Chen Qiwu - Love Diamonds Half a Century

1. Engaging in artificial diamond research is the responsibility and mission entrusted to him by history.

Professor Chen Qiwu graduated from the Department of Mathematical Mechanics of Tsinghua University in the second half of 1962 and was assigned to the Changsha Institute of Mining and Metallurgy of the Chinese Academy of Sciences to work on pressure processing theory research. He worked for less than three years. Due to the needs of new research at that time, Professor Chen Qiwu arrived in 1965. The Institute of Metal Research of the Chinese Academy of Sciences is engaged in research on refractory metal materials and explosive forming. In 1968, the task was successfully completed.

On December 6, 1963, China successfully developed the first diamond. After Professor Chen Qiwu returned to the mine, since the diamond was carried out in a closed high-temperature and high-pressure synthesis chamber, the synthesis and transformation process was difficult to directly observe and test, and there were many kinds of materials that could play a catalytic role in the conversion of graphite into diamond. People's understanding of the catalyst material is still in a state of chaos, and the exploration and development of the "Shen Nong tastes the grass" style has begun , but the results have been minimal. Therefore, in order to overcome the bottleneck of the development of the artificial diamond industry, we must first understand the mechanism of action of the catalyst material. At that time, he was the deputy director of the second room. He and the comrades of the second room of materials (Wang Yaoshu, Yang Deqing and Liu Shuzhen, etc.) carried out a large number of research and development work on Ni70Mn25Co5 flaky catalyst. On this basis, he was appointed as the team leader at the end of 1975. The Catalyst Materials Research Laboratory of the Institute of Mining and Metallurgy developed the Nb-containing 2# catalyst (NiMnCoNbCu). In 1986, it introduced the 86-8# catalyst containing Cr and Si. In 1993, it developed a CHS catalyst containing a considerable amount of Fe. Among them, " Man- made diamond boron-containing catalyst alloy containing boron graphite and 2# catalyst material" won the National Science and Technology Conference Award (certificate No. 0010739 ) in 1978. The Ni70Mn25Co5 flake catalyst produced by the Changsha Research Institute of Mining and Metallurgy in the company produced more than 300t of flake catalysts in 1992. In 1995, its sales exceeded 600t, and the market share was over 70%. It was retained until the beginning of this century to replace the flake catalyst with powder catalyst. It has become a typical representative product of catalysts for diamond synthesis in China's history. In the 1990s, as a doctoral student of Professor Chen Qiwu, I was fortunate to have contacted various synthetic diamond catalyst materials that he designed and developed in the 1970s and 1980s. He also carefully read the later "The Mechanism of Synthetic Diamond Catalyst Materials" ( Internal data), and the Past, Present and Future of Synthetic Diamond Catalyst Materials (published in Industrial Diamonds, No. 1, 1994), it is easy to understand and accept his diamond catalyst design principles and concepts because In the article "The Mechanism of Synthetic Diamond Catalysts", he first analyzed the composition of the diamond metal envelope by means of an electron probe, revealing the reason why the metal envelope is consistent with the composition of the catalyst matrix, and proposed the diamond growth kinetic effect - The thermodynamic potential difference between diamond and catalyst liquid phase; and in the article "The mechanism of action of synthetic diamond catalyst material", it is revealed that his impurity content of fine-grained diamond ruthenium is significantly higher than that of coarse particles, and it is almost unclearly disclosed about adding Metal bismuth as a catalyst to control nucleation, said here # 2 family must understand the mystery catalyst design, but also very clearly reflected in Professor Chen Qiwu profound understanding and use of the catalyst of the catalytic mechanism of scientific regulatory capacity of the actual diamond production process right.

