Graphene and boron nitride composite material and preparation method thereof

Abstract

The invention relates to a graphene and boron nitride composite material and a preparation method thereof.The preparation method comprises the steps that powder composition is optimized, and plasma ball milling pretreatment and precise reduction drying treatment are adopted; the problems that in the prior art, a graphene / hexagonal boron nitride composite structure is tedious in preparation process, poor in interfacial compatibility, low in structural controllability, difficult to prepare on a large scale and the like are effectively solved, and the finally obtained graphene and boron nitride composite material is remarkably and synergistically improved in the aspects of conductivity, hardness and average friction coefficient; the high-performance copper-based composite wear-resistant conductive material has excellent conductivity, wear resistance and mechanical strength, the preparation process is simple and controllable, large-scale production can be achieved, the application requirement of the industrial field for the high-performance copper-based composite wear-resistant conductive material is met, and the high-performance copper-based composite wear-resistant conductive material has important engineering application value.

Description

Technical Field

[0001] This invention belongs to the field of materials technology, and relates to a metal-based composite material, particularly a graphene-boron nitride composite material and its preparation method. Background Technology

[0002] In industrial production and equipment operation, contact friction and wear between metal components are common and critical issues. Wear, as one of the most significant failure modes of metallic materials, directly restricts production efficiency, equipment reliability, and service life. Especially under conditions of lubricant scarcity or dry friction, the wear rate increases dramatically, significantly raising the risk of failure. Therefore, developing novel metallic materials with excellent dry friction and wear resistance is of significant engineering value for improving the service performance of industrial equipment and reducing energy consumption and maintenance costs.

[0003] Hexagonal boron nitride (h-BN) possesses a graphene-like layered crystal structure and exhibits excellent electrical insulation, chemical stability, and high-temperature resistance, demonstrating great application potential in fields such as thermal management of electronic devices, high-temperature structural ceramics, and wear-resistant protection. However, existing methods for preparing graphene / h-BN heterojunctions or composite structures (such as layer-to-layer transfer and stepwise chemical vapor deposition) generally suffer from problems such as complex process flows, poor controllability of heterojunction morphology and size, low interlayer interface bonding strength, high defect density, and difficulty in achieving large-area uniform preparation. In particular, the in-situ construction of graphene-h-BN composite structures on copper substrates and the achievement of synergistic interface enhancement among the copper substrate, graphene, and h-BN still faces technical bottlenecks such as complex interface control mechanisms, insufficient structural precision, and the difficulty in simultaneously achieving high thermal conductivity and high mechanical / tribological properties.

[0004] Therefore, developing a graphene-boron nitride composite material and its preparation method that can efficiently integrate the performance advantages of copper, graphene, and hexagonal boron nitride, while solving problems such as poor interfacial compatibility, low structural controllability, and difficulties in large-scale preparation, is of great significance for promoting the application and development of graphene-boron nitride composite materials in the fields of wear resistance, thermal conductivity, and multifunctional integration. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a graphene boron nitride composite material and its preparation method. The graphene boron nitride composite material obtained by this preparation method exhibits significant synergistic improvements in electrical conductivity, hardness, and average coefficient of friction, and possesses excellent electrical conductivity, wear resistance, and mechanical strength. The preparation process is simple and controllable, enabling large-scale production, and is well-suited to the application needs of high-performance copper-based composite wear-resistant conductive materials in industrial fields, thus possessing significant engineering application value.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a method for preparing a graphene-boron nitride composite material, the method comprising the following steps:

[0008] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0009] (2) Mix the organic solvent and the powder to obtain a mixture;

[0010] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0011] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0012] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material.

[0013] This invention improves the compatibility and dispersibility of hexagonal boron nitride (BON) through plasma ball milling. Specifically, it uses the synergistic effect of plasma and mechanical force to peel off and refine BON, modifying it into a near-spherical structure, and grafting active groups onto the surface of BON. This invention removes organic matter and other impurities from BON through centrifugal washing, further weakening the interlayer van der Waals forces of BON. However, the large specific surface area of ​​pre-dispersed BON makes it easy for the layers to recombine and agglomerate through van der Waals forces. This invention utilizes glucose as a dispersant to assist in the good dispersion of pre-dispersed BON, while also acting as a carbon source to uniformly coat copper powder, enabling in-situ preparation of graphene during reduction drying.

[0014] Therefore, the preparation method provided by this invention effectively solves the problems of cumbersome preparation process, poor interfacial compatibility, low structural controllability, and difficulty in large-scale preparation of graphene / hexagonal boron nitride composite structures in the prior art by optimizing powder composition, adopting plasma ball milling pretreatment, and precise reduction drying treatment. The resulting graphene-boron nitride composite material has significantly improved electrical conductivity, hardness, and average friction coefficient, and has excellent electrical conductivity, wear resistance, and mechanical strength. The preparation process is simple and controllable, and can be mass-produced. It meets the application needs of high-performance copper-based composite wear-resistant conductive materials in the industrial field and has important engineering application value.

[0015] In some embodiments, the grinding media of the plasma ball milling includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball with gradually increasing average particle size.

[0016] In some embodiments, the mass ratio of the zirconium oxide spheres to the hexagonal boron nitride is 10:1 to 20:1.

[0017] In some embodiments, the average particle size of the first zirconia spheres is 1.8 mm to 2.2 mm.

