A high-performance polycrystalline diamond compact and its preparation method

Abstract

The present invention relates to the technical field of superhard materials, and particularly to a high-performance polycrystalline diamond compact and a preparation method thereof. The high-performance polycrystalline diamond compact comprises a polycrystalline diamond layer and a cemented carbide substrate located on one side of the polycrystalline diamond layer; the polycrystalline diamond layer contains 5-25 wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns. By additionally adding coarse-grained diamond particles, the PDC compact of the present invention can effectively improve the impact resistance of the polycrystalline layer of the PDC compact while maintaining high wear resistance. Additionally, by adding 5-25 wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns to the diamond raw material, the present invention can block the continuous growth of cracks, thereby improving the impact resistance of the polycrystalline diamond layer and enabling the polycrystalline diamond compact to have both wear resistance and impact resistance at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of superhard materials, and particularly to a high-performance polycrystalline diamond compact and a preparation method thereof. Background Art

[0002] A polycrystalline diamond compact is a superhard composite material made from diamond micropowder and a cemented carbide substrate by firing under high temperature and high pressure conditions. The polycrystalline diamond compact combines the wear resistance of diamond and the impact resistance of cemented carbide, and is therefore widely used in fields such as oil drilling, geological drilling, and coalfield mining.

[0003] Currently, there are many methods to improve the overall impact resistance of polycrystalline diamond compacts, but little mention is made of how to improve the impact resistance of the diamond layer. Compared with the cemented carbide substrate, the diamond layer has high hardness and good wear resistance, but its impact toughness is far from satisfactory. This causes the diamond layer of the compact to be easily damaged under high impact during use, rendering the entire compact ineffective. When the compact is impacted during actual use, cracks will originate from the gaps between diamond grains with lower strength, and as the impact process continues, the cracks will continuously grow along the grain boundaries between diamonds until the entire diamond layer ruptures.

[0004] In the prior art, the impact resistance and wear resistance of polycrystalline diamond compacts are usually adjusted by regulating the particle size of diamond grains. Coarser diamond grains can provide better impact resistance, while finer diamond grains can provide higher wear resistance. However, in actual applications, it is usually required that the polycrystalline diamond compact simultaneously has good impact resistance and good wear resistance, which is obviously difficult to achieve simply by adjusting the particle size.

[0005] Therefore, the prior art still needs to be improved and developed. Summary of the Invention

[0006] In view of the deficiencies of the above prior art, the purpose of the present invention is to provide a high-performance polycrystalline diamond compact and a preparation method thereof, aiming to solve the problem that the diamond layer of the existing polycrystalline diamond compact cannot simultaneously possess good wear resistance and impact resistance.

[0007] The technical solution of the present invention is as follows:

[0008] A high-performance polycrystalline diamond compact includes a polycrystalline diamond layer and a cemented carbide substrate located on one side of the polycrystalline diamond layer; the polycrystalline diamond layer contains 5-25 wt% of coarse diamond grains with a D50 particle size of 25-45 microns.

[0009] A preparation method of a high-performance polycrystalline diamond compact includes the steps:

[0010] Mix diamond micropowders with different particle sizes below 15 microns to obtain diamond raw materials;

[0011] Add coarse-grained diamond particles to the diamond micropowders and mix them to obtain a premix; the D50 particle size of the coarse-grained diamond particles is 25 - 45 microns;

[0012] Load the premix into a mold, and then place a cemented carbide matrix to obtain an assembly;

[0013] Place the assembly in a top press for sintering treatment to obtain the high-performance polycrystalline diamond composite sheet.

[0014] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the diamond raw materials are selected from two or more of the diamond micropowders with particle sizes below 15 microns for mixing.

[0015] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the mass of the coarse-grained diamond particles accounts for 5% - 25% of the total mass of the diamond raw materials.

[0016] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the mass of the coarse-grained diamond particles accounts for 10% - 15% of the total mass of the diamond raw materials.

