Graphite column for diamond synthesis, assembly block and graphite column manufacturing method

Abstract

The present invention relates to a diamond synthesis assembly block in the field of diamond synthesis equipment technology, comprising a pyrophyllite block, a vertical cylindrical through hole is provided in the center of the pyrophyllite block, an alumina insulation layer is provided on the side wall of the cylindrical through hole, a conductive cylinder is sleeved in the cylindrical through hole, and conductive sheets are provided at both ends of the conductive cylinder, an alumina ring is provided on the conductive sheet, a pyrophyllite ring is matched on the alumina ring, a circle of grooves 1 is provided on the surface of the pyrophyllite ring corresponding to the alumina ring, a circle of protrusions matching the grooves 1 is provided on the alumina ring, and the pyrophyllite ring is matched with a conductive steel ring; the pyrophyllite ring matched with the conductive steel ring of the present invention is perfectly matched with the alumina ring, so that the pressure can be effectively transmitted from the upper and lower ends to the inside, so that the pressure difference between the two ends and the middle is as small as possible. High-temperature sintered alumina powder is used as the insulation layer, which improves the insulation effect, reduces the temperature difference, and the sintered alumina has less volatile impurities, further improving the quality of diamonds.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond synthesis equipment, and in particular relates to a graphite column and an assembly block for diamond synthesis, and a method for manufacturing the graphite column. Background Art

[0002] There are two methods for synthesizing diamond: high temperature and high pressure method and CVD thin film precipitation method. In China, the main method is to use a six-sided top press at 1450°C and 5.3GPa pressure to achieve the transformation from graphite powder to diamond by increasing the density. In this synthesis process, the structure of the core assembly block is very important. In the prior art, conventional assembly blocks use indirect heating to save current, use dolomite for heat preservation, use flat packaging in the heating direction, and use arched support in the non-heating direction. However, dolomite has poor thermal insulation effect, is easy to decompose and produce carbon dioxide under high temperature and high pressure, which is not conducive to the synthesis effect, and contains more impurities, affecting the quality of diamond; the heating direction is flat, and the non-heating direction is supported by an arch, and the pressure transmission effect is different. After being heated by pressure, the two ends shrink rapidly, causing the heating direction to be hollow, and it is easy to lose balance and blast. It cannot solve the temperature difference and pressure difference problems in the spatial structure well, and the pressure cannot be well transmitted to the internal cavity. The product quality is low in the proportion of excellent crystals, the magnetism is high, and the slag removal is slow. Therefore, a graphite column, assembly block, and graphite column manufacturing method for diamond synthesis are needed to solve the above problems. Summary of the invention

[0003] In view of the above-mentioned defects in the prior art, the present invention provides a graphite column for diamond synthesis, the graphite column includes three parts, an upper column, a middle column and a lower column connected in sequence, the outer side of the top of the upper column is an upward convex arc, the bottom of the upper column is provided with a second groove, the second groove is a tapered groove narrow at the top and wide at the bottom, the upper column and the lower column are symmetrical up and down, the top of the middle column matches the bottom of the upper column, and the bottom of the middle column matches the top of the lower column. The arc-shaped arrangement of the upper and lower ends of the graphite column can effectively transfer the pressure from the two ends to the center of the column core, and at the same time, the middle column is connected with the upper column and the lower column using tapered grooves to lock together so that the pressure can be evenly and effectively transferred to the center, which can greatly improve the product output and quality.

[0004] Preferably, the central angle of the arc on the outer side of the top of the upper cylinder is 15 degrees.

[0005] The present invention also discloses a method for manufacturing a graphite column for diamond synthesis, which at least comprises the following steps:

[0006] Step 1: mixing graphite powder and catalyst powder;

[0007] Step 2: forming, pressing the mixed materials in step 1 into upper cylinder, middle cylinder and lower cylinder in corresponding molds;

[0008] Step 3: sintering: placing the upper cylinder, middle cylinder and lower cylinder pressed in step 2 into a sintering furnace for sintering;

[0009] Step 4: assemble, stack the sintered lower cylinder, middle cylinder and upper cylinder together in sequence.

[0010] Preferably, the catalyst powder is iron-nickel alloy catalyst powder.

