Non-magnetic polycrystalline diamond compact as well as preparation method and application thereof

Abstract

The invention relates to the technical field of superhard materials, and discloses a non-magnetic polycrystalline diamond compact as well as a preparation method and application thereof. The non-magnetic polycrystalline diamond compact comprises a nickel-based hard alloy matrix and a polycrystalline diamond layer compounded on the nickel-based hard alloy matrix, wherein the nickel-based hard alloy matrix comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond micro powder. According to the non-magnetic polycrystalline diamond compact, the nickel-based hard alloy matrix is used, and the polycrystalline diamond layer takes nickel as a binding phase, so that the magnetism of the polycrystalline diamond compact is effectively reduced, and the application requirement of a non-magnetic bearing material can be met.

Description

Technical Field

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

[0002] As an important component in mechanical equipment, bearings are widely used in different fields such as metallurgy, wind power, automobiles and aerospace. In some special application scenarios, in addition to high hardness and wear resistance, bearing materials also need to be non-magnetic to avoid magnetism affecting the normal operation and system sensitivity of high-end equipment. Polycrystalline diamond composite sheets are also gradually used in bearings due to their excellent wear resistance to increase the service life of bearings. However, conventional polycrystalline diamond composite sheets involve a cobalt-based cemented carbide matrix, and cobalt is often used as a diamond binder, which makes polycrystalline diamond composite sheets inevitably magnetic and cannot meet the application requirements of non-magnetic bearings.

[0003] Therefore, the existing technology still needs to be improved and developed. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a non-magnetic polycrystalline diamond compact and a preparation method and application thereof, aiming to solve the problem of the lack of non-magnetic polycrystalline diamond compact in the prior art.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, a non-magnetic polycrystalline diamond composite sheet is provided, comprising a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate;

[0007] Wherein, the nickel-based cemented carbide substrate comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond powder.

[0008] According to a preferred technical solution, in the nickel-based cemented carbide substrate, the mass percentage of nickel is 5-20%, and the mass percentage of tungsten carbide is 80-95%.

[0009] According to a preferred technical solution, in the polycrystalline diamond layer, the mass percentage of nickel is 1-10%, and the mass percentage of diamond powder is 90-99%.

[0010] According to a preferred technical solution, the coercive force of the nickel-based cemented carbide substrate is 0 to 25 Oe.

[0011] According to a preferred technical solution, the average particle size of the diamond powder is 1 to 100 microns.

[0012] In a second aspect, a method for preparing the non-magnetic polycrystalline diamond compact as described in the first aspect is provided, comprising the steps of:

[0013] Diamond micropowders of different particle sizes are mixed evenly to obtain a mixture; or diamond micropowders of different particle sizes and a binder are mixed evenly to obtain a mixture;

[0014] The mixed material and the nickel-based cemented carbide matrix are placed in a mold, and subjected to sintering treatment to obtain the non-magnetic polycrystalline diamond composite sheet;

[0015] Wherein, the binder is nickel or nickel oxide.

[0016] According to a preferred technical solution, in the mixture, the mass percentage of the diamond powder is 85-100%, and the mass percentage of the binder is 0-15%.

[0017] According to a preferred technical solution, the average particle size of the binder is 0.1 to 10 microns.

[0018] According to a preferred technical solution, the mold is a metal cup.

[0019] According to a further preferred technical solution, the metal cup is made of niobium, zirconium, molybdenum or tantalum.

[0020] According to a preferred technical solution, the sintering treatment conditions include: synthesis pressure of 5 to 10 GPa, temperature of 1400 to 2000° C., and time of 2 to 60 min.

[0021] In a third aspect, there is provided a use of the non-magnetic polycrystalline diamond composite sheet as described in the first aspect or the non-magnetic polycrystalline diamond composite sheet prepared by the preparation method as described in the second aspect in preparing bearings.

[0022] Beneficial effects: In the prior art, there are few reports on non-magnetic polycrystalline diamond composite sheets, which cannot meet the application requirements of non-magnetic bearing materials. The present invention provides a non-magnetic polycrystalline diamond composite sheet, which uses nickel-based cemented carbide as a matrix and nickel as a bonding phase of a polycrystalline diamond layer to effectively reduce the magnetism of the polycrystalline diamond composite sheet and achieve non-magnetization of the polycrystalline diamond composite sheet, thereby meeting the application requirements of non-magnetic bearing materials. DETAILED DESCRIPTION

[0023] The present invention provides a non-magnetic polycrystalline diamond composite sheet and a preparation method and application thereof. In order to make the purpose, technical scheme and effect of the present invention clearer and more specific, the present invention is further described in detail below.

