A diamond high-pressure inclusion and preparation method thereof

Abstract

The present application provides a diamond high-pressure inclusion and a preparation method thereof. The diamond high-pressure inclusion comprises a composite material and diamond encapsulating the composite material. The composite material comprises a pressure-bearing material and a low-pressure phase pressurizing agent, wherein the pressurizing agent is selected from at least one of SiO2 and GeO2. The diamond high-pressure inclusion provided by the present application has a high internal pressure and can maintain the internal high pressure for a long time, which is conducive to in-situ measurement of the pressure-bearing material under high pressure and does not limit the size of the pressure-bearing material. At the same time, the diamond high-pressure inclusion of the present application can be applied to pressure-bearing materials with stable physicochemical properties as well as pressure-bearing materials with more active physicochemical properties, thereby expanding the application range of the diamond high-pressure inclusion.

Description

Technical Field

[0001] The present application relates to the technical field of high-pressure materials, and in particular to a diamond high-pressure inclusion and a preparation method thereof. Background Art

[0002] High-pressure techniques play a crucial role in materials science and condensed matter physics because they enable the exploration of novel physical and chemical phenomena in materials under extreme conditions. Traditional high-pressure experiments typically use external pressure-generating devices such as diamond anvil cells (DACs) or large-cavity presses. While these methods are crucial for advancing our understanding of materials under high pressure, they also have inherent limitations, including difficulty maintaining high pressure for extended periods, limited sample size, and restricted in-situ measurements. In recent years, encapsulating materials within nanocrystalline diamond capsules (NDCs) has emerged as a groundbreaking alternative to traditional high-pressure techniques. This innovative approach involves the synthesis of diamond capsules or diamond inclusion films that can capture and maintain high-pressure phases. The main advantage of this method is its ability to preserve the unique high-pressure-induced properties of the material without relying on continuous external pressure, thereby allowing for detailed characterization of the material and facilitating its potential applications.

[0003] However, due to factors such as the compressibility of solid materials and the stress release of diamond and solid materials during annealing, the packaging pressure of diamond capsules or diamond inclusion films is typically less than 4 GPa. This pressure range significantly limits the application range of pressure packaging capsules or films. In addition, due to the high activity of carbon sources under high temperature and pressure, they easily react chemically with solid materials. Therefore, traditional pressure packaging is limited to inert gases and a very small number of inert metals. It is not suitable for applications under high pressure for more active metals and oxides with rich physical and chemical properties. Summary of the Invention

[0004] The purpose of this application is to provide a diamond high-pressure inclusion and its preparation method, which can increase the internal pressure of the diamond high-pressure inclusion encapsulating a pressurized material and maintain the internal high pressure for a long time. This inclusion is also applicable to pressurized materials with relatively active physical and chemical properties, thereby expanding the application range of the diamond high-pressure inclusion. The specific technical solution is as follows:

[0005] The first aspect of the present application provides a diamond high-pressure inclusion, which includes a composite material and diamonds that include the composite material. The composite material includes a pressurized material and a low-pressure phase pressurizing agent, the pressurizing agent is selected from at least one of SiO2 and GeO2, and the pressurized material is selected from at least one of a metal element, a metal oxide, a non-metal element, and a ceramic material.

[0006] In one embodiment, the pressurizing agent and the pressurized material are mixed with each other, or the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure.

[0007] In one embodiment, the metal element is selected from at least one of platinum, gold, rhenium, and iron, the metal oxide is selected from at least one of aluminum oxide, zirconium oxide, and magnesium oxide, the non-metal element is selected from at least one of P and Si, and the ceramic material is selected from at least one of tungsten carbide (WC) and zirconium carbide (ZrC).

[0008] In one embodiment, the internal pressure of the diamond high-pressure inclusion is 10 GPa-22 GPa.

