Composite metal powder, method for its production and use

Abstract

This invention provides a composite metal powder, its preparation method, and its applications. The composite metal powder comprises metal particles and one or more metal wires bonded to the metal particles. The diameter of the metal particles is smaller than the length of the metal wires but larger than the diameter of the metal wires. The composite metal powder of this invention has a spiky, spherical structure with low loose and tap density. When made into powder metallurgy products, it can significantly improve porosity and reduce shrinkage while effectively ensuring the thermal conductivity and mechanical properties of the powder metallurgy products. It also makes the pore size distribution in the powder metallurgy products more uniform and controllable. It is particularly suitable for preparing capillary structures with high reliability, high permeability, and large capillary pull, and has broad application prospects in fields such as heat dissipation devices.

Description

Technical Field

[0001] This invention relates to a metal powder material, specifically to a composite metal powder for powder metallurgy, its preparation method and application, belonging to the field of metal materials technology. Background Technology

[0002] Powder metallurgy is a process technology that uses metal powders (or mixtures of metal and non-metal powders) as raw materials, followed by forming and sintering, to manufacture metallic materials, composite materials, and various types of products. Powder metallurgy can produce porous, semi-dense, or fully dense materials. Among these, porous powder metallurgy materials, with their interconnected, crisscrossing pores, have been widely used in fluid filtration, electrochemistry, fire protection, antifreeze, and thermal management. Research shows that the material, particle size, and shape of the original powder have a crucial influence on the structure of porous powder metallurgy materials. Ideally, for a given original powder with a specific shape, if all its shape characteristics are identical, its maximum porosity is difficult to further increase after loose-pack sintering. To address this issue, the industry has researched various solutions. For example, one common approach is to mix the original powder with a pore-forming agent and sinter it in order to effectively control the porosity and pore size of the sintered body. However, this approach increases material costs and requires an additional step to remove the pore-forming agent during the sintering process, which leads to increased energy consumption. Moreover, the pore-forming agent is often difficult to completely remove from the sintered body, thus negatively affecting the thermal conductivity and strength of the sintered body. Summary of the Invention

[0003] The main objective of this invention is to provide a composite metal powder, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0004] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0005] One aspect of the present invention provides a composite metal powder comprising metal particles and one or more metal wires bonded to the metal particles, wherein the diameter of the metal particles is smaller than the length of the metal wires but larger than the diameter of the metal wires.

[0006] Another aspect of the present invention provides a method for preparing the composite metal powder, comprising: cutting metal fibers into metal wires of a predetermined length;

[0007] The metal wire and metal particles are dispersed in a liquid medium and a binder is added and mixed thoroughly to obtain a liquid phase mixture system;

[0008] A solid mixture containing metal filaments and metal particles is separated from a liquid-phase mixture system and then subjected to drying, heat treatment and crushing processes in sequence to obtain composite metal powder.

[0009] Another aspect of the invention provides a porous structure formed by sintering the aforementioned composite metal powder.

[0010] Another aspect of the invention provides the use of the composite metal powder, for example, in the preparation of heat pipes, heat spreaders or other powder metallurgy products.

[0011] Compared to existing technologies, this invention combines metal particles with metal rods / wires / pillars and other wire-like metal bodies to form a composite metal powder with a spiky structure. This significantly reduces the loose density and tap density. Furthermore, when using this composite metal powder to manufacture powder metallurgy products, it can significantly improve the porosity while effectively ensuring the thermal conductivity and mechanical properties of the powder metallurgy products. It also makes the pore size distribution in the powder metallurgy products more uniform and controllable. In particular, it is suitable for preparing capillary structures with high reliability, high permeability, and large capillary pull, and has broad application prospects in fields such as heat dissipation devices. Attached Figure Description

[0012] Figure 1 This is a schematic cross-sectional view of a composite metal powder according to one embodiment of the present invention;

[0013] Figure 2 This is an electron micrograph of a copper alloy powder in Embodiment 1 of the present invention. Detailed Implementation

[0014] As mentioned above, in view of the shortcomings of the prior art, the inventors, through extensive research and practice, have proposed the technical solution of this invention. Its main purpose is to significantly increase the sintering porosity by introducing metal wires to increase or expand the distance between metal particles. The sintered body of this composite metal powder has very high porosity and possesses strength sufficient for use. The technical solution of this invention will be described in detail below.

