A method for preparing a copper-diamond / copper composite

Abstract

The application relates to a preparation method of a copper-diamond / copper composite material and belongs to the technical field of material preparation. The method is characterized in that diamond / copper material and clean and dry copper sheets are put into a hot-pressing furnace, a hot-pressing semi-melting process is adopted to perform pressure infiltration treatment, a copper-diamond / copper composite material blank is prepared, the copper layer on the surface of the blank is ground and polished, and a copper-diamond / copper composite material is obtained. The method enables the copper layer and the diamond / copper material to be tightly combined through interatomic diffusion through the semi-melting process, the thickness of the copper layer on the surface of the prepared material can be effectively controlled, and the combination of the copper layer and the diamond / copper material is more firm. Meanwhile, through the near-net-shape process, the copper layer can be subjected to conventional processing and then electroplated with gold, so that the corresponding product can be obtained, the preparation cost of the material is reduced to the maximum extent, and the technical problem that the diamond / copper composite material is difficult to process is solved.

Description

Technical Field

[0001] This invention relates to a method for preparing copper-diamond / copper composite materials, belonging to the field of materials preparation technology. Background Technology

[0002] With the rapid development of microwave communication and electronic packaging technologies, higher demands are being placed on chip heat dissipation. Traditional heat dissipation materials can no longer meet market needs. Diamond / copper composite materials, which combine high thermal conductivity and low expansion, can effectively address the heat dissipation requirements of chips. However, diamond / copper materials are characterized by high hardness and difficulty in processing, and traditional processing methods struggle to meet the quality and precision requirements of industrial-scale diamond / copper products.

[0003] Currently, the common processing methods for diamond / copper materials are laser processing and high-pressure water jet processing. Both methods damage the diamond particles at the processing boundaries, causing them to detach. Generally, processed diamond / copper materials require gold plating. Before gold plating, a layer of copper is electroplated onto the diamond / copper surface to form a copper-diamond / copper composite material, followed by gold plating. The purpose of copper plating is twofold: firstly, it fills the surface defects of the processed diamond / copper material to meet product performance requirements; secondly, the diamond / copper surface cannot be directly gold-plated and requires metallization treatment before gold plating. However, the copper electroplating process firstly generates a large amount of wastewater and exhaust gas, causing serious environmental pollution; secondly, the uniformity and stability of the electroplated copper layer are poor. Due to the uneven distribution of current during the electroplating process, the coating thickness may be uneven, resulting in defects such as "nodules" or "pinholes"; thirdly, the corrosion resistance of electroplated copper is poor. Although copper itself has a certain degree of corrosion resistance, the electroplated copper layer is often thin and is easily corroded by environmental factors. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide a method for preparing copper-diamond / copper composite materials. This method utilizes a semi-cladding process to achieve a tight bond between the copper layer and the diamond / copper material through interatomic diffusion. This allows for effective control of the copper layer thickness on the surface of the prepared copper-diamond / copper composite material, resulting in a stronger bond between the copper layer and the diamond / copper material. Furthermore, through a near-forming process, only conventional processing of the copper layer followed by electroplating with gold is required to obtain the desired product, minimizing material preparation costs and solving the technical problem of the difficulty in processing diamond / copper composite materials.

[0005] To achieve the objectives of this invention, the following technical solutions are provided.

[0006] A method for preparing a copper-diamond / copper composite material, the method comprising the following steps:

[0007] Diamond / copper material and clean, dry copper sheet are placed in a hot press furnace and subjected to pressure melting and infiltration treatment using a hot press semi-melting process to prepare a copper-diamond / copper composite material blank; the copper layer on the surface of the blank is ground and polished to obtain a copper-diamond / copper composite material.

[0008] The hot-press semi-melt cladding process conditions are as follows:

[0009] First stage: Increase the temperature from room temperature to 150℃ to 200℃ in 10min to 30min, keep the temperature constant for 10min to 20min, and increase the pressure from atmospheric pressure to 5MPa to 8MPa;

[0010] Second stage: Increase the temperature from 150℃ to 200℃ to 350℃ to 500℃ in 30min to 60min, keep it at a constant temperature for 10min to 30min, and increase the pressure from 5MPa to 8MPa to 10MPa to 12MPa.