[0018] In some embodiments, the average particle size of the second zirconia spheres is 4.8 mm to 5.2 mm.

[0019] In some embodiments, the average particle size of the third zirconia spheres is 9.5 mm to 10.5 mm.

[0020] In some embodiments, the mass ratio of the first zirconia ball, the second zirconia ball, and the third zirconia ball is (2.5~3.5):(4.5~5.5):2.

[0021] In some embodiments, the plasma ball mill rotates at a speed of 1000 rpm to 1300 rpm.

[0022] In some embodiments, the plasma gas used in the plasma ball mill includes argon.

[0023] In some embodiments, the discharge frequency of the plasma ball mill is 9 kHz to 10 kHz.

[0024] In some embodiments, the washing solution for centrifugal washing includes water.

[0025] In some embodiments, the centrifugal speed during centrifugal washing is 5000 rpm to 6000 rpm.

[0026] In some embodiments, the temperature of the centrifugal washing is 40°C to 60°C.

[0027] In some embodiments, the mass ratio of the organic solvent to the powder is 0.45:1 to 0.55:1.

[0028] In some embodiments, the organic solvent includes anhydrous ethanol.

[0029] In some embodiments, the powder contains 0.2wt% to 0.5wt% glucose, 0.1wt% to 0.5wt% polyvinylpyrrolidone, 0.2wt% to 0.7wt% pre-dispersed nano boron nitride, with the balance being copper powder and unavoidable impurities.

[0030] In some embodiments, the average particle size of the copper powder is 50 μm to 100 μm.

[0031] In some embodiments, the atmosphere for the acoustic resonance treatment is an argon atmosphere and / or a nitrogen atmosphere.

[0032] In some embodiments, the acoustic resonance treatment lasts for 10 to 20 minutes.

[0033] In some embodiments, the acceleration of the acoustic resonance treatment is 70g to 90g.

[0034] In some embodiments, the reduction drying process is carried out in a reducing atmosphere; the reducing atmosphere includes a mixture of hydrogen and nitrogen.

[0035] In some embodiments, the temperature of the reduction drying process is 500°C to 600°C.

[0036] In some embodiments, the reduction drying process takes 1 to 2 hours.

[0037] In some embodiments, the sintering includes a first sintering, a second sintering, a third sintering, and a fourth sintering performed sequentially, wherein hot pressing is performed during the fourth sintering;

[0038] The first sintering temperature is 180℃~220℃, and the time is 28min~32min;

[0039] The second sintering temperature is 560℃~640℃, and the time is 28min~32min;

[0040] The third sintering temperature is 950℃~1000℃, and the time is 28min~32min;

[0041] The fourth sintering temperature is 1030℃~1050℃, the time is 10min~15min, and the pressure is 50MPa~70MPa.

[0042] In a second aspect, the present invention provides a graphene boron nitride composite material, wherein the graphene boron nitride composite material is prepared by the preparation method described in the first aspect.

[0043] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] This invention improves the compatibility and dispersibility of hexagonal boron nitride (BN) through plasma ball milling. Specifically, it uses the synergistic effect of plasma and mechanical force to peel and refine BN, modifying it into a near-spherical structure, and grafting active groups onto the surface of BN. Centrifugal washing removes organic impurities from BN, further weakening the interlayer van der Waals forces. However, the large specific surface area of ​​the pre-dispersed BN makes it easy for the layers to recombine and agglomerate through van der Waals forces. The use of glucose as a dispersant assists in the good dispersion of the pre-dispersed BN, while also serving as a carbon source to uniformly coat copper powder, enabling in-situ preparation of graphene during reduction drying. Therefore, the graphene-boron nitride composite material obtained by the method provided by this invention exhibits significant synergistic improvements in conductivity, hardness, and average coefficient of friction, possessing excellent electrical conductivity, wear resistance, and mechanical strength. The preparation process is simple and controllable, allowing for large-scale production, and is well-suited to the industrial application needs for high-performance copper-based composite wear-resistant conductive materials, demonstrating significant engineering application value. Detailed Implementation

[0046] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0047] The "range" disclosed in this invention can be defined in the form of a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of the specific range. This type of range definition can include or exclude endpoints; any endpoint can be independently included or excluded, and they can be arbitrarily combined, meaning any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for specific parameters, it is understood that ranges of 60~110 and 80~120 are also expected. Furthermore, if minimum range values ​​1 and 2 are listed, and maximum range values ​​3, 4, and 5 are also listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this invention, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0" and "5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is described as an integer ≥2, it is equivalent to listing integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc. For instance, when a parameter is described as an integer selected from "2~10", it is equivalent to listing the integers 2, 3, 4, 5, 6, 7, 8, 9, and 10.

[0048] In this invention, "a combination of at least two" refers to a quantity greater than or equal to two, unless otherwise specified. For example, "any combination of one or at least two" means one or more or more items. It can be understood that when referring to "a combination of at least two," it refers to any suitable combination of multiple items, that is, a combination of "at least two" items carried out in a manner that does not conflict with and enables the implementation of this invention.

[0049] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0050] The term "embodiment" as used in this invention means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment or implementation of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention can be combined with other embodiments.

