High-strength pressure vessel, method for manufacturing a high-strength pressure vessel, and applications of the high-strength pressure vessel as a high-pressure reaction vessel and high-pressure storage vessel.

Abstract

The present invention provides a double-tube connection structure for detonation synthesis, a detonation synthesis apparatus, and its use. The double-tube connection structure for detonation synthesis comprises a drive tube 4, a sample tube 2, a fixed assembly, and an end plug 7 installed at the end of the sample tube. The drive tube is mounted around the outside of the sample tube, a cavity 3 is formed between the drive tube, the sample tube, and the end plug, and the fixed assembly is installed at both ends of the drive tube and the sample tube. After detonation, the detonation wave propagates from top to bottom, and due to the action of the detonation wave, the drive tube converges and slides toward the sample tube, covering the outside of the top end plug of the sample tube, the sample tube, and the bottom end plug of the sample tube. The detonation synthesis apparatus comprises the above-described double-tube connection structure for detonation synthesis. [Effects] This device can effectively convert graphite samples into high-purity polycrystalline diamond. Furthermore, the high-purity polycrystalline diamond obtained through this conversion can be completely recovered.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of new material synthesis, and specifically relates to a double-tube connection structure for detonation synthesis, a detonation synthesis device, the use of the double-tube connection structure for detonation synthesis, a method for manufacturing a high-strength composite tube, a method for manufacturing diamond, and the use in the manufacture of a high-strength composite tube and / or a high-strength pressure vessel of a detonation synthesis device.

Background Art

[0002] Diamond is a rare multifunctional material and is currently the hardest among naturally existing substances. Also, as the most ideal superhard material, it is widely applied to many conventional industries such as machinery, geology, transportation, building materials, petroleum, etc., significantly improving production efficiency and promoting the generational change of conventional industries.

[0003] Currently, diamond micropowder and products are widely applied to fields such as automobiles, machinery, tools, electronics, integrated circuits, mobile phones, aviation, space, optical devices, glass, ceramics, petroleum, geology, sapphire, chips, medicine, electronic information communication, etc.

[0004] Diamond has an extremely small reserve on the earth, exists deep underground, and is difficult to mine, so it cannot meet the requirements of the rapid development of industries and science and technology. For this reason, scientific research has been carried out to artificially synthesize diamond by spending a lot of human and material resources, and as a result, two methods for artificially synthesizing diamond have been discovered. The first is the static pressure method that uses high-temperature and high-pressure mechanical equipment to convert graphite into single-crystal diamond by phase transition. Currently, this technology is mature and widespread, but when using this method, the cost of equipment is relatively high, the raw materials are complex, and the particle size of the produced products is on the order of mm.

[0005] The second method is an impact synthesis method that uses explosives to create high-pressure, high-temperature conditions, converting graphite into polycrystalline diamond with a particle size on the order of micrometers within a time frame on the order of microseconds. Impact synthesis technology is a new technique for synthesizing new materials without requiring large and expensive machinery. Currently, a few companies, such as DuPont in the United States, have fully grasped this technology and are achieving mass production.

[0006] Polycrystalline diamond differs from single-crystal diamond in many ways, not only in crystal structure and grain size, but also in performance. Polycrystalline diamond offers superior grinding performance and can be applied to high-precision, high-quality technologies such as aerospace, fine ceramics, LED chips, and sapphire substrates. Furthermore, polycrystalline diamond possesses other excellent properties and is expected to be used in defense and civilian applications.

[0007] Diamond and graphite are allotropes of carbon, and it is easy to conceive that graphite can be used as a raw material for the artificial synthesis of diamond. Figure 1 is a pressure-temperature phase diagram of carbon, which is a multi-component phase diagram. The phase diagram shows the temperature and pressure regions in which graphite and diamond exist stably. In the diamond-stable region, where the pressure is relatively high, the graphite crystal structure is unstable, and graphite is converted to diamond in order to reduce its free energy. Also, in the graphite-stable region, where the pressure is relatively low, the polycrystalline structure of diamond is unstable, and polycrystalline diamond is converted to graphite in order to reduce its energy. As can be seen from such a multi-component phase diagram of carbon, in order to synthesize diamond by explosive shock, at least the following requirements must be met.

[0008] (1) It is necessary to develop a suitable detonation device that creates the specific high temperature and high pressure conditions required to convert graphite into diamond.

