Copper-based graphene composite wire and preparation process thereof

Abstract

The invention provides a copper-based graphene composite wire and a preparation process thereof, and belongs to the field of metal composite materials. The preparation process comprises the steps of in-situ growth, ball milling, continuous extrusion, multi-pass continuous extrusion, primary annealing treatment, cold drawing and secondary annealing treatment. Graphene is evenly distributed in a matrix through the processes of in-situ growth, ball milling, multi-pass continuous extrusion, cold drawing and the like, the size of graphene in the matrix ranges from 10 nm to 20 nm, the average grain size of copper ranges from 1 micrometer to 10 micrometers, the tensile strength is 550 MPa or above, and the electric conductivity is 105% IACS or above. The conductive performance of the copper-based graphene composite wire is improved, and the advantage of continuous machining of the wire is reserved.

Description

Technical Field

[0001] The present invention provides a copper-based graphene composite wire and a preparation process thereof, relating to the field of metal composite materials. Background Art

[0002] Copper is widely used in fields such as wires, transformer windings, and integrated circuits due to its excellent electrical conductivity and processing performance. However, the electrical conductivity of pure copper has approached the theoretical limit, and traditional methods can only slightly improve its electrical conductivity, making it difficult to meet the stringent requirements of high electrical conductivity and low signal loss. The research on the high electrical conductivity of copper-based graphene composites aims to address the urgent need for highly efficient conductive materials. As a two-dimensional material, graphene has ultra-high carrier mobility, ultra-high thermal conductivity, and mechanical strength, providing new ideas for the performance breakthrough of copper-based composites.

[0003] The synergistic effect between graphene and copper can significantly improve the electrical conductivity of the composite material. However, in actual research, multiple challenges are faced: weak interfacial bonding between graphene and copper (mainly relying on van der Waals forces), uneven dispersion of graphene, structural damage (such as wrinkles and defects) during the preparation process of the composite material, and high interfacial contact resistance. In existing preparation methods, Yu Zhang et al. [Zhang Y, Li Y, Li Y, et al. Effect of Graphene Content on Microstructure and Properties of Gr / Cu Composites[C] / / Chinese Materials Conference. 2020] used processes such as ball milling + hot pressing sintering to manufacture copper-based graphene composites. Although it can be mass-produced, graphene agglomerates inside the copper matrix during the hot pressing sintering process, significantly reducing the electrical conductivity.

[0004] Therefore, the preparation processes of the above-mentioned copper-based graphene composite wires are all difficult to meet the relevant requirements. Summary of the Invention

[0005] In order to solve the bottleneck problems that generally exist in the prior art, such as limited improvement in electrical conductivity or difficulty in balancing mechanical properties and electrical conductivity, the present invention provides a copper-based graphene composite wire and a preparation process thereof. In the present invention, graphene is uniformly distributed in the matrix through processes such as in-situ growth, ball milling, multi-pass continuous extrusion, and cold drawing. The present invention can not only improve the electrical conductivity of the copper-based graphene composite wire but also retain the advantages of continuous processing of the wire.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A preparation process of a copper-based graphene composite wire, the preparation process includes in-situ growth, ball milling, continuous extrusion, multi-pass continuous extrusion, first annealing treatment, cold drawing and second annealing treatment, specifically including the following steps:

[0008] The first step, in-situ growth:

[0009] Step 1.1, Mix copper powder and a carbon precursor and add them to a solvent to obtain a uniform suspension, where the carbon precursor is α-naphthol;

[0010] Step 1.2, Perform post-treatment on the suspension to obtain copper / α-naphthol powder;

[0011] Step 1.3, Put the coated copper / α-naphthol powder into a quartz tube furnace, and perform graphitization treatment under the atmosphere of hydrogen and argon, the temperature is between 700 °C and 900 °C, and the growth time is 2h - 6h, to obtain copper / graphene composite powder after in-situ growth.

[0012] Further, in the step 1.1, the solvent is ethanol; the size of the copper powder is 50 mesh - 500 mesh. After the copper powder and the carbon precursor are mixed, under mechanical stirring at 200r / min - 450r / min, ultrasonic treatment is performed for 20min - 60min to obtain a suspension. The mass fraction of the carbon precursor added to the copper powder is 0.4wt% - 6wt%.

[0013] Further, in the step 1.2, the post-treatment is specifically: Use a rotary evaporator to treat in an oil bath at 130 °C for 30min - 45min to remove the solvent, and make the carbon precursor uniformly coated on the surface of the copper particulate material to obtain copper / α-naphthol powder.