[0051] Those skilled in the art will understand that the order in which the steps are written in the methods of the various embodiments does not imply a strict execution order. The detailed execution order of each step should be determined by its function and possible internal logic. Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), meaning that step (c) can be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0052] In this invention, open-ended technical features or solutions described using terms such as "comprising" do not exclude additional members beyond those listed unless otherwise specified. They can be considered as providing both closed-ended features or solutions comprised of the listed members and open-ended features or solutions that include additional members beyond the listed members. For example, A includes a1, a2, and a3. Unless otherwise specified, it may also include other members or exclude additional members. This can be considered as providing both technical features or solutions where "A is composed of a1, a2, and a3" or "A is selected from a1, a2, and a3," and technical features or solutions where "A includes not only a1, a2, and a3, but also other members."

[0053] In this invention, unless otherwise specified, the features or solutions corresponding to "and / or" include any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. For example, "A and / or B" represents a group consisting of A, B, and "a combination of A and B". "Containing A and / or B" can mean "containing A, containing B, and containing A and B", or "containing A, containing B, or containing A and B", and can be appropriately understood according to the context.

[0054] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0055] In this invention, "optional" means that something is optional, that is, it refers to either "with" or "without". If there are multiple "optional" options in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, then each "optional" option is independent.

[0056] In a first aspect, the present invention provides a method for preparing a graphene-boron nitride composite material, the method comprising the following steps:

[0057] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0058] (2) Mix the organic solvent and the powder to obtain a mixture;

[0059] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0060] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0061] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material.

[0062] This invention improves the compatibility and dispersibility of hexagonal boron nitride (BON) through plasma ball milling. Specifically, it uses the synergistic effect of plasma and mechanical force to peel off and refine BON, modifying it into a near-spherical structure, and grafting active groups onto the surface of BON. This invention removes organic matter and other impurities from BON through centrifugal washing, further weakening the interlayer van der Waals forces of BON. However, the large specific surface area of ​​pre-dispersed BON makes it easy for the layers to recombine and agglomerate through van der Waals forces. This invention utilizes glucose as a dispersant to assist in the good dispersion of pre-dispersed BON, while also acting as a carbon source to uniformly coat copper powder, enabling in-situ preparation of graphene during reduction drying.

[0063] Therefore, the preparation method provided by this invention effectively solves the problems of cumbersome preparation process, poor interfacial compatibility, low structural controllability, and difficulty in large-scale preparation of graphene / hexagonal boron nitride composite structures in the prior art by optimizing powder composition, adopting plasma ball milling pretreatment, and precise reduction drying treatment. The resulting graphene-boron nitride composite material has significantly improved electrical conductivity, hardness, and average friction coefficient, and has excellent electrical conductivity, wear resistance, and mechanical strength. The preparation process is simple and controllable, and can be mass-produced. It meets the application needs of high-performance copper-based composite wear-resistant conductive materials in the industrial field and has important engineering application value.

[0064] In some embodiments, the grinding media of the plasma ball milling includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball with gradually increasing average particle size.

[0065] In some embodiments, the mass ratio of the zirconia spheres to the hexagonal boron nitride is 10:1 to 20:1, for example, it can be 10:1, 12:1, 15:1, 16:1, 18:1 or 20:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0066] In some embodiments, the average particle size of the first zirconia spheres is 1.8 mm to 2.2 mm, for example, it can be 1.8 mm, 1.9 mm, 2 mm, 2.1 mm or 2.2 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 2 mm.

[0067] In some embodiments, the average particle size of the second zirconia spheres is 4.8 mm to 5.2 mm, for example, it can be 4.8 mm, 4.9 mm, 5 mm, 5.1 mm or 5.2 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 5 mm being the preferred value.

[0068] In some embodiments, the average particle size of the third zirconia spheres is 9.5 mm to 10.5 mm, for example, it can be 9.5 mm, 9.6 mm, 9.8 mm, 10 mm, 10.2 mm, 10.4 mm or 10.5 mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 10 mm being the preferred value.

[0069] In some embodiments, the mass ratio of the first zirconia ball, the second zirconia ball, and the third zirconia ball is (2.5~3.5):(4.5~5.5):2.

[0070] The mass ratio of the first zirconia ball to the third zirconia ball is (2.5~3.5):2, for example, it can be 2.5:2, 2.7:2, 2.8:2, 3:2, 3.2:2, 3.3:2 or 3.5:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 3:2 being the preferred ratio.

[0071] The mass ratio of the second zirconia ball to the third zirconia ball is (4.5~5.5):2, for example, it can be 4.5:2, 4.8:2, 5:2, 5.2:2, 5.4:2 or 5.5:2, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, with 5:2 being the preferred ratio.

[0072] In some embodiments, the rotational speed of the plasma ball mill is 1000 rpm to 1300 rpm, for example, it can be 1000 rpm, 1050 rpm, 1100 rpm, 1150 rpm, 1200 rpm, 1250 rpm or 1300 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0073] In some embodiments, the plasma gas used in the plasma ball mill includes argon.

[0074] In some embodiments, the discharge frequency of the plasma ball mill is 9kHz to 10kHz, for example, 9kHz, 9.5kHz or 10kHz, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0075] In some embodiments, the washing solution for centrifugal washing includes water.

