A copper graphene composite material and a preparation method and preparation equipment thereof

Abstract

This invention belongs to the field of copper-based composite materials, and particularly relates to a copper-graphene composite material, its preparation method, and preparation equipment. The copper-graphene composite material preparation equipment provided by this invention includes: a furnace body; a lifting device disposed within the furnace body, the lifting device being equipped with a fixing fixture for vertically fixing a copper rod; a heat-resistant sleeve for placing the copper rod, the lower opening of the heat-resistant sleeve being provided with a fastening clamp; an electromagnetic induction coil disposed within the furnace body, the electromagnetic induction coil being able to electromagnetically induction heat the copper rod in the heat-resistant sleeve above the fastening clamp during the up-and-down movement of the lifting device; and a cooling pool disposed within the furnace body and located below the electromagnetic induction coil, the cooling pool being able to cool the copper rod passing downward through the induction coil during the up-and-down movement of the lifting device. The equipment provided by this invention can be used to prepare macroscopic copper-graphene composite materials, and the preparation process is short, efficient, and economical.

Description

Technical Field

[0001] This invention belongs to the field of copper-based composite materials, and particularly relates to a copper-graphene composite material and its preparation method and equipment. Background Technology

[0002] The rational distribution of graphene in copper and copper alloy matrices can effectively improve their mechanical and electrical properties. In recent years, the manufacturing technology of copper-based graphene composite materials has become a research hotspot in the field of high-strength and high-conductivity materials.

[0003] Currently, copper-graphene composites are mostly achieved through surface catalytic growth (such as chemical vapor deposition) and copper-graphene mixing (such as powder metallurgy). The raw materials used are often expensive substances like copper foil, copper powder, and graphene, and the preparation processes require precise and controllable parameters and are time-consuming. Furthermore, to manufacture macroscopic materials using current methods, it is often necessary to add material accumulation, hot deformation (hot pressing, hot rolling), or hot plastic deformation processes such as stirring and swirl extrusion. These long-process, long-cycle processes significantly increase the manufacturing cost of the target product. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a copper-graphene composite material and its preparation method and equipment. The equipment provided by this invention can be used to prepare macroscopic copper-graphene composite materials, and the preparation process is short, efficient and economical.

[0005] This invention provides an apparatus for preparing copper-graphene composite materials, comprising:

[0006] The furnace body is equipped with a furnace cover and an air inlet.

[0007] The lifting device installed inside the furnace body is equipped with a fixing fixture for vertically fixing the copper rod.

[0008] A heat-resistant sleeve for placing copper rods, wherein a fastening clamp is provided at the lower opening of the heat-resistant sleeve;

[0009] An electromagnetic induction coil is installed inside the furnace body. The electromagnetic induction coil does not move up and down with the lifting device, but can electromagnetically heat the copper rod in the heat-resistant sleeve above the fastening clamp during the up and down movement of the lifting device.

[0010] A cooling pool is installed inside the furnace and located below the electromagnetic induction coil. The cooling pool does not move up and down with the lifting device, but can cool the copper rod passing downward through the induction coil during the up and down movement of the lifting device.

[0011] Preferably, the lifting device includes a lifting rod and a clamping fixture for vertically fixing the copper rod.

[0012] This invention provides a method for preparing copper-graphene composite materials. The method involves preparing copper-graphene composite materials in the equipment described in the above technical solution, and includes the following processes:

[0013] a) Place the copper rod in the heat-resistant sleeve of the equipment, with both the upper and lower ends of the copper rod protruding from the heat-resistant sleeve; then use the fastening clamp set at the lower opening of the heat-resistant sleeve to seal and fasten the lower opening of the heat-resistant sleeve.

[0014] b) Open the furnace body and furnace cover of the equipment, pass the copper rod fixed in the heat-resistant sleeve through the electromagnetic induction coil set in the furnace body, and fix it on the lifting device in the furnace body; adjust the height of the copper rod so that the electromagnetic induction coil is close to the lower end of the heat-resistant sleeve and above the fastening clamp.

[0015] c) Close the furnace body and furnace cover of the equipment, evacuate the furnace body, and then introduce H2 and CH4 into the inner cavity of the furnace body through the air inlet of the furnace body;

[0016] d) Turn on the electromagnetic induction coil to perform electromagnetic induction heating on the heat-resistant sleeve and copper rod located in the coil height and adjacent areas above and below;

[0017] e) After the copper rod located in the heating area of ​​the electromagnetic induction coil melts, the lifting device is activated, so that the combination of the copper rod and the heat-resistant sleeve moves downward relative to the electromagnetic induction coil and is immersed in the cooling pool located below the electromagnetic induction coil during the downward movement. The molten material in the heat-resistant sleeve solidifies and cools in the cooling pool to obtain the copper-graphene composite material.

