Preparation method of high-thermal-conductivity insulating copper / diamond composite material

Abstract

The application discloses a preparation method of high-thermal-conductivity insulating copper / diamond composite material, and acid pickling roughening treatment is respectively conducted on artificial diamond sheets and diamond powder; a 100-500nm-thick metal titanium is prepared on surfaces of the diamond sheets and the diamond powder by adopting a vacuum micro-evaporation titanium plating process, so that plated titanium diamond sheets and plated titanium diamond powder are obtained; copper alloy powder and the plated titanium diamond powder with different volume ratios are mixed to obtain copper / diamond mixed materials, wherein diamond content is in gradient distribution, the highest content is 60vol%, and the lowest content is 0; resin mixed solutions are respectively added and stirred to uniformly mix, so that printing paste with gradient distribution of diamond content is obtained; the printing paste is sequentially printed on surfaces of the plated titanium diamond sheets by adopting silk screen printing, diamond content is from high to low, the content of the outermost layer is 0, and the printing paste is placed into a vacuum oven to be baked and solidified; after cooling, a copper / diamond preform is obtained; the obtained preform is placed into a vacuum hot-pressing furnace to be hot-pressed and sintered, and finally the high-thermal-conductivity insulating copper / diamond composite material is obtained.

Description

Technical Field

[0001] This invention belongs to the field of composite material technology, and specifically relates to a method for preparing a thermally conductive and insulating composite material. Background Technology

[0002] The continuous innovation of electronic information technology has driven power devices towards two extremes: ever-increasing output power while miniaturizing device size, resulting in a significant increase in heat flux density. How to effectively dissipate this high heat flux density has become a key technology in system design.

[0003] Diamond is a three-dimensional material with extremely high thermal conductivity. Its thermal conductivity is approximately isotropic in all directions, ranging from 1200 to 2000 W / mK, and its coefficient of thermal expansion is between 0.8 and 1.1 × 10⁻⁶. -6 / ℃, volume resistivity (25℃) > 10 15 Ω cm. Although composite materials such as diamond / copper and diamond / aluminum are new-generation thermal management materials with high thermal conductivity and suitable coefficient of thermal expansion, they cannot be used in applications requiring specific insulation or dielectric properties due to the presence of the metal matrix.

[0004] Currently, high thermal conductivity insulating materials mainly rely on the metallization of ceramic surfaces such as aluminum nitride and alumina. These materials possess both the insulation properties of ceramics and the thermal conductivity of metals, but their thermal conductivity is <400 W / mk. Patent CN 103187131 B describes a high thermal conductivity insulating composite material and its preparation method. This material consists of a high thermal conductivity composite material and an insulating layer deposited on it. This method uses chemical vapor deposition to prepare the insulating layer, achieving a thermal conductivity >400 W / mk. However, the low deposition efficiency and cumbersome preparation process severely limit production efficiency.

[0005] In view of this, a low-cost, high-strength, high-thermal-conductivity (thermal conductivity > 600 W / Mk) insulating copper / diamond composite material and its preparation method have become urgent technical problems to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing a high thermal conductivity and insulating copper / diamond composite material. The middle sandwich layer is a certain thickness of high thermal conductivity and insulating artificial sheet diamond, and the upper and lower layers are copper / diamond composite layers with gradient distribution. After hot pressing and sintering, a low-cost, high-strength, high thermal conductivity and insulating copper / diamond composite material is obtained.

[0007] To achieve the above objectives, the following technical solution is adopted:

[0008] A method for preparing a high thermal conductivity and insulating copper / diamond composite material includes the following steps:

[0009] (1) The artificial diamond sheet and diamond powder were respectively acid-washed and roughened;

[0010] (2) A titanium metal with a thickness of 100-500 nm was prepared on the surface of diamond sheet and diamond powder respectively by vacuum micro-evaporation titanium plating process to obtain titanium-plated diamond sheet and titanium-plated diamond powder.

[0011] (3) Copper alloy powder and titanium-plated diamond powder with different volume ratios are mixed to obtain copper / diamond mixture, wherein the diamond content is distributed in a gradient, with the highest being 60vt% and the lowest being 0vt%. The mixture is added to the resin mixture solution and stirred to obtain printing paste with a gradient diamond content.