[0015] Some embodiments of the present invention provide a composite metal powder comprising metal particles and at least one metal wire bonded to the metal particles, wherein the diameter of the metal particles is smaller than the length of the metal wire but greater than or equal to the diameter of the metal wire.

[0016] In one embodiment, at least one metal wire is attached to different regions of the surface of a metal particle. That is, multiple metal wires may be attached to the surface of a metal particle, and each metal wire is attached to a different position on the surface of the metal particle.

[0017] In one embodiment, a metal wire is bonded to the surface of a metal particle with a localized area between one or both ends.

[0018] In one embodiment, at least two metal wires attached to the surface of a metal particle extend in different directions. For example, the two metal wires attached to the surface of a metal particle may intersect or run parallel to each other in the same plane, or extend in two different planes without intersecting each other, or extend in two different planes but intersect at the intersection of the two planes.

[0019] In one embodiment, the aspect ratio of the metal wire is 3:1 or higher, more preferably 5:1 or higher, to more effectively increase the space between metal particles. Exemplarily, the metal wire has a length of 20 μm-3000 μm and a diameter of 1 μm-100 μm; preferably, the metal wire has a length of 100 μm-1000 μm and a diameter of 5 μm-30 μm. Metal wires of this size can sinter better with the powder, while simultaneously creating vacancies to increase the porosity of the sintered body.

[0020] In one embodiment, the ratio of the length of the metal wire to the diameter of the metal particle is 2:1 or more, preferably 3:1 or more, and more preferably 5:1 or more.

[0021] In one embodiment, the ratio of the diameter of the metal wire to the diameter of the metal particle is preferably 1:1 to 1:10, more preferably 1:2 to 1:8, so as to better achieve sintering and adhesion between the metal wire and the metal particle.

[0022] For example, the particle size of the metal particles is 10μm-6001μm, preferably 10μm-450μm, and more preferably 40μm-350μm. This particle size distribution range can achieve an optimal pore structure.

[0023] In one embodiment, the content of metal wires in the composite metal powder is 50-80 wt%, preferably 60-75 wt%, to significantly reduce the loose density and tap density of the composite metal powder and improve its porosity after sintering.

[0024] In one embodiment, the shape of the metal wire may be straight or curved. Preferably, the metal wire may be a metal wire, a metal rod, or a metal column, but is not limited thereto.

[0025] In one embodiment, the metal particles include regular or irregular particles such as spherical, cubic, frustum-shaped, conical, pyramidal, plate-like, and near-spherical shapes, and are not limited thereto.

[0026] In one embodiment, the metal wire is sintered and bonded to the surface of the metal particles.

[0027] In one embodiment, the metal particles or metal wires may be made of copper, iron, silver, nickel, or alloys thereof, but are not limited thereto.

[0028] In one embodiment, the loose packing density of the composite metal powder is 0.5-1.5 g / cm³. 3 Preferably, it is 0.5-1.3 g / cm³. 3 More preferably 0.5-1.0 g / cm³ 3 A low loose packing density allows the sintered composite metal powder to possess maximum porosity. Furthermore, the tap density of the composite metal powder is preferably 0.5-2.0 g / cm³. 3 .

[0029] For example, please refer to Figure 1 The present invention discloses a composite metal powder formed by sintering quasi-spherical metal particles and multiple metal rods. Each metal rod is bonded to a different position on the surface of the quasi-spherical metal particles, and the extension directions of the multiple metal rods are different. Due to this structure formed by the composite of quasi-spherical metal particles and metal rods, the composite metal powder has abundant pores inside. Furthermore, during the sintering of multiple composite metal powders, the metal rods in adjacent composite metal powders abut against each other, resulting in a significant reduction in the loose density and tap density of the powder formed by the aggregation of these composite metal powders compared to the powder formed by the direct aggregation of the aforementioned quasi-spherical metal particles and the powder formed by the direct aggregation of the aforementioned metal rods. When porous materials are made from multiple composite metal powders using powder metallurgy, the porosity of the porous material can be significantly improved by utilizing the gaps between adjacent composite metal powders and the pores inside each composite metal powder, without the need to add pore-forming agents or increase energy consumption. This results in multi-level pore sizes with uniform and controllable pore sizes at each level. At the same time, the mutual bonding of metal rods in adjacent composite metal powders can effectively reduce the shrinkage rate of the porous material during sintering, ensuring the structural strength of the porous material and improving its reliability. Furthermore, there are no negative impacts caused by pore-forming agent residues, allowing the thermal conductivity, electrical conductivity, and other thermal and electrical properties of the porous material, as well as its surface / internal chemical / physical properties, to be maintained or even improved. This is particularly suitable for preparing capillary structures with high reliability, high permeability, and large capillary pulling force.

