The birth and promotion of artificial diamond in China

Since 1961, we have designed and manufactured the Type 61 ultra-high pressure high-temperature device. After the cooperation and cooperation of the brothers, we finally synthesized our first synthetic diamond on December 6, 1963. We spent three years investing 300,000 yuan to complete this difficult research project, making China the sixth country in the world to master synthetic diamond technology. The successful development of synthetic diamonds has filled the gap for China and opened up a new field of research on new materials. On this basis, after more than a year of hard work and stable technology, we mastered the complete process technology of synthetic diamond. In October 1965, we trial-produced the first batch of synthetic diamonds in China and passed the ministerial appraisal. Then, the promotion of abrasive grade synthetic diamond technology was completed, and the production plants were distributed in more than ten provinces and cities nationwide, so that the abrasive grade diamonds were initially established in China, forming a prototype of the artificial diamond industry.

First, the origin of the task and the establishment of the "121" research group

Synthetic diamond is a new technology developed in the 1950s. It involves a wide range of not only mechanical equipment, but also a complete set of process technologies such as materials, physics and chemistry. It is very difficult. At that time, only a few countries, such as the United States, Sweden, and the United Kingdom, were in control of the country and imposed a technical blockade on our country. China's natural diamond resources are scarce. In the 1960s, it was mainly imported from the Soviet Union and the African Congo. In 1960, due to the breakdown of Sino-Soviet relations and the African Congo, China's natural diamond sources were cut off, and many domestic precision manufacturing and defense industries needed it. Industrial diamonds, especially precision machinery, oil extraction, metallurgy, geological exploration and electronics. At that time, Minister He Changgong of the Ministry of Geology wrote a letter to the party group of the Ministry of Machinery, proposing that the geological department should study the artificial diamonds urgently need to warm and pressure the equipment, and ask the Ministry of Machinery for assistance, and the letter was transferred to the general branch of the General Institute. In the 'double revolution' (technical innovation, technological revolution) campaign carried out by the national research institutes in 1960, our institute proposed to engage in artificial diamonds, and sent people to the Ministry to find out the opinions of the engineers of the technical department of the Department of Technology. He said: "This task has arranged a certain unit of the Academy of Sciences. They don't do it. You just do it, give you the following." In October 1960, the Department of Machines gave me the task of developing synthetic diamonds. It was officially established at the end of 1960. Organize research on this topic. At that time, I learned from the Soviet Union and returned to China. The leaders officially handed over this topic to me. Because the cutting-edge science and technology topics are extremely confidential, GM gave the title "121" (meaning the first laboratory is the second group) No.1 subject, I am in this group). At the beginning of 61, the project design task book was started, and a program discussion meeting was held with the General Office, the Abrasives, the Mechanical Institute, the Geosciences Institute, and the Department of Technology, and the meeting was hosted by General Manager Su Youquan. The preliminary plan was proposed by General Manager Hu Enliang and a division of labor was carried out:

GM: comprehensive responsibility, establishment of laboratories, equipment design and manufacturing, pressure measurement, process preparation;

Mechanical Institute: Carbide finishing (not dry), strength calculation;

Abrasives: synthetic raw materials and process preparation (purification of graphite and boron nitride), physical and chemical analysis and identification;

Geosciences: temperature measurement, pyrophyllite preparation (later arranged graphite molding);

Since the mechanical institute did not participate after one month of work, it was jointly carried out by the General Institute, the Institute of Grinding and the Institute of Geosciences. However, there were adjustments during the work process. At the beginning, GM and the Academy of Sciences often met. The participants at the time were as follows:

General Office: Lian Yuanjian, Hu Enliang, Xu Jinfeng, Zhang Yonghua, Jin Qiuye, Liu Kaizhong and Du Fuchang;

Academy of Sciences: Yao Yucheng, Xiong Wensong, Zhou Jitang, Sun Rongchuan;

Abrasives: Yu Hongchang, Wang Guangzu, Lu Feixiong, Yu Zhengmin and Li Jinbao.

