阅读说明：本技术 爆炸冲击合成多晶金刚石微粉生产工艺 (Production process for synthesizing polycrystalline diamond micropowder by explosive impact ) 是由 曾元金 于 2020-12-01 设计创作，主要内容包括：本发明公开了爆炸冲击合成多晶金刚石微粉生产工艺,采用液压机将多段样品管中的混合物挤出,工作效率较高；且避免采用车床、钻床可能造成的工具损坏,避免增加生产成本；采用将制得的多晶金刚石放入烧结炉中,全程充氮气保护,进行多段独特的温度加温保温处理,将金刚石的强度韧性提高,采用本申请制得的金刚石进行工件生产,能提升加工工件20％的强度韧性；采取冰冻干燥机去除金刚石水份后,多晶金刚石微粉相当疏松,多晶金刚石微粉之间形成了多孔疏松状,当要再次分散时,易于分散,免除了烘干后的研磨粉碎工序。(The invention discloses a production process for synthesizing polycrystalline diamond micropowder by explosive impact, which adopts a hydraulic press to extrude a mixture in a plurality of sections of sample tubes, and has higher working efficiency; the tool damage possibly caused by adopting a lathe and a drilling machine is avoided, and the increase of the production cost is avoided; the prepared polycrystalline diamond is placed in a sintering furnace, nitrogen is filled in the whole process for protection, and multi-section unique temperature heating and heat preservation treatment is carried out, so that the strength and toughness of the diamond are improved, and the strength and toughness of a processed workpiece can be improved by 20 percent when the diamond prepared by the method is used for workpiece production; after the moisture of the diamond is removed by adopting a freeze dryer, the polycrystalline diamond micro powder is quite loose, a porous loose state is formed among the polycrystalline diamond micro powder, and when the polycrystalline diamond micro powder needs to be dispersed again, the polycrystalline diamond micro powder is easy to disperse, so that the grinding and crushing process after drying is omitted.)

1. The production process for synthesizing polycrystalline diamond micropowder by explosive impact is characterized by comprising the following steps:

s1, mixing graphite, metal additives and metal powder by a mixer;

s2, punching the uniformly mixed graphite, metal additives and metal powder into a mixed block by a punch;

s3, sintering the punched mixed block, punching the mixed block again to form a mixed block, and repeating sintering and punching until the mixed block reaches the required density;

s4, placing the mixed block with qualified density into a sample tube of an explosive synthesis diamond device;

s5, exploding the diamond explosion synthesizing device to generate a mixture of graphite, diamond, metal additives and metal powder;

s6, shearing the sample tube into multiple sections by a shearing machine;

s7, extruding the mixture in the multi-section sample tube by adopting a hydraulic press;

s8, putting the extruded mixture into a material burning pot, and putting the material burning pot into a high-temperature furnace with protective atmosphere to heat the material to 1100 ℃ so as to separate the graphite and the diamond from the metal additives and the metal powder;

s9, separating the graphite and the diamond to obtain pure diamond;

s10, placing the obtained diamond into a sintering furnace, filling nitrogen for the whole process for protection, raising the temperature of a heating curve in the sintering furnace from room temperature to 300 ℃ after 140 minutes, and preserving the heat for 1 hour; raising the temperature to 400 ℃ after 50 minutes, and preserving the heat for 1 hour; heating to 500 deg.C for 50 min, and maintaining for 1 hr; raising the temperature to 550 ℃ after 50 minutes, and preserving the heat for 2 hours; naturally cooling to below 100 deg.C, opening the furnace door, and taking out the diamond.

2. The process for producing a polycrystalline diamond micropowder by explosive impact synthesis according to claim 1, further comprising step S11: and putting the diamond into a ball milling tank to be milled to a proper size.

3. The process for producing a polycrystalline diamond micropowder by explosive impact synthesis according to claim 2, further comprising step S12: and (4) removing water from the diamond subjected to ball milling treatment by using a freeze dryer.

Technical Field

The invention belongs to the technical field of diamond production equipment, and particularly relates to a production process for synthesizing polycrystalline diamond micropowder by explosive impact.

