A method for producing a diamond having a surface with etch pits

Abstract

The present application belongs to the technical field of synthetic diamond production, and proposes a method for synthesizing diamond with etch pits on the surface. A 300-mesh fine powder catalyst and spherical graphite are prepared, and the raw materials are premixed and granulated. The granulated mixture is loaded into a mold, and a four-column press is used to press a core column. The core column is placed in a vacuum furnace for vacuum hot reduction treatment, and after cooling, it is taken out of the furnace and vacuum packaged. The core column is subjected to high-temperature and high-pressure synthesis using a six-sides press. The synthesized graphite rod is broken, soaked in mixed acid, and then placed in aqua regia for heating. The water is boiled and dried. By controlling the ratio of catalyst additives and matching a specific process, the present application can effectively etch the surface of the diamond, achieving the purpose of synthesizing diamond with etch pits on the surface. The product can achieve good bonding ability with the bonding agent, allowing the diamond cutter to exhibit good grinding performance and extending the actual service life. This is conducive to reducing production costs and is suitable for large-scale promotion.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of synthetic diamond production, and particularly relates to a synthetic method of diamond with etch pits on the surface. BACKGROUND

[0002] Diamond has excellent mechanical, electrical, thermal and chemical properties, and is widely used in petroleum drilling, stone processing, mechanical processing, electronic industry, aerospace, biosensor, semiconductor and quantum device fields, and is particularly introduced into the grinding industry as super abrasive to significantly improve the processing efficiency and processing quality of parts, and also prolongs the life of the grinding wheel and improves the dimensional stability of the processed parts. In actual grinding process, because the diamond surface is relatively smooth and not rough enough, the bonding between the diamond and the binder is not firm, and in the grinding process, the phenomenon of whole diamond particle falling off often occurs, which greatly shortens the service life.

[0003] At present, in order to meet the requirement of diamond surface with etch pits, surface coating or surface etching technology is mainly used to change the properties of diamond surface, such as the method for improving diamond growth quality by metal or metal oxide assisted etching disclosed in patent CN202311185878.2, and the method for etching the surface of artificial diamond disclosed in CN202110800050.8. Through such methods, the diamond surface is roughened, which can solve the problem of low holding force to a certain extent from the physical aspect, but the cost is relatively high and the technical difficulty is relatively large, and there are still some deficiencies in actual long-term production. SUMMARY

[0004] In view of the above technical problems of diamond, the present application provides a synthetic method of diamond with etch pits on the surface by adding catalyst, matching specific process, and realizing the effect of etching the surface of diamond, so as to improve the grinding performance and service life of diamond tool.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: the present application provides a synthetic method of diamond with etch pits on the surface, which comprises the following steps:

[0006] S1, prepare 300-mesh fine powder catalyst for standby, the raw material of the powder catalyst includes Ni 19%, Pr 0.2%, FeS 0.8%, and Fe 80% by weight percentage;

[0007] S2, select 300-mesh fine spherical graphite, the purity of the graphite reaches 30 PPM or less of impurity content;

[0008] S3, FeS and trace rare earth elements are added to the powder catalyst for premixing for 3h±15min, and then the premixed catalyst is mixed with graphite in a mass ratio of 10:3~10:6 in a three-dimensional mixer for 3~5h, and then is put into a granulator for twice granulation for standby;

[0009] S4, the granulated mixture is loaded into a mold, and a four-column press is used to press into a core column;

[0010] S5, the core column pressed in step S4 is placed in a vacuum furnace, the temperature in the vacuum furnace is 1080±5 degrees, vacuum treatment is performed for 8~10h, impurities are removed by hydrogen reduction, and then the core column is naturally cooled to room temperature under nitrogen protection, and after being taken out of the furnace, it is vacuum packaged;

[0011] S6, the core column taken out of the furnace is loaded into a synthetic block, and is baked and heated, and a six-surface press is used to synthesize it at high temperature and high pressure, the synthesis temperature in the synthesis process is 1380 degrees~1460 degrees, the heating time is 2600±110 seconds, and the internal pressure of the synthesis cavity is 5.2~5.3Gpa;

[0012] S7, the synthesized graphite rod is broken, the graphite rod is soaked in mixed acid for 1~2h after being broken, the graphite is removed, and then the catalyst is removed by placing the graphite rod in a beaker and heating for 20min;

[0013] S8, the product treated in S7 is boiled, and after being fried dry, a diamond with etch pit-shaped crystal surface is obtained.

