A readily processable diamond / copper thermal conductive material reinforced with nano-active particles and its preparation method.

Abstract

This invention proposes a readily processable diamond / copper thermal conductive material reinforced with nano-active particles and its preparation method, belonging to the technical field of metal matrix composites. It addresses technical problems such as uneven distribution of multiple materials and loose sample structure in diamond / copper composites. The invention includes the following steps: mixing a mixed powder composed of copper powder, diamond, and nano-reinforcing element powder with an additive solution to obtain a slurry; coating the slurry onto a substrate carrier and heating and drying it to solidify it into a diamond / copper layer; subsequently, coating another layer of copper powder onto the diamond / copper layer to form a preform consisting of a substrate + diamond / copper layer + copper powder layer; sintering the pressed preform using a debinding and sintering process to obtain the diamond / copper thermal conductive material; and grinding and polishing the diamond / copper thermal conductive material. The diamond / copper thermal conductive material prepared by this invention has a dense structure, uniform material distribution, and high manufacturing efficiency, making it suitable for mass production.

Description

Technical Field

[0001] This invention belongs to the technical field of metal matrix composites, and particularly relates to a diamond / copper thermal conductive material reinforced with nano-active particles that is easy to process and its preparation method. Background Technology

[0002] With the rapid development of microelectronics and communication technologies, semiconductor chips are constantly evolving towards higher integration, miniaturization, higher frequency, and higher power. The power density of core devices is increasing dramatically, and operating heat is also rising significantly, placing higher demands on electronic packaging and heat dissipation materials. Diamond, as the substance with the highest thermal conductivity in nature (approximately 1000-2000 W / mK) and a low coefficient of thermal expansion (2.3 x 10⁻⁶), is a suitable material. -6 K -1 Diamond is often combined with Cu to prepare diamond / copper thermal conductive materials. This composite material has the advantages of high thermal conductivity and a thermal expansion coefficient that is consistent with that of the chip. It is a new generation of ultra-high thermal conductivity material and has become one of the research hotspots in the field of electronic packaging and heat dissipation materials.

[0003] Thermal conduction in metallic copper (Cu) is primarily electron-based, with free electrons undergoing violent collisions under heat. Diamond, being a non-metallic crystalline structure, relies mainly on phonon motion for heat conduction. Therefore, diamond / copper composites achieve heat conduction through the combined action of electrons and phonons. Currently, the main factors affecting the thermal conductivity of diamond / copper composites are that diamond and Cu neither wet nor chemically react, and the significant difference in their coefficients of thermal expansion introduces thermal stress and resistance at the interface, significantly impacting the improvement of the composite's thermal conductivity. Current methods primarily rely on matrix alloying and diamond surface metallization to reduce the wetting angle between diamond and copper, improve the interfacial bonding, reduce interfacial thermal resistance, and enhance the thermal conductivity of diamond / copper composites. Existing diamond / copper preparation methods mainly involve gas pressure infiltration, spark plasma sintering, high-temperature high-pressure, and repeated pressure and sintering to produce thick, coarse-grained diamond / copper composites, focusing on improving the performance of diamond / copper thermally conductive materials through material adjustment and sintering process iterations. For example, patent publication number CN 107916356A discloses a method for preparing a diamond / copper composite material with high thermal conductivity, including the following steps: (1) diamond and tungsten powder after surface degreasing and roughening treatment are mixed evenly at a mass ratio of 1:4.5, and the mixed powder is heated under vacuum conditions and kept at 1030℃ for 2-8 hours, wherein the vacuum degree is 10 -2 -10 -4Pa, heating rate 5℃ / min, and finally separated the modified tungsten-plated diamond; (2) the surface-modified tungsten-plated diamond with an average particle size of 125μm was mixed with copper powder with an average particle size of 45μm at a total volume content of 55%, and the resulting mixed powder was sintered. The sintering parameters were: pressing pressure 40MPa, temperature 1000℃, heating rate 100℃ / min, sintering time 10min, and the atmosphere was vacuum. Then it was cooled to room temperature to obtain diamond / copper composite material. However, existing technologies have failed to adequately address the uniformity of multiphase material forming and the feasibility of multi-component material processing. The main problems are: (1) Difficult material forming and low density: Due to the density difference and poor compatibility between inert diamond and reactive copper, multi-component materials are difficult to distribute uniformly during the mixing, forming, and sintering processes using dry mixing. Pores and cracks are easily generated at the diamond / copper interface, resulting in a loose and insufficiently dense sample structure. The increased number of interfacial gaps causes the scattering of electrons and phonons that play a role in heat conduction, leading to an increase in interfacial thermal resistance and a sharp decrease in the thermal conductivity of the composite material; (2) Difficult processing and manufacturing: The high hardness of diamond results in poor machinability of composite materials with diamond particles as the reinforcing phase. The different removal rates of diamond and copper lead to poor surface precision, making traditional machining difficult; (3) High preparation cost: The preparation technology is immature, the manufacturing process is complex, the preparation cost is high, and it is difficult to mass-produce. In summary, it is urgent to develop an efficient, homogeneous, and easily machinable diamond / copper thermal conductive material and its preparation method to address the above problems. Summary of the Invention

