Device and method for sintering diamond carbide composite sheets and synthesizing single crystal diamond

Abstract

The present invention relates to an apparatus and method for sintering diamond carbide composite sheets and synthesizing single crystal diamond. The pyrophyllite block has through-holes for fitting carbon tubes and conductive steel rings. The carbon tubes are installed within the pyrophyllite block, which are then fitted with salt tubes. A metal cup containing a carbide base and diamond powder is placed within the salt tubes, with salt sheets encapsulated at the upper and lower ports. The carbon sheets and conductive steel rings are installed at the upper and lower ends of the pyrophyllite through-holes, and the carbon sheets, salt tubes, and salt sheets are bonded to each other. The conductive steel rings have through-holes for fitting ceramic insulating cups and ceramic heat-insulating sheets. The ceramic insulating cups are installed within the pyrophyllite block, and a synthesis column for synthesizing single crystal diamond is installed within the ceramic insulating cups. The ends of the ceramic insulating cups are encapsulated with ceramic heat-insulating sheets. The synthesis column is composed of a mixture of high-purity graphite and three-element metal powders of Fe, Ni, and Co. The high temperature within the pyrophyllite block during sintering the diamond carbide composite sheet is utilized to transfer heat upward and downward to the upper and lower conductive steel rings, so that the synthesis column meets the conditions for synthesizing single crystal diamond, thereby synthesizing single crystal diamond.

Description

Technical Field

[0001] The invention relates to a high-temperature and high-pressure synthesis device for sintering diamond carbide composite sheets and simultaneously synthesizing single-crystal diamond and a synthesis process thereof. Background Art

[0002] Diamond carbide composite sheets are made by sintering diamond powder and a carbide base under high temperature and high pressure conditions. The upper part is a diamond layer and the lower part is a carbide base. They have the high hardness and high wear resistance of diamond and the impact resistance of carbide. They are used to manufacture diamond drill bits and are applied in the exploration and mining of oil, natural gas and shale gas.

[0003] Single crystal diamonds have a wide range of industrial uses, such as mining, building material cutting, building material surface polishing, mechanical cutting, grinding, and polishing of hard materials. In the industrialized artificial diamond industry, single crystal diamond output accounts for more than 90% of the total output.

[0004] At present, different devices and processes are used to produce diamond carbide composite sheets and single crystal diamonds, resulting in high preparation costs. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a device and method for sintering diamond carbide composite sheets and synthesizing single crystal diamonds.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] The invention relates to a device for sintering diamond carbide composite sheets and synthesizing single crystal diamond, which is characterized by comprising pyrophyllite, salt tubes and carbon tubes. The pyrophyllite has through holes for fitting carbon tubes and conductive steel rings, carbon tubes are installed in the pyrophyllite, salt tubes are installed in the carbon tubes, a metal cup equipped with a carbide base and diamond micropowder is placed in the salt tubes, and salt sheets are encapsulated in the upper and lower ports. Carbon sheets and conductive steel rings are installed at the upper and lower ends of the through holes of the pyrophyllite, and the carbon sheets fit the carbon tubes, salt tubes and salt sheets. The conductive steel ring has a through hole for fitting ceramic insulating cups and ceramic thermal insulation sheets, ceramic insulating cups are installed in the conductive steel rings, a synthetic column for synthesizing single crystal diamonds is installed in the ceramic insulating cups, and ceramic thermal insulation sheets are encapsulated at the ports of the ceramic insulating cups.

[0008] Furthermore, the above-mentioned sintered diamond carbide composite sheet is combined into a single crystal diamond device, wherein the conductive steel ring is made of A3 steel, 45 steel, GCr12 steel or 304 stainless steel.

[0009] Furthermore, in the above-mentioned sintered diamond carbide composite sheet and synthesized single crystal diamond device, the electrical insulation performance of the ceramic insulating cup is the same as the electrical insulation performance of the ceramic thermal insulation sheet.

[0010] Furthermore, in the above-mentioned sintered diamond carbide composite sheet and synthesized single crystal diamond device, the material of the ceramic insulating cup is BeO ceramic, BN ceramic, MgO ceramic or AlN ceramic.