[0018] Preferably, in step a), the copper rod is made of pure copper or a copper alloy; the volume ratio of the heat-resistant sleeve to the copper rod is (0.5-5):1.

[0019] Preferably, in step c), the vacuum level inside the furnace cavity after evacuation is 10. -1 ~10 -4 Pa; the partial pressure of H2 in the furnace cavity is 0.1 to 10 atm; the partial pressure of CH4 in the furnace cavity is 0.1 to 10 atm.

[0020] Preferably, in step d), the frequency of the electromagnetic induction heating is 1 to 100 kHz; the power of the electromagnetic induction heating is 1 to 50 kW; and the temperature of the electromagnetic induction heating is 1083 to 2000 °C.

[0021] Preferably, in step e), the downward movement speed is 0.5 to 100 mm / min.

[0022] Preferably, in step e), the cooling medium in the cooling pool is water, cooling oil, or liquid metal.

[0023] Preferably, the preparation method further includes: heat-treating the copper-graphene composite material obtained in step e).

[0024] This invention provides a copper-graphene composite material, which is prepared according to the preparation method described in the above technical solution.

[0025] Compared with existing technologies, this invention provides a copper-graphene composite material, its preparation method, and preparation equipment. The copper-graphene composite material preparation equipment provided by this invention includes: a furnace body, the furnace body being provided with a furnace cover and an air inlet; a lifting device disposed within the furnace body, the lifting device being provided with a fixing fixture for vertically fixing a copper rod; a heat-resistant sleeve for placing the copper rod, the heat-resistant sleeve having a fastening clamp at its lower opening; an electromagnetic induction coil disposed within the furnace body, the electromagnetic induction coil not moving up and down with the lifting device, and capable of electromagnetically inducing heat on the copper rod in the heat-resistant sleeve above the fastening clamp during the up and down movement of the lifting device; and a cooling pool disposed within the furnace body and located below the electromagnetic induction coil, the cooling pool not moving up and down with the lifting device, and capable of cooling the copper rod passing downward through the induction coil during the up and down movement of the lifting device. The specific process for preparing copper-graphene composite materials using this equipment includes: a) placing a copper rod in the heat-resistant sleeve of the equipment, with both ends of the copper rod protruding from the heat-resistant sleeve; then sealing and securing the lower end of the heat-resistant sleeve using a fastening clamp located at the lower opening of the heat-resistant sleeve; b) opening the furnace cover of the equipment, passing the copper rod fixed in the heat-resistant sleeve through an electromagnetic induction coil located inside the furnace, and fixing it to a lifting device inside the furnace; adjusting the height of the copper rod so that the electromagnetic induction coil is close to the lower end of the heat-resistant sleeve and above the fastening clamp; c) shutting down the equipment. The furnace body and lid are evacuated, and then H2 and CH4 are introduced into the furnace cavity through the furnace body's air inlet; d) The electromagnetic induction coil is turned on to electromagnetically induction heat the heat-resistant sleeve and copper rod located in the coil's height and adjacent areas above and below; e) After the copper rod located in the heating area of ​​the electromagnetic induction coil melts, the lifting device is turned on, causing the combination of copper rod and heat-resistant sleeve to move downward relative to the electromagnetic induction coil, and during the downward movement, it is immersed in the cooling pool located below the electromagnetic induction coil. The molten material in the heat-resistant sleeve solidifies and cools in the cooling pool to obtain a copper-graphene composite material. The equipment provided by this invention can prepare macroscopic copper-graphene composite materials using copper rods, H2, and CH4 as raw materials, and has the advantages of short preparation process, high efficiency, and good economy.

[0026] To more clearly illustrate the technical principle of preparing copper-graphene composite materials according to this invention, the core technical aspects of this invention are explained below:

[0027] (1) Establishment of preparation conditions: Under the environmental pressure formed by hydrogen (H2) and methane (CH4), copper rods wrapped in heat-resistant sleeves were subjected to a sequential "melting-solidification" process with electromagnetic induction as the heating source.

[0028] (2) Material (carbon and hydrogen source) basis: The methane gas on the surface of the copper rod melting section is decomposed into carbon atoms or carbon atom clusters due to the high temperature of the copper melt. Under the dual action of the Marangoni effect and electromagnetic heating to form melt convection, the carbon atoms or atom clusters enter the interior of the copper melt and become the carbon source required for graphene nucleation and growth. At the same time, hydrogen gas is decomposed into hydrogen atoms in the melting section and dissolved into the copper melt, becoming the hydrogen source required for pore growth.