[0076] In some embodiments, the centrifugal speed during centrifugal washing is 5000 rpm to 6000 rpm, for example, it can be 5000 rpm, 5200 rpm, 5400 rpm, 5500 rpm, 5600 rpm, 5800 rpm or 6000 rpm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0077] In some embodiments, the temperature of the centrifugal washing is 40°C to 60°C, for example, 40°C, 45°C, 50°C, 55°C or 60°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0078] Optionally, the centrifugal washing of the present invention is performed in a shear washing apparatus.

[0079] For example, the shearing washing device includes a frame assembly, a filter assembly, and a power unit. The frame assembly is made of 304 mirror stainless steel, while the filter assembly and parts in contact with materials are made of 316L stainless steel. The power unit is electrically started and belt-driven, with a motor power of up to 3kW, an explosion-proof two-stage power supply, and phase, frequency, and voltage options of 3, 50Hz, and 380V respectively, and a rotation speed of 5000rpm~6000rpm. The filter assembly consists of a first filter element and a second filter element. The first filter element is a 316 stainless steel drum, and the second filter element is a porous titanium drum (mesh size can be 500 nanometers). The surface of the first filter element is equipped with shear grooves to enhance the interlayer peeling force of graphite. The second filter element mainly functions as a filter. The outer layer of the shearing washing device is equipped with a jacket for hot water circulation to maintain the temperature of the centrifugal washing process.

[0080] In some embodiments, the mass ratio of the organic solvent to the powder is 0.45:1 to 0.55:1, for example, it can be 0.45:1, 0.48:1, 0.5:1, 0.52:1, 0.54:1 or 0.55:1, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0081] In some embodiments, the organic solvent includes anhydrous ethanol.

[0082] In some embodiments, the powder contains 0.2wt% to 0.5wt% glucose, 0.1wt% to 0.5wt% polyvinylpyrrolidone, 0.2wt% to 0.7wt% pre-dispersed nano boron nitride, with the balance being copper powder and unavoidable impurities.

[0083] The glucose content is 0.2wt% to 0.5wt%, for example, it can be 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0084] The mass percentage of polyvinylpyrrolidone is 0.1wt% to 0.5wt%, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt% or 0.5wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0085] The mass percentage of pre-dispersed nano boron nitride is 0.2wt% to 0.7wt%, for example, it can be 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt% or 0.7wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0086] In some embodiments, the average particle size of the copper powder is 50 μm to 100 μm, for example, it can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm or 100 μm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0087] In some embodiments, the atmosphere for the acoustic resonance treatment is an argon atmosphere and / or a nitrogen atmosphere.

[0088] In some embodiments, the acoustic resonance treatment time is 10 min to 20 min, for example, it can be 10 min, 12 min, 15 min, 16 min, 18 min or 20 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0089] In some embodiments, the acceleration of the acoustic resonance treatment is 70g to 90g, for example, 70g, 75g, 80g, 85g or 90g, but not limited to the listed values. Other unlisted values ​​within the range are also applicable, where g is the acceleration due to gravity.

[0090] In some embodiments, the reduction drying process is carried out in a reducing atmosphere; the reducing atmosphere includes a mixture of hydrogen and nitrogen.

[0091] In some embodiments, the temperature of the reduction drying process is 500°C to 600°C, for example, 500°C, 510°C, 520°C, 540°C, 550°C, 560°C, 580°C or 600°C, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0092] In some embodiments, the reduction drying treatment time is 1h to 2h, for example, it can be 1h, 1.2h, 1.5h, 1.6h, 1.8h or 2h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0093] In some embodiments, the sintering includes a first sintering, a second sintering, a third sintering, and a fourth sintering performed sequentially, wherein hot pressing is performed during the fourth sintering;

[0094] The first sintering temperature is 180℃~220℃ (e.g., it can be 180℃, 190℃, 200℃, 210℃ or 220℃, etc.), and the time is 28min~32min (e.g., it can be 28min, 29min, 30min, 31min or 32min, etc.);

[0095] The second sintering temperature is 560℃~640℃ (e.g., it can be 560℃, 580℃, 600℃, 620℃ or 640℃, etc.), and the time is 28min~32min (e.g., it can be 28min, 29min, 30min, 31min or 32min, etc.);

[0096] The third sintering temperature is 950℃~1000℃ (e.g., it can be 950℃, 960℃, 970℃, 980℃, 990℃ or 1000℃, etc.), and the time is 28min~32min (e.g., it can be 28min, 29min, 30min, 31min or 32min, etc.);

[0097] The fourth sintering temperature is 1030℃~1050℃ (e.g., 1030℃, 1040℃, or 1050℃, etc.), the time is 10min~15min (e.g., 10min, 11min, 12min, 13min, 14min, or 15min, etc.), and the pressure is 50MPa~70MPa (e.g., 50MPa, 55MPa, 60MPa, 65MPa, or 70MPa, etc.).

[0098] As a preferred embodiment of the preparation method provided by the present invention, the preparation method includes the following steps:

[0099] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0100] The ball milling media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 10:1 to 20:1; the average particle size of the first zirconia ball is 1.8 mm to 2.2 mm, the average particle size of the second zirconia ball is 4.8 mm to 5.2 mm, and the average particle size of the third zirconia ball is 9.5 mm to 10.5 mm;

[0101] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is (2.5~3.5):(4.5~5.5):2;

[0102] The plasma ball mill operates at a speed of 1000 rpm to 1300 rpm, uses argon as the plasma gas, and has a discharge frequency of 9 kHz to 10 kHz.