Second, the successful trial of synthetic diamond

In the spring of 1961, in the absence of technical materials, no test equipment and equipment, and manpower thinness, the development of synthetic diamonds began, a white paper, able to draw the most beautiful pictures. We first investigated the situation at home and abroad, collected more than 100 foreign related literatures, and began to have a little understanding of super-compression technology and synthetic diamonds. Based on this, we carried out a program demonstration. Through analysis, we believe that we can learn from the successful experience that the predecessors have achieved, combined with the foundation of my pressure, and decided to directly apply to the 100,000 atmosphere system. More than a hundred years ago, people tried to obtain diamonds by manual methods, but they have not been successful. The main reason is that it is very difficult to build a container that can withstand 50,000-60,000 atmospheres and more than one thousand degrees of temperature. It was not until 1954 that T. Hall et al. solved this problem that diamonds were first synthesized. Therefore, the design and manufacture of ultra-pressure and temperature-sensing devices has become the primary key to our efforts to overcome this problem. Combining with our own situation, we decided to adopt the two-sided top structure device based on the principle of simple, fast and reliable. In the design, we solved the two problems of strength calculation and material selection. In the second quarter of 1961, the complete set of drawings was designed and officially named. For the '61 type super 髙 pressure 模具 mold'.

The pilot project went to the pilot plant, and the party’s general branch attached great importance to it. It was ranked No. 1 and the whole line was green. A total of 1/3 of the processing power of the whole plant was invested before and after the mold manufacturing was completed. At the same time, Comrade Yuan Jianjian was sent ( At the time, the director of the room) strengthened the leadership of the research team. The designer went to the factory to learn a lot of practical knowledge from the workers' masters. He has grown his talents and overcome many technical difficulties. For example, the finishing of hard alloy parts with a diameter of 70 mm was rarely encountered in China at the time. Machine tools, technicians and workers work together to learn, boldly modify the machine tool, quickly master the EDM technology, and solve the problem of machining of hard alloy parts. For example, for the forging and heat treatment of 45CrNiMoVA steel ring, there is no mature processing technology at that time. It is also solved by continually exploring the experience in practice and gradually mastering its forging ratio, forging temperature and better heat treatment specification. Finally, it encountered assembly difficulties. Due to the interference fit between the steel ring and the steel ring and the steel ring and the steel ring, the maximum interference is 8%, which is rare for general cold press assembly. If the press-fit procedure is incorrect or forging, heat treatment is not good, etc., it often causes the steel ring to rupture. We compared various press-fit methods, repeated trials, and spent a lot of effort on the selection of lubricants, such as lard. Lubricating materials such as engine oil and graphite powder have been tried. Later, a new lubricating material, molybdenum disulfide organic solvent (acetone or ethanol), was sprayed, and the assembly problem was solved.

The first set of '61 type super-pressure enthalpy temperature device' was born at the end of 62. The abrasives in Hongchang and Wang Guangzu also came to Beijing General Motors in the first half of 1962. They collected a large amount of foreign materials. The in-depth and detailed analysis of the synthesis process was carried out, and the selection basis and related process ideas of the thermodynamic conditions of synthetic diamond were proposed. In 1962, Comrade Yuan Yuanjian considered that the Type 61 device was too complicated and difficult to process. He designed the Type 62 device and put it into production. The Type 61 was suspended, but the final assembly test of the Type 62, the steel ring broke, and both sets were scrapped. At this time, in the first half of 1963, the task was very tight, and we had to suspend the 62-type manufacturing and analyze the cause of the failure. The 61-type mold that was originally stopped was restored. At this time, China's artificial crystal academic conference is being held in Beijing. I participated in the conference and wanted to use the Dongfeng of the conference to promote the synthetic diamond project. It is highly recommended that the synthetic diamond be listed as the second key project of the five-year plan. The host is Ge Tingjun, the director of the Institute of Silicate of the Academy of Sciences. He believes that this project is not mature internationally. He disagreed with the key project of the second five-year scientific research plan. Later, Wu Ganzhang, director of the Crystal Office of the Institute of Physics. With the help of it, it was finally listed as the 50 key projects of the second five-year Science and Technology Commission. At that time, I announced at the meeting: In 1963, synthetic diamonds must be synthesized! After the meeting, the State Science and Technology Commission allocated 300,000 yuan to GM for the special research project of synthetic diamond.