[0009] The second aspect of the present application provides a method for preparing a diamond high-pressure inclusion according to the first aspect of the present application, comprising the following steps:

[0010] 1) preparing a precursor, comprising: mixing the pressurizing agent in a normal pressure phase with an object to be wrapped to obtain the precursor; or coating the pressurizing agent in a normal pressure phase on the surface of the object to be wrapped to form a core-shell structure to obtain the precursor; the object to be wrapped comprises the pressure-bearing material or a raw material for synthesizing the pressure-bearing material;

[0011] 2) mixing the precursor and the carbon source at a mass ratio of 1:(5-25), and then subjecting the mixture to a high-temperature and high-pressure treatment to convert the carbon source into diamond and convert the pressurizing agent from a normal-pressure phase to a high-pressure phase, thereby obtaining a diamond high-pressure capsule; the high-temperature and high-pressure treatment is performed at a temperature of 1400° C. to 2100° C. and a pressure of 12 GPa to 30 GPa;

[0012] 3) High-temperature annealing is performed on the diamond high-pressure capsule at a pressure of 0.5 GPa-6 GPa and a temperature of 800° C.-2400° C. to transform the pressurizing agent from a high-pressure phase to a low-pressure phase, thereby obtaining the diamond high-pressure inclusion.

[0013] In one embodiment, the mass ratio of the pressurizing agent to the object to be wrapped in step 1) is 1:(0.1-0.5).

[0014] In one embodiment, the method of coating the pressurizing agent in normal pressure phase on the surface of the object to be coated to form a core-shell structure is selected from chemical gelation or magnetron sputtering.

[0015] In one embodiment, the carbon source is selected from at least one of graphite, amorphous diamond powder, onion carbon, carbon nanotubes, amorphous carbon powder, and nano-diamond powder.

[0016] The present application provides a diamond high-pressure inclusion and a preparation method thereof, wherein the diamond high-pressure inclusion comprises a composite material and diamonds encapsulating the composite material, wherein the composite material comprises a pressure-bearing material and a low-pressure phase pressurizing agent, wherein the pressurizing agent is selected from at least one of SiO2 and GeO2, and the pressure-bearing material is selected from at least one of a metal element, a metal oxide, a non-metal element, and a ceramic material. The diamond high-pressure inclusion provided by the present application has a high internal pressure and can maintain the internal high pressure for a long time, which is conducive to in-situ measurement of the pressure-bearing material under high pressure and does not limit the size of the pressure-bearing material. At the same time, the diamond high-pressure inclusion of the present application can be applied to pressure-bearing materials with stable physicochemical properties, and can also be applied to pressure-bearing materials with more active physicochemical properties, thereby expanding the application range of the diamond high-pressure inclusion.

[0017] Of course, it is not necessary to achieve all the advantages described above at the same time when implementing any product or method of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other embodiments can also be obtained based on these drawings.

[0019] Figure 1 The X-ray diffraction (XRD) analysis patterns of the diamond high-pressure capsule and diamond high-pressure inclusion prepared in Example 7, wherein Figure a is the XRD analysis pattern of the diamond high-pressure capsule, and Figure b is the XRD analysis pattern of the diamond high-pressure inclusion;

[0020] Figure 2A This is a transmission electron microscope (TEM) photograph of Fe under high pressure in the diamond high-pressure inclusion of Example 13;

[0021] Figure 2B This is a high-resolution transmission electron microscopy (HR-TEM) image of Fe under high pressure in the diamond high-pressure inclusion of Example 13;

[0022] Figure 2C This is an electron diffraction photograph of Fe under high pressure in the diamond high-pressure inclusion of Example 13;

[0023] Figure 3 These are the energy loss spectrum test results of Fe under high pressure in the diamond high-pressure inclusions of Example 13. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present application and the accompanying drawings to clearly and completely describe the technical solutions in this application. Obviously, the embodiments described are only part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0025] Traditional diamond capsules or diamond inclusion films are prepared by mixing a carbon source with the object to be included and then sintering under high pressure to generate diamond under high temperature and high pressure. The difference in compressibility between diamond and the object to be included is utilized to leave some residual stress at room temperature and pressure. However, due to factors such as the compressibility of the solid material to be included is not as different from that of diamond as that of gas and diamond, and the stress release of diamond and solid materials during the annealing process, the internal pressure of the diamond capsule or diamond inclusion film is usually lower than 4GPa, which is not enough to meet the application range of most materials. In the diamond high-pressure inclusion of the present application, diamond is a rigid material, and a certain space is reserved for the pressurized material. The special high-pressure phase change behavior of the pressurizing agent of the present application is utilized to induce the reversible phase change of the pressurizing agent under high pressure to cause volume expansion, thereby achieving continuous extrusion of the pressurized material, thereby pressurizing the interior of the diamond high-pressure inclusion.