[0103] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5000 rpm to 6000 rpm, and the temperature is 40℃ to 60℃.

[0104] (2) Mix the organic solvent and the powder to obtain a mixture;

[0105] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0106] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.45:1 to 0.55:1.

[0107] In the powder, the mass percentage of glucose is 0.2wt%~0.5wt%, the mass percentage of polyvinylpyrrolidone is 0.1wt%~0.5wt%, the mass percentage of pre-dispersed nano boron nitride is 0.2wt%~0.7wt%, and the balance is copper powder and unavoidable impurities.

[0108] The average particle size of the copper powder is 50μm~100μm;

[0109] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0110] The atmosphere for the acoustic resonance treatment is an argon atmosphere and / or a nitrogen atmosphere.

[0111] The acoustic resonance treatment time is 10 min to 20 min, and the acceleration is 70 g to 90 g.

[0112] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0113] The reduction drying process is carried out at a temperature of 500℃~600℃ for 1h~2h.

[0114] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0115] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing occurring during the fourth sintering. The first sintering temperature is 180℃~220℃, and the time is 28min~32min; the second sintering temperature is 560℃~640℃, and the time is 28min~32min; the third sintering temperature is 950℃~1000℃, and the time is 28min~32min; the fourth sintering temperature is 1030℃~1050℃, the time is 10min~15min, and the pressure is 50MPa~70MPa.

[0116] One embodiment of the present invention provides a graphene boron nitride composite material, which is prepared by the preparation method described in any embodiment.

[0117] Example 1

[0118] This embodiment provides a method for preparing graphene-boron nitride composite material, including the following steps:

[0119] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0120] The grinding media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 10:1; the average particle size of the first zirconia ball is 2 mm, the average particle size of the second zirconia ball is 5 mm, and the average particle size of the third zirconia ball is 10 mm.

[0121] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is 3:5:2;

[0122] The plasma ball mill operates at a speed of 1000 rpm, uses argon as the plasma gas, and has a discharge frequency of 9.5 kHz.

[0123] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5000 rpm, and the temperature is 40℃.

[0124] (2) Mix the organic solvent and the powder to obtain a mixture;

[0125] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0126] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0127] The powder contains 0.2 wt% glucose, 0.1 wt% polyvinylpyrrolidone, and 0.2 wt% pre-dispersed nano boron nitride, with the remainder being copper powder and unavoidable impurities; the average particle size of the copper powder is 50 μm.

[0128] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0129] The acoustic resonance treatment is performed in an argon atmosphere; the acoustic resonance treatment time is 15 minutes, and the acceleration is 80g.

[0130] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0131] The reduction drying process is carried out at a temperature of 500°C for 1 hour.

[0132] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0133] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering is performed at a temperature of 200°C for 30 minutes; the second sintering is performed at a temperature of 600°C for 30 minutes; the third sintering is performed at a temperature of 1000°C for 30 minutes; and the fourth sintering is performed at a temperature of 1050°C for 10 minutes, with a pressure of 50 MPa.

[0134] Example 2

[0135] This embodiment provides a method for preparing graphene-boron nitride composite material, including the following steps:

[0136] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0137] The ball milling media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 20:1; the average particle size of the first zirconia ball is 2 mm, the average particle size of the second zirconia ball is 5 mm, and the average particle size of the third zirconia ball is 10 mm.

[0138] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is 3:5:2;

[0139] The plasma ball mill operates at a speed of 1300 rpm, uses argon as the plasma gas, and has a discharge frequency of 9.5 kHz.

[0140] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5000 rpm, and the temperature is 60℃.

[0141] (2) Mix the organic solvent and the powder to obtain a mixture;

[0142] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0143] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0144] The powder contains 0.5 wt% glucose, 0.5 wt% polyvinylpyrrolidone, and 0.7 wt% pre-dispersed nano boron nitride, with the remainder being copper powder and unavoidable impurities; the average particle size of the copper powder is 100 μm.

[0145] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0146] The acoustic resonance treatment was performed in an argon atmosphere; the acoustic resonance treatment lasted for 10 minutes and the acceleration was 70g.

[0147] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0148] The reduction drying process is carried out at a temperature of 600℃ for 2 hours.

[0149] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0150] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering temperature is 180°C and the time is 32 minutes; the second sintering temperature is 560°C and the time is 32 minutes; the third sintering temperature is 950°C and the time is 32 minutes; and the fourth sintering temperature is 1030°C and the time is 15 minutes, with a pressure of 70 MPa.

[0151] Example 3

[0152] This embodiment provides a method for preparing graphene-boron nitride composite material, including the following steps:

[0153] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0154] The ball milling media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 15:1; the average particle size of the first zirconia ball is 2 mm, the average particle size of the second zirconia ball is 5 mm, and the average particle size of the third zirconia ball is 10 mm.

[0155] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is 3:5:2;

[0156] The plasma ball mill operates at a speed of 1200 rpm, uses argon as the plasma gas, and has a discharge frequency of 9.5 kHz.

[0157] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5500 rpm, and the temperature is 50℃.

[0158] (2) Mix the organic solvent and the powder to obtain a mixture;

[0159] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0160] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0161] The powder contains 0.3 wt% glucose, 0.3 wt% polyvinylpyrrolidone, and 0.3 wt% pre-dispersed nano boron nitride, with the remainder being copper powder and unavoidable impurities; the average particle size of the copper powder is 80 μm.