[0014] In step S6, the pressure of the six-surface press is adjusted in real time:

[0015] a1, the pressure of the six-surface press is uniformly over-pressured to 42Mpa at a speed of 0.6Mpa / s of the hydraulic system, and then heating is started;

[0016] a2, then increase to 49Mpa at a speed of 0.35Mpa / s, and keep pressure for 580s~620s;

[0017] a3, increase the pressure to 58Mpa within 15s, and keep pressure for 120s;

[0018] a4, slowly over-press to 61Mpa within 360s, and keep pressure for 280s;

[0019] a5, slowly over-press to 65Mpa within 380s, and keep pressure for 280s;

[0020] a6, quickly over-press to 70Mpa within 30s, and keep pressure for 300s;

[0021] a7, again quickly over-press to 78Mpa within 20s, enter the pressure keeping stage, keep pressure for 180s~210s, and then take out with heat;

[0022] a8, pressure relief to 72 MPa at 0.2 MPa / s, pressure maintaining for 20 s;

[0023] a9, pressure relief to 30 MPa at 0.55 MPa / s, and heat stopping;

[0024] a10, fast pressure relief is completed.

[0025] The power of the cubic press is adjusted in real time in step S6:

[0026] b1, the initial power of the cubic press is 9.6 kw~9.8 kw, and the initial power is maintained for 620 s~660 s;

[0027] b2, the power is first lowered, and the power is lowered to 8.2 kw~8.4 kw within 20 s, and maintained for 150 s~180 s;

[0028] b3, the power is then raised to 8.3 kw within 30 s, and maintained for 200 s;

[0029] b4, the power is then raised to 8.4 kw, and maintained for 480 s;

[0030] b5, the power is then lowered to 8.35 kw, and then uniformly lowered to 8.15 kw, and then raised to 8.25 kw within 250 s, at this time, the final pressure maintaining stage is reached, the cooling is started in advance, and the pressure relief and cooling are simultaneously performed;

[0031] b6, the pressure relief to 30 MPa is completed, and the heat stopping is finished.

[0032] Preferably, the size of the core column in step S4 is 57 mm X 49 mm, and the density of the core column is 3.2~3.4 g / cm3.

[0033] Compared with the prior art, the application has the advantages and positive effects that:

[0034] 1. The diamond synthesis method with etch pits on the surface provided by the application can effectively achieve the purpose of synthesizing diamond with etch pits on the surface by controlling the proportion of catalyst additives and matching specific processes, including mixing time, vacuum treatment and high temperature and high pressure process. The synthesized product using the process of the application can obtain good bonding capacity with the bonding agent, enabling the diamond tool to exhibit good grinding performance during actual grinding operation, and the actual service life is also extended, which is beneficial to reduce production cost and is suitable for large-scale promotion. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiment description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.

[0036] Figure 1 A process curve diagram of a diamond synthesis method with etched pits on the surface provided for the embodiment;

[0037] Figure 2 A process diagram of synthesizing diamond with etched pits on the surface of the present application;

[0038] Figure 3 A process diagram of synthesizing diamond with etched pits on the surface of the present application;

[0039] Figure 4 A process diagram of synthesizing diamond with etched pits on the surface of the present application;

[0040] Figure 5 A product diagram of synthesizing diamond with etched pits on the surface of the present application. DETAILED DESCRIPTION

[0041] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can be practiced in different ways from those described herein, therefore, the present application is not limited to the specific embodiments disclosed in the following description.

[0042] Embodiments, as shown in the present application, provide a diamond synthesis method with etched pits on the surface, comprising the following steps: Figures 1-5

[0043] S1, prepare 300 mesh fine powder catalyst for standby, the raw material of the powder catalyst includes Ni 19%, Pr 0.2%, FeS 0.8%, Fe 80% by weight percentage;

[0044] S2, select 300 mesh fine spherical graphite, the purity of graphite reaches 30 PPM below the impurity content;

[0045] S3, add FeS and trace rare earth elements to the powder catalyst for pre-mixing 3h±15min, then mix the pre-mixed catalyst with graphite in a three-dimensional mixer at a mass ratio of 10:3~10:6 for 3~5h, and then put it into a granulator for twice granulation standby;

[0046] S4, put the granulated mixture into the mold, and press it into a core column with a four-column press;

[0047] ​S5, the core column pressed in step S4 is placed into a vacuum furnace, the temperature in the vacuum furnace is 1080±5 degrees, vacuum treatment is carried out for 8-10 hours, impurities are removed by hydrogen reduction, and then natural cooling is carried out under nitrogen protection until room temperature, and after furnace discharge, vacuum packaging is carried out;