[0030] In fact, given that the shape and size of the metal wire and the size of the metal particles are basically determined, even slight changes in the shape of the metal particles will have little impact on the size and shape of the composite metal powder. For example, if... Figure 1 If the spherical metal particles in the composite are replaced with other irregularly shaped metal particles of the same diameter, the size and shape of the final composite metal powder will also be the same. Figure 1The composite metal powder shown is approximate. Furthermore, even if these two composite metal powders are mixed and sintered to form a porous material, the porosity and pore size distribution of the porous material are still well controllable. At the same time, the porous material will still maintain advantages such as high porosity, uniform multi-level pore size distribution, high thermal conductivity, high electrical conductivity, high reliability, and high permeability.

[0031] Furthermore, in this invention, the metal particles can also be regular or irregular polyhedra such as rectangles, cubes, cones, frustums, or other two-dimensional or three-dimensional shapes, and are not limited thereto. The metal wires can also be wavy, zigzag, or arc-shaped, and are not limited thereto.

[0032] Some embodiments of the present invention also provide a method for preparing the composite metal powder, comprising:

[0033] The metal fibers are cut into metal wires of a set length;

[0034] The metal wire and metal particles are dispersed in a liquid medium and a binder is added and mixed thoroughly to obtain a liquid phase mixture system;

[0035] A solid mixture containing metal filaments and metal particles is separated from a liquid-phase mixture system and then subjected to drying, heat treatment and crushing processes in sequence to obtain composite metal powder.

[0036] In one embodiment, the preparation method specifically includes: cutting metal fibers into metal wires and then dispersing them uniformly in a liquid medium to form a metal wire dispersion; then uniformly dispersing the metal particles in the metal wire dispersion; then adding a binder and mixing thoroughly to obtain the liquid phase mixture system.

[0037] In one embodiment, the preparation method specifically includes: separating the solid mixture containing metal filaments and metal particles from the liquid-phase mixture system by pressure filtration.

[0038] In one embodiment, the heat treatment is performed in a protective atmosphere, wherein the heat treatment temperature is 700–900°C. More preferably, the heat treatment time is 30 minutes or more. More preferably, the protective atmosphere includes a hydrogen atmosphere.

[0039] In one embodiment, the liquid-phase mixing system contains 0.5–5 wt% binder. The binder primarily serves to create a slight adhesion between the metal wire and the metal particles, preventing segregation during post-processing drying and material transfer. The binder includes, but is not limited to, a mixed solution with a certain viscosity obtained by dissolving and dispersing vegetable oil, animal oil, mineral oil, plant gum, various gum powders, and / or various thickeners in water and / or alcohols and / or ethers. For example, its viscosity can be 50–50,000 cP and it can completely decompose below 600°C; preferably, its viscosity is 200–8,000 cP and it can decompose below 400°C.

[0040] In a more specific implementation, the metal fibers can be neatly arranged along a specified direction and cut or shortened according to the design length requirements. After cutting, the resulting short metal fibers (i.e., the aforementioned metal wires) can fall directly into a liquid medium with ultrasonic dispersion function. This can avoid the short metal fibers from tangling or electrostatic agglomeration. After dispersing in the liquid medium for at least 30 minutes using an ultrasonic disperser, the metal particles are placed in the dispersion liquid of the short metal fibers and dispersed for at least 30 minutes. Then, after dispersing with the addition of an adhesive for at least 30 minutes, the excess liquid is filtered out by means of squeezing or filtration to obtain a solid mixture of uniformly distributed short metal fibers and metal particles. After further heating and vacuum drying, the solid mixture is then heat-treated for at least 30 minutes under a protective atmosphere of hydrogen and other high-temperature conditions. This heat treatment process mainly aims to sinter the metal short fibers and metal particles together, while removing any remaining binder. The heat-treated mixture is then crushed to obtain composite metal powder. Because the contact area between the metal short fibers and metal particles is large and the sintering strength is high, while the contact between the metal short fibers is relatively loose and the sintering strength is low, the connection between the metal short fibers is broken after low-frequency crushing, but the sintering between the metal short fibers and metal particles is still preserved, forming particles similar to spiky balls.

