A copper graphene composite material and a preparation method thereof

Abstract

The application provides a preparation method of a copper graphene composite material, comprising the following steps: a) mixing copper, manganese and carbon raw materials according to a proportion, then performing smelting, and pouring to obtain a copper-manganese-carbon ternary alloy ingot; b) placing the ingot obtained in the step a) under a vacuum condition to perform heat treatment, decomposing Mn3C phases in the alloy, generating graphene in situ, and obtaining an intermediate product; and c) performing high-temperature treatment on the intermediate product obtained in the step b) under a vacuum condition, removing residual manganese, and obtaining the copper graphene composite material. The application can solve the technical problems of uneven dispersion of graphene, poor interface combination, complex process, high cost and the like in the prior art. In addition, the application further provides a copper graphene composite material.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite material preparation technology, and in particular to a copper-graphene composite material and its preparation method. Background Technology

[0002] Graphene possesses excellent mechanical, electrical, and thermal conductivity, making it an ideal reinforcement for copper-based composites. However, graphene has a large specific surface area, is prone to agglomeration, and exhibits a significant density difference with the copper matrix, making it difficult to achieve uniform dispersion of graphene in copper using traditional casting methods. While powder metallurgy can partially solve the dispersion problem, it suffers from long processes, high costs, and insufficient interfacial bonding strength between graphene and copper, hindering the full realization of its reinforcing effect. Chemical vapor deposition (CVD) can produce high-quality graphene, but the equipment is expensive and inefficient, making large-scale production difficult.

[0003] Therefore, it is of great significance to develop a low-cost, high-efficiency method for preparing copper-graphene composite materials with uniform graphene dispersion and good interfacial bonding. Summary of the Invention

[0004] The purpose of this invention is to provide a copper-graphene composite material and its preparation method that solves the technical problems of uneven graphene dispersion, poor interfacial bonding, complex process and high cost in the prior art.

[0005] The technical solution adopted by this invention to solve its technical problem is: In a first aspect, the present invention provides a method for preparing a copper-graphene composite material, comprising the following steps: a) Mix copper, manganese and carbon raw materials in a certain proportion and then melt them to obtain copper-manganese-carbon ternary alloy ingots. b) The ingot obtained in step a) is subjected to heat treatment under vacuum conditions to decompose the Mn3C phase in the alloy and generate graphene in situ, thus obtaining an intermediate product. c) The intermediate product obtained in step b) is subjected to high temperature treatment under vacuum conditions to remove residual manganese and obtain copper graphene composite material. d) The copper-graphene composite material obtained in step c) is subjected to plastic molding and then annealed in an inert atmosphere to obtain the copper-graphene composite material product.

[0006] Furthermore, the mass percentage of the raw materials in step a) is: 5.0%~15.0% manganese, 0.5%~3.0% carbon, and the balance being copper; preferably 8.0%~12.0% manganese, 1.0%~2.5% carbon, and the balance being copper.

[0007] Furthermore, the melting temperature in step a) is 1200℃~1350℃, the holding time is 30~60 minutes, and it is carried out under an argon protective atmosphere or vacuum conditions.

[0008] Furthermore, before proceeding to step b), the ingot in step a) is first machined to remove the surface oxide scale and processed into blocks, plates, or chips with a thickness of 3-10 mm.

[0009] Furthermore, the vacuum degree of the vacuum heat treatment in step b) is ≤1×10⁻⁶. -2 Pa, preferably ≤1×10 -3 Pa; heating rate is 5~15℃ / min, heat treatment temperature is 700℃~950℃, and holding time is 2~8 hours.

[0010] Furthermore, in step b), when the heat treatment temperature is 700℃~750℃, the number of graphene layers obtained is 1~5; when the heat treatment temperature is 750℃~850℃, the number of graphene layers obtained is 3~8; and when the heat treatment temperature is 850℃~950℃, the number of graphene layers obtained is 5~15.

[0011] Furthermore, the vacuum degree of the high-temperature treatment in step c) is ≤1×10⁻⁶. -2 Pa, the treatment temperature is 950℃~1080℃, and the holding time is 2~4 hours.