Background

Diamond is an ideal material for grinding and polishing due to the characteristic of 'hardest world', and because natural polycrystalline diamond (Carbonado type) has rare yield and high price, the diamond is generally manufactured by people at present. At present, the methods for artificially manufacturing diamond only comprise three methods, namely a static pressure method, a detonation method and an explosion method. The diamonds produced by the static pressure method are all single crystals, the grain diameter is usually between 40 and 200 mu m, and the method is suitable for manufacturing common diamond grinding wheels, common polishing abrasive materials and the like; the diamond produced by the detonation method is also single crystal, the average grain diameter is very small, usually about 12nm, the commercial dry powder aggregate particle size reaches 2 mu m, even a suspension prepared by a modifier and a surfactant has the coarsest aggregate particle size of 130-150 nm, the aggregate particle size distribution in the suspension is wide, and the diamond is mainly used as a lubricant at present; the diamond produced by the explosion method is polycrystalline diamond which is closest to natural carbonado diamond, and is suitable for grinding and polishing chips and hard disks.

At present, the method for synthesizing diamond by explosion is to put graphite powder into a mould and press it into cylindrical (round, square or rectangular) graphite compact whose shape is consistent with that of the flying piece in the explosion device. In order to adjust the density of the graphite compact, some graphite powders are added with metal powders such as iron, copper, cobalt and the like; still others add a binder such as resin while adding metal powder, and remove the resin by low temperature (less than 300 ℃) sintering while improving the density of the graphite compact. Then, the graphite compact is placed under the flyer of the explosive device, and a certain distance is ensured (the distance is the height). Detonate the detonator above the explosion device to explode the explosive column, push the flying piece to strike the graphite compact at a certain flying speed, and generate high temperature and high pressure in the graphite powder to cause transient phase change of the graphite. And finally, recovering the scattered graphite ash, screening and washing the graphite ash, and carrying out metal removal and residual graphite removal treatment by using strong acid such as nitric acid, sulfuric acid and the like and chemical agents such as strong oxidants and the like to obtain the synthesized diamond.

In the prior art, in the process of producing polycrystalline diamond by using explosive impact, in order to completely recover materials after explosion and prevent the materials from flying and being difficult to recover, the synthesized materials are required to be sealed in a thick and strong container, and how to take the materials out of the container after diamond synthesis becomes a difficult problem.

And because the polycrystalline diamond is formed by converting graphite under the explosion impact, the conversion time is very short and is finished within microseconds, the polycrystalline diamond has defects and micro stress inside, and the strength and the toughness are not high.

Polycrystalline diamond micropowder, particularly 1.5 micron fine polycrystalline diamond, is easy to agglomerate and agglomerate under the conventional drying condition, is not easy to disperse in the use of customers, causes scratches on the surface of an object to be ground and polished, and affects the processing quality.

Therefore, there is a need to develop a process for producing polycrystalline diamond micropowder by explosive impact synthesis.

Disclosure of Invention

In order to solve the problems in the background technology, the invention provides a production process for synthesizing polycrystalline diamond micropowder by explosive impact.

In order to achieve the purpose, the invention provides the following technical scheme:

the production process of explosive impact synthesis of polycrystalline diamond micropowder includes the following steps:

s1, mixing graphite, metal additives and metal powder by a mixer;

s2, punching the uniformly mixed graphite, metal additives and metal powder into a mixed block by a punch;

s3, sintering the punched mixed block, punching the mixed block again to form a mixed block, and repeating sintering and punching until the mixed block reaches the required density;

s4, placing the mixed block with qualified density into a sample tube of an explosive synthesis diamond device;

s5, exploding the diamond explosion synthesizing device to generate a mixture of graphite, diamond, metal additives and metal powder;

s6, shearing the sample tube into multiple sections by a shearing machine;

s7, extruding the mixture in the multi-section sample tube by adopting a hydraulic press;

s8, putting the extruded mixture into a material burning pot, and putting the material burning pot into a high-temperature furnace with protective atmosphere to heat the material to 1100 ℃ so as to separate the graphite and the diamond from the metal additives and the metal powder;

s9, separating the graphite and the diamond to obtain pure diamond;

s10, placing the obtained diamond into a sintering furnace, filling nitrogen for the whole process for protection, raising the temperature of a heating curve in the sintering furnace from room temperature to 300 ℃ after 140 minutes, and preserving the heat for 1 hour; raising the temperature to 400 ℃ after 50 minutes, and preserving the heat for 1 hour; heating to 500 deg.C for 50 min, and maintaining for 1 hr; raising the temperature to 550 ℃ after 50 minutes, and preserving the heat for 2 hours; naturally cooling to below 100 deg.C, opening the furnace door, and taking out the diamond;

specifically, the method further includes step S11: and putting the diamond into a ball milling tank to be milled to a proper size.