[0026] The first aspect of the present application provides a diamond high-pressure inclusion, which includes a composite material and diamonds that include the composite material. The composite material includes a pressurized material and a low-pressure phase pressurizing agent, the pressurizing agent is selected from at least one of SiO2 and GeO2, and the pressurized material is selected from at least one of a metal element, a metal oxide, a non-metal element, and a ceramic material.

[0027] In the diamond high-pressure inclusion provided by the present application, the diamond serves as a rigid shell and is not easily deformed by external forces. The volume of the pressurizing agent in the low-pressure phase will expand. The rigid diamond shell can limit the volume expansion of the pressurizing agent, thereby increasing the internal pressure of the diamond high-pressure inclusion and being able to maintain the internal high pressure for a long time, which is conducive to in-situ measurement of pressurized materials under high pressure and does not limit the size of the pressurized materials. Moreover, the diamond high-pressure inclusion of the present application can be applied to pressurized materials with stable physicochemical properties, as well as to pressurized materials with relatively active physicochemical properties, thereby expanding the application range of the diamond high-pressure inclusion.

[0028] In one embodiment, the pressurizing agent and the pressurized material are mixed with each other, or the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure. In the present application, for pressurized materials with stable physicochemical properties, a composite material in which the pressurizing agent and the pressurized material are mixed with each other can be used, or a composite material in which the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure can be used. For pressurized materials with relatively active physicochemical properties, a composite material in which the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure can be used, and the relatively active pressurized material can be encapsulated in the pressurizing agent, thereby expanding the application range of diamond high-pressure inclusions.

[0029] In one embodiment, the metal element is selected from at least one of platinum, gold, rhenium, and iron, the metal oxide is selected from at least one of aluminum oxide, zirconium oxide, and magnesium oxide, the non-metallic element is selected from at least one of P and Si, and the ceramic material is selected from at least one of WC and ZrC.

[0030] In one embodiment, the internal pressure of the diamond high-pressure inclusion is 10 GPa-22 GPa. For example, the internal pressure of the diamond high-pressure inclusion can be 10 GPa, 11 GPa, 12 GPa, 13 GPa, 14 GPa, 15 GPa, 16 GPa, 17 GPa, 18 GPa, 19 GPa, 20 GPa, 21 GPa, 22 GPa, or a range consisting of any two of these values. The present application can achieve an internal pressure of 10 GPa-22 GPa within the diamond high-pressure inclusion and maintain this high-pressure state for a long time, which is beneficial for in-situ measurement of pressurized materials under high pressure, thereby facilitating the characterization of properties of pressurized materials and their potential applications.

[0031] The second aspect of the present application provides a method for preparing a diamond high-pressure inclusion according to the first aspect of the present application, comprising the following steps:

[0032] 1) preparing a precursor, comprising: mixing the pressurizing agent in a normal pressure phase with an object to be wrapped to obtain the precursor; or coating the pressurizing agent in a normal pressure phase on the surface of the object to be wrapped to form a core-shell structure to obtain the precursor; the object to be wrapped comprises the pressure-bearing material or a raw material for synthesizing the pressure-bearing material;

[0033] 2) mixing the precursor and the carbon source at a mass ratio of 1:(5-25), and then subjecting the mixture to a high-temperature and high-pressure treatment to convert the carbon source into diamond and convert the pressurizing agent from a normal-pressure phase to a high-pressure phase, thereby obtaining a diamond high-pressure capsule; the high-temperature and high-pressure treatment is performed at a temperature of 1400° C. to 2100° C. and a pressure of 12 GPa to 30 GPa;

[0034] 3) High-temperature annealing is performed on the diamond high-pressure capsule at a pressure of 0.5 GPa-6 GPa and a temperature of 800° C.-2400° C. to transform the pressurizing agent from a high-pressure phase to a low-pressure phase, thereby obtaining the diamond high-pressure inclusion.