[0012] Furthermore, the processing temperature in step c) is lower than the melting point of copper, 1083°C, to avoid melting of the copper substrate. Furthermore, step c) is followed by a post-processing step of rolling, drawing, or annealing the product.

[0013] Secondly, the present invention also provides a copper-graphene composite material prepared by any of the preparation methods described above, wherein the conductivity of the composite material is >106% IACS.

[0014] In summary, the beneficial effects of the present invention are as follows: The copper-graphene composite material and its preparation method of the present invention have the following characteristics: (1) Graphene is generated in situ inside the copper matrix through the decomposition of Mn3C, which avoids the problems of graphene agglomeration and floating in traditional methods, and the dispersion uniformity is significantly better than that of mechanical mixing method; (2) The graphene generated in situ forms an atomic-level bonding interface with the copper matrix, resulting in high electron transport and load transfer efficiency, and the conductivity and mechanical properties of the composite material are improved simultaneously. (3) Using conventional smelting and vacuum heat treatment equipment, the process flow is short and the operation window is wide, making it easy to achieve industrial mass production, and the cost is lower than that of CVD method; (4) By adjusting the heat treatment temperature and time, the number of graphene layers, size and crystallinity can be effectively controlled to meet the performance requirements of different application scenarios. (5) The manganese removed by volatilization can be recovered by condensation, realizing resource recycling and meeting the requirements of green manufacturing; (6) The conductivity of the resulting composite material is higher than that of pure copper, reaching 106%~110% IACS. Detailed Implementation

[0015] The present invention will now be described in further detail.

[0016] In a first aspect, the present invention provides a method for preparing a copper-graphene composite material, comprising the following steps: a) Mix copper, manganese and carbon raw materials in a certain proportion and then melt them to obtain copper-manganese-carbon ternary alloy ingots. b) The ingot obtained in step a) is subjected to heat treatment under vacuum conditions to decompose the Mn3C phase in the alloy and generate graphene in situ, thus obtaining an intermediate product. c) The intermediate product obtained in step b) is subjected to high temperature treatment under vacuum conditions to remove residual manganese, thereby obtaining a copper-graphene composite material.

[0017] Furthermore, the mass percentage of the raw materials in step a) is: manganese 5.0%~15.0%, carbon 0.5%~3.0%, and the balance is copper.

[0018] Furthermore, in step a), the melting temperature is 1200℃~1350℃, the holding time is 30~60 minutes, the process is carried out under an argon protective atmosphere or vacuum conditions, and electromagnetic stirring is applied.

[0019] Furthermore, before proceeding to step b), the ingot obtained in step a) is first machined to form a block with a thickness of 3-10 mm.

[0020] Furthermore, the vacuum degree of the vacuum heat treatment in step b) is ≤1×10⁻⁶. -2 Pa, heating rate of 5~15℃ / min, heat treatment temperature of 700℃~950℃, holding time of 2~8 hours.

[0021] Furthermore, the vacuum degree of the vacuum heat treatment in step b) is ≤1×10⁻⁶. -3 Pa.

[0022] Furthermore, when the heat treatment temperature is 700℃~750℃, the number of graphene layers obtained is 1~5; when the heat treatment temperature is 750℃~850℃, the number of graphene layers obtained is 3~8; and when the heat treatment temperature is 850℃~950℃, the number of graphene layers obtained is 5~15.

[0023] Furthermore, the vacuum degree of the high-temperature treatment in step c) is ≤1×10⁻⁶. -2Pa, the treatment temperature is 950℃~1080℃, and the holding time is 2~4 hours.

[0024] Furthermore, it also includes the step of plastic molding and / or annealing the composite material obtained in step c).

