A method for high-pressure light transmission and sealing of large-size materials

Abstract

This invention discloses a method for high-pressure transparent sealing of large-size materials, comprising: (1) establishing the sealing coordinate position of the target material and calculating the placement coordinate position of the target material; (2) synthesizing a diamond block containing the standard pressure material using diamond powder and a standard pressure material at different sintering temperatures, wherein the standard pressure material is located at the sealing coordinate position within the diamond block; (3) establishing the correlation between the sintering temperature and the pressure load located at the sealing coordinate position within the diamond cavity, and completing the diamond cavity pressure calibration; (4) calculating the sintering temperature required for the target sealing pressure, and synthesizing a diamond block encapsulating the target material at this temperature, ensuring that the target material is located at the sealing coordinate position within the diamond block, thereby achieving high-pressure transparent sealing of the material. This invention enables the detection of internal stress at any position of the transparent material, with high measurement accuracy, accurate measurement spatial position, and convenient measurement, facilitating non-destructive testing of the internal stress of the transparent material.

Description

Technical Field

[0001] This invention belongs to the field of pressure measurement, and in particular relates to a high-pressure transparent sealing method for large-sized materials. Background Technology

[0002] Pressure is one of the fundamental parameters that alters the state of matter. As a typical high-pressure system, the Earth's core undergoes successive phase transitions with increasing depth and pressure, forming new phases with drastically different structures and properties. Some substances exhibit reversible phase transitions due to pressure, making it difficult to directly observe their high-pressure phases under normal atmospheric pressure. Therefore, preserving these reversible high-pressure phases under normal atmospheric pressure and enabling phase analysis is crucial for revealing the composition of the Earth's core and simulating geodynamics.

[0003] Currently, high pressure generation methods are limited to two types: diamond anvil cells and large-cavity presses. While diamond anvil cells can impart very high pressure to materials, they have strict limitations on the size of the pressurized material (micrometer scale). Large-cavity presses encapsulate materials within pressure-transmitting media such as pyrophyllite and dolomite, achieving the construction of millimeter- to centimeter-scale high-pressure media through external loads. However, because the pressure-transmitting media is completely sealed and opaque, in-situ detection of high-pressure phase transitions in materials is impossible. Therefore, the search for a high-pressure, transparent, and light-transmitting method for the preservation of large-size materials is urgently needed.

[0004] Studies have shown that high-pressure, light-transmitting sealing of large-volume materials requires meeting fundamental conditions such as a large-cavity pressure environment, controllable cavity pressure, uniform material pressure, and good light transmittance of the pressure-transmitting medium, posing significant engineering challenges. Diamond materials possess advantages such as large volume (millimeters to sub-centimeter scale), good light transmittance, and high internal stress. Using diamond as the pressure-generating medium and sealing cavity provides a feasible approach for high-pressure, light-transmitting sealing of large-volume materials.

[0005] Chinese patent document with application number CN201811545952.6 discloses a high-pressure in-situ measurement device and method for measuring phase transition of metallic material structure using microwave. It uses a diamond anvil cell to generate a high-pressure environment and calculates the microwave power to obtain the phase transition of the sample structure.

[0006] Chinese patent document with application number CN201510195009.7 discloses a method for measuring phase transitions of matter under static high pressure. It uses a diamond anvil cell to generate a high-pressure environment and uses short-wavelength X-ray diffraction to measure the high-pressure structural phase transition of the matter.

[0007] However, none of the above methods mention how to perform high-pressure light transmission sealing for large-sized materials. Summary of the Invention

[0008] This invention provides a high-pressure transparent sealing method for large-size materials, which enables the detection of internal stress at any position of the transparent material. It features high measurement accuracy, accurate measurement spatial position, and convenient measurement, facilitating non-destructive testing of internal stress in transparent materials.

[0009] A method for high-pressure, light-transmitting sealing of large-size materials includes the following steps:

[0010] (1) Establish the sealing coordinate position of the target sealed material and calculate the placement coordinate position of the target sealed material; where the placement coordinate position refers to the position where the target sealed material is placed in the diamond powder, and the sealing coordinate position refers to the position of the target sealed material at the placement coordinate position after the diamond powder is sintered, due to the shrinkage of the diamond volume.

[0011] (2) At different sintering temperatures, diamond powder and standard pressure material are used to synthesize diamond blocks containing standard pressure material, wherein the standard pressure material is located at the sealing coordinate position inside the diamond block.