[0011] The third stage: the temperature is increased from 350℃ to 500℃ to 550℃ to 650℃ in 30 min to 80 min, and then kept at a constant temperature for 10 min to 20 min, while the pressure is increased from 10MPa to 12MPa to 15MPa to 18MPa.

[0012] Fourth stage: The temperature is increased from 550℃ to 650℃ to 900℃ to 1050℃ in 60min to 120min, and then kept at a constant temperature for 10min to 30min, while the pressure is increased from 15MPa to 18MPa to 20MPa to 23MPa.

[0013] Fifth stage: Increase the temperature from 900℃ to 1050℃ to 1150℃ in 5 min to 15 min, keep it at a constant temperature for 30 min to 60 min, and increase the pressure from 20MPa to 23MPa to 25MPa to 30MPa.

[0014] Sixth stage: Reduce the temperature from 1050℃ to 1150℃ to 850℃ to 900℃ over 30 to 60 minutes, maintain the temperature for 10 to 20 minutes, and reduce the pressure from 25MPa to 30MPa to 13MPa to 18MPa.

[0015] Stage 7: Cooling from 850℃ to 900℃ to room temperature in the furnace, with the pressure decreasing from 13MPa to 18MPa to 0MPa.

[0016] Furthermore, the specific steps of the method are as follows:

[0017] Place copper sheet, diamond / copper material, and copper sheet on one side of the hot press mold cavity from bottom to top. Place the hot press mold with diamond / copper material and copper sheet in the center of the hot press furnace, being careful not to touch the heating element. After loading the furnace, adjust the pressure head of the hot press mold to be on the same horizontal plane and perform pressure melting and infiltration treatment.

[0018] The preferred copper sheet is a pure copper cold-rolled plate, with a chemical composition that meets the requirements of GB / T5231 standard, and a surface quality and condition that meet the requirements of GB / T2040 standard.

[0019] Preferably, the shape of the copper sheet corresponds to the cross-sectional shape of the inner cavity of the hot pressing mold.

[0020] Preferably, the thickness of the copper sheet is less than or equal to twice the thickness of the diamond / copper material; more preferably, the thickness of the copper sheet is 1mm to 5mm.

[0021] Preferably, the mass fraction of copper sheet on each side is 200% to 300%, based on the total mass of copper actually used for cladding being 100%.

[0022] Diamond / copper materials are composite materials formed from diamond and copper. In microwave communication and electronic packaging technologies, they are used as chip heat dissipation materials and can be prepared using conventional techniques in this field. Alternatively, they can be prepared using the following specific methods:

[0023] The phenolic resin solution is poured into a mixer containing diamond powder and copper powder with tungsten coating on the surface for mixing. After being mixed evenly, the mixture is dried to obtain the processed material, which is then pressed into a blank, which is the diamond / copper material.

[0024] The particle size of the diamond powder coated with the tungsten layer is 100μm to 500μm, and the thickness of the tungsten layer is 5nm to 50nm.

[0025] The preferred copper powder has a chemical composition that meets the requirements of GB / T5246 FTD1 and FTD2 copper powder standards; the preferred copper powder has a loose bulk density of 1.2 g / cm³. 3 ~2.0g / cm 3 The particle size of the copper powder is 40μm to 300μm.

[0026] The preferred volume ratio of diamond powder to copper powder for the tungsten coating layer is 30–70:70–30.

[0027] The phenolic resin solution is prepared by stirring and mixing phenolic resin and ethanol; preferably, the ratio of phenolic resin to ethanol is 1g:3ml to 20ml.

[0028] Preferably, the total mass of diamond powder and copper powder used for surface tungsten coating is 100%, and the mass fraction of phenolic resin is 0.5% to 10%.

[0029] The preferred mixing time is 30 min to 180 min, and the rotation speed is 60 r / min to 120 r / min.

