Preparation method of graphene copper-based composite material
By combining free diffusion of graphene dispersion with lamination, annealing, and rolling processes, the problems of uneven distribution and weak interfacial bonding in graphene-copper composite materials were solved, improving the overall performance of the material and making it suitable for industrial production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- KUNMING UNIV OF SCI & TECH
- Filing Date
- 2026-02-02
- Publication Date
- 2026-05-05
AI Technical Summary
Existing methods for preparing graphene-reinforced copper-based composites suffer from problems such as uneven graphene distribution, weak interfacial bonding, complex processes, high costs, and insufficient performance.
By employing a combination of free diffusion of graphene dispersion and stacking cold pressing, hot pressing, annealing, and rolling processes, the uniform distribution of graphene in the copper matrix and the interfacial bonding strength are improved, simplifying the preparation process.
It improves the mechanical, electrical, and thermal properties of graphene-copper composite materials, reduces process complexity and cost, and is suitable for industrial applications.
Smart Images
Figure CN121973535A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of copper-based composite materials technology, and specifically relates to a method for preparing graphene copper-based composite materials. Background Technology
[0002] Copper is widely used in electronics, power, machinery, and energy fields due to its excellent electrical and thermal conductivity, as well as its good mechanical properties. However, pure copper has poor mechanical properties, making it difficult to meet the increasingly stringent requirements of industrial technology. Therefore, copper-based composite materials are usually obtained by introducing reinforcing phases into the copper matrix to improve the mechanical properties of copper-based composite materials and further enhance their electrical and thermal conductivity.
[0003] Graphene, due to its excellent mechanical properties, electrical conductivity, and thermal conductivity, has become an ideal reinforcement for copper-based composites. Currently, the main preparation methods for graphene-reinforced copper-based composites include ball milling, molecular-level mixing, electrochemical deposition, chemical vapor deposition, and powder metallurgy. Among these, ball milling easily introduces impurities and requires a long milling time to achieve a good composite of copper and graphene; the prolonged milling time can also damage the graphene structure, affecting its electrical and thermal conductivity. Molecular-level mixing mainly prepares composites through oxidation and reduction processes; however, oxidation and reduction processes easily introduce defects, and the preparation process is relatively cumbersome, limiting its large-scale application. Electrochemical deposition mainly uses an electric current to co-deposit graphene oxide and copper ions from an electrolyte onto the cathode surface; during this deposition process, graphene is prone to agglomeration, affecting the composite's electrical and thermal conductivity, and also damaging the graphene... The control of graphene dosage, electrolyte composition, and electrochemical conditions requires high precision. Chemical vapor deposition (CVD) generates graphene in situ on a copper substrate at high temperatures through a chemical reaction, producing composite materials. However, CVD requires high-temperature and vacuum environments, making the conditions harsh, the process complex, and the cost high. Furthermore, the high-temperature conditions of CVD can easily trigger copper-carbon interfacial reactions, forming brittle copper carbide and weakening interfacial toughness. In powder metallurgy, due to the large density difference between graphene and copper powder, graphene is prone to agglomeration, making it difficult to ensure uniform dispersion, and micropores often appear in the composite material. In addition, the interfacial bonding between graphene and the copper substrate in the composite material is weak, easily leading to localized stress concentration or breakage of conductive / thermal pathways, affecting the overall performance of the material.
[0004] Therefore, it is necessary to provide a method for preparing graphene-copper-based composite materials, which can effectively improve the uniformity of graphene distribution, simplify the preparation process, reduce the requirements, and thus improve the comprehensive properties of the composite material, such as mechanical properties, electrical conductivity, and thermal conductivity. Summary of the Invention
[0005] To overcome the problems in the prior art, this invention utilizes the free diffusion of graphene dispersion combined with stacking, cold pressing, and hot pressing processes to prepare graphene-copper matrix composites. This improves the uniform distribution of graphene in the copper matrix and enhances the interfacial bonding strength between graphene and the copper matrix, thereby allowing the reinforcing effect of graphene to be fully utilized and effectively improving the mechanical, electrical, and thermal properties of the composite material.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention proposes a method for preparing a graphene-copper-based composite material, the method comprising the following steps: (1) Surface pretreatment of copper foil.
[0007] (2) The graphene dispersion is dropped onto the surface of the copper foil after the pretreatment in step (1). The graphene dispersion diffuses freely on the surface of the copper foil until it covers the surface of the copper foil. Then the copper foil is dried.