[0012] (3) Establish the correlation between the sintering temperature and the pressure load located at the sealing coordinate position in the diamond cavity, and complete the pressure calibration of the diamond pressure cavity;

[0013] (4) Calculate the sintering temperature required for the target sealing pressure, and synthesize a diamond block to encapsulate the target sealing material at this temperature, ensuring that the target sealing material is located at the sealing coordinate position inside the diamond block, and finally achieve high-pressure light-transmitting sealing of the material.

[0014] In the technical solution of this invention, the target material is encapsulated in diamond micropowder and sintered under high temperature and high pressure to form a diamond block encapsulating the target material; the large-volume diamond block is used as a pressure chamber, and the internal stress of the diamond is used as a pressure source to construct a high-pressure environment with the diamond as the cavity; by adjusting the sintering thermodynamic conditions of the diamond, the internal sealing pressure of the diamond is adjusted to achieve precise control of the internal pressure level of the diamond; the synthesized diamond has good light transmittance, which facilitates the use of optical measuring instruments to detect and analyze the high-pressure phase transition of the target material.

[0015] In this invention, large-size materials refer to materials with sizes ranging from millimeters to subcentimeters.

[0016] The specific process of step (1) is as follows:

[0017] Let the origin o be any position on the diamond surface, and establish a spatial rectangular coordinate system oxyz; under the established oxyz rectangular coordinate system, the sealing coordinate position of the target sealed material is P, and the corresponding coordinates are (x... P ,y P ,z P );

[0018] Diamond powder was pre-pressed into a high-pressure sintering unit. The volume of diamond powder V1 within the high-pressure sintering unit and the volume of diamond after sintering V2 were measured using Archimedes' displacement method. The shrinkage rate of diamond A after sintering was calculated.

[0019] The target encapsulated material is placed in diamond powder at coordinate P. f The corresponding coordinates are (X P ,Y P Z P ); where X P =x P / α, Y P =y P / α,Z P =z P / α;

[0020] After the diamond powder is sintered, it is located at the placement coordinate position P. f The target material to be sealed changes to the sealing coordinate position P due to the shrinkage of the diamond.

[0021] In step (2), the specific process for synthesizing the diamond bulk containing the standard pressure material is as follows:

[0022] Diamond powder and the standard pressure material were treated with anhydrous ethanol, and the waste liquid was poured out and dried. The standard pressure material was then encapsulated within the diamond powder, ensuring that the standard pressure material was positioned at coordinate P. f The high-pressure sintering unit is pre-pressed and formed into a high-pressure sintering unit, which is then placed into the synthesis chamber of the high-pressure equipment for sintering.

[0023] The sintering process is as follows: pressurize to the set sintering pressure p, and after reaching the set pressure, heat to the sintering temperature T and hold at that temperature for a period of time t; after the holding period, stop heating and reduce the pressure.

[0024] Preferably, the diamond powder has a size of 3nm-500μm and the volume of the standard pressure material is 13mm.

[0025] Preferably, the standard pressure material is one of Pt, Au, or ruby.

[0026] Preferably, the sintering pressure p = 20 GPa, the sintering temperature T = 100-2300℃, and the holding time t = 20 min.

[0027] Preferably, the high-pressure equipment is a domestically produced six-sided top press.

[0028] The specific process of step (3) is as follows:

[0029] Following the method in step (2), diamond blocks encapsulating standard pressure materials were synthesized at target sintering pressure p0, target holding time t0, and different sintering temperatures T; and a set {T} was set for different sintering temperatures T. i}, set at sintering temperature T i The diamond block containing the standard pressure material is called standard pressure block A. i Where i = 1, 2, 3, ..., n;

[0030] The pressure gauge block A was obtained using an optical measuring instrument. i The spectrum of the internal standard pressure substance, corresponding to the shift peak position is: The spectrum of the standard pressure substance was measured using an optical measuring instrument, and the original peak position was identified as l2. Therefore, the standard pressure block A... i Pressure load p at coordinate position P of the internal sealing Pi for

[0031]

[0032] Where β is the linear shift of the original peak value of the standard pressure substance under unit pressure, i = 1, 2, 3, ..., n; and the pressure load p is set. Pi The set is {p Pi};

[0033] Set the sintering temperature T and the pressure load p P The relationship between them is:

[0034]

