High thermal conductivity diamond / copper composite material and preparation method thereof

Abstract

The application discloses a kind of high thermal conductivity diamond / copper composite material and preparation method thereof, belong to the field of composite material.It is prepared as follows: 1) etching treatment is carried out to diamond particles;2) sputtering tungsten layer is formed on the surface of diamond by magnetron sputtering, then high temperature treatment is carried out, finally copper layer is sputtered by magnetron sputtering;3) the copper-plated diamond particles are mixed with copper powder, and discharge plasma sintering is carried out;Discharge plasma sintering is as follows: set pre-pressing pressure to increase temperature, when temperature is close to target sintering temperature, increase pressure to 44-55Mpa instantly, target sintering temperature is 750-950℃, after temperature is increased to target sintering temperature, keep pressure to cool down and anneal, and high thermal conductivity diamond / copper composite material is obtained.The application has the advantages of simple and rapid process, low energy consumption, good repeatability, the obtained composite material is more dense, realizes the preparation of high thermal conductivity diamond / copper composite material with low diamond volume fraction, effectively reduces the cost, and has important application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of composite materials, and particularly relates to a high-thermal-conductivity diamond / copper composite thermal conductive material and a preparation method thereof. BACKGROUND

[0002] With the wide application of high-power, small-size and highly integrated semiconductor devices and various chips in the fields of 5G communication, national defense and military industry, aerospace, transportation, etc., the manufacturing process of chips is becoming more and more fine. Especially with the rapid development of AI technology and the rapid increase in demand for computer cloud servers, the demand for AI computing power has led to a rapid increase in device heat flux with the increase in power. If heat dissipation is not timely, the device temperature will exceed the limit, which will seriously reduce the performance and service life of the device. System failures caused by device heat dissipation problems have become the biggest risk in engineering. Traditional heat dissipation materials are difficult to meet the high-efficiency heat dissipation needs of devices, and it is of great significance to develop new diamond-based composite heat dissipation materials with ultra-high thermal conductivity.

[0003] Diamond is the material with the highest thermal conductivity in nature (up to 2200 W / mK-2400 W / mK), but elemental diamond is difficult to process, and the thermal expansion coefficient cannot be controlled. Preparing a composite material with diamond as the reinforcing base and copper as the matrix can overcome the above shortcomings. By changing the content of diamond, the thermal expansion coefficient and density of the composite material can be changed. During the sintering process of the diamond composite material, due to the low bonding force between copper powder and diamond, the sample has many air gaps and low density, which makes it difficult to improve the performance of the directly compounded sample.

[0004] Traditional interface modification is to coat a layer of metal (such as Cr, Ti, W, etc.) on the surface of diamond and perform heat treatment through various technologies and methods. Dou Wenjie et al. prepared an interface transition layer of Diamond-W2C-WC-W by controlling the interface between diamond and plated tungsten, and then prepared a composite material with a thermal conductivity of 655 W / mK under the condition of a diamond volume fraction of 90% by using a six-surface press at high temperature and high pressure. Pan Yanhong et al. first coated W on the surface of diamond to form a carbide interface by salt bath method, then coated copper to form the interface between diamond copper and carbide by chemical plating, and finally prepared a diamond / copper composite material with a thermal conductivity of 588-672 W / mK under the condition of a diamond volume fraction of 50-70% by vacuum pressureless infiltration method. Wu Zhenwang et al. from Zhengzhou University prepared a thermal conductive sheet by sintering after modifying the single plated tungsten element and using a discharge plasma, and the thermal conductivity of the prepared thermal conductive sheet was only 554.7 W / mK, and the volume fraction was 60%.

[0005] However, the diamond content in the above method is too high, so the preparation cost is high and it is difficult to be applied in industry; and there are problems of poor interface bonding between the diamond and the copper matrix and high interface thermal resistance, so the thermal conductivity of the obtained composite diamond is still far from the theoretical value (900 W / mK). SUMMARY

[0006] The present application aims at providing a high-thermal-conductivity diamond / copper composite thermal conductive material and a preparation method thereof to overcome the shortcomings of the prior art.