[0035] For example, the mass ratio of the precursor to the carbon source can be 1:5, 1:7, 1:10, 1:12, 1:15, 1:18, 1:20, 1:22, 1:25, or a range consisting of any two values ​​therein. The temperature of the high temperature and high pressure treatment can be 1400°C, 1500°C, 1600°C, 1700°C, 1800°C, 1900°C, 2000°C, 2100°C, or a range consisting of any two values ​​therein, and the pressure can be 12 GPa, 13 GPa, 15 GPa, 16 GPa, 18 GPa, 20 GPa, 22 GPa, 23 GPa, 25 GPa, 26 GPa, 28 GPa, 30 GPa, or a range consisting of any two values ​​therein. The temperature of the high-temperature annealing can be 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C, 1800°C, 1900°C, 2000°C, 2100°C, 2200°C, 2300°C, 2400°C, or a range consisting of any two values ​​therein, and the pressure can be 0.5GPa, 1GPa, 2GPa, 3GPa, 4GPa, 5GPa, 6GPa, or a range consisting of any two values ​​therein. The present application does not specifically limit the duration of the high-temperature and high-pressure treatment, as long as the purpose of the present application can be achieved; for example, the duration of the high-temperature and high-pressure treatment can be 10s-30min. The present application does not specifically limit the duration of the high-temperature annealing, as long as the purpose of the present application can be achieved; for example, the duration of the high-temperature and high-pressure treatment can be 10s-10h. The normal pressure phase of the pressurizing agent described in this application refers to the crystal phase of the pressurizing agent at normal pressure, i.e., 1 atmosphere. Taking silicon oxide SiO2 as an example, its high-pressure phase refers to tetragonal quartz, i.e., stibnite, and its low-pressure phase refers to trigonal quartz, i.e., α-quartz.

[0036] In the present application, after high temperature and high pressure treatment, the carbon source is converted into diamond, and the pressurizing agent is transformed from the normal pressure phase to the high pressure phase. Then, the diamond high pressure capsule is subjected to high temperature annealing under a relatively low pressure. In this process, the diamond, as a rigid shell, is not easily deformed by external forces, and the pressurizing agent undergoes a reversible phase change from the high pressure phase to the low pressure phase. The volume of the pressurizing agent in the low pressure phase will expand, and at the same time, the rigid diamond shell will limit the volume expansion of the pressurizing agent, so that the pressurizing agent continues to squeeze the pressurized material inside the diamond high pressure inclusion, thereby significantly increasing the internal pressure of the diamond high pressure inclusion. The preparation method of the diamond high pressure inclusion provided in the present application utilizes the volume expansion caused by the reversible phase change of the pressurizing agent under high pressure, significantly increases the internal pressure of the diamond high pressure inclusion, and can maintain the internal high pressure for a long time. In addition, the carbon source is highly active under high temperature and high pressure and is easy to react chemically with the object to be encapsulated. The present application can form a shell-core structure by coating the pressurizing agent on the surface of the object to be encapsulated, so that the object to be encapsulated is separated from the carbon source, thereby significantly improving the success rate of preparing diamond high-pressure inclusions and expanding the application range of diamond high-pressure inclusions. It is also applicable to pressurized materials with more active physical and chemical properties.

[0037] In the present application, the object to be packaged includes the synthetic raw material of the pressure-bearing material, which can be synthesized by the high temperature and high pressure treatment. The present application does not particularly limit the synthetic raw material of the pressure-bearing material, as long as it can synthesize the pressure-bearing material that can be packaged under high pressure.

[0038] In one embodiment, the mass ratio of the pressurizing agent to the object to be wrapped in step 1) is 1:(0.1-0.5). For example, the mass ratio of the pressurizing agent to the object to be wrapped can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, or a range consisting of any two of these values.

[0039] In the present application, the method for coating the normal-pressure phase pressurizing agent on the surface of the object to be coated to form a core-shell structure is not particularly limited, as long as the purpose of the present application can be achieved. In one embodiment, the method for coating the normal-pressure phase pressurizing agent on the surface of the object to be coated to form a core-shell structure is selected from a chemical gel method or a magnetron sputtering method.

[0040] The present application does not particularly limit the type of carbon source, as long as it can achieve the purpose of the present application; in one embodiment, the carbon source is selected from at least one of graphite, amorphous diamond powder, onion carbon, carbon nanotubes, amorphous carbon powder, and nano diamond powder.

[0041] In this application, the term "about" is defined as close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the term is defined as within 10%, preferably within 5%, more preferably within 1%, and even more preferably within 0.5%.

[0042] Hereinafter, the embodiments of the present application will be described in more detail with reference to Examples and Comparative Examples. Various tests and evaluations were performed according to the following methods. In addition, unless otherwise specified, "parts" and "%" are by mass.