[0035] Among them, b j The parameter is to be determined; set the parameter to be determined b. j Form the set of undetermined parameters {b j}, j = 0, 1, 2, 3; by {T i} as the independent variable, {p Pi} as the dependent variable, in the formula As a functional expression, the set of undetermined parameters {b} is obtained by polynomial fitting. i}

[0036] In step (4), the target sealing pressure is p. P0 Through formula Calculate the required target sintering temperature T0; following the method in step (2), place the coordinates at position P. f The target encapsulation material is placed at the target location, and a diamond block containing the target encapsulation material is prepared under the sintering conditions of target sintering pressure p0, target holding time t0, and target sintering temperature T0.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. This invention uses the internal stress of diamond as a pressure source to replace the traditional external pressure method, effectively solving the spatial interference problem between large external pressure devices and material performance testing instruments, and is easy to carry.

[0039] 2. This invention uses large-volume diamond as the pressure chamber, with a chamber capacity reaching the millimeter level, which significantly expands the application range of high-pressure phase change detection materials.

[0040] 3. This invention achieves precise control of the internal pressure of the cavity by adjusting the sintering thermodynamic load of diamond.

[0041] 4. The diamond cavity prepared by this invention has light transmittance, which supports in-situ detection of the high-pressure phase transition of the internal test material by optical measuring instruments. Attached Figure Description

[0042] Figure 1 This is a flowchart of a high-pressure transparent light-transmitting method for storing large-size materials according to the present invention;

[0043] Figure 2 This is a schematic diagram showing the coordinates of the sealing location in an embodiment of the present invention;

[0044] Figure 3 This is a schematic diagram showing the coordinate positions of the standard pressure material in an embodiment of the present invention;

[0045] Figure 4 This is a schematic diagram of diamond internal pressure calibration in an embodiment of the present invention; Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments are for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0047] In this embodiment of the invention, the target material 2 to be sealed is bismuth (Bi 0.125mm). 3 (Spherical), target pressure p P0 The standard pressure was 2.6 GPa. The synthesized diamond 1 was a cylinder, 3 mm high and 2 mm in diameter. The standard pressure material 4 was a ruby ​​sphere, approximately 0.125 mm in size. 3 .

[0048] like Figure 1 As shown, a method for high-pressure light transmission and sealing of large-size materials includes:

[0049] Step 1: Establish the sealing coordinates and calculate the placement coordinates of the sealed material.

[0050] like Figure 2 As shown, a spatial rectangular coordinate system oxyz is established for diamond 1. The origin o is set at the edge of the lower surface of the diamond 1 cylinder; the x-axis is the direction of the line connecting the origin o to the center of the lower surface of diamond 1; the z-axis is parallel to the axis of the diamond 1 cylinder and points towards the upper surface of the diamond 1 cylinder; the y-axis is orthogonal to the x and z directions, ensuring that the spatial rectangular coordinate system oxyz conforms to the right-hand rule.

[0051] Under the established rectangular coordinate system, the sealing coordinate position P of the target sealed material 2 is (1,0,1.5).

[0052] Diamond powder (98% purity, average grain size 15μm) was pre-pressed into high-pressure sintering unit 3. For example... Figure 3 As shown, V1 is the volume of diamond 1 powder in high-pressure sintering unit 3, and V2 is the volume of diamond 1 after sintering.

[0053] The volume of diamond 1 powder contained in high-pressure sintering unit 3 was measured using Archimedes' displacement method, V1 = 10.467 mm. 2 After synthesizing diamond 1, the volume of diamond 1 was measured to be V2 = 9.42 mm. 2 The shrinkage rate of diamond 1 after sintering was calculated as follows:

[0054]

[0055] The target sealed material 2 is placed in the diamond 1 powder at coordinate P. f The corresponding coordinates are (X P ,Y P Z P ), where X P =1 / 0.9=1.11, Y P =0 / 0.9=0, Z P =1.5 / 0.9 = 1.67. After the diamond 1 powder is sintered, it is located at the placement coordinate position P. f The target sealed material 2 changes to the sealed coordinate position P due to the contraction of diamond 1.

[0056] Step 2, diamond compression molding.

[0057] Diamond powder (15 μm grain size) and standard pressure material (4) were treated with anhydrous ethanol. After the waste liquid was drained, the powder was dried at 100°C. Standard pressure material 4 was then encapsulated within the diamond powder, ensuring it was positioned at coordinate P. f(1.11,0,1.67), and pre-pressed into high-pressure sintering unit 3. The high-pressure sintering unit 3 is then placed in the synthesis chamber of a domestic six-sided constant pressure press for sintering.