[0012] (4) A printing paste with a gradient diamond content is sequentially printed onto the surface of the titanium-plated diamond sheet obtained in step (2) by screen printing. The diamond content is from high to low, and the content of the outermost layer is 0. The sheet is placed in a vacuum oven for baking and curing. After cooling, a copper / diamond preform is obtained.

[0013] (5) The obtained preforms are placed in a vacuum hot press furnace for hot pressing and sintering to finally obtain a high thermal conductivity insulating copper / diamond composite material.

[0014] According to the above scheme, the diamond sheet mentioned in step 1 has a thermal conductivity of 1000-1500 W / mK, a thickness of 0.2-0.5 mm, and a volume resistivity (25℃) > 10. 15 Ω㎝.

[0015] According to the above scheme, the diamond powder particle size in step 1 is 50-100um, preferably 50-75um.

[0016] According to the above scheme, step 2, the vacuum micro-evaporation titanium plating process, includes the following steps:

[0017] Diamond sheets and diamond powder are placed in a special crucible of a vacuum micro-evaporation coating machine, with a vacuum degree greater than 5*10. -4 After Pa, the temperature is increased to 700-800℃ and held for 60-90 minutes. After the coating is completed, it is kept under vacuum and cooled to room temperature to obtain titanium-coated diamond sheets and titanium-coated diamond powder.

[0018] According to the above scheme, the resin mixture solution in step 3 is prepared by mixing saturated polyester resin, dibasic acid ester organic solvent, and isocyanate curing agent in a mass ratio of (4-6):(4-5):(0.5-1).

[0019] According to the above scheme, the copper alloy powder in step 3 is prepared by a water-air combined atomization powder preparation process, with a particle size of 10-100 μm, preferably 20-50 μm; its composition mass fraction is: B: 0.06-0.8%, P: 0.002-0.2%, Cr: 0.02-0.5%, Al: 0.01-0.2%, and the balance is Cu.

[0020] According to the above scheme, step 3 includes putting titanium-plated diamond powder and copper alloy powder into a mixer to prepare four different volume fraction copper / diamond mixtures with diamond volume fractions of 60%, 40%, 20%, and 0%.

[0021] According to the above scheme, in step 3, the copper / diamond mixture and the resin mixture solution are mixed at a mass ratio of 2:(1~1.5).

[0022] According to the above scheme, in step 4, printing pastes with diamond content from high to low are sequentially stacked and printed onto the surface of the titanium-plated diamond sheet, with each layer having a printing thickness of 0.1 to 0.2 mm.

[0023] According to the above scheme, the hot pressing sintering process conditions in step 5 include:

[0024] Vacuum degree of 10 -1 ~10 -2 Pa, in an inert atmosphere or a hydrogen-argon mixed reducing atmosphere with a hydrogen gas fraction of 5%, the temperature is heated to 900-1050℃ at a rate of 5-20℃ / min and held for 30-120min. After the holding period, the pressure is increased to 1-5MPa for 30-120min.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] Synthetic diamond possesses high thermal conductivity and insulation, but its high surface energy and significantly different coefficient of thermal expansion compared to other materials make high-strength composites difficult to achieve. This invention addresses this by roughening the surfaces of synthetic diamond and diamond powder to increase the diamond's surface area. Simultaneously, a protective layer of metallic titanium is prepared using vacuum evaporation deposition technology. Titanium is a highly reactive metal that readily forms various intermetallic compounds such as Ti₂Cu and TiCu with copper. Studies have shown that a thick metal film on the diamond surface can hinder the overall thermal conductivity of the diamond-metal composite. However, the vacuum micro-evaporation deposition process can effectively control the growth rate of the metal film, allowing metallic titanium to uniformly coat the surface of the synthetic diamond sheet or diamond powder. This invention solves both the diamond surface energy problem and the overall thermal resistance of the titanium film to the copper / diamond structure.

[0027] This invention employs a core layer of synthetic diamond sheet and an upper and lower layer of gradient-distributed copper / diamond structure. The synthetic diamond sheet effectively separates the upper and lower copper / diamond layers, providing excellent thermal conductivity and insulation. This invention, by preparing a copper / diamond gradient on the surface of the synthetic diamond sheet, solves the problems of interface cracking and poor thermal conductivity caused by the large difference in thermal expansion coefficients between the synthetic diamond sheet and copper / diamond.

