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Basic knowledge of super hard materials

Superhard material with other incomparable special properties, has become the industry application can not be replaced in the field of new materials, has been widely used in metallurgy, oil drilling, construction engineering, mechanical processing, instruments and meters, electronic industry, aerospace, and modern cutting-edge science, dosage the biggest stone material industrial setting out of superhard materials and its tools is very difficult to develop. Today, I want to take a look at some of the materials you need to know about hard materials.

What is a super hard material?

The superhard material is the material that the hardness can be compared with diamond. Currently in use of superhard materials is mainly with diamond and cubic boron nitride but there are a lot of superhard materials is developing, such as boron carbide, twin crystal diamond, such as silicon carbide compounds between III and IV.

Diamond is the hardest substance in the world now known, and the hardness of the C60 is probably no less than diamond, but it is not yet conclusive. The hardness of cubic boron nitride is next to diamond. The hardness of these two superhard materials is much higher than the hardness of other materials, including the hard materials such as corundum, carbide, carbide and high speed steel.

Therefore, the superhard material is suitable for the manufacture of other materials, especially in the processing of hard materials, with incomparable superiority and an irreplaceable important position. Because of this, super hard materials have been widely used in industry. In addition to used to make tools, superhard materials in optical, electrical, thermal, has some special properties, is a kind of important functional material, has attracted high attention, the properties and USES are constantly research and development.

History of superhard materials

The development of super hard materials in China has been synthesized from the first laboratory in 1963 and has been in the process for more than 30 years. From scratch, from small to large, from laboratory to commercial production, we have become the world's largest diamond producing country, and the production of synthetic diamond has ranked no.1 in the world. Figure 1 summarizes the six development processes of superhard materials. The diamond and cBN superhard materials that have been widely used in industrial applications have been developed from monocrystals to polycrystalline and new superhard materials in the following stages:

In 1796, British scientists Tennant by burning famous diamond carbon dioxide experiment reveals the diamond is made of pure carbon composition, for the first time since humans began to explore the synthetic diamond. After attempts and efforts, until the 20th century, by Simon and Berman Graphite were obtained through the experiment and speculation - Diamond equilibrium phase diagram (by repeated after perfect equilibrium phase diagram is shown in figure 2), to make synthetic possible.

In 1953, Swedish Liander et al. successfully synthesized diamond from high temperature and high pressure (HPHT) technology. Subsequent research has shown that, if add boron oxide, nitride, lithium and calcium or magnesium nitride nitride catalyst, synthesis of pressure and temperature can be reduced to 4 ~ 7 gpa and 1200 ~ 1700 ℃, the preparation of diamond and cBN crystallites are mainly used for abrasive. Relatively speaking, the preparation of large particle single crystal cBN is difficult, and the maximum is 1 to 3mm. The research and preparation of gem grade diamond in China mainly focus on jilin university, Yellow River cyclone and zhongnan diamond and other research units and companies.

2.3 CVD technology synthetic diamond development stage

CBN membrane material prepared for CVD method, although in the preparation of cBN membrane were reported in 1979, but not until 1987 did reports suggest that cBN film were prepared on real significance, the study found that generally in the matrix and other BN structure transition between cBN membrane layer and affect the adhesion. With the development of science and technology, the thickness of cBN film has reached 2 ~ 3 mu m, and the adhesion of the substrate is continuously enhanced.

2.4 nano-grade diamond micropowder preparation and development stage

It was not until the 1990s that nano-sized diamond microcrystals, which were synthesized from the explosion method, entered the market. This method was able to obtain 5nm microcrystals due to the extremely fast cooling speed.

2.5 single crystal diamond tool development stage

About materials research scholars in the 1960 s to the natural diamond, synthetic diamond and cubic boron nitride by simple bonding or welded directly applied to the cutting of materials after grinding and other mechanical processing.

2.6 polycrystalline diamond and polycrystalline cubic boron nitride material development stage

Landmark is often thought to be the GE company production of PCD compact (with cemented carbide as the carrier, on which the formation of 0.3 ~ 0.7 mm thick layer of PCD), since then many countries and companies have launched research and preparation of PCD and PcBN.

2.7 development stage of new super hard materials

In the 1990s, companies and research institutions in the world's superhard materials industries began to develop new super-hard materials. With the deepening of the research and development, it was found that the lighter elements like carbon and boron, nitrogen and oxygen atoms in the elemental or compounds, and the lighter elements and transition element clusters (W, Re, Ir, Pt, Os, etc.) to form the compound has high hardness, its high hardness is mainly derived from the above elemental and compounds can form high atomic stacking density, super strong covalent bond of three-dimensional network structure, key high binding energy, have high ability to resist the external force, as shown in figure 3.

