Polycrystalline diamond compact and preparation method thereof

Abstract

The invention discloses a polycrystalline diamond compact and a preparation method thereof, the polycrystalline diamond compact comprises a polycrystalline diamond layer and a hard alloy matrix arranged on the polycrystalline diamond layer, and the polycrystalline diamond layer comprises diamond micro-powder, an adhesive and a metal additive; wherein the heat conductivity coefficient of the metal additive is greater than 150W / (m.K). According to the invention, the metal additive with high heat-conducting property is introduced into the polycrystalline diamond layer, so that the heat-conducting property of the polycrystalline diamond layer is improved, sufficient heat dissipation is realized in the cutting process of the polycrystalline diamond compact, heat damage caused by high temperature is reduced, and the comprehensive performance of the polycrystalline diamond compact is improved.

Description

Technical Field

[0001] The present invention relates to the field of superhard materials, and in particular to a polycrystalline diamond composite sheet and a preparation method thereof. Background Art

[0002] Due to its high hardness and high toughness, polycrystalline diamond composite sheets are widely used in oil and gas extraction, cutting tools and other wear-resistant tools. The polycrystalline diamond composite sheet is sintered into one by a high-temperature and high-pressure synthesis process, in which the polycrystalline diamond layer is sintered by diamond micropowder under the action of an adhesive. During the operation of the polycrystalline diamond composite sheet, a large amount of heat is generated by long-term cutting friction, causing the temperature of the polycrystalline diamond composite sheet to rise. Under high temperature conditions, the adhesive distributed in the gaps of the polycrystalline diamond layer causes the diamond to graphitize, causing problems such as cracks and chipping. In addition, due to the large difference in the thermal expansion coefficients of the polycrystalline diamond layer and the cemented carbide substrate, high temperature can easily cause the polycrystalline diamond layer to fall off, which in turn causes the polycrystalline diamond composite sheet to fail.

[0003] In the polycrystalline diamond composite sheet used in oil and gas development, strong acid is used to remove the adhesive in the polycrystalline diamond layer (decobaltization process), which significantly improves the heat resistance of the polycrystalline diamond composite sheet and is widely used. At the same time, in order to improve thermal stability, the surface of diamond micropowder can be plated with titanium and other metals as a protective layer to reduce the direct contact between diamond and metal catalysts or oxygen, and improve the thermal stability of the polycrystalline diamond composite sheet. However, the appearance of the coating hinders the direct contact between diamond micropowders, making the diamond bonding effect worse and the wear resistance reduced. As the actual application conditions become more and more complex, the comprehensive performance of polycrystalline diamond composite sheets needs to be further improved to meet different usage requirements.

[0004] Therefore, the prior art still needs to be improved and developed. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a polycrystalline diamond composite sheet and a preparation method thereof, aiming to solve the problem that the existing polycrystalline diamond composite sheet has low thermal conductivity, which leads to easy cracking, chipping and even delamination during actual application.

[0006] The technical solution of the present invention is as follows:

[0007] In a first aspect of the present invention, a polycrystalline diamond compact is provided, the polycrystalline diamond compact comprising a polycrystalline diamond layer and a cemented carbide substrate disposed on the polycrystalline diamond layer, the polycrystalline diamond layer comprising diamond powder, an adhesive and a metal additive;

[0008] Wherein, the thermal conductivity of the metal additive is greater than 150 W / (m·K).

[0009] Preferably, in the polycrystalline diamond layer, the mass proportion of diamond powder is 90-99.5%, the mass proportion of adhesive is 0-10%, and the mass proportion of metal additive is 0.1-10%.

[0010] Preferably, in the polycrystalline diamond layer, the mass proportion of diamond powder is 95-99.5%, the mass proportion of adhesive is 0-5%, and the mass proportion of metal additive is 0.1-5%.

[0011] Preferably, the metal additive is a metal element, a metal oxide, a metal carbide, a metal nitride or a metal chloride;

[0012] Wherein, the metal is selected from one or more of silver, copper, gold and aluminum.

[0013] Preferably, the particle size of the metal additive is 0.1-10 microns.

[0014] Preferably, the adhesive is selected from one or more of iron, cobalt and nickel.