After the successful development of the diamond flake catalyst, Professor Chen Qiwu began to turn to the research of coarse-grain high-strength diamond synthesis process in the early 1980s. The primary problem faced in the synthetic diamond synthesis process is the theoretical analysis basis of the synthetic process. In the past, people paid great attention to the diamond-graphite balance line in the carbon phase diagram. This is an important theoretical basis for the extraction of synthetic diamonds in the past century. Therefore, the interpretation of the complex phenomenon of diamond synthesis can only be applied to the phase diagram of carbon. In 1978, Professor Chen Qiwu’s "Dynamic Effects in the Process of Diamond Synthesis" published at the first High-Voltage Physics Conference in Guangzhou pointed out: "In fact, the phase diagram involves thermodynamic problems, only the direction in which the reaction occurs, and The way, method and speed of the reaction are kinetic problems, and the non-equilibrium phase diagram is within reach." In October of the following year, he wrote the article "Characteristics of Synthetic Diamond Growth" (at the time, the in-house confidential information, published in the "Abrasive Abrasives and Grinding" magazine, issue 5, 1986), from the boundary of synthetic diamonds. Starting from the conditions, mathematics deduced the relationship between graphite to diamond conversion process and temperature and pressure. Since then, the research on diamond synthesis has become the subject of his research group. In April 1993, the coarse particles were held in the Ministry of Metallurgical Industry. At the High-intensity Diamond Research Science and Technology Achievement Appraisal Meeting, he wrote the article "Study on the Law of High-Quality Diamond Synthesis" (published in the Journal of Geology and Exploration, 1994, No. 5), and completely proposed the theory of diamond synthetic surface. The mass equation of synthetic diamond shows that the quality of diamond depends on the synthesis temperature and pressure, which reasonably explains various phenomena in the process of diamond synthesis. It is still guiding the production of synthetic diamond industry, such as graphite-diamond in the current high-yield production. The conversion rate is so high, why the JR1 type material production requires high pressure and the like. Therefore, some experts believe that: "Chen Qiwu describes the development direction and road of the diamond industry with mathematical equations."

At the beginning of the 1980s, China's diamond industry production was still lagging behind, and a large part of the high-grade diamonds required for industrial production depended on imports from abroad. Since Western developed countries monopolize this technology, the price of high-end synthetic diamonds is completely controlled by foreign countries. In order to break this unbalanced supply and demand relationship, the state strongly advocated the introduction of artificial diamond advanced equipment and independent research and creation in the 1970s, but at that time, in the choice of synthetic diamond synthesis, the choice of two-sided top press was still used. The six-sided top press is very controversial. How does China's diamond industry develop, where to go, and different opinions. Most of them advocate spending huge sums of money to introduce foreign top technology. The use of foreign double-faced ultra-high pressure technology, high yield of synthetic diamond, good quality, has been supported by the state, but can not be attacked for a long time. After in-depth analysis of the advantages and disadvantages of the two ultra-high pressure technologies, he clearly pointed out that "the two-face top technology is inherently insufficient, and the six-face top technology is waiting to be adjusted", and strives to develop China's unique hinged six-face top technology and take the road of self-reliance and development.

In 1981, he presided over the establishment of the six-face high pressure laboratory of the mine. The purpose was to achieve high quality (50/60 thick) high strength (compressive strength ≥ 20Kg) by expanding the reaction chamber (ф23mm). Diamond production solved the urgent problem of high-strength diamond used in national drilling and sawing at that time. In 1986, he led the research group to complete the "Φ23mm cavity diamond synthesis process" project with the support of the General Bureau of Geology of the Ministry of Metallurgy. The 6×6MN synthesis equipment was used to eliminate the 6×6MN synthesis equipment that has dominated the industry for 30 years. More than doubled, the single production has doubled; the synthesis cycle has been extended, and the quality has been greatly improved. The diamond for sawing and drilling has gradually increased from 80 mesh to 70 mesh, 60 mesh, and 50 mesh, and the application fields have been expanding. The research result "Study on coarse-grain high-strength diamond--Φ23mm cavity synthesis process" was appraised by the Ministry of Metallurgical Industry in 1993. In 1994, it won the second prize of scientific and technological progress of the Ministry of Metallurgical Industry. In 1996, it won the third prize of National Science and Technology Progress Award ( Certificate number 11-3-002-01). This achievement not only enabled the research team to gradually develop and grow, but also became the second production room of the mining and metallurgy institute, the diamond factory, and even became the main product production department of Jinrui Technology, making the Changsha Research Institute of Mining and Metallurgy the most influential in China in the 1990s. One of the diamond industry centers.