[0030] The preferred drying method is to dry at 50℃~70℃ for 2h~8h, with the material being turned over every 15min~30min.

[0031] The preferred density of the diamond / copper material is 3.5 g / cm³. 3 ~5.5g / cm 3 .

[0032] Beneficial effects

[0033] (1) The present invention provides a method for preparing copper-diamond / copper composite material. The method uses a hot-press semi-cladding process to make the copper layer and diamond / copper material tightly bonded through interatomic diffusion, so that the thickness of the copper surface of the prepared copper-diamond / copper composite material can be effectively controlled, and the bonding between the copper layer and the diamond / copper material is stronger. It can prepare dense copper-diamond / copper material, which has high thermal conductivity and low expansion.

[0034] (2) The present invention provides a method for preparing a copper-diamond / copper composite material. The copper-diamond / copper composite material prepared by the method has a copper layer directly covering its surface. The adhesion of this copper layer is better than that of copper electroplating or evaporation on the diamond / copper surface. Therefore, the material does not need to be copper plated in the subsequent electroplating process. Nickel and gold can be plated directly on the surface. This optimizes the electroplating process, improves the coating quality of the product, minimizes the material preparation cost, and solves the technical problem of the difficulty in processing diamond / copper composite materials.

[0035] (3) The present invention provides a method for preparing copper-diamond / copper composite material. The main function of the first stage of the hot-pressing semi-cladding process in the method is to enable the thermosetting phenolic resin to decompose and form a certain porosity, so as to create a suitable environment for subsequent copper infiltration.

[0036] (4) The present invention provides a method for preparing copper-diamond / copper composite material. The main function of the second stage of the hot-pressing semi-cladding process in the method is to completely decompose the thermosetting resin and at the same time make the porosity formed inside the material reach the volume space required for copper infiltration.

[0037] (5) The present invention provides a method for preparing copper-diamond / copper composite material. In the third stage of the hot pressing semi-cladding process, since the furnace temperature and pressure have reached a certain level, in order to ensure that the hot pressing mold will not crack due to excessive heating and excessive pressure during mass production, it is necessary to keep it at the temperature for 10 min to 20 min in this stage.

[0038] (6) The present invention provides a method for preparing copper-diamond / copper composite material. The main function of the fourth stage of the hot-pressing semi-cladding process in the method is to soften the copper sheet, making the copper sheet more compact and creating conditions for the subsequent copper infiltration process.

[0039] (7) The present invention provides a method for preparing copper-diamond / copper composite material. The fifth stage of the hot-pressing semi-melting process is the key stage for copper infiltration. In this stage, the copper is in a semi-molten state. Under pressure, a portion of the copper can penetrate into the diamond / copper material, and another portion of the copper forms a copper layer on the surface of the diamond / copper material.

[0040] (8) The present invention provides a method for preparing copper-diamond / copper composite material. The main function of the sixth stage of the hot-pressing semi-cladding process in the method is to eliminate the stress at the connection between the surface copper layer and the diamond / copper material, and to ensure that the interface between the copper layer and the diamond / copper material will not crack due to the rapid decrease in temperature. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the hot-pressing semi-cladding process conditions in the preparation method of a copper-diamond / copper composite material according to the present invention. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the present invention.

[0043] The following embodiments illustrate the hot-pressing semi-cladding process conditions in a method for preparing a copper-diamond / copper composite material. Figure 1 As shown.

[0044] Example 1

[0045] A method for preparing a copper-diamond / copper composite material, the method comprising the following steps:

[0046] Step 1: Preparation of diamond / copper materials

[0047] (1) The average particle size of the diamond powder with the tungsten coating on the surface is 100 μm, and the average thickness of the tungsten coating on the surface is 5 nm.

[0048] The chemical composition of the copper powder meets the requirements of the copper powder standards in GB / T5246 FTD1 and FTD2, and the loose bulk density is 1.2 g / cm³. 3 The average particle size is 40 μm;

[0049] Pour 40g of phenolic resin into 120ml of ethanol and stir thoroughly until the phenolic resin is completely dissolved in the ethanol to prepare a phenolic resin solution.