[0017] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the D50 particle size of the coarse-grained diamond particles is 1.5 - 5 times the D50 particle size of the main-grained diamond in the diamond raw materials.

[0018] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the mold is a metal cup.

[0019] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the material of the metal cup is one of zirconium, niobium, molybdenum, and tantalum.

[0020] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the top press is a six-sided top press.

[0021] The method for preparing the high-performance polycrystalline diamond composite sheet, wherein the pressure of the sintering treatment is 5.5 - 10.0 GPa, the temperature of the sintering treatment is 1300 - 1800 °C, and the time of the sintering treatment is 200 - 600 s.

[0022] Beneficial effects: The present invention provides a high-performance polycrystalline diamond compact and a preparation method thereof. The high-performance polycrystalline diamond compact includes a polycrystalline diamond layer and a cemented carbide substrate located on one side of the polycrystalline diamond layer. The polycrystalline diamond layer contains 5-25 wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns. By additionally adding coarse-grained diamond particles, the PDC compact of the present invention can effectively improve the impact resistance of the polycrystalline layer of the PDC compact while maintaining high wear resistance. When traditional diamond compacts are subjected to continuous impact, fine cracks will occur in the gaps between diamond particles with relatively weak strength in the polycrystalline layer. As the impact continues, the microcracks will continuously grow along the diamond gaps until the entire polycrystalline diamond layer is damaged and the compact fails. However, the present invention additionally adds 5-25 wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns to the diamond raw material, which can block the continuous growth of cracks, thereby improving the impact resistance of the polycrystalline diamond layer and enabling the polycrystalline diamond compact to have both wear resistance and impact resistance at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural diagram of a high-performance polycrystalline diamond compact of the present invention;

[0024] Figure 2 is a schematic structural diagram of the process of coarse-grained diamond particles in the diamond layer of the high-performance polycrystalline diamond compact of the present invention blocking crack growth. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention provides a high-performance polycrystalline diamond compact and a preparation method thereof. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. 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.

[0026] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those of ordinary skill in the art to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted in an idealized or overly formal sense unless specifically defined as here.

[0027] As Figure 1 shown, the present invention provides a high-performance polycrystalline diamond compact, including a polycrystalline diamond layer 1 and a cemented carbide substrate 2 located on one side of the polycrystalline diamond layer. The polycrystalline diamond layer 1 contains 5-25 wt% of coarse-grained diamond particles 3 with a D50 particle size of 25-45 microns.

[0028] When the composite piece is under continuous impact during actual use, microcracks are likely to occur in the gaps between diamond particles with relatively weak strength. As the impact continues, the microcracks will continuously grow along the gaps between diamond particles until the entire polycrystalline diamond layer ruptures. However, in the present invention, by additionally adding 5-25 wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns to the polycrystalline diamond layer of the composite piece, it can play a role in blocking the growth of cracks; as Figure 2 shown, when the microcrack 4 encounters coarse-grained diamond particles with relatively high strength during the growth process along the gaps between diamond particles, the growth process of the microcrack 4 will be blocked.

[0029] In this embodiment, the coarse-grained diamond particles with a D50 particle size of 25-45 microns refer to: among the coarse-grained diamond particles, the particle size corresponding to when the cumulative particle size distribution percentage reaches 50% is 25-45 microns.

[0030] In addition, the present invention provides a method for preparing a high-performance polycrystalline diamond composite piece, including the steps:

[0031] Step S10: Mix diamond micropowders with different particle sizes below 15 microns to obtain a diamond raw material;

[0032] Step S20: Add coarse-grained diamond particles to the diamond micropowders and mix them to obtain a premix; the D50 particle size of the coarse-grained diamond particles is 25-45 microns;

[0033] Step S30: Load the premix into a mold, and then place a cemented carbide substrate to obtain an assembled part;

[0034] Step S40: Place the assembled part in a top press for sintering treatment to obtain the high-performance polycrystalline diamond composite piece.