Specifically, the method further includes step S12: and (4) removing water from the diamond subjected to ball milling treatment by using a freeze dryer.

Compared with the prior art, the invention has the beneficial effects that:

the invention adopts the hydraulic press to extrude the mixture in the multi-section sample tube, so the working efficiency is higher; the tool damage possibly caused by adopting a lathe and a drilling machine is avoided, and the increase of the production cost is avoided;

the prepared polycrystalline diamond is placed in a sintering furnace, nitrogen is filled in the whole process for protection, and multi-section unique temperature heating and heat preservation treatment is carried out, so that the strength and toughness of the diamond are improved, and the strength and toughness of a processed workpiece can be improved by 20% when the diamond prepared by the method is used for workpiece production;

according to the invention, after the moisture of the diamond is removed by adopting the freeze dryer, the polycrystalline diamond micro powder is quite loose, a porous loose state is formed among the polycrystalline diamond micro powder, and the polycrystalline diamond micro powder is easy to disperse when being dispersed again, so that the grinding and crushing process after drying is omitted.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention provides the following technical scheme:

the production process of explosive impact synthesis of polycrystalline diamond micropowder includes the following steps:

s1, mixing graphite, metal additives and metal powder by a mixer;

s2, punching the uniformly mixed graphite, metal additives and metal powder into a mixed block by a punch;

s3, sintering the punched mixed block, punching the mixed block again to form a mixed block, and repeating sintering and punching until the mixed block reaches the required density;

s4, placing the mixed block with qualified density into a sample tube of an explosive synthesis diamond device; the sample tube adopted here generally adopts a steel tube with the diameter of 120mm and the length of 1200 mm;

s5, exploding the diamond explosion synthesizing device to generate a mixture of graphite, diamond, metal additives and metal powder;

s6, shearing the sample tube into multiple sections by a shearing machine; the length of each section is 200 mm;

s7, extruding the mixture in the multi-section sample tube by adopting a 200-ton hydraulic press;

s8, putting the extruded mixture into a material burning pot, and putting the material burning pot into a high-temperature furnace with protective atmosphere to heat the material to 1100 ℃ so as to separate the graphite and the diamond from the metal additives and the metal powder;

s9, separating the graphite and the diamond to obtain pure diamond;

s10, placing the obtained diamond into a sintering furnace, filling nitrogen for the whole process for protection, raising the temperature of a heating curve in the sintering furnace from room temperature to 300 ℃ after 140 minutes, and preserving the heat for 1 hour; raising the temperature to 400 ℃ after 50 minutes, and preserving the heat for 1 hour; heating to 500 deg.C for 50 min, and maintaining for 1 hr; raising the temperature to 550 ℃ after 50 minutes, and preserving the heat for 2 hours; naturally cooling to below 100 deg.C, opening the furnace door, and taking out the diamond;

s11, putting the diamond into a ball milling tank and milling the diamond to a proper size;

and S12, removing water from the diamond subjected to ball milling treatment by using a freeze dryer.

By adopting the production process, polycrystalline diamond micro powder can be synthesized by impact, the efficiency is improved, the cost is reduced, and the industrial production is realized.

In addition, the band saw is not used for cutting the sample tube, because the band saw is easy to wear and break, the use cost is high, and the efficiency is low;

the hydraulic press adopted by the application extrudes the mixture in the multiple sections of sample tubes, so that the working efficiency is higher; and avoid adopting the instrument that lathe, drilling machine probably caused to damage, avoid increasing manufacturing cost.

According to the method, the copper blocks and the diamond powder are separated by melting at high temperature, so that the problem that a large amount of waste water, waste gas and the like possibly caused by an electrolytic method or a chemical solvent pollute the environment or the problems of long time, low efficiency and high cost are solved.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.