[0043] Test methods and equipment:

[0044] Internal pressure of diamond high-pressure capsule, internal pressure of diamond high-pressure inclusion and high-pressure maintenance time test:

[0045] In situ X-ray diffraction measurements were performed on the diamond high-pressure capsule to obtain XRD diffraction patterns of the pressurized material. The XRD data were refined using Gsass software to calculate the unit cell parameters. The phase composition was determined by comparing the XRD data with the PDF-4 database cards from the International Center for Diffraction Data (ICDD). The ambient pressure of the pressurized material, which is the internal pressure of the diamond high-pressure capsule, was then calculated based on the known relationship between pressure and unit cell parameters, i.e., the equation of state of the pressurized material. X-ray diffraction measurements were performed using a D8 Venture X-ray diffractometer manufactured by Bruker, Germany. A molybdenum target light source with a wavelength of 0.6199 Å and an exposure time of 600 s was used.

[0046] The internal pressure of diamond high-pressure inclusions is obtained by the same method.

[0047] After 30 days (720 h), the internal pressure of the diamond high-pressure inclusion was measured again using the same method.

[0048] Dimensional testing of pressurized materials in diamond high-pressure inclusions:

[0049] The diamond high-pressure inclusions were placed under a scanning transmission electron microscope (STEM, JEM-ARM200F transmission electron microscope (JEOL, Japan)), and STEM tests were performed on the pressurized materials under high pressure in the diamond high-pressure inclusions to obtain the average diameter of the pressurized materials.

[0050] Example 1

[0051] 1) Mixing the atmospheric pressure phase pressurizing agent SiO2 and the object to be coated Pt in a mass ratio of 1:0.2 to obtain a precursor;

[0052] 2) The precursor obtained in step 1) is mixed with carbon source graphite at a mass ratio of 1:20, and then subjected to high temperature and high pressure treatment to convert the carbon source into diamond and transform the pressurizing agent in the precursor from a normal pressure phase to a high pressure phase, thereby obtaining a diamond high pressure capsule; the high temperature and high pressure treatment temperature is 1500°C, the pressure is 18 GPa, and the time is 1 minute;

[0053] 3) The diamond high-pressure capsule obtained in step 2) is subjected to high-temperature annealing at a pressure of 4 GPa and a temperature of 1400°C for 10 minutes to transform the pressurizing agent from a high-pressure phase to a low-pressure phase, thereby obtaining a diamond high-pressure inclusion, which includes a composite material composed of a mixture of the pressurizing agent SiO2 and the pressure-bearing material Pt, and diamond encapsulating the composite material.

[0054] Example 2 to Example 12

[0055] Except for adjusting the corresponding preparation parameters according to Table 1, the rest is the same as Example 1.

[0056] Example 13

[0057] 1) Chemical gelation method:

[0058] Transfer 0.1g of nano-iron powder to a container and add 20mL of 90wt% ethanol to dilute it. Slowly add ammonia water while stirring to adjust the pH of the solution to 7-8. Add tetraethyl orthosilicate (TEOS) dropwise. TEOS undergoes hydrolysis and condensation reaction under the catalysis of ammonia water to form a silica coating on the surface of the iron nanoparticles. During this process, stirring is continued for about half an hour to ensure that the reaction is fully carried out to obtain a normal pressure phase supercharger coated on the surface of the pressurized material to form a shell-core structure precursor, wherein the mass ratio of the supercharger to the material to be coated is approximately 1:0.2;

[0059] 2) The precursor obtained in step 1) is mixed with carbon source graphite at a mass ratio of 1:20, and then subjected to high temperature and high pressure treatment to convert the carbon source into diamond and transform the pressurizing agent in the precursor from a normal pressure phase to a high pressure phase, thereby obtaining a diamond high pressure capsule; the high temperature and high pressure treatment temperature is 1500°C, the pressure is 18 GPa, and the time is 1 minute;

[0060] 3) annealing the diamond high-pressure capsule obtained in step 2) at a pressure of 4 GPa and a temperature of 1400° C. for 10 minutes to transform the pressurizing agent from a high-pressure phase to a low-pressure phase, thereby obtaining a diamond high-pressure inclusion, comprising a composite material in which the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure, and diamond encapsulating the composite material.

[0061] Comparative Example 1

[0062] Except that no pressurizing agent is added, the rest is the same as Example 1. The specific steps are as follows:

[0063] 1) Pt to be encapsulated and graphite as a carbon source are mixed at a mass ratio of 1:20, and then subjected to high temperature and high pressure treatment to convert the carbon source into diamond, thereby obtaining a diamond high-pressure capsule; the high temperature and high pressure treatment temperature is 1500°C, the pressure is 18GPa, and the time is 1 minute;

[0064] 2) High-temperature annealing is performed on the diamond high-pressure capsule obtained in step 1) at a pressure of 4 GPa and a temperature of 1400° C. for 10 minutes to obtain a diamond high-pressure inclusion comprising Pt and diamond encapsulating Pt.