[0162] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0163] The acoustic resonance treatment was performed in an argon atmosphere; the acoustic resonance treatment lasted for 20 minutes and the acceleration was 90g.

[0164] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0165] The reduction drying process is carried out at a temperature of 550°C for 1.5 hours.

[0166] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0167] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering temperature is 220°C and the time is 28 minutes; the second sintering temperature is 640°C and the time is 28 minutes; the third sintering temperature is 1000°C and the time is 28 minutes; the fourth sintering temperature is 1050°C and the time is 10 minutes, with a pressure of 60 MPa.

[0168] Example 4

[0169] This embodiment provides a method for preparing graphene-boron nitride composite material, including the following steps:

[0170] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0171] The ball milling media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 15:1; the average particle size of the first zirconia ball is 2 mm, the average particle size of the second zirconia ball is 5 mm, and the average particle size of the third zirconia ball is 10 mm.

[0172] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is 3:5:2;

[0173] The plasma ball mill operates at a speed of 1300 rpm, uses argon as the plasma gas, and has a discharge frequency of 9.5 kHz.

[0174] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5500 rpm, and the temperature is 50℃.

[0175] (2) Mix the organic solvent and the powder to obtain a mixture;

[0176] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0177] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0178] The powder contains 0.5 wt% glucose, 0.2 wt% polyvinylpyrrolidone, and 0.3 wt% pre-dispersed nano boron nitride, with the remainder being copper powder and unavoidable impurities; the average particle size of the copper powder is 80 μm.

[0179] (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0180] The acoustic resonance treatment is performed in an argon atmosphere; the acoustic resonance treatment time is 15 minutes, and the acceleration is 80g.

[0181] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0182] The reduction drying process is carried out at a temperature of 560°C for 1.5 hours.

[0183] (4) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0184] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering is performed at a temperature of 200°C for 30 minutes; the second sintering is performed at a temperature of 600°C for 30 minutes; the third sintering is performed at a temperature of 1000°C for 30 minutes; and the fourth sintering is performed at a temperature of 1000°C for 10 minutes, with a pressure of 70 MPa.

[0185] Comparative Example 1

[0186] This comparative example provides a method for preparing a graphene-boron nitride composite material, which is the same as that in Example 1 except that plasma ball milling was not performed, and includes the following steps:

[0187] (1) Mix the organic solvent and the powder to obtain a mixture;

[0188] The powder includes copper powder, glucose, polyvinylpyrrolidone, and boron nitride nanoparticles.

[0189] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0190] The powder contains 0.2 wt% glucose, 0.1 wt% polyvinylpyrrolidone, and 0.2 wt% boron nitride nanoparticles, with the remainder being copper powder and unavoidable impurities; the copper powder has an average particle size of 50 μm.

[0191] (2) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder;

[0192] The acoustic resonance treatment is performed in an argon atmosphere; the acoustic resonance treatment time is 15 minutes, and the acceleration is 80g.

[0193] The reduction drying process is carried out in a reducing atmosphere, and the reducing atmosphere includes a mixture of hydrogen and nitrogen; in the mixture, the volume ratio of hydrogen to nitrogen is 6:4.

[0194] The reduction drying process is carried out at a temperature of 500°C for 1 hour.

[0195] (3) Sinter the reduced powder to obtain the graphene boron nitride composite material;

[0196] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering is performed at a temperature of 200°C for 30 minutes; the second sintering is performed at a temperature of 600°C for 30 minutes; the third sintering is performed at a temperature of 1000°C for 30 minutes; and the fourth sintering is performed at a temperature of 1050°C for 10 minutes, with a pressure of 50 MPa.

[0197] Comparative Example 2

[0198] This comparative example provides a method for preparing a graphene-boron nitride composite material, which is the same as in Example 1 except that the pressure of the fourth sintering is 30 MPa.

[0199] Comparative Example 3

[0200] This comparative example provides a method for preparing a graphene boron nitride composite material. Except for the mass percentage of pre-dispersed nano boron nitride in the powder being 2.4 wt%, all other methods are the same as in Example 1.

[0201] Comparative Example 4

[0202] This comparative example provides a method for preparing a boron nitride composite material, which is the same as that in Example 1 except that the reduction and drying treatment is not performed, and includes the following steps:

[0203] (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride;

[0204] The grinding media of the plasma ball mill includes zirconia balls; the zirconia balls include a first zirconia ball, a second zirconia ball, and a third zirconia ball; the mass ratio of the zirconia balls to the hexagonal boron nitride is 10:1; the average particle size of the first zirconia ball is 2 mm, the average particle size of the second zirconia ball is 5 mm, and the average particle size of the third zirconia ball is 10 mm.

[0205] The mass ratio of the first zirconia sphere, the second zirconia sphere, and the third zirconia sphere is 3:5:2;

[0206] The plasma ball mill operates at a speed of 1000 rpm, uses argon as the plasma gas, and has a discharge frequency of 9.5 kHz.

[0207] The washing liquid used in the centrifugal washing is water, the centrifugation speed is 5000 rpm, and the temperature is 40℃.

[0208] (2) Mix the organic solvent and the powder to obtain a mixture;

[0209] The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride;

[0210] The organic solvent is anhydrous ethanol, and the mass ratio of the organic solvent to the powder is 0.5:1.