Second, grasp the development bottleneck and make the artificial diamond industry take a new step

(1) Research results of six-faced high-pressure technology promoted the development of six-face high-pressure technology

The research results of "Φ23mm cavity diamond synthesis process" and the promotion and application of 6×8MN six-face press machine in the industry have started a new development stage. At that time, experts in foreign superhard materials generally believed that “currently, ultra-high pressure technology still Full of mysterious uncertainty." That is to say, during this period, Professor Chen Qiwu proposed the concept of critical volume from the "closed volume", established the design basis of the six-faced high-pressure cavity, and re-defined the ultra-high pressure technology, pointing out: "Ultra high pressure The technology is to establish the required high temperature and high pressure conditions in the specified space area and maintain the required duration." To this end, he proposed the principle of “three-in-one” of the six-face press, with special emphasis on the structural center of the equipment, the center of convergence of the anvil and the center of mass of the synthetic cavity, which should be consistent in the synthesis. be consistent. It is further pointed out that the diamond press must be a high-tech product. It is proposed that the high-pressure synthetic press should be based on the "structural rigidity"; the "100MPa hydraulic limit" principle is the norm for design and use; the press control system should be realized. PT intelligent control, etc.

Ultra high pressure technology has to solve two problems: (i) sealing of the pressure object; (ii) material of the pressure material. In order to solve the latter problem, Bridgman proposed two principles of reinforcement, namely the principle of shape reinforcement (mass support) and the principle of stress reinforcement (lateral support), so that the material problem of the anvil is turned into a technical problem. But how to achieve these two principles Bridgman did not give more information. In the process of large-scale reaction of the six-face top press, it is necessary to transition from one cavity structure to another. First, how to determine the size of the mold and pyrophyllite, the problem is the development of the industry. Too important, it is easy to happen to solve the problem, it has become a large-scale blockade. Professor Chen Qiwu proposed the concept of critical volume from the closed volume. The experiment discovered the "佯谬" phenomenon under the high pressure of pyrophyllite and established the equation for solving the critical volume, thus the parameters of the anvil and the pyrophyllite reaction chamber. The size is linked.

After the promotion and application of 6×8MN six-face top equipment in the industry in the early 1990s, Prof. Chen Qiwu’s research group carefully selected the 6×12MN six-sided top press as the second stage goal of equipment development. In 1993, Professor Chen Qiwu, as the project leader, proposed and undertaken the Hunan Province Science and Technology Research Project “Φ28mm Cavity Synthetic Process Research” (93-098B), and in the second year, he also undertook the Hunan Science and Technology Commission Science and Technology Challenge Bidding Project. "Research on the production process of high-strength synthetic diamond" (94-03). This project is another complex system engineering that integrates product structure, process, equipment, mold and raw materials. It aims to expand the synthetic cavity to achieve a compressive strength of ≥ 25Kg, a 50-mesh diamond yield of more than 5 carats, and diamond production. The economic benefits of single production and single equipment have doubled. In 1994, the task team of the project was commissioned to design and order a Φ400mm bore (6×12MN) large six-face press for the 7803 plant. The installation and commissioning tasks were completed in the summer of 1995. I had the privilege of participating in the research on the above two subjects. At the time, the experimental scene was still fresh in my memory. I was impressed by Professor Chen’s dare to be the pioneering spirit of innovation. At the same time, he also admired his five-minded attitude in the course of the experiment.

The first is the problem of carbide anvil. Although Φ400mm cylinder diameter presses have been manufactured, they use a small anvil of Φ90mm, and the cavity is Φ25mm at the maximum. To achieve the Φ28mm cavity synthesis process, the size of the anvil must be greater than Φ104mm. I remember that Professor Chen Qiwu ordered two batches (12 pieces) of Φ104mm top anvils from Zhuzhou 601 Factory and Zigong Cemented Carbide Factory respectively. Since the suppliers need to install large-scale cold isostatic pressing equipment and re-mold, these anvils The price is surprisingly expensive (like 10,000 yuan / piece). In the high-pressure synthesis test, some of the top hammers in the top hammer were cracked, and the most were thousands of times. At first we suspected that there was a problem with the quality of the top hammer, but the supplier's inspection found that there was no problem with the quality of the top hammer. On the one hand, Professor Chen arranged a comprehensive analysis and analysis of each cracked top hammer, and on the other hand carried out a synthetic test of different sizes of pyrophyllite. After extensive observation of the metallographic phase of the grinding disc, we found that the number of defects (holes) per unit area did not exceed the quality standard of the cemented carbide, and the compressive strength and bending strength were not worse than the small top anvil. The result was reported by Teacher Chen. He thought about it for a while and said to us: "As the volume of the pressure-applying mold increases, the number of defects involved increases. For the large-top hammer, it is not determined by the defect of unit volume." Later, the research team proposed that the Zhuzhou 601 factory big top hammer project team should consider using the hot isostatic pressing process to solve this problem. Now it seems that this is the best way to solve the quality problem of the big top hammer, but there was no heat at the time. In the case of static pressure, the quality problem of the big top hammer has become a roadblock.