[0004] To address the technical problems in existing diamond / copper composite materials, such as uneven distribution of multiple materials, easy formation of pores and cracks at the diamond / copper interface, and loose sample structure, this invention proposes a diamond / copper thermal conductive material reinforced with nano-active particles that is easy to process, and its preparation method. The prepared diamond / copper thermal conductive material has a dense structure, uniform material distribution, and high manufacturing efficiency, making it suitable for mass production.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] A method for preparing an easily machinable diamond / copper thermal conductive material reinforced with nano-active particles mainly includes steps such as mixing, molding, debinding-sintering, and processing.

[0007] The mixing step refers to preparing a slurry by mixing copper powder, diamond, nano-reinforcing element powder, and additive solution. The copper powder is electrolytic copper powder with a size of 15-150 μm, the diamond has a particle size of 50-250 μm, and the nano-reinforcing element powder includes copper powder, Ti powder, B powder, Co powder, Cr powder, etc., with a size of 2-500 nm. The mass percentage of each component in the mixed powder is as follows: diamond content is 20%-55%, nano-reinforcing element powder content is 0.5%-5%, and the remainder is copper powder. The additive solution includes solvent, binder, plasticizer, etc. The amount of solvent is 10-30% of the mass of the mixed powder; the amount of additive is 2-10% of the mass of the mixed powder, of which plasticizer accounts for 30-70% of the additive mass, and the remainder is binder. The solvent can be a single-component or multi-component solvent, mainly including ethanol, toluene, acetone, deionized water, etc. The binder is any one or a combination of polyethylene glycol, polyvinyl alcohol, polyvinyl chloride, polymethyl methacrylate, polyvinyl butyral, sodium alginate, dextrin, gelatin, seaweed gum, carboxymethyl cellulose, or starch phosphate. The plasticizer is polyethylene glycol, dioctyl phthalate, dibutyl phthalate, polyvinyl alcohol, polyvinyl acetate, etc. The mixing method includes hot melt mixing, ball milling mixing, ultrasonic stirring mixing, and resonant acoustic mixing.

[0008] The novel molding process is roll coating, which involves coating followed by film rolling. The coating process involves a uniformly mixed slurry being transferred onto a substrate carrier by adjusting the amount of mixture transferred between the coating rollers or doctor blades. The solvent in the slurry spread on the substrate is removed by drying and heating, allowing the diamond / copper mixture to adhere well to the substrate, forming a diamond / copper layer. Subsequently, a layer of copper powder is coated onto the diamond / copper layer, forming a preform consisting of a substrate, a diamond / copper layer, and a copper powder layer. The copper powder in the copper powder layer has a particle size of 10-100 μm and a thickness of 0.2-100 mm. The carrier material is a thin film material such as copper film, copper foil, or copper mesh. The drying process can be performed in situ during the roll coating process, with the drying temperature set between 25-65℃. Next, the diamond / copper preform is kept flat and passed through high-precision rollers under pressure to obtain a high-density and tightly bonded composite material. Finally, after stress relief by a non-powered roller, it is cut to obtain the required shape and size of the thermally conductive material. Cutting methods include laser cutting, punching, and die cutting. A scraper spiral micrometer and a high-precision thickness gauge are installed above the scraper to detect and control the thickness of the diamond / copper thermally conductive material.