[0014] The second step, ball milling: Quantitatively mix the copper / graphene composite powder after in-situ growth and pure copper powder, and perform ball milling through a stirred ball mill, where the mass ratio of the copper / graphene composite powder to the pure copper powder is 1:1 - 1:3. Obtain a mixed particulate material with a graphene content of 0.1wt% - 2.5wt%.

[0015] Further, in the second step, the ball milling time is 1h - 4h, and the rotational speed of the ball mill is 200rpm - 500rpm.

[0016] Further, in the second step, petroleum ether is added before ball milling to prevent excessive agglomeration of graphene; argon with a purity of 99.99% is continuously introduced during ball milling to prevent oxidation of the copper powder.

[0017] Step 3, continuous extrusion: Preheat the continuous extrusion die in a box-type resistance furnace, assemble the preheated continuous extrusion die onto the continuous extruder, uniformly pour the mixed granular material into the extrusion cavity of the continuous extruder, with an extrusion speed of 4 r / min - 6 r / min, to obtain a copper-based graphene rod blank with a diameter of 8 mm - 12 mm.

[0018] Further, in the third step, the preheating temperature is 400°C - 600°C and the time is 20 min - 45 min.

[0019] Step 4, multi-pass continuous extrusion: Preheat the continuous extrusion die in a box-type resistance furnace, assemble the heat-insulated continuous extrusion die onto the continuous extruder, and perform multi-pass continuous extrusion on the copper-based graphene rod blank obtained in the third step. The number of extrusion passes is 3 - 10 passes, to obtain a copper-based graphene composite wire with a diameter of 2 mm - 4 mm.

[0020] Further, in the fourth step, the preheating temperature is 400°C - 600°C and the time is 20 min - 45 min.

[0021] Step 5, annealing: Put the copper-based graphene composite wire obtained in the fourth step into an inert gas annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 30 min - 45 min, and the annealing temperature is 300°C - 800°C. After annealing is completed, cool the furnace to room temperature.

[0022] Step 6, cold drawing: Assemble the annealed copper-based graphene composite wire onto a cold drawing machine and perform multi-pass cold drawing to obtain a copper-based graphene composite wire.

[0023] Further, in the sixth step, the surface of the copper-based graphene composite wire needs to be re-coated with drawing lubricant before each pass of cold drawing. The cold drawing ratio for each pass is set at 15% - 25%, and the total cold drawing processing rate is 50% - 99%.

[0024] Step 7, annealing: Put the cold-drawn copper-based graphene composite wire into an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 15 min - 30 min, and the annealing temperature is 300°C - 800°C. After annealing is completed, cool the furnace to room temperature to obtain a copper-based graphene composite wire.

[0025] A copper-based graphene composite wire is prepared by in-situ growth, ball milling, continuous extrusion, multi-pass continuous extrusion, first annealing treatment, cold drawing and second annealing treatment using the above preparation process, and is composed of a copper-based matrix and graphene; the graphene is evenly distributed in the copper matrix, the size of the graphene in the copper matrix is between 10 nm and 20 nm, and the average grain size of the copper is between 1 μm and 10 μm; the tensile strength of the copper-based graphene composite wire is above 550 MPa, and the conductivity is above 105% IACS.

[0026] Compared with the prior art, the preparation process of the copper-based graphene composite wire provided by the present invention has the following advantages:

[0027] (1) In the present invention, the in-situ growth process is used, and a fine and dispersed three-dimensional graphene conductive network is formed in the copper-based body. Further optimizing the dispersibility limits the growth size of the graphene to 10-20 nm, avoiding stress concentration or folding defects caused by over-large lamellae. Compared with traditional copper-based wires, its electrical conductivity is increased by 5%-10%.

[0028] (2) In the present invention, the multi-pass continuous extrusion process is used. During each extrusion process, the copper matrix undergoes severe plastic deformation and dynamic recrystallization, and the grains are elongated to form fine grains (1 μm-10 μm). At the same time, the graphene at the grain boundaries of the copper grains forms a specific orientation. Compared with traditional copper-based wires, its mechanical properties are greatly improved.

[0029] (3) The present invention has the advantage of continuous production with a uniform feeding rate and extrusion speed. Combining the preheating of the continuous extrusion die and uniform feeding ensures the continuity and stability of the process, is suitable for large-scale industrial production, and reduces energy consumption and costs. Brief Description of the Drawings

[0030] Figure 1 It is the metallographic diagram of Example 1: the metallographic diagram of the copper-based graphene composite material.

[0031] Figure 2 It is the metallographic diagram of Example 1: the metallographic diagram of the copper-based graphene composite material.