[0048] S6, the core column after furnace discharge is loaded into a synthetic block, baking heating is carried out, and a six-surface pressing machine is used for high-temperature and high-pressure synthesis, the synthesis temperature in the synthesis process is 1380-1460 degrees, the heating time is 2600±110 seconds, and the internal pressure of the synthesis cavity is 5.2-5.3 Gpa;

[0049] S7, the synthesized graphite rod is broken, the graphite rod after breaking is soaked in mixed acid for 1-2 hours, the graphite is removed, and then the catalyst is removed by placing in a beaker and heating for 20 minutes;

[0050] S8, the product treated in S7 is boiled, and after frying, the diamond with etch pit-shaped crystal surface is obtained.

[0051] In order to improve the production quality and production efficiency of synthetic diamond, the pressure and power of the six-surface pressing machine are dynamically adjusted in real time in step S6, and the adjustment steps of the pressure of the six-surface pressing machine during work include:

[0052] a1, the pressure of the six-surface pressing machine is uniformly supercharged to 42 Mpa at a speed of 0.6 Mpa / s of the hydraulic system, and then heating is started;

[0053] a2, then supercharged to 49 Mpa at a speed of 0.35 Mpa / s, and pressure maintaining is carried out for 580-620 seconds;

[0054] a3, the pressure is increased to 58 Mpa within 15 seconds, and pressure maintaining is carried out for 120 seconds;

[0055] a4, slowly supercharged to 61 Mpa within 360 seconds, and pressure maintaining is carried out for 280 seconds;

[0056] a5, slowly supercharged to 65 Mpa within 380 seconds, and pressure maintaining is carried out for 280 seconds;

[0057] a6, rapidly supercharged to 70 Mpa within 30 seconds, and pressure maintaining is carried out for 300 seconds;

[0058] a7, again rapidly supercharged to 78 Mpa within 20 seconds, enters the pressure maintaining stage, and after pressure maintaining for 180-210 seconds, hot pressure relief is carried out;

[0059] a8, pressure relief is carried out to 72 Mpa at a speed of 0.2 Mpa / s, and pressure maintaining is carried out for 20 seconds;

[0060] a9, pressure relief is carried out to 30 Mpa at a speed of 0.55 Mpa / s, and hot stopping is carried out;

[0061] a10, fast pressure relief is completed.

[0062] In step S6, the power of the cubic press is adjusted in real time in coordination with the pressure adjustment step of the cubic press as follows:

[0063] b1, the initial power of the cubic press is 9.6kw~9.8kw, and the initial power is maintained for 620s~660s;

[0064] b2, the power is first lowered, and the power is lowered to 8.2kw~8.4kw within 20s and maintained for 150s~180s;

[0065] b3, the power is then raised to 8.3kw within 30s and maintained for 200s;

[0066] b4, the power is then raised to 8.4kw and maintained for 480s;

[0067] b5, the power is then lowered to 8.35kw, then uniformly lowered to 8.15kw, and then raised to 8.25kw within 250s, at which time the final pressure maintaining phase is reached, the cooling is started in advance, and the pressure relief and cooling are performed simultaneously;

[0068] b6, the pressure relief is stopped at 30Mpa to end the cooling.

[0069] By controlling the ratio of catalyst additives and matching specific processes, including premixing, secondary mixing, mixing time, vacuum furnace station performing vacuum treatment, and cubic press station performing high temperature and high pressure process, especially the pressure and power adjustment steps of the process, the purpose of synthesizing diamond with etch pits on the surface can be effectively achieved. The synthesized product using the process can obtain good bonding capacity with the bonding agent, so that the diamond tool exhibits good grinding performance during actual grinding operation, and the actual service life is also prolonged. Furthermore, the present application can effectively reduce production costs, is suitable for planned mass production in the workshop, and is suitable for large-scale promotion.

[0070] In order to improve the matching of the core column and the cubic press, the cubic press used in the present application has a ¢850 cylinder diameter, a 70X70mm hammer face, a 42 degree hammer face angle, HT-V electric control, and the core column produced in step S4 has a size of ¢57mmX49mm and a density of 3.2~3.4g / cm3, which is beneficial to the cubic press to exert external force on the synthesized block and the core column and to provide a high temperature and high pressure environment, and is beneficial to controlling the synthesis efficiency of synthetic diamond.

