Synthetic method of octahedral diamond

Abstract

The invention discloses an octahedral diamond synthesis method which comprises the following steps: preparing raw materials: selecting high-purity graphite powder and a powder catalyst, adding AlCl3 and KBH4 into the graphite powder to obtain graphite mixed powder, mixing the graphite mixed powder and the powder catalyst according to a weight ratio of (2-5): (5-8) to obtain mixed powder, adding a dispersing agent into the mixed powder, and uniformly mixing to obtain the raw materials, wherein the ratio of the dispersing agent to the mixed powder is 0.5: 6; the raw materials are put into a granulator to be granulated, and raw stone particles within 100 meshes are obtained; adding the raw stone particles into a mold, and pressing by adopting a four-column press to obtain a graphite core column; according to the method, in the diamond synthesis stage, the method of pressure subsection slow rising and power subsection slow rising is adopted, a good environment is provided for production of the octahedral diamond, the quality of the octahedral diamond is improved, the crystal form consistency is high, meanwhile, a high-position repeated mode is adopted in the pressure stage, and the performance of the diamond is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of diamond, and more specifically, to a method for synthesizing octahedral diamond. Background Art

[0002] Diamond is a superhard material with very high hardness. Most of the diamonds used in industry now are artificial. Artificial diamond not only has high hardness and good wear resistance, and can be widely used in cutting, grinding, and drilling; due to its high thermal conductivity and good electrical insulation, it can be used as a heat sink for semiconductor devices; it has excellent light transmittance and corrosion resistance, and is also widely used in the electronics industry. There are many types of diamonds, and octahedral diamond is one of them. It has good crystal form consistency and high crystal plane strength, can significantly improve the performance of related products, and is suitable for applications in the fields of high-precision and high-efficiency dressing and grinding.

[0003] The existing technology for artificially synthesizing octahedral diamond has defects. When synthesizing octahedral diamond, it mainly uses the method of quickly rising to high pressure in a short time. In this process, it is easy to cause low yield and low crystal flatness, increasing production costs. Therefore, we propose a method for synthesizing octahedral diamond. Summary of the Invention

[0004] The purpose of the present invention is to solve the defects existing in the prior art, and to propose a method for synthesizing octahedral diamond.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for synthesizing octahedral diamond, including the following steps: S1. Prepare raw materials: Select high-purity graphite powder and powder catalyst. Add AlCl3 and KBH4 to the graphite powder to obtain a graphite mixed powder. Mix the graphite mixed powder and the powder catalyst in a weight ratio of 2-5:5-8 to obtain a mixed powder. Add a dispersant to the mixed powder and mix evenly to obtain the raw materials, where the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulate: Put the raw materials into a granulator for granulation to obtain raw stone particles within 100 mesh; S3. Prepare the core column: Add the raw stone particles to a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5-4.5 mm; S4. Sinter the core column: Place the graphite core column in a vacuum environment, vacuum-treat it at 1100°C-1200°C for 14-15 hours, remove the dispersion solvent and oxygen impurities by a reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum-pack the graphite core column after it is taken out of the furnace; S5, Sintering: Place the graphite core column into the diamond synthesis block, and then put the diamond synthesis block into a cubic press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of gradually increasing the pressure in segments and gradually increasing the power in segments.

[0006] Preferably, the pressure in step S5 is set as follows: The cubic press is pressurized from 0 to 55 - 60 MPa at a speed greater than 2 MPa and then heating starts. Stop pressurizing and maintain for 400 - 450 s; then pressurize the pressure to 70 - 75 MPa within 20 s, stop pressurizing, and maintain for 20 - 60 s; then increase the pressure to 80 - 90 MPa within 70 s, stop pressurizing, and maintain for 60 - 90 s and then release the pressure. After releasing the pressure to 60 - 65 MPa, immediately pressurize to 80 - 90 MPa, and cycle three times like this, and finally release the pressure.