[0050] (2) Prepare powder by mixing tungsten-coated diamond powder and copper powder in a volume ratio of 30:70. Weigh 1 kg of tungsten-coated diamond powder and 6 kg of copper powder and put them into a mixer. Then pour the phenolic resin solution into the mixer containing the tungsten-coated diamond powder and copper powder for mixing. Mix at 60 r / min for 30 min until the mixture is uniform. Then put the uniformly mixed material into an oven and dry at 50°C for 2 h. Turn the material over every 15 min to obtain the processed material.

[0051] (3) Select a manual press with a rated pressure of 65T. The inner cavity of the pressing mold is 12.7mm in diameter and 80mm in depth. Weigh 4g of the material processed in step (2) and load it into the pressing mold. Adjust the loading height to ensure that the material will not be removed from the mold. Press the material with a pressing force of 80% of the rated pressure, i.e., 52T, and hold it for 1s. Remove the pressed blank, which is the diamond / copper material. Measure the size and weight of the diamond / copper material with calipers and an electronic balance. The thickness is 9mm and the density is 3.5g / cm³. 3 .

[0052] Step 2: Preparation of copper-diamond / copper composite materials

[0053] (1) The copper sheet is a pure copper cold-rolled plate with a thickness of 2mm. Its chemical composition meets the requirements of GB / T5231 standard, and the surface quality and condition of the copper sheet meet the requirements of GB / T2040 standard.

[0054] The copper sheet was cut into a shape with a diameter of 12.7 mm, corresponding to the cross-sectional shape of the inner cavity of the hot pressing mold. The cut copper sheet was placed in an acetone solution for ultrasonic cleaning at a frequency of 15 kHz, an ultrasonic power of 120 W, a cleaning time of 10 min, and an ultrasonic cleaning temperature of 50 °C. After removal, it was cleaned twice with distilled water, then cleaned twice with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 50 °C for 30 min to obtain a clean and dry copper sheet.

[0055] (2) Place the clean and dry copper sheet on one side, the diamond / copper material prepared in step one (3), and the clean and dry copper sheet on the other side into the hot press mold cavity from bottom to top. The amount of copper sheet added on each side is 0.91g, that is, based on the total mass of copper actually used for cladding being 100%, the mass fraction of copper sheet on each side is 200%. Place the hot press mold containing the diamond / copper material and copper sheet into the center of the furnace of the hot press furnace, making sure it does not touch the heating element. After the furnace is loaded, adjust the pressure head of the hot press mold to be on the same horizontal plane and perform pressure melting treatment. The hot press semi-cladding process conditions are as follows:

[0056] First stage: Increase the temperature from room temperature to 150℃ in 10 minutes, maintain the temperature for 10 minutes, and increase the pressure from atmospheric pressure to 5MPa;

[0057] Second stage: Increase from 150℃ to 350℃ in 30 minutes, keep at a constant temperature for 10 minutes, and increase the pressure to 10MPa;

[0058] The third stage: the temperature is increased from 350℃ to 550℃ in 30 minutes, kept at a constant temperature for 10 minutes, and the pressure is increased to 15MPa.

[0059] Fourth stage: Increase from 550℃ to 900℃ in 60 minutes, maintain the temperature for 10 minutes, and increase the pressure to 20MPa;

[0060] Fifth stage: Increase from 900℃ to 1050℃ in 5 minutes, maintain the temperature for 30 minutes, and increase the pressure to 25MPa;

[0061] Stage 6: Reduce the temperature from 1050℃ to 850℃ in 30 minutes, maintain the temperature for 10 minutes, and reduce the pressure to 13MPa;

[0062] Stage 7: Cool from 850℃ to room temperature with the furnace, and reduce the pressure to 0MPa.

[0063] A copper-diamond / copper composite material blank was prepared; the copper layer surface of the blank was ground and polished to obtain a copper-diamond / copper composite material.