Followed by the matching problem of the size of the pyrophyllite and the structural rigidity of the equipment. Although the results of the synthesis test of different sizes of pyrophyllite blocks have obtained a good composite block size, the service life of the top hammer is still low. Professor Chen Qiwu believes that this may be related to the deformation of the equipment in addition to the quality of the carbide top hammer. On the one hand, the research team began to negotiate with the relevant personnel of the 7803 factory whether there is a problem with the materials used in the design of the hinge beam of the equipment. However, the other party firmly believes that the 45# steel design strength of the hinge beam is sufficient, and it also shows the strength check calculation of Hunan University. The results serve as evidence. Professor Chen believes that high-voltage equipment "is considered not only because the equipment can withstand much load without damage, but more importantly, it is necessary to consider the maximum elastic deformation allowed under the load, that is, the structural rigidity of the equipment." In order to prove the correctness of his point of view, Professor Chen arranged for us to actually measure the deformation in the high pressure synthesis of this press (published in Industrial Diamond magazine, Issues 3-4, 2005), and the results confirmed that The equipment has severe elastic deformation during operation and the deformation is severely asymmetrical. Based on this analysis, Prof. Chen believes that the torsional force experienced by the cemented carbide top hammer during the deformation process of the equipment may be the root cause of the short service life of the large top hammer. Therefore, he proposed that "the design of large-scale high-voltage equipment is not enough only to use the strength design as the criterion. The structural rigidity must be taken as the starting point for considering the problem, that is, the stability requirement should be taken as the criterion for equipment design." The design theory and technical problems of high-voltage equipment involved in the above-mentioned large-scale high-voltage equipment test research process have pointed out the direction for the development of large-scale six-face high-voltage equipment in China.

Some episodes in the above test are also very interesting. When the research and development team led by Prof. Chen led the Hunan Province scientific and technological research project "Φ28mm cavity synthesis process research" made a major breakthrough and began industrialization, in October 1995, "Science and Technology Daily" reported the Φ28mm cavity diamond synthesis of a company in Xianyang. Reports of significant progress in process research. Professor Chen feels very strange how the content of the report is particularly like the research work of his own team. After the investigation by the research team, it is found that a comrade of this group has inadvertently obtained the best of the pyrophyllite and hard alloy top hammer. The size and cavity structure leaked to each other. I personally feel that Professor Chen was not very angry about this matter at the time, the other party's research results (at that time, he already knew that the 6×12MN equipment hinge beam designed by Xianyang 202 was made of gun steel (35CrMo), and the equipment price was also better than 7803. The factory is much higher. It confirms the correctness of his design ideas and strengthens his determination and confidence in the large-scale six-faced equipment and large-scale synthetic cavities. Later, in order to distinguish it from the reported results, Professor Chen changed the synthetic cavity to Φ28.5mm.

(2) Using the “Huanghe Cyclone” to establish a new milestone in the large-scale production of domestic six-face top equipment