At this time, the 61 type ultra-high pressure temperature mold has been manufactured. Can it meet the design requirements? First of all, to solve the ultra-pressure test technology, this project is under the responsibility of GM's Xu Jinfeng. We refer to the common pressure measurement method introduced by foreign materials, and indirectly measure the pressure by using the resistance changes caused by the phase transformation of the four elements Bi, Tl, Cs and Ba under a certain pressure. Since the original resistance of these samples is small (in a few percent to a few tens of ohms) and the resistance changes less, the effect of contact resistance is minimized, which is the key to measurement success. . After repeated trials, find the cause from the failure, and finally use amalgam to increase the contact surface at both ends of the sample, so that the contact surface is very stable during the pressure process, thus ensuring the reliability and accuracy of the measurement. , 铋, 铊, 铯 have successfully measured the data, initially measured the accuracy of the press load pressure curve of +4%, at this time, the defect has not been measured. The measurement of temperature is carried out by Yao Yucheng and Xiong Wensong of the Institute of Geosciences. They use indirect heating method to form a spiral small groove on the outer wall of the pyrophyllite tube, which is heated by platinum wire. They do it on the simulation equipment first. A large amount of experimental preparation work, especially in the selection and exploration of the performance and processing methods of pyrophyllite, they successfully measured the indirect heating power-temperature curve on the Type 61 device. Due to the small volume of the test chamber of the Type 61 device, it is difficult to use indirect heating, and the operation and assembly are also cumbersome. Therefore, we have considered the direct heating scheme, but in the end, the temperature is measured at low pressure, and the measured data is analogized. Is it measured under pressure from synthetic pressure or under the pressure of synthetic diamond? We found that the measured data under normal pressure and the measured data under the pressure are very different, and it is not feasible at all. The power-temperature relationship must be measured under synthetic pressure. Zhang Yonghua and Liu Kaizhong, who are responsible for the temperature measurement work, carefully assembled the samples and carefully operated the press. After dozens of tests, the assembly method was repeatedly improved, and the mica sheet was used as a liner to solve the problem-measured power-temperature curve. At the same time, the Academy of Sciences and the Institute of Abrasives also measured the power-temperature curve by directly heating the sample.

"Man proposes, God disposes". In the second half of 1963, the Type 61 device was successful, and the power-temperature curve was also measured. At this time, it was urgent to determine the process plan. From the relevant reports, we learned that the Soviet Academy of Sciences successfully synthesized synthetic diamonds in 1961 and awarded the Red Flag Medal to the researchers. In 1962, Komatsu, Japan also successfully synthesized synthetic diamonds, which provided some new ideas for our synthetic scheme. Our three partners met to discuss the plan. I proposed using a sheet-like overlapping assembly block. For the catalyst abrasive, pure nickel was proposed. GM Akio proposed the use of alloys, and finally decided to use nickel or alloy, sheet-like overlapping assembly blocks. At that time, the alloy was made of NiCr electric furnace wire, flattened with a forging hammer and then punched into pieces, assembled with graphite sheets, and assembled with pure nickel sheets and graphite sheets for abrasives. Yao Yucheng of the Academy of Sciences also prepared several sets of assembly parts. From the fourth quarter of 63, the synthetic test was officially started. After more than 50 process tests, no diamond has been found, but the managerial identification has been accompanied by the formation of diamonds such as Ni3C, indicating that the synthesis temperature and pressure are close to the stable zone of diamond. Analysis of the two factors of temperature and pressure, the distribution of temperature on the test bar is very uneven, that is, there is a large temperature range, the key is to raise the pressure to meet the growth conditions of synthetic diamond. At this time, the pressure curve is always unable to get the test result. The general manager Su Youquan proposed that the stroke may not be enough, so the stroke is increased. On December 5, 1963, the pressure curve of the helium was successfully measured. The curves have been obtained, everything is ready, only the east wind.

I decided to formally carry out the synthetic test on December 6th. I carried out a total of 4 times. On the same day, I used the abrasive material in Hongchang to take a synthetic sample back to Zhengzhou for analysis. On the evening of the 10th, I received a telegram from Yu Hongchang, which was already 9:00 pm. Together with Tang Yujing, I went to the Tianqiao Post Office to find an interpreter. When we saw the translated message "I found a D-line spectrum", we were very excited. The hard work of three years finally saw the dawn! The next day, I told the leader the good news, and I did several experiments. I personally sent it to Zhengzhou Abrasives for analysis. A few days later, Yao Yucheng from the Academy of Sciences came to look for them. They also prepared a few samples. They must try. We promised to reassemble the 62 molds and let them try. The results also succeeded in pressing out the diamonds. It is the Institute of Science and Technology. analysis. We tested a total of eight times before and after, four of which had diamonds and the largest one was 0.7mm. On December 30th, we sent the official report to the Ministry of Machinery and the State Science and Technology Commission. In 1964, the Chinese Academy of Sciences opened its annual meeting in Xiangshan. Dean Zhang Jinfu spoke at the meeting. "The Department of Synthetic Diamond has been made out, and our Academy of Sciences is out of date!" In fact, according to the research at the time, the Institute of Physical Physics, He Shou'an and Shen Zongtong could all be made before us. Later, they took the preserved 63-year sample for analysis and found that there was diamond. At the beginning of 1964, our research team won the first-class scientific research achievement award of the State Science and Technology Commission.