[0007] To achieve the object of the present application, the technical scheme adopted is as follows:

[0008] The present application provides a preparation method of a high-thermal-conductivity diamond / copper composite material, which comprises the following steps:

[0009] 1) etching treatment of diamond particles;

[0010] 2) sputtering a tungsten layer on the etched diamond surface obtained in step 1) by magnetron sputtering, then high-temperature treatment, and finally sputtering a copper layer by magnetron sputtering;

[0011] 3) mixing the copper-plated diamond particles obtained in step 2) with copper powder, and performing discharge plasma sintering, wherein the discharge plasma sintering is as follows: setting a pre-pressing pressure and increasing the temperature, instantaneously increasing the pressure to 44-55 MPa when the temperature approaches the target sintering temperature, the target sintering temperature being 750-950℃, maintaining the pressure after the temperature is increased to the target sintering temperature, and then cooling and annealing, to obtain the high-thermal-conductivity diamond / copper composite material.

[0012] In step 1), the etching treatment is etching treatment with a strong acid; the strong acid is aqua regia (hydrochloric acid: nitric acid = 3:1 by volume).

[0013] Preferably, the etching of the diamond with a strong acid is as follows: roughening the diamond particles with a strong acid at a temperature of 40-60℃ for 30-60 min, then cleaning with deionized water, ultrasonic cleaning, and finally drying.

[0014] Preferably, the diamond is cleaned before etching, and the cleaning process is as follows: ultrasonic cleaning of the diamond particles with a solution of acetone and ethanol, rinsing the diamond with deionized water after the ultrasonic cleaning is completed, and finally drying.

[0015] In the step 2), the sputtering of the tungsten layer is performed by adjusting the vibration frequency to 174-186 Hz, vacuumizing to below 0.5 Pa, heating to 100-150 DEG C and keeping for 5-10 min, and filling a certain amount of argon protective gas to reach the sputtering condition.

[0016] In the step 2), the high-temperature treatment process is as follows: in the argon atmosphere, keeping at 1100-1150 DEG C for 60-360 min. Preferably, the heating rate is 10-20 DEG C / min, and the argon protective gas is introduced at a flow rate of 100-150 mL / min.

[0017] In the step 2), the sputtering of the copper layer is performed by adjusting the vibration frequency to 174-186 Hz, vacuumizing to below 0.5 Pa, heating to 100-150 DEG C and keeping for 5-10 min, and filling a certain amount of argon protective gas to reach the sputtering condition.

[0018] In the step 2), the thickness of the sputtered tungsten layer is 60-80 nm.

[0019] In the step 2), the thickness of the sputtered copper layer is 20-30 nm.

[0020] In the step 3), the spark plasma sintering is performed by adjusting the pre-pressing pressure at the beginning of the heating stage to 8-10 MPa, increasing the pressure at the last 50-70 s of the heating stage to 44-55 MPa, keeping the pressure after heating to the target sintering temperature of 750-950 DEG C for cooling annealing, and unloading the pressure to 8-10 MPa after cooling to 500-650 DEG C to obtain the high-thermal-conductivity diamond / copper composite material. The initial pre-pressing pressure is set to increase the temperature, which is beneficial to form a better channel for removing pores in the composite material at the initial pressurizing and heating stage, and is beneficial to the subsequent densification. Then, the pressure is increased when approaching the target sintering temperature, and the pressure is kept after cooling annealing after heating to the target sintering temperature, which is beneficial to obtain the diamond / copper composite material with high density and good thermal conduction path continuity.

[0021] Preferably, the initial heating rate is 75-100 DEG C / min, and the heating rate is adjusted to 150-200 DEG C / min when the pressurizing starts.

[0022] In the step 3), the cooling rate of the cooling annealing stage is 30-60 DEG C / min. After heating to the target temperature, the pressure is kept at 44-55 MPa to control the cooling rate to 30-60 DEG C / min, and then the pressure is unloaded to 8-10 MPa after cooling to 500-650 DEG C, and the composite material is naturally cooled to room temperature.

[0023] According to the above scheme, in the step 3), the volume of the diamond particles is 30-35% of the total volume of the diamond particles and the copper powder.

[0024] The application provides the high-thermal-conductivity diamond / copper composite material prepared by the preparation method.

[0025] According to the above scheme, in the high-thermal-conductivity diamond / copper composite material, the volume fraction of the diamond is 30-35%.

[0026] According to the above scheme, the thermal conductivity of the diamond / copper composite material is 661-734 W / mK.