[0011] Furthermore, the above-mentioned sintered diamond carbide composite sheet is synthesized into a single crystal diamond device, wherein the material of the ceramic thermal insulation sheet is Al2O3 ceramic, SiC ceramic, Si3N4 ceramic or ZrO2 ceramic.

[0012] Furthermore, the above-mentioned sintered diamond carbide composite sheet and synthesized single crystal diamond device, wherein the synthetic column is composed of a mixture of graphite and Fe, Ni, and Co three-element metal powders. Graphite is a precursor of single crystal diamond, which is converted into single crystal diamond under high temperature and high pressure under the catalysis of Fe, Ni, and Co three-element metals.

[0013] The method of sintering diamond carbide composite sheets and synthesizing single crystal diamonds is characterized by:

[0014] The diamond powder is purified with acid and alkali, the surface of the cemented carbide base is sandblasted to remove impurities, the purified cemented carbide base and diamond powder are placed in a metal cup, the metal cup containing the cemented carbide base and diamond powder is placed in a vacuum furnace for high-temperature purification, the purified metal cup is covered with a cover cup, a synthetic block is placed in the cup, and the synthetic block is placed in a six-sided top press for high-temperature and high-pressure sintering; high pressure is transmitted through pyrophyllite, and current is transmitted to the carbon sheet and carbon tube through upper and lower conductive steel rings, causing them to heat up, heating the salt tube and high-melting-point metal cup to 1500-1600°C, so that the diamond powder and cemented carbide base encapsulated by the high-melting-point metal cup are sintered in a high-temperature and high-pressure environment at a temperature of 1500-1600°C and a pressure of 5.5-7GPa;

[0015] While sintering the diamond carbide composite sheet, the high temperature of 1500-1600℃ in the pyrophyllite is transferred upward and downward to the upper and lower conductive steel rings, so that the synthetic columns in the conductive steel rings meet the conditions for synthesizing single crystal diamond, thereby synthesizing single crystal diamond.

[0016] Furthermore, in the above-mentioned method of sintering diamond carbide composite sheets and synthesizing single-crystal diamond, the synthetic column is composed of a mixture of graphite and Fe, Ni, and Co 3-element metal powders. Graphite is a precursor of single-crystal diamond, which is directly converted into single-crystal diamond under high temperature and high pressure under the catalysis of Fe, Ni, and Co 3-element metals.

[0017] Furthermore, in the above-mentioned method of sintering diamond carbide composite sheets and synthesizing single crystal diamond, the single crystal diamond is synthesized under high temperature and high pressure conditions of 1400-1480°C and 4.5-5.5GPa.

[0018] Furthermore, in the above-mentioned method of sintering diamond carbide composite sheets and synthesizing single crystal diamond, the diamond carbide composite sheets are sintered under high temperature and high pressure conditions of 1500-1600° C. and 5.5-6.5 GPa.

[0019] Compared with the prior art, the present invention has significant advantages and beneficial effects, which are specifically reflected in the following aspects:

[0020] The present invention makes full use of the volume of an annular conductive steel ring to house a synthetic column used for synthesizing single-crystal diamond. The synthetic column is composed of a mixture of high-purity graphite and three-element metal powders of Fe, Ni and Co. The high temperature of 1500-1600°C inside the pyrophyllite block during sintering of the diamond carbide composite sheet is utilized to transfer heat upward and downward to the upper and lower conductive steel rings, so that the synthetic column inside the conductive steel ring meets the conditions for synthesizing single-crystal diamond, thereby synthesizing single-crystal diamond. In addition to producing the diamond carbide composite sheet, commercially valuable single-crystal diamond is also produced.