[0009] The degreasing-sintering process includes one-step degreasing sintering and multi-step degreasing sintering. This involves placing the aforementioned diamond / copper thermal conductive material preform in a graphite mold coated with BN release agent, and using sintering equipment such as vacuum hot pressing sintering or spark plasma sintering. At an initial pressure below 2 MPa, the temperature is raised to 300-400°C at a rate of 5-10°C / min, held for 5-15 minutes to remove a small amount of binder. Subsequently, the temperature is raised to 900-1000°C at a rate of 8-15°C / min, and the pressure is increased to 50-80 MPa. This is held for 15-20 minutes, and finally, the furnace is cooled to 300°C to release the gas and vacuum. After cooling to room temperature, the mold is removed to obtain a highly dense diamond / copper thermal conductive material with an easily machinable surface.

[0010] The machining process includes grinding and polishing. The grinding and polishing process involves grinding the pure copper layer on the upper and lower surfaces of the sintered diamond / copper thermal conductive material with a grinding disc or grinding wheel, followed by mechanical polishing or electrochemical polishing to obtain a bright surface, thus preparing a diamond / copper thermal conductive material with low surface roughness and high precision.

[0011] The beneficial effects of this invention are:

[0012] (1) This invention introduces nano-reinforcing element powder into diamond / copper thermal conductive materials to obtain high thermal conductivity. From a molding perspective, the nano-reinforcing element powder can fill the gaps between diamond and large-particle electrolytic copper powder, improving defects such as looseness and porosity in the composite material structure, allowing diamond and copper powder to form a strong mechanical bond, thereby improving the material's thermal conductivity. From a sintering perspective, compared with conventional powders, the nano-reinforcing element powder has high surface energy and high activity. The high interfacial energy during sintering becomes the driving force for atomic motion, which is beneficial for atomic diffusion near the interface. Under the same conditions, the diamond / copper thermal conductive material with nano-reinforcing element powder has high interfacial bonding strength and excellent thermal conductivity. Some nano-carbide-generating elements readily react chemically with the diamond surface during sintering to generate carbides, reducing the wetting angle between diamond and copper and improving the interfacial bonding strength between them. For example, elements Ti and Cr react chemically with the diamond surface during sintering to generate carbides such as TiC and Cr3C2. Some types of nano-reinforcing elements can form copper alloys through diffusion solid solution during sintering, thereby achieving matrix alloying, improving interfacial bonding, and increasing the thermal conductivity of diamond / copper matrix composites. For example, element B can react with copper to form Cu-B alloys.

[0013] (2) This invention avoids problems such as density segregation, diamond particle agglomeration, and uneven distribution of the two components caused by direct molding of powder due to the difference in properties of diamond particles and copper powder through wet mixing technology, and provides a uniform front-end composition for diamond / copper thermal conductive materials.

[0014] (3) The present invention can achieve near-net-shape forming of complex diamond / copper through a novel forming method. At the same time, the novel forming method forms a dense composite structure of copper + diamond / copper + copper. After sintering, only grinding and polishing of the pure copper layer surface is required to obtain high-quality diamond / copper thermal conductive material, which solves the problems of difficult surface processing and low efficiency of diamond / copper thermal conductive material.

[0015] (4) The present invention uses a highly mechanized and intelligent production method to manufacture diamond / copper thermal conductive materials, which improves production efficiency and is suitable for mass production. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A schematic diagram of the preparation of diamond / copper thermal conductive material in Example 1; (a) after degreasing and sintering, (b) after machining.

[0018] Figure 2 Internal microstructure diagram of the diamond / copper thermal conductive material prepared in Example 1. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1

[0021] A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles includes the following steps:

[0022] (1) Mixing: The diamond / copper thermal conductive material powder used is composed of: 35wt.% diamond with a particle size of 100-120μm, 1wt.% titanium powder with a particle size of 500nm, and the balance being electrolytic copper powder with an average size of 50μm (metal powder purity ≥99.9%). The above powders are weighed, mixed evenly, sieved, and set aside for later use. The additive solution is introduced into a mixing tank containing the mixed powder, and mixed for 8 minutes under a 45G load using a resonant acoustic mixer. After standing for 3 minutes, a mixed slurry with a certain viscosity is obtained. The mass of the additives in the additive solution is 3% of the raw material of the composite material. The additives include polyvinyl alcohol and polyethylene glycol, with polyethylene glycol accounting for 60wt.% and polyvinyl alcohol accounting for 40wt.%. The solvent is anhydrous ethanol, and the mass of the solvent is 25% of the mass of the composite material powder.