[0025] Specifically, the raw materials in step a) are as follows by mass percentage: manganese 5.0%~15.0%, carbon 0.5%~3.0%, with the balance being copper; preferably, the manganese content is 8.0%~12.0%, and the carbon content is 1.0%~2.5%. High-purity copper ≥99.95%, high-purity manganese ≥99.9%, and high-purity carbon (graphite powder, carbon black, or intermediate carbon source) ≥99.5%. A non-vacuum medium-frequency furnace is used for smelting, and high-purity nitrogen or argon (≥99.5%) is continuously introduced during the smelting process as a protective atmosphere to prevent oxidation and burn-off of manganese and carbon. The smelting temperature is 1200℃~1350℃, and the holding time is 30~60 minutes. During this time, electromagnetic stirring or mechanical stirring can be used to ensure uniform alloy composition. After holding, the alloy melt is poured into a water-cooled copper mold or graphite mold and rapidly cooled to obtain a copper-manganese-carbon master alloy ingot.

[0026] The vacuum conditions described in step b) require the furnace internal pressure to be ≤1×10⁻⁶. -2 Pa (preferably ≤1×10) -3 The heat treatment involves heating to 700℃~950℃ (preferably 750℃~850℃) at a heating rate of 5~15℃ / min, and holding for 2~8 hours (preferably 3~6 hours). After holding, the furnace is cooled to room temperature.

[0027] The high-temperature treatment in step c) is ≥950℃ (preferably 1000℃~1080℃) and the vacuum degree is ≤1×10 -2 Under Pa conditions, continue the heat treatment for 2-4 hours. Cool the furnace or argon charge to room temperature, then remove the product.

[0028] The annealing in step d) is carried out in an inert atmosphere (argon or nitrogen, 500℃~700℃) to eliminate work hardening and further optimize electrical conductivity.

[0029] In a second aspect, the present invention provides a copper-graphene composite material prepared by any one of the methods described above, wherein the conductivity of the composite material is greater than 106% IACS (typical value range 106%~110% IACS, fluctuating depending on the number of graphene layers and residual manganese content). Example 1

[0030] (1) Weigh by mass percentage: 8.0% manganese, 1.2% carbon, and the balance is copper (copper purity ≥99.95%, manganese purity ≥99.9%, carbon purity ≥99.5%).

[0031] (2) Place the raw material into a medium-frequency induction melting furnace, introduce argon gas for protection, heat to 1250℃, hold for 40 minutes, stir electromagnetically, and pour into a water-cooled copper mold to obtain a copper-manganese-carbon alloy ingot. Machin the ingot into a block with a thickness of 5mm.

[0032] (3) Place the above-mentioned block alloy in a vacuum heat treatment furnace and evacuate it to a vacuum level of 1×10⁻⁶. -3 Pa was heated to 800℃ at a rate of 10℃ / min, held at that temperature for 5 hours, and then cooled in the furnace to obtain the intermediate product.

[0033] (4) Place the intermediate products in the same furnace and maintain a vacuum degree ≤1×10 -2 Pa, heated to 1050℃, held for 3 hours, and then cooled to room temperature with argon to obtain copper-graphene composite material.

[0034] The material was tested and found to have a conductivity of 108% IACS (tested using the four-probe method according to the international standard for annealed copper), and it has approximately 5 to 6 graphene layers that are evenly distributed within the copper substrate. Example 2

[0035] (1) Weigh by mass percentage: 12.0% manganese, 2.0% carbon, and the balance is copper (copper purity ≥ 99.95%, manganese purity ≥ 99.9%, carbon purity ≥ 99.5%).

[0036] (2) Place the raw material into a medium-frequency induction melting furnace, introduce argon gas for protection, heat to 1300℃, hold for 50 minutes, stir electromagnetically, and pour into a water-cooled copper mold to obtain a copper-manganese-carbon alloy ingot. Machin the ingot into a block with a thickness of 8mm.

[0037] (3) Place the above-mentioned block alloy in a vacuum heat treatment furnace and evacuate it to a vacuum level of 1×10⁻⁶. -3 Pa was heated to 750°C at a rate of 10°C / min, held at that temperature for 6 hours, and then cooled in the furnace to obtain the intermediate product.

[0038] (4) Place the intermediate products in the same furnace and maintain a vacuum degree ≤1×10 -2 Pa was heated to 1020℃, held for 4 hours, and then cooled to room temperature with argon to obtain a copper-graphene composite material.