[0021] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the specific embodiments of the present invention. The purposes and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 : Schematic diagram of the cross-sectional structure of the device of the present invention;

[0024] Figure 2 : Schematic diagram of the cross-sectional structure of the conductive steel ring;

[0025] Figure 3 : A comparative schematic diagram of the output of one sintering cycle of Examples 1 to 3. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0027] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, directional terms and order terms are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0028] like Figures 1-2 As shown, a device for sintering diamond carbide composite sheets and synthesizing single crystal diamonds comprises pyrophyllite 1, salt tubes 6 and carbon tubes 5. The pyrophyllite 1 has a through hole for fitting the carbon tubes 5 and the conductive steel ring 2. The carbon tubes 5 are installed therein. The salt tubes 6 are installed in the carbon tubes 5. A metal cup 7 equipped with a carbide base and diamond powder is placed in the salt tube 6. The upper and lower ports are encapsulated with salt sheets 4. The upper and lower ends of the through hole of the pyrophyllite 1 are loaded with carbon sheets 3 and the conductive steel ring 2. The carbon sheets 3 fit the carbon tubes 5, salt tubes 6 and salt sheets 4. The conductive steel ring 2 has a through hole for fitting a ceramic insulating cup 8 and a ceramic thermal insulation sheet 10. The ceramic insulating cup 8 is installed therein. A synthesis column 9 for synthesizing single crystal diamond is loaded in the ceramic insulating cup 8. The ports of the ceramic insulating cup 8 are encapsulated with ceramic thermal insulation sheets 10.

[0029] Among them, the material of the conductive steel ring 2 is A3 steel, 45 steel, GCr12 steel or 304 stainless steel, taking into full consideration its high electrical conductivity, low thermal conductivity, excellent heat resistance and ease of acquisition.

[0030] The electrical insulation performance of ceramic insulation cup 8 is the same as that of ceramic thermal insulation sheet 10. Ceramic insulation cup 8 is made of BeO ceramic, BN ceramic, MgO ceramic, or AlN ceramic, and has excellent thermal conductivity and electrical insulation properties. Ceramic thermal insulation sheet 10 is made of Al2O3 ceramic, SiC ceramic, Si3N4 ceramic, or ZrO2 ceramic, and has excellent thermal insulation and electrical insulation properties.

[0031] The synthetic column 9 is composed of a mixture of graphite and three-element metal powders of Fe, Ni, and Co. Graphite is a precursor of single-crystal diamond and is converted into single-crystal diamond under high temperature and high pressure under the catalysis of the three-element metals of Fe, Ni, and Co.

[0032] The process of producing single crystal diamond while sintering diamond carbide composite sheets is as follows:

[0033] The diamond powder is purified by acid and alkali, and the surface of the cemented carbide base is sandblasted to remove impurities. The purified cemented carbide base and diamond powder are placed in a metal cup 7. The metal cup containing the cemented carbide base and diamond powder is placed in a vacuum furnace for high-temperature purification. The purified metal cup is covered with a cover cup and loaded with a composite block. The composite block is placed in a six-sided top press for high-temperature and high-pressure sintering.

[0034] The six-sided press injects 60-100 MPa high-pressure oil into a 500-850 mm diameter oil cylinder, pushing six pistons toward the center. When the front hammer contacts the six faces of the synthetic block (hexahedron), the synthetic block is squeezed. The high pressure is transmitted through pyrophyllite, and the current is transmitted to the carbon sheet 3 and carbon tube 5 through the upper and lower conductive steel rings 2, causing them to heat up. The salt tube 6 and the high-melting-point metal cup 7 are heated to 1500-1600°C, so that the diamond powder and cemented carbide base wrapped in the high-melting-point metal cup are sintered in a high-temperature and high-pressure environment of 1500-1600°C and 5.5-7 GPa.

[0035] When sintering diamond carbide composite sheets, the high temperature of 1500-1600℃ in pyrophyllite is transferred upward and downward to the upper and lower conductive steel rings 2, so that the synthetic column 9 in the conductive steel ring 2 meets the conditions for synthesizing single crystal diamond. The synthetic column is composed of a mixture of high-purity graphite and Fe, Ni, and Co three-element metal powders. High-purity graphite is a precursor of single crystal diamond. It is directly converted into single crystal diamond under high temperature and high pressure under the catalysis of Fe, Ni, and Co three-element metals.

[0036] Preferably, single crystal diamond is synthesized under high temperature and high pressure conditions of 1400-1480° C. and 4.5-5.5 GPa, and the temperature and pressure are obtained from the synthesis block while sintering the diamond carbide composite sheet.

[0037] Preferably, the diamond carbide composite sheet is sintered under high temperature and high pressure conditions of 1500-1600° C. and 5.5-6.5 GPa.