The superhard materials are now prepared and studied

(a) superhard compounds formed between diamond or diamond and B, N, C and O elements; (b) superhard compounds formed between the transition metal and b, N, C, and O elements.

3.Types of superhard materials

No matter how the superhard material is defined, for the time being, the superhard material mainly refers to the diamond and the cubic boron nitride and related materials.

diamond:Diamond is known as the hardest substance in nature, and has extremely high thermal conductivity and large band gap and high dispersion rate.

These excellent physical properties make diamond an irreplaceable important position in industrial cutting, heat conduction equipment manufacturing, optical device manufacturing, and electronic equipment manufacturing. The excellent properties of diamond, especially its super-strong hardness, are derived from its electronic hybridization, so that all four valence electrons are involved in bonding, forming a three-dimensional covalent bonding network.

Cubic boron nitride

And corresponding cubic boron diamond nitrogen structure, because its also has SP3 key covalent network, also has high hardness, cubic boron nitrogen is actually hardness is second only to diamond superhard materials. Although cubic boron nitrogen is less hard than diamond, but has better thermal stability and chemical stability, it is used in high temperature devices.

On the one hand, vigorously develop related to synthetic diamond and cubic boron nitride derivative hard materials to meet the current industry and the need of the development of the science and technology, on the other hand, spare no effort to explore other new types of superhard materials.

Fuller's stone: Howe no doubt asked, fullerite's synthetic success is of great significance to the processing of a series of materials such as super metal. However, the industrial production of fullerite will still have to deal with the related super high pressure.

Carbon nitride: The structure of nitride carbon was proposed in 1985. This compound has the same structure as silicon nitride. At that time, it was predicted that the hardness could be greater than diamond.

Boron nitride nitride:In nature, there may be a small amount of zinc mineralized boron nitride. It has a structure similar to that of a diamond, but the atoms are different. In wurtzite boron nitride, the boron and nitrogen atoms are set into tetrahedron, but the Angle between the adjacent tetrahedron is different, the hardness of wurtzite boron nitride may be related to its toughness of atomic bonds.

longsdale:In terms of crystal structure, lang styles also known as the six-party diamond, stone six-party carbon element with different crystal lattice is, in nature, is a rare mineral graphite containing meteorite impacts were formed when the surface of the earth. To honor the Irish crystallographer Kathleen longsdale, the name is longsdale.

Heterogeneous diamond:Heterogeneous diamond is a kind of super hard material containing boron, carbon and nitrogen, also known as cubic boron-carbon-nitrogen, which is a polycrystalline material of nanocrystals and ultrafine powders, which is slightly blue-black.

Metal boron:Metal boride electronic state density reflects the metal characteristics, and boron atoms and the extensive property between metal atoms with boron atoms between covalent bonds can result in high hardness, thus cause the attention of superhard material industry, in addition, it like carbon is a superhard material needs high temperature and high pressure conditions for synthesis, and facilitate a lot of synthesis under atmospheric pressure. The metal boron which is currently being studied is boron diboride, rhenium boride, ruthenium diboride and boron carbide. Because the metals such as osmium (Os) and rhenium (Re) have high electron density, large volume elastic modulus, small atomic radius, and orientation of boron, highly controlled.

Nanostructured superhard materials:The superhard materials of nanostructures are non-intrinsic superhard materials, such as nano-sized diamond groups, which have proved that the hardness and toughness are greater than that of ordinary large particles. One of the common forms is the polymeric diamond nano bar, which has a hardness of 150GPa and is known as one of the hardest materials known.

The largest underground factory in Asia: high-end precision machine tools, China's machine tools are cut by 30%

In the nineteen major reports, it was pointed out that the reform should be deepened to accelerate the revitalization of old industrial bases such as northeast China. Indeed, compared with the developed coastal economic belt, the northeast economy, and revitalize, want rapid ascension is not an easy easy, 19 big report, xi greatly for economic revitalization in underdeveloped regions, also the prescriptions, pointed out the direction, the report pointed out that innovation is the first in the development of leading power, is the strategic support of construction of modern economic system. We need to target the world's leading scientific and technological frontier, strengthen basic research, and achieve a major breakthrough in forward-looking basic research and leading original results. This is a new era in which the quality of China's economy needs to be accomplished. Xi's big demand is that the concrete deployment of economic revitalization will be implemented, and how will it work?