[0015] Preferably, the particle size of the diamond powder is 5-50 microns, and the particle size of the adhesive is 0.1-10 microns.

[0016] A second aspect of the present invention provides a method for preparing the above-mentioned polycrystalline diamond compact, the preparation method comprising the following steps:

[0017] Mixing diamond micropowder, adhesive and metal additive to obtain mixed powder;

[0018] placing a cemented carbide substrate on the mixed powder to obtain an assembly block;

[0019] The assembly block is sintered to obtain the polycrystalline diamond composite sheet.

[0020] Preferably, the sintering temperature is 1300-1800° C., the sintering pressure is 5-10 GPa, and the sintering time is 2-60 min.

[0021] Beneficial effects: The present invention discloses a polycrystalline diamond composite sheet and a preparation method thereof. The present invention improves the thermal conductivity of the polycrystalline diamond layer by introducing a metal additive with high thermal conductivity into the polycrystalline diamond layer, so that the cutting process of the polycrystalline diamond composite sheet can obtain sufficient heat dissipation, reduce thermal damage caused by high temperature, and improve the comprehensive performance of the polycrystalline diamond composite sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1A schematic cross-sectional structure diagram of a polycrystalline diamond composite sheet provided in a preferred embodiment of the present invention, wherein 1 is a polycrystalline diamond layer and 2 is a cemented carbide substrate. DETAILED DESCRIPTION

[0023] The present invention provides a polycrystalline diamond composite sheet and a preparation method thereof. To make the purpose, technical solution and effect of the present invention clearer and more specific, 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.

[0024] The embodiment of the present invention provides a polycrystalline diamond composite sheet, such as Figure 1 As shown, the polycrystalline diamond composite sheet includes a polycrystalline diamond layer and a cemented carbide substrate disposed on the polycrystalline diamond layer, and the polycrystalline diamond layer includes diamond powder, an adhesive and a metal additive;

[0025] Wherein, the thermal conductivity of the metal additive is greater than 150 W / (m·K).

[0026] The embodiments of the present invention improve the heat dissipation performance of the polycrystalline diamond composite sheet by introducing metal additives with high thermal conductivity to improve the thermal conductivity of the polycrystalline diamond layer, improve the heat dissipation capacity of the polycrystalline diamond composite sheet during operation, reduce the operating temperature of the polycrystalline diamond composite sheet, and improve the comprehensive performance of the polycrystalline diamond composite sheet.

[0027] Diamond powder has high thermal conductivity, but the adhesive distributed in the diamond powder skeleton has poor thermal conductivity, which limits the overall thermal conductivity of the polycrystalline diamond layer. Compared with the adhesive, the metal additive in the present invention has a higher thermal conductivity coefficient and better thermal conductivity. The metal additive with high thermal conductivity distributed in the polycrystalline diamond layer can improve the overall thermal conductivity of the polycrystalline diamond layer.

[0028] In some embodiments, in the polycrystalline diamond layer, the mass proportion of diamond powder is 90-99.5%, the mass proportion of adhesive is 0-10%, and the mass proportion of metal additive is 0.1-10%.

[0029] The addition ratio of diamond powder, adhesive and metal additives is crucial to the performance of polycrystalline diamond composite sheets. During the high temperature and high pressure synthesis process, the diamond powders are in contact and extruded with each other, and diamond-diamond bonds are formed under the action of the adhesive, and the polycrystalline diamond layer is sintered. After being fully mixed with the diamond powder, the adhesive or metal additive exists between the diamond powders, which to a certain extent hinders the direct contact between the diamond powders and affects the bonding effect of the diamond powders. Therefore, the addition ratio of the adhesive or metal additive needs to be controlled within an appropriate range. Too high an addition ratio is likely to cause the bonding effect of the diamond powder to deteriorate, thereby causing the performance of the polycrystalline diamond layer to deteriorate.

[0030] In some preferred embodiments, in the polycrystalline diamond layer, the mass proportion of diamond powder is 95-99.5%, the mass proportion of adhesive is 0-5%, and the mass proportion of metal additive is 0.1-5%.

[0031] In some embodiments, the metal additive is a metal element, a metal oxide, a metal carbide, a metal nitride or a metal chloride;

[0032] Wherein, the metal is selected from one or more of silver, copper, gold and aluminum.