[0029] (3) Generation of physical field (temperature and temperature gradient): The bottom of the copper rod is exposed to the heat-resistant sleeve and gradually immersed in the cooling pool during the sequential melting process to achieve enhanced cooling and obtain a high temperature gradient that gradually decreases from top to bottom; in addition, the heat-resistant sleeve cools slowly during the cooling process due to its large heat capacity and low thermal conductivity, thus forming a temperature gradient that gradually decreases from the outer surface of the copper rod (due to the heat insulation of the slowly cooling heat-resistant material sleeve) to the core of the copper rod.

[0030] (4) The nucleation and growth process of graphene: During the melting process of the copper rod, the copper rod moves downward and gradually solidifies and cools after passing through the electromagnetic induction coil. H2 is a small molecule gas that can reach the surface of the copper melting zone through the gap formed between the surface of the copper rod and the inner wall of the sleeve. H atoms dissolved in the copper melt aggregate into H2 molecules. H2 molecules gather into tiny pores and grow into large pores. Due to the presence of the vertical temperature field during the "melting-solidification" process, the pores grow in a long, straight and uniform manner and finally solidify in the solidified copper rod. During the same process, C atoms or C atom clusters segregate from the copper temperature field from top to bottom and from the surface to the inside of the copper rod and begin to aggregate and assemble on the surface of the pore wall. Under the influence of the H2 atmosphere, graphene crystal domains grow. Finally, after the copper rod is completely solidified and cooled, the copper rod has a structure with regular porous structure and the pore walls are covered with graphene.

[0031] (5) Continuous coverage improvement: Furthermore, it is preferable to heat treat the material at the end; after heat treatment, the C atoms remaining in the copper grains of the copper rod can segregate to the pore wall in a larger amount, thereby improving the coverage of graphene on the pore wall.

[0032] To better illustrate the advantages of the technical solution of the present invention, the technical effects that the technical solution of the present invention can achieve are listed and described below:

[0033] (1) Using copper rods as raw materials instead of deep-processed copper products (copper foil, copper powder, etc.) significantly reduces the price of raw materials;

[0034] (2) The preparation process does not require the addition of graphene as a raw material through physical methods. Compared with the method of mixing copper and graphene, this method avoids the graphene dispersion and powder mixing processes commonly used in the forming process, thus reducing the process cost.

[0035] (3) It can directly realize the preparation of macroscopic three-dimensional copper graphene composite materials, which is significantly different from the chemical vapor deposition method for catalytic growth of graphene on copper surface. It is only suitable for growing graphene on copper sheets and foils, and subsequent lay-up and hot pressing processes are required to achieve macroscopic quantification of composite materials. In comparison, the process of this invention is shorter and the process cost is lower.

[0036] (4) In the composite material prepared by the present invention, graphene grows and is regularly distributed inside the copper bulk material. Compared with the method of mixing copper and graphene and catalytically growing graphene on the copper surface, the present invention has intrinsic material anti-oxidation and anti-corrosion advantages in terms of raw material storage, process procedures, and target product storage and transportation, which is conducive to maintaining material performance. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0038] Figure 1 This is a schematic diagram of the structure of the copper-graphene composite material preparation equipment provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the combination of the copper rod and the heat-resistant sleeve provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the technical mechanism provided in the embodiments of the present invention;

[0041] Figure 4 These are morphological characterization diagrams of the copper-graphene composite material provided in the embodiments of the present invention;

[0042] Figure 5 This is a diagram showing the test point locations for the hole wall morphology and energy dispersive spectroscopy analysis under a scanning electron microscope field of view, provided in an embodiment of the present invention.

[0043] Figure 6 This is the energy spectrum analysis result of test point Spot1 provided in this embodiment of the invention;

[0044] Figure 7 This is the energy spectrum analysis result of test point Spot2 provided in this embodiment of the invention;

[0045] Figure 8 This is the energy dispersive spectroscopy (EDS) result spectrum of test point Spot3 provided in this embodiment of the invention;

[0046] Figure 9 This is the energy spectrum analysis result of test point Spot4 provided in this embodiment of the invention;

[0047] Figure 10 This is the energy spectrum analysis result of test point Spot5 provided in this embodiment of the invention;

[0048] Figure 11 This is the energy spectrum analysis result of test point Spot6 provided in this embodiment of the invention;

[0049] Figure 12 This is a Raman spectral analysis result spectrum provided in an embodiment of the present invention.

[0050] Appendix Figure 1 The markings are as follows: 1 is the furnace body, 2 is the clamping fixture, 3 is the heat-resistant sleeve, 4 is the electromagnetic induction coil, 5 is the fastening clamp, 6 is the copper rod, 7 is the cooling pool, and 8 is the lifting rod. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] The present invention provides an apparatus for preparing copper graphene composite materials, comprising: a furnace body 1, a lifting device, a heat-resistant sleeve 3, an electromagnetic induction coil 4, and a cooling pool 7.