[0027] The application has the following beneficial effects:

[0028] 1. The application provides a preparation method of a high-thermal-conductivity diamond / copper composite material, wherein W / Cu double plating layers are plated on the surface of diamond by using a magnetron sputtering, a gradient layer of W2C-WC-W-Cu is formed on the surface of the diamond, a perfect heat transfer channel from phonon to electron is formed, the diamond and the copper matrix are closely combined, and the thermal conductivity of the diamond / copper composite material is improved; the diamond with the W / Cu double plating layers is mixed with copper powder, and then is sintered by instant pressurization and temperature rising by cooperating with a specific spark plasma sintering process system, and the sintering is cooled without maintaining pressure after maintaining temperature, so that the preparation of the high-thermal-conductivity diamond / copper composite material with a low diamond volume fraction (30-35%) (the thermal conductivity can be as high as 734 W / mK) is realized, the cost is effectively reduced, and the application prospect is important.

[0029] 2. The application does not need to maintain temperature after reaching the target sintering temperature of the spark plasma sintering process, directly maintains pressure and cools, shortens the production cycle, reduces the energy consumption, and is sintered by using a commercial spark plasma sintering furnace, so that the application is simple, fast, good in repeatability, and suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a schematic diagram for preparing the diamond double plating layer in Example 1.

[0031] Figure 2 It is an SEM diagram of the diamond after pretreatment in step S1 of Example 1. Figure 2 A and 2B are different magnifications.

[0032] Figure 3 It is an SEM diagram of the diamond after magnetron sputtering of tungsten in step S2 of Example 1. Figure 3 A and 3B are different magnifications.

[0033] Figure 4 It is an XRD diagram of the diamond after heat treatment in step S3 of Example 1.

[0034] Figure 5 The image shown is a SEM image of the diamond after heat treatment in step S3 of Example 1. Figure 5 A and 5B represent different magnifications.

[0035] Figure 6 This is a SEM image of copper after diamond magnetron sputtering in step S4 of Example 1, where... Figure 6 A and 6B represent different magnifications.

[0036] Figure 7 The image shown is the XRD pattern of diamond after heat treatment in step S3 of Example 2.

[0037] Figure 8 This is a SEM image of the diamond after heat treatment in step S3 of Example 2, where... Figure 8 A and 8B represent different magnifications.

[0038] Figure 9 This is a SEM image of copper after diamond magnetron sputtering in step S4 of Example 2, where... Figure 9 A and 9B represent different magnifications.

[0039] Figure 10 The image shown is the XRD pattern of diamond after heat treatment in step S3 of Example 3.

[0040] Figure 11 The image shown is a SEM image of the diamond after heat treatment in step S3 of Example 3. Figure 11 A and 11B represent different magnifications.

[0041] Figure 12 This is a SEM image of copper after diamond magnetron sputtering in step S4 of Example 3, where... Figure 12 A and 12B represent different magnifications.

[0042] Figure 13 The image shown is the XRD pattern of diamond after heat treatment in step S3 of Example 4.

[0043] Figure 14 This is a SEM image of the diamond after heat treatment in step S3 of Example 4, where... Figure 14 A and 14B represent different magnifications.

[0044] Figure 15 This is a SEM image of copper after diamond magnetron sputtering in step S4 of Example 4, where... Figure 15 A and 15B represent different magnifications. Detailed Implementation

[0045] The following examples further illustrate how to prepare double-coated diamond / copper composite materials under constant pressure conditions.

[0046] Example 1

[0047] A preparation method of high-thermal-conductivity diamond / copper composite material is provided, comprising the following steps:

[0048] S1: Pretreatment of diamond:

[0049] The diamond particles are cleaned using an acetone and ethanol solution at an ultrasonic frequency of 30 KHz for 30 min, and after the ultrasonic cleaning is completed, the diamond is rinsed with deionized water and dried at a temperature of 85°C in a drying oven; the diamond particles are roughened using a 50°C aqua regia solution for about 40 min, rinsed with deionized water and cleaned at an ultrasonic frequency of 30 KHz for 30 min, and dried at a temperature of 85°C to obtain pretreated diamond particles. Figure 2 As can be seen from the SEM image, the diamond after aqua regia treatment has etching on the surface, which helps the adhesion of the plating layer on the surface of the diamond.

[0050] S2: Magnetron sputtering of a tungsten layer on the diamond:

[0051] A certain amount of pretreated diamond is placed in the tray of a magnetron sputtering instrument, the vibration frequency (186 Hz) is adjusted so that the diamond rotates and jumps up to be fully sputtered to the metal W, vacuum is extracted to a degree of vacuum of less than 0.5 Pa, the tray is heated to a temperature of 150°C and kept for 10 min, a certain amount of argon protective gas is filled to reach the sputtering ignition condition, and a W layer of 80 nm is sputtered. Figure 3 As can be seen from the SEM image, the tungsten plating layer is firmly attached to the surface of the diamond, and has high density, which is conducive to increasing the bonding force between the diamond and copper during subsequent firing.