At the end of 1995, Qiao Jinling, the chairman of Huanghe Industrial Group Co., Ltd., went to the Changsha Research Institute of Mining and Metallurgy to consult Professor Chen Qiwu for the purpose of the top two diamond presses. At that time, Professor Chen first listed the diamond production and operation situation and the difficulties encountered by domestic companies such as Artificial Crystal Research Institute, Tianjin Baoyu 232 Factory, Beijing Drilling Tools Factory, Guiyang Liusha and Shenzhen Asia Company. It is pointed out that the two-face top equipment annual ring mold is the key to its technology and the key to its production cost. “The force state of the annual ring mold is not as good as the six-face top mold, which is the inherent defect of the two-side top press!”, The two-side top synthesis technology is complex, the mold precision is high, the volume is large, the manufacturing is difficult, the price is expensive, and the service life is short. In the competition with the six-face top equipment, one day will be eliminated! Then the large-scale six-face top equipment of the research group is introduced. The operation situation and the Φ28.5mm cavity process synthetic diamond situation, and clearly expressed the hope to cooperate with Chairman Joe to develop large-scale six-face top equipment and its synthetic process industrialization development. Chairman Qiao basically agreed with the opinion of Dean Chen and said that he would go back and discuss. On January 17, 1996, the two sides signed a scientific research cooperation agreement to jointly develop the "Φ28.5mm cavity synthesis process" (contract amount of 500,000 yuan). The joint research component consists of two parts. One part is that Chen’s research group is mainly engaged in the research and development of synthetic technology and the development of new equipment. The other part is the expert market research organized by the Yellow River Industry (Group) Technology Center. Installation and commissioning, process testing, personnel training, etc. of two 6×12MN prototypes purchased in the previous period. In May 1996, the research group completed the first draft of the feasibility study report on Henan Huanghe Industrial Group's investment in 100 sets of 6×12MN high-voltage equipment. At the same time, President Chen wrote the “Opinions on the large-scale equipment” (some of the contents were published later). "Mining and Metallurgy Engineering" at the end of 1996 (the third phase), it is clear that the newly designed six-face high-voltage equipment is modeled as UDS- I type, and the basic principles of large-scale high-voltage equipment design are publicly disclosed. From June 18 to 20, 1996, Huanghe Industrial (Group) Company sent Hu Baoren, Xia Hengqing, Zhang Zhan to Xianyang to inspect the operation of 6×12MN high-voltage equipment. Professor Wang Guangzu also participated in the inspection as a special representative. On June 25th, an investigation report was submitted, stating: "The 6×12MN press and top hammer are mature for ф28mm cavity production, and the economic benefits are considerable. The industrial production of ф32mm cavity is not mature yet.” Purchased two 6×12MN prototypes, completed installation and commissioning, process testing, personnel training, etc. in 3-6 months. At the same time, based on the project demonstration report provided by us, we submitted and submitted “6×12MN six-sided top to the company. Press Synthesis DIA Benefit Analysis report.

Soon after, the company purchased two 6×12MN (ф400mm) high-voltage equipments from the Changsha 7803 plant, which was the same as the research group. In October 1996, Cao Qingzhong, Zhang Zhan, Zhang Kui, who worked at the technical center of Huanghe Industrial (Group) Co., Ltd. Chen Hao, Liu Shufeng and others completed the installation and commissioning of the equipment. Dr. Chen’s team sent He Lizhou, Li Qiquan, Zheng Risheng and others to guide the synthesis process. However, the diamond synthesis effect on these two presses was not ideal. . In August 1996, President Chen invited Professor Zhang Zhiyuan from the Guilin Institute of Geology and Professor Han Zheng from Jiaozuo's military factory to come to the Changsha Research Institute of Mining and Metallurgy to discuss the design and layout design of the new large press. I participated in them. Most of the key technical issues are discussed, and as a sketch of Professor Zhang Zhiyuan's sketches, some of these processes are understood. At the beginning of the design, Dean Chen proposed the following basic design ideas for the two experts: (1) For the large-scale operation of the six-face top ultra-high pressure equipment, the focus should be on high-quality diamond synthesis; (2) The equipment that can synthesize diamonds is called diamond press. The design of synthetic equipment should be based on the idea of ​​improving the "structural rigidity". While improving the structural rigidity, the coordination of deformation should also be considered. (3) From three Aspects (design, manufacture, use) to improve (prolong) the maintenance cycle of the equipment; (4) use the microcomputer control technology to transform the traditional hand-work-style production mode, improve the control function and precision of the synthetic equipment. After many discussions and consultations, President Chen decided to adopt some new techniques of Professor Zhang Zhiyuan's design in the six-sided top press , such as the "double bottom support" structure of the working cylinder, the flat bottom structure of the hinge beam and the elastic gapless pin design. The hydraulic system's dual pump oil supply, front chamber back pressure adjustment synchronization and "liquid resistance contact limit" device, and proposed control system using pressure measurement and control instrument and industrial computer joint control program and constant power control technology. The new press design has begun to reflect President Chen’s thinking about the design of a large six-sided press.