[0009] (2) Even after rapid detonation and transition to room temperature and pressure, it is necessary to maintain the diamond phase that exists under high temperature and pressure and prevent graphitization.

[0010] (3) Because the explosion is a difficult process to control, technical challenges related to diamond recovery need to be addressed.

[0011] The main technical challenges of conventional methods are synthesizing high-purity polycrystalline diamonds under high pressure caused by impact, improving the conversion and recovery rates of the diamonds, and achieving mass production while maximizing cost reduction. [Overview of the project]

[0012] The technical problem that this disclosure aims to solve is the low conversion rate and difficulty in recovery in conventional diamond synthesis processes using detonation. This disclosure provides a double-tube connection structure for detonation synthesis, a detonation synthesis apparatus, and its use that can solve the above problem.

[0013] This disclosure will be realized by the following technical proposal.

[0014] The double-tube connection structure for detonation synthesis comprises a drive tube, a sample tube, and end plugs installed at both ends of the sample tube. The drive tube is mounted around the outside of the sample tube, and a cavity is formed between the drive tube, the sample tube, and the end plugs. The double-tube connection structure for detonation synthesis further comprises a fixed assembly, which covers the top and bottom ends of the drive tube, respectively. After the explosive is detonated at the top, the detonation wave propagates sequentially from top to bottom, and the impact action causes the drive tube to converge and slide from top to bottom toward the axis of the sample tube, and the drive tube sequentially covers the outside of the top end plug of the sample tube, the sample tube, and the bottom end plug of the sample tube from top to bottom.

[0015] Let's take the synthesis of diamond by detonation shock as an example. Diamond synthesis by detonation shock involves applying a strong shock wave to a mixture of graphite and copper powder, and the instantaneous action of thousands of degrees Celsius temperature and hundreds of thousands of atmospheres of pressure caused by the strong shock wave converts the graphite into diamond. Because this instantaneous, violent explosion is completed within tens to hundreds of microseconds, high-pressure shock synthesis is difficult to control, the sealed end plugs at the ends of the sample tubes are prone to rupturing due to the explosion, causing the sample to scatter, resulting in a low conversion rate and making recovery extremely difficult.

[0016] According to the double-tube connection structure between the sample tube and the drive tube described herein, aggregate sliding and plastic deformation occur at the end of the drive tube, firmly covering the end plug. This effectively prevents the bursting of the sealing end plug at the end of the sample tube, contributing to improved conversion and recovery rates.

[0017] Therefore, the drive tube according to this disclosure can primarily achieve the following two functions: (1) To absorb the energy of the explosive, it transfers energy to the sample when the sample tube is struck, creating high-temperature and high-pressure conditions for converting graphite into diamond. (2) After the explosion, the drive tube flies through the cavity and collides at high speed with the end plugs and sample tube, and the collision pressure between the drive tube, end plugs and sample tube greatly exceeds the Hugoniot elastic limit of the drive tube material, causing the material to enter the plastic region. Due to the accumulation effect and plastic deformation, the drive tube tightly covers the sample tube and the sealed end plugs at both ends. This prevents the end plugs from flying out, and the raw sample is completely sealed inside the sample tube. In this case, the drive tube, sample tube and sealed end plugs at both ends form a highly strong composite tube due to the detonation strengthening effect, forming a complete container for collecting the diamond sample. This makes it possible to completely seal a sample that reaches pressures of 20 GPa or more and high temperatures of several thousand degrees upon impact.

[0018] Furthermore, in the axial direction of the sample tube, circumferential cavities are formed at equal intervals between the inner wall of the drive tube and the outer wall of the sample tube. In this disclosure, there are no obstacles between the drive tube and the sample tube, ensuring uniform propagation of the detonation wave. This makes it possible to create high-temperature, high-pressure synthesis conditions, allowing the drive tubes to converge, slide, and plastically deform, and securely cover the sample tube and end plug externally to form a composite tube with both ends sealed.

[0019] Furthermore, the outer diameter of the portion of the end plug that the drive tube covers and contacts is smaller than the outer diameter of the sample tube.

[0020] A preferred approach is to install the drive tube so that the outer diameter of the end plug portion that it covers and contacts is smaller than the outer diameter of the sample tube. In this case, when the drive tube moves in conjunction with the axis of the end plug due to high-pressure detonation products, the diameter of the drive tube after contraction at the small diameter of the end plug will be smaller than the diameter of the drive tube after contraction at the sample tube. As a result, the drive tube will be formed as an end-port contraction structure, further improving the tightening effect on the end plug.