[0052] S3: Heat treatment:

[0053] The diamond after magnetron sputtering is subjected to high-temperature heat treatment in a tube furnace, an appropriate amount of tungsten-plated diamond is weighed and placed in a corundum crucible, which is placed in the tube furnace, the furnace door is closed to ensure airtightness, a mechanical pump is used to extract vacuum, argon is introduced to remove air to maintain an argon atmosphere in the furnace, and this cycle is repeated three times, the temperature program is set to a temperature increase rate of 20°C / min, argon protective gas with a flow rate of 150 mL / min is introduced into the tube furnace, the temperature is kept at 1100°C for 240 min, and the sample is taken after natural cooling.

[0054] S4: Magnetron sputtering of a Cu layer:

[0055] A certain amount of heat-treated diamond was placed into the tray of the magnetron sputtering instrument. The vibration frequency (186 Hz) was adjusted to ensure the diamond could rotate and bounce, allowing it to fully sputter onto the metallic Cu. A vacuum was then created, bringing the vacuum level below 0.5 Pa. The tray temperature reached 150°C and was held for 10 minutes. A certain amount of argon protective gas was then introduced to meet the sputtering conditions. A 30 nm Cu layer was sputtered.

[0056] S5: Spark Plasma Sintering (SPS)

[0057] W / Cu double-coated diamond and copper powder were mixed at a volume ratio of 3.5:6.5. The mixed sample was placed in a graphite cylindrical mold with an inner diameter of 13 mm. Vacuum was drawn, and the temperature was raised to 800 °C at a rate of 100 °C / min and a pressure of 8 MPa. The pressure was then increased to 50 MPa, and the temperature was raised to 950 °C at a rate of 150 °C / min for 1 min. The pressure was then maintained at 50 MPa, and the temperature was lowered at a rate of 60 °C / min until it reached 650 °C. The pressure was then reduced to 8 MPa, and the mixture was allowed to cool naturally to obtain the target product, a diamond-copper composite material, with a thermal conductivity of 734 W / mK.

[0058] Figures 4-6 The figures show the XRD pattern of the diamond after heat treatment in step S3, the SEM pattern of the diamond after heat treatment in step S3, and the SEM pattern of the diamond after magnetron sputtering of copper in step S4, respectively. The figures show that the diamond particles form a dense and smooth surface coating layer after magnetron sputtering and heat treatment. Analysis of the XRD patterns reveals that the coating layer on the diamond surface is a W2C-WC-W gradient layer, which enables a tight bond between copper and diamond, promoting improved interfacial thermal conductivity of the composite material.

[0059] Example 2

[0060] A method for preparing a high thermal conductivity diamond / copper composite material is provided, comprising the following steps:

[0061] S1: Diamond pretreatment

[0062] Diamond particles were cleaned with acetone and ethanol solution at a 20 kHz ultrasonic frequency for 20 min. After ultrasonic cleaning, the diamond particles were rinsed with deionized water and dried in a drying oven at 80°C. The diamond particles were then roughened with a 40°C aqua regia solution for about 30 min, rinsed with deionized water, and cleaned with 20 kHz ultrasonic frequency. The roughened diamond particles were then dried at 80°C to obtain pretreated diamond particles.

[0063] S2: A tungsten-coated diamond is obtained by magnetron sputtering a tungsten layer onto the diamond surface.

[0064] A certain amount of pretreated diamond is placed in the tray of the magnetron sputtering instrument, the vibration frequency (174 Hz) is adjusted, the diamond is rotated to jump up to be able to fully sputter to the metal W. Vacuum is extracted, the vacuum degree is below 0.5 Pa, the tray temperature is heated to 100 ℃ and kept for 5 min, a certain amount of argon protection gas is filled to reach the sputtering ignition condition. A 60 nm W layer is sputtered.

[0065] S3: heat treatment

[0066] The magnetron sputtered diamond is subjected to high-temperature heat treatment by a tube furnace, a proper amount of tungsten-plated diamond is placed in a corundum crucible, which is placed in the tube furnace, the furnace door is closed to ensure airtightness; a mechanical pump is used to extract vacuum, argon is introduced to remove air to maintain an argon atmosphere in the furnace, which is circulated three times; the temperature rising program is set to a temperature rising rate of 10 ℃ / min, argon protection gas with a flow rate of 100 mL / min is introduced into the tube furnace, the temperature is kept at 1150 ℃ for 60 min, and the sample is taken out after natural cooling.

