A method for manufacturing a polycrystalline diamond compact

Abstract

This invention discloses a method for manufacturing polycrystalline diamond composite sheets. Diamond micropowder is mixed with a metal catalyst and sintered under high temperature and high pressure to form polycrystalline diamond. The polycrystalline diamond is then cut into polycrystalline particles with a particle size of 0.2-3 mm using laser or mechanical processing. The polycrystalline particles are then mixed with diamond micropowder and sintered with a cemented carbide matrix under high temperature and high pressure to form a polycrystalline diamond composite sheet. The beneficial effects of this invention include: the diamond composite sheet prepared according to this method significantly improves wear resistance and impact resistance, extends the service life of the polycrystalline diamond layer, and significantly enhances the connection stability between the diamond layer and the cemented carbide matrix.

Description

Technical Field

[0001] This invention relates to the field of diamond composite sheets, and more specifically to a method for manufacturing polycrystalline diamond composite sheets. Background Technology

[0002] Diamond composite sheets are widely used in machining, geological drilling, and the extraction of ores, oil, and natural gas. Due to the need to adapt to various working conditions, the impact resistance and wear resistance of diamond composite sheets are extremely high.

[0003] Existing polycrystalline diamond composite sheets are all composite materials formed by high-temperature and high-pressure sintering of a fine-grained diamond polycrystalline layer with a particle size of 0.5μm-60μm and a cemented carbide matrix. The fine-grained diamond polycrystalline layer increases wear resistance, while the cemented carbide matrix improves impact resistance. However, in actual drilling applications, although the upper diamond cutting edge has high wear resistance, the impact toughness of this fine-grained polycrystalline layer is still poor. During operation, the top fine-grained polycrystalline layer is prone to cracking or chipping away, leading to failure and reducing the product's service life.

[0004] Furthermore, the bonding surface between the fine-grained polycrystalline diamond layer and the cemented carbide matrix is ​​too smooth. During the sintering process, due to the inherent differences in the properties of these two materials, the adhesion between the polycrystalline diamond and the cemented carbide layer is reduced, the impact resistance of the polycrystalline diamond layer decreases, and it is easy to fall off during operation, causing drill bit failure. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a method for manufacturing polycrystalline diamond composite sheets, which increases the wear resistance and impact resistance of the polycrystalline diamond layer, as well as the bonding performance between the diamond layer and the cemented carbide layer.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for manufacturing a polycrystalline diamond composite sheet, characterized by comprising the following steps:

[0008] S1. Select diamond micro powder with a particle size of 1-70μm and mix it evenly with the metal catalyst in a container;

[0009] S2. The container is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6Gpa-8Gpa to sinter diamond polycrystalline material.

[0010] S3. Diamond polycrystalline materials are laser-processed or mechanically processed to obtain polycrystalline particles with a particle size of 0.2mm-3mm;

[0011] S4. Metal removal treatment: Place the polycrystalline particles into a sealed container containing acid solution, heat to 50-250℃, and react for 2-20 hours until the metal in the polycrystalline particles is completely dissolved to obtain polycrystalline diamond particles with a particle size of 0.2-3mm.

[0012] S5. First, mix polycrystalline diamond particles with a particle size of 0.2-3mm with diamond micro powder with a particle size of 1-70μm and place them in a high-temperature resistant metal container. Then, place the cemented carbide matrix on top of 1.5-3.5g of diamond powder and cover it with a metal lid.

[0013] S6. The container from step S5 is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6Gpa-10Gpa for sintering to obtain a polycrystalline diamond composite sheet.

[0014] Further, in step S1, the diamond micro powder and the metal catalyst are mixed at a weight ratio of 1:0.05 to 1:0.20.

[0015] Furthermore, the metal catalyst is one or more of Fe, Co, and Ni, and the metal catalyst exists in the form of elemental powder, alloy powder, alloy particles, or alloy flakes.

[0016] Furthermore, the acid solution in step S4 is aqua regia, hydrofluoric acid, or a mixture of the two, with a concentration of 50%-80%.

[0017] Furthermore, in step S5, polycrystalline diamond particles and diamond micro powder are mixed in a weight ratio between 1:5 and 1:1.

[0018] Furthermore, the cemented carbide matrix mentioned in step S6 is a cobalt-based tungsten carbide alloy.

[0019] The beneficial effects of this invention include: the diamond composite sheet prepared according to this method significantly improves wear resistance and impact resistance, the service life of the polycrystalline diamond layer is longer, and the connection stability between the diamond layer and the cemented carbide matrix is ​​also significantly improved. Attached Figure Description

[0020] Figure 1 This is a process flow diagram of the present invention;

[0021] Figure 2 This is a schematic diagram of the cross-sectional structure of the polycrystalline diamond composite sheet obtained by the present invention;

[0022] Figure 3 This is a graph showing the test results of the wear resistance and impact resistance of this invention. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0024] Example 1

[0025] A method for manufacturing polycrystalline diamond composite sheets, according to as follows: Figure 1 The process method shown specifically includes the following steps:

[0026] S1. Select diamond micro powder with a particle size of 1-30μm and mix it with the metal catalyst in a container at a weight ratio of 1:0.05; the metal catalyst is Co elemental powder.

[0027] S2. The container is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6Gpa-8Gpa to sinter diamond polycrystalline material.

[0028] S3. Diamond polycrystalline materials are laser-processed or mechanically processed to obtain polycrystalline particles with a particle size of 0.2mm-3mm;

[0029] S4. Metal removal treatment: Place the polycrystalline particles into a sealed container containing aqua regia with a concentration of 50%-80%, heat to 250℃, and react for 2-20 hours until the metal in the polycrystalline particles is completely dissolved. The residual metal can be detected by a magnetic measuring instrument. Finally, polycrystalline diamond particles with a particle size of 0.2-3mm are obtained.

