A non-magnetic polycrystalline diamond compact and a preparation method and application thereof

Abstract

The application 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 base and a polycrystalline diamond layer combined on the nickel-based hard alloy base; wherein the nickel-based hard alloy base comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond micro powder. The non-magnetic polycrystalline diamond compact of the application uses a nickel-based hard alloy base, and the polycrystalline diamond layer uses nickel as a bonding 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] This invention relates to the field of superhard materials technology, and in particular to a non-magnetic polycrystalline diamond composite sheet, its preparation method, and its application. Background Technology

[0002] As crucial components in mechanical equipment, bearings are widely used in various fields such as metallurgy, wind power, automotive, and aerospace. In some specialized applications, bearing materials, in addition to requiring high hardness and wear resistance, also need to be non-magnetic to prevent magnetic interference with the normal operation and system sensitivity of high-end equipment. Polycrystalline diamond composite sheets, due to their excellent wear resistance, are increasingly being used in bearings to improve their service life. However, conventional polycrystalline diamond composite sheets involve a cobalt-based cemented carbide matrix, and cobalt is commonly used as a diamond binder, making the polycrystalline diamond composite sheets inevitably magnetic, which fails to meet the requirements for non-magnetic bearing applications.

[0003] Therefore, existing technologies still need improvement and development. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a non-magnetic polycrystalline diamond composite sheet, its preparation method and application, in order to solve the problem of the lack of non-magnetic polycrystalline diamond composite sheets 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 matrix and a polycrystalline diamond layer composited on the nickel-based cemented carbide matrix;

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

[0008] In a preferred embodiment, the nickel-based cemented carbide matrix contains 5-20% nickel by mass and 80-95% tungsten carbide by mass.

[0009] In a preferred embodiment, the mass percentage of nickel in the polycrystalline diamond layer is 1-10%, and the mass percentage of diamond micropowder is 90-99%.

[0010] In a preferred embodiment, the coercivity of the nickel-based cemented carbide matrix is ​​0–25 Oe.

[0011] In a preferred embodiment, the average particle size of the diamond powder is 1 to 100 micrometers.

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

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

[0014] The mixture and the nickel-based cemented carbide matrix are loaded into a mold and sintered to obtain the non-magnetic polycrystalline diamond composite sheet.

[0015] The binder is nickel or nickel oxide.

[0016] In a preferred embodiment, the mass percentage of the diamond micro powder in the mixture is 85-100%, and the mass percentage of the binder is 0-15%.

[0017] In a preferred embodiment, the average particle size of the adhesive is 0.1 to 10 micrometers.

[0018] In a preferred embodiment, the mold is a metal cup.

[0019] In a further preferred embodiment, the metal cup is made of niobium, zirconium, molybdenum, or tantalum.

[0020] In the preferred embodiment, the sintering conditions include: a synthesis pressure of 5–10 GPa, a temperature of 1400–2000 °C, and a time of 2–60 min.

[0021] Thirdly, the application of a non-magnetic polycrystalline diamond composite sheet as described in the first aspect or a non-magnetic polycrystalline diamond composite sheet prepared by the preparation method described in the second aspect in the preparation of bearings.

[0022] Beneficial Effects: Existing technologies rarely report on non-magnetic polycrystalline diamond composite sheets, failing to meet the application requirements of non-magnetic bearing materials. This invention provides a non-magnetic polycrystalline diamond composite sheet that effectively reduces the magnetism of the polycrystalline diamond composite sheet by using a nickel-based cemented carbide as the matrix and nickel as the binder phase for the polycrystalline diamond layer, thus achieving non-magnetization and meeting the application requirements of non-magnetic bearing materials. Detailed Implementation

[0023] This invention provides a non-magnetic polycrystalline diamond composite sheet, its preparation method, and its application. To make the purpose, technical solution, and effects of this invention clearer and more explicit, the invention is further described in detail below.

[0024] Polycrystalline diamond (PCD) composites, due to their high wear resistance, are increasingly being used as bearing materials to extend the service life of bearing components. PCD composites are prepared by sintering diamond micropowder and a cemented carbide matrix under high temperature and pressure. For the cemented carbide matrix, cobalt-based cemented carbide matrices are widely used in PCD composites due to their excellent toughness. For diamond micropowder sintering, cobalt is often used as a binder for the PCD layer because of its good catalytic effect on diamond. However, due to cobalt's high Curie temperature, the presence of cobalt inevitably makes PCD composites magnetic, which cannot meet the requirements for non-magnetic applications in bearings. Compared to cobalt, nickel has a lower Curie temperature and also possesses the catalytic effect of diamond, making non-magnetic PCD composites a possibility.

