Ultrahigh pressure generation assembly based on large-cavity press

Abstract

The invention relates to an ultrahigh pressure generation assembly based on a large-cavity press, which belongs to the technical field of fluid pressure and structurally comprises a regular octahedron (1) and a sample bin (2), a first pair of cylindrical plugs (3) and a second pair of circular truncated cone-shaped plugs (4) are sequentially and symmetrically distributed at two ends of the sample bin (2) from inside to outside, and the sample bin (2), the first pair of plugs (3) and the second pair of plugs (4) are coaxial; the first pair of plugs (3) and the second pair of plugs (4) are made of boron-doped diamond materials, the middle of the sample bin (2) is used for being filled with standard pressure substances or samples needing high-pressure experiments, and the height of the standard pressure substances or the samples is 0.7 mm. According to the invention, the conductive boron-doped diamond is adopted as the assembly body, so that the boosting efficiency can be improved, the sample pressure can be calibrated by testing an electric signal, the required external oil pressure is smaller under the same internal pressure, and the secondary anvil cell can be better protected.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid pressure, and in particular relates to an ultra-high pressure generating assembly based on a large cavity press. Background Art

[0002] As an extreme research method, high pressure technology can deeply explore the structural changes and electronic property regulation of materials under extreme conditions. This method is not only of great significance in basic scientific research, but also plays an increasingly important role in application fields such as materials science and geology. In nature, most substances exist in high-pressure environments. For example, the pressure inside the earth is about 350 GPa. This extreme condition has a profound impact on the physical and chemical properties of rocks. The pressure at the center of the sun is as high as 10 6 GPa, which allows nuclear fusion reactions in its core region to proceed. The central pressure of a neutron star is as high as 10 26 GPa, forming ultra-dense matter, which provides important clues for understanding cosmic physics. Therefore, the development of high-pressure technology is not only an important means of geological and geographical research, but also provides the possibility for the synthesis of metastable materials with new structures and excellent performance. These materials show broad application prospects in the fields of catalysis, energy storage and electronic devices. By exploring the behavior of matter under high pressure, scientists can design materials with specific functions and promote scientific and technological progress and innovation. In addition, high-pressure research may also reveal some unknown physical phenomena and further expand our understanding of the material world.

[0003] Large cavity presses are important equipment for high-pressure experiments, capable of preparing millimeter-scale or even centimeter-scale samples. This type of equipment plays an important role in the research of earth science, materials science and related fields. At present, the upper pressure limit of ordinary commercial large cavity presses is usually between 25-27 GPa, and expanding this pressure limit is crucial for a deep understanding of the material properties of the earth's interior and the synthesis of new materials. In order to improve the boosting efficiency, researchers usually use hard tungsten carbide as the secondary anvil. This material can effectively improve the speed and efficiency of boosting due to its excellent hardness and wear resistance. However, the use of hard materials also brings some problems, such as the limited number of uses of the secondary anvils and the easy occurrence of hammer-breaking under high-pressure conditions. These problems not only affect the stability of the experiment, but also limit the long-term use of the equipment. Therefore, it is particularly necessary to find an effective assembly scheme to improve the boosting efficiency.

[0004] Chinese patent ZL2024102183848 (the previous research result of this research group) discloses a method for improving the boosting efficiency of a large-cavity compressor based on the principle of large-mass support. The boosting efficiency is improved by using diamond / tungsten carbide plugs, and higher cavity pressure is achieved under lower oil pressure. However, the technical solution of this patent still has certain shortcomings: the side pressure is low, the sample is easy to overflow, and the pressure is easy to drop, so the boosting efficiency still has room for improvement. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the background technology and provide an ultra-high pressure generating assembly based on a large cavity press to improve the pressure boosting efficiency of the large cavity press.

[0006] The technical solution adopted by the present invention is as follows:

[0007] An ultra-high pressure generating assembly based on a large cavity press, the structure includes a regular octahedron 1 and a sample chamber 2, the sample chamber 2 is located at the center of the regular octahedron 1, characterized in that the side length of the regular octahedron 1 is 7mm, the distance between the two opposite sides is 5.7mm, the sample chamber 2 is cylindrical in shape, with a height of 1.2mm, an inner diameter of 1.0mm, and an outer diameter of 1.5mm, and a first pair of cylindrical plugs 3 and a second pair of truncated cone-shaped plugs 4 are symmetrically distributed from the inside to the outside at both ends of the sample chamber 2, wherein the bottom surface diameter of the first pair of plugs 3 is 1.0mm, and each height is 1.5mm, the inner bottom surface diameter of the second pair of plugs 4 is 1.0mm, the outer bottom surface diameter is 1.4mm, and the height is 1.0mm; the sample chamber 2, the first pair of plugs 3, and the second pair of plugs 4 are coaxial; the first pair of plugs 3 and the second pair of plugs 4 are both boron-doped diamond materials, and the concentration of boron doping is 4692 ppm, the middle of the sample chamber 2 is used to fill the standard pressure material or the sample requiring high pressure experiment, and the height of the standard pressure material or the sample is 0.7 mm.