[0021] Furthermore, the end plug has a tapered structure, and the larger diameter end of the tapered structure connects to the sample tube.

[0022] By installing the end plug in a tapered structure, the tightening action on the end plug of the drive pipe can be improved, and this can also contribute to the peaceful downward propagation of the detonation wave.

[0023] Furthermore, after detonation, as the detonation wave propagates to the connection point between the end of the drive pipe and the fixed assembly, the connection at that point is released, and the fixed assembly is ejected outward by the tensile wave action.

[0024] As can be seen from detonation physics, in air, in the case of a columnar propaganda charge, when detonated on a plane at one end, the ratio of the mass (M1) and energy (E1) propagating in the direction of motion of the detonation wave to the mass (M2) and energy (E2) propagating in the opposite direction of the direction of motion of the detonation wave is M1 / M2 = 4 / 5 and E1 / E2 = 16 / 11. When the high-pressure detonation product expands to disperse into the air at the ends of the device, i.e., the top and bottom ends of the sample tube, a tensile force (impact momentum) is generated at the end opening. When this becomes sufficiently large, the opening at the end of the sample tube may rupture, causing the sample inside the tube to be discharged and leak. To avoid tensile stress at the ends, fixed assemblies are installed at both ends of the sample tube and the drive tube. In this case, when the fixed assembly receives kinetic energy, it will fly out and release the kinetic energy. This prevents pulling on the end of the sample tube, effectively prevents the tube opening at the end of the collection container from bursting, and achieves the goal of completely recovering the sample.

[0025] Furthermore, a fixing assembly attached to the top of the drive tube includes a fixing ring and at least one cover plate, one end of which is connected to the top of the drive tube and the other end of which is connected to the cover plate, the cover plate being for sealing the cavity, and a fixing assembly attached to the bottom of the drive tube includes a fixing ring and a base, one end of which is connected to the bottom of the drive tube and the other end of which is connected to the base, the base being for fixing and support.

[0026] The cover plate relating to this disclosure is for fixing the sample tube, drive tube, and fixing ring, and for sealing the top opening of the cavity between the sample tube and the drive tube to prevent explosives from entering the cavity. The base is for fixing and supporting the drive tube and the sample tube.

[0027] Furthermore, the end of the drive pipe and the end of the fixing ring are connected by a joint to form a coaxial cylindrical structure.

[0028] In the present disclosure, by joining the drive tube and the fixed ring, it is possible to ensure that the fixed ring smoothly pops out and releases kinetic energy during the detonation process, while maximizing the simplification of the structure and reducing costs.

[0029] Furthermore, a position-limiting ring I extending axially outward is installed on the bottom end face or the top end face of the drive tube, and a position-limiting ring II extending axially outward is installed on the end face of the corresponding fixed ring. The connection between the drive tube and the fixed ring is realized by the circumferential installation of the position-limiting ring I and the position-limiting ring II.

[0030] This simplifies the connection structure between the drive tube and the fixed ring, which is beneficial for reducing the manufacturing cost and the mounting cost. Also, when the end of the drive tube gathers and moves under the action of high-pressure detonation products, no resistance will occur at the connection site between the fixed ring and the drive tube.

[0031] Furthermore, the fixed assembly further includes a fixed block, the fixed block is installed inside the fixed ring, one end of the fixed block is connected to the end plug, and the other end of the fixed block is connected to the cover plate or the base.

[0032] If the fixed blocks and the fixed rings are installed at both ends of both the sample tube and the drive tube, after receiving the kinetic energy, these blocks and rings will pop out outward and release the kinetic energy. In this way, the end of the recovery container can be effectively protected, contributing to the complete recovery of the sample. In order to release as much kinetic energy as possible and protect the end of the sample tube, the weights of the fixed ring and the fixed block are increased, for example, a metal ring structure or a metal block structure is adopted.

[0033] This disclosure further discloses a detonation synthesis apparatus. The detonation synthesis apparatus comprises a housing and the above-mentioned double-tube connection structure for detonation synthesis installed within the housing, wherein a main explosive is filled in a cavity between the inner wall of the housing and the outer wall of the drive tube, the bottom ends of both the drive tube and the sample tube are attached to a support plate by a fixed assembly, the support plate is for sealing the bottom end of the housing, and a detonator is installed at the top end of the housing.