[0028] The copper alloy powder designed in this invention incorporates trace amounts of boron (B) and phosphorus (P). On one hand, during sintering, trace amounts of oxygen oxidize the copper powder to form CuO2, while B and P act as deoxidizers, reducing CuO2 to Cu and simultaneously generating oxides of B and P, which are then expelled from the furnace, thus improving the performance of the copper-diamond alloy. On the other hand, Cr and Al elements dissolve into the Cu matrix, increasing its strength. Simultaneously, Cr and Al expand to the diamond surface, forming multi-element solid solutions with Ti and Cu, enhancing the bonding strength between the copper alloy framework and the diamond, and improving thermal conductivity.

[0029] This invention employs high-temperature pressure sintering. Since an oxide film easily forms on the surface of copper alloy powder during high-temperature sintering, hindering sintering, applying an external force during the sintering process can break the oxide film and improve the density of copper / diamond.

[0030] Diamond particles have a high hardness, reaching 10 on the Mohs scale, making them difficult to process. The outermost layer of this invention's high thermal conductivity insulating copper / diamond composite material has zero diamond content, ensuring surface machinability and achieving a surface roughness Ra ≤ 0.2.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention provides a high thermal conductivity and insulating copper / diamond composite material and its preparation method. The composite material uses a synthetic diamond sheet as a sandwich layer with copper / diamond materials distributed in a gradient on both sides, and is coated with a certain thickness of copper. It possesses advantages such as high strength, high thermal conductivity (thermal conductivity > 600 W / mk), low thermal expansion, and high insulation. Furthermore, both the upper and lower surfaces can be machined, making it suitable for manufacturing high-precision, high thermal conductivity and insulating parts requiring a high degree of surface finish.

[0033] The preparation process provided by this invention is simple and suitable for large-scale industrial production. Attached Figure Description

[0034] Figure 1 : Flowchart of the preparation process of the high thermal conductivity insulating copper / diamond composite material of this invention.

[0035] Figure 2 Morphology and energy dispersive spectroscopy of titanium-plated diamond powder in Case Study 1.

[0036] Figure 3 : Schematic diagram of the high thermal conductivity insulating copper / diamond composite material structure of this invention. Detailed Implementation

[0037] The following embodiments further illustrate the technical solution of the present invention, but are not intended to limit the scope of protection of the present invention.

[0038] A specific embodiment provides a method for preparing a high thermal conductivity and insulating copper / diamond composite material, the process flow of which is shown in the appendix. Figure 1 As shown:

[0039] (1) The artificial diamond sheet and diamond powder were acid-washed and roughened respectively; including first soaking the artificial diamond sheet and diamond powder in 150g / L NaOH solution for 30min to remove grease, then washing with water until neutral; then soaking in 80% (concentrated nitric acid to water volume ratio of 4:1) HNO3 solution for 40min to roughen, then washing with water until neutral and drying.

[0040] (2) A titanium metal with a thickness of 100-500 nm was prepared on the surface of diamond sheet and diamond powder respectively by vacuum micro-evaporation titanium plating process to obtain titanium-plated diamond sheet and titanium-plated diamond powder.

[0041] (3) Copper alloy powder and titanium-plated diamond powder with different volume ratios are mixed to obtain copper / diamond mixture, wherein the diamond content is distributed in a gradient, with the highest being 60vt% and the lowest being 0vt%. The mixture is added to the resin mixture solution and stirred to obtain printing paste with a gradient diamond content.

[0042] (4) A printing paste with a gradient diamond content is sequentially printed onto the surface of the titanium-plated diamond sheet obtained in step (2) by screen printing. The diamond content is from high to low, and the content of the outermost layer is 0. The sheet is placed in a vacuum oven for baking and curing. After cooling, a copper / diamond preform is obtained.

[0043] (5) The obtained preforms are placed in a vacuum hot press furnace for hot pressing and sintering to finally obtain a high thermal conductivity insulating copper / diamond composite material.

[0044] Specifically, diamond sheets with a thermal conductivity of 1000–1500 W / mK, a thickness of 0.2–0.5 mm, and a volume resistivity (25℃) > 10⁻⁶ are used. 15 Ω cm. The diamond powder used has a particle size of 50-100 μm, preferably 50-75 μm.