[0067] S4: magnetron sputtering of Cu layer

[0068] A certain amount of heat-treated diamond is placed in the tray of the magnetron sputtering instrument, the vibration frequency (174 Hz) is adjusted, the diamond is rotated to jump up to be able to fully sputter to the metal Cu. Vacuum is extracted, the vacuum degree is below 0.5 Pa; the tray temperature is heated to 100 ℃ and kept for 5 min, a certain amount of argon protection gas is filled to reach the sputtering condition. A 20 nm Cu layer is sputtered.

[0069] S5: spark plasma sintering (SPS)

[0070] The W / Cu double-plated diamond and copper powder are mixed in a volume ratio of 3:7. The mixed sample is placed in a graphite cylindrical mold with an inner diameter of 13 mm. Vacuum is extracted, the temperature rising rate is 75 ℃ / min, the pressure is 15 MPa, the temperature is raised to 600 ℃, the pressure is increased to 55 MPa, and the temperature is raised to 750 ℃ at a rate of 150 ℃ / min for 1 min; then the pressure is reduced to 8 MPa when the temperature is reduced to 600 ℃ at a rate of 30 ℃ / min, and the target product diamond copper composite material is obtained by natural cooling, with a thermal conductivity of 661 W / mK.

[0071] Example 3

[0072] A method for preparing a high-thermal-conductivity diamond / copper composite material is provided, comprising the following steps:

[0073] S1: pretreatment of diamond: same as example 1

[0074] S2: magnetron sputtering of tungsten layer on diamond: same as example 1

[0075] S3: heat treatment: same as example 1

[0076] S4: magnetron sputtering Cu layer: same as example 1

[0077] S5: spark plasma sintering (SPS):

[0078] W / Cu double plated diamond and copper powder are mixed in a volume ratio of 3:7. The mixed sample is placed in a graphite cylindrical mold with an inner diameter of 13 mm. Vacuum is extracted, the heating rate is 100℃ / min, the pressure is 10MPa, the temperature is raised to 750℃, the pressure is increased to 50Mpa, and the temperature is raised to 950℃ at a rate of 200℃ / min for 1min, then the pressure is reduced to 10MPa at a rate of 60℃ / min, and the target product diamond copper composite material is obtained by natural cooling, and the thermal conductivity is 683W / mK.

[0079] Example 4

[0080] A method for preparing a high-thermal-conductivity diamond / copper composite material is provided, comprising the following steps:

[0081] S1: Pretreatment of diamond: same as example 1

[0082] S2: Magnetron sputtering of a tungsten layer on the diamond: same as example 1

[0083] S3: Heat treatment:

[0084] The magnetron sputtered diamond is subjected to high-temperature heat treatment in a tube furnace. The appropriate amount of tungsten plated diamond is placed in a corundum crucible and placed in the tube furnace. The furnace door is closed to ensure airtightness. A mechanical pump is used to extract vacuum, and argon is introduced to remove air to maintain an argon atmosphere in the furnace. This cycle is repeated three times. The temperature program is set to a heating rate of 10℃ / min. The tube furnace is protected by argon gas with a flow rate of 150mL / min. The temperature is 1100℃ and the holding time is 360min. After natural cooling, the sample is removed.

[0085] S4: Magnetron sputtering Cu layer: same as example 1

[0086] S5: Spark plasma sintering (SPS):

[0087] W / Cu double plated diamond and copper powder are mixed in a volume ratio of 3:7. The mixed sample is placed in a graphite cylindrical mold with an inner diameter of 13 mm. Vacuum is extracted, the temperature is raised at a rate of 100℃ / min, the pressure is 8MPa, the temperature is raised to 800℃, the pressure is increased to 45Mpa, and the temperature is raised to 950℃ at a rate of 150℃ / min for 1min, then the pressure is reduced to 8MPa at a rate of 50℃ / min after the temperature is reduced to 650℃, and then the target product diamond copper composite material is obtained by natural cooling, and the thermal conductivity is 666W / mK.

[0088] Comparative Example 1

[0089] A preparation method of a diamond composite material is provided, and the specific steps are the same as those of Example 1, except that S4 is omitted, i.e., the W plated diamond surface after heat treatment is no longer coated with a Cu layer by magnetron sputtering.