[0011] The present invention also discloses a diamond synthesis assembly block, comprising a pyrophyllite block and a graphite column, wherein the graphite column is the above-mentioned graphite column for diamond synthesis, wherein a vertical cylindrical through hole is provided at the center of the pyrophyllite block, an alumina thermal insulation layer is provided on the side wall of the cylindrical through hole, a conductive cylinder is sleeved in the cylindrical through hole, conductive sheets are provided at both upper and lower ends of the conductive cylinder, an alumina ring is provided on the conductive sheet, a pyrophyllite ring is matched with the alumina ring, a circle of grooves one is provided on the surface of the pyrophyllite ring corresponding to the alumina ring, a circle of protrusions matching the groove one is provided on the alumina ring, and the pyrophyllite ring is matched with a conductive steel ring; the pyrophyllite ring matched with the conductive steel ring and the alumina ring have one protrusion and one concave, and the combined parts are perfectly matched, so that the pressure can be effectively transmitted from the upper and lower ends of the assembly block to the inside, so as to achieve the purpose of minimizing the pressure difference between the two ends and the middle. The alumina ring and alumina insulation layer are made of sintered alumina powder. The high-temperature sintered alumina powder is used as the insulation layer to improve the insulation effect. The sintered alumina has less volatile impurities, which further improves the quality of the diamond. That is, the two ends and the outer insulation layer use alumina treated at 1650℃, which does not contain impurities and gas, has high density, good pressure transmission, good insulation effect, reduces axial and radial temperature differences, and effectively improves product quality. The pyrophyllite ring and alumina ring at both ends of the combined block are connected by a snap-on buckle, which can transmit the pressure from the top hammer without loss, making the entire pressure field of the composite block more uniform.

[0012] The graphite column is arranged in the conductive cylinder, and an iron cup and an insulating bowl are arranged in sequence outside the graphite column in the conductive cylinder.

[0013] Preferably, the pyrophyllite block, alumina insulation layer, iron cup and insulating bowl are all composed of two parts that are separated and symmetrical from top to bottom.

[0014] The devices or components not limited in the present invention all adopt conventional technical means in the field, such as pyrophyllite rings, alumina rings, iron cups, insulating bowls, conductive steel rings, etc., which are all conventional equipment in the field.

[0015] The beneficial effects of the present invention are as follows: 1. The thermal insulation layer of the assembly block is made of alumina powder sintered at high temperature to replace the traditional dolomite, which greatly increases the thermal insulation effect. The sintered alumina has less volatile impurities, which improves the quality of diamonds. 2. The phyllite ring and the alumina ring matched with the conductive steel ring are one convex and one concave, and the joint parts are perfectly matched, which can effectively transfer the pressure from the upper and lower ends of the assembly block to the inside, so as to achieve the purpose of minimizing the pressure difference between the two ends and the middle. 3. The graphite column adopts a split combination setting, and the arc setting of the upper and lower ends of the graphite column can effectively transfer the pressure from the two ends to the center of the column core. At the same time, the connection between the middle column and the upper column and the lower column adopts a conical groove structure, so that the pressure can be evenly and effectively transferred to the center, further reducing the pressure difference, which can greatly improve the output and quality of industrial diamond products; 4. The coordination of the conductive cylinder, the conductive sheet, the alumina thermal insulation layer and the graphite column structure improves the thermal insulation effect while reducing the temperature difference. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0017] Figure 1 It is a schematic structural diagram of a diamond synthetic assembly block in an embodiment of the present invention.

[0018] In the figure: 1. conductive steel ring; 2. pyrophyllite ring; 3. alumina ring; 4. lower cylinder; 5. iron cup; 6. conductive sheet; 7. insulating bowl; 8. conductive cylinder; 9. alumina insulation layer; 10. pyrophyllite block; 11. upper cylinder; 12. middle cylinder. DETAILED DESCRIPTION

[0019] The present invention is described clearly below in conjunction with the drawings and specific embodiments in the embodiments of the present invention. The description herein is only used to explain the present invention, but is not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention.

[0020] Example

[0021] like Figure 1As shown, the present invention provides a graphite column for diamond synthesis, the graphite column includes an upper column 11, a middle column 12 and a lower column 4 which are connected in sequence, the outer side of the top of the upper column 11 is an arc convex upward, the central angle corresponding to the arc at the top of the upper column 11 is 15 degrees, a groove 2 is provided at the bottom of the upper column 11, the groove 2 is a conical groove narrow at the top and wide at the bottom, the central axis of the groove 2 coincides with the central axis of the upper column, the upper column 11 and the lower column 4 are symmetrical up and down, the top of the middle column 12 cooperates with the bottom of the upper column 11, and the bottom of the middle column 12 cooperates with the top of the lower column 4. The arc-shaped settings at the upper and lower ends of the graphite column can effectively transfer the pressure from both ends to the center of the column core. At the same time, the connection between the middle column 12 and the upper column 11 and the lower column 4 adopts a conical groove to interlock (that is, the connection is in the shape of a straw hat). The side wall of the groove 2 is inclined, and a lateral component of force can be generated when subjected to force, so that the pressure can be evenly and effectively transferred to the center, which can greatly improve product output and quality.

[0022] The method for making the graphite column at least comprises the following steps:

[0023] Step 1: mixing graphite powder and catalyst powder, wherein the catalyst powder is iron-nickel alloy catalyst powder;

[0024] Step 2: forming, pressing the mixed materials in step 1 into upper cylinder, middle cylinder and lower cylinder in corresponding molds;

[0025] Step 3: sintering: placing the upper cylinder, middle cylinder and lower cylinder pressed in step 2 into a sintering furnace for sintering;

[0026] Step 4: assemble, stack the sintered lower cylinder, middle cylinder and upper cylinder together in sequence.