[0025] Based on this, embodiments of the present invention provide 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 matrix and a polycrystalline diamond layer composited on the nickel-based cemented carbide matrix.

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

[0027] In this embodiment, a nickel-based cemented carbide matrix including nickel and tungsten carbide is used instead of the commonly used cobalt-based cemented carbide matrix. Nickel in the nickel-based cemented carbide matrix or additional nickel is used as the binder of the polycrystalline diamond layer, so that diamond micropowder is composited on the nickel-based cemented carbide matrix to form a polycrystalline diamond layer, thereby obtaining a non-magnetized polycrystalline diamond composite sheet.

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

[0029] In one embodiment, the polycrystalline diamond layer contains 1-10% nickel by mass and 90-99% diamond micropowder by mass, but is not limited thereto; the ratio of nickel to diamond micropowder can be adjusted according to actual needs. It is understood that the polycrystalline diamond layer may also contain other substances with a coercivity <25 Oe.

[0030] In one embodiment, the coercivity of the nickel-based cemented carbide matrix is ​​0 to 25 Oe.

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

[0032] Based on the same inventive concept, embodiments of the present invention provide a method for preparing the non-magnetic polycrystalline diamond composite sheet as described above, comprising the following steps:

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

[0034] The mixture and the nickel-based cemented carbide matrix are loaded into a mold and sintered to obtain the non-magnetic polycrystalline diamond composite sheet.

[0035] The binder is nickel or nickel oxide.

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

[0037] In one embodiment, the mass percentage of the diamond micropowder in the mixture is 85-100%, and the mass percentage of the binder is 0-15%, but not limited thereto. The ratio of diamond micropowder to binder can be adjusted according to actual needs. It is understood that the mass ratio of diamond micropowder and binder added during the preparation process is not entirely equivalent to the mass ratio of diamond micropowder and nickel in the final polycrystalline diamond layer. This is because: on the one hand, nickel melts from the nickel-based cemented carbide matrix during sintering, providing a nickel source for the sintering and bonding of the diamond micropowder, thereby increasing the mass percentage 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, resulting in a redistribution of nickel content.

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

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

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

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

[0042] This invention also provides an application of the non-magnetic polycrystalline diamond composite sheet as described above or the non-magnetic polycrystalline diamond composite sheet prepared by the preparation method described above in the preparation of bearings.

[0043] The present invention will be further described below through specific embodiments.

[0044] Comparative Example

[0045] This comparative example provides a polycrystalline diamond composite sheet, comprising a cobalt-based cemented carbide matrix and a polycrystalline diamond layer composited on the cobalt-based cemented carbide matrix. The polycrystalline diamond layer is prepared from diamond micron powder and cobalt powder, wherein the diamond micron powder has an average particle size of 15 micrometers and accounts for 95% by mass, while the cobalt powder has an average particle size of 1 micrometer and accounts for 5% by mass. The cemented carbide matrix is ​​a cobalt-based cemented carbide matrix, wherein the cobalt accounts for 13% by mass, the tungsten carbide accounts for 87% by mass, and the coercivity is 125 Oe. The preparation method of the polycrystalline diamond composite sheet is as follows:

[0046] (1) After thoroughly mixing diamond micro powder and cobalt powder of different particle sizes, a diamond micro powder mixture is obtained;

[0047] (2) Diamond micro powder mixture and cobalt-based cemented carbide matrix are sequentially loaded into a metal cup to obtain a metal cup assembly;

[0048] (3) The metal cup assembly was sintered for 15 minutes under high temperature and high pressure conditions of 8 GPa and 1500℃ to obtain polycrystalline diamond composite sheet.