Professor Chen Qiwu as the project leader joint research team undertook the Henan Provincial Science and Technology Commission's 1997 major scientific and technological research project "High-grade synthetic diamond synthesis new process equipment development research" ( No.971110214, 900,000 yuan), proposed new type of research The domestic UDS-I large-scale high-pressure synthetic equipment is required to stably realize the ф30mm cavity diamond synthesis process, and the synthesis cycle is up to 30 minutes, so that the high-grade diamond enters the international market with great competitiveness. In February 1997, the first prototype was designed, manufactured, and installed and tested for synthesis. According to Dean Chen, the first synthetic test of the new design press showed HHD30 high-quality diamond. At the same time, compared with the two purchased equipment, the sound was much smaller during the synthesis process. The deformation test results in the press synthesis process were fully confirmed. His correctness regarding the rigid design principle of large six-face top equipment. In the same year, the mass production test was carried out in Φ30mm synthetic process in April, and more than 5,000 times of synthetic diamonds were produced at the end of June. At the same time, the second prototype controlled by the computer began to debug. In July, the two prototypes were put into batch test at the same time, and the other inspections of the equipment were also interspersed. In August, the pilot test of high-quality diamond synthesis industrialization was carried out. The results show that compared with the Φ23mm cavity synthesis process at that time, the Φ30mm cavity synthesis process has a substantial increase in single-yield or high-strength diamond single-production, especially preliminary. The test results show that breakthroughs have been made in high-quality (strength ≧200N) diamond synthesis, and high-quality diamonds are no longer just patents for two-sided top synthesis technology!

The large-scale launching of the UDS-I large-scale high-pressure synthetic equipment of Huanghe Industrial Group Co., Ltd. and the Ñ„30mm cavity diamond synthesis process were successfully promoted and applied, which created obvious economic benefits and contributed to the successful listing of the company at the end of 1998 and became the largest diamond production in Asia. Enterprises, especially the Yellow River Industrial Group Corporation, use this equipment to produce HHD30 products that have been tested by Japan's ODK company. The performance is close to foreign high-end products, setting a new milestone in the large-scale domestic six-face top equipment.

In 1998, the research results of " UDS-I high-pressure synthetic equipment and Φ30mm cavity diamond synthesis process" jointly completed by Chen Qiwu as the first completion person, Huanghe Industrial Group Corporation and Changsha Research Institute of Mining and Metallurgy won the second prize of Henan Science and Technology Progress Award ( Certificate number 9901 ) .

(III) Develop Y-500 synthetic press to promote large-scale domestic six-sided press