[0007] Preferably, the power in step S5 is set as follows: The starting power is 4000 - 5000 W, and this power is maintained for 250 s - 300 s. After that, increase the power to 6000 W - 6500 W within 30 s, maintain for 60 s - 80 s, then increase the power to 7000 - 7500 W within 60 s, maintain for 60 s - 80 s, and slowly increase by 1% every 30 seconds on this power basis. After increasing to 8500 - 9000 W, stop first, and then cool down naturally.

[0008] Preferably, the powder catalyst is composed of the following raw materials in parts by weight: Fe: 15 - 25 parts, Ni: 10 - 25 parts, Co: 8 - 16 parts, V: 0.02 - 2 parts, Ca: 0.05 - 0.2 parts, Mn: 3 - 4 parts.

[0009] Preferably, the dispersant is composed of 3 - 7 parts of sodium pyrophosphate, 2 - 6 parts of alkyl aryl phosphate, 4 - 8 parts of dialkyl sulfosuccinate, and 1 - 5 parts of reducing agent.

[0010] Preferably, the particle sizes of both the graphite powder and the powder catalyst are 150 mesh.

[0011] The technical effects and advantages of the present invention: 1. In the diamond synthesis stage of the present invention, by using the methods of gradually increasing the pressure in segments and gradually increasing the power in segments, a good synthesis environment is provided for the production of octahedral diamonds, improving the quality of the synthesized octahedral diamonds, with high crystal form consistency and high integrity. At the same time, in the pressure stage, the method of repeating at a high level is also adopted, which can effectively improve the impact resistance of diamonds.

[0012] 2. By adding AlCl3 and KBH4 to the graphite powder in the present invention, the combination of AlCl3 and KBH4 can improve the reduction effect during the subsequent synthesis of octahedral diamonds, reduce the generation of other metals during the reaction process, improve the synthesis effect, and reduce costs. Detailed implementation manners

[0013] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0014] Embodiment 1 Octahedral diamond synthesis method S1. Prepare raw materials: Select by weight: Fe: 15 parts, Ni: 10 parts, Co: 8 parts, V: 0.02 part, Ca: 0.05 part, Mn: 3 parts, put them into a mixer and mix evenly to obtain a powder catalyst, and the particle size of the powder catalyst is 150 mesh; (2) Select high-purity graphite powder with a particle size of 150 mesh, and add AlCl3 and KBH4 to the graphite powder to obtain a graphite mixed powder; (3) Select 3 parts of sodium pyrophosphate, 2 parts of alkyl aryl phosphate, 4 parts of dialkyl sulfosuccinate and 1 part of reducing agent, mix the sodium pyrophosphate, alkyl aryl phosphate and dialkyl sulfosuccinate evenly, and add them in 3 to 5 times during the mixing process, with an interval of 5 to 10 minutes each time, and finally obtain a dispersant.

[0015] (4) Mix the graphite mixed powder and the powder catalyst in a weight ratio of 2:5 to obtain a mixed powder, add a dispersant to the mixed powder and mix evenly to obtain raw materials, wherein the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulation: Put the raw materials into a granulator for granulation to obtain raw stone particles within 100 mesh; S3. Prepare a core column: Add the raw stone particles into a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5 to 4.5 mm; S4. Sinter the core column: Place the graphite core column in a vacuum environment, vacuum process it at 1100°C to 1200°C for 14 to 15 hours, remove the dispersing solvent and oxygen impurities by a reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum package the graphite core column after it is taken out of the furnace; S5. Sintering: Put the graphite core column into a diamond synthesis block, and then put the diamond synthesis block into a six-sided top press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of stepwise slow increase of pressure and stepwise slow increase of power respectively.

[0016] Among them, the pressure is set as follows: The cubic press is pressurized from 0 to 55 - 60 MPa at a speed greater than 2 MPa and then heating starts. The pressurization is stopped and maintained for 400 - 450 s; then the pressure is pressurized to 70 - 75 MPa within 20 s, the pressurization is stopped and maintained for 20 - 60 s; then the pressure is increased to 80 - 90 MPa within 70 s, the pressurization is stopped and maintained for 60 - 90 s and then the pressure is released. After the pressure is released to 60 - 65 MPa, it is immediately pressurized to 80 - 90 MPa, and this cycle is repeated three times, and finally the pressure is released; The power is set as follows: The starting power is 4000 - 5000 W, and this power is maintained for 250 s - 300 s. After that, the power is increased to 6000 W - 6500 W within 30 s and maintained for 60 s - 80 s. Then the power is increased to 7000 - 7500 W within 60 s and maintained for 60 s - 80 s. On this basis of power, it is slowly increased by 1% every 30 seconds. After increasing to 8500 - 9000 W, it stops first, and then cools down naturally.

