A method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material

Abstract

The present invention discloses a method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material, comprising the following specific steps: surface cleaning and drying of porous copper with a three-dimensional structure, in-situ growth of graphene on the porous copper surface by chemical vapor deposition, applying plasma to the porous copper surface during the growth process so that the graphene growth direction is parallel to the porous copper surface; filling the porous copper with graphene with carbide-plated diamond particles to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform; the preform is placed in a hot isostatic press or a six-sided top press, and the preform is applied and pressure-maintained at low temperature or room temperature, and the preform is hot-pressed and sintered, and after heat preservation and pressure maintenance, the temperature is lowered to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material; and heat treatment is performed. The present invention can construct a continuous graphene network structure in the composite material, break the "island" effect, and provide a high thermal conductivity channel for the composite material.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material. Background Art

[0002] With the development of integration technology and microelectronic packaging technology, the "high performance and high integration" of semiconductor devices and chips have led to a continuous increase in power density. High thermal conductivity electronic packaging heat dissipation materials have become a guarantee for solving the problem of efficient heat dissipation of devices and their reliability development. Electronic packaging heat dissipation materials have gone through multiple generations of development, such as Invar and Kovar alloys, Cu / W and Cu / Mo alloys, and Al / SiC and Cu / Si metal-based composite materials. The thermal conductivity is lower than 300 W / mK, which is difficult to meet the heat dissipation requirements of high-power devices. In recent years, diamond / copper composite materials prepared by combining diamond particles with high thermal conductivity (1800-2000 W / mK) and low thermal expansion coefficient (1.0 ppm / K) as reinforcement and copper matrix have been well matched with various levels of packaging materials due to their high thermal conductivity and flexible regulation of thermal expansion coefficient, making them ideal packaging materials for microwave solid-state power amplifiers in modern satellite communications, radars and electronic warfare fields.

[0003] Diamond / copper composite materials are a research hotspot for the new generation of electronic packaging materials, but the main research ideas at home and abroad are to improve the interface between diamond particles and copper by alloy matrix and surface modification of diamond particles. Although good results have been achieved, it is difficult to form a connected heat conduction channel in this composite structure due to the presence of copper matrix between diamond particles. There are not only a large number of interfaces between the two phases, but also it is difficult to produce synergy, making it difficult for diamond to fully exert its excellent thermal conductivity. Patent CN109825815B proposes a preparation method for reducing the interface thermal resistance of diamond / copper thermal conductive composite materials, in which the interface thermal resistance is reduced by in-situ growth of graphene on the surface of diamond particles, but it is difficult to form a three-dimensional connected structure, eliminate the influence of interface thermal resistance and make the two phases produce synergy. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material in view of the deficiencies of the above-mentioned prior art, to construct a continuous graphene network structure in the composite material, to break the "island" effect, and to provide a high thermal conductivity channel for the composite material.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material comprises the following specific steps:

[0007] Step 1: Clean and dry the surface of the porous copper with a three-dimensional structure, grow graphene in situ on the surface of the porous copper by chemical vapor deposition, and apply plasma to the surface of the porous copper during the growth of the graphene to promote the growth direction of the graphene to be parallel to the porous copper surface;

[0008] Step 2: Filling the porous copper with graphene grown with carbide-coated diamond particles to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0009] Step 3: placing the composite material preform in a hot isostatic press or a six-sided top press, first applying and maintaining pressure on the preform at low temperature or room temperature, then hot pressing and sintering the preform, and after heat preservation and pressure maintenance, cooling to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material;

[0010] Step 4: heat-treating the three-dimensional interconnected graphene-diamond reinforced copper-based composite material to complete the preparation.

[0011] To optimize the above technical solutions, the specific measures taken also include:

[0012] In the above step 1, the pore size of the porous copper is 10 μm-10 mm, and the porosity is 40-90%.

[0013] In the above step 1, the parameters of the chemical vapor deposition are: the carbon-containing gas accounts for 5-70% of the mass flow rate of the total gas in the furnace.

[0014] In the above step 1, the growth temperature of the growth process is 800-1200 ° C, and the growth pressure is 10 3 -10 5 Pa, plasma current density is 10-40 mA / cm 2 .

[0015] In the above step 2, the particle size of the diamond particles is 50-900 μm, and the size of the diamond particles is always smaller than the aperture of the porous copper holes in which the graphene is grown.