[0008] Preferably, the material of the sample chamber 2 is hard magnesium oxide, aluminum oxide, or zirconium oxide, and the material of the regular octahedron 1 is magnesium oxide doped with chromium oxide.

[0009] Preferably, the ultra-high pressure generating assembly based on a large cavity press is used for a Walker / Kawai or D-DIA type large cavity press.

[0010] Beneficial effects:

[0011] 1. When the external oil pressure of the large cavity press is the same, the present invention uses conductive boron-doped diamond as an assembly, which can not only improve the boosting efficiency, but also boron-doped diamond has conductive properties and can calibrate the sample pressure by testing electrical signals, which is more convenient to use.

[0012] 2. Under the same internal pressure, the assembly using the super-hard BDD requires less external oil pressure, which results in less pressure on the secondary anvil, which helps to better protect the secondary anvil. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the ultra-high pressure generating assembly based on a large cavity press of the present invention.

[0014] Figure 2 This is a schematic diagram of the conventional pressurized standard pressure experiment assembly of Example 2.

[0015] Figure 3 is a schematic diagram of the octahedron of a Walker-type press.

[0016] Figure 4 This is a curve showing changes in oil pressure and resistance value in the ultra-high pressure generation experiment of Example 2.

[0017] Figure 5 It is the change curve of oil pressure and resistance value in the conventional pressurization and standard pressure experiment of Example 3.

[0018] Figure 6 It is a comparison of the standard pressure curves of the ultra-high pressure generating assembly based on the large cavity press of Example 2 (the present invention) and the large mass supporting assembly of Example 3 (the prior art). DETAILED DESCRIPTION

[0019] Example 1 Specific structure and preparation method of the present invention

[0020] A through hole with a diameter of 1.5 mm is punched through a pair of parallel faces in the center of an octahedron (7 mm in side length, 5.7 mm in distance between two opposite faces, made of magnesium oxide doped with chromium oxide) of a conventional Walker or Kawai press. A cylindrical sample chamber made of hard magnesium oxide with a height of 1.2 mm, an inner diameter of 1.0 mm, and an outer diameter of 1.5 mm is embedded in the center of the through hole. The remaining part of the through hole is blocked with ordinary magnesium oxide material and integrated with the octahedron before a new through hole is punched. Figure 1As shown, the two sections of the through hole near the bottom of the octahedron are truncated cone-shaped, and the rest is cylindrical with a diameter of 1.0 mm. The upper and lower bottom diameters of the truncated cone are 1.0 mm and 1.4 mm, respectively, and the height is 1.0 mm. The standard pressure material (or the sample that needs to be treated with high pressure) is filled in the middle of the sample chamber, and the filling height is 0.7 mm. The first pair of plugs and the second pair of plugs are placed at both ends of the standard pressure material 5 in sequence. The diameter of the first pair of plugs is 1.0 mm, and the height is 1.5 mm. The second pair of plugs are truncated cones with upper and lower bottom diameters of 1.0 mm and 1.4 mm, respectively, and a height of 1.0 mm. The first pair of plugs and the second pair of plugs are boron-doped diamond materials (B element doping concentration is about 4692 ppm), and the total height of the standard pressure material and the two pairs of plugs is 5.7 mm (i.e., the thickness of the octahedron).

[0021] Example 2 Ultra-high pressure generation experiment

[0022] Put the weighed standard pressure block (GaAs material) into an agate grinding body, add a small amount of alcohol, and grind slowly for 2 to 3 hours. After the alcohol evaporates, put the powder sample into a glass bottle and anneal it at 100°C for 2 hours at a heating rate of 5°C per minute in a vacuum atmosphere in a vacuum muffle furnace. Then cool it automatically to room temperature. The obtained sample is used as the standard pressure material.