The 14m underground building is a 25,000-meter-long, high-precision workshop

Dalian, a northern city that has been born to the sea, has a "northeast window", "the pearl of the north" and the "capital of romance". It is also the opening window and the largest port city in northeast China.

On June 23, 2014, on this fertile soil in the liaodong peninsula, a plate of the eagle, like a baby eagle, attracted the attention of the world. It is the 10th new China, the first state-level new area in northeast China, the jinpu new area. New district is located in the core dayaowan port area of dalian northeast Asia international shipping center, with more than 160 countries and regions of the world's more than 300 port trade, with a total area of 2299 square kilometers, is the current national 19 national stacking area's largest district in the new city.

Along the 431km coastline, the largest underground production plant in Asia, this special factory is 14 meters from the ground and covers an area of 15,000 square meters.

In front of the five-axis machine tools, machine is a equipment in military products precision on the turbine, the turbine on the surface of all surface must demand on one-time milling machine tool, the error requirement is within three over one thousand of a millimeter, which is a third of the diameter of a human hair, can produce such a level of product precision machine tools, in any country, are regarded as strategic materials.

Dalian koyo technology group chairman de-hai yu: the most worthy of our relief, of these the key parts of the machine tool, for example, sensors is equivalent to the eye, the control system is equivalent to the human brain, so these key features are used more than ten years, the accumulation of technology produces its own, that is to say we now produce five-axis machine tools, its increase rate is the highest in the world.

Yu dehai, senior engineer of China CNC machine tool, began to enter the research and manufacturing field of numerical control system in 2000. Chen hu, Ph.D., director of the national engineering laboratory of China's advanced CNC machine tool control and integration technology. The team is working on developing high-end numerical control machine tools in key areas such as aviation, aerospace and Marine engineering. They are trying to change the history of China's high-end numerical control system. The workers are assembling and accepting a large, high-end CNC machine for military production. The machine tool USES the CNC system developed by Chen hu. The unending precision is the challenge that Chen has to face every day.

Dalian koyo technology group chief engineer Chen tiger hu: the whole blade parts eventually to a few percent mm accuracy and precision manufacturing such parts as the equipment, its actual motion accuracy higher than this, usually want to millimeter less than one percent.

More than 90 per cent of China's high-end machine tools have been equipped with numerical control systems for foreign companies, with foreign companies taking 40 per cent of the cost of the whole machine and only "empty shells" left in the machine tool industry. The core technology is highly dependent on foreign countries, and more than 95% of high-grade CNC systems adopt import system. In this context, the team in dehai is rooted in jinpu new area, which is 17 years old, and in 2015, the magic spell that plagued China's machine-tool production was finally broken down in jinpu new district.

After Chen tiger hu: we developed this machine, imported equipment dropped by more than 30%, so said China's manufacturing to machine example is very typical, we must to high-end development, to participate in the international competition on higher.

To compete with the world's advanced level, for a five-axis CNC machine, it means to control two thousand times a second. At the same time, the temperature change will result in the change of 12 micron length. The machine has thousands of parts, which must be in pursuit of the precise manufacturing environment with constant temperature and humidity.

De-hai yu: because the heat bilges cold shrink, this is the law of nature, one meter long metal temperature change at one time, it will change 12 micron, so our production of machine tools, user require the positioning accuracy of each meter is around 3 to 5 mu.

In the south of the free trade zone in the jinpu new district, yu dehai finally built its new plant before the snow began, and the largest underground plant in Asia began capping. The underground plant covers an area of 250,000 square meters, equivalent to 30 soccer fields. The workshop's canopy is made from 3,300 42-ton concrete prefabricated panels, which will be returned to the ground after the completion of the project. The plant will be located 13 meters underground. In the jinpu new district of dalian, the largest constant temperature and humidity production workshop in Asia will produce 4,000 high-end precision machine tools each year. On this point alone, the significance of the new area on the economic map of China has been highlighted.

De-hai yu: first is replace imported domestic aerospace field, and then replace imported in civilian areas, on the basis of replace imported put our cost-effective five-axis machine tools to the international market.

From imitation and pursued, beyond, de-hai yu team are benefited from the growth of dalian Jin Pu district strong foundation of the modern industrial system, and Asia's largest underground factory built, will mark the Jin Pu district of high-end equipment manufacturing industry cluster formation.