[0041] Some embodiments of the present invention also provide a composite comprising:

[0042] The aforementioned composite metal powder;

[0043] Adhesive, used to bind the particles of the composite metal powder together.

[0044] Some embodiments of the present invention also provide a granulated powder, which is formed by granulating the composite metal powder.

[0045] Some embodiments of the present invention also provide a sintered body, which is obtained by sintering the composite metal powder.

[0046] Some embodiments of the present invention also provide a porous structure formed by sintering the composite metal powder.

[0047] In one embodiment, the sintering is carried out under vacuum or a protective atmosphere, and the sintering temperature used is 30-100°C lower than the melting point of the metal particles and metal wires with the lower melting point.

[0048] Some embodiments of the present invention also provide a method for preparing a porous structure, comprising: sintering the composite metal powder under vacuum conditions or in a protective atmosphere, wherein the sintering temperature used is 30-100°C lower than the melting point of the metal particles and metal wires with lower melting points.

[0049] In this invention, the sintered body and porous structure can be prepared and characterized by various methods known in the art. For details, please refer to the "Modern Powder Metallurgy Handbook" (2013, Chemical Industry Press) and "Sintered Metal Porous Materials" (edited by Xi Zhengping et al., 2009, Beijing Metallurgical Industry Press).

[0050] Some embodiments of the present invention also provide the use of the composite metal powder or the porous structure in the fabrication of heat dissipation devices.

[0051] Some embodiments of the present invention also provide a heat dissipation device comprising a capillary structure formed by sintering the composite metal powder.

[0052] Furthermore, the heat dissipation device includes heat pipes, vapor chambers, etc., but is not limited to these.

[0053] Obviously, the heat dissipation device may also include a closed housing and a working medium such as water or ethanol encapsulated in the inner cavity of the housing. The capillary structure is disposed in the inner cavity of the housing, but these are common knowledge known to those skilled in the art, and therefore will not be described in detail here.

[0054] The technical solution of the present invention will be described in more detail below with reference to the accompanying drawings and several embodiments. However, it should be understood that the following embodiments are merely for explaining and illustrating the technical solution, and do not limit the scope of the present invention. Furthermore, unless otherwise specified, the various devices and methods used in the following embodiments are known in the art.

[0055] Example 1

[0056] A copper alloy powder, wherein at least a portion of the powder particles consist of spherical Cu particles and a plurality of copper-nickel alloy short wires bonded to the surface of the spherical Cu particles, wherein the spherical Cu particles have a particle size of about 100 micrometers and the copper-nickel alloy short wires have a length of about 500 micrometers and a diameter of about 30 micrometers.

[0057] The copper alloy powder can be prepared by the following method: Multiple long copper-nickel alloy wires (approximately 30 micrometers in diameter, purchased from Xinlide (Tianjin) Welding Materials Co., Ltd., using white copper CuNi10) are arranged in parallel and cut into short copper-nickel alloy wires approximately 500 micrometers in length. These short copper-nickel alloy wires are then directly added to water and ultrasonically dispersed for about 1 hour to form a dispersion of the short copper-nickel alloy wires. Finally, spherical Cu powder (Suzhou Tongbaorui New Materials Co., Ltd., with a particle size of approximately 100 micrometers) is added to the dispersion of the short copper-nickel alloy wires. The mass ratio of copper-nickel alloy short wires to spherical Cu particles was adjusted to approximately 2:1. The mixture was then ultrasonically dispersed for about 1 hour, followed by the addition of methylcellulose and another 30 minutes of ultrasonic dispersion to obtain a liquid-phase mixture containing approximately 1 wt% binder. The solids were then separated from this liquid-phase mixture by extrusion filtration and vacuum dried at 60°C for about 2.5 hours. Subsequently, it was heat-treated at 730°C for about 1 hour under a hydrogen atmosphere, and finally crushed to obtain copper alloy powder. The loose packing density and tap density are shown in Table 1.