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

[0050] Example 1

[0051] This embodiment provides a non-magnetic polycrystalline diamond composite sheet, comprising a nickel-based cemented carbide matrix and a polycrystalline diamond layer composited on the nickel-based cemented carbide matrix. The polycrystalline diamond layer is prepared solely from diamond micron powder, with an average particle size of 15 micrometers. The cemented carbide matrix is ​​a nickel-based cemented carbide matrix, wherein nickel accounts for 13% by mass and tungsten carbide accounts for 87% by mass, and its coercivity is 0 Oe. The preparation method of the non-magnetic polycrystalline diamond composite sheet is as follows:

[0052] (1) After thoroughly mixing diamond micro powders of different particle sizes, a diamond micro powder mixture is obtained;

[0053] (2) Diamond micro powder mixture and nickel-based cemented carbide matrix are sequentially loaded into a metal cup to obtain a metal cup assembly;

[0054] (3) The metal cup assembly was sintered for 15 minutes under high temperature and high pressure conditions of 8 GPa and 1650℃ 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 of 510,000 and a coercivity of 0 Oe. Compared with the comparative example, the magnetism of this embodiment is significantly reduced, thus achieving non-magnetization of the polycrystalline diamond composite sheet.

[0056] Example 2

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

[0058] (1) After thoroughly mixing diamond micro powder and nickel powder of different particle sizes, a diamond micro powder mixture is obtained;

[0059] (2) Diamond micro powder mixture and nickel-based cemented carbide matrix are sequentially loaded into a metal cup to obtain a metal cup assembly;

[0060] (3) The metal cup assembly was sintered for 20 minutes under high temperature and high pressure conditions of 7 GPa and 1600℃ to obtain a non-magnetic polycrystalline diamond composite sheet.

[0061] The polycrystalline diamond composite sheet in this embodiment has a grinding wheel wear ratio of 390,000 and a coercivity of 0 Oe. Compared to the comparative example, the magnetism of this embodiment is significantly reduced, achieving demagnetization of the polycrystalline diamond composite sheet.

[0062] In summary, this invention provides a non-magnetic polycrystalline diamond composite sheet, its preparation method, and its application. The non-magnetic polycrystalline diamond composite sheet comprises a nickel-based cemented carbide matrix and a polycrystalline diamond layer composited on the nickel-based cemented carbide matrix; wherein the nickel-based cemented carbide matrix comprises nickel and tungsten carbide, and the polycrystalline diamond layer comprises nickel and diamond micropowder. The non-magnetic polycrystalline diamond composite sheet of this invention uses a nickel-based cemented carbide matrix and nickel as the binder phase of the polycrystalline diamond layer, effectively reducing the magnetism of the polycrystalline diamond composite sheet, and exhibiting high wear resistance and non-magnetic properties, thus meeting 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 examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A non-magnetic polycrystalline diamond composite sheet, characterized in that, It includes a nickel-based cemented carbide matrix and a polycrystalline diamond layer composited on the nickel-based cemented carbide matrix; The nickel-based cemented carbide matrix is ​​composed of nickel and tungsten carbide, and the polycrystalline diamond layer is composed of nickel and diamond powder. 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%. In the polycrystalline diamond layer, the mass percentage of nickel is 1-10%, and the mass percentage of diamond micropowder is 90-99%. The coercivity of the nickel-based cemented carbide matrix is ​​0~25Oe.

2. The non-magnetic polycrystalline diamond composite sheet according to claim 1, characterized in that, The average particle size of the diamond micro powder is 1~100 micrometers.

3. A method for preparing a non-magnetic polycrystalline diamond composite sheet as described in any one of claims 1 to 2, characterized in that, Including the following steps: Diamond micro powders of different particle sizes are mixed evenly to obtain a mixture; or, diamond micro powders of different particle sizes and a binder are mixed evenly to obtain a mixture. The mixture and nickel-based cemented carbide matrix are loaded into a mold and sintered to obtain the non-magnetic polycrystalline diamond composite sheet. The binder is nickel or nickel oxide.

4. The preparation method according to claim 3, characterized in that, In the mixture, the diamond micro powder accounts for 85-100% by mass, and the binder accounts for 0-15% by mass. And / or, the average particle size of the adhesive is 0.1 to 10 micrometers.

5. The preparation method according to claim 3, characterized in that, The mold is a metal cup.

6. The preparation method according to claim 5, characterized in that, The metal cup is made of niobium, zirconium, molybdenum or tantalum.

7. The preparation method according to claim 3, characterized in that, The sintering conditions include: a synthesis pressure of 5-10 GPa, a temperature of 1400-2000℃, and a time of 2-60 min.

8. The application of a non-magnetic polycrystalline diamond composite sheet as described in any one of claims 1 to 2 or a non-magnetic polycrystalline diamond composite sheet prepared by the preparation method as described in any one of claims 3 to 7 in the preparation of bearings.