Wang qiang, director of the dalian Jin Pu new district management committee: once it is 25 square underground plant put into production, CNC machining center formed after mass production, the price of the entire numerical control processing center costs down, so can make our country a large number of small and medium-sized manufacturing enterprises will be able to have the opportunity to conditionally, access to these advanced equipment. The production capacity will improve the level of equipment manufacturing in our country as a whole.

Rooted in the northeast old industrial base of deep soil, through the adjustment of industrial structure upgrade, high mass transfer efficiency of intelligent manufacturing, radiating and driving the rapid growth of the economic dimension, and that is with dalian Jin Pu state new mission.

Yin yongjiang, deputy director of dalian municipal development and reform commission: the establishment of the dalian jinpu new area can be seen from two aspects, one is dalian city, its own special status and role, this is one. The second is the need for the revitalization of the old industrial base in northeast China.

In the first three quarters, China's output of CNC machine tools increased by 15.51 percent year on year

Recently, by the China machinery industry group co., LTD., China machine tool corporation, China machinery international cooperation co., LTD., Beijing machine exhibition co., LTD., Beijing PI trade co., LTD., assisted the 30th xun cloud technology co., LTD in China machine tool industry development BBS and operation situation in 2018 seminar (hereinafter referred to as the BBS) held in Beijing.

Leaders and guests to attend this BBS are: China machinery industry group co., LTD., vice general manager Ding Hongxiang, China machinery industry group co., LTD. Trade auto exhibition business sector director yu-qi wang, general manager of China machine tool corporation Liang Feng, former vice-minister of ministry of machinery industry at the beginning of Shen Lie, former vice-minister of ministry of machinery industry, machinery and electronics industry vice minister ming-sheng zhao, former China machinery industry federation, executive vice President of Cai Weici, machine tool of the original mechanical industry bureau chief engineer, Beijing machine tool research institute Wang Hengzhi, the original ministry of machine building engineering ShiEn precious machine tool company vice President, the former general manager of China machine tool corporation Hao Ming, former secretary of the party committee Yu Shuhua China machine tool corporation, the original company general manager Li Zhonglian based a complete set of machinery and technology of China, the ministry of industry and information technology equipment department JiXieChu, deputy director of the Han Hang, small and medium-sized business bureau of industry and information technology, business innovation service fei-yun zhang, China mechanical Cheng Yongshun international cooperation co., LTD., deputy general manager, deputy general manager of China machine tool corporation Han Guxing, instruments and meters, director of the institute comprehensive technical and economic OuYangJinSong, etc.

This BBS, presided over by the deputy general manager of China machine tool corporation Wu Fang Ding Hongxiang China machinery industry group co., LTD., deputy general manager, general manager of China machine tool corporation Liang Feng, China machinery co., LTD., vice general manager of international cooperation Cheng Yongshun for BBS welcome address. Research industry status quo

Ministry of industry and information technology of small and medium business administration fei-yun zhang entrepreneurial innovation services, the ministry of industry and information technology equipment department JiXieChu participating in the industry, deputy director of the Korea behavior analysis of China's machine tool industry related industrial policy and macro economic operation situation. The China machinery industry federation, executive vice President of Cai Weici, former vice-minister of ministry of machinery industry in the early Shen Lie, instrumentation comprehensive technical and economic research institute of mechanical industry OuYangJinSong issued the current industrial operation situation, the machine tool industry and enterprise how to implement power dream "a new era xi jinping, the intelligent manufacturing core elements and machine tool industry in action" expert reports.

Ming-sheng zhao, deputy minister of the original mechanical industry during the period of the BBS chaired a meeting of the government, industry and enterprise leaders to participate in the leadership of the old seminars, research status quo, to listen to your industry, to explore together the effective path of industrial strength and common development.

During BBS, the signing ceremony of the joint construction party of China machine tool corporation and the cloud platform was also held, and liang feng signed the contract on behalf of China machine tool corporation and the joint venture representative. Cloud platform to build party signing enterprises respectively: Qinchuan Machine Tool & Tool Group Share Co., Ltd, Wuhan Huazhong Numerical Control Co., Ltd., the first Machine Tool plant in tianjin, shandong southern Machine Tool Co., Ltd., chengdu Tool research institute Co., Ltd, vi design and research institute of mechanical industry Co., Ltd., Beijing north a Machine Tool Co., Ltd., Beijing second Machine Tool plant mechanical and electrical Co., Ltd., Beijing institute of Machine Tool Co., Ltd., Beijing guodian gaoke technology Co., Ltd.