[0064] Performance testing:

[0065] (1) Density measurement

[0066] Based on the formula density = mass / volume, the density of the copper-diamond / copper composite material was measured to be ρ = 5.15 g / cm³. 3 .

[0067] (2) Thermal expansion measurement

[0068] The selected equipment was a German Netzsch-DIL 402C, with a measurement range of ±5000 μm, a resolution of 2 nm, and an inert argon atmosphere. The measured coefficient of thermal expansion of the copper-diamond / copper composite material was 8.2 × 10⁻⁶. -6 / K -1 .

[0069] (3) Thermal conductivity measurement

[0070] The selected equipment model was LFA 467HT, with a maximum heating rate of 50K / min and an inert argon atmosphere; the thermal conductivity of the copper-diamond / copper composite material was measured to be 525 (W / (m×K)).

[0071] In this embodiment, the thickness of the copper layer on the surface of the copper-diamond / copper composite material can be effectively controlled, resulting in a stronger bond between the copper layer and the diamond / copper. Furthermore, through a near-forming process, only the copper layer needs conventional processing before electroplating with gold.

[0072] Example 2

[0073] A method for preparing a copper-diamond / copper composite material, the method comprising the following steps:

[0074] Step 1: Preparation of diamond / copper materials

[0075] (1) The average particle size of the diamond powder with the tungsten coating on the surface is 500 μm, and the average thickness of the tungsten coating on the surface is 50 nm.

[0076] The chemical composition of the copper powder meets the requirements of GB / T5246 FTD1 and FTD2 copper powder standards: loose density is 2.0 g / cm³. 3 The average particle size of the copper powder is 300 μm;

[0077] Pour 200g of phenolic resin into 4L of ethanol and stir thoroughly until the phenolic resin is completely dissolved in the ethanol to prepare a phenolic resin solution.

[0078] (2) Prepare powder by mixing tungsten-coated diamond powder and copper powder in a volume ratio of 70:30. Weigh 1 kg of tungsten-coated diamond powder and 1.1 kg of copper powder and put them into a mixer. Then pour the phenolic resin solution into the mixer containing the tungsten-coated diamond powder and copper powder for mixing. Mix at 120 r / min for 180 min until the mixture is uniform. Then put the uniformly mixed material into an oven and dry at 70°C for 8 h. Turn the material over every 30 min to obtain the processed material.

[0079] (3) Select a manual press with a rated pressure of 65T. The inner cavity of the pressing mold has a diameter of 12.7mm and a depth of 80mm. Weigh 4g of the material processed in step (2) and load it into the pressing mold. Adjust the loading height to ensure that the material will not be removed from the mold. Press the material with a pressing force of 80% of the rated pressure, i.e., 52T, and hold it for 10s. Remove the pressed blank, which is the diamond / copper material. Measure the size and weight of the diamond / copper material with calipers and an electronic balance. The thickness is measured to be 7.2mm and the density is 4.4g / cm³. 3 .

[0080] Step 2: Preparation of copper-diamond / copper composite materials

[0081] (1) The copper sheet is pure copper cold-rolled plate with a thickness of 2mm. Its chemical composition meets the requirements of GB / T5231 standard, and the surface quality and condition of the copper sheet meet the requirements of GB / T2040 standard.

[0082] The copper sheet was cut into a shape with a diameter of 12.7 mm, corresponding to the cross-sectional shape of the inner cavity of the hot pressing mold. The cut copper sheet was placed in an acetone solution for ultrasonic cleaning at a frequency of 15 kHz, an ultrasonic power of 120 W, a cleaning time of 10 min, and an ultrasonic cleaning temperature of 50 °C. After removal, it was cleaned twice with distilled water, then cleaned twice with anhydrous ethanol, and then placed in a vacuum drying oven and dried at 50 °C for 30 min to obtain a clean and dry copper sheet.