[0058] A method for preparing a porous structure using this copper alloy powder includes: placing the copper alloy powder into a mold and compacting it, then sintering it at approximately 980°C for about 1 hour in a hydrogen atmosphere, followed by natural cooling to room temperature, and then demolding to obtain a sintered body with a stable porous structure, the electron microstructure of which is shown below. Figure 2 As shown, the porosity of the sintered body reaches 82%, and it has good hydrophilicity.

[0059] Comparative Example 1

[0060] A method for preparing a porous structure includes: placing spherical Cu powder (same as in Example 1, loose packing density shown in Table 1) into a mold and compacting it, then sintering it at 980°C for about 1 hour in a hydrogen atmosphere, followed by natural cooling to room temperature, and then demolding to obtain a sintered body with a stable porous structure. The porosity of the sintered body is shown in Table 1.

[0061] Comparative Example 2

[0062] A method for preparing a porous structure includes: cutting a long copper-nickel alloy wire into short copper-nickel alloy wires with a length of about 500 micrometers in the same manner as in Example 1, and then uniformly mixing it with spherical copper-nickel alloy powder (the same as in Example 1) at a mass ratio of 2:1 to form a mixed metal powder; then placing the mixed metal powder into a mold and compacting it, and then sintering it at 980°C for about 1 hour in a hydrogen atmosphere, and then naturally cooling it to room temperature, and then demolding it to obtain a sintered body with a porous structure.

[0063] Observation of the sintered body using electron microscopy revealed significant segregation of spherical Cu particles and copper-nickel alloy short lines within its porous structure. Some areas exhibited higher density, dominated by spherical Cu particles, while others showed a high proportion of copper-nickel alloy short lines. The pore distribution was uneven, resulting in poor overall structural stability of the sintered body. Specific test data for this sintered body are shown in Table 1.

[0064] Example 2

[0065] A copper alloy powder, wherein at least a portion of the powder particles consist of an irregular copper-nickel alloy particle and a plurality of short copper wires bonded to the surface of the copper-nickel alloy particle, the copper-nickel alloy particle having a particle size of about 70 micrometers, and the short copper wires having a length of about 300 micrometers and a diameter of about 30 micrometers.

[0066] The copper alloy powder can be prepared by the following method: Multiple short copper wires (approximately 30 micrometers in diameter, purchased from China Aluminum Luoyang Copper Co., Ltd.) are arranged in parallel and cut into copper wires approximately 300 micrometers in length. The obtained copper wires are then directly added to a solvent formed by mixing ethanol and water in a 2:1 mass ratio and ultrasonically dispersed for about 45 minutes to form a dispersion of the copper wires. Then, irregular copper-nickel alloy particles (Suzhou Tongbaorui New Materials Co., Ltd., with a particle size of approximately 70 micrometers) are added to the copper wire dispersion, allowing the copper wires to mix with the alloy. The mass ratio of copper-nickel alloy particles was approximately 1.5:1. The mixture was ultrasonically dispersed for approximately 45 minutes, followed by the addition of polyvinylpyrrolidone and another 45 minutes of ultrasonic dispersion, resulting in a liquid-phase mixture containing approximately 0.8 wt% binder. The solids were then separated from this liquid-phase mixture by extrusion filtration and vacuum-dried at 80°C for approximately 1.5 hours. Subsequently, it was heat-treated at approximately 780°C for approximately 1.5 hours under a hydrogen atmosphere, and finally crushed to obtain copper alloy powder. The loose packing density and tap density are shown in Table 1.

[0067] A method for preparing a porous structure using the copper alloy powder includes: placing the copper alloy powder into a mold and vibrating it, then sintering it at about 980°C for about 1 hour in a hydrogen atmosphere, then naturally cooling it to room temperature, and then demolding it to obtain a sintered body with a stable porous structure. The test data of the sintered body are shown in Table 1.