[0211] The powder contains 0.2 wt% glucose, 0.1 wt% polyvinylpyrrolidone, and 0.2 wt% pre-dispersed nano boron nitride, with the remainder being copper powder and unavoidable impurities; the average particle size of the copper powder is 50 μm.

[0212] (3) The mixture is subjected to acoustic resonance treatment and sintering to obtain the boron nitride composite material;

[0213] The acoustic resonance treatment is performed in an argon atmosphere; the acoustic resonance treatment time is 15 minutes, and the acceleration is 80g.

[0214] The sintering process includes a first sintering, a second sintering, a third sintering, and a fourth sintering, performed sequentially, with hot pressing performed during the fourth sintering. The first sintering is performed at a temperature of 200°C for 30 minutes; the second sintering is performed at a temperature of 600°C for 30 minutes; the third sintering is performed at a temperature of 1000°C for 30 minutes; and the fourth sintering is performed at a temperature of 1050°C for 10 minutes, with a pressure of 50 MPa.

[0215] Performance Characterization

[0216] The electrical conductivity, hardness, and average coefficient of friction of the materials provided in the above embodiments and comparative examples were tested, and the results are shown in Table 1.

[0217] The conductivity is expressed as a percentage of the International Standard for Annealed Copper (IACS), and the calculation formula is as follows:

[0218] IACS(%) = (1.72 × 10) -8 / Measured volume resistivity) × 100%; where 1.72 × 10 -8 Ω·m is the international standard resistivity of annealed pure copper.

[0219] Hardness was tested using an HB-3000 Brinell hardness tester with a 5mm diameter hardened steel ball indenter, a test load of 750kgf, and a holding time of 30s. Before testing, the upper and lower surfaces of the material were polished.

[0220] The average friction coefficient was tested using an HT-1000 high-temperature friction and wear tester. The wear material was 45 steel (HRC56-75), the friction speed was 300 rpm, the wear time was 30 min, and the load was 5 N.

[0221] Table 1

[0222]

[0223] As can be seen from Examples 1 to 4 in Table 1, the graphene boron nitride composite material provided by the present invention can simultaneously improve electrical conductivity, hardness and wear resistance, and has excellent electrical conductivity, mechanical strength and friction reduction and wear resistance characteristics, which is suitable for the application needs of high-performance copper-based composite wear-resistant conductive materials in the industrial field.

[0224] A comparison of Comparative Example 1 and Example 1 shows that without plasma ball milling modification, the electrical conductivity, mechanical strength, and wear resistance of the composite material cannot be improved simultaneously. This indicates that the synergistic effect of plasma and mechanical force can achieve the exfoliation and refinement of hexagonal boron nitride, modification of its spherical structure, and grafting of surface-active groups, significantly improving its compatibility and dispersibility in the copper matrix. Unmodified hexagonal boron nitride is prone to lamellar agglomeration and stacking, which not only destroys the continuous conductive network of the copper matrix, leading to a decrease in conductivity, but also fails to achieve effective second-phase dispersion strengthening and interfacial lubrication, ultimately causing simultaneous deterioration of hardness and wear resistance.

[0225] A comparison between Comparative Example 2 and Example 1 shows that insufficient hot-pressing pressure during the sintering stage cannot simultaneously guarantee the electrical conductivity, mechanical properties, and wear resistance of the composite material. This indicates that high-pressure hot pressing in the fourth sintering stage is beneficial for achieving sufficient powder densification, and sufficient pressure can effectively eliminate defects such as grain boundary pores. When the pressure is insufficient, the density of the composite material decreases significantly, and the remaining pores not only increase the electrical interface impedance and reduce conductivity, but also weaken the load-bearing capacity of the matrix, leading to a decrease in hardness. Furthermore, they exacerbate abrasive wear during friction, resulting in an increased coefficient of friction and deterioration of wear resistance.

[0226] A comparison of Comparative Example 3 and Example 1 shows that excessive addition of pre-dispersed nano-boron nitride reduces the electrical conductivity, mechanical properties, and wear resistance of the composite material. This indicates that within the preferred low addition range of this invention, hexagonal boron nitride can be uniformly dispersed in the copper matrix, achieving a positive modification effect of dispersion strengthening and synergistic lubrication. When added in excess, the insulating hexagonal boron nitride forms a continuous insulating barrier layer in the matrix, severely damaging the conductive network. At the same time, its huge specific surface area causes the layers to re-agglomerate and stack through van der Waals forces, forming stress concentration defects in the matrix. During friction, the agglomerated boron nitride also becomes hard abrasive particles, exacerbating interfacial scraping, ultimately completely losing the modification effect and significantly reducing all properties.

[0227] A comparison of Comparative Example 4 and Example 1 shows that without reduction drying treatment, the synergistic modification effect of graphene and hexagonal boron nitride on the copper matrix cannot be achieved. This indicates that during the reduction drying process, glucose acts as a dispersant to help the pre-dispersed boron nitride maintain a good dispersion state and avoid secondary agglomeration of the sheets. It also acts as a carbon source to uniformly coat the copper powder surface and prepare graphene in situ. At the same time, the reducing atmosphere can effectively remove the oxide layer on the surface of the copper powder. Without this step, graphene cannot be generated in situ to construct a continuous conductive network and a synergistic lubrication system. The oxide layer on the surface of the copper powder will also increase the interfacial contact resistance. In addition, boron nitride is prone to secondary agglomeration, ultimately resulting in the composite material's conductivity, mechanical properties, and wear resistance not reaching the optimal level.