[0032] Figure 3 It is the metallographic diagram of Example 1: the metallographic diagram of the copper-based graphene composite material. Detailed Embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0034] Example 1

[0035] The present invention provides a low-energy consumption continuous preparation method for a copper-based graphene composite material, and the method comprises the following steps:

[0036] (1) Mix 1 kg of 50-mesh copper powder with 4 g of α-naphthol, add them into 0.9 L of absolute ethanol, under mechanical stirring at 200 r / min, ultrasonically treat the mixture for 60 min, use a rotary evaporator to treat the mixture in an oil bath at 130 °C for 30 min to remove ethanol, put the powder into a quartz tube furnace, and carry out graphitization treatment under the atmosphere of hydrogen and argon. The hydrogen flow rate is 30 mL / min, the argon flow rate is 70 mL / min, the temperature is 900 °C, and the growth time is 2 h to obtain copper / graphene composite powder prepared by in-situ growth.

[0037] (2) Ball-mill the copper / graphene composite powder prepared by in-situ growth and 1 kg of 200-mesh pure copper powder by a stirred ball mill. Add petroleum ether during ball milling to prevent excessive agglomeration of graphene. The ball milling time is 1 h, the rotation speed of the ball mill is 500 rpm, and argon with a purity of 99.99% is continuously introduced during ball milling to prevent oxidation of the copper powder to obtain mixed granular materials.

[0038] (3) Preheat a continuous extrusion die in a box-type resistance furnace, the preheating temperature is 400 °C, and the time is 45 min. Assemble the preheated die onto a continuous extruder, uniformly pour the mixed granular materials into the extrusion cavity of the continuous extruder, and the extrusion speed is 6 r / min to obtain a copper-based graphene rod blank with a diameter of 8 mm.

[0039] (4) After all the mixed granular materials are extruded, directly carry out multi-pass continuous extrusion on the rod blank. The extrusion ratio of the second pass is 1:1, and the extrusion ratio of the third pass is 3:1 to obtain a copper-based graphene composite wire with a diameter of 3.5 mm. After extrusion, cool the wire in pure water to room temperature.

[0040] (5) Anneal the copper-based graphene composite wire in an atmosphere annealing furnace. Continuously introduce argon as a protective gas during annealing. The annealing time is 30 min, and the annealing temperature is 800 °C. After annealing, cool the furnace to room temperature.

[0041] (6) Assemble the annealed copper-based graphene composite wire onto a cold drawing machine and carry out one-pass cold drawing. Before each pass of cold drawing, it is necessary to re-coat the surface of the copper-based graphene composite wire with a wire drawing lubricant. The cold drawing ratio of each pass is set at 25% to obtain a copper-based graphene composite wire with a diameter of 2.5 mm.

[0042] (7) Annealing: Put the cold-drawn copper-based graphene composite wire into an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 30 min, and the annealing temperature is 300 °C. After annealing, cool the furnace to room temperature to obtain the copper-based graphene composite wire.

[0043] Example 2

[0044] (1) Take 1 kg of 200-mesh copper powder and mix it with 60 g of carbon precursor α-naphthol, and add them to 0.9 L of ethanol. Stir in a mechanical stirrer (rotation speed 450 r / min) for 20 min, and simultaneously perform ultrasonic treatment for 20 min to form a uniform suspension. Use a rotary evaporator to treat it in an oil bath at 130 °C for 45 min to remove ethanol, and obtain copper / α-naphthol powder uniformly coated with the carbon precursor. Place the powder in a quartz tube furnace, introduce hydrogen and argon (volume ratio 1:3), heat it to 700 °C and hold for 6 h to complete in-situ graphene growth, and obtain copper / graphene composite powder.

[0045] (2) Add 3 kg of 200-mesh pure copper powder to the composite powder, add petroleum ether, place it in a stirred ball mill, and ball mill at a speed of 350 rpm for 3 h, and continuously introduce 99.99% argon for protection throughout the process to obtain a uniformly mixed granular material.

[0046] (3) Preheat the continuous extrusion die in a box-type resistance furnace to 500 °C and hold for 30 min. Uniformly add the mixed granular material into the continuous extrusion die cavity, and set the extrusion speed to 5 r / min to obtain a copper-based graphene rod blank with a diameter of 9 mm.

[0047] (4) Preheat the die and the rod blank to 500 °C and hold for 30 min. Assemble the die to the continuous extruder and perform 4 passes of continuous extrusion on the rod blank, with a compression ratio of 1.5:1 for each pass, and finally obtain a copper-based graphene composite wire with a diameter of 2.75 mm.

[0048] (5) Place the copper-based graphene composite wire in an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 40 min, and the annealing temperature is 600 °C. After annealing, cool it to room temperature in the furnace.