[0017] Example 2 Octahedral diamond synthesis method S1. Prepare raw materials: (1). Select by weight: Fe: 20 parts, Ni: 17 parts, Co: 12 parts, V: 1.5 parts, Ca: 0.1 part, Mn: 3.5 parts. Put them into a mixer and mix evenly to obtain a powder catalyst, and the particle size of the powder catalyst is 150 mesh; (2). Select high-purity graphite powder with a particle size of 150 mesh, and add AlCl3 and KBH4 to the graphite powder to obtain a graphite mixed powder; (3). Select 5 parts of sodium pyrophosphate, 4 parts of alkylaryl phosphate, 6 parts of dialkyl sulfosuccinate and 2 parts of reducing agent. Mix the sodium pyrophosphate, alkylaryl phosphate and dialkyl sulfosuccinate evenly, and add them in 3 - 5 times during the mixing process, with an interval of 5 - 10 minutes each time, and finally obtain a dispersant.

[0018] (4). Mix the graphite mixed powder and the powder catalyst in a weight ratio of 3:6 to obtain a mixed powder. Add a dispersant to the mixed powder and mix evenly to obtain the raw materials, where the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulation: Put the raw materials into a granulator for granulation to obtain raw stone particles within 100 mesh; S3. Prepare the core column: Add the raw stone particles into a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5 - 4.5 mm; S4. Sintered core column: Place the graphite core column in a vacuum environment, vacuum-treat it at 1100°C - 1200°C for 14 - 15 hours, remove the dispersing solvent and oxygen impurities by reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum-pack the graphite core column after taking it out of the furnace; S5. Sintering: Place the graphite core column into the diamond synthesis block, and then put the diamond synthesis block into a six-sided top press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of stepwise slow increase of pressure and stepwise slow increase of power respectively.

[0019] Among them, the pressure is set as follows: Pressurize the six-sided top press from 0 to 55 - 60 MPa at a speed greater than 2 MPa to start heating, stop pressurizing, and maintain for 400 - 450 S; then pressurize the pressure to 70 - 75 MPa within 20 S, stop pressurizing, and maintain for 20 - 60 S; then increase the pressure to 80 - 90 MPa within 70 S, stop pressurizing, maintain for 60 - 90 S and then relieve the pressure, immediately pressurize to 80 - 90 MPa after relieving the pressure to 60 - 65 MPa, and cycle three times like this, and finally relieve the pressure; The power is set as follows: The starting power is 4000 - 5000 W, and this power is maintained for 250 S - 300 S. After the end, increase the power to 6000 W - 6500 W within 30 S and maintain for 60 S - 80 S, then increase the power to 7000 - 7500 W within 60 S and maintain for 60 S - 80 S, slowly increase by 1% within every 30 seconds on the basis of this power, stop after increasing to 8500 - 9000 W, and then cool down naturally.

[0020] Example 3 Octahedral diamond synthesis method S1. Preparation of raw materials: (1). Select by weight: Fe: 22 parts, Ni: 21 parts, Co: 13 parts, V: 1.6 parts, Ca: 0.13 parts, Mn: 4 parts, put them into a mixer and mix evenly to obtain a powder catalyst, and the particle size of the powder catalyst is 150 mesh; (2). Select high-purity graphite powder with a particle size of 150 mesh, and add AlCl3 and KBH4 to the graphite powder to obtain a graphite mixed powder; (3). Select 6 parts of sodium pyrophosphate, 5 parts of alkylaryl phosphate, 7 parts of dialkyl sulfosuccinate and 4 parts of reducing agent, mix the sodium pyrophosphate, alkylaryl phosphate and dialkyl sulfosuccinate evenly, and add them in 3 - 5 times during the mixing process, with an interval of 5 - 10 minutes each time, and finally obtain a dispersant.

