High-pressure manufacturing method of self-sharpening diamond, product and application

Abstract

The invention belongs to the technical field of diamond manufacturing, and particularly relates to a high-pressure manufacturing method of a self-sharpening diamond, a product and application, and the high-pressure manufacturing method of the self-sharpening diamond comprises the following steps: mixing graphite and an iron-nickel alloy, pressurizing to 6GPa or more, heating the pressurized graphite and iron-nickel alloy to 1400 DEG C or more, and cooling to room temperature to obtain the self-sharpening diamond. The self-sharpening diamond is obtained after the heating time of the graphite and the iron-nickel alloy is smaller than or equal to 4 minutes, the conversion rate of the graphite forming the self-sharpening diamond is larger than 50%, the self-sharpening diamond does not have an original growth face, and the self-sharpening diamond obtained through the high-pressure manufacturing method of the self-sharpening diamond can be smashed into the specific particle size to obtain self-sharpening diamond particles. The self-sharpening diamond particles can be used for producing polishing pads or fretsaws, the diameters of the self-sharpening diamond particles are smaller than 10 micrometers, the self-sharpening diamond particles can be used for polishing silicon or silicon carbide wafers, the self-sharpening diamond is high in growth speed, and the generation amount of the self-sharpening diamond can be increased.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond manufacturing, and in particular relates to a high-pressure manufacturing method, a product and a use of a self-sharpening diamond. Background Art

[0002] The high-pressure diamond abrasives currently produced focus on impact strength, which is usually expressed as a room temperature toughness index (Toughness Index or Tl); or a high temperature toughness index (Thermal Toughness Index or TTI). However, diamond abrasives with too high impact strength will greatly increase the cutting temperature of the abrasive surface due to friction with the workpiece when the diamond is blunted, causing damage to the workpiece surface. What's more, the abrasive may be broken or pulled out of the diamond binder and fall off, so the service life of the abrasive tool will be shortened. The present invention appropriately reduces TTI when manufacturing diamonds so that the abrasive can break by itself at the high temperature of blunting, thereby forming a new cutting point, avoiding the expansion of the grinding surface area of ​​the diamond abrasive, thereby extending the life of the abrasive tool and continuously cutting the workpiece.

[0003] The high temperature and high pressure production of diamond or diamond grit usually uses graphite as the raw material and iron, cobalt, nickel or their alloys as the catalyst. The pressure is maintained in the stable zone of diamond growth at the catalyst melting temperature. The liquefied catalyst will dissolve the graphite and deposit diamond.

[0004] The high-pressure equipment can be a six-sided top press. The reaction chamber pressure is generated by applying oil pressure to the piston to push the top hammer to apply pressure to the packaging module outside the central reaction chamber, thereby applying pressure roughly evenly to the mixed column of graphite and catalyst. Afterwards, electricity is applied to the mixed column or to the graphite tube outside the mixed column to increase the temperature, melt the catalyst, dissolve the graphite and deposit diamonds.

[0005] The longer the growth time of synthetic abrasive grains is, the larger the abrasive grains are. For example, the abrasive grains that grow for 50 minutes are about 35 mesh. In addition, the slower the growth rate, the more complete the crystal shape is, the higher the TI value is, and the fewer defects in the abrasive grains are, so the TTI value is close to the TI value. Such diamond abrasive grains with complete crystal shape and few defects are usually fixed with sintered metal binders and made into cutting and grinding discs. One of the cutting and grinding tools is a diamond saw blade, which is used to impact and cut hard and brittle workpieces, such as sawing granite. However, when used for sawing softer marble, the cutting point cannot be too blunt, and abrasive grains with irregular crystal shape are usually used. But even so, the sharp diamond will not break by itself due to insufficient internal defects, and the abrasive grains are easily blunted during sawing, which leads to increased sawing power and too hot temperature on the cutting surface, which will shorten the life of the tool. However, the existing self-sharpening diamond production method is imperfect and the output is low, so a self-sharpening diamond preparation method and its product that can extend the life of cutting or grinding tools are needed. Summary of the invention

[0006] In view of the above problems, the present invention proposes a high-pressure manufacturing method, product and use of self-sharpening diamond, which effectively solves the problems of short life of existing cutting and grinding tools, imperfect self-sharpening diamond production methods and low output.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] [1] A high-pressure method for producing self-sharpening diamonds, comprising: mixing graphite and an iron-nickel alloy and pressurizing them to 6 GPa or above, heating the pressurized graphite and the iron-nickel alloy to 1400° C. or above, obtaining self-sharpening diamonds after heating the graphite and the iron-nickel alloy for 4 minutes or less, and obtaining a self-sharpening diamond having a conversion rate of greater than 50% from the graphite to the self-sharpening diamonds, and having no original growth surface.

[0009] Furthermore, the self-sharpening diamond is grown under pressure by a six-sided top press.

[0010] Furthermore, the raw material for preparing the self-sharpening diamond includes graphite and the weight proportion of graphite is ≥40%.

[0011] Furthermore, the graphite is crystallized flake graphite powder.

[0012] Furthermore, the impact strength of the self-sharpening diamond is lower than that of crystalline diamond abrasive grains of the same size.

[0013] [2] A self-sharpening diamond produced by the high-pressure production method for self-sharpening diamond described in [1].

[0014] [3] A self-sharpening diamond particle obtained by crushing the self-sharpening diamond described in [2] into a specific particle size.

[0015] Furthermore, the self-sharpening diamond particles can be used to produce polishing pads or wire saws.