[0016] In the above step 2, the carbide is WC, MoC, Cr 7 C 3 、TiC、B 4 C, SiC, ZrC, NbC and VC.

[0017] In the above step 3, if a hot isostatic press is used to apply and hold pressure on the preform, the applied pressure is 100-150 MPa, the heating rate is 5-15 min / °C, the holding time is 0.5-24 h, and the temperature is 20-500°C;

[0018] If a six-sided top press is used to apply and maintain pressure on the preform, the applied pressure is 2-4 GPa, the pressure-maintaining time is 0.5-24 h, and the temperature is 20-500 °C.

[0019] In the above step three, the sintering temperature of the hot pressing sintering is 800~1100°C, the sintering pressure when using a hot isostatic press is 100~200 MPa, the sintering pressure when using a six-sided top press is 4~8 GPa, and the holding time after hot pressing sintering is 10~30 min.

[0020] In the above step 4, the heat treatment temperature is 200-400°C and the time is 10-120 min.

[0021] The present invention has the following beneficial effects:

[0022] 1. The present invention firstly grows graphene laterally on the surface of a porous copper substrate by chemical vapor deposition, and then combines it with diamond particles. The porous copper on which the graphene is grown is filled with diamond particles to form a composite material preform. The diamond particles and the copper substrate are three-dimensionally connected using graphene as a "bond", and a three-dimensional connected heat conduction channel is formed, which weakens the interfacial thermal resistance between the two phases, exerts a synergistic effect, and greatly improves the thermal conductivity of the diamond / copper composite material.

[0023] 2. Different from the pressure infiltration method for preparing diamond / copper composite materials, the present invention uses a hot isostatic press / six-sided top press to perform low-temperature pressurization and high-temperature sintering on the preform to form a graphene-diamond reinforced copper-based composite material. The composite material is prepared below the melting point of copper, which effectively avoids the destruction of the three-dimensional connected graphene structure by the molten copper liquid, maintains the connectivity between the reinforcement phase and the matrix in three-dimensional space, and greatly weakens the influence of the composite interface on the thermal properties of the material, so that the composite material has excellent continuous thermal conductivity, fundamentally solving the problem that the thermal conductivity of the composite material is difficult to further improve.

[0024] 3. The present invention finally performs heat treatment on the composite material to eliminate the interface thermal stress and obtain a graphene-diamond reinforced copper-based composite material with high thermal conductivity.

[0025] 4. The present invention is simple to operate, highly feasible, suitable for large-scale production, and beneficial to improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Fig. 1 is a flow chart of the method of the present invention;

[0027] Figure 2 The schematic diagram of the method of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Although the steps in the present invention are arranged with numbers, they are not used to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a certain step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" used in this article involves and covers any and all possible combinations of one or more of the associated listed items.

[0030] like Figure 1-2 As shown, a method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material of the present invention comprises the following specific steps:

[0031] Step 1: Clean and dry the surface of the porous copper, and in-situ grow graphene of a certain thickness on the surface of the porous copper by chemical vapor deposition, and apply plasma to the surface of the graphene during the growth process to make the growth direction of the graphene parallel to the surface of the porous copper;

[0032] Step 2: Filling the porous copper on which the graphene is grown in step 1 with carbide-plated diamond particles smaller than the pore size of the porous copper to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0033] Step 3: placing the composite material preform in step 2 in a hot isostatic press / six-sided top press, first applying pressure to the composite material at low temperature or room temperature and maintaining the pressure for a period of time to densify the preform, then heating the equipment to the sintering temperature, maintaining the temperature and pressure for a period of time, and then cooling down to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material;

[0034] Step 4: heat-treating the three-dimensional interconnected graphene-diamond reinforced copper-based composite material prepared in step 3.

[0035] In the embodiment, in step 1, the pore size of the porous copper is 10 μm-10 mm, the porosity is 40-90%, and it is a three-dimensional structure.

[0036] The chemical vapor deposition parameters are: the carbon-containing gas accounts for 5-70% of the total gas mass flow in the furnace; the growth temperature is 800-1200 ° C, the growth pressure is 10 3 -10 5 Pa;

[0037] Plasma current density is 10-40 mA / cm 2 .

[0038] In the embodiment, in step 2, the particle size of the diamond is 50-900 μm, and the size of the diamond particles is always smaller than the diameter of the porous copper holes where the graphene is grown.