[0038] Example 1

[0039] Using the current technology for sintering diamond carbide composite sheets, the conductive steel ring is filled with pyrophyllite powder and maintained at 1500℃ and 6.0GPa high temperature and high pressure conditions for 350 to 400 seconds, producing two composite sheets in one sintering cycle.

[0040] Example 2

[0041] The conductive steel ring structure of the present invention features through-holes for mounting a ceramic insulating cup and a ceramic thermal insulation sheet. The ceramic insulating cup is mounted within the conductive steel ring, which contains a synthetic column for synthesizing single-crystal diamond. The conductive steel ring measures 42 to 36 x 12 mm and is made of 45-grade steel. The single-crystal diamond column measures 33 x 8.5 mm. The ceramic insulating cup has an outer diameter of 36 mm, an inner diameter of 33 mm, a bottom thickness of 1.5 mm, and an outer height of 10 mm, and is made of BO. The ceramic thermal insulation sheet measures 36 x 2 mm and is made of SiC.

[0042] The high-temperature and high-pressure conditions for sintering diamond carbide composite sheets are 1500°C and 6.0 GPa for 380 seconds. During this time, the required high temperature and pressure are transmitted to the conductive steel ring, and the single-crystal diamond composite column is subjected to an environment of 1400-1480°C and 4.5-5.5 GPa for 380 seconds, converting the high-purity graphite powder in the composite column into single-crystal diamond. One sintering cycle yields two composite sheets and 23-26 carats of single-crystal diamond.

[0043] Example 3

[0044] The conductive steel ring structure of the present invention features through-holes for mounting a ceramic insulating cup and a ceramic thermal insulation sheet. The ceramic insulating cup is mounted within the conductive steel ring, which contains a synthetic column for synthesizing single-crystal diamond. The conductive steel ring measures 42 to 39 x 12 mm and is made of 304 stainless steel. The single-crystal diamond column measures 37 x 9.0 mm. The ceramic insulating cup has an outer diameter of 39 mm, an inner diameter of 37 mm, a bottom thickness of 1.0 mm, and an outer height of 10 mm, and is made of BN. The ceramic thermal insulation sheet measures 39 x 2 mm and is made of Si3N4.

[0045] That is, the volume of the conductive steel ring, ceramic insulating cup and ceramic thermal insulation sheet is reduced, and the effective volume of the single crystal diamond synthetic column is increased. Using the same process as Example 2, the output of one sintering cycle is 2 composite sheets and 30 to 35 carats of single crystal diamond.

[0046] like Figure 3 , a schematic diagram comparing the output of one sintering cycle of Example 1, Example 2 and Example 3; compared with Example 2, the output of single crystal diamond in Example 3 increases by 33%.

[0047] In summary, the present invention makes full use of the volume of the annular conductive steel ring to install the synthetic column used for synthesizing single-crystal diamond. The synthetic column is composed of a mixture of high-purity graphite and Fe, Ni, and Co three-element metal powders. The high temperature of 1500-1600°C inside the pyrophyllite block during sintering of the diamond carbide composite sheet is utilized to transfer heat upward and downward to the upper and lower conductive steel rings, so that the synthetic column inside the conductive steel ring meets the conditions for synthesizing single-crystal diamond, thereby synthesizing single-crystal diamond. While producing the diamond carbide composite sheet, single-crystal diamond with commercial value is also produced.

[0048] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, improvements, and the like made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention. It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it need not be further defined or explained in subsequent figures.

[0049] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0050] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

Claims

1. A device for sintering diamond carbide composite sheets and synthesizing single crystal diamonds, characterized by: The invention comprises pyrophyllite (1), salt tubes (6) and carbon tubes (5). The pyrophyllite (1) has a through hole for fitting the carbon tubes (5) and the conductive steel ring (2). The carbon tubes (5) are installed in the pyrophyllite. The salt tubes (6) are installed in the carbon tubes (5). A metal cup (7) equipped with a carbide base and diamond micropowder is placed in the salt tube (6). The upper and lower ports are encapsulated with salt sheets (4). The upper and lower ends of the through hole of the pyrophyllite (1) are loaded with carbon sheets (3) and the conductive steel ring (2). The carbon sheets (3) fit the carbon tubes (5), the salt tubes (6) and the salt sheets (4). The conductive steel ring (2) has a through hole for fitting the ceramic insulating cup (8) and the ceramic heat-insulating sheet (10). The ceramic insulating cup (8) is installed in the ceramic insulating cup. A synthetic column (9) for synthesizing single crystal diamond is loaded in the ceramic insulating cup (8). The ports of the ceramic insulating cup (8) are encapsulated with the ceramic heat-insulating sheet (10).