[0030] S5. First, mix polycrystalline diamond particles with a particle size of 0.2-3mm and diamond micro powder with a particle size of 1-70μm at a weight ratio of 1:5. Then, place the mixture in a high-temperature resistant metal container and place the cemented carbide matrix on top. The cemented carbide matrix is ​​a Co-based WC alloy. The weight of the mixed diamond powder should be 1.5-3.5g according to the size of the cemented carbide matrix.

[0031] S6. The container from step S5 is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6.5Gpa-10Gpa for sintering to obtain a polycrystalline diamond composite sheet, the internal structure of which is as follows: Figure 2 As shown.

[0032] Abrasion resistance and impact resistance testing, such as Figure 3 As shown;

[0033] The impact resistance test was conducted using a drop hammer tester, and the target material was selected with a hardness of 58HRC and an impact absorption energy of 725J, which is about 20% higher than the 605J impact resistance of ordinary diamond composite sheets.

[0034] The wear resistance test was conducted by cutting hard granite on a vertical lathe. The wear ratio E was measured to be 8.1 million, which is 8% higher than that of ordinary diamond composite sheets (7.5 million).

[0035] Example 2

[0036] A method for manufacturing polycrystalline diamond composite sheets, such as Figure 1 The process method shown specifically includes the following steps:

[0037] S1. Select diamond micro powder with a particle size of 1-30μm and metal catalyst and mix them evenly in a container at a weight ratio of 1:0.2. The metal catalyst can be selected from Fe, Co and Ni elemental powders, or Fe, Co and Ni alloy powder, alloy particles or alloy sheets. In this embodiment, the element ratio of Fe and Co alloy is 95:5.

[0038] S2. The container is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6Gpa-8Gpa to sinter diamond polycrystalline material.

[0039] S3. Diamond polycrystalline materials are laser-processed or mechanically processed to obtain polycrystalline particles with a particle size of 0.2mm-3mm;

[0040] S4. Metal removal treatment: Place the polycrystalline particles into a sealed container containing an acid solution, which is a mixture of aqua regia and hydrofluoric acid in a ratio of 1:0.2 and a concentration of 50%-80%. Heat to 200°C and react for 2-20 hours until the metal in the polycrystalline particles is completely dissolved. The residual metal can be detected by a magnetic measuring instrument. Finally, polycrystalline diamond particles with a particle size of 0.2-3 mm are obtained.

[0041] S5. First, mix polycrystalline diamond particles with a particle size of 0.2-3mm and diamond micro powder with a particle size of 1-70μm thoroughly at a weight ratio of 1:1, then place them in a high-temperature resistant metal container, and place the cemented carbide substrate on top. The cemented carbide substrate is a Co-based WC alloy.

[0042] S6. The container from step S5 is placed in an environment with a temperature of 1400℃-1500℃ and a pressure of 6.5Gpa-10Gpa for sintering to obtain a polycrystalline diamond composite sheet, the internal structure of which is as follows: Figure 2 As shown.

[0043] Abrasion resistance and impact resistance testing

[0044] The impact resistance test was conducted using a drop hammer tester, and the target material was selected with a hardness of 58HRC and an impact absorption energy of 795J, which is about 31% higher than the 605J of ordinary diamond composite sheets.

[0045] The wear resistance test was conducted by cutting hard granite on a vertical lathe. The wear ratio E was measured to be 7.8 million, which is 4% higher than that of ordinary diamond composite sheets (7.5 million).

[0046] The technical solutions provided by the embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the embodiments of the present invention. The descriptions of the embodiments above are only for helping to understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the embodiments of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for manufacturing a polycrystalline diamond composite sheet, characterized in that: Includes the following steps: S1. Select diamond micro powder with a particle size of 1–70 μm and mix it evenly with a metal catalyst in a container. The metal catalyst is one or more of Fe, Co, and Ni. S2. The container is placed in an environment with a temperature of 1400℃–1500℃ and a pressure of 6GPa–8GPa for sintering to obtain polycrystalline diamond. S3. Diamond polycrystalline materials are laser-processed or mechanically processed to obtain polycrystalline particles with a particle size of 0.2mm–3mm; S4. Metal removal treatment: Place the polycrystalline particles into a sealed container containing an acid solution, which is aqua regia, hydrofluoric acid, or a mixture of the two. Heat to 50–250°C and react for 2–20 hours until the metal in the polycrystalline particles is completely dissolved to obtain polycrystalline diamond particles with a particle size of 0.2–3 mm. S5. Mix polycrystalline diamond particles with a particle size of 0.2–3 mm and diamond micro powder with a particle size of 1–70 μm at a weight ratio of 1:5 to 1:1 and place them in a high-temperature resistant metal container. Then place the cemented carbide matrix on top of the mixed powder and cover it with a metal lid. S6. The container from step S5 is placed in an environment with a temperature of 1400℃–1500℃ and a pressure of 6.5GPa–10GPa for sintering to obtain a polycrystalline diamond composite sheet.

2. The method for manufacturing a polycrystalline diamond composite sheet according to claim 1, characterized in that: In step S1, diamond micro powder and the metal catalyst are mixed at a weight ratio of 1:0.05 to 1:0.

20.

3. The method for manufacturing a polycrystalline diamond composite sheet according to claim 1, characterized in that: The metal catalyst exists in the form of elemental powder, alloy powder, alloy particles, or alloy flakes.

4. The method for manufacturing a polycrystalline diamond composite sheet according to claim 1, characterized in that: The concentration of the acid solution is 50%–80%.

5. The method for manufacturing a polycrystalline diamond composite sheet according to claim 1, characterized in that: The cemented carbide matrix mentioned in step S6 is a cobalt-based tungsten carbide alloy.

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