[0065] Comparative Example 2 to Comparative Example 3

[0066] Except for adjusting the corresponding preparation parameters according to Table 1, the rest is the same as Example 1.

[0067] The preparation parameters of each embodiment or comparative example are shown in Table 1, and the performance parameter results are shown in Table 2.

[0068] Table 1

[0069]

[0070] Note: “ / ” in Table 1 indicates no corresponding preparation parameters.

[0071] Table 2

[0072]

[0073] Figure 1 The XRD analysis patterns of the diamond high-pressure capsule and the pressure-bearing material in the diamond high-pressure inclusion prepared in Example 7, wherein Figure a is the XRD analysis pattern of the pressure-bearing material in the diamond high-pressure capsule before annealing, and Figure b is the XRD analysis pattern of the pressure-bearing material in the diamond high-pressure inclusion. The black dots indicated by 01 in the figure are experimental values ​​(the denser the stack, the more likely it is to be a line shape), which refer to the XRD test results of the pressure-bearing material. Line 02 is a simulation, which refers to the curve obtained by simulating the XRD test results using Gsass software. Line 03 is the difference, which refers to the difference result of the comparison between the two. The small figure in the upper left corner of Figure b is a partial enlarged view of the XRD spectrum corresponding to the 2θ (Deg.°) value in Figure b. There are three split peaks, corresponding to 1, 2, and 3 marked in the spectrum in the middle of Figure b (obtained by XRD detection), which reflect the two unit cell volumes of Pt in the diamond high-pressure inclusion. According to Figure 1 The XRD analysis spectrum of the diamond high-pressure capsule in Figure a shows that the phase composition of the unannealed diamond high-pressure capsule is: quartz (P42 / mnm space group), unit cell parameters: a=4.179(4)Å, c=2.673(4)Å, unit cell volume V=46.697(3)ų. Diamond ( Space group), unit cell parameters: a=3.569(7)Å, V=45.487(8)ų. Platinum ( space group), unit cell parameters: a=3.926(0)Å, V=60.513(3)ų. According to Figure 1 The XRD analysis of the diamond high-pressure inclusion in Figure b shows that the phase evolution of the diamond high-pressure inclusion after annealing is as follows: coesite (C2 / c space group), unit cell parameters: a=6.503(2)Å, b=10.191(6)Å, c=6.913(7)Å, β=120.814(0)°, unit cell volume V=393.540(6)ų. Coesite, unit cell parameters: a=4.173(8)Å, c=2.671(5)Å, V=46.539(2)ų. Diamond, unit cell parameters: a=3.561(9)Å, V=45.190(3)ų. Platinum binary phase: Phase I: a=3.904(6)Å, V=59.529(1)ų; Phase II: a=3.860(0)Å, V=57.512(5)ų. By using the unit cell parameters, unit cell volume V and the state equation of Pt:

[0074] ,

[0075] (where B0 = 276.07 GPa, B'0 = 3, and V0 = 60.39 ų). The calculated ambient pressure of the Pt in the diamond high-pressure capsule before annealing is approximately 4 GPa. The unit cell parameters of the Pt in the diamond high-pressure inclusion after annealing correspond to 4 GPa and 15 GPa, respectively. This indicates that the ambient pressure of the pressurized Pt material in the diamond high-pressure inclusion in Example 7 is 15 GPa. The internal pressures of the diamond high-pressure capsules and diamond high-pressure inclusions in each Example or Comparative Example can be obtained using the same method. The results are shown in Table 2. A pressurizing agent, such as SiO2, forms a stishovite phase under the high pressures of this application. After annealing, the diamond high-pressure capsule forms a mixture of coesite, diamond, and other phases.