[0053] In the preparation equipment provided by the present invention, the furnace body 1 is provided with a furnace cover and an air inlet.

[0054] In the preparation equipment provided by the present invention, the lifting device is disposed inside the furnace body 1, and the lifting device is provided with a fixing fixture for vertically fixing the copper rod. In the present invention, the lifting device preferably includes a clamping fixture 2 for vertically fixing the copper rod and a lifting rod 8, and the clamping fixture 2 and the lifting rod 8 are preferably fixed together by bolts.

[0055] In the preparation apparatus provided by the present invention, the heat-resistant sleeve 3 is used to place and wrap the copper rod, and a fastening clamp 5 is provided at its lower opening. In the present invention, the radial cross-section of the heat-resistant sleeve 3 can be circular, square or other geometric shapes; the heat-resistant sleeve 3 has low thermal conductivity and thermal conductivity coefficient, and its material includes but is not limited to graphite, silicon carbide, silicon nitride or other high-temperature resistant materials, preferably graphite.

[0056] In the preparation equipment provided by this invention, the electromagnetic induction coil 4 is disposed inside the furnace body 1. The electromagnetic induction coil 4 does not move up and down with the lifting device, and can electromagnetically induction heat the copper rod in the heat-resistant sleeve 3 above the fastening clamp 5 during the up and down movement of the lifting device. In this invention, the electromagnetic induction coil 4 is preferably a single-strand coil, but a multi-turn coil can also be used.

[0057] In the preparation equipment provided by the present invention, the cooling pool 7 is arranged inside the furnace body 1 and located below the electromagnetic induction coil 4; the cooling pool 7 does not move up and down with the lifting device, and can cool the copper rod passing down through the induction coil 4 during the up and down movement of the lifting device.

[0058] This invention also provides a method for preparing a copper-graphene composite material, wherein the copper-graphene composite material is prepared in the equipment described in the above technical solution, and includes the following processes:

[0059] a) Place the copper rod 6 into the heat-resistant sleeve 3, with both the upper and lower ends of the copper rod 6 protruding from the heat-resistant sleeve 3; then use the fastening clamp 5 located at the lower opening of the heat-resistant sleeve 3 to seal and fasten the lower opening of the heat-resistant sleeve 3.

[0060] b) Open the furnace cover of the furnace body 1, pass the copper rod 6 fixed in the heat-resistant sleeve 3 through the electromagnetic induction coil 4, and fix it on the lifting device inside the furnace body; adjust the height of the copper rod 6 so that the electromagnetic induction coil 4 is close to the lower end of the heat-resistant sleeve 3 and above the fastening clamp 5.

[0061] c) Close the furnace cover of furnace body 1, evacuate furnace body 1, and then introduce H2 and CH4 into the inner cavity of the furnace body through the air inlet of furnace body 1.

[0062] d) Turn on the electromagnetic induction coil 4 to perform electromagnetic induction heating on the heat-resistant sleeve 3 and copper rod 6 located in the coil height and adjacent areas above and below;

[0063] e) After the copper rod 6 located in the heating area of ​​the electromagnetic induction coil 4 melts, the lifting device is activated, so that the combination of the copper rod 6 and the heat-resistant sleeve 3 moves downward relative to the electromagnetic induction coil 4 and is immersed in the cooling pool 7 during the downward movement. The molten material in the heat-resistant sleeve 3 is cooled and solidified in the cooling pool 7 to obtain the copper graphene composite material.

[0064] In the preparation method provided by this invention, in step a), the copper rod 6 is composed of pure copper or a copper alloy; the purity of the pure copper is preferably 2-5N (99%-99.999%); the copper alloy includes, but is not limited to, copper-manganese alloy, copper-zinc alloy, copper-tin alloy, copper-nickel alloy, etc.; the radial cross-section of the copper rod 6 can be circular, square, or other geometric shapes. In this invention, the copper rod 6 can be processed into a structure that is thinner at the top and thicker at the bottom, or a structure with equal thickness at both the top and bottom, or it can be assembled by stacking thin copper rods and thick copper rods. The specific combination method of the copper rod 6 and the heat-resistant sleeve 3 can be as follows: Figure 2 As shown, Figure 2 In the diagram, figure a shows a copper rod of equal thickness at both ends, figure b shows a copper rod that is thinner at the top and thicker at the bottom, and figure c shows a thin copper rod and a thick copper rod stacked on top of each other. In this invention, the volume ratio of the heat-resistant sleeve 3 to the copper rod 6 is preferably (0.5-5):1, more preferably (0.8-2):1, and specifically can be 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2:1.