[0008] (3) The copper foil dried in step (2) is stacked in such a way that there is a graphene layer between the two copper foils, and then cold pressing and hot pressing are performed in sequence to obtain the hot-pressed composite material.
[0009] (4) Anneal the hot-pressed composite material in step (3) to obtain the annealed composite material.
[0010] (5) The annealed composite material in step (4) is cold rolled to obtain the rolled composite material.
[0011] (6) Anneal the rolled composite material in step (5) to obtain a graphene copper-based composite material.
[0012] Preferably, the pretreatment process in step (1) includes: first, polishing the surface of the copper foil, then using dilute hydrochloric acid to remove the oxide layer on the surface of the copper foil, and then immersing the copper foil in anhydrous ethanol for ultrasonic treatment.
[0013] During the pretreatment process, the ultrasonic treatment frequency is 40~80kHz and the ultrasonic treatment time is 10~30min.
[0014] Preferably, in step (2), the preparation process of the graphene dispersion includes: dissolving graphene and dispersant in anhydrous ethanol, ultrasonically dispersing and settling the solution in sequence, repeating the ultrasonic dispersion and settling process, and taking the upper suspension as the graphene dispersion.
[0015] Preferably, the dispersant is sodium dodecyl sulfonate, the solid-liquid ratio of graphene to anhydrous ethanol is graphene:anhydrous ethanol = 1g:5000ml, and the solid-liquid ratio of dispersant to anhydrous ethanol is dispersant:anhydrous ethanol = 1g:50000ml.
[0016] Preferably, the solution is ultrasonically dispersed for 30 minutes at a frequency of 40~80kHz, then allowed to stand for 5 minutes. This ultrasonic dispersion and standing process is repeated 4 times.
[0017] Preferably, in step (3), the cold pressing pressure is 40t and the cold pressing time is 0.5h.
[0018] Preferably, in step (3), the hot pressing pressure is 50t, the hot pressing temperature is 400-500℃, and the hot pressing time is 2h.
[0019] Preferably, in steps (4) and (6), the annealing temperature is 250~400℃, the holding time is 10~90min, and the heating rate is 5~25℃.
[0020] By controlling the heating rate between 5 and 25°C, it is possible to effectively avoid thermal stress concentration caused by excessively rapid heating or low efficiency caused by excessively slow heating.
[0021] Preferably, in step (5), the cold rolling deformation is 20%.
[0022] Preferably, the graphene is either two-dimensional graphene or three-dimensional graphene.
[0023] The beneficial effects of this invention are: 1. This invention effectively improves the uniform distribution of graphene in the copper matrix by adding graphene dispersion to the surface of copper foil and combining it with processes such as lamination, annealing, and rolling. This enhances the interfacial bonding strength between graphene and the copper matrix and improves the mechanical, electrical, and thermal properties of the composite material.
[0024] 2. This invention forms a graphene layer by freely diffusing graphene droplets onto the surface of a copper foil. Compared to coating the graphene layer by spraying, this method effectively reduces the "coffee ring" effect, thereby reducing the difference in evaporation rate between the droplet edge and the center. This reduces the problem of uneven ring precipitation caused by graphene accumulation at the droplet boundary. At the same time, it reduces structural disturbance, reduces the destructive effect of high-speed impacts on the graphene structure, and reduces the probability of secondary agglomeration of graphene due to multiple droplet overlap. Compared to chemical vapor deposition, it avoids copper-carbon interface reactions caused by high-temperature environments, thus preventing the formation of brittle carbides.
[0025] 3. This invention uses anhydrous ethanol as a solvent for graphene dispersant. Taking advantage of the high volatility of anhydrous ethanol, liquid-solid and gas-liquid interfaces are formed during dropwise addition. Under the synergistic effect of the surface tension of the two interfaces, graphene undergoes a slow in-situ self-assembly process, which promotes graphene to be more regularly arranged and improves the consistency of composite material performance enhancement.
[0026] 4. This invention effectively eliminates interlayer oxygen and other substances by combining cold pressing with hot pressing, which is beneficial to improving the interfacial bonding performance between graphene and the copper matrix, thereby promoting the graphene to exert its strengthening effect more fully.