[0034] This disclosure provides a double-tube shock synthesis apparatus for columnar sliding detonation. After detonation at the top of the apparatus, a detonation wave is formed, and the detonation wave propagates from top to bottom along the outer wall of the drive tube at a stable speed. Due to the action of high-pressure detonation products behind the detonation wavefront, the drive tube converges and slides toward the axis of the apparatus. As it flies through the cavity, at the interface between the explosive and the drive tube, the interaction of compression waves and rarefied waves causes the drive tube to continuously gain energy from the explosive and accelerate, so that the drive tube converges toward the axis. Due to the convergence effect, the speed of its free surface also increases. After the drive tube collides with the sample tube at high speed, a stable detonation shock wave system is formed within the sample, and the shock wave passes through the entire sample from top to bottom. As a result, the sample is uniformly compressed. Therefore, according to this disclosure, the conversion rate can be very high, reaching more than 90%, and 100% recovery can be achieved.

[0035] Furthermore, the detonation component includes an explosive, a detonator fixing plate, and a detonator, wherein the explosive is laid on top of the main explosive, the detonator fixing plate is placed on the explosive, and the detonator is fixed to the detonator fixing plate.

[0036] The above-described double-tube connection structure for detonation synthesis or the above-described detonation synthesis apparatus can be used to convert a low-pressure phase material into a high-pressure phase material, or to pulverize a hard material, wherein the high-pressure phase material includes diamond, carbides, nitrides, and borides.

[0037] This disclosure further provides high-strength composite tubes. The high-strength composite tubes are manufactured using the double-tube connection structure for detonation synthesis described above or the detonation synthesis apparatus described above.

[0038] This disclosure further provides a high-strength pressure vessel. The high-strength pressure vessel is manufactured using the double-pipe connection structure for detonation synthesis described above or the detonation synthesis apparatus described above.

[0039] This disclosure further provides a method for manufacturing the above-described high-strength composite tube or high-strength pressure vessel. The high-strength composite tube or high-strength pressure vessel is manufactured using the above-described double-tube connection structure for detonation synthesis or the above-described detonation synthesis apparatus.

[0040] The high pressure, high temperature, and high strain rate generated by explosion and impact action constitute a comprehensive means of acting on materials and have the potential for a wide range of applications. The above-described apparatus can be widely used not only for the synthesis of diamond but also for the development of other new materials. For example, it may be used for the synthesis of wurtzite-type boron nitride and sphalerite-type boron nitride, which have lower hardness than diamond, and for the synthesis of constituent ceramics of carbides, borides, and nitrides such as TiC, TiB2, B4C, and SiC. These are lightweight and high-temperature resistant constituent ceramics that high-tech companies are looking for. It may also be used for grinding ultrahard materials such as diamond, which are normally difficult to grind, making it suitable for a variety of applications.

[0041] This disclosure has the following advantages and beneficial effects.

[0042] 1. According to the connection structure between the sample tube and the drive tube of this disclosure, collective sliding and plastic deformation occur at the end of the drive tube, firmly covering the end plug. This effectively prevents the bursting of the sealing end plug at the end of the sample tube, contributing to improved conversion and recovery rates. Therefore, the drive tube according to this disclosure can primarily achieve the following two functions.

[0043] (1) As a means of absorbing the energy of the explosive, when the sample tube is struck, the energy is transferred to the sample, creating high temperature and high pressure conditions for converting graphite into diamond. (2) After the explosion, the drive tube flies through the cavity and collides at high speed with the end plugs and sample tube. The collision pressure between the drive tube, end plugs, and sample tube greatly exceeds the Hugoniot elastic limit of the drive tube material, causing the material to enter the plastic region. Due to the accumulation effect and plastic deformation, the drive tube tightly seals the sample tube and the sealed end plugs at both ends. This prevents the end plugs from flying out, completely seals the raw material sample inside the sample tube, and promotes the complete reaction of the raw material sample. In this case, the drive tube, sample tube, and sealed end plugs at both ends form a highly strong composite tube due to the detonation strengthening effect, forming a container for collecting the diamond sample. This allows for the complete sealing of the sample, which reaches pressures of 20 GPa or more and temperatures of several thousand degrees upon impact.