[0049] (6) Cold drawing: Assemble the annealed copper-based graphene composite wire to a cold drawing machine and perform two passes of cold drawing. Before each pass of cold drawing, it is necessary to re-coat the surface of the copper-based graphene composite wire with wire drawing lubricant, and the cold drawing ratio for each pass is set at 15% to obtain a copper-based graphene composite wire with a diameter of 1.75 mm.

[0050] (7) Annealing: Place the cold-drawn copper-based graphene composite wire in an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 15 min, and the annealing temperature is 800 °C. After annealing, cool it to room temperature in the furnace to obtain the copper-based graphene composite wire.

[0051] Example 3

[0052] (1) Take 1 kg of 100-mesh copper powder and mix it with 30 g of the carbon precursor α-naphthol, and add them to 0.9 L of ethanol. Stir in a mechanical stirrer (rotation speed 300 r / min) for 30 min, and simultaneously perform ultrasonic treatment for 40 min to form a uniform suspension. Use a rotary evaporator to treat it in an oil bath at 130 °C for 35 min to remove ethanol, obtaining copper / α-naphthol powder uniformly coated with the carbon precursor. Place the powder in a quartz tube furnace, introduce hydrogen and argon (volume ratio 1:3), heat it to 800 °C and hold for 5 h to complete in-situ growth of graphene, obtaining copper / graphene composite powder.

[0053] (2) Add 3 kg of 200-mesh pure copper powder to the composite powder, add petroleum ether, place it in a stirred ball mill, and ball mill at a rotation speed of 200 rpm for 4 h, and continuously introduce 99.99% argon for protection throughout the process to obtain uniformly mixed granular material.

[0054] (3) Preheat a continuous extrusion die in a box-type resistance furnace to 600 °C and hold for 20 min. Uniformly add the mixed granular material into the cavity of the continuous extruder, and set the extrusion speed to 5 r / min to obtain a copper-based graphene rod blank with a diameter of 12 mm.

[0055] (4) Preheat the die and the rod blank to 500 °C and hold for 30 min. Assemble the die to the continuous extruder and perform 4 passes of continuous extrusion on the rod blank, with a compression ratio of 1.5:1 for each pass, and finally obtain a copper-based graphene composite wire with a diameter of 2.5 mm.

[0056] (5) Place the copper-based graphene composite wire in an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 45 min and the annealing temperature is 300 °C. After annealing is completed, cool the furnace to room temperature.

[0057] (6) Cold drawing: Assemble the annealed copper-based graphene composite wire to a cold drawing machine and perform two passes of cold drawing. Before each pass of cold drawing, it is necessary to re-coat the surface of the copper-based graphene composite wire with wire drawing lubricant. The cold drawing ratio for each pass is set at 15% to obtain a copper-based graphene composite wire with a diameter of 2 mm.

[0058] (7) Annealing: Place the cold-drawn copper-based graphene composite wire in an atmosphere annealing furnace for annealing. Continuously introduce argon as a protective gas during annealing. The annealing time is 20 min and the annealing temperature is 600 °C. After annealing is completed, cool the furnace to room temperature to obtain the copper-based graphene composite wire.

[0059] The above-described embodiments only represent the implementation modes of the present invention, but should not be construed as limiting the scope of the patent of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention.

Claims

1. A preparation process of a copper-based graphene composite wire, characterized in that, The preparation process includes in-situ growth, ball milling, continuous extrusion, multi-pass continuous extrusion, first annealing treatment, cold drawing and second annealing treatment, specifically including the following steps: The first step, in-situ growth: Step 1.1, mixing copper powder and carbon precursor and adding them into a solvent to obtain a uniform suspension, where the carbon precursor is α-naphthol; Step 1.2, performing post-treatment on the suspension to obtain copper / α-naphthol powder; Step 1.3, putting the copper / α-naphthol powder into a quartz tube furnace, and performing graphitization treatment under the atmosphere of hydrogen and argon, with the temperature between 700°C and 900°C and the growth time being 2h - 6h, to obtain the copper / graphene composite powder after in-situ growth; The second step, ball milling: mixing the copper / graphene composite powder after in-situ growth with pure copper powder and then performing ball milling to obtain a mixed granular material with a graphene content of 0.1wt% - 2.5wt%; The third step, continuous extrusion: uniformly pouring the mixed granular material into the extrusion cavity of a continuous extruder to obtain a copper-based graphene rod blank; The fourth step, multi-pass continuous extrusion: using a continuous extrusion die to perform multi-pass continuous extrusion on the copper-based graphene rod blank obtained in the third step to obtain a copper-based graphene composite wire; The fifth step, annealing: under the protection of an inert atmosphere, annealing the copper-based graphene composite wire obtained in the fourth step; The sixth step, cold drawing: assembling the annealed copper-based graphene composite wire onto a cold drawing machine and performing multi-pass cold drawing to obtain a copper