[0045] Specifically, step 2, the vacuum micro-evaporation titanium plating process, includes the following steps:

[0046] Diamond sheets and diamond powder are placed in a special crucible of a vacuum micro-evaporation coating machine, with a vacuum degree greater than 5*10. -4After Pa, the temperature is increased to 700-800℃ and held for 60-90 minutes. After the coating is completed, it is kept under vacuum and cooled to room temperature to obtain titanium-coated diamond sheets and titanium-coated diamond powder.

[0047] Specifically, the resin mixture in step 3 is prepared by mixing saturated polyester resin, dibasic acid ester organic solvent, and isocyanate curing agent in a mass ratio of (4-6):(4-5):(0.5-1).

[0048] Specifically, the copper alloy powder is prepared by a water-air combined atomization powder preparation process, with a particle size of 10-100 μm, preferably 20-50 μm; its composition by mass fraction is: B: 0.06-0.8%, P: 0.002-0.2%, Cr: 0.02-0.5%, Al: 0.01-0.2%, and the balance is Cu.

[0049] Specifically, step 3 involves placing titanium-plated diamond powder and copper alloy powder into a mixer to prepare four different volume fraction copper / diamond mixtures with diamond volume fractions of 60%, 40%, 20%, and 0%. The copper / diamond mixtures are then mixed with the resin mixture solution at a mass ratio of 2:(1-1.5).

[0050] Specifically, in step 4, printing pastes with diamond content from high to low are stacked and printed sequentially onto the surface of the titanium-plated diamond sheet, with each layer having a printing thickness of 0.1 to 0.2 mm.

[0051] Specifically, the hot pressing sintering process conditions in step 5 include:

[0052] Vacuum degree of 10 -1 ~10 -2 Pa, in an inert atmosphere or a hydrogen-argon mixed reducing atmosphere with a hydrogen gas fraction of 5%, the temperature is heated to 900-1050℃ at a rate of 5-20℃ / min and held for 30-120min. After the holding period, the pressure is increased to 1-5MPa for 30-120min.

[0053] Example 1

[0054] 1) Vacuum micro-evaporation titanium plating treatment of synthetic diamond sheets and diamond powder: First, soak the synthetic diamond sheets and diamond powder in 150g / L NaOH solution for 30min to remove grease, then wash with water until neutral; then soak in 80% (concentrated nitric acid to water volume ratio of 4:1) HNO3 solution for 40min to remove grease, then wash with water until neutral and dry; place the diamond sheets and diamond powder in a special crucible of a vacuum micro-evaporation coating machine, with a vacuum degree greater than 5*10 -4After Pa, the temperature is increased to 750℃ and held for 60 minutes. After coating, the product is cooled to room temperature under vacuum. The product is then removed, yielding titanium-coated diamond sheets and titanium-coated diamond powder. The diamond particle size is 50µm. The synthetic diamond sheet has a thermal conductivity of 1250W / mK, a thickness of 0.3mm, and a volume resistivity (25℃) of 6.8*10⁻⁶. 15 Ω cm. Morphology and energy dispersive spectroscopy of titanium-plated diamond powder are shown in [reference needed]. Figure 2 As shown.

[0055] 2) Polyester resin, dibasic acid ester organic solvent, and isocyanate curing agent were thoroughly mixed at a mass ratio of 4:4:0.5 to obtain a resin mixture solution. Four copper / diamond mixtures with diamond volume fractions of 60%, 40%, 20%, and 0% were added to the resin mixture solution and stirred until homogeneous to obtain copper / diamond printing paste. The copper alloy powder was a pre-alloyed powder prepared by a water-air combined atomization powdering process, with a particle size of 40–50 μm. Its composition by mass fraction was: B: 0.1%, P: 0.005%, Cr: 0.05%, Al: 0.03%, Cu: balance.

[0056] 3) Four types of copper / diamond printing pastes were sequentially stacked and printed onto the surface of a titanium-plated diamond sheet. Each layer was 0.1 mm thick, with a gradient distribution of diamond content, and the surface layer had zero diamond content. The sheet was then placed in a vacuum oven and baked at 120°C for 30 minutes. After cooling, an insulating copper / diamond preform was obtained.

