carbon as : 4100K, 12.5GPa.
In 1966, Dupont successfully studied the impact-quenching method of explosive synthetic diamond based on the work of De Calle and others, and put it into industrial production. In the same year, Hall successfully developed Mega-type diamond powder sintered body (polycrystalline).
In 1970, Wentov successfully obtained artificially grown gem-grade large-grain diamonds with a size of approximately 6mm and a weight of 1 carat (1 carat = 0.2g).
In 1972, the Compax type sintered body was put into production in the United States, opening up a new way to manufacture polycrystalline composites.
After the 1980s, research on artificial diamond films has set off a boom, and it is expected to enter the industrialization stage at the beginning of the 21st century. Superhard material films are called new materials of the 21st century.
The development history of the application of superhard materials in the industrial field over the past 40 years has gone through the following stages:
The 1950s was the stage of research and development and initial industrial establishment, and small-scale production began in the United States. Production.
The 1960s was the beginning of the industrialization stage, and industrial production began to take shape. However, due to restrictions on patent rights, industrial production is controlled by a few countries and monopolies. During this period, diamond was mainly used to make abrasive tools, playing a supplementary role in grinding processing, and was used for high-precision and low-roughness processing of hard and brittle materials.
In the 1970s, diamond abrasive tools developed rapidly; at the same time, the application scope of diamond expanded to drilling tools and cutting tools.
In terms of grinding tools, diamond grinding has expanded from fine grinding to rough grinding, form grinding, powerful grinding and other fields. Superhard materials (diamond and cubic boron nitride) replace ordinary abrasives (silicon carbide and corundum) and have become a major development trend in the world's abrasives industry. This progress, from the perspective of abrasive manufacturing, can save energy, improve working conditions, prevent environmental pollution, and facilitate the automation of the production process; in terms of use effects, it can improve the quality and efficiency of grinding processes and the service life of abrasive tools. .
In terms of drilling tools, geological drill bits and petroleum drill bits made of diamond single crystal and polycrystalline (including polycrystalline sintered body and polycrystalline composite) have replaced steel grains and cemented carbide drill bits and achieved remarkable results. , not only can drill through the hardest rock formations that are difficult to drill with steel drills, but also the drilling speed is fast, which can be increased by 1 to 2 times. The well body is straight and the hole is small, and small diameter drilling can also be achieved. Therefore, diamond drill bits have become the development direction.
Diamond polycrystalline cutting tools have been used since the 1970s to replace carbide cutting tools and show unparalleled performance in processing hard, brittle and difficult-to-machine materials. The subsequent cubic boron nitride polycrystalline cutting tools also achieved great success in processing difficult-to-machine materials such as hard and tough alloy steel, and thus became necessary and useful in the 21st century such as advanced CNC machine tools and flexible processing systems. A new type of processing tool with broad development prospects.
In the 1980s, diamond sawing tools developed rapidly and became one of the three largest types of diamond tools, alongside diamond grinding tools and drilling tools. In addition to being mainly used for natural and artificial stone processing, diamond sawing tools are also used for sawing highways, airport runways and concrete building components.
In the 1990s, both superhard material single crystals and polycrystals, and superhard material tools have entered a comprehensive development towards the goals of high quality, low cost, multiple varieties, specialization, and serialization. a new stage of development. During this period, stone processing tools continued to develop rapidly, and their diamond consumption exceeded the consumption of abrasive tools and rose to the first place. In our country, among the various types of diamond tools developed and applied, diamond tools for mining stone, plate sawing and surface grinding and polishing have become the largest category, accounting for about 50% of the total.
At present, the composition ratio of various types of tools in superhard materials (including diamond and cubic boron nitride) at home and abroad is arranged in the following order: grinding tools and their dressing tools (about 30%), sawing tools (about 30%), cutting tools (about 15%), drilling tools (about 15%), other tools (about 10%).
Over the past 40 years, artificial diamond has gone from "superabrasives" (to 1970) to "tool materials" (to 1985), and from the second half of the 1980s (after 1985) due to the The mass production of high-quality single crystal particles and the advent of diamond films have brought diamond and cubic boron nitride into the "functional materials" stage. Due to full utilization of diamond's excellent optical, electrical, thermal, acoustic and other properties, it has been widely used in the electronics, computer, and aerospace industries.