Overview of the development of synthetic diamond industry in China

Diamond is the hardest substance among many naturally occurring products found on the earth at present. In addition to being used as jewelry, diamond has a wide range of industrial uses, such as fine abrasive materials, high hardness cutting tools, various types of drill bits, wire drawing dies and components of many precision instruments.

Originally, diamonds only exist in natural diamond mines. There are two main methods of synthetic diamond: high-temperature high-pressure method and chemical vapor deposition (CVD) method. In the 1950s, the United States successfully manufactured synthetic diamond with graphite as raw material under high temperature and pressure. The first synthetic diamond in China was synthesized in 1963 by the high-temperature high-pressure method, which has been 53 years old.

 

High-temperature and high-pressure method technology has been very mature, accounting for the mainstream of the world. China has now occupied 90% of the world's market share. China's annual output of high temperature and high pressure diamond is about 14 billion carats, mainly diamond powder, which is widely used.

 

Saw blades (diamond and powder metallurgy processing), abrasives, grinding wheels, marble, ceramics, cutting wafers, lenses and other superhard materials are all processed with diamond. Diamond cannot process iron and nickel because iron will react with diamond. The rest of non-ferrous metals can be processed with diamond.

 

 

China's diamond industry is mainly concentrated in Henan Province, mainly due to the Zhengzhou Institute of Abrasive Grinding, commonly known as the "Three Grinding Institute" in the industry. The technology of the Institute has successively developed three major diamond enterprises in China: HUANGHE WHIRLWIND DIAMOND,ZHONGNAN DIAMOND, and ZHENGZHOU HUAJING(CDT CO., LTD., our diamond raw materials are all from these three major suppliers and have extensive cooperative relations with them), which are also the three largest enterprises in the world. At present, the amount of diamond powder materials produced in China is 140-15 billion carats/year, with a market scale of about 10 billion yuan.

 

However, the market scale of related industries is very large, that is, diamond powder is applied to saw blade, wire saw, cutting tool, abrasive, drill and other industries. In 2013, the global market scale was about 35 billion US dollars, and China accounted for more than 60%, about 100 billion yuan.

 

After more than 50 years of development, China is a big country in diamond production and application, but not a strong country. At present, it is in urgent need of transformation and upgrading.

 

There are no problems with diamond production in China, but the follow-up technology and deep processing ability are very poor. The problem faced by the domestic diamond industry is that the high-end technology is abroad and the basic materials are in China, which is very similar to the domestic rare earth industry. For example, the classification and screening of diamond powder is difficult to achieve in China, especially for the screening of products with small size (several microns and below), the size distribution is relatively large. At present, the powder is exported to foreign countries, and then exported back after classification and screening. China is the largest producer of solar energy industry, but the wire saw for wafer processing is mainly imported from abroad.

In addition, about 90% of other high-end tools, especially ultra-precision tools, are imported. The profile accuracy of foreign ultra-precision tools can be less than 50 nm and can be mass produced, but the accuracy of domestic tools can only be 200 nm, with a significant gap. Application cases of ultra-precision tools: The aluminum alloy back shell of iPhone mobile phone is directly milled with this ultra-precision tool, which is very bright without polishing; Another case is the automobile hub of high-end cars, which is made of high silicon aluminum alloy material. General tools are difficult to process, so they can only be cut with diamond tools. The brightness after cutting with diamond tools can be relatively high.

 

Similar tools are also controlled by foreign countries; There are also optical lens cutting tools, which also rely on imports and are banned by foreign countries. The reason is that this kind of tool can not only be used to process optical lens, but also be used to cut radar reflector, gyroscope shell and other military fields.

Therefore, the follow-up high-end industry of the whole diamond industry is very deficient in China, including the selection of powder diamond materials and the preparation of large single crystal diamond.

 

Bulk single crystal diamond is produced by microwave plasma CVD at low temperature and low pressure. At present, 100% of domestic diamond is imported.

 

 

 

Industrialization has not yet been realized in China. The main problem is still in the equipment, especially the unqualified vacuum equipment in our country, which cannot be used for the production of large single crystal diamond. Moreover, even if imported equipment can be purchased (expensive, about 3 million yuan), there is no relevant preparation process, and the risk faced by investors is relatively high. In addition, such equipment exported from Japan to China is only allowed to be used in scientific research or semiconductor fields. It is not allowed to use large diamonds for precision tools.

Therefore, whether the equipment for preparing large single crystal diamond can be made domestically is the first consideration of the Jiangnan research team. Through efforts, the Jiangnan research team has upgraded and transformed the domestic equipment and successfully realized the production of large single crystal diamond, realizing the localization of the equipment. They also incubated this technology into a company to manufacture this kind of equipment. At the same time, a second company was established to manufacture large diamonds with this domestic equipment. This is the first production line of large single crystal diamond in China and the fifth company with this technology in the world. In addition, Yellow River Cyclone recently announced that it would invest in equipment and production technology of large single crystal diamond.

The development of large single crystal diamond is the promotion of the domestic diamond industry. At present, the market of large single crystal diamond is about 40 billion yuan. In addition to the traditional tool industry, it is expected that there will be very large development space and prospects in semiconductor, computer chip and other fields in the future.