[0021] (4)Mix the graphite mixed powder and the powder catalyst in a weight ratio of 4:7 to obtain a mixed powder. Add a dispersant to the mixed powder and mix evenly to obtain the raw material, where the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulation: Put the raw material into a granulator for granulation to obtain raw stone particles within 100 mesh; S3. Prepare the core column: Add the raw stone particles into a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5 - 4.5 mm; S4. Sinter the core column: Place the graphite core column in a vacuum environment, vacuum-treat it at 1100°C - 1200°C for 14 - 15 hours, remove the dispersing solvent and oxygen impurities by reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum-pack the graphite core column after it comes out of the furnace; S5. Sintering: Put the graphite core column into a diamond synthesis block, and then put the diamond synthesis block into a six-sided press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of stepwise slow increase of pressure and stepwise slow increase of power respectively.

[0022] Among them, the pressure is set as follows: Pressurize the six-sided press from 0 to 55 - 60 MPa at a speed greater than 2 MPa and start heating, then stop pressurizing and keep it for 400 - 450 S; then pressurize the pressure to 70 - 75 MPa within 20 S, stop pressurizing and keep it for 20 - 60 S; then increase the pressure to 80 - 90 MPa within 70 S, stop pressurizing and keep it for 60 - 90 S, then release the pressure, and immediately pressurize to 80 - 90 MPa after releasing the pressure to 60 - 65 MPa, and repeat this cycle three times, and finally release the pressure; The power is set as follows: The starting power is 4000 - 5000 W, and this power is maintained for 250 S - 300 S. After that, increase the power to 6000 W - 6500 W within 30 S and keep it for 60 S - 80 S, then increase the power to 7000 - 7500 W within 60 S and keep it for 60 S - 80 S. On this power basis, slowly increase it by 1% within every 30 seconds, stop after increasing to 8500 - 9000 W, and then cool down naturally.

[0023] Example 4 Octahedral diamond synthesis method S1. Prepare the raw material: (1)Select by weight: 25 parts of Fe, 25 parts of Ni, 16 parts of Co, 2 parts of V, 0.2 parts of Ca, 4 parts of Mn, put them into a mixer and mix evenly to obtain a powder catalyst, and the particle size of the powder catalyst is 150 mesh; (2)Select high-purity graphite powder with a particle size of 150 mesh, and add AlCl3 and KBH4 to the graphite powder to obtain a graphite mixed powder; (3) Select 7 parts of sodium pyrophosphate, 6 parts of alkyl aryl phosphate, 8 parts of dialkyl sulfosuccinate and 5 parts of reducing agent. Mix the sodium pyrophosphate, alkyl aryl phosphate and dialkyl sulfosuccinate evenly, and add them in 3 to 5 times during the mixing process, with an interval of 5 to 10 minutes each time, and finally obtain a dispersant.

[0024] (4) Mix the graphite mixed powder and the powder catalyst in a weight ratio of 5:8 to obtain a mixed powder. Add a dispersant to the mixed powder and mix evenly to obtain a raw material, where the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulation: Put the raw material into a granulator for granulation to obtain raw stone particles within 100 meshes; S3. Prepare the core column: Add the raw stone particles into a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5 - 4.5 mm; S4. Sinter the core column: Place the graphite core column in a vacuum environment, vacuum process it at 1100°C - 1200°C for 14 - 15 hours, remove the dispersing solvent and oxygen impurities by reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum package the graphite core column after taking it out of the furnace; S5. Sintering: Put the graphite core column into a diamond synthesis block, and then put the diamond synthesis block into a six-sided press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of pressure segmented slow rise and power segmented slow rise respectively.