[0027] The present embodiment also includes a diamond synthesis assembly block, including a phyllite block and a graphite column, the graphite column is the above-mentioned graphite column for diamond synthesis, the center of the phyllite block 10 is provided with a vertical cylindrical barrel-shaped through hole, the side wall of the barrel-shaped through hole is provided with an alumina insulation layer 9, a conductive cylinder 8 is sleeved in the barrel-shaped through hole, the upper and lower ends of the conductive cylinder 8 are provided with conductive sheets 6, the conductive sheets 6 are provided with an alumina ring 3, the alumina ring 3 is matched with a phyllite ring 2, the phyllite ring 2 is provided with a circle of grooves 1 on the surface corresponding to the alumina ring 3, the alumina ring 3 is provided with a circle of protrusions matched with the grooves 1, and the phyllite ring 2 is matched with a conductive steel ring 1; the pyrophyllite ring 2 and the alumina ring 3 matched with the conductive steel ring 1 have one protrusion and one concave, and the combined parts are perfectly matched, so that the pressure can be effectively transmitted from the upper and lower ends of the assembly block to the inside, so as to achieve the purpose of minimizing the pressure difference between the two ends and the middle. The alumina ring 3 and the alumina insulation layer 9 are made of sintered alumina powder. The high-temperature sintered alumina powder is used as the insulation layer to improve the insulation effect. The sintered alumina has less volatile impurities, which further improves the quality of the diamond. The alumina ring 3 and the alumina insulation layer 9 use alumina that has been treated at a high temperature of 1650°C, does not contain impurities and gas, has a high density, good pressure transmission, good insulation effect, reduces axial and radial temperature differences, and effectively improves product quality. The phyllite ring and the alumina ring at both ends of the composite block are connected by a snap-on buckle, which can transmit the pressure from the top hammer without loss, making the entire pressure field of the composite block more uniform.

[0028] A graphite column is arranged inside the conductive cylinder 8 , and an iron cup 5 and an insulating bowl 7 are arranged outside the graphite column in sequence.

[0029] The pyrophyllite block 10, the iron cup 5 and the insulating bowl 7 are all composed of two parts which are separated and symmetrical from top to bottom.

[0030] During operation, the pyrophyllite block, alumina thermal insulation layer, iron cup, insulating bowl and conductive cylinder are first assembled at the bottom, and then the lower cylinder, middle cylinder and upper cylinder of the graphite column wrapped in the insulating bowl and the iron cup are sequentially placed into the conductive cylinder, and finally the upper iron cup, insulating bowl, alumina thermal insulation layer and pyrophyllite block are buckled to form a complete diamond synthesis assembly block, and the next step of diamond synthesis operation can be carried out. The industrial diamond synthesized by the invention has good yield and high quality.

[0031] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A graphite column for diamond synthesis, Features: The graphite column includes three parts: an upper column, a middle column and a lower column connected in sequence. The outer side of the top of the upper column is an upward convex arc. The bottom of the upper column is provided with a second groove, and the second groove is a conical groove that is narrow at the top and wide at the bottom. The upper column and the lower column are symmetrical up and down, the top of the middle column cooperates with the bottom of the upper column, and the bottom of the middle column cooperates with the top of the lower column.

2. The graphite column for diamond synthesis according to claim 1, Features: The central angle of the arc on the outer side of the top of the upper cylinder is 15 degrees.

3. A method for making a graphite column as claimed in any one of claims 1 to 2, Features: At least the following steps are included: Step 1: mixing graphite powder and catalyst powder; Step 2: pressing, pressing the mixed materials in step 1 into upper cylinder, middle cylinder and lower cylinder in corresponding molds; Step 3: sintering: placing the upper cylinder, middle cylinder and lower cylinder pressed in step 2 into a sintering furnace for sintering; Step 4: assemble, stack the sintered lower cylinder, middle cylinder and upper cylinder together in sequence.

4. The method for making a graphite column according to claim 3, Features: The catalyst powder is iron-nickel alloy catalyst powder.

5. A diamond synthetic assembly block, comprising a pyrophyllite block and a graphite column, wherein the graphite column is as described in claim 1 or 2, Features: A vertical cylindrical through hole is provided at the center of the pyrophyllite block, an alumina insulation layer is provided on the side wall of the cylindrical through hole, a conductive cylinder is sleeved in the cylindrical through hole, conductive sheets are provided at both the upper and lower ends of the conductive cylinder, an alumina ring is provided on the conductive sheet, a pyrophyllite ring is matched on the alumina ring, a circle of grooves 1 is provided on the surface of the pyrophyllite ring corresponding to the alumina ring, a circle of protrusions matching the grooves 1 is provided on the alumina ring, and a conductive steel ring is matched on the pyrophyllite ring; The graphite column is arranged in the conductive cylinder, and an iron cup and an insulating bowl are arranged in sequence outside the graphite column in the conductive cylinder.

6. A diamond synthetic assembly block according to claim 5, Features: The pyrophyllite block, the alumina thermal insulation layer, the iron cup and the insulating bowl are all composed of two parts which are separated and symmetrical from top to bottom.

Images