In September 1999, according to the needs of the development of superhard materials industry in Hunan Province, the Hunan Provincial Science and Technology Commission issued a key project for the “High Quality Synthetic Diamond Research” project of Hunan Province’s major industrial science and technology research project, Chen Qiwu, of the Changsha Research Institute of Mining and Metallurgy. .99GKYl007, 200,000 yuan), requires a step on the basis of UDS-I equipment and Φ30mm cavity synthesis process. The implementation of this systematic engineering research requires a strong economic foundation as a supporting condition. The leaders of Hunan Investment Group Co., Ltd. have a unique eye and joined the industry and become a strong support force. In the same year, Chen Qiwu's research group and Hunan Investment Group Co., Ltd. carried out related industrialization cooperation (contract amount of 900,000 yuan). In July 1999, the company began to develop Y-500 diamond synthesis equipment and developed ф40-ф42mm cavity diamond synthesis process. At the end of December, the Y-500 high-voltage equipment trial production was completed, and the commissioning work was completed in mid-January 2000. By July 2001, a total of 44 Y-500 equipment were manufactured. The first equipment was sold to Zhengzhou Xinya Composite Superhard Materials Co., Ltd., and this equipment was used to produce Φ25.4 diamond composite sheets (PDC). This is the largest specification product that can be produced in China at present. It is in the leading position in China; the second equipment is used in the Φ42mm cavity powder catalyst diamond synthesis test of this group, and then increased by 4 units; the third equipment is exported to Korea for production. Φ30mm diamond composite sheet (PDC); Hunan Investment Group Co., Ltd. owns 15 units, and the remaining 22 units are sold to Hengyang Jingkewei Industrial Co., Ltd. The Y-500 high-pressure synthesis equipment was appraised by the Hunan Provincial Science and Technology Commission in July 2000. The conclusion of the expert appraisal is: Y-500 diamond synthesis developed with the guiding principle of “pressure limit” and structural rigidity theory. The equipment is rigorous in calculation and reasonable in design. It is the largest six-face press machine available for industrial production in the world at that time. It achieves the best coordination of man and machine, and its performance (structural rigidity, running accuracy and operability) is at the international leading level. . Experts agree that the Y-500 high-pressure synthesis equipment has the characteristics of serialization of equipment, which is of great significance to promote the development of high-voltage equipment throughout the industry. In 2001 , the " Y-500 Diamond Synthetic Equipment and Synthetic Process Research" was awarded the second prize of Hunan Science and Technology Progress Award . Taking the Y-500 high-voltage equipment as an example, the Φ500mm bore diameter equipment has developed into the mainstream equipment in the industry in the first decade of this century. With the large-scale process, the particle size and quality of diamonds continue to increase, and the output rises linearly, effectively driving the industry to a new level.

(4) Established a theoretical system of diamond synthesis and developed a series of new diamond varieties

In 1978, at the "National First High-Voltage Physics Symposium", Professor Chen read the paper "Dynamic Effects in the Synthetic Process of Synthetic Diamonds", pointing out that discussing the synthesis process on the carbon phase diagram is a conceptual confusion, followed by an in-depth In 1993, the theory of "Diamond Synthetic Surface" was completely proposed. The first time, the so-called "synthesis zone" on the carbon phase diagram was given a correct and in-depth explanation, and the diamond mass equation was derived, further revealing the synthesis of synthetic diamond. The law enriches the theory of diamond synthesis.

In 1981, Professor Chen Qiwu synthesized needle-shaped diamonds to fill the domestic gap. In 1982, he published in the second issue of the Journal of Mining and Metallurgy. In 1983, he read the article "Long needle-shaped diamond" at the Second National High-Volume Symposium, and then published in the Chinese and English editions of the Chinese Physical Society. . This product is a good material for diamond grinding wheels, especially diamond dressing grinding wheels.

In the 1980s, the West was dismissive of diamond products produced in China, whether it was six-sided or two-sided equipment. In the early 1990s, the research results of the research on coarse-grained high-strength diamond-Φ23mm cavity synthesis process were carried out by Professor Chen Qiwu. After testing by American GE, it is considered that this type of diamond (JR4) produced by China using six-face top technology is a kind. Competitive products, with special attention to China's progress in high pressure synthesis technology. "After three days, when you look at each other." In 1998, Prof. Chen Qiwu visited Japan with the relevant personnel of the Yellow River Industrial Group Co., Ltd., and used the UDS-I type equipment and Φ30mm cavity technology to synthesize diamond (grade: HHD30) in Daban Diamond Co., Ltd. (ODK) and several major companies in the world. The high-end product comparison test results of GE in the United States, De Beers in the United Kingdom, and Rijin in South Korea showed that the impact toughness and thermal stability of HHD30 showed a difference in thermal stability with foreign high-grade diamond products only at 1100 °C.

At the beginning of this century, the development of domestic powder catalyst synthesis of coarse-grain high-strength diamond technology was blocked. Professor Chen Qiwu found that the US GE company has a MBG600 series of four brands for the 80/400 mesh diamond: MBG-660, MBG-640, MBG- The 620 and MBG-600, of which MBG-660 is the highest brand, were quoted at $1.30 per carat. His R&D team gathered the attention of R&D on this product and developed the HTD series of high-grade fine-grained diamond products to fill the domestic gap. Because the crystal form is particularly complete, it is a hexahedral - octahedral shape , and its crystal form and performance are comparable to those of the US G•E company's MBG series.

Third, tirelessly serve the synthetic diamond industry association