[0058] The sintering process is as follows: pressurize to the set target sintering pressure p0 = 20 GPa, and after reaching the set pressure, heat to the sintering temperature T = 1200℃-1800℃, hold for a period of time t0 = 20 min; after the holding period, stop heating and reduce the pressure.

[0059] Step 3: Pressure calibration of the diamond pressure chamber.

[0060] Following the method in step 2, diamond blocks encapsulating the standard pressure material 4 were synthesized at a target sintering pressure p0 = 20 GPa, a target holding time t0 = 20 min, and different sintering temperatures of 1200℃, 1400℃, 1600℃, and 1800℃. The set of different sintering temperatures T was defined as {1200, 1400, 1600, 1800}. The diamond blocks encapsulating the standard pressure material 4 synthesized at sintering temperatures of 1200℃, 1400℃, 1600℃, and 1800℃ were designated as standard pressure blocks A1, A2, A3, and A4.

[0061] like Figure 4 As shown, l1 represents the offset peak position of the standard pressure substance 4 at the target sealing position P on diamond 1 measured by an optical measuring instrument, and l2 represents the original peak position of the standard pressure substance 4 measured by an optical measuring instrument.

[0062] The spectra of standard pressure substance 4 within standard pressure blocks A1, A2, A3, and A4 were obtained using an X-ray diffractometer. The corresponding shift peak positions are as follows: The spectrum of the standard pressure substance 4 was measured using an X-ray diffractometer, and the corresponding original peak position was l2 = 694.2 nm. Therefore, the pressure load at coordinate position P within the standard pressure blocks A1, A2, A3, and A4 is...

[0063] p P1 =|(694.2-694.4263)|×2.74=0.62GPa

[0064] p P2 =|(694.2-694.9117)|×2740=1.95GPa

[0065] p P3 =|(694.2-695.1708)|×2.74=2.66GPa

[0066] p P4 =|(694.2-695.273)|×2.74=2.94GPa

[0067] Pressure load p Pi The set consists of {0.62, 1.95, 2.66, 2.94}.

[0068] Set the sintering temperature T and the pressure load p P The relationship between them is:

[0069]

[0070] By using the sintering temperature T as the independent variable and the pressure load p P As the dependent variable, the formula As a functional expression, the polynomial fitting method is used to find the set of undetermined parameters {b}. j} is {3.958×10 -9 -2.4375×10 -5 4.9917×10 -2 ,-31.02}.

[0071] formula The expression is:

[0072] p P (T) = 3.958 × 10 -9 ×T 3 -2.4375×10 -5 ×T 2 +4.9917×10 -2 ×T-31.02

[0073] Step 4: High-pressure light transmission and sealing of large-sized materials under target pressure.

[0074] The target pressure for storage is p P0 =2.6 GPa, through the formula The required target sintering temperature is calculated to be T0 = 1577℃.

[0075] Following the method in step 2, place the coordinates at position P. f The target encapsulation material 2 was placed in a suitable location, and diamond 1 containing the target encapsulation material 2 was prepared under the conditions of target sintering pressure p0 = 20GP, target holding time t0 = 20min, and target sintering temperature T0 = 1577℃. High-pressure light-transmitting encapsulation of the target encapsulation material 2 was achieved.

[0076] The method of this invention uses a large-volume diamond block as a pressure chamber and the internal stress of the diamond as a pressure source to construct a high-pressure environment with the diamond as the chamber; the internal pressure level of the diamond is precisely controlled by adjusting the sintering parameters of the diamond; the synthesized diamond has light transmittance, which facilitates the use of optical measuring instruments to detect and analyze the high-pressure phase transition of the target material.