[0068] Example 3

[0069] A composite copper powder, wherein at least a portion of the powder particles consist of an irregular copper particle and a plurality of short copper wires bonded to the surface of the copper particle, the copper particle having a diameter of about 300 micrometers and the short copper wires having a length of about 800 micrometers and a diameter of about 30 micrometers.

[0070] The composite copper powder can be prepared by the following method: multiple short copper wires (approximately 30 micrometers in diameter, purchased from China Aluminum Luoyang Copper Co., Ltd.) are arranged in parallel and cut into copper wires with a length of approximately 800 micrometers. The obtained copper wires are directly added to ethanol and ultrasonically dispersed for about 1 hour to form a dispersion of copper wires. Then, irregular copper particles (Suzhou Tongbaorui New Materials Co., Ltd., with a particle size of approximately 300 micrometers) are added to the dispersion of copper wires, making the mass ratio of copper wires to irregular copper particles approximately 3:1. Ultrasonic dispersion is continued for about 1 hour, followed by the addition of mineral oil and ultrasonic dispersion for another 1 hour to obtain a liquid-phase mixture containing approximately 5 wt% binder. The solids are then separated from the liquid-phase mixture by extrusion filtration and vacuum dried at approximately 80°C for about 2 hours. Subsequently, the mixture is heat-treated at approximately 900°C for about 1.5 hours under a hydrogen atmosphere and finally crushed to obtain the composite copper powder. The loose density and tap density are shown in Table 1.

[0071] A method for preparing a porous structure using the copper alloy powder includes: placing the copper alloy powder into a mold and vibrating it, then sintering it at about 980°C for about 1 hour in a hydrogen atmosphere, then naturally cooling it to room temperature, and then demolding it to obtain a sintered body with a stable porous structure. The test data of the sintered body are shown in Table 1.

[0072] The composite metal powder of this invention has a spiky spherical structure with low loose density and tap density. When it is made into powder metallurgy products, it can significantly improve the porosity and reduce the shrinkage rate while effectively ensuring the thermal conductivity and mechanical properties of the powder metallurgy products. It also makes the pore size distribution in the powder metallurgy products more uniform and controllable. It is particularly suitable for preparing capillary structures with high reliability, high permeability and large capillary pulling force, and has broad application prospects in the field of heat dissipation devices.

[0073] Although the invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the invention, and that substantially equivalent substances or elements of the embodiments can be substituted. Furthermore, many modifications can be made without departing from the scope of the invention to adapt particular situations or materials to the teachings of the invention. Therefore, this document is not intended to limit the invention to the specific embodiments disclosed for carrying out the invention, but rather to include all embodiments falling within the scope of the appended claims. Table 1 shows the performance test data of the metal powders and their sintered bodies in Examples 1-3 and Comparative Examples 1-2.

[0074]

Claims

1. A composite metal powder, characterized in that, A composite metal powder comprising metal particles and at least one metal linear body sinter-bonded to the surface of the metal particles, the diameter of the metal particles being smaller than the length of the metal linear body but greater than or equal to the diameter of the metal linear body, wherein different regions of the surface of one metal particle each have at least one metal linear body bonded thereto, and at least two metal linear bodies bonded to the surface of one metal particle extend in different directions; the loose bulk density of the composite metal powder being 0.5 to 1.5 g / cm 3 ; Furthermore, the method for preparing the composite metal powder includes: The metal fibers are cut into metal wires of a set length; The metal wire and metal particles are dispersed in a liquid medium and a binder is added and mixed thoroughly to obtain a liquid phase mixture system; A solid mixture containing metal wires and metal particles is separated from a liquid-phase mixture system and then subjected to drying, heat treatment and crushing processes in sequence to obtain composite metal powder. The heat treatment is carried out in a protective atmosphere, with a heat treatment temperature of 700–900°C and a heat treatment time of more than 30 minutes.

2. The composite metal powder according to claim 1, characterized in that: A metal wire is bonded to the surface of a metal particle by a localized area between one or both ends.

3. The composite metal powder according to claim 1, characterized in that: The aspect ratio of the metal wire is greater than 3:

1.

4. The composite metal powder according to claim 3, characterized in that: The aspect ratio of the metal wire is greater than 5:

1.

5. The composite metal powder according to claim 1, characterized in that: The ratio of the length of the metal wire to the diameter of the metal particle is greater than 2:

1.