[0057] 4) The obtained preforms are placed in a vacuum hot press furnace for hot pressing and sintering. The process conditions are: vacuum degree of 10 -1 A hydrogen-argon mixed reducing atmosphere with a hydrogen gas integral of 5% was used. The atmosphere was heated to 1000℃ at a rate of 6℃ / min and held for 60min. After the holding period, the atmosphere was pressurized to 3MPa for 30min.

[0058] The high thermal conductivity insulating copper / diamond composite material obtained in this embodiment has a bonding strength of 75 MPa between the copper diamond and the synthetic diamond sheet, a comprehensive thermal conductivity of 782 W / mk, and a coefficient of thermal expansion of 7.6 × 10⁻⁶. -6 / ℃, Volume resistivity (25℃) 5.3*10 15 Ω㎝.

[0059] A schematic diagram of the high thermal conductivity and insulating copper / diamond composite material structure obtained in this embodiment is attached. Figure 3 As shown.

[0060] Example 2

[0061] 1) Vacuum micro-evaporation titanium plating treatment of synthetic diamond sheets and diamond powder: First, soak the synthetic diamond sheets and diamond powder in 150g / L NaOH solution for 30min to remove grease, then wash with water until neutral; then soak in 80% (concentrated nitric acid to water volume ratio of 4:1) HNO3 solution for 40min to remove grease, then wash with water until neutral and dry; place the diamond sheets and diamond powder in a special crucible of a vacuum micro-evaporation coating machine, with a vacuum degree greater than 5*10 -4 After Pa, the temperature is increased to 750℃ and held for 60 minutes. After coating, the product is cooled to room temperature under vacuum. The product is then removed, yielding titanium-coated diamond sheets and titanium-coated diamond powder. The diamond particle size is 100µm. The synthetic diamond sheet has a thermal conductivity of 1250W / mK, a thickness of 0.3mm, and a volume resistivity (25℃) of 6.8*10⁻⁶. 15 Ω㎝.

[0062] 2) Polyester resin, dibasic acid ester organic solvent, and isocyanate curing agent were thoroughly mixed at a mass ratio of 4:5:0.8 to obtain a resin mixture solution. Four copper / diamond mixtures with diamond volume fractions of 60%, 40%, 20%, and 0% were added to the resin mixture solution and stirred until homogeneous to obtain copper / diamond printing paste. The copper alloy powder was a pre-alloyed powder prepared by a water-air combined atomization powdering process, with a particle size of 40–50 μm. Its composition by mass fraction was: B: 0.5%, P: 0.1%, Cr: 0.3%, Al: 0.2%, Cu: balance.

[0063] 3) Four types of copper / diamond printing pastes were sequentially stacked and printed onto the surface of a titanium-plated diamond sheet. Each layer was 0.2 mm thick, with a gradient distribution of diamond content, and the surface layer had zero diamond content. The sheet was then placed in a vacuum oven and baked at 120°C for 30 minutes. After cooling, an insulating copper / diamond preform was obtained.

[0064] 4) The obtained preforms are placed in a vacuum hot press furnace for hot pressing and sintering. The process conditions are: vacuum degree of 10 -1 A hydrogen-argon mixed reducing atmosphere with a hydrogen gas integral of 5% was used. The atmosphere was heated to 950°C at a rate of 6°C / min and held for 60 min. After the holding period, the atmosphere was pressurized to 1 MPa for 30 min.

[0065] The high thermal conductivity insulating copper / diamond composite material obtained in this embodiment has the following bonding strengths to the synthetic diamond sheet: 58 MPa, overall thermal conductivity: 695 W / mk, and overall coefficient of thermal expansion: 7.2 × 10⁻⁶. -6 / ℃, Volume resistivity: (25℃) 4.1*10 15 Ω㎝.

[0066] Comparative Example 1

[0067] The volume fraction of diamond in the copper / diamond mixture in Example 1 was changed, and the experimental results are shown in Table 1.

[0068] Table 1

[0069]

[0070]

[0071] Comparative Example 2

[0072] The high-temperature pressure sintering parameters in Example 1 were changed, and the experimental results are shown in Table 2.