[0083] (2) Place the clean and dry copper sheet on one side, the diamond / copper material prepared in step one (3), and the clean and dry copper sheet on the other side into the hot press mold cavity from bottom to top. The amount of copper sheet added on each side is 0.6g, that is, based on the total mass of copper actually used for cladding being 100%, the mass fraction of copper sheet on each side is 300%. Place the hot press mold containing the diamond / copper material and copper sheet into the center of the furnace of the hot press furnace, making sure it does not touch the heating element. After the furnace is loaded, adjust the pressure head of the hot press mold to be on the same horizontal plane and perform pressure melting treatment. The hot press semi-cladding process conditions are as follows:

[0084] First stage: Increase the temperature from room temperature to 200℃ in 30 minutes, maintain the temperature for 20 minutes, and increase the pressure to 8MPa;

[0085] Second stage: Increase the temperature from 200℃ to 500℃ in 60 minutes, keep it at a constant temperature for 30 minutes, and increase the pressure to 12MPa;

[0086] Third stage: Increase the temperature from 500℃ to 650℃ in 80 minutes, keep it at a constant temperature for 20 minutes, and increase the pressure to 18MPa;

[0087] Fourth stage: Increase the temperature from 650℃ to 1050℃ in 120 minutes, maintain the temperature for 30 minutes, and increase the pressure to 23MPa;

[0088] Fifth stage: Increase the temperature from 1050℃ to 1150℃ in 15 minutes, maintain the temperature for 60 minutes, and increase the pressure to 30MPa;

[0089] Stage 6: Reduce the temperature from 1150℃ to 900℃ over 60 minutes, maintain the temperature for 20 minutes, and reduce the pressure to 18MPa.

[0090] Stage 7: Cool from 900℃ to room temperature with the furnace, and reduce the pressure to 0MPa.

[0091] A copper-diamond / copper composite material blank was prepared; the copper layer on the surface of the blank was ground and polished to obtain a copper-diamond / copper composite material.

[0092] Performance testing:

[0093] (1) Density measurement

[0094] Based on the formula density = mass / volume, the density of the copper-diamond / copper composite material was measured to be ρ = 5.1 g / cm³. 3 .

[0095] (2) Expansion measurement

[0096] The selected equipment was a German Netzsch-DIL 402C, with a measurement range of ±5000 μm, a resolution of 2 nm, and an inert argon atmosphere. The measured coefficient of thermal expansion of the copper-diamond / copper composite material was 8.0 × 10⁻⁶. -6 / K -1 .

[0097] (3) Thermal conductivity measurement

[0098] The selected equipment model was LFA 467HT, with a maximum heating rate of 50K / min and an inert argon atmosphere; the thermal conductivity of the copper-diamond / copper composite material was measured to be 495 (W / (m×K)).

[0099] In this embodiment, the thickness of the copper layer on the surface of the copper-diamond / copper composite material can be effectively controlled, resulting in a stronger bond between the copper layer and the diamond / copper. Furthermore, through a near-forming process, the desired product can be obtained by performing only conventional processing on the copper layer followed by electroplating with gold.

Claims

1. A method for preparing a copper-diamond / copper composite material, characterized in that: Diamond / copper material and clean, dry copper sheet are placed in a hot press furnace and subjected to pressure melting and infiltration treatment using a hot press semi-melting process to prepare a copper-diamond / copper composite material blank; the copper layer on the surface of the blank is ground and polished to obtain a copper-diamond / copper composite material. The hot-press semi-melt cladding process conditions are as follows: First stage: Increase the temperature from room temperature to 150℃ to 200℃ in 10min to 30min, keep the temperature constant for 10min to 20min, and increase the pressure from atmospheric pressure to 5MPa to 8MPa; Second stage: Increase the temperature from 150℃ to 200℃ to 350℃ to 500℃ in 30min to 60min, keep it at a constant temperature for 10min to 30min, and increase the pressure from 5MPa to 8MPa to 10MPa to 12MPa. The third stage: the temperature is increased from 350℃ to 500℃ to 550℃ to 650℃ in 30 min to 80 min, and then kept at a constant temperature for 10 min to 20 min, while the pressure is increased from 10MPa to 12MPa to 15MPa to 18MPa. Fourth stage: The temperature is increased from 550℃ to 650℃ to 900℃ to 1050℃ in 60min to 120min, and then kept at a constant temperature for 10min to 30min, while the pressure is increased from 15MPa to 18MPa to 20MPa to 23MPa. Fifth stage: Increase the temperature from 900℃ to 1050℃ to 1150℃ in 5 min to 15 min, keep it at a constant temperature for 30 min to 60 min, and increase the pressure from 20MPa to 23MPa to 25MPa to 30MPa. Sixth stage: Reduce the temperature from 1050℃ to 1150℃ to 850℃ to 900℃ over 30 to 60 minutes, maintain the temperature for 10 to 20 minutes, and reduce the pressure from 25MPa to 30MPa to 13MPa to 18MPa. Stage 7: Cooling from 850℃ to 900℃ to room temperature in the furnace, with the pressure decreasing from 13MPa to 18MPa to 0MPa.