[0065] In the preparation method provided by the present invention, in step c), the vacuum degree of the furnace cavity after evacuation is preferably 10. -1 ~10 -4 Pa, specifically 10 -1 Pa, 10 -2 Pa, 10 -3 Pa or 10 -4 Pa; the partial pressure of H2 in the furnace cavity is preferably 0.1-10 atm, specifically 0.1 atm, 0.5 atm, 1 atm, 1.5 atm, 2 atm, 2.5 atm, 3 atm, 3.5 atm, 4 atm, 4.5 atm, 5 atm, 6 atm, 7 atm, 8 atm, 9 atm, or 10 atm; the partial pressure of CH4 in the furnace cavity is 0.1-10 atm, specifically 0.1 atm, 0.5 atm, 1 atm, 1.5 atm, 2 atm, 2.5 atm, 3 atm, 3.5 atm, 4 atm, 4.5 atm, 5 atm, 6 atm, 7 atm, 8 atm, 9 atm, or 10 atm. In this invention, Ar or N2 can be introduced if necessary to increase the total gas pressure in the furnace cavity. The inlet valve is closed after the internal pressure of the furnace body 1 reaches the preset value.

[0066] In the preparation method provided by this invention, in step d), the frequency of the electromagnetic induction heating is preferably 1-100 kHz, specifically 1 kHz, 5 kHz, 10 kHz, 20 kHz, 30 kHz, 40 kHz, 50 kHz, 60 kHz, 70 kHz, 80 kHz, 90 kHz, or 100 kHz; the power of the electromagnetic induction heating is preferably 1-50 kW, specifically 1 kW, 5 kW, 10 kW, or 15 kW. The heating temperature is 20KW, 25KW, 30KW, 35KW, 40KW, 45KW, or 50KW; the electromagnetic induction heating temperature is above the melting point of the copper rod, preferably 1083-2000℃, specifically 1100℃, 1150℃, 1200℃, 1250℃, 1300℃, 1350℃, 1400℃, 1450℃, 1500℃, 1600℃, 1700℃, 1800℃, 1900℃, or 2000℃.

[0067] In the preparation method provided by the present invention, in step e), the downward moving speed is preferably 0.5 to 100 mm / min, specifically 0.5 mm / min, 1 mm / min, 5 mm / min, 10 mm / min, 15 mm / min, 20 mm / min, 25 mm / min, 30 mm / min, 40 mm / min, 50 mm / min, 60 mm / min, 70 mm / min, 80 mm / min, 90 mm / min or 100 mm / min; the cooling medium in the cooling pool includes, but is not limited to, water, cooling oil or liquid metal, preferably liquid gallium metal, gallium-indium alloy or gallium-indium-tin alloy.

[0068] In the preparation method provided by the present invention, in order to reduce the solid solubility of C in copper grains and increase the content and coverage of graphene on the pore walls of the material, it is preferable to perform heat treatment on the copper-graphene composite material obtained in step e); the heat treatment can be carried out in a muffle furnace or in the equipment provided by the present invention. In this invention, the heat treatment temperature in the muffle furnace is preferably 250–1050°C, more preferably 300–950°C, specifically 300°C, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, or 950°C; the heat treatment time in the muffle furnace is preferably 20–60 min, specifically 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, or 60 min; after the heat treatment is completed in the muffle furnace, cooling is performed, preferably by natural cooling or air cooling. In this invention, the specific process of heat treatment in the equipment provided by this invention is that the copper graphene composite material is subjected to repeated (or multiple) sequential "heating-cooling" in the furnace body 1. The temperature at which the copper graphene composite material is heated is preferably 300-950℃, specifically 300℃, 350℃, 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, 900℃, or 950℃; the number of heat treatments is preferably ≥1.

[0069] The present invention also provides a copper-graphene composite material, which is prepared according to the preparation method described in the above technical solution.

[0070] To more clearly illustrate the technical principle of preparing copper-graphene composite materials according to this invention, the core technical aspects of this invention are explained below:

[0071] (1) Establishment of preparation conditions: Under the environmental pressure formed by hydrogen (H2) and methane (CH4), copper rods wrapped in heat-resistant sleeves were subjected to a sequential "melting-solidification" process with electromagnetic induction as the heating source.

[0072] (2) Material (carbon and hydrogen source) basis: The methane gas on the surface of the copper rod melting section is decomposed into carbon atoms or carbon atom clusters due to the high temperature of the copper melt. Under the dual action of the Marangoni effect and electromagnetic heating to form melt convection, the carbon atoms or atom clusters enter the interior of the copper melt and become the carbon source required for graphene nucleation and growth. At the same time, hydrogen gas is decomposed into hydrogen atoms in the melting section and dissolved into the copper melt, becoming the hydrogen source required for pore growth.