[0025] Among them, the pressure is set as follows: Pressurize the six-sided press from 0 to 55 - 60 MPa at a speed greater than 2 MPa and start heating, stop pressurizing, and maintain for 400 - 450 S; then pressurize the pressure to 70 - 75 MPa within 20 S, stop pressurizing, and maintain for 20 - 60 S; then raise the pressure to 80 - 90 MPa within 70 S, stop pressurizing, maintain for 60 - 90 S and then relieve the pressure. After relieving the pressure to 60 - 65 MPa, immediately pressurize to 80 - 90 MPa, and cycle three times in this way, and finally relieve the pressure; The power is set as follows: The starting power is 4000 - 5000 W, and this power is maintained for 250 S - 300 S. After that, raise the power to 6000 W - 6500 W within 30 S and maintain for 60 S - 80 S, then raise the power to 7000 - 7500 W within 60 S and maintain for 60 S - 80 S. On the basis of this power, slowly raise it by 1% every 30 seconds. After raising it to 8500 - 9000 W, stop first, and then cool down naturally.

[0026] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for synthesizing octahedral diamond, characterized in that, It includes the following steps: S1. Prepare raw materials: Select high-purity graphite powder and powder catalyst. Add AlCl3 and KBH4 to the graphite powder to obtain graphite mixed powder. Mix the graphite mixed powder and the powder catalyst in a weight ratio of 2-5:5-8 to obtain a mixed powder. Add a dispersant to the mixed powder and mix evenly to obtain the raw materials, where the ratio of the dispersant to the mixed powder is 0.5:6; S2. Granulate: Put the raw materials into a granulator for granulation to obtain raw stone particles within 100 mesh; S3. Prepare the core column: Add the raw stone particles into a mold and press them with a four-column press to obtain a graphite core column with a thickness of 2.5-4.5 mm; S4. Sinter the core column: Place the graphite core column in a vacuum environment, perform vacuum treatment at 1100°C-1200°C for 14-15 hours, remove the dispersing solvent and oxygen impurities by reduction method, then cool it to room temperature under a protective gas, store it in a vacuum environment, and vacuum package the graphite core column after taking it out of the furnace; S5. Sintering: Put the graphite core column into a diamond synthesis block, and then put the diamond synthesis block into a six-sided press for synthesis. The actual synthesis pressure and temperature are synthesized by using the methods of pressure sectional slow rise and power sectional slow rise respectively.

2. The method for synthesizing octahedral diamond according to claim 1, wherein: The pressure in step S5 is set as follows: Pressurize the six-sided press from 0 to 55-60 MPa at a speed greater than 2 MPa to start heating, stop pressurizing, and maintain for 400-450 S; then pressurize the pressure to 70-75 MPa within 20 S, stop pressurizing, and maintain for 20-60 S; then raise the pressure to 80-90 MPa within 70 S, stop pressurizing, maintain for 60-90 S and then relieve the pressure. After relieving the pressure to 60-65 MPa, immediately pressurize to 80-90 MPa, and repeat this cycle three times, and finally relieve the pressure.

3. The method for synthesizing octahedral diamond according to claim 1, characterized in that: The power in step S5 is set as follows: The starting power is 4000-5000 W, and this power is maintained for 250 S-300 S. After that, the power is adjusted to 6000 W-6500 W within 30 S and maintained for 60 S-80 S. Then the power is adjusted to 7000-7500 W within 60 S and maintained for 60 S-80 S. On this power basis, it is slowly adjusted by 1% every 30 seconds. After adjusting to 8500-9000 W, stop first, and then cool down naturally.

4. A method for synthesizing octahedral diamond according to claim 1, characterized in that: The powder catalyst is composed of the following raw materials in parts by weight: Fe: 15-25 parts, Ni: 10-25 parts, Co: 8-16 parts, V: 0.02-2 parts, Ca: 0.05-0.2 parts, Mn: 3-4 parts.

5. A method for synthesizing octahedral diamond according to claim 1, characterized in that: The dispersant is composed of 3-7 parts of sodium pyrophosphate, 2-6 parts of alkyl aryl phosphate, 4-8 parts of dialkyl sulfosuccinate and 1-5 parts of reducing agent.

6. The method for synthesizing octahedral diamond according to claim 1, characterized in that: The particle sizes of both the graphite powder and the powder catalyst are 150 mesh.