[0023] (2) Molding: The above-mentioned mixed paste is injected into the material tank of a high-precision roller coater, and the slurry is transferred to the copper foil carrier by the rotation of the coating roller. The scraper movement speed is set to 100 mm / min and the scraper gap is 2.5 mm, thus obtaining pure copper + diamond / copper material. The drying temperature is set to 50℃ to remove the solvent in the slurry spread on the substrate, so that the diamond / copper adheres well to the copper foil. The above operation is repeated with a pure copper powder tank and the scraper gap is set to 3.0 mm. A layer of copper powder with a particle size of 50 μm is then coated on the surface of the diamond / copper material to form a three-layer structure of pure copper + diamond / copper + pure copper. Then, a high-precision roller is used to obtain a high density and tightly bonded composite material under pressure. Finally, the stress is released by a non-powered roller. The diamond / copper thermal conductive material preform is laid flat on the laser slitting platform, and the appropriate laser focal length is adjusted to cut a circular diamond / copper thermal conductive material preform with an outer diameter of 30 mm.

[0024] (3) Debinding and Sintering: The above-mentioned diamond / copper thermal conductive material preform was placed in a graphite mold sprayed with BN release agent. Using a spark plasma sintering device, the temperature was raised to 340℃ at an initial pressure of 2MPa and a heating rate of 10℃ / min, held for 15min to debind and remove a small amount of binder. Then, the pressure was raised to 60MPa and the temperature was raised to 950℃ at a heating rate of 15℃ / min, held for 20min, and finally cooled to 300℃ in the furnace to release the gas and vacuum. After cooling to room temperature, the mold was removed to obtain a highly dense diamond / copper thermal conductive material. The sintered sample is shown below. Figure 1 As shown in (a);

[0025] (4) Machining: The pure copper layers on the upper and lower surfaces of the sintered diamond / copper thermal conductive material are ground with a white corundum grinding wheel, then resin-mounted and mechanically polished to obtain a bright surface, thus preparing a diamond / copper thermal conductive material with low surface roughness and high precision. The ground sample is shown in the figure. Figure 1As shown in (b). Figure 2 This is a diagram of the internal structure of a diamond / copper thermal conductive material. Figure 2 The phenomenon of copper matrix climbing on diamond surface indicates that diamond copper with nanoparticles has high bonding strength at the interface, which improves the wettability of diamond and copper. Therefore, the composite material has excellent thermal conductivity.

[0026] Example 2

[0027] A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles includes the following steps:

[0028] (1) Mixing: The diamond / copper thermal conductive material powder used has the following composition: 20wt.% diamond with a particle size of 200-250μm, 0.5wt.% copper powder with an average size of 30nm, and the balance being electrolytic copper powder with a particle size of 150μm (metal powder purity ≥99.9%). Weigh the above powder, mix it evenly, sieve it and set it aside for later use. Pour the additive solution into a mixing tank containing the mixed powder, and mix it for 10 minutes under a 55G load using a resonant acoustic mixer. After standing for 5 minutes, a mixed slurry with a certain viscosity is obtained. The mass of the additive in the additive solution is 2% of the composite material powder, of which polyethylene glycol accounts for 60wt.% and carboxymethyl cellulose accounts for 40wt.%. The solvent is deionized water, and the mass of the solvent is 30% of the mass of the composite material.

[0029] (2) Molding: The above-mentioned mixed slurry is injected into the material tank of a high-precision roller coating machine, and the slurry is transferred to the copper mesh carrier belt by the rotation of the coating roller. The scraper movement speed is set to 250 mm / min and the scraper gap is 1.0 mm, thus obtaining pure copper + diamond / copper material. The drying temperature is set to 45℃ to remove the solvent in the slurry spread on the substrate, so that the diamond / copper adheres well to the copper mesh. The above operation is repeated with a pure copper powder tank and the scraper gap is set to 1.3 mm. A layer of copper powder with a particle size of 150 μm is then coated on the surface of the diamond / copper material to form a three-layer structure of pure copper + diamond / copper + pure copper. Then, a high-precision roller is used to obtain a high density and tightly bonded composite material under pressure. Finally, the material is released by a non-powered roller. The diamond / copper thermal conductive material preform is laid flat on the laser slitting platform, and the appropriate laser focal length is adjusted to cut a circular diamond / copper thermal conductive material preform with an outer diameter of 30 mm.