[0035] In the present invention, by additionally adding coarse-grained diamond particles with a D50 particle size of 25-45 microns to the polycrystalline diamond layer of the composite piece, it can play a role in blocking the growth of cracks; combined with loading the premix into a mold and then placing a cemented carbide substrate to obtain an assembled part in the preparation method; and then placing the assembled part in a top press for sintering treatment, it can effectively improve the wear resistance and impact resistance of the polycrystalline diamond composite piece; when the crack encounters coarse-grained diamond particles with relatively high strength during the growth process along the gaps between diamond particles, the crack growth process will be blocked.

[0036] In some embodiments, the diamond raw material is selected from two or more of diamond micropowders with a particle size below 15 microns for mixing.

[0037] For example, the particle size of the diamond micropowder includes but is not limited to 1 μm, 2 μm, 3 μm, 4 μm, 4.5 μm, 5 μm, 6 μm, 8 μm, 9.5 μm. Of course, it is not limited to integers and can be natural numbers from 0 to 15. In this embodiment, diamond micropowders with two or more particle sizes are mixed as the diamond raw material. Mixing diamond micropowders with two or more different particle sizes as the diamond raw material can make the prepared polycrystalline diamond composite sheet have high wear resistance.

[0038] In some embodiments, the mass of the coarse-grained diamond particles accounts for 5%-25% of the total mass of the diamond raw material. When the addition amount of the coarse-grained diamond particles in the polycrystalline diamond layer of the composite sheet is less than 5wt%, the improvement effect on the impact resistance of the diamond layer is not obvious; when the addition amount of the coarse-grained diamond particles in the polycrystalline diamond layer of the composite sheet is higher than 25wt%, the wear resistance of the original composite sheet will be reduced. Therefore, in order to ensure that the impact resistance of the polycrystalline diamond layer is improved without reducing the wear resistance of the original composite sheet, the mass of the coarse-grained diamond particles needs to account for 5%-25% of the total mass of the diamond raw material. Only in this way can it have both high wear resistance and high impact resistance.

[0039] In a preferred embodiment, the mass of the coarse-grained diamond particles accounts for 10%-15% of the total mass of the diamond raw material; at this proportion of the mass of the coarse-grained diamond particles, the best wear resistance and impact resistance effects can be achieved, and the service life of the polycrystalline diamond composite sheet can be extended.

[0040] In some embodiments, the D50 particle size of the coarse-grained diamond particles is 1.5-5 times the D50 particle size of the main-grained diamond in the diamond raw material. When the D50 particle size of the coarse-grained diamond particles is less than 1.5 times the D50 particle size of the diamond raw material, the improvement effect on the impact resistance of the diamond layer is not obvious; when the D50 particle size of the coarse-grained diamond particles is greater than 5 times the D50 particle size of the diamond raw material, the wear resistance of the original composite sheet will be reduced; therefore, in order to ensure that the impact resistance of the polycrystalline diamond layer is improved without reducing the wear resistance of the original composite sheet, the D50 of 5-25wt% of the coarse-grained diamond particles is determined to be 25-45 μm, and the D50 particle size of the coarse-grained diamond particles is 1.5-5 times the D50 particle size of the main-grained diamond in the diamond raw material.

[0041] In some embodiments, the mold is a metal cup.

[0042] In some embodiments, the material of the metal cup is one of zirconium, niobium, molybdenum, and tantalum; selecting a metal cup of these materials is not easily cracked or damaged under high temperature and high pressure.

[0043] In some embodiments, the top press is a six-sided top press.

[0044] In some embodiments, the pressure of the sintering treatment is 5.5 - 10.0 GPa, the temperature of the sintering treatment is 1300 - 1800 °C, and the time of the sintering treatment is 200 - 600 s. Such sintering treatment pressure, temperature, and time can further enhance the wear resistance and impact resistance of the polycrystalline diamond composite sheet and extend the service life of the polycrystalline diamond composite sheet.

[0045] The following further gives examples to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention.