[0044] 2. The installation of the present disclosure can release kinetic energy and contribute to preventing the end of the sample tube from rupturing. When high-pressure detonation products expand at the end of the apparatus so as to disperse into the air, a tensile force (impact momentum) is generated at the end opening. When this becomes sufficiently large, the opening at the end of the sample tube may rupture, causing the sample inside the tube to be discharged and leaked. To avoid tensile stress on the end, fixing rings and fixing blocks are installed at the top and / or bottom ends of both the sample tube and the drive tube. In this case, when the fixing rings and fixing blocks receive kinetic energy, they will spring out and release the kinetic energy. This prevents tensile stress on the end of the sample tube, effectively prevents the end of the recovery container from rupturing, and achieves the objective of completely recovering the sample.

[0045] 3. The installation of the fixing ring and fixing block according to this disclosure can contribute to the stable propagation of detonation waves to the sample tube. When the explosive is just detonated, there is a detonation state that transitions from unstable to stable, so by installing the fixing block and fixing ring at an appropriate height at the top, it is possible to avoid the unstable detonation caused by the explosive.

[0046] The synthesis of diamond by detonation involves applying a strong shock wave to a mixture of graphite and copper powder, and using the instantaneous action of thousands of degrees Celsius temperature and hundreds of thousands of atmospheres of pressure caused by the strong shock wave to convert the graphite into diamond. By using copper powder as a quenching material, the diamond phase, which is stable under high temperature and high pressure, can be preserved under low temperature and low pressure. This disclosure makes this instantaneous, violent explosion controllable and adjustable according to the user's requirements.

[0047] This disclosure is important for breaking the technological blockade and realizing the mass production of polycrystalline diamond. Explosive or shock wave synthesis of new materials is an important new technique in materials research, and this new technique is expected to have a wide range of applications. The inventors, through many years of research on detonation shock waves, have grasped the intrinsic laws of the mechanism of the phase transition from graphite to diamond by shock, based on deep theoretical knowledge and extensive experimental experience, and have invented this apparatus. The apparatus according to this disclosure can create high temperature and high pressure conditions for the conversion of graphite to diamond, and can uniformly compress the sample graphite within the apparatus to convert it into high-purity polycrystalline diamond. The conversion rate can be significantly improved to more than 90%, and the high-purity polycrystalline diamond obtained by the conversion can be completely recovered. The apparatus according to this disclosure can recover 100% of the diamond, enabling mass production. [Brief explanation of the drawing]

[0048] The drawings described herein are part of this disclosure and are intended solely to further illustrate the embodiments of this disclosure, and are not intended to limit the embodiments of this disclosure. [Figure 1] This is a pressure-temperature phase diagram of carbon. In Figure 1, the solid line represents the graphite-diamond phase equilibrium line, the dashed line represents the diamond melting curve, and the dotted line represents the graphite melting curve. [Figure 2] This is a schematic diagram of the detonation synthesis apparatus related to this disclosure. [Modes for carrying out the invention]

[0049] To further clarify the purpose, technical proposal and merits of this disclosure, the following descriptions will be made in more detail with reference to examples and drawings. The exemplary embodiments and descriptions of this disclosure are for interpretation purposes only and do not limit the disclosure.

[0050] Example 1 This embodiment provides a double-tube connection structure for detonation synthesis. The double-tube connection structure for detonation synthesis comprises a drive tube 4 and a sample tube 2. Both the drive tube 4 and the sample tube 2 are circular tube structures. The drive tube 4 is coaxially mounted around the outside of the sample tube 2, and a circumferential gap between the inner wall of the drive tube 4 and the outer wall of the sample tube 2 is formed as a cavity 3. Sealing plugs 7 are installed at the top and bottom ends of the sample tube 2, and both the top and bottom ends of the sample tube 2 are located inside the drive tube 4. The double-tube connection structure for detonation synthesis further comprises a fixed assembly, and the top and bottom ends of the drive tube 4 are covered with a fixed assembly that can prevent the main explosive from entering the cavity 3. After detonation, the detonation wave propagates sequentially from top to bottom, and due to the impact, the drive tube 4 converges and slides (deforms) toward the axis of the sample tube 2 from top to bottom, covering the top end plug 7 of the sample tube 2, the sample tube 2, and the outside of the bottom end plug 7 of the sample tube 2, in order from top to bottom. This forms a composite tube that functions as a complete recovery container.