[0033] In some embodiments, the particle size of the metal additive is 0.1-10 microns.

[0034] The appropriate particle size range of the metal additive can make the diamond powder and the metal additive mixed more fully and evenly, and will not affect the bonding effect of the diamond powder during the high temperature and high pressure synthesis process, thereby ensuring the quality of the polycrystalline diamond layer.

[0035] In some preferred embodiments, the particle size of the metal additive is 0.1-5 microns.

[0036] In some embodiments, the binder is selected from one or more of iron, cobalt, and nickel.

[0037] In some embodiments, the particle size of the diamond powder is 5-50 microns, and the particle size of the adhesive is 0.1-10 microns.

[0038] In some preferred embodiments, the particle size of the adhesive is 0.1-5 microns.

[0039] The embodiment of the present invention also provides a method for preparing the above-mentioned polycrystalline diamond compact, the preparation method comprising the following steps:

[0040] Mixing diamond micropowder, adhesive and metal additive to obtain mixed powder;

[0041] placing a cemented carbide substrate on the mixed powder to obtain an assembly block;

[0042] The assembly block is sintered to obtain the polycrystalline diamond composite sheet.

[0043] In some embodiments, the sintering temperature is 1300-1800° C., the sintering pressure is 5-10 GPa, and the sintering time is 2-60 min.

[0044] 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 the embodiments, and are only for illustrating the present invention but not limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0045] Example 1

[0046] A preparation method of a polycrystalline diamond composite sheet comprises the following steps:

[0047] Diamond powder with an average particle size of 25 microns, cobalt powder with an average particle size of 5 microns and silver powder with an average particle size of 3 microns are fully and uniformly mixed to obtain a mixture, wherein the mass ratio of diamond powder, cobalt powder and silver powder is 95:2.5:2.5;

[0048] sequentially placing the mixed material and the cemented carbide substrate into a metal cup to obtain a metal cup assembly block;

[0049] The metal cup assembly block was sintered under high temperature and high pressure conditions of synthesis pressure of 8 GPa and temperature of 1500° C. for 15 minutes to obtain a polycrystalline diamond composite sheet.

[0050] Example 2

[0051] A preparation method of a polycrystalline diamond composite sheet comprises the following steps:

[0052] Diamond powder with an average particle size of 25 microns, cobalt powder with an average particle size of 5 microns and silver oxide powder with an average particle size of 5 microns are fully mixed to obtain a mixture, wherein the mass ratio of the diamond powder, the cobalt powder and the silver oxide powder is 95:2.5:2.5;

[0053] sequentially placing the mixed material and the cemented carbide substrate into a metal cup to obtain a metal cup assembly block;

[0054] The metal cup assembly block was sintered under high temperature and high pressure conditions of synthesis pressure of 8 GPa and temperature of 1500° C. for 15 minutes to obtain a polycrystalline diamond composite sheet.

[0055] Example 3

[0056] A preparation method of a polycrystalline diamond composite sheet comprises the following steps:

[0057] Diamond powder with an average particle size of 25 microns, cobalt powder with an average particle size of 5 microns and copper powder with an average particle size of 2 microns are fully mixed to obtain a mixture, wherein the mass ratio of diamond powder, cobalt powder and copper powder is 95:2.5:2.5;

[0058] sequentially placing the mixed material and the cemented carbide substrate into a metal cup to obtain a metal cup assembly block;

[0059] The metal cup assembly block was sintered under high temperature and high pressure conditions of synthesis pressure of 8 GPa and temperature of 1500° C. for 15 minutes to obtain a polycrystalline diamond composite sheet.

[0060] Comparative Example 1

[0061] A preparation method of a polycrystalline diamond composite sheet comprises the following steps:

[0062] The diamond powder with an average particle size of 25 microns and the cobalt powder with an average particle size of 5 microns are fully mixed to obtain a mixture, wherein the mass ratio of the diamond powder to the cobalt powder is 95:5;

[0063] sequentially placing the mixed material and the cemented carbide substrate into a metal cup to obtain a metal cup assembly block;

[0064] The metal cup assembly block was sintered under high temperature and high pressure conditions of synthesis pressure of 8 GPa and temperature of 1500° C. for 15 minutes to obtain a polycrystalline diamond composite sheet.