[0073] (3) Generation of physical field (temperature and temperature gradient): The bottom of the copper rod is exposed to the heat-resistant sleeve and gradually immersed in the cooling pool during the sequential melting process to achieve enhanced cooling and obtain a high temperature gradient from top to bottom (gradually decreasing); in addition, the heat-resistant sleeve cools slowly during the cooling process due to its large heat capacity and low thermal conductivity, thus forming a temperature gradient that gradually decreases from the outer surface of the copper rod (due to the heat insulation of the slowly cooling heat-resistant material sleeve) to the core of the copper rod.

[0074] (4) The nucleation and growth process of graphene: During the melting process of the copper rod, the copper rod moves downward and gradually solidifies and cools after passing through the electromagnetic induction coil. H2 is a small molecule gas that can reach the surface of the copper melting zone through the gap formed between the surface of the copper rod and the inner wall of the sleeve. H atoms dissolved in the copper melt aggregate into H2 molecules. H2 molecules gather into tiny pores and grow into large pores. Due to the presence of the vertical temperature field during the "melting-solidification" process, the pores grow in a long, straight and uniform manner and finally solidify in the solidified copper rod. During the same process, C atoms or C atom clusters segregate from the copper temperature field from top to bottom and from the surface to the inside of the copper rod and begin to aggregate and assemble on the surface of the pore wall. Under the influence of the H2 atmosphere, graphene domains are grown. Finally, after the copper rod is completely solidified and cooled, the copper rod has a regular porous structure with the pore walls covered with graphene.

[0075] (5) Continuous coverage improvement: Furthermore, it is preferable to heat treat the material at the end; after heat treatment, the C atoms dissolved in the copper grains of the copper rod can segregate to the pore wall in a larger amount, thereby improving the coverage of graphene on the pore wall.

[0076] To better illustrate the advantages of the technical solution of the present invention, the technical effects that the technical solution of the present invention can achieve are listed and described below:

[0077] (1) Using copper rods as raw materials instead of deep-processed copper products (copper foil, copper powder, etc.) significantly reduces the price of raw materials;

[0078] (2) The preparation process does not require the addition of graphene as a raw material through physical methods. Compared with the method of mixing copper and graphene, this method avoids the graphene dispersion and powder mixing processes commonly used in the forming process, thus reducing the process cost.

[0079] (3) It can directly realize the preparation of macroscopic three-dimensional copper graphene composite materials, which is significantly different from the chemical vapor deposition method for catalytic growth of graphene on copper surface. It is only suitable for growing graphene on copper sheets and foils, and subsequent lay-up and hot pressing processes are required to achieve macroscopic quantification of composite materials. In comparison, the process of this invention is shorter and the process cost is lower.

[0080] (4) In the composite material prepared by the present invention, graphene grows and is regularly distributed inside the copper bulk material. Compared with the method of mixing copper and graphene and catalytically growing graphene on the copper surface, the present invention has intrinsic material anti-oxidation and anti-corrosion advantages in terms of raw material storage, process procedures, and target product storage and transportation, which is conducive to maintaining material performance.

[0081] For clarity, the following examples will be used to provide a detailed description.

[0082] Example 1

[0083] exist Figure 1 The equipment shown is used to prepare copper-graphene composite materials. The specific process includes:

[0084] (1) Place the copper rod 6 in the heat-resistant sleeve 3, with both the upper and lower ends of the copper rod 6 protruding from the sleeve. Use the fastening clamp 5 to seal and fasten the lower end of the heat-resistant sleeve 3, so that the combination of the copper rod 6 and the heat-resistant sleeve 3 will not move relative to each other during the subsequent "melting-solidification" process. Among them, the copper rod 6 is a 3N purity copper rod with a diameter of 12mm (equal thickness at both ends), and the heat-resistant sleeve 3 is made of hot-pressed graphite. The volume ratio of the heat-resistant sleeve 3 to the copper rod 6 is 1.2:1.

[0085] (2) Open the furnace cover of furnace body 1, pass the combination of copper rod 6 and heat-resistant sleeve 3 through electromagnetic induction coil 4, and clamp and fix it in clamping fixture 2; the lower end of clamping fixture 2 is connected to lifting rod 8 and fixed with bolts; adjust the height of copper rod 6 so that electromagnetic induction coil 4 is close to the lower end of heat-resistant sleeve 3 and above fastening clamp 5. Among them, in order to reduce the melting zone of copper rod 6, electromagnetic induction coil 4 adopts single-strand coil; clamping fixture 2 fixes the upper and lower ends of copper rod 6 to ensure that the length of copper rod does not change during the subsequent "melting-solidification" process.