[0051] Example 2 Example 2 is a further improvement based on Example 1. The outer diameter of the portion of the end plug 7 that is covered and in contact with the drive pipe 4 is smaller than the outer diameter of the sample pipe 2. More preferably, the end plug 7 has a frustoconical structure, with the larger diameter end of the frustoconical structure being inserted into the end opening of the sample pipe 2, and the smaller diameter end of the frustoconical structure being connected to the fixed assembly.

[0052] Example 3 Embodiment 3 is a further improvement based on Embodiment 1 or Embodiment 2. The fixed assembly is configured such that, after detonation, when the detonation wave propagates to the connection point between the end of the drive tube 4 and the fixed assembly, the connection point between the end of the drive tube 4 and the fixed assembly is released, the fixed assembly receives momentum and flies out, and the end of the drive tube 4 converges toward the axis of the sample tube 2 and slides to cover the end plug 7. Preferably, the fixed assembly attached to the top of the drive tube 4 includes a fixed ring 9 and a two-layer cover plate 10. One end of the fixed ring 9 is connected to the top of the drive tube 4, and the other end is connected to the cover plate 10. The cover plate 10 is for sealing the cavity 3 and has an annular groove on its lower surface, allowing the end of the fixed ring 9 to be fitted into the annular groove and fixed. The fixed assembly attached to the bottom of the drive tube 4 includes a fixed ring 9 and a base 11. The fixing ring 9 is connected at one end to the bottom of the drive pipe 4 and at the other end to the base 11. The base 11 serves as a support.

[0053] The structure for connecting the drive pipe 4 and the fixing ring 9 is as follows: The end of the drive pipe 4 and the end of the fixing ring 9 are connected by a joint to form a coaxial cylindrical structure. Specifically, the structure for connecting the top of the drive pipe 4 to the fixing assembly is such that an inner position-restricting ring is installed on the inside of the end face of the drive pipe 4, extending outward along the axial direction, and an outer position-restricting ring is installed on the outside of the end face of the fixing ring 9, with the outer position-restricting ring being fitted around the outside of the inner position-restricting ring, the end face of the inner position-restricting ring contacting the end face of the fixing ring 9, and the end face of the outer position-restricting ring contacting the end face of the drive pipe 4. The structure connecting the bottom of the drive pipe 4 to the fixed assembly is such that an outer position-restricting ring extending outward in the axial direction is installed on the outside of the end face of the drive pipe 4, and an inner position-restricting ring extending outward in the axial direction is installed on the inside of the end face of the fixed ring 9, the outer position-restricting ring is fitted around the outside of the inner position-restricting ring, the end face of the inner position-restricting ring abuts against the end face of the drive pipe 4, and the end face of the outer position-restricting ring abuts against the end face of the fixed ring 9.

[0054] More preferably, as shown in Figure 2, the system further includes a fixing block 8, the fixing block 8 being located inside the fixing ring 9, one end of the fixing block 8 being connected to the end plug 7, and the other end of the fixing block 8 being connected to the cover plate 10. Both the fixing block 8 and the fixing ring 9 are made of metal.

[0055] Example 4 This embodiment provides a detonation synthesis apparatus. The detonation synthesis apparatus comprises a housing 13, in which the double-tube connection structure for detonation synthesis according to Embodiment 3 is installed inside the housing 13, and the main explosive is filled in the cavity between the inner wall of the housing 13 and the outer wall of the drive tube 4. A fixing assembly installed at the top of both the sample tube 2 and the drive tube 4 consists of a fixing ring 9, a fixing block 8, and a cover plate 10, and a fixing assembly installed at the bottom of both the sample tube 2 and the drive tube 4 consists of a fixing ring 9, a fixing block 8, and a base 11, the base 11 for fixing the fixed sample tube 2, the drive tube 4, the fixing block 8, and the fixing ring 9. The bottoms of both the drive tube 4 and the sample tube 2 are attached to a wooden support plate 12 by a fixing assembly, the wooden support plate 12 for sealing the bottom end of the housing 13, and a detonator is installed at the top end of the housing 13.

[0056] Example 5 Example 5 is a further improvement based on Example 4. The detonation component includes an explosive charge 6, a primer fixing plate 14, and a primer 15. The explosive charge 6 is laid on top of the main explosive charge 5, the bottom surface of the explosive charge layer is connected to the top of the fixing assembly, and the top surface of the explosive charge layer is in contact with the bottom surface of the primer fixing plate 14. The primer 15 is installed on the primer fixing plate 14. The explosive is the energy source of the synthesis device, and in the case of the device of this embodiment, the amount of explosive used is 260 kg. The main explosive is placed in the gap between the housing 13 and the drive pipe 4. In addition, RDX high-performance explosive is laid over the top surface to a thickness of 1 cm to 3 cm. The primer 15 is inserted into the primer positioning plate 14.