[0023] According to the assembly sequence of Example 1, the pressure-standard substance 5 is placed in the large-cavity ultra-high pressure generating assembly of the present invention, the second pair of plugs 4 are connected to the multimeter with a wire, and the resistance value of the pressure-standard substance 5 is monitored by the multimeter with pressure changes. The assembled octahedron is placed in the Walker type press. The pressure increase rate is 3min / bar, and the resistance value change of the sample is recorded. The change curve of oil pressure and resistance is as follows: Figure 4 As shown, according to the resistance value following the pressure mutation point, the oil pressure value at this time is calibrated as the GaAs phase change pressure value. Since the GaAs phase change pressure is 18.9 GPa, when the cavity pressure is 18.9 GPa, the oil pressure needs to be 62 Bar.

[0024] Example 3 Conventional pressurized standard pressure experiment

[0025] Place the weighed GaAs block in an agate grinding body, add a small amount of alcohol, and grind slowly for 2 to 3 hours. After the alcohol evaporates, put the powder sample into a glass bottle and anneal it at 100°C for 2 hours at a heating rate of 5°C per minute in a vacuum atmosphere in a vacuum muffle furnace. Then cool it automatically to room temperature. The obtained sample is used as a standard pressure substance.

[0026] Figure 2 The schematic diagram of the conventional pressurization test assembly is shown in Figure 1. The octahedron (side length 8 mm, distance between two opposite faces 6.3 mm) of the Walker press is Figure 3 A through hole with a diameter of 1mm is made in the center of the sample chamber as shown in the figure. The standard pressure substance is filled to the center of the sample chamber with a filling height of 0.8mm. A molybdenum column (or copper column) with a diameter of 1mm and a height of 3.6mm is placed at the upper and lower ends of the standard pressure substance as a plug. The two plugs are connected to a multimeter with a wire. The resistance value of the standard pressure substance is monitored with a multimeter as a function of pressure. The assembled octahedron is placed in a Walker-type press. The pressure increase rate is 3min / bar, and the change in the resistance value of the sample is recorded, as shown in the figure. Figure 5 As shown, according to the resistance value following the pressure mutation point, the oil pressure value at this time is calibrated as the GaAs phase change pressure value, and the GaAs phase change pressure is 18.9 GPa. Therefore, when the cavity pressure is 18.9 GPa, the required oil pressure is 475 Bar.

[0027] The standard pressure curves of the ultra-high pressure generating assembly based on the large cavity press and the conventional large mass supporting assembly measured in the above Examples 2 and 3 are as follows: Figure 6 As shown by Figures 4 to 6 It can be seen that the pressure-increasing efficiency of the ultra-high pressure generating device based on the large-cavity press provided by the present invention is significantly higher than that of the currently disclosed prior art. This is mainly due to the fact that the present invention optimizes the design of the sample cavity and the plug part.

Claims

1. An ultra-high pressure generating assembly based on a large cavity press, the structure comprising a regular octahedron (1) and a sample chamber (2), wherein the sample chamber (2) is located at the center of the regular octahedron (1), characterized in that: The side length of the regular octahedron (1) is 7 mm, and the distance between two opposite faces is 5.7 mm. The sample chamber (2) is cylindrical in shape, with a height of 1.2 mm, an inner diameter of 1.0 mm, and an outer diameter of 1.5 mm. A first pair of cylindrical plugs (3) and a second pair of truncated cone plugs (4) are symmetrically distributed from the inside to the outside at both ends of the sample chamber (2), wherein the bottom diameter of the first pair of plugs (3) is 1.0 mm, and each is 1.5 mm high. The inner bottom diameter of the second pair of plugs (4) is 1.0 mm, the outer bottom diameter is 1.4 mm, and the height is 1.0 mm. The sample chamber (2), the first pair of plugs (3), and the second pair of plugs (4) are coaxial. The first pair of plugs (3) and the second pair of plugs (4) are both made of boron-doped diamond material, and the boron doping concentration is 4692 ppm. The middle of the sample chamber (2) is used to fill a standard pressure substance or a sample requiring a high pressure experiment, and the height of the standard pressure substance or sample is 0.7 mm.

2. The ultra-high pressure generating assembly based on a large cavity press according to claim 1, characterized in that: The material of the sample chamber (2) is hard magnesium oxide, aluminum oxide, and zirconium oxide, and the material of the regular octahedron (1) is magnesium oxide doped with chromium oxide.

3. The ultra-high pressure generating assembly based on a large cavity press according to claim 1, characterized in that: The ultra-high pressure generating device based on a large cavity press is used for a Walker / Kawai or D-DIA type large cavity press.

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