[0086] (3) Close the furnace cover of furnace body 1, evacuate the furnace chamber, and then open the H2 and CH4 intake valves to fill the inner cavity of furnace body 1 with the mixed gas. After the pressure inside the furnace chamber reaches the preset value, close the intake valves. The partial pressure of H2 is 1.5 atm and the partial pressure of CH4 is 0.5 atm.

[0087] (4) The electromagnetic induction coil 4 is turned on, and the heat-resistant sleeve 3 and copper rod 6 located in the coil height and adjacent areas above and below are heated. The electromagnetic induction heating has a frequency of 40KHz, a power of 20KW, and the temperature of the copper rod melting zone is 1250℃.

[0088] (5) After the copper rod 6 located in the heating area of ​​the electromagnetic induction coil 4 melts, the lifting rod 8 is activated, causing the combination of the copper rod 6 and the heat-resistant sleeve 3 to move downward relative to the electromagnetic induction coil 4, and to be immersed in the cooling pool 7 during the downward movement, until all the copper rod 6 in the heat-resistant sleeve 3 has been sequentially "melted-solidified". The downward movement speed is set to 15 mm / min, and the cooling medium in the cooling pool 7 is liquid gallium metal.

[0089] (6) After removing the mixed gas from the inner cavity of the furnace body 1, the porous copper graphene composite material is taken out.

[0090] In this embodiment, the core technical principle for preparing porous copper-graphene composite materials is as follows: Figure 3 As shown, specifically: ① Under the combined effects of electromagnetic heating and the Marangoni effect, carbon (C) decomposed at high temperature enters the copper molten zone; ② The temperature gradient from top to bottom and from the surface to the interior further promotes the diffusion of C atoms and atomic clusters into the copper interior. Given that Cu has extremely low C solid solubility, this invention, through the above measures, allows a large amount of C to segregate into the Cu matrix.

[0091] The morphology of the porous copper-graphene composite material prepared in this embodiment was characterized, and the results are as follows: Figure 4 As shown, Figure a) is a photograph of the radial and axial cross-sections of the porous copper-graphene composite material, and Figure b) is a micrograph of the radial cross-section of the porous copper-graphene composite material. Figure a) shows that the copper-graphene composite material prepared in this embodiment has a regularly oriented porous structure, with a calculated pore volume ratio > 42%. Figure b) shows that graphene sheet structures are distributed on the pore walls.

[0092] The elemental composition of the porous copper-graphene composite material prepared in this embodiment was tested and characterized by Raman spectroscopy. The results are as follows: Figures 5-12 As shown; where, Figure 5 The locations of test points for hole wall morphology and energy dispersive spectroscopy analysis under the field of view of scanning electron microscopy; Figures 6-11 for Figure 5 The energy dispersive spectroscopy (EDS) analysis results for each test point and the corresponding elemental content data are detailed in Tables 1-6. Figure 12 The results are the Raman spectra of the field of view.

[0093] Table 1. Elemental content data for Spot 1

[0094] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 6.75 25.58 92.66 12.70 0.0165 1.3118 0.1869 1.0000 OK 3.58 10.20 206.24 9.50 0.0157 1.2623 0.3476 1.0000 CuK 89.67 64.23 2769.17 2.08 0.8625 0.9591 1.0019 1.0009

[0095] Table 2 Elemental content data for Spot 2

[0096] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 4.08 17.32 53.37 14.21 0.0098 1.3302 0.1810 1.0000 OK 2.42 7.71 141.67 10.30 0.0111 1.2800 0.3598 1.0000 CuK 93.50 74.97 2839.78 2.05 0.9123 0.9740 1.0012 1.0006

[0097] Table 3. Elemental content data for Spot 3

[0098] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 3.92 16.71 50.08 15.06 0.0094 1.3308 0.1808 1.0000 OK 2.47 7.91 141.93 10.30 0.0114 1.2806 0.3609 1.0000 CuK 93.61 75.38 2780.33 2.08 0.9139 0.9745 1.0013 1.0006

[0099] Table 4. Elemental content data for Spot 4

[0100] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 5.26 21.35 69.52 13.12 0.0128 1.3233 0.1832 1.0000 OK 2.62 7.98 150.59 10.30 0.0118 1.2734 0.3537 1.0000 CuK 92.12 70.67 2794.75 2.07 0.8941 0.9684 1.0015 1.0007