[0024] Polycrystalline diamond composite sheets are gradually being used as bearing materials due to their high wear resistance to increase the service life of bearing parts. Polycrystalline diamond composite sheets are prepared by sintering diamond micropowder and cemented carbide matrix under high temperature and high pressure. For the cemented carbide matrix, cobalt-based cemented carbide matrix is ​​widely used in polycrystalline diamond composite sheets due to its excellent toughness. For the sintering of diamond micropowder, cobalt is often used as a binder for polycrystalline diamond layer due to its good catalytic effect on diamond. However, due to the high Curie temperature of cobalt, the presence of cobalt makes polycrystalline diamond composite sheets inevitably magnetic and cannot meet the non-magnetic application requirements of bearing materials. Compared with cobalt, nickel has a lower Curie temperature and also has a diamond catalytic effect, which provides the possibility for non-magnetic polycrystalline diamond composite sheets.

[0025] Based on this, an embodiment of the present invention provides a non-magnetic polycrystalline diamond composite sheet. In a first aspect, a non-magnetic polycrystalline diamond composite sheet is provided, comprising a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate;

[0026] Wherein, the nickel-based cemented carbide substrate comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond powder.

[0027] This embodiment uses a nickel-based cemented carbide substrate including nickel and tungsten carbide to replace the commonly used cobalt-based cemented carbide substrate, and uses the nickel in the nickel-based cemented carbide substrate or the additionally added nickel as the bonding component of the polycrystalline diamond layer, so that the diamond powder is compounded on the nickel-based cemented carbide substrate to form a polycrystalline diamond layer, thereby obtaining a non-magnetized polycrystalline diamond composite sheet.

[0028] In one embodiment, in the nickel-based cemented carbide matrix, the mass percentage of nickel is 5-20%, and the mass percentage of tungsten carbide is 80-95%, but it is not limited thereto, and the ratio of nickel to tungsten carbide can be adjusted according to actual needs. It is understandable that the nickel-based cemented carbide matrix can also contain other substances with a coercive force <25Oe.

[0029] In one embodiment, in the polycrystalline diamond layer, the mass percentage of nickel is 1-10%, and the mass percentage of diamond powder is 90-99%, but it is not limited thereto, and the ratio of nickel to diamond powder can be adjusted according to actual needs. It is understandable that the polycrystalline diamond layer can also contain other substances with a coercive force <25Oe.

[0030] In one embodiment, the coercive force of the nickel-based cemented carbide substrate is 0 to 25 Oe.

[0031] In one embodiment, the average particle size of the diamond powder is 1 to 100 microns, but is not limited thereto. The average particle size of the diamond powder can be adjusted according to actual needs.

[0032] Based on the same inventive concept, an embodiment of the present invention provides a method for preparing the non-magnetic polycrystalline diamond compact as described above, comprising the steps of:

[0033] Diamond micropowders of different particle sizes are mixed evenly to obtain a mixture; or diamond micropowders of different particle sizes and a binder are mixed evenly to obtain a mixture;

[0034] The mixed material and the nickel-based cemented carbide matrix are placed in a mold, and subjected to sintering treatment to obtain the non-magnetic polycrystalline diamond composite sheet;

[0035] Wherein, the binder is nickel or nickel oxide.

[0036] Specifically, under high temperature and high pressure sintering conditions, the nickel in the nickel-based cemented carbide matrix melts and then penetrates into the diamond layer, catalyzing the formation of DD bonds between the diamond powders, and sintering to form a polycrystalline diamond layer. In addition, nickel or nickel oxide may be added to the diamond powder formula to help the diamond powder sinter better to form a polycrystalline diamond layer. Therefore, the preparation method of this embodiment may include or not include a binder.