Third, to win the pursuit, to overcome the synthetic process, the top hammer life

The successful development of synthetic diamonds is a welcome step in scientific experiments, which has led us to break the superstition of synthetic diamond synthesis technology. There were two opinions before us: one opinion that our mission has been completed, the cooperation of the three units has ended, the next step should be handed over to other units to engage in the relay race; the other opinion is that We continued to stabilize the process and increase production on the basis of the Type 61 device, and promoted it to production. We adhered to the latter opinion and received the support of the leaders of the institute. We decided to explore a complete set of synthetic process methods on the Type 61 device and promote production as soon as possible. We will provide a batch of diamond abrasives for the country before the trial of the six-face top. We analyzed the promotion of production on the Type 61 device, and must solve the 'three lows' (low success rate, low conversion rate, low top hammer life), which essentially solves the two key factors of the synthesis process and the top hammer life. First of all, we must improve the synthesis process, improve the synthesis success rate and conversion rate. At that time, the conversion rate was only 1%, and the yield was only 0.01 carats per time. Therefore, we must work hard on the synthesis process. Practice has proved that under certain pressure and temperature conditions, the catalytic material has a great influence on synthetic diamond. Can we find a better catalyst material than NiCr alloy? We have selected more than ten kinds of materials based on the Bajia metal. The alloy has been tested for nearly 200 times. The results show that the Ni Cr Fe alloy is better, and the success rate and conversion rate have been improved, but it has not reached the expected target. (Part of the index: conversion rate 20% -25 %), the difficulty is still very big. Through summarizing work, careful observation and analysis, why do the catalysts of the same material have long diamonds, while others cannot grow diamonds. In the case of not being able to grow diamonds, alloys and graphites do not interact to form so-called light panels. Through analysis, we realized that in addition to the effects of temperature and pressure, there is also a problem of the activity of the catalyst surface. When we removed the surface oxide scale of the alloy with acid treatment, there was a white film on the surface, and the film was scraped off with a knife. The test effect was good, which proved that the film was a harmful substance. We rinse the surface of the acid-treated alloy with distilled water and wash away the acid ions on the surface of the residual alloy. By this method, the synthesis success rate can reach 100% (this becomes the later rolling alloy and The basis of a set of process conditions such as acid treatment and ball milling surface). On the basis of improving the synthesis success rate, the reasonable assembly form is selected, the longitudinal temperature gradient is reduced, the graphite material which is favorable for diamond growth is selected, and the contact surface between the alloy and the graphite sheet is increased to achieve a conversion rate of 24%. Although the synthesis success rate and conversion rate have been greatly improved, the single production still fails to meet the production requirements. The distribution of temperature in the test chamber is analyzed through experiments, and the method of gradually expanding the test cavity is adopted. It proves that expanding the test bar to 5mm has little effect on the life of the pressure cylinder, but the synthetic output is several times higher. The single production reaches 0.65 carats and the last one can reach 1 carat. This is 200 tons of two sides. The top device promotes production and lays a solid foundation.

After a series of efforts, the synthesis test basically stabilized the process, but the problem that the top hammer life was too short, sometimes three hammers were broken in one day. The cost of each dome hammer was 300 yuan, and the processing was very difficult (at the time there was no Diamond grinding wheel), which is not feasible in terms of processing capacity and economic accounting. So what is the key to affecting the service life of the top hammer? The analysis of the top hammer rupture phenomenon is half-opening or partial fragmentation, which makes us realize that the main material and sintering process cause the top hammer to rupture. The reason is that the upper and lower top hammers are not well aligned, and the local conical surface is too strong. Therefore, we will work hard from the operation to improve the guiding precision and reduce the tonnage of the press, so that the cone surface is evenly stressed and the cone force is reduced. The press tonnage has been reduced from 170T to 160T. Through a large number of tests, the life of the top hammer has been raised from 29 times to 150 times and 315 times. The solution of the single synthetic output and the life of the top hammer greatly reduced the cost of synthetic diamond, and the technical and economic indicators basically met the requirements for promotion and commissioning.