[0090] The diamond composite material obtained in the comparative example has a thermal conductivity of 531W / mK.

[0091] Comparative Example 2

[0092] A preparation method of a diamond composite material is provided, and the specific steps are the same as those of Example 1, except that S4 is omitted, i.e., the W plated diamond surface after heat treatment is no longer coated with a Cu layer by magnetron sputtering.

[0093] S1-S4 are the same as in Example 3.

[0094] S5: spark plasma sintering (SPS):

[0095] W / Cu double plated diamond and copper powder are mixed in a volume ratio of 3:7. The mixed sample is placed in a graphite cylindrical mold with an inner diameter of 13 mm. Vacuum is extracted, the temperature is raised at a rate of 100℃ / min, the pressure is 8MPa, the temperature is raised to 800℃, the pressure is increased to 45Mpa, and the temperature is raised to 950℃ at a rate of 150℃ / min for 1min, then the pressure is reduced to 8MPa at a rate of 50℃ / min after the temperature is reduced to 650℃, and then the target product diamond copper composite material is obtained by natural cooling, and the thermal conductivity is 666W / mK.

[0096] From the comparison between Example 3 and Comparative Example 2, it can be seen that the spark plasma sintering process has an important influence on the thermal conductivity performance of the prepared diamond copper composite material. In Comparative Example 2, pressure holding and heat preservation sintering causes copper to be plastic at high temperatures, and diamond displacement leads to diamond aggregation, and copper matrix is squeezed into the diamond gap, also forming a copper-rich area, which reduces the continuity of the thermal conduction path, and the performance of the diamond copper composite material after heat preservation sintering is reduced. In comparison, the diamond copper composite material prepared by the spark plasma sintering process of the present application has better performance.

[0097] Comparative Example 3

[0098] A preparation method of diamond composite material is provided, and the specific steps are the same as those in Example 2, except that in S5, the volume ratio of W / Cu double-coated diamond and copper powder is replaced by 4:6.

[0099] The thermal conductivity of the diamond composite material prepared in the present comparative example is 585 W / mK.

[0100] When the volume fraction of diamond reaches 40%, the density of diamond and copper composite material decreases, resulting in poor thermal conductivity performance of the composite material.

[0101] It should be understood that, for those skilled in the art, improvements or changes can be made according to the above description, and all these improvements and changes shall belong to the protection scope of the appended claims of the present application.

Claims

1. A method for preparing a high thermal conductivity diamond / copper composite material, characterized in that, Includes the following steps: 1) Etching treatment is performed on the diamond particles; 2) A sputtered tungsten layer is formed on the etched diamond surface obtained in step 1) by magnetron sputtering, followed by high-temperature treatment, and finally a copper layer is sputtered by magnetron sputtering; wherein, the high-temperature treatment process is: in an argon atmosphere, at 1100-1150℃ for 60-360 min. 3) Mix the copper-plated diamond particles obtained in step 2) with copper powder. The volume of the diamond particles is 30-35% of the total volume of the diamond particles and copper powder. Then, perform spark plasma sintering. The spark plasma sintering is as follows: the pre-pressure at the beginning of the heating stage is 8-10 MPa. Pressurization is applied in the last 50-70 seconds of the heating stage to a pressure of 44-55 MPa. After heating to the target sintering temperature of 750-950℃, the pressure is maintained for cooling annealing. After cooling to 500-650℃, the pressure is released to 8-10 MPa to obtain a high thermal conductivity diamond / copper composite material.

2. The preparation method according to claim 1, characterized in that, In step 1), the etching process is performed using a strong acid; the strong acid is aqua regia.

3. The preparation method according to claim 2, characterized in that, In step 1), etching the diamond with strong acid specifically involves roughening the diamond particles with strong acid for 30-60 minutes at a temperature of 40-60℃.

4. The preparation method according to claim 1, characterized in that, In step 2), the thickness of the sputtered tungsten layer is 60-80 nm; the thickness of the sputtered copper layer is 20-30 nm.

5. The preparation method according to claim 1, characterized in that, The initial heating rate is 75-100℃ / min; when pressurization begins, the heating rate is adjusted to 150-200℃ / min.

6. The preparation method according to claim 1, characterized in that, In step 3), the cooling rate during the cooling annealing stage is 30-60℃ / min.

7. A high thermal conductivity diamond / copper composite material prepared by the preparation method according to any one of claims 1-6.

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