[0037] In one embodiment, in the mixture, the mass percentage of the diamond powder is 85-100%, and the mass percentage of the binder is 0-15%, but it is not limited thereto, and the ratio of the diamond powder to the binder can be adjusted according to actual needs. It is understandable that the mass ratio of the diamond powder and the binder added during the preparation process is not completely the same as the mass ratio of the diamond powder and the nickel in the polycrystalline diamond layer finally prepared. The reason is: on the one hand, the nickel-based cemented carbide matrix will melt nickel during the sintering process, providing a nickel source for the sintering and bonding of the diamond powder, thereby increasing the mass ratio of nickel in the polycrystalline diamond layer; on the other hand, when additional nickel or nickel oxide is added as a binder, the added binder can also enter the nickel-based cemented carbide matrix to form a redistribution of the nickel content.

[0038] In one embodiment, the average particle size of the binder is 0.1 to 10 microns, but is not limited thereto. The average particle size of the binder can be adjusted according to actual needs.

[0039] In one embodiment, the mold is a metal cup, but is not limited thereto.

[0040] In a more specific embodiment, the material of the metal cup is niobium, zirconium, molybdenum or tantalum, but is not limited thereto. The material of the metal cup can be adjusted according to actual needs.

[0041] In one embodiment, the sintering treatment conditions include: synthesis pressure 5-10 GPa, temperature 1400-2000° C., and time 2-60 min, but are not limited thereto. The sintering treatment conditions can be adjusted according to actual needs.

[0042] An embodiment of the present invention further provides a use of the non-magnetic polycrystalline diamond compact as described above or the non-magnetic polycrystalline diamond compact prepared by the preparation method as described above in preparing a bearing.

[0043] The present invention will be further described below by means of specific examples.

[0044] Comparative Example

[0045] This comparative example provides a polycrystalline diamond composite sheet, including a cobalt-based cemented carbide substrate and a polycrystalline diamond layer composited on the cobalt-based cemented carbide substrate. The polycrystalline diamond layer is prepared from diamond micropowder and cobalt powder, wherein the average particle size of the diamond micropowder is 15 microns, accounting for 95% by mass, and the average particle size of the cobalt powder is 1 micron, accounting for 5% by mass. The cemented carbide substrate is a cobalt-based cemented carbide substrate, wherein the mass proportion of cobalt is 13%, the mass proportion of tungsten carbide is 87%, and the coercive force is 125Oe. The preparation method of the polycrystalline diamond composite sheet is as follows:

[0046] (1) fully and uniformly mixing diamond micropowder and cobalt powder of different particle sizes to obtain a diamond micropowder mixture;

[0047] (2) sequentially placing a diamond powder mixture and a cobalt-based cemented carbide substrate into a metal cup to obtain a metal cup assembly;

[0048] (3) The metal cup assembly was sintered at a synthesis pressure of 8 GPa and a temperature of 1500° C. for 15 min to obtain a polycrystalline diamond composite sheet.

[0049] The polycrystalline diamond composite sheet of this comparative example has a grinding wheel wear ratio test result of 440,000 and a coercive force test result of 118 Oe.

[0050] Example 1

[0051] This embodiment provides a non-magnetic polycrystalline diamond composite sheet, including a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate. The polycrystalline diamond layer is prepared only from diamond micropowder, and the average particle size of the diamond micropowder is 15 microns. The cemented carbide substrate is a nickel-based cemented carbide substrate, in which the mass proportion of nickel is 13%, the mass proportion of tungsten carbide is 87%, and its coercive force is 0Oe. ​​The preparation method of the non-magnetic polycrystalline diamond composite sheet is as follows:

[0052] (1) fully and uniformly mixing diamond micropowders of different particle sizes to obtain a diamond micropowder mixture;

[0053] (2) sequentially placing a diamond powder mixture and a nickel-based cemented carbide substrate into a metal cup to obtain a metal cup assembly;

[0054] (3) The metal cup assembly was sintered at a synthesis pressure of 8 GPa and a temperature of 1650° C. for 15 min to obtain a non-magnetic polycrystalline diamond composite sheet.

[0055] The non-magnetic polycrystalline diamond composite sheet of this embodiment has a grinding wheel wear ratio test result of 510,000 and a coercive force test result of 0 Oe. Compared with the comparative example, the magnetic properties of this embodiment are significantly reduced, and the polycrystalline diamond composite sheet can be non-magnetized.