[0046] Comparative Example 1

[0047] A method for preparing a high-performance polycrystalline diamond composite sheet includes the following steps:

[0048] Two or more kinds of diamond micropowders with a particle size below 15 microns are mixed evenly according to a certain mass ratio to obtain a diamond raw material; among them, the mass ratio of diamond particles with a particle size of 12 - 15 microns is 40%, the mass ratio of diamond particles with a particle size of 8 - 10 microns is 30%, and the mass ratio of diamond particles with a particle size of 5 - 8 microns is 30%.

[0049] The evenly mixed diamond micropowders are loaded into a metal cup, and then a cemented carbide substrate is placed to obtain an assembled part; among them, the material of the metal cup is niobium metal;

[0050] The assembled part is placed in a six-sided top press for high-temperature and high-pressure sintering to obtain a diamond composite sheet; among them, the high-temperature and high-pressure sintering conditions are: pressure 6.0 GPa, temperature 1400 °C, and sintering time 600 S.

[0051] The wear ratio of the diamond composite sheet prepared through the above process is: 2083×10 4 , and the average impact energy is: 240 J, as shown in Table 1 specifically.

[0052] Example 1

[0053] A method for preparing a high-performance polycrystalline diamond composite sheet includes the following steps:

[0054] After mixing two or more diamond micropowders with a particle size below 15 microns in a certain mass ratio and making them evenly mixed, diamond raw materials are obtained; among them, the mass ratio of diamond particles with a particle size of 12 - 15 microns is 40%, the mass ratio of diamond particles with a particle size of 8 - 10 microns is 30%, and the mass ratio of diamond particles with a particle size of 5 - 8 microns is 30%.

[0055] In the evenly mixed diamond raw materials, 5% - 25% of coarse - grained diamond particles with a D50 of 25 - 45 microns are additionally added based on the total mass of the diamond raw materials, and then mixed evenly again; among them, the D50 of the coarse - grained diamond particles is 30 microns, and the proportion is 10% of the total mass of the diamond raw materials.

[0056] The evenly mixed diamond micropowders are loaded into a metal cup, and then a cemented carbide matrix is placed in it to obtain an assembled part; among them, the material of the metal cup is niobium metal;

[0057] The assembled part is placed in a cubic press for high - temperature and high - pressure sintering to obtain a diamond composite sheet; among them, the high - temperature and high - pressure sintering conditions are: pressure 6.0 Gpa, temperature 1400 °C, and sintering time 600 S.

[0058] For the diamond composite sheet prepared through the above process, its wear ratio is: 2142×10 4 , and the average impact energy is: 320 J, and the impact resistance performance is improved by about 33% compared with the original diamond composite sheet, as shown in Table 1 specifically.

[0059] Comparative Example 2

[0060] A preparation method of a high - performance polycrystalline diamond composite sheet includes the following steps:

[0061] After mixing two or more diamond micropowders with a particle size below 15 microns in a certain mass ratio and making them evenly mixed, diamond raw materials are obtained; among them, the mass ratio of diamond particles with a particle size of 10 - 12 microns is 70%, and the mass ratio of diamond particles with a particle size of 5 - 8 microns is 30%.

[0062] The evenly mixed diamond raw materials are loaded into a metal cup, and then a cemented carbide matrix is placed in it to obtain an assembled part; among them, the material of the metal cup is zirconium metal;

[0063] The assembled part is placed in a cubic press for high - temperature and high - pressure sintering to obtain a diamond composite sheet; among them, the high - temperature and high - pressure sintering conditions are: pressure 7.0 Gpa, temperature 1500 °C, and sintering time 400 S.

[0064] For the diamond composite sheet prepared through the above process, its wear ratio is: 3984×10 4 , and the average impact energy is: 260 J, as shown in Table 1 specifically.

[0065] Example 2

[0066] A preparation method of a high-performance polycrystalline diamond composite sheet, comprising the following steps:

[0067] After mixing two or more diamond micropowders with a particle size of less than 15 microns in a certain mass ratio, diamond raw materials are obtained; among them, the mass ratio of diamond particles with a particle size of 10-12 microns is 70%, and the mass ratio of diamond particles with a particle size of 5-8 microns is 30%.