[0030] (3) Degreasing and sintering: The above diamond / copper thermal conductive material preform is placed in a graphite mold sprayed with BN release agent. The temperature is raised to 300°C at an initial pressure of 0.5 MPa and held for 10 min to degrease. Then the pressure is raised to 60 MPa and the temperature is raised to 1000°C at a heating rate of 10°C and held for 15 min. Finally, the furnace is cooled to 300°C to release the gas and vacuum. After cooling to room temperature, the mold is removed to obtain a highly dense diamond / copper thermal conductive material.

[0031] (4) Machining: The pure copper layer on the upper and lower surfaces of the sintered diamond / copper thermal conductive material is ground by a ceramic grinding wheel and then mechanically polished to obtain a bright surface, thus preparing a diamond / copper thermal conductive material with low surface roughness and high precision.

[0032] Example 3

[0033] A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles includes the following steps:

[0034] (1) Mixing: The diamond / copper thermal conductive material powder used is composed of: 55wt.% diamond with a particle size of 50-60μm, 5wt.% titanium powder with a particle size of 200nm, and the balance being electrolytic copper powder with an average size of 15μm (metal powder purity ≥99.9%). The above powders are weighed, mixed evenly, sieved, and set aside for later use. The additive solution is introduced into a mixing tank containing the mixed powder, and mixed for 8 minutes under a 45G load using a resonant acoustic mixer. After standing for 3 minutes, a mixed slurry with a certain viscosity is obtained. The mass of the additives in the additive solution is 10% of the raw materials of the composite material. The additives include dioctyl phthalate and polyvinyl chloride, of which dioctyl phthalate accounts for 70wt.% and polyvinyl chloride accounts for 30wt.%. The solvent is acetone, and the mass of the solvent is 10% of the mass of the composite material powder.

[0035] (2) Molding: The above-mentioned mixed paste is injected into the material tank of a high-precision roller coater, and the slurry is transferred to the copper foil carrier by the rotation of the coating roller. The scraper movement speed is set to 100 mm / min and the scraper gap is 2.5 mm, thus obtaining pure copper + diamond / copper material. The drying temperature is set to 50℃ to remove the solvent in the slurry spread on the substrate, so that the diamond / copper adheres well to the copper foil. The above operation is repeated with a pure copper powder tank and the scraper gap is set to 0.2 mm. A layer of copper powder with a particle size of 10 μm is then coated on the surface of the diamond / copper material to form a three-layer structure of pure copper + diamond / copper + pure copper. Then, a high-precision roller is used to obtain a high-density and tightly bonded composite material under pressure. Finally, the material is released by a non-powered roller. The diamond / copper thermal conductive material preform is laid flat on the laser slitting platform, and the appropriate laser focal length is adjusted to cut a circular diamond / copper thermal conductive material preform with an outer diameter of 30 mm.

[0036] (3) Degreasing and sintering: The above diamond / copper thermal conductive material preform is placed in a graphite mold sprayed with BN release agent. The temperature is raised to 400°C at an initial pressure of 1 MPa and a heating rate of 7°C / min. The temperature is held for 5 min to degrease and remove a small amount of binder. Then the pressure is raised to 50 MPa and the temperature is raised to 900°C at a heating rate of 10°C / min. The temperature is held for 15 min and the pressure is maintained. Finally, the temperature is cooled to 300°C in the furnace to release the gas and vacuum. After cooling to room temperature, the mold is removed to obtain a high-density diamond / copper thermal conductive material.

[0037] (4) Machining: The pure copper layer on the upper and lower surfaces of the sintered diamond / copper thermal conductive material is ground with a white corundum grinding wheel, then resin inlay is used, and then mechanical polishing is performed to obtain a bright surface, thus preparing a diamond / copper thermal conductive material with low surface roughness and high precision.