2. The method for preparing a copper-diamond / copper composite material according to claim 1, characterized in that: The specific steps of the method are as follows: Place a copper sheet, a diamond / copper material, and a copper sheet on one side of the hot press mold cavity from bottom to top. Place the hot press mold containing the diamond / copper material and copper sheet into the center of the hot press furnace. After loading the furnace, adjust the pressure head of the hot press mold to be on the same horizontal plane and perform pressure melting and infiltration treatment.

3. The method for preparing a copper-diamond / copper composite material according to claim 1 or 2, characterized in that: The copper sheet is a pure copper cold-rolled plate, and its chemical composition meets the requirements of GB / T5231 standard. The surface quality and condition of the copper sheet meet the requirements of GB / T2040 standard. The shape of the copper sheet corresponds to the cross-sectional shape of the inner cavity of the hot pressing mold; The thickness of the copper sheet is less than or equal to twice the thickness of the diamond / copper material; Assuming the total mass of copper actually used for cladding is 100%, the mass fraction of copper sheet on each side is 200% to 300%.

4. The method for preparing a copper-diamond / copper composite material according to claim 3, characterized in that: The thickness of the copper sheet is 1mm to 5mm; the density of the diamond / copper material is 3.5g / cm³. 3 ~5.5g / cm 3 .

5. A method for preparing a copper-diamond / copper composite material according to claim 1 or 2, characterized in that: Diamond / copper materials are prepared by the following method: The phenolic resin solution is poured into a mixer containing diamond powder and copper powder with tungsten coating on the surface for mixing. After being mixed evenly, the mixture is dried to obtain the processed material, which is then pressed into a blank, which is the diamond / copper material. The particle size of the diamond powder coated with the tungsten layer is 100μm to 500μm, and the thickness of the tungsten layer is 5nm to 50nm.

6. The method for preparing a copper-diamond / copper composite material according to claim 5, characterized in that: The chemical composition of the copper powder meets the requirements of GB / T5246 FTD1 and FTD2 copper powder standards; the loose density of the copper powder is 1.2 g / cm³. 3 ~2.0g / cm 3 The particle size of the copper powder is 40μm to 300μm.

7. The method for preparing a copper-diamond / copper composite material according to claim 5, characterized in that: The volume ratio of diamond powder to copper powder in the tungsten-plated layer is 30-70:70-30. The phenolic resin solution is prepared by stirring and mixing phenolic resin and ethanol, with a ratio of phenolic resin to ethanol of 1g:3ml to 20ml. The total mass of diamond powder and copper powder used for surface tungsten coating is 100%, and the mass fraction of phenolic resin is 0.5% to 10%.

8. The method for preparing a copper-diamond / copper composite material according to claim 5, characterized in that: The mixing time is 30 min to 180 min, and the rotation speed is 60 r / min to 120 r / min.

9. The method for preparing a copper-diamond / copper composite material according to claim 5, characterized in that: Drying is carried out at 50℃~70℃ for 2h~8h, with turning over every 15min~30min.

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