[0101] Table 5. Elemental content data for Spot 5

[0102] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 3.68 15.76 47.30 15.17 0.0088 1.3316 0.1805 1.0000 OK 2.58 8.30 150.23 10.21 0.0120 1.2814 0.3626 1.0000 CuK 93.74 75.94 2810.33 2.06 0.9157 0.9751 1.0012 1.0005

[0103] Table 6. Elemental content data for Spot 6

[0104] Element Weight% Atomic% NetInt. Error% Kratio Z A F CK 3.86 16.52 49.23 15.09 0.0093 1.3317 0.1805 1.0000 OK 2.34 7.51 134.40 10.34 0.0108 1.2815 0.3609 1.0000 CuK 93.81 75.97 2790.92 2.06 0.9164 0.9752 1.0012 1.0005

[0105] pass Figures 5-12 It can be seen that the C element is aggregated on the surface of the pore wall in a planar distribution. Further Raman spectroscopy characterization shows that it has obvious D peak, G peak and 2D peak characteristics. The 2D peak has a smaller peak width and a higher peak height than the G peak, indicating that it is mainly few-layer graphene.

[0106] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a copper-graphene composite material, characterized in that, Prepare copper-graphene composite materials in an apparatus used for preparing copper-graphene composite materials; The equipment for preparing copper-graphene composite materials includes: The furnace body is equipped with a furnace cover and an air inlet. The lifting device installed inside the furnace body is equipped with a fixing fixture for vertically fixing the copper rod. A heat-resistant sleeve for placing copper rods, wherein a fastening clamp is provided at the lower opening of the heat-resistant sleeve; An electromagnetic induction coil is installed inside the furnace body. The electromagnetic induction coil does not move up and down with the lifting device, but can electromagnetically heat the copper rod in the heat-resistant sleeve above the fastening clamp during the up and down movement of the lifting device. A cooling pool is installed inside the furnace and located below the electromagnetic induction coil. The cooling pool does not move up and down with the lifting device, but can cool the copper rod passing down through the induction coil during the up and down movement of the lifting device. The preparation process includes: a) Place the copper rod in the heat-resistant sleeve of the equipment, with both the upper and lower ends of the copper rod protruding from the heat-resistant sleeve; then use the fastening clamp set at the lower opening of the heat-resistant sleeve to seal and fasten the lower opening of the heat-resistant sleeve. b) Open the furnace body and furnace cover of the equipment, pass the copper rod fixed in the heat-resistant sleeve through the electromagnetic induction coil set in the furnace body, and fix it on the lifting device in the furnace body; adjust the height of the copper rod so that the electromagnetic induction coil is close to the lower end of the heat-resistant sleeve and is located above the fastening clamp. c) Close the furnace body and furnace cover of the equipment, evacuate the furnace body, and then introduce H2 and CH4 into the inner cavity of the furnace body through the air inlet of the furnace body; d) Turn on the electromagnetic induction coil to perform electromagnetic induction heating on the heat-resistant sleeve and copper rod located in the coil height and adjacent areas above and below; e) After the copper rod located in the heating area of ​​the electromagnetic induction coil melts, the lifting device is activated, so that the combination of the copper rod and the heat-resistant sleeve moves downward relative to the electromagnetic induction coil and is immersed in the cooling pool located below the electromagnetic induction coil during the downward movement. The molten material in the heat-resistant sleeve solidifies and cools in the cooling pool to obtain the copper-graphene composite material.

2. The preparation method according to claim 1, characterized in that, The lifting device includes a lifting rod and a clamping fixture for vertically fixing the copper rod.

3. The preparation method according to claim 1, characterized in that, In step a), the copper rod is made of pure copper or a copper alloy; the volume ratio of the heat-resistant sleeve to the copper rod is (0.5~5):

1.

4. The preparation method according to claim 1, characterized in that, In step c), the vacuum level inside the furnace cavity after evacuation is 10. -1 ~10 -4 Pa; the partial pressure of H2 in the furnace cavity is 0.1~10 atm; the partial pressure of CH4 in the furnace cavity is 0.1~10 atm.

5. The preparation method according to claim 1, characterized in that, In step d), the frequency of the electromagnetic induction heating is 1~100kHz; the power of the electromagnetic induction heating is 1~50kW; and the temperature of the electromagnetic induction heating is 1083~2000℃.

6. The preparation method according to claim 1, characterized in that, In step e), the downward movement speed is 0.5~100mm / min.

7. The preparation method according to claim 1, characterized in that, In step e), the cooling medium in the cooling pool is water, cooling oil, or liquid metal.

8. The preparation method according to claim 1, characterized in that, Also includes: The copper-graphene composite material obtained in step e) is subjected to heat treatment.

9. A copper-graphene composite material, characterized in that, It is prepared according to the preparation method according to any one of claims 1 to 8.

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