[0027] 5. The process of this invention is relatively simple, easy to operate and easy to control. The composite material has excellent mechanical, electrical and thermal properties, making it suitable for industrial application. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the process flow of the present invention; Figure 2 The stress-strain curves of the composite materials prepared in Examples 1-6 of this invention are shown. Detailed Implementation
[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.
[0030] Unless otherwise specified, all chemical reagents used in the embodiments and comparative examples of this invention were commercially available analytical grade reagents.
[0031] In the embodiments and comparative examples of this invention, the copper foil is a small circular piece with a diameter of 25 mm.
[0032] Example 1 This embodiment uses two-dimensional graphene to prepare a graphene-copper-based composite material using the following method: (1) First, polish the surface of the copper foil with sandpaper, then use 10% dilute hydrochloric acid to remove the oxide layer on the surface of the copper foil. After that, immerse the copper foil in a beaker containing anhydrous ethanol, place the beaker in an ultrasonic instrument, and ultrasonically treat it at a frequency of 60kHz for 20 minutes.
[0033] (2) Weigh 0.02g of two-dimensional graphene and 0.002g of sodium dodecyl sulfonate. Add the two-dimensional graphene and sodium dodecyl sulfonate to 100ml of anhydrous ethanol. Disperse the solution by ultrasonication at 60kHz for 30min, let it stand for 5min, and then perform ultrasonic dispersion and stand again. Repeat this process 4 times to obtain a graphene dispersion.
[0034] (3) The graphene dispersion is dropped onto the surface of the pretreated copper foil. The graphene dispersion diffuses freely on the surface of the copper foil until it covers the surface of the copper foil. Then the copper foil is dried. (4) The dried copper foils were stacked in such a way that there was a graphene layer between the two copper foils, for a total of 19 layers. The top was covered with a copper foil without graphene. Then, the stacked objects were cold-pressed at 40t for 0.5h, and then hot-pressed at 400℃ and 50t for 2h to obtain the hot-pressed composite material.
[0035] (5) Heat the hot-pressed composite material to 400°C at a heating rate of 10°C / min, hold for 60 min, and anneal to obtain the annealed composite material.
[0036] (6) The annealed composite material is cold rolled with the deformation controlled at 20% to obtain the rolled composite material.
[0037] (7) The rolled composite material was heated to 400℃ at a heating rate of 10℃ / min and held for 60min to obtain the graphene copper-based composite material.
[0038] The copper-based composite material prepared in this embodiment is designated as 400℃ [Cu / 2D-Gr / Cu]. 20 .
[0039] Example 2 This embodiment uses the same method as Example 1 to prepare graphene copper-based composite material, the difference being that the hot-pressing temperature in this embodiment is 450℃.
[0040] The copper-based composite material prepared in this embodiment is designated as 450℃ [Cu / 2D-Gr / Cu]. 20 .
[0041] Example 3 This embodiment uses the same method as Example 1 to prepare graphene copper-based composite material, the difference being that the hot-pressing temperature in this embodiment is 500℃.
[0042] The copper-based composite material prepared in this embodiment is designated as 500℃ [Cu / 2D-Gr / Cu]. 20 .
[0043] Example 4 This embodiment uses the same method as Example 1 to prepare graphene copper-based composite material, the difference being that this embodiment uses three-dimensional graphene.
[0044] The copper-based composite material prepared in this embodiment is designated as 400℃ [Cu / 3D-Gr / Cu]. 20 .
[0045] Example 5 This embodiment uses the same method as Example 2 to prepare graphene copper-based composite material, the difference being that this embodiment uses three-dimensional graphene.
[0046] The copper-based composite material prepared in this embodiment is designated as 450℃ [Cu / 3D-Gr / Cu]. 20 .
[0047] Example 6 This embodiment uses the same method as Example 3 to prepare graphene copper-based composite material, the difference being that this embodiment uses three-dimensional graphene.
[0048] The copper-based composite material prepared in this embodiment is designated as 500℃ [Cu / 3D-Gr / Cu]. 20 .
[0049] Example 7 This embodiment uses two-dimensional graphene to prepare a graphene-copper-based composite material using the following method: (1) First, use 10% dilute hydrochloric acid to remove the oxide layer on the surface of the copper foil. Then, polish the surface of the copper foil with sandpaper. After that, immerse the copper foil in a beaker containing anhydrous ethanol and place the beaker in an ultrasonic instrument. Sonicate at 40kHz for 30 minutes.