[0038] Example 4

[0039] A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles includes the following steps:

[0040] (1) Mixing: The diamond / copper thermal conductive material powder used has the following composition: 35wt.% diamond with a particle size of 150-200μm, 1wt.% chromium powder with a particle size of 2nm, and the balance being electrolytic copper powder with an average size of 100μm (metal powder purity ≥99.9%). Weigh the above powders, mix them evenly, sieve them, and set aside for later use. The additive solution is introduced into a mixing tank containing the mixed powder, and mixed for 8 minutes under a 45G load using a resonant acoustic mixer. After standing for 3 minutes, a mixed slurry with a certain viscosity is obtained. The mass of the additives in the additive solution is 2% of the raw material of the composite material. The additives include polyvinyl butyral, sodium alginate, and polyvinyl acetate, of which polyvinyl acetate accounts for 30wt.%, polyvinyl butyral accounts for 40wt.%, and sodium alginate accounts for 30wt.%. The solvent is toluene, and the mass of the solvent is 10% of the mass of the composite material powder.

[0041] (2) Molding: The above-mentioned mixed paste is injected into the material tank of a high-precision roller coater, and the slurry is transferred to the copper foil carrier by the rotation of the coating roller. The scraper movement speed is set to 100 mm / min and the scraper gap is 60 mm, thus obtaining pure copper + diamond / copper material. The drying temperature is set to 50℃ to remove the solvent in the slurry spread on the substrate, so that the diamond / copper adheres well to the copper foil. The above operation is repeated with a pure copper powder tank and the scraper gap is set to 100 mm. A layer of copper powder with a particle size of 100 μm is coated on the surface of the diamond / copper material to form a three-layer structure of pure copper + diamond / copper + pure copper. Then, a high-precision roller is used to obtain a high-density and tightly bonded composite material under pressure. Finally, it is passed through a non-powered roller to release stress. The diamond / copper thermal conductive material preform is laid flat on the laser slitting platform, and the appropriate laser focal length is adjusted to cut a circular diamond / copper thermal conductive material preform with an outer diameter of 50 mm.

[0042] (3) Degreasing and sintering: The above diamond / copper thermal conductive material preform is placed in a graphite mold sprayed with BN release agent. The temperature is raised to 330°C at an initial pressure of 2MPa and a heating rate of 10°C / min. The temperature is held for 15min to degrease and remove a small amount of binder. Then the pressure is raised to 80MPa and the temperature is raised to 950°C at a heating rate of 8°C / min. The temperature is held for 18min and the pressure is maintained. Finally, the furnace is cooled to 300°C to release the gas and vacuum. After cooling to room temperature, the mold is removed to obtain a high-density diamond / copper thermal conductive material.

[0043] (4) Machining: The pure copper layer on the upper and lower surfaces of the sintered diamond / copper thermal conductive material is ground with a white corundum grinding wheel, and then resin inlay is used to obtain a bright surface through mechanical polishing, thus preparing a diamond / copper thermal conductive material with low surface roughness and high precision.

[0044] Example 5

[0045] A method for preparing an easily processable diamond / copper thermal conductive material reinforced with nano-active particles differs from Example 1 in that the powder composition of the diamond / copper thermal conductive material used is as follows: 35 wt.% diamond with a particle size of 100-120 μm, 0.5 wt.% B powder with a size of 20 nm, and the balance being electrolytic copper powder with an average size of 50 μm (metal powder purity ≥ 99.9%).

[0046] Comparative Example 1

[0047] A method for preparing an easily processable diamond / copper thermal conductive material reinforced with nano-active particles differs from Example 1 in that the diamond / copper thermal conductive material powder composition is: 35wt.% diamond with a particle size of 100-120μm, and the balance being electrolytic copper powder with an average size of 50μm (metal powder purity ≥99.9%).

[0048] Comparative Example 2

[0049] A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles, differing from Example 1 in that the size of the B powder is 3 μm.

[0050] The thermal conductivity and density of the samples prepared in Examples 1-5, Comparative Examples 1 and 2 were tested respectively, and the test results are shown in Table 1.