[0068] In the uniformly mixed diamond raw materials, additionally add coarse-grained diamond particles with a D50 of 25-45 microns accounting for 5%-25% of the total mass of the diamond raw materials, and then mix evenly again; among them, the D50 of the coarse-grained diamond particles is 25 microns, and the proportion is 15% of the total mass of the diamond raw materials.

[0069] Put the diamond micropowders that are evenly mixed again into a metal cup, and then put a cemented carbide substrate to obtain an assembled part; among them, the material of the metal cup is zirconium metal;

[0070] Put the assembled assembled part into a cubic press for high-temperature and high-pressure sintering to obtain a diamond composite sheet; among them, the high-temperature and high-pressure sintering conditions are: pressure 7.0 Gpa, temperature 1500 °C, sintering time 400 S.

[0071] The abrasion ratio of the diamond composite sheet prepared through the above process is: 4032×10 4 , the average impact energy is: 350 J, and the impact resistance performance is improved by about 35% compared with the original diamond composite sheet, as specifically shown in

[0072] Table 1.

[0073]

[0074] In summary, the present invention provides a high-performance polycrystalline diamond composite sheet and a preparation method thereof, wherein the high-performance polycrystalline diamond composite sheet comprises a polycrystalline diamond layer and a cemented carbide substrate located on one side of the polycrystalline diamond layer; the polycrystalline diamond layer contains 5-25wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns. The present invention can effectively improve the impact resistance of the polycrystalline layer of the PDC composite sheet while maintaining high wear resistance by adding coarse-grained diamond particles. When a conventional diamond composite sheet is subjected to continuous impact, fine cracks will be generated in the gaps between diamond particles with weaker strength in the polycrystalline layer. As the impact continues, the microcracks continue to grow along the diamond gaps until the entire polycrystalline diamond layer is damaged and the composite sheet fails. The present invention further adds 5-25wt% of coarse-grained diamond particles with a D50 particle size of 25-45 microns to the diamond raw material, which can prevent the continued growth of cracks, thereby improving the impact resistance of the polycrystalline diamond layer, so that the polycrystalline diamond composite sheet has both wear resistance and impact resistance. Therefore, the polycrystalline diamond composite sheet prepared by the present invention solves the problem that it is difficult for existing diamond composite sheets to have both wear resistance and impact resistance.

[0075] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A method for preparing a high-performance polycrystalline diamond compact, characterized in that, it includes the steps of: mixing two or more kinds of diamond micropowders with a particle size below 15 microns to obtain a diamond raw material; adding coarse-grained diamond particles to the diamond micropowders and mixing them to obtain a premix; the D50 particle size of the coarse-grained diamond particles is 25 - 45 microns; loading the premix into a mold and then placing a cemented carbide substrate to obtain an assembly; putting the assembly into a top press for sintering treatment to obtain the high-performance polycrystalline diamond compact; the mass of the coarse-grained diamond particles accounts for 5% - 25% of the total mass of the diamond raw material; the D50 particle size of the coarse-grained diamond particles is 1.5 - 5 times the D50 particle size of the main-grained diamond in the diamond raw material; the pressure of the sintering treatment is 5.5 - 10.0 GPa, the temperature of the sintering treatment is 1300 - 1800 °C, and the time of the sintering treatment is 200 - 600 s.

2. The method for preparing a high-performance polycrystalline diamond compact according to claim 1, characterized in that, the mass of the coarse-grained diamond particles accounts for 10% - 15% of the total mass of the diamond raw material.

3. The method for preparing a high-performance polycrystalline diamond compact according to claim 1, characterized in that, the mold is a metal cup.

4. The method for preparing a high-performance polycrystalline diamond compact according to claim 3, characterized in that, the material of the metal cup is one of zirconium, niobium, molybdenum, and tantalum.

5. The method for preparing a high-performance polycrystalline diamond compact according to claim 1, characterized in that, the top press is a six-sided top press.

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