[0039] The material was tested and found to have a conductivity of 107% IACS (tested using the four-probe method according to the international standard for annealed copper), and it has approximately 3 to 5 graphene layers that are evenly distributed in the copper matrix. Example 3

[0040] (1) Weigh out the following by mass percentage: 10.0% manganese, 1.5% carbon, and the balance is copper (copper purity ≥ 99.95%, manganese purity ≥ 99.9%, carbon purity ≥ 99.5%).

[0041] (2) Place the raw material into a medium-frequency induction melting furnace, introduce argon gas for protection, heat to 1280℃, hold for 45 minutes, stir electromagnetically, and pour into a water-cooled copper mold to obtain a copper-manganese-carbon alloy ingot. Machin the ingot into a block with a thickness of 3mm.

[0042] (3) Place the above-mentioned block alloy in a vacuum heat treatment furnace and evacuate it to a vacuum level of 5×10⁻⁶. -3 Pa was heated to 850°C at a rate of 10°C / min, held at that temperature for 3 hours, and then cooled in the furnace to obtain the intermediate product.

[0043] (4) Place the intermediate products in the same furnace, maintaining a vacuum degree ≤1×10 -2 Pa was heated to 1070℃, held at that temperature for 2.5 hours, and then cooled to room temperature with argon to obtain a copper-graphene composite material.

[0044] The material was tested and found to have a conductivity of 106.5% IACS (tested using the four-probe method according to the international standard for annealed copper), and approximately 8 to 10 graphene layers, which are uniformly distributed in the copper substrate. Example 4

[0045] (1) Weigh by mass percentage: 5.0% manganese, 0.5% carbon, and the balance is copper (copper purity ≥99.95%, manganese purity ≥99.9%, carbon purity ≥99.5%).

[0046] (2) Place the raw material into a medium-frequency induction melting furnace, introduce argon gas for protection, heat to 1200℃, hold for 30 minutes, stir electromagnetically, and pour into a water-cooled copper mold to obtain a copper-manganese-carbon alloy ingot. Machin the ingot into a block with a thickness of 10mm.

[0047] (3) Place the above-mentioned block alloy in a vacuum heat treatment furnace and evacuate it to a vacuum level of 1×10⁻⁶. -2 Pa was heated to 700℃ at a rate of 10℃ / min, held at that temperature for 8 hours, and then cooled in the furnace to obtain the intermediate product.

[0048] (4) Place the intermediate products in the same furnace, maintaining a vacuum degree ≤1×10 -2 Pa, heated to 950℃, held for 4 hours, and then cooled to room temperature with argon to obtain copper-graphene composite material.

[0049] The material was tested and found to have a conductivity of 106.2% IACS (tested using the four-probe method according to the international standard for annealed copper), and it has approximately 1 to 3 graphene layers that are evenly distributed in the copper matrix. Example 5

[0050] (1) Weigh by mass percentage: 15.0% manganese, 3.0% carbon, and the balance is copper (copper purity ≥99.95%, manganese purity ≥99.9%, carbon purity ≥99.5%).

[0051] (2) Place the raw material into a medium-frequency induction melting furnace, introduce argon gas for protection, heat to 1350℃, hold for 60 minutes, stir electromagnetically, and pour into a water-cooled copper mold to obtain a copper-manganese-carbon alloy ingot. Machin the ingot into a block with a thickness of 3mm.

[0052] (3) Place the above-mentioned block alloy in a vacuum heat treatment furnace and evacuate it to a vacuum level of 1×10⁻⁶. -3 Pa was heated to 950°C at a rate of 10°C / min, held at that temperature for 2 hours, and then cooled in the furnace to obtain the intermediate product.

[0053] (4) Place the intermediate products in the same furnace, maintaining a vacuum degree ≤1×10 -2 Pa was heated to 1075℃, held for 2 hours, and then cooled to room temperature with argon to obtain a copper-graphene composite material.

[0054] The material was tested and found to have a conductivity of 106.8% IACS (tested using the four-probe method according to the international standard for annealed copper), and approximately 10 to 15 graphene layers, which are uniformly distributed in the copper substrate.