[0073] Table 2

[0074] Comparative experiment temperature pressure result 1 800℃ 10 MPa Synthetic diamond sheet cracking 2 1000℃ 3Mpa The bond strength between copper diamond and diamond sheet is 5 MPa, and the thermal conductivity is 320 W / mK. 3 1050℃ 3Mpa The bonding strength between copper diamond and diamond sheet is 75 MPa, and the overall thermal conductivity is 782 W / m. 4 800℃ 3Mpa The bond strength between copper diamond and diamond sheet is 2 MPa, and the overall thermal conductivity is 282 W / m. 5 1050℃ 1Mpa The bond strength between copper diamond and diamond sheet is 43 MPa, and the overall thermal conductivity is 565 W / m.

[0075] The above comparison shows that different surface diamond volume fractions, excessively high or low sintering temperatures, and sintering pressure and time all affect product performance.

Claims

1. A method for preparing a high thermal conductivity and insulating copper / diamond composite material, characterized in that... Includes the following steps: (1) The artificial diamond sheet and diamond powder were respectively acid-washed and roughened; (2) Using a vacuum micro-evaporation titanium plating process, metallic titanium with a thickness of 100~500nm was prepared on the surface of artificial diamond sheets and diamond powder respectively, to obtain titanium-plated diamond sheets and titanium-plated diamond powder. (3) Copper alloy powder and titanium-plated diamond powder with different volume ratios are mixed to obtain copper / diamond mixture, wherein the diamond content is distributed in a gradient, with the highest being 60 vt% and the lowest being 0; respectively, they are added to the resin mixture solution and stirred to obtain printing paste with diamond content distributed in a gradient. (4) The printing paste obtained in step (3) is printed sequentially on the surface of the titanium-plated diamond sheet obtained in step (2) by screen printing. The diamond content is from high to low, and the content of the outermost layer is 0. The sheet is placed in a vacuum oven for baking and curing. After cooling, a copper / diamond preform is obtained. (5) The obtained preforms are placed in a vacuum hot press furnace for hot pressing and sintering to finally obtain a high thermal conductivity insulating copper / diamond composite material.

2. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... The synthetic diamond sheet described in step 1 has a thermal conductivity of 1000~1500 W / mK, a thickness of 0.2~0.5 mm, and a volume resistivity >10 at 25℃. 15 Ω·cm.

3. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... The diamond powder particles mentioned in step 1 have a particle size of 50~100μm.

4. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... Step 2, the vacuum micro-evaporation titanium plating process, includes the following steps: Artificial diamond sheets and diamond powder are placed in a special crucible of a vacuum micro-evaporation coating machine, with a vacuum degree greater than 5*10. - 4 After Pa, the temperature is increased to 700-800℃ and held for 60-90 minutes. After the coating is completed, it is kept under vacuum and cooled to room temperature to obtain titanium-coated diamond sheets and titanium-coated diamond powder.

5. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... The resin mixture solution described in step 3 is prepared by mixing saturated polyester resin, dibasic acid ester organic solvent, and isocyanate curing agent in a mass ratio of (4~6):(4~5):(0.5~1).

6. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... In step 3, the copper alloy powder was prepared by a water-air combined atomization powder preparation process, and the particle size was 10~100μm. Its composition by mass fraction is: B: 0.06~0.8%, P: 0.002~0.2%, Cr: 0.02~0.5%, Al: 0.01~0.2%, with the balance being Cu.

7. The preparation method of the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... Step 3 involves placing titanium-plated diamond powder and copper alloy powder into a mixer to prepare four different volume fraction copper / diamond mixtures with diamond volume fractions of 60%, 40%, 20%, and 0%.

8. The method for preparing the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... In step 3, the copper / diamond mixture and the resin mixture are mixed at a mass ratio of 2:(1~1.5).

9. The method for preparing the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... Step 4: Print the printing paste with diamond content from high to low sequentially onto the surface of the titanium-plated diamond sheet, with each layer having a printing thickness of 0.1~0.2mm.

10. The method for preparing the high thermal conductivity insulating copper / diamond composite material as described in claim 1, characterized in that... Step 5, the hot pressing sintering process conditions, include: Vacuum degree of 10 -1 ~10 -2 Pa, in an inert atmosphere or a hydrogen-argon mixed reducing atmosphere with a hydrogen gas fraction of 5%, heat to 900-1050℃ at a rate of 5-20℃ / min, hold for 30-120min, pressurize after holding for 1-5MPa for 30-120min.

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