6. The composite metal powder according to claim 5, characterized in that: The ratio of the length of the metal wire to the diameter of the metal particle is greater than 3:

1.

7. The composite metal powder according to claim 6, characterized in that: The ratio of the length of the metal wire to the diameter of the metal particle is greater than 5:

1.

8. The composite metal powder according to claim 1, characterized in that: The ratio of the diameter of the metal wire to the diameter of the metal particle is 1:1 to 1:

10.

9. The composite metal powder according to claim 8, characterized in that: The ratio of the diameter of the metal wire to the diameter of the metal particle is 1:2 to 1:

8.

10. The composite metal powder according to any one of claims 1-9, characterized in that: The particle size of the metal particles is 10µm-600µm.

11. The composite metal powder according to claim 10, characterized in that: The particle size of the metal particles is 10µm-450µm.

12. The composite metal powder according to claim 11, characterized in that: The particle size of the metal particles is 40µm-350µm.

13. The composite metal powder according to any one of claims 1-9, characterized in that: The length of the metal wire is 20µm-3000µm and the diameter is 1µm-100µm.

14. The composite metal powder according to claim 13, characterized in that: The length of the metal wire is 40µm-2000µm and the diameter is 1µm-40µm.

15. The composite metal powder according to claim 14, characterized in that: The metal wire has a length of 100µm-1000µm and a diameter of 5µm-30µm.

16. The composite metal powder according to claim 1, characterized in that: The shape of the metal wire includes a straight line or a curve.

17. The composite metal powder according to claim 16, characterized in that: The metal wire includes a metal wire, a metal rod, or a metal column.

18. The composite metal powder according to claim 1, characterized in that: The metal particles include spherical particles or irregular particles.

19. The composite metal powder according to claim 1, characterized in that: The composite metal powder contains 50-80 wt% metal wires.

20. The composite metal powder according to claim 19, characterized in that: The composite metal powder contains 60-75 wt% metal wires.

21. The composite metal powder according to claim 1, characterized in that: The materials of the metal particles and metal wires include copper, iron, silver, nickel, or their alloys.

22. The composite metal powder according to claim 1, characterized in that: The loose packing density of the composite metal powder is 0.5-1.3 g / cm³. 3 .

23. The composite metal powder according to claim 22, characterized in that: The loose packing density of the composite metal powder is 0.5-1.0 g / cm³. 3 .

24. The composite metal powder according to claim 21, characterized in that: The tap density of the composite metal powder is 0.5-2.0 g / cm³. 3 .

25. The composite metal powder according to claim 1, characterized in that, The preparation method specifically includes: cutting metal fibers into metal wires and then dispersing them uniformly in a liquid medium to form a metal wire dispersion; then uniformly dispersing the metal particles in the metal wire dispersion; then adding a binder and mixing thoroughly to obtain the liquid phase mixture system.

26. The composite metal powder according to claim 1, characterized in that, The preparation method specifically includes: separating the solid mixture containing metal filaments and metal particles from the liquid-phase mixture system by pressure filtration.

27. The composite metal powder according to claim 1, characterized in that: The protective atmosphere includes a hydrogen atmosphere.

28. The composite metal powder according to claim 25, characterized in that: The liquid phase mixing system contains 0.5 to 5 wt% binder.

29. A complex, characterized in that, Include: The composite metal powder according to any one of claims 1-28; Adhesive, used to bind the particles of the composite metal powder together.

30. A granulated powder, characterized in that: The granulated powder is obtained by granulating the composite metal powder according to any one of claims 1-28.

31. A sintered body, characterized in that: The sintered body is obtained by sintering the composite metal powder according to any one of claims 1-28; the sintering is carried out under vacuum conditions or a protective atmosphere, and the sintering temperature is 30-100°C lower than the melting point of the metal particles and metal wires with lower melting points.

32. The sintered body according to claim 31, characterized in that: The sintered body has a porous structure.

33. Use of the composite metal powder according to any one of claims 1-28 or the sintered body according to any one of claims 31-32 in the preparation of heat dissipation devices.

34. A heat dissipation device, characterized in that... It includes capillary structures formed by sintering the composite metal powder as described in any one of claims 1-28.

Images