Then, the BBS centerpiece of high-end interview will BBS atmosphere to a climax, qinchuan machine tool group Co., Ltd., general manager of Hu Hong Chen Yan: laser intelligent equipment group Co., Ltd., general manager, deputy general manager of mechanical industry design institute Co., Ltd. 6 Zhu Kaizhen, Wuhan Huazhong Numerical Control Co., Ltd., chairman of ji-hong Chen, chengdu tool research institute Co., Ltd., chairman of luo is invited to the high-end interview link, the machine tool magazine editor Liang Yu as the leader of interviews, with five companies guests talk industry development, share their successful experience.

The operation is better than expected According to the general environment, in 2017, China's machinery industry is better than expected in the first three quarters of the year, and the operation quality has been improved. In view of the machine tool industry to the national bureau of statistics data released by the analysis of China's machine tool industry in the first three quarters of production: 578100 sets of metal-cutting machine tools, year-on-year growth of 7.49%, among them 189100 sets of CNC machine tools, year-on-year growth of 0.49%; The number of metal forming machine tools was 23.84 million, a year-on-year increase of 0.69%, of which 2.13 million CNC machines, a year-on-year increase of 15.51%. The CNC equipment of machine tools was 18.55 million sets, an increase of 33.82 percent year on year. Metal cutting tools were 7518 million units, up 17.58 percent year on year.

Meanwhile, the total import and export volume of the machine tool industry in China was 197.1 billion in the first three quarters of this year, up 13.0 percent year on year, according to customs import and export data. After two consecutive years of negative growth, the recovery is growing, with a trade deficit of $2.95 billion, up 27.7 percent year on year.

The ministry of commerce has made a tentative plan to abolish the qualification certification for the export of tungsten products

To continue to deepen reform of and on power, as well as the combination of the pipes, optimization services, according to the requirements of the state council, 14 September this year, the ministry of commerce issued to repeal the ministry of commerce, and modify some rules of decision "(commerce ministry make no. 3, 2017), the cancellation of administrative examination and approval rules of matters such as the cleaning, including abolished" tungsten products, antimony goods export supply enterprise interim measures for qualification (setc, foreign trade and economic cooperation ministry make no. 21, 2001).

On April 28, 2001, the state economic and trade commission of the People's Republic of China, the People's Republic of China foreign trade and economic cooperation ministry make pointed out that in order to further implement the state council [1991] no. 5 files about resource commodities such as tungsten, antimony, which protective mining, smelting, and moftec [2000] tube send documents about the relevant provisions of the standard export order no. 523, will "tungsten products, antimony goods export supply enterprises shall be promulgated by way of interim measures for qualification, shall take effect on May 1, 2001.

Among them, the qualification for the export of tungsten products is:

  • 1. Equivalent to promote ammonium tungstate (APT), production capacity of 3000 tons (including 3000 tons, similarly hereinafter) above (at the end of 2000 has the production capacity, similarly hereinafter), nearly three years export levels (APT) more than 1000 tons per year on average. Under the same conditions, enterprises with high proportion of deep processing products in the products of the products of comprehensive enterprises and export products are preferred.
  • 2. The product quality shall be certified by the national standard or industry standard and passed the national ISO9000 quality system certification, and the enterprise undergoing the certification of quality system shall complete the certification by December 31, 2001.
  • 3. The recovery rate of the main technological process of tungsten concentrate to APT is greater than 95%, and the recovery rate of APT to tungsten powder is greater than 97%; The total recovery rate of antimony concentrate was more than 80%.
  • 4. Tungsten concentrate to APT energy consumption is less than 1 ton of tender coal/ton yield, APT to tungsten powder energy consumption is less than 4.6 tons of coal/ton production; The energy consumption of pure antimony smelting is less than 1.27 tons of coal/ton yield.
  • 5. Environmental protection requirements of industrial dust, waste water and waste gas are required to meet the existing standards of the state and be approved by provincial environmental protection authorities; The inspection report issued by the provincial environmental protection department shall be provided.
  • 6. Advanced equipment, main equipment, instruments and instruments were manufactured after 1990.
  • 7. The tungsten, antimony concentrate and primary products procured by the smelting enterprises are the products from the mining enterprises that obtained the mining license and the smelting enterprises which obtained the qualification for export.