[0039] The carbides on the diamond surface are WC, MoC, Cr 7 C 3 、TiC、B 4 C, SiC, ZrC, NbC and VC.

[0040] In the embodiment, in step 3, the applied pressure of the hot isostatic press at low temperature or room temperature is 100-150 MPa, the heating rate is 5-15 min / °C, the holding time is 0.5-24 h, and the temperature is 20-500°C. The applied pressure of the six-sided top press at low temperature or room temperature is 2-4 GPa, the holding time is 0.5-24 h, and the temperature is 20-500°C.

[0041] The purpose of applying pressure to the composite material at low temperature or room temperature and maintaining the pressure for a period of time is, on the one hand, to make the graphene contact with the coated diamond to form a copper-graphene-carbide-diamond interface, and on the other hand, to densify the graphene-diamond reinforced copper-based composite material.

[0042] The sintering temperature of the composite material is 800-1100°C, the sintering pressure of the hot isostatic press is 100-200 MPa, the sintering pressure of the six-sided top press is 4-8 GPa, and the holding time is 10-30 min.

[0043] In the embodiment, in step 4, the composite material is heat treated at a temperature of 200-400°C for a time of 10-120 minutes. The purpose of heat treatment of the composite material is to eliminate interface thermal stress and strengthen interface bonding strength. Example 1

[0044] This embodiment includes the following steps:

[0045] Step 1: Clean and dry the porous copper with a pore diameter of 100 μm and a porosity of 60%. The chemical vapor deposition parameters are as follows: the carbon-containing gas accounts for 50% of the total gas mass flow rate in the furnace; the growth temperature is 800 °C, and the growth pressure is 10 5 The Pa deposition system in situ grows graphene with a thickness of 20 μm on the porous copper surface. During the graphene growth process, a plasma current density of 40 mA / cm is applied to the surface. 2 The plasma causes the graphene to grow parallel to the porous copper surface.

[0046] Step 2: Then, the porous copper on which the graphene is grown is filled with titanium carbide-coated diamond particles with a pore size of 57 μm to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0047] Step 3: Place the composite material preform in a hot isostatic press, first apply a 2 GPa pressure to the composite material at room temperature and hold the pressure for 30 minutes to densify the preform, then heat the equipment to 950 ° C, apply a 150 MPa pressure for 10 minutes, then cool to room temperature and take out the composite material;

[0048] Step 4: Further heat treat the composite material at 200 °C for 20 min to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material.

[0049] The thermal conductivity of the composite material prepared in this example is 836 W / mK. Example 2

[0050] This embodiment includes the following steps:

[0051] Step 1: Clean and dry the porous copper with a pore diameter of 1000 μm and a porosity of 73%. The chemical vapor deposition parameters are as follows: the carbon-containing gas accounts for 60% of the total gas mass flow rate in the furnace; the growth temperature is 800 °C, and the growth pressure is 10 5 The Pa deposition system in situ grows graphene with a thickness of 20 μm on the porous copper surface. During the graphene growth process, a plasma current density of 30 mA / cm is applied to the surface. 2 The plasma causes the graphene to grow parallel to the porous copper surface.

[0052] Step 2: Then, the porous copper on which the graphene is grown is filled with titanium carbide-coated diamond particles with a pore size of 301 μm to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0053] Step 3: Place the composite material preform in a six-sided top press, first apply a 3 GPa pressure to the composite material at room temperature and hold the pressure for 40 minutes to densify the preform, then heat the equipment to 900 ° C, apply a 6 GPa pressure and hold the pressure for 10 minutes, then cool to room temperature and take out the composite material;

[0054] Step 4: Further heat treat the composite material at 350 °C for 10 min to obtain a three-dimensional connected graphene-diamond reinforced copper-based composite material.

[0055] The thermal conductivity of the composite material prepared in this example is 747 W / mK. Comparative Example 1

[0056] This comparative example comprises the following steps:

[0057] The porous copper with a pore diameter of 100 μm and a porosity of 60% was cleaned and dried, and the growing porous copper was filled with titanium carbide-coated diamond particles with a pore diameter of 57 μm to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0058] The composite material preform is placed in a hot isostatic press, and firstly a pressure of 100 MPa is applied to the composite material at room temperature and the pressure is maintained for 30 minutes to densify the preform, and then the equipment is heated to 950 ° C, a pressure of 150 MPa is applied and the pressure is maintained for 10 minutes, and then the temperature is cooled to room temperature, and the composite material is taken out;

[0059] The composite material was further heat treated at 200 °C for 20 min to obtain a three-dimensional connected graphene-diamond reinforced copper-based composite material.