[0065] Comparative Example 2

[0066] A preparation method of a polycrystalline diamond composite sheet comprises the following steps:

[0067] Diamond powder with an average particle size of 25 microns, cobalt powder with an average particle size of 5 microns, and silver powder with an average particle size of 3 microns are fully mixed to obtain a mixture, wherein the mass ratio of the diamond powder, the cobalt powder, and the silver powder is 60:20:20;

[0068] sequentially placing the mixed material and the cemented carbide substrate into a metal cup to obtain a metal cup assembly block;

[0069] The metal cup assembly block was sintered under high temperature and high pressure conditions of synthesis pressure of 8 GPa and temperature of 1500° C. for 15 minutes to obtain a polycrystalline diamond composite sheet.

[0070] The polycrystalline diamond composite sheets obtained in the above embodiments and comparative examples were subjected to wear resistance and heat resistance tests. The wear resistance test was based on a vertical lathe, using the polycrystalline diamond composite sheet to grind granite, and the wear ratio was obtained based on the ratio of the wear volume of the granite and the polycrystalline diamond composite sheet. The heat resistance test was based on measuring the maximum temperature when the polycrystalline diamond layer of the polycrystalline diamond composite sheet was damaged. The results are as follows:

[0071] The wear ratio of the polycrystalline diamond composite sheet prepared in Example 1 is 1.55 million, and the heat resistance temperature is 853°C. The wear ratio of the polycrystalline diamond composite sheet prepared in Example 2 is 1.42 million, and the heat resistance temperature is 841°C. The wear ratio of the polycrystalline diamond composite sheet prepared in Example 3 is 1.38 million, and the heat resistance temperature is 839°C.

[0072] The polycrystalline diamond composite sheet prepared in comparative example 1 has an abrasion ratio of 1.22 million and a heat-resistant temperature of 816°C. The polycrystalline diamond composite sheet prepared in comparative example 2 has an abrasion ratio of 650,000 and a heat-resistant temperature of 804°C.

[0073] It can be seen from the above test results that the wear resistance and heat resistance of the polycrystalline diamond composite sheet prepared in the embodiment of the present invention are improved compared with the comparative example.

[0074] 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 polycrystalline diamond compact, comprising a polycrystalline diamond layer and a cemented carbide substrate disposed on the polycrystalline diamond layer, characterized in that: The polycrystalline diamond layer comprises diamond powder, adhesive and metal additives; Wherein, the thermal conductivity of the metal additive is greater than 150 W / (m·K).

2. The polycrystalline diamond compact according to claim 1, characterized in that: In the polycrystalline diamond layer, the mass proportion of diamond powder is 90-99.5%, the mass proportion of adhesive is 0-10%, and the mass proportion of metal additive is 0.1-10%.

3. The polycrystalline diamond compact according to claim 1, characterized in that: In the polycrystalline diamond layer, the mass proportion of diamond powder is 95-99.5%, the mass proportion of adhesive is 0-5%, and the mass proportion of metal additive is 0.1-5%.

4. The polycrystalline diamond compact according to claim 1, characterized in that: The metal additive is a metal element, metal oxide, metal carbide, metal nitride or metal chloride; Wherein, the metal is selected from one or more of silver, copper, gold and aluminum.

5. The polycrystalline diamond compact according to claim 1, characterized in that: The particle size of the metal additive is 0.1-10 microns.

6. The polycrystalline diamond compact according to claim 1, characterized in that: The adhesive is selected from one or more of iron, cobalt and nickel.

7. The polycrystalline diamond compact according to claim 1, characterized in that: The particle size of the diamond micropowder is 5-50 microns, and the particle size of the adhesive is 0.1-10 microns.

8. A method for preparing a polycrystalline diamond compact according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: Mixing diamond micropowder, adhesive and metal additive to obtain mixed powder; placing a cemented carbide substrate on the mixed powder to obtain an assembly block; The assembly block is sintered to obtain the polycrystalline diamond composite sheet.

9. The method for preparing a polycrystalline diamond compact according to claim 8, characterized in that: The sintering temperature is 1300-1800° C., the sintering pressure is 5-10 GPa, and the sintering time is 2-60 min.

Images