[0055] The properties of the copper-graphene composite materials obtained in the above embodiments are listed in Table 1: Table 1 Performance Comparison of Examples

[0056] The copper-graphene composite material and its preparation method of the present invention have the following characteristics: (1) Graphene is generated in situ inside the copper matrix through the decomposition of Mn3C, which avoids the problems of graphene agglomeration and floating in traditional methods, and the dispersion uniformity is significantly better than that of mechanical mixing method; (2) The graphene generated in situ forms an atomic-level bonding interface with the copper matrix, resulting in high electron transport and load transfer efficiency, and the conductivity and mechanical properties of the composite material are improved simultaneously. (3) Using conventional smelting and vacuum heat treatment equipment, the process flow is short and the operation window is wide, making it easy to achieve industrial mass production, and the cost is lower than that of CVD method; (4) By adjusting the heat treatment temperature and time, the number of graphene layers, size and crystallinity can be effectively controlled to meet the performance requirements of different application scenarios. (5) The manganese removed by volatilization can be recovered by condensation, realizing resource recycling and meeting the requirements of green manufacturing; (6) The conductivity of the resulting composite material is higher than that of pure copper, reaching 106%~110% IACS.

[0057] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any other way. Any person skilled in the art may make changes or equivalent variations to the disclosed technical content and apply them to other fields. However, any simple modifications, equivalent variations, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood through specific circumstances.

Claims

1. A method for preparing a copper-graphene composite material, characterized in that, Includes the following steps: a) Mix copper, manganese and carbon raw materials in a certain proportion and then melt them to obtain copper-manganese-carbon ternary alloy ingots. b) The ingot obtained in step a) is subjected to heat treatment under vacuum conditions to decompose the Mn3C phase in the alloy and generate graphene in situ, thus obtaining an intermediate product. c) The intermediate product obtained in step b) is subjected to high temperature treatment under vacuum conditions to remove residual manganese, thereby obtaining a copper-graphene composite material.

2. The method for preparing the copper-graphene composite material according to claim 1, characterized in that, The raw materials in step a) are: manganese 5.0%~15.0%, carbon 0.5%~3.0%, and the balance is copper.

3. The method for preparing the copper-graphene composite material according to claim 1 or 2, characterized in that, The melting temperature in step a) is 1200℃~1350℃, the holding time is 30~60 minutes, and it is carried out under an argon protective atmosphere or vacuum conditions, with electromagnetic stirring applied.

4. The method for preparing the copper-graphene composite material according to claim 1, characterized in that, Before proceeding to step b), the ingot obtained in step a) is first machined to form a block with a thickness of 3-10 mm.

5. The method for preparing the copper-graphene composite material according to claim 1, characterized in that, The vacuum degree of the vacuum heat treatment in step b) is ≤1×10 -2 Pa, heating rate of 5~15℃ / min, heat treatment temperature of 700℃~950℃, holding time of 2~8 hours.

6. The method for preparing the copper-graphene composite material according to claim 5, characterized in that, The vacuum degree of the vacuum heat treatment in step b) is ≤1×10 -3 Pa.

7. The method for preparing the copper-graphene composite material according to claim 5, characterized in that, When the heat treatment temperature is 700℃~750℃, the number of graphene layers obtained is 1~5; when the heat treatment temperature is 750℃~850℃, the number of graphene layers obtained is 3~8; when the heat treatment temperature is 850℃~950℃, the number of graphene layers obtained is 5~15.

8. The method for preparing the copper-graphene composite material according to claim 1, characterized in that, The vacuum degree of the high-temperature treatment in step c) is ≤1×10 -2 Pa, the treatment temperature is 950℃~1080℃, and the holding time is 2~4 hours.

9. The method for preparing the copper-graphene composite material according to claim 1, characterized in that, It also includes the steps of plastic molding and / or annealing the composite material obtained in step c).

10. A copper-graphene composite material prepared by the method according to any one of claims 1 to 9, characterized in that: The electrical conductivity of the composite material is greater than 106% IACS.

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