[0071] In order to ensure the performance of the strong acid in step S7, the mixed acid used in the present application is sulfuric acid:nitric acid=3:1, and the aqua regia is hydrochloric acid:nitric acid=3:1.

[0072] The above merely describes preferred embodiments of the present application, but is not intended to limit the present application to other forms, any person skilled in the art can make changes or modifications to the above disclosed technical contents into equivalent embodiments with equivalent changes, and apply to other fields, but any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solution content of the present application still belongs to the protection scope of the present application technical solution.

Claims

1. A method for synthesizing a surface-etched diamond, characterized by, The method comprises the following steps: S1, preparing a 300-mesh fine powder catalyst, the raw material of the powder catalyst comprises, by weight percentage, Ni 19%, Pr 0.2%, FeS 0.8%, and Fe 80%; S2, selecting 300-mesh fine spherical graphite, the purity of the graphite reaches 30 PPM or less; S3, adding FeS and trace rare earth elements to the powder catalyst for premixing for 3 h ± 15 min, then mixing the premixed catalyst with the graphite in a mass ratio of 10:3-10:6 in a three-dimensional mixer for 3-5 h, and then putting the mixture into a granulator for twice granulation for standby; S4, loading the granulated mixture into a mold, and pressing the mixture into a core column by using a four-column press; S5, putting the core column pressed in step S4 into a vacuum furnace, setting the temperature in the vacuum furnace to 1080 ± 5 degrees, vacuum treating for 8-10 h, reducing and removing impurities by using hydrogen, and then naturally cooling to room temperature under nitrogen protection, and vacuum packaging after being taken out of the furnace; S6, loading the core column taken out of the furnace into a synthetic block, baking and heating the core column, and synthesizing the core column by using a six-surface press, the synthesis temperature in the synthesis process is 1380-1460 degrees, the heating time is 2600 ± 110 seconds, and the internal pressure of the synthesis cavity is 5.2-5.3 Gpa; S7, crushing the synthesized graphite rod, immersing the crushed graphite rod in mixed acid for 1-2 h to remove the graphite, and then putting the graphite rod in a beaker containing aqua regia and heating for 20 min to remove the catalyst; S8, boiling water and frying the product treated in step S7 to obtain diamond with etch pit-shaped crystal faces.

2. The method of claim 1, wherein the surface of the diamond is etched. The pressure of the six-surface press in step S6 is adjusted in real time as follows: a1, uniformly increasing the pressure of the six-surface press to 42 Mpa at a speed of 0.6 Mpa / s by using a hydraulic system, and then starting heating; a2, increasing the pressure to 49 Mpa at a speed of 0.35 Mpa / s, and keeping the pressure for 580-620 s; a3, increasing the pressure to 58 Mpa within 15 s, and keeping the pressure for 120 s; a4, slowly increasing the pressure to 61 Mpa within 360 s, and keeping the pressure for 280 s; a5, slowly increasing the pressure to 65 Mpa within 380 s, and keeping the pressure for 280 s; a6, rapidly increasing the pressure to 70 Mpa within 30 s, and keeping the pressure for 300 s; a7, rapidly increasing the pressure to 78 Mpa within 20 s again, entering a pressure keeping stage, keeping the pressure for 180-210 s, and then unloading the pressure with heat; a8, unloading the pressure to 72 Mpa at a speed of 0.2 Mpa / s, and keeping the pressure for 20 s; a9, unloading the pressure to 30 Mpa at a speed of 0.55 Mpa / s, and stopping the heating; a10, rapidly unloading the pressure.

3. The method of claim 2, wherein the surface of the diamond is etched with a plurality of pits. The power of the six-surface press in step S6 is adjusted in real time as follows: b1, the starting power of the six-surface press is 9.6-9.8 kw, and the starting power is kept for 620-660 s; b2, the power is reduced to 8.2-8.4 kw within 20 s for the first time, and the power is kept for 150-180 s; b3, the power is increased to 8.3 kw within 30 s, and the power is kept for 200 s; b4, the power is increased to 8.4 kw, and the power is kept for 480 s; b5, the power is reduced to 8.35kw, then uniformly reduced to 8.15kw, then increased to 8.25kw within 250s, at this time, it is in the final pressure maintaining stage, the temperature is reduced in advance, and the temperature is reduced while the pressure is released; b6, the pressure is released to 30Mpa to stop heat and end.

4. The method of claim 3, wherein the surface of the diamond is etched to have a plurality of pits. The core column size in the step S4 is 57mmX49mm, and the core column density is 3.2~3.4g / cm3.

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