[0077] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, and equivalent substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-pressure light-transmitting encapsulation method for large-size substances, characterized by, Includes the following steps: (1) Establish the sealing coordinate position of the target sealed material and calculate the placement coordinate position of the target sealed material; where the placement coordinate position refers to the position where the target sealed material is placed in the diamond powder, and the sealing coordinate position refers to the position of the target sealed material at the placement coordinate position after the diamond powder is sintered, due to the shrinkage of the diamond volume. (2) At different sintering temperatures, diamond powder and standard pressure material are used to synthesize diamond blocks containing standard pressure material, wherein the standard pressure material is located at the sealing coordinate position inside the diamond block; (3) Establish the correlation between the sintering temperature and the pressure load located at the sealing coordinate position inside the diamond cavity, and complete the pressure calibration of the diamond cavity; the specific process is as follows: According to the method of step (2), the target sintering pressure is p0, the target holding time is t0, and different sintering temperatures T The diamond block containing the marker pressure substance is synthesized, and different sintering temperatures T Set of compositions { T i} at a sintering temperature T i The diamond block containing the marker pressure substance synthesized below is a marker pressure block A i ; wherein i = 1, 2, 3, …, n ; Obtaining the standard pressure block using optical measuring instruments A i The spectrum of the internal standard pressure substance, corresponding to the shift peak position is: The spectrum of the standard pressure substance was measured using an optical measuring instrument, and the corresponding original peak position was... Then the standard pressure block A i Internal storage coordinates P Pressure load at the location for in, This represents the linear shift of the original peak value of the standard pressure substance under unit pressure. i =1, 2, 3, …, n Set pressure load The set is { }; Set sintering temperature T With pressure load The relationship between them is: in, b j For parameters to be determined; set parameters to be determined b j Form a set of undetermined parameters { b j }, j =0, 1, 2, 3; by { T i } as the independent variable, { } as the dependent variable, in the formula As a functional expression, the set of undetermined parameters is obtained by polynomial fitting. b j }; (4) Calculate the sintering temperature required for the target sealing pressure, and synthesize a diamond block to encapsulate the target sealing material at this temperature, ensuring that the target sealing material is located in the sealing coordinate position within the diamond block, and finally achieve high-pressure light-transmitting sealing of the material.

2. The method for high-pressure light transmission and sealing of large-size materials according to claim 1, characterized in that, The specific process of step (1) is as follows: Set origin o Establish a spatial rectangular coordinate system at any position on the diamond surface as follows: In establishing In a rectangular coordinate system, the storage coordinates of the target material are: P The corresponding coordinates are ; Diamond powder was pre-pressed into a high-pressure sintering unit. The volume of diamond powder V1 within the high-pressure sintering unit and the volume of diamond after sintering V2 were measured using Archimedes' displacement method. The shrinkage rate of diamond A after sintering was calculated. ; The placement coordinates of the target encapsulated material in the diamond powder are: The corresponding coordinates are ;in, , , ; After the diamond powder is sintered, it is located at the placement coordinate position. The target sealed material changes its sealed coordinate position due to the volume shrinkage of the diamond. P .

3. The method for high-pressure light transmission and sealing of large-size materials according to claim 1, characterized in that, In step (2), the specific process for synthesizing the diamond bulk containing the standard pressure material is as follows: Diamond powder and the standard pressure material were treated separately with anhydrous ethanol, and the waste liquid was poured out and dried. The standard pressure material was then encapsulated within the diamond powder, ensuring that the standard pressure material was positioned at the designated coordinate location. The high-pressure sintering unit is pre-pressed and formed into a high-pressure sintering unit, which is then placed into the synthesis chamber of the high-pressure equipment for sintering. The sintering process is as follows: pressurize to the set sintering pressure. p After reaching the set pressure, the temperature is increased to the sintering temperature. T Keep warm for a period of time t After the heat preservation is completed, stop heating and reduce the pressure.

4. The method for high-pressure light transmission and sealing of large-size materials according to claim 1 or 3, characterized in that, In step (2), the size of the diamond powder is 3 nm to 500 μm, and the volume of the marker substance is 1 mm 3 .

5. The method for high-pressure light transmission and sealing of large-size materials according to claim 1 or 3, characterized in that, In step (2), the standard pressure substance is one of Pt, Au, or ruby.

6. The method for high-pressure light transmission and sealing of large-size materials according to claim 3, characterized in that, Sintering pressure p =20GPa, sintering temperature T =100-2300 ℃, heat preservation time t =20 min.

7. The method for high-pressure light transmission and sealing of large-size materials according to claim 1, characterized in that, In step (4), the target pressure for sealing is Through formula Calculate the required target sintering temperature T0; following the method in step (2), place the coordinates at the desired location. The target encapsulation material is placed at the target location, and a diamond block containing the target encapsulation material is prepared under the sintering conditions of target sintering pressure p0, target holding time t0, and target sintering temperature T0.

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