[0060] The thermal conductivity of the composite material prepared in this comparative example is 513 W / mK. Example 3

[0061] This embodiment includes the following steps:

[0062] Step 1: Clean and dry the porous copper with a pore diameter of 10 mm and a porosity of 40%. The chemical vapor deposition parameters are as follows: the carbon-containing gas accounts for 42% of the total gas mass flow rate in the furnace; the growth temperature is 1000 °C, and the growth pressure is 10 5 The Pa deposition system in situ grows graphene with a thickness of 20 μm on the porous copper surface. During the graphene growth process, a plasma current density of 20 mA / cm is applied to the surface. 2 The plasma causes the graphene to grow parallel to the porous copper surface.

[0063] Step 2: Then, the porous copper on which the graphene is grown is filled with titanium carbide-coated diamond particles with a pore size of 851 μm to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform;

[0064] Step 3: Place the composite material preform in a six-sided top press, first apply a 4 GPa pressure to the composite material at room temperature and hold the pressure for 50 minutes to densify the preform, then heat the equipment to 1000 °C, apply a 8 GPa pressure and hold the pressure for 10 minutes, then cool to room temperature and take out the composite material;

[0065] Step 4: Further heat treat the composite material at 200 °C for 30 min to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material.

[0066] The thermal conductivity of the composite material prepared in this example is 689 W / mK.

[0067] Based on the above three embodiments and a comparative example, it can be seen that as the pressure applied to the preform and the holding time increase, the preform can be densified, thereby improving the thermal conductivity of the composite material. However, when the pressure exceeds 2GPa and the holding time exceeds 40min, the thermal conductivity of the composite material shows a downward trend. This shows that the equipment pressure and holding time should be reasonably controlled.

[0068] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0069] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material, characterized in that: The specific steps include: Step 1: Clean and dry the surface of the porous copper with a three-dimensional structure, grow graphene in situ on the surface of the porous copper by chemical vapor deposition, and apply plasma to the surface of the porous copper during the growth of the graphene to promote the growth direction of the graphene to be parallel to the porous copper surface; Step 2: Filling the porous copper with graphene grown with carbide-coated diamond particles to form a three-dimensional interconnected graphene-diamond reinforced copper-based composite material preform; Step 3, the composite material preform is placed in a six-sided top press, firstly, the preform is applied and maintained at a temperature of 20-500 ° C, and then the preform is hot-pressed and sintered, and after heat preservation and pressure maintenance, the temperature is lowered to obtain a three-dimensional interconnected graphene-diamond reinforced copper-based composite material, wherein the applied pressure adopted by the six-sided top press to apply and maintain the pressure on the preform is 2-4 GPa, and the holding time is 0.5-24 h; Step 4: heat-treating the three-dimensional interconnected graphene-diamond reinforced copper-based composite material to complete the preparation.

2. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 1, the pore size of the porous copper is 10 μm-10 mm, and the porosity is 40-90%.

3. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 1, the parameters of the chemical vapor deposition are: the carbon-containing gas accounts for 5-70% of the mass flow rate of the total gas in the furnace.

4. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 1, the growth temperature of the growth process is 800-1200 ° C, and the growth pressure is 10 3 -10 5 Pa, plasma current density is 10-40 mA / cm 2 .

5. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 2, the particle size of the diamond particles is 50-900 μm, and the size of the diamond particles is always smaller than the aperture of the porous copper holes in which the graphene is grown.

6. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 2, the carbide is WC, MoC, Cr7C3, TiC, B4C, SiC, ZrC, NbC and VC.

7. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step three, the sintering temperature of the hot pressing sintering is 800-1100° C., the sintering pressure when using a six-sided top press is 4-8 GPa, and the holding time after hot pressing sintering is 10-30 min.

8. The method for preparing a three-dimensional interconnected graphene-diamond reinforced copper-based composite material according to claim 1, characterized in that: In the step 4, the heat treatment temperature is 200-400°C and the time is 10-120 min.

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