[0057] Polycrystalline diamond is synthesized using the apparatus of Example 5. The synthesis principle is as follows.

[0058] 1. It is possible to convert graphite into diamond and create specific high-temperature and high-pressure conditions that result in a high conversion rate.

[0059] This embodiment provides a column-face sliding (deformation) detonation double-tube impact synthesis apparatus. After the explosive is detonated at the top of the apparatus, a detonation wave is formed within the explosive, and the detonation wave propagates from top to bottom along the outer wall of the drive tube at a stable speed. Due to the action of high-pressure detonation products behind the detonation wavefront, the drive tube converges and slides toward the axis of the apparatus. During its flight in the cavity, at the interface between the explosive and the drive tube, the interaction of compression waves and rarefied waves causes the drive tube to continuously gain energy from the explosive and accelerate, thus causing the drive tube to converge toward the axis. Due to the convergence effect, its free surface velocity also increases. After the drive tube collides with the sample tube at high speed, a shock wave is generated within the sample tube, forming a stable detonation impact system, and the shock wave passes through the entire sample from top to bottom. As a result, the sample is uniformly compressed. Therefore, the conversion rate is very high and can reach more than 90%.

[0060] 2. Prevent graphitization. During impact compression, pressure is released. To minimize the reverse phase transition from diamond to graphite during the release process, impact quenching is achieved by adding a metal powder with excellent thermal conductivity (e.g., copper powder) to the sample. This requirement can be met by appropriately setting the mixing ratio of graphite to metal powder.

[0061] 3. High recovery rate The impact pressure between the drive tube and the sample tube far exceeds the Hugoniot elastic limit of the drive tube material, causing the material to enter the plastic region. Due to the accumulation effect and plastic deformation, the drive tube tightly coats the sample tube and the seals at both ends. As a result, the drive tube, sample tube, and seals at both ends form a highly strong composite tube through detonation, which is formed as a collection container for the generated diamonds. Furthermore, when the high-pressure detonation product expands at the end of the device to disperse into the air, a tensile force (impact momentum) is generated at the end opening. If this becomes sufficiently large, the opening of the sample tube may rupture, causing the sample inside the tube to be discharged and leaked. To avoid tensile stress on the end of the sample tube, fixing blocks and fixing rings are installed at both ends of the sample tube and the drive tube. This protects the ends of the collection container from explosion-induced damage. A diamond recovery rate of 100% can be achieved.

[0062] After synthesizing diamonds by detonation, the sample (i.e., a mixture of diamond, graphite, and copper powder) is taken out of a composite tube recovery container, selectively treated with acid oxidation to separate the diamonds from the sample, and then subsequent purification processes such as sieving and classification of the diamonds are performed.

[0063] As described above, the detonation apparatus according to this disclosure can create high-temperature and high-pressure conditions for the conversion of graphite to diamond, and can uniformly compress the sample graphite within the apparatus to convert it into high-purity polycrystalline diamond. The conversion rate of the present invention can be significantly increased and can reach 90% or more. Furthermore, the high-purity polycrystalline diamond obtained by the conversion can be completely recovered, and the recovery rate can reach 100%.

[0064] The inventors have used this apparatus to synthesize high-purity nanostructured polycrystalline diamond, achieving a conversion rate of over 90% and 100% recovery of the resulting high-purity nanostructured polycrystalline diamond. Its particle size ranges from 0 to 32 μm and follows a normal distribution, enabling mass production.

[0065] The specific embodiments described above further illustrate the purpose, technical proposal, and beneficial effects of this disclosure. However, the above description is merely a description of specific embodiments of this disclosure and does not limit the scope of protection of this disclosure. All modifications, equivalent substitutions, improvements, etc., that do not deviate from the essence and spirit of this disclosure are all within the scope of protection of this disclosure. [Explanation of symbols]

[0066] 1 sample 2 sample tubes 3 Cavities 4 Drive pipe 5. Main explosive 6. Detonator 7 End plug 8 Fixed Blocks 9. Fixing ring 10 Cover boards 11 Bass 12 Wooden support board 13 Housing 14 Detonator Positioning Plate 15 Detonator