4. Through the ministerial appraisal, the abrasive grade synthetic diamond is promoted and produced.

Under the auspices of the Department of Science and Technology of the Ministry of Science and Technology, on October 27, 1965, the abrasive grade human diamond review and appraisal meeting was held in the General Office Building. Comrade Hu Enliang represented the research team and made a report on the results of the "synthetic diamond test". The committee unanimously agreed to the test report. The technical appraisal book states:

“Experimental research work on synthetic diamond abrasive grades, under the care and support of the State Science and Technology Commission, is based on GM, in the Abrasive Institute, the 746 Factory of the Ministry of Geometry, the Department of Geology of the Ministry of Geology, the 601 Factory of the Ministry of Metallurgy, and the Materials Office. Under the vigorous cooperation and joint efforts of the Electrical and Electronic Research Institute and other units, after repeated trials and continuous improvement in April 1961, the synthesis process of the two sides was basically stable in October 1965, reaching the Department (65) The requirements specified in the text No. 736. The appraisal committee agreed that:

1. The synthetic process is basically stable and has reached and exceeded the technical indicators issued by the Ministry:

(1) The average conversion rate is 24% (20 to 25% of the specified index). The average synthetic diamond is 0.65 carats per synthetic test;
(2) Synthetic diamond particle size below 200 microns, in line with general abrasive requirements;
(3) 480 carats of diamonds have been obtained from January to October this year;
(4) The average life of the upper and lower top hammers of cemented carbide molds is more than 150 times, and the average pressure cylinders are more than 250 times (specified 100 times)

2, the cost per carat of synthetic diamond abrasive is less than 10 yuan, lower than the import price.

3. The above situation shows that the synthetic process of synthetic diamond abrasive on both sides has already been put into industrial production conditions, and it is recommended that the relevant departments arrange production.” The State Science and Technology Commission officially published it in the same year (only the key issues of the State Science and Technology Commission, after the ministerial appraisal and finalization, The Science and Technology Commission only published it.) After the appraisal meeting, many units came to study in our school. We organized the “Ulan Muqi”-style promotion detachment and went deep into the factory. It took less than a month, December 26, 1965. The company helped Changchun Automobile Factory's tool factory to trial and manufacture artificial diamonds and put them into small batch production, which solved the key problems for the diamond grinding wheels required for the tool's hard alloying. Then it promoted technology and blossomed in more than ten provinces and cities nationwide. Among them, Mudanjiang 121 Factory, Harbin Grinding Wheel Factory, Shanghai Grinding Wheel Factory, Suzhou Grinding Wheel Factory, Shanghai Watch Factory, Shanghai Watch Table Component Factory, Beijing Grinding Wheel Factory, Shenyang Liming Machine Factory, Tianjin Grinding Wheel Factory, Xi'an Qing'an Company, Zhengzhou Ersha, The Qingdao Cemented Carbide Research Institute and other units were officially put into operation in 1966-1967.

V. Preliminary design of China's synthetic diamond industrial production equipment

In 1962, I began to consider the production equipment of synthetic diamond industry. I collected a document and wrote a paper. I proposed that the hinged six-face press is an industrial production equipment suitable for synthetic diamond. In 1963, I began designing 6x300 tons and 6x600 tons. Pressing machine drawings, in June 1964, according to the instructions of the superior, I handed over the drawings to the Jinan clinic. I stayed at the institute for a week and made a technical presentation. They received me the chief engineer and the laboratories. Director and project leader Lu Naiqi, they made a lot of changes on this basis, and continued to improve the final design, but the original original design of the six-sided top press in China should still be me. After nearly 50 years of continuous improvement and development, the six-face press has become the most important production equipment in China's synthetic diamond industry, and has made significant contributions to the development of China's synthetic diamond industry.

In the early 1960s (1961-1965), I wrote a total of 35 design test reports, accumulating all the technical materials related to the trial production of synthetic diamonds at that time. This scientific achievement was awarded the major results of the National Science Conference in 1978. Later, I continued to study synthetic diamonds. In 1984, I attended the second hard material science conference in Rhode Island, Greece. The papers I published at the conference were well received by the participants and received the conference. Proceedings. In this paper, I put forward the idea of ​​"potential gradient", which proved to be correct through years of practice. The potential gradient can not only improve the grade of the diamond, but also greatly improve the life of the top hammer and greatly reduce the production cost. (See: The Problem of electronic transition in the conversion of graphite into diamond, Science of hard Materials 75Vol.1985)

China's first synthetic diamond has been successfully developed for 50 years. In the past 50 years, China's synthetic diamond industry has flourished and achieved brilliant achievements. China's synthetic diamond production has exceeded 10 billion carats in 2012, making it the largest producer in the world. As a veteran of the super-hard materials industry, I am very pleased with this, but we should still clearly see that the varieties, quality and application fields of our products are still far from the developed countries, and there is still a long way to go. I sincerely hope that China's synthetic diamond industry will continue to do a good job and benefit all mankind! (Excerpted from the "Fifty Years of China's Superhard Materials Industry", "Recalling the Past and the Years of Thickness - Commemorating the 50th Anniversary of the Birth of Chinese Diamonds")

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