[0228] In summary, this invention improves the compatibility and dispersibility of hexagonal boron nitride through plasma ball milling. Specifically, it uses the synergistic effect of plasma and mechanical force to peel and refine hexagonal boron nitride, modifying it into a near-spherical structure, and grafting active groups onto the surface of hexagonal boron nitride. This invention removes organic matter and other impurities from hexagonal boron nitride through centrifugal washing, further weakening the interlayer van der Waals forces. However, the large specific surface area of ​​pre-dispersed hexagonal boron nitride makes it easy for the layers to recombine and aggregate through van der Waals forces. This invention utilizes glucose to... Glucose acts as a dispersant to facilitate the good dispersion of pre-dispersed boron nitride. Simultaneously, glucose also serves as a carbon source, uniformly coating copper powder to prepare graphene in situ during the reduction and drying process. Therefore, the graphene-boron nitride composite material obtained by the preparation method provided by this invention exhibits significant synergistic improvements in conductivity, hardness, and average coefficient of friction, possessing excellent electrical conductivity, wear resistance, and mechanical strength. The preparation process is simple and controllable, enabling large-scale production, and is well-suited to the industrial application needs for high-performance copper-based composite wear-resistant conductive materials, thus possessing significant engineering application value.

[0229] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a graphene-boron nitride composite material, characterized in that, The preparation method includes the following steps: (1) Plasma ball milling of hexagonal boron nitride, followed by centrifugal washing, yields pre-dispersed hexagonal boron nitride; (2) Mix the organic solvent and the powder to obtain a mixture; The powder comprises copper powder, glucose, polyvinylpyrrolidone, and the pre-dispersed nano boron nitride; (3) The mixture is subjected to acoustic resonance treatment and reduction drying treatment in sequence to obtain reduced powder; (4) Sinter the reduced powder to obtain the graphene boron nitride composite material.

2. The preparation method according to claim 1, characterized in that, The grinding media for the plasma ball milling include zirconium oxide balls; The zirconia spheres include a first zirconia sphere, a second zirconia sphere, and a third zirconia sphere with gradually increasing average particle size.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the zirconium oxide spheres to the hexagonal boron nitride is 10:1 to 20:1; And / or, the average particle size of the first zirconia spheres is 1.8 mm to 2.2 mm; And / or, the average particle size of the second zirconia spheres is 4.8 mm to 5.2 mm; And / or, the average particle size of the third zirconia spheres is 9.5 mm to 10.5 mm; And / or, the mass ratio of the first zirconia ball, the second zirconia ball and the third zirconia ball is (2.5~3.5):(4.5~5.5):

2.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The rotation speed of the plasma ball mill is 1000 rpm to 1300 rpm; And / or, the plasma gas used in the plasma ball milling includes argon; And / or, the discharge frequency of the plasma ball mill is 9kHz~10kHz.

5. The preparation method according to any one of claims 1 to 4, characterized in that, The washing solution for centrifugal washing includes water; And / or, the centrifugal speed during the centrifugal washing is 5000 rpm to 6000 rpm; And / or, the temperature of the centrifugal washing is 40℃~60℃.

6. The preparation method according to any one of claims 1 to 5, characterized in that, The mass ratio of the organic solvent to the powder is 0.45:1 to 0.55:1; And / or, the organic solvent includes anhydrous ethanol; And / or, in the powder, the mass percentage of glucose is 0.2wt%~0.5wt%, the mass percentage of polyvinylpyrrolidone is 0.1wt%~0.5wt%, the mass percentage of pre-dispersed nano boron nitride is 0.2wt%~0.7wt%, and the balance is copper powder and unavoidable impurities; And / or, the average particle size of the copper powder is 50 μm to 100 μm.

7. The preparation method according to any one of claims 1 to 6, characterized in that, The acoustic resonance treatment is performed in an argon atmosphere and / or a nitrogen atmosphere. And / or, the acoustic resonance treatment time is 10 min to 20 min; And / or, the acceleration of the acoustic resonance treatment is 70g~90g.

8. The preparation method according to any one of claims 1 to 7, characterized in that, The reduction and drying process is carried out in a reducing atmosphere; The reducing atmosphere uses a mixture of hydrogen and nitrogen. And / or, the temperature of the reduction drying treatment is 500℃~600℃; And / or, the reduction drying treatment time is 1h to 2h.

9. The preparation method according to any one of claims 1 to 8, characterized in that, The sintering includes a first sintering, a second sintering, a third sintering and a fourth sintering, which are performed sequentially, and hot pressing is performed during the fourth sintering; The first sintering temperature is 180℃~220℃, and the time is 28min~32min; The second sintering temperature is 560℃~640℃, and the time is 28min~32min; The third sintering temperature is 950℃~1000℃, and the time is 28min~32min; The fourth sintering temperature is 1030℃~1050℃, the time is 10min~15min, and the pressure is 50MPa~70MPa.

10. A graphene-boron nitride composite material, characterized in that, The graphene-boron nitride composite material is prepared by the preparation method according to any one of claims 1 to 9.

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