[0016] Further, the self-sharpening diamond particles have a diameter less than 10 microns;

[0017] Furthermore, the self-sharpening diamond particles can be used to polish silicon or silicon carbide wafers.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The self-sharpening diamond obtained by the high-pressure manufacturing method of the self-sharpening diamond of the present invention not only has a fast growth rate, but also can increase the amount of self-sharpening diamond generated. The self-sharpening diamond contains more micron-sized catalyst inclusions and graphite flakes. These self-sharpening diamonds can be crushed to make self-sharpening diamond particles.

[0020] The self-sharpening diamond particles obtained by the high-pressure manufacturing method of the self-sharpening diamond in the present invention can be used to make a polishing pad by manufacturing a resin binder, or can be fixed by electroplating nickel to prepare a cutting wire saw. Since the diamond particles contain a large amount of micron-sized catalysts, the high temperature generated when the abrasive particles are blunted will cause the diamond edges in contact with the catalyst to graphitize. At this time, the volume of the self-sharpening diamond will increase by two times, causing the self-sharpening diamond to crack at high temperatures, thereby generating new cutting points so that the abrasive particles continue to penetrate the workpiece, so that the power or energy for polishing or cutting the workpiece can be reduced, thereby extending the service life of the tool. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] A high-pressure manufacturing method for self-sharpening diamond, comprising:

[0023] Step 1: Evenly mix graphite and iron-nickel alloy powders in a weight ratio of 6:4;

[0024] Step 2: cold isostatically press the mixture of graphite and iron-nickel alloy in step 1 into a graphite catalyst column, and place the graphite catalyst column into a synthetic block encapsulating pyrophyllite;

[0025] Step 3: Place the synthetic block in step 2 into a six-sided top press, and then pressurize it to 6GPa. At this time, the graphite catalyst column is quickly heated to above 1400°C by electric current, and the displacement sensor of the top hammer is observed at the same time.

[0026] Step 4: After the graphite catalyst column in step 3 is melted, the top hammer is displaced and accelerated. After heating for 4 minutes, the six-sided top press is powered off and the pressure is reduced after the graphite catalyst column is solidified.

[0027] Step 5: Take out the reacted graphite catalyst column and crush it, then remove metal and other impurities from the reacted graphite catalyst column by acid washing, and then take it out and obtain self-sharpening diamond. At this time, the conversion rate of graphite to form self-sharpening diamond is greater than 50%, and the self-sharpening diamond obtained does not have the original growth surface.

[0028] In this embodiment, the graphite is crystallized flake graphite powder.

[0029] In this embodiment, the impact strength of the self-sharpening diamond is lower than that of crystalline diamond abrasive grains of the same size.

[0030] A self-sharpening diamond particle is obtained by crushing the self-sharpening diamond into a specific particle size. The method of crushing the self-sharpening diamond can adopt a crushing method such as a multi-knife crushing method, a ball mill crushing method, and an air flow crushing method.

[0031] In this embodiment, the self-sharpening diamond particles can be used to produce a polishing pad or a wire saw. The polishing pad or the wire saw can be obtained by fixing the polishing pad or the wire saw carrier by using a resin binder or electroplating nickel.

[0032] In this embodiment, the self-sharpening diamond particles are crushed by a multi-knife crushing method, a ball mill crushing method, an air flow crushing method, etc., and the diameter is less than 10 microns;

[0033] In this embodiment, the self-sharpening diamond particles with a diameter less than 10 microns are added with an equal proportion of polishing liquid, and the mixture of the self-sharpening diamond particles with a diameter less than 10 microns and the polishing liquid is added to a polishing device, and after the polishing device is started, it can be used to polish silicon or silicon carbide wafers.

[0034] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high pressure method for producing self-sharpening diamonds, characterized in that: The graphite and iron-nickel alloy are mixed and pressurized to 6 GPa or above, and the pressurized graphite and iron-nickel alloy are heated to 1400° C. or above. Self-sharpening diamonds are obtained after the heating time of the graphite and iron-nickel alloy is less than or equal to 4 minutes. The conversion rate of the graphite to form self-sharpening diamonds is greater than 50%, and the self-sharpening diamonds do not have an original growth surface.

2. The high pressure method for producing self-sharpening diamond according to claim 1, characterized in that: The self-sharpening diamond is grown by applying pressure through a six-sided top press.

3. The high pressure method for producing self-sharpening diamond according to claim 1, characterized in that: The raw material for preparing the self-sharpening diamond includes graphite, and the weight proportion of graphite is ≥40%.

4. The high pressure method for producing self-sharpening diamond according to claim 3, characterized in that: The graphite is crystallized flake graphite powder.

5. The high pressure method for producing self-sharpening diamond according to claim 1, characterized in that: The impact strength of the self-sharpening diamond is lower than that of crystalline diamond abrasive grains of the same size.

6. A self-sharpening diamond produced by the high-pressure production method for self-sharpening diamond according to any one of claims 1 to 5.

7. Self-sharpening diamond particles obtained by crushing the self-sharpening diamond according to claim 6 into a specific particle size.

8. The self-sharpening diamond particle according to claim 7, characterized in that: The self-sharpening diamond particles can be used to produce polishing pads or wire saws.

9. The self-sharpening diamond particle according to claim 7, characterized in that: The self-sharpening diamond particles have a diameter less than 10 microns.

10. The self-sharpening diamond particle according to claim 9, characterized in that: The self-sharpening diamond particles can be used to polish silicon or silicon carbide wafers.