[0056] Example 2

[0057] This embodiment provides a non-magnetic polycrystalline diamond composite sheet, including a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate. The polycrystalline diamond layer is composed of diamond micropowder and nickel powder, wherein the average particle size of the diamond micropowder is 15 microns, accounting for 95% by mass, and the average particle size of the nickel powder is 1 micron, accounting for 5% by mass. The cemented carbide substrate is a nickel-based cemented carbide substrate, wherein the mass of nickel accounts for 13%, the mass of tungsten carbide accounts for 87%, and its coercive force is 0Oe. ​​The preparation method of the non-magnetic polycrystalline diamond composite sheet is as follows:

[0058] (1) fully and uniformly mixing diamond micropowder and nickel powder of different particle sizes to obtain a diamond micropowder mixture;

[0059] (2) sequentially placing a diamond powder mixture and a nickel-based cemented carbide substrate into a metal cup to obtain a metal cup assembly;

[0060] (3) The metal cup assembly was sintered at a synthesis pressure of 7 GPa and a temperature of 1600° C. for 20 min to obtain a non-magnetic polycrystalline diamond composite sheet.

[0061] The polycrystalline diamond composite sheet of this embodiment has a grinding wheel wear ratio test result of 390,000 and a coercive force test result of 0 Oe. Compared with the comparative example, the magnetic properties of this embodiment are significantly reduced, and the polycrystalline diamond composite sheet can be non-magnetized.

[0062] In summary, the present invention provides a non-magnetic polycrystalline diamond composite sheet and its preparation method and application. The non-magnetic polycrystalline diamond composite sheet includes a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate; wherein the nickel-based cemented carbide substrate includes nickel and tungsten carbide, and the polycrystalline diamond layer includes nickel and diamond powder. The non-magnetic polycrystalline diamond composite sheet of the present invention uses a nickel-based cemented carbide substrate and nickel as a bonding phase for the polycrystalline diamond layer, which effectively reduces the magnetism of the polycrystalline diamond composite sheet, and has high wear resistance and non-magnetism, which can meet the application requirements of non-magnetic bearing materials.

[0063] 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 non-magnetic polycrystalline diamond composite sheet, characterized in that: It comprises a nickel-based cemented carbide substrate and a polycrystalline diamond layer composited on the nickel-based cemented carbide substrate; Wherein, the nickel-based cemented carbide substrate comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond powder.

2. The non-magnetic polycrystalline diamond compact according to claim 1, characterized in that: In the nickel-based cemented carbide matrix, the mass percentage of nickel is 5-20%, and the mass percentage of tungsten carbide is 80-95%; And / or, in the polycrystalline diamond layer, the mass percentage of nickel is 1-10%, and the mass percentage of diamond powder is 90-99%.

3. The non-magnetic polycrystalline diamond compact according to claim 1, characterized in that: The coercive force of the nickel-based cemented carbide substrate is 0 to 25 Oe.

4. The non-magnetic polycrystalline diamond compact according to claim 1, characterized in that: The average particle size of the diamond powder is 1 to 100 microns.

5. A method for preparing a non-magnetic polycrystalline diamond compact according to any one of claims 1 to 4, characterized in that: Includes steps: Diamond micropowders of different particle sizes are mixed evenly to obtain a mixture; or diamond micropowders of different particle sizes and a binder are mixed evenly to obtain a mixture; The mixed material and the nickel-based cemented carbide matrix are placed in a mold, and subjected to sintering treatment to obtain the non-magnetic polycrystalline diamond composite sheet; Wherein, the binder is nickel or nickel oxide.

6. The preparation method according to claim 5, characterized in that: In the mixture, the mass percentage of the diamond powder is 85-100%, and the mass percentage of the binder is 0-15%; And / or, the average particle size of the binder is 0.1 to 10 microns.

7. The preparation method according to claim 5, characterized in that: The mold is a metal cup.

8. The preparation method according to claim 7, characterized in that: The metal cup is made of niobium, zirconium, molybdenum or tantalum.

9. The preparation method according to claim 5, characterized in that: The sintering treatment conditions include: synthesis pressure of 5 to 10 GPa, temperature of 1400 to 2000° C., and time of 2 to 60 min.

10. Use of the non-magnetic polycrystalline diamond compact as claimed in any one of claims 1 to 4 or the non-magnetic polycrystalline diamond compact prepared by the preparation method as claimed in any one of claims 5 to 9 in the preparation of bearings.