[0050] (2) Weigh 0.02g of two-dimensional graphene and 0.002g of sodium dodecyl sulfonate. Add the two-dimensional graphene and sodium dodecyl sulfonate to 100ml of anhydrous ethanol. After ultrasonic dispersion of the solution at 40kHz for 30min, let it stand for 5min. Repeat this process 4 times to obtain graphene dispersion.
[0051] (3) The graphene dispersion is dropped onto the surface of the pretreated copper foil. The graphene dispersion diffuses freely on the surface of the copper foil until it covers the surface of the copper foil. Then the copper foil is dried. (4) The dried copper foils were stacked in such a way that there was a graphene layer between the two copper foils, for a total of 19 layers. The top was covered with a copper foil without graphene. Then, the stacked objects were cold-pressed at 40t for 0.5h, and then hot-pressed at 400℃ and 50t for 2h to obtain the hot-pressed composite material.
[0052] (5) Heat the hot-pressed composite material to 250°C at a heating rate of 5°C / min, hold for 90 min, and anneal to obtain the annealed composite material.
[0053] (6) The annealed composite material is cold rolled with the deformation controlled at 20% to obtain the rolled composite material.
[0054] (7) The rolled composite material was heated to 250°C at a heating rate of 5°C / min and held for 90 min to obtain the graphene copper-based composite material.
[0055] The graphene-copper composite material of this embodiment has similar properties to that of Example 1.
[0056] Example 8 This embodiment uses three-dimensional graphene to prepare a graphene-copper-based composite material using the following method: (1) First, use 10% dilute hydrochloric acid to remove the oxide layer on the surface of the copper foil. Then, polish the surface of the copper foil with sandpaper. After that, immerse the copper foil in a beaker containing anhydrous ethanol and place the beaker in an ultrasonic instrument. Sonicate at 80kHz for 10 minutes.
[0057] (2) Weigh 0.02g of two-dimensional graphene and 0.002g of sodium dodecyl sulfonate. Add the two-dimensional graphene and sodium dodecyl sulfonate to 100ml of anhydrous ethanol. Disperse the solution by ultrasonication at 80kHz for 30min, let it stand for 5min, and then perform ultrasonic dispersion and stand again. Repeat this process 4 times to obtain a graphene dispersion.
[0058] (3) The graphene dispersion is dropped onto the surface of the pretreated copper foil. The graphene dispersion diffuses freely on the surface of the copper foil until it covers the surface of the copper foil. Then the copper foil is dried. (4) The dried copper foils were stacked in such a way that there was a graphene layer between the two copper foils, for a total of 19 layers. The top was covered with a copper foil without graphene. Then, the stacked objects were cold-pressed at 40t for 0.5h, and then hot-pressed at 400℃ and 50t for 2h to obtain the hot-pressed composite material.
[0059] (5) Heat the hot-pressed composite material to 350°C at a heating rate of 25°C / min, hold for 10 min, and anneal to obtain the annealed composite material.
[0060] (6) The annealed composite material is cold rolled with the deformation controlled at 20% to obtain the rolled composite material.
[0061] (7) The rolled composite material was heated to 350°C at a heating rate of 25°C / min and held for 10 min to obtain the graphene copper-based composite material.
[0062] The graphene-copper composite material in this embodiment has similar properties to that in Example 4.
[0063] Comparative Example 1 The graphene-copper composite material in this comparative example was prepared using the same method as in Example 1. The difference is that the graphene dispersion was sprayed onto the copper foil surface using a spraying method.
[0064] Compared with Example 1, the interfacial bonding strength and overall performance uniformity of the composite material in this comparative example are reduced to a certain extent. During the spraying process, the high-speed impact of droplets on the copper foil surface can easily cause local damage and interfacial disturbance to the graphene structure. At the same time, it can easily lead to the "coffee ring effect", causing graphene to accumulate at the edge of the droplets and form an uneven distribution.
[0065] Comparative Example 2 This comparative example uses the same method as Example 1 to prepare graphene copper-based composite material, the difference being that: this comparative example uses chemical vapor deposition to grow graphene in situ on copper foil.
[0066] Compared with the composite material of Example 1, the overall performance of this comparative example decreased to a certain extent because the copper-carbon interface reaction is easily triggered during the chemical vapor deposition process, forming a brittle copper carbide phase.