Claims

1. The device comprises a drive pipe (4), a sample pipe (2), a fixing assembly, and end plugs (7) installed at both ends of the sample pipe (2). The drive tube (4) is mounted around the outside of the sample tube (2), a cavity (3) is formed between the drive tube (4), the sample tube (2), and the end plug (7), and the fixing assembly is installed at both ends of the drive tube (4) and the sample tube (2), and is for fixing the drive tube (4) and the sample tube (2). The fixing assembly installed on the top of the drive pipe (4) includes a fixing ring (9) and at least one cover plate (10), One end of the fixing ring (9) is connected to the top of the drive pipe (4), and the other end of the fixing ring (9) is connected to the cover plate (10). The cover plate (10) is for sealing the cavity (3), The fixing assembly installed at the bottom of the drive pipe (4) includes a fixing ring (9) and a base (11), One end of the fixing ring (9) is connected to the bottom of the drive pipe (4), and the other end of the fixing ring (9) is connected to the base (11). The base (11) serves the role of fixing and supporting, The top and / or bottom of the drive tube (4) and the end of the fixing ring (9) are connected by a joint to form a coaxial cylindrical structure. The aforementioned fixed assembly further includes a fixed block (8), The fixing block (8) is installed inside the fixing ring (9), one end of the fixing block (8) is connected to the end plug (7), and the other end of the fixing block (8) is connected to the cover plate (10) or the base (11). When the detonation wave propagates to the connection point between the end of the drive pipe (4) and the end plug (7) and the fixed assembly, the detonation wave causes the connection between the end of the drive pipe (4) and the end plug (7) to be released at the connection point, and the end of the drive pipe (4) and the end plug (7) to be connected with sufficient force to cause them to fly outwards. A double-tube connection structure for detonation synthesis, characterized by the following features.

2. The double-tube connection structure for detonation synthesis according to claim 1, characterized in that the circumferential gap between the inner wall of the drive tube (4) and the outer wall of the sample tube (2) is defined as the cavity (3).

3. The double-tube connection structure for detonation synthesis according to claim 1 or 2, characterized in that the outer diameter of the portion of the end plug (7) that is covered and in contact with by the drive tube (4) is smaller than the outer diameter of the sample tube (2).

4. The double-tube connection structure for detonation synthesis according to claim 3, characterized in that the end plug (7) has a tapered structure, and the large-diameter end of the tapered structure is connected to the sample tube (2).

5. The double-pipe connection structure for detonation synthesis according to claim 1, characterized in that a position limiting ring I extending outward along the axial direction is installed on the bottom end face and / or top end face of the drive pipe (4), a position limiting ring II extending outward along the axial direction is installed on the end face of the corresponding fixing ring (9), and the drive pipe (4) and the fixing ring (9) are connected by the ring arrangement of the position limiting ring I and the position limiting ring II.

6. The device comprises a housing (13) and a double-pipe connection structure for detonation synthesis according to any one of claims 1 to 5, which is installed inside the housing (13). The main explosive (5) is filled into the cavity between the inner wall of the housing (13) and the outer wall of the drive pipe (4). The bottom ends of both the drive tube (4) and the sample tube (2) are attached to the support plate (12) via a fixed assembly, and the support plate (12) is for sealing the bottom end of the housing (13). A detonation synthesis device characterized in that a detonation component is installed at the top of the housing (13).

7. The detonation component includes an explosive charge (6), a detonator fixing plate (14), and a detonator (15). The detonator (6) is laid on top of the main explosive (5), a detonator fixing plate (14) is placed on the detonator (6), and the detonator (15) is fixed to the detonator fixing plate (14). The detonation synthesis apparatus according to feature 6.

8. The use of a double-pipe connection structure for detonation synthesis according to any one of claims 1 to 5, or a detonation synthesis apparatus according to claim 6 or 7, The use of the double-pipe connection structure or detonation synthesis apparatus for detonation synthesis, characterized in that the double-pipe connection structure or detonation synthesis apparatus is used to cause a phase transition of a material to a high-pressure phase, or to pulverize a hard material.

9. A method for manufacturing a high-strength composite tube or a high-strength pressure vessel, A manufacturing method characterized by producing the high-strength composite pipe or the high-strength pressure vessel by detonation using the double-pipe connection structure for detonation synthesis described in any one of claims 1 to 5 or the detonation synthesis apparatus described in claim 6 or 7.

Images