2. The device for sintering diamond carbide composite sheets and synthesizing single crystal diamond according to claim 1, characterized in that: The conductive steel ring (2) is made of A3 steel, 45 steel, GCr12 steel or 304 stainless steel.

3. The device for sintering diamond carbide composite sheets and synthesizing single crystal diamond according to claim 1, characterized in that: The electrical insulation performance of the ceramic insulating cup (8) is the same as that of the ceramic heat insulating sheet (10).

4. The device for sintering diamond carbide composite sheets and synthesizing single crystal diamond according to claim 1 or 3, characterized in that: The material of the ceramic insulating cup (8) is BeO ceramic, BN ceramic, MgO ceramic or AlN ceramic.

5. The device for sintering diamond carbide composite sheets and synthesizing single crystal diamond according to claim 1 or 3, characterized in that: The ceramic heat insulation sheet (10) is made of Al2O3 ceramic, SiC ceramic, Si3N4 ceramic or ZrO2 ceramic.

6. The device for sintering diamond carbide composite sheets and synthesizing single crystal diamond according to claim 1, characterized in that: The synthetic column (9) is composed of a mixture of graphite and three-element metal powders of Fe, Ni and Co. Graphite is a precursor of single crystal diamond and is converted into single crystal diamond under high temperature and high pressure under the catalysis of the three-element metals of Fe, Ni and Co.

7. A method for sintering a diamond carbide composite sheet and synthesizing a single crystal diamond using the apparatus of claim 1, characterized in that: The diamond micropowder is subjected to acid and alkali purification treatment, the surface of the cemented carbide base is sandblasted to remove impurities, the purified cemented carbide base and diamond micropowder are placed in a metal cup (7), the metal cup (7) with the cemented carbide base and diamond micropowder is placed in a vacuum furnace for high-temperature purification treatment, the purified metal cup is covered with a cover cup, a synthetic block is placed, and the synthetic block is placed in a six-sided top press for high-temperature and high-pressure sintering; the high pressure is transmitted through pyrophyllite, and the current is transmitted to the carbon sheet (3) and the carbon tube (5) through the upper and lower conductive steel rings (2), causing them to heat up, and the salt tube (6) and the high-melting-point metal cup (7) are heated to 1500-1600° C., so that the diamond micropowder and the cemented carbide base wrapped by the high-melting-point metal cup are sintered in a high-temperature and high-pressure environment with a temperature of 1500-1600° C. and a pressure of 5.5-7 GPa; The diamond carbide composite sheet is sintered at a high temperature of 1500-1600° C. in the pyrophyllite, and the heat is transferred upward and downward to the upper and lower conductive steel rings (2), so that the synthetic column (9) in the conductive steel ring (2) meets the conditions for synthesizing single crystal diamond, thereby synthesizing single crystal diamond.

8. The method for sintering a diamond carbide composite sheet and synthesizing single crystal diamond according to claim 7, characterized in that: The synthetic column (9) is composed of a mixture of graphite and three-element metal powders of Fe, Ni and Co. Graphite is a precursor of single crystal diamond and is directly converted into single crystal diamond under high temperature and high pressure under the catalysis of the three-element metals of Fe, Ni and Co.

9. The method for sintering a diamond carbide composite sheet and synthesizing single crystal diamond according to claim 7, characterized in that: Single crystal diamond is synthesized under high temperature and high pressure conditions of 1400-1480℃ and 4.5-5.5GPa.

10. The method for sintering a diamond carbide composite sheet and synthesizing single crystal diamond according to claim 7, characterized in that: The diamond carbide composite sheet is sintered under high temperature and high pressure conditions of 1500-1600°C and 5.5-6.5GPa.

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