[0051] Table 1 Performance Comparison Data of Embodiments of the Invention

[0052] Sample number Density Thermal conductivity W / mK Example 1 97.8％ 584 Example 2 97.5％ 523 Example 3 98.1％ 602 Example 4 97.6％ 583 Example 5 98.5％ 596 Comparative Example 1 90.23％ 385 Comparative Example 2 96.52％ 467

[0053] The thermal conductivity and density of the samples prepared in Examples 1-5 were better than those of the control samples. Under the same conditions, the nano-active elements significantly improved the density of the composite material. Moreover, the nano-elements have high activity during sintering and are easy to form alloy carbides with diamond at the interface. Therefore, the wettability of diamond and copper is improved, thereby improving the thermal conductivity of the composite material.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an easily processed diamond / copper thermally conductive material reinforced with nano-active particles, characterized in that, Includes the following steps: (1) Mixing: The mixture of copper powder, diamond and nano-reinforcing element powder is mixed with the additive solution to obtain a slurry; (2) Molding: The slurry is coated on the substrate carrier tape and heated and dried to solidify the slurry to form a diamond / copper layer. Then, a layer of copper powder is coated on the diamond / copper layer to form a preform of substrate + diamond / copper layer + copper powder layer. The preform is then pressed into shape. (3) Debinding and sintering: Diamond / copper thermal conductive material is obtained by sintering the pressed preform using a debinding and sintering process. (4) Machining: Grinding and polishing of diamond / copper thermal conductive materials; The mass percentage of each component in the mixed powder is as follows: diamond content is 20%-55%, nano-reinforcing element powder content is 0.5%-5%, and the balance is copper powder; In step (1), the copper powder is electrolytic copper powder with a particle size of 15-150 μm, and the diamond has a particle size of 50-250 μm. The particle size of the nano-reinforcing element powder is 2-500 nm, and the nano-reinforcing element powder is any one or a combination of copper powder, boron powder, titanium powder, cobalt powder or chromium powder.

2. The method for preparing the easily processed diamond / copper thermally conductive material reinforced with nano-active particles according to claim 1, characterized in that, The additive solution is prepared by dissolving the additive in a solvent, wherein the additive is a binder and a plasticizer; the amount of the solvent is 10-30% of the mass of the mixed powder; the amount of the additive is 2-10% of the mass of the mixed powder, wherein the plasticizer accounts for 30-70% of the mass of the additive, and the remainder is a binder.

3. The method for preparing the easily processed diamond / copper thermally conductive material reinforced with nano-active particles according to claim 2, characterized in that, The solvent is any one or a combination of ethanol, toluene, acetone, or deionized water; the binder is any one or a combination of polyvinyl alcohol, polyvinyl chloride, polymethyl methacrylate, polyvinyl butyral, sodium alginate, dextrin, gelatin, seaweed gum, carboxymethyl cellulose, or starch phosphate; the plasticizer is any one or a combination of polyethylene glycol, dioctyl phthalate, dibutyl phthalate, or polyvinyl acetate.

4. The method for preparing the easily processed diamond / copper thermally conductive material reinforced with nano-active particles according to claim 1, characterized in that, In step (2), the substrate is a copper film, copper foil, or copper mesh; the particle size of the copper powder in the copper powder layer is 10-100μm, and the thickness of the copper powder layer is 0.2-100mm.

5. The method for preparing the easily processed diamond / copper thermally conductive material reinforced with nano-active particles according to claim 1, characterized in that, The degreasing sintering process in step (3) involves cutting the pressed preform and placing it in a mold for vacuum hot pressing sintering or spark plasma sintering.

6. The method for preparing the easily processed diamond / copper thermally conductive material reinforced with nano-active particles according to claim 5, characterized in that, The process parameters for vacuum hot pressing sintering or spark plasma sintering are as follows: the initial pressure is below 2 MPa, the temperature is raised to 300-400 ℃ at a heating rate of 5-10 ℃ / min, held for 5-15 min for degreasing, then the temperature is raised to 900-1000 ℃ at a heating rate of 8-15 ℃ / min, the pressure is raised to 50-80 MPa, held for 15-20 min, and finally cooled to below 300 ℃ to release the gas and vacuum.

7. The nano-active particle-reinforced, easily processed diamond / copper thermal conductive material prepared by the method according to any one of claims 1-6.

Images