[0076] In the present application, the pressurized material in the diamond high-pressure inclusion can be measured in situ. Taking Example 13 as an example, the diamond high-pressure inclusion is placed under a scanning transmission electron microscope (STEM), and the Fe under high pressure in the diamond high-pressure inclusion is subjected to STEM testing and electron energy loss spectroscopy (EELS) analysis. A JEM-ARM200F transmission electron microscope (JEOL, Japan) equipped with a spherical aberration corrector (CEOS) is used to perform low-angle annular dark field (LAADF) and high-angle annular dark field (HAADF) image tests. The operating voltage is 200 kV, the spot size is 8°, and the convergence angle is selected as 30 mrad. The TEM photos, HR-TEM photos, and electron diffraction photos of Fe under high pressure are obtained, respectively, as shown in FIG. Figure 2A 、 Figure 2B 、 Figure 2C As shown, the energy loss spectrum test results of high-pressure phase Fe are obtained as follows Figure 3 The above results show that the diamond high-pressure inclusions of the present application can realize in-situ measurement of pressurized materials under high pressure, and thus obtain the physical and chemical properties of the pressurized materials under high pressure.

[0077] According to the results of Examples 1-13 and Comparative Examples 1-3 in Table 2, the internal pressure of the diamond high-pressure capsules before annealing was approximately 2.5 GPa-4 GPa. Compared to the internal pressure of conventional diamond capsules, the internal pressure of the diamond high-pressure inclusions prepared using the preparation method of the present application can be increased by 2-8 times. These results demonstrate that the internal pressure of the diamond high-pressure inclusions of the present application is significantly increased, achieving the encapsulation of the pressurized material under high pressure and maintaining the internal high pressure for a long time. This allows for in-situ measurement of the pressurized material under high pressure, facilitating the study of the properties of the pressurized material in the high-pressure phase.

[0078] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A diamond high-pressure inclusion, comprising a composite material and diamond encapsulating the composite material, wherein the composite material comprises a pressure-bearing material and a low-pressure phase pressurizing agent, wherein the pressurizing agent is selected from at least one of SiO2 and GeO2, and the pressure-bearing material is selected from at least one of a metal element, a metal oxide, a non-metal element, and a ceramic material.

2. The diamond high-pressure inclusion according to claim 1, wherein: The pressurizing agent and the pressurized material are mixed with each other, or the pressurizing agent is coated on the surface of the pressurized material to form a core-shell structure.

3. The diamond high-pressure inclusion according to claim 1, wherein: The metal element is selected from at least one of platinum, gold, rhenium, and iron; the metal oxide is selected from at least one of aluminum oxide, zirconium oxide, and magnesium oxide; the non-metal element is selected from at least one of P and Si; and the ceramic material is selected from at least one of WC and ZrC.

4. The diamond high-pressure inclusion according to any one of claims 1 to 3, wherein: The internal pressure of the diamond high-pressure inclusion is 10 GPa-22 GPa.

5. A method for preparing a diamond high-pressure inclusion according to any one of claims 1 to 4, comprising the following steps: 1) preparing a precursor, comprising: mixing the pressurizing agent in a normal pressure phase with an object to be wrapped to obtain the precursor; or coating the pressurizing agent in a normal pressure phase on the surface of the object to be wrapped to form a core-shell structure to obtain the precursor; the object to be wrapped comprises the pressure-bearing material or a raw material for synthesizing the pressure-bearing material; 2) mixing the precursor and the carbon source at a mass ratio of 1:(5-25), and then subjecting the mixture to a high-temperature and high-pressure treatment to convert the carbon source into diamond and convert the pressurizing agent from a normal-pressure phase to a high-pressure phase, thereby obtaining a diamond high-pressure capsule; the high-temperature and high-pressure treatment is performed at a temperature of 1400° C. to 2100° C. and a pressure of 12 GPa to 30 GPa; 3) High-temperature annealing is performed on the diamond high-pressure capsule at a pressure of 0.5 GPa-6 GPa and a temperature of 800° C.-2400° C. to transform the pressurizing agent from a high-pressure phase to a low-pressure phase, thereby obtaining the diamond high-pressure inclusion.

6. The preparation method according to claim 5, wherein In step 1), the mass ratio of the pressurizing agent to the object to be wrapped is 1:(0.1-0.5).

7. The preparation method according to claim 5, wherein The method of coating the pressurizing agent in the normal pressure phase on the surface of the object to be coated to form a core-shell structure is selected from a chemical gel method or a magnetron sputtering method.

8. The preparation method according to any one of claims 5 to 7, wherein The carbon source is selected from at least one of graphite, amorphous diamond powder, onion carbon, carbon nanotubes, amorphous carbon powder, and nano diamond powder.

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