[0067] Comparative Example 3 This comparative example uses the same method as Example 1 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0068] Comparative Example 4 This comparative example uses the same method as Example 2 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0069] Comparative Example 5 This comparative example uses the same method as Example 3 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0070] Comparative Example 6 This comparative example uses the same method as Example 4 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0071] Comparative Example 7 This comparative example uses the same method as Example 5 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0072] Comparative Example 8 This comparative example uses the same method as Example 6 to prepare graphene copper-based composite materials, except that the rolled composite material is not annealed in this comparative example.
[0073] The mechanical properties, electrical conductivity, and thermal conductivity of the graphene-copper matrix composites prepared in Examples 1-6 were tested. The mechanical property test results are as follows: Figure 2 As shown, through Figure 2 The quantitative results are shown in Table 1, the hardness test results are shown in Table 2, the electrical conductivity test results are shown in Table 3, and the thermal conductivity test results are shown in Table 4.
[0074] Table 1 Table 2 Table 3 Table 4 As can be seen from the performance data in Tables 1-4, the graphene copper-based composite material prepared by the present invention has excellent comprehensive properties in terms of mechanical, thermal, and electrical properties. In particular, the comparison between Examples 1-6 and Comparative Examples 3-8 (Table 3) shows that the present invention effectively improves the electrical conductivity of the graphene copper-based composite material by annealing after rolling.
[0075] In summary, this invention utilizes the free diffusion of graphene dispersion combined with layered stacking, pressing, annealing, rolling, and then annealing processes to promote uniform and good dispersion of graphene in a copper matrix, allowing graphene to better exert its strengthening effect and thus improving the comprehensive performance of the composite material in many aspects.
[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. A method for preparing a graphene-copper-based composite material, characterized in that: The preparation method includes the following steps: (1) Surface pretreatment of copper foil; (2) The graphene dispersion is dropped onto the surface of the copper foil after the pretreatment in step (1). The graphene dispersion diffuses freely on the surface of the copper foil until it covers the surface of the copper foil. Then the copper foil is dried. (3) The copper foil dried in step (2) is stacked in such a way that there is a graphene layer between the two copper foils, and then cold pressing and hot pressing are performed in sequence to obtain the hot-pressed composite material. (4) Anneal the hot-pressed composite material in step (3) to obtain the annealed composite material; (5) The annealed composite material in step (4) is cold rolled to obtain the rolled composite material; (6) Anneal the rolled composite material in step (5) to obtain a graphene copper-based composite material.
2. The preparation method according to claim 1, characterized in that: In step (1), the specific pretreatment process includes: first, polishing the surface of the copper foil, then using dilute hydrochloric acid to remove the oxide layer on the surface of the copper foil, and then immersing the copper foil in anhydrous ethanol for ultrasonic treatment.
3. The preparation method according to claim 1, characterized in that: In step (2), the preparation process of the graphene dispersion includes: dissolving graphene and dispersant in anhydrous ethanol, ultrasonically dispersing and settling the solution in sequence, repeating the ultrasonic dispersion and settling process, and taking the upper suspension as the graphene dispersion.
4. The preparation method according to claim 3, characterized in that: The dispersant is sodium dodecyl sulfonate, the solid-liquid ratio of graphene to anhydrous ethanol is graphene:anhydrous ethanol = 1g:5000ml, and the solid-liquid ratio of dispersant to anhydrous ethanol is dispersant:anhydrous ethanol = 1g:50000ml.
5. The preparation method according to claim 3, characterized in that: After ultrasonically dispersing the solution for 30 minutes at a frequency of 40~80kHz, let it stand for 5 minutes. Repeat the ultrasonic dispersion and standing process 4 times.
6. The preparation method according to claim 1, characterized in that: In step (3), the cold pressing pressure is 40t and the cold pressing time is 0.5h.
7. The preparation method according to claim 1, characterized in that: In step (3), the hot pressing pressure is 50t, the hot pressing temperature is 400-500℃, and the hot pressing time is 2h.
8. The preparation method according to claim 1, characterized in that: In steps (4) and (6), the annealing temperature is 250~400℃, the holding time is 10~90min, and the heating rate is 5~25℃.
9. The preparation method according to claim 1, characterized in that: In step (5), the cold rolling deformation is 20%.
10. The preparation method according to any one of claims 1-9, characterized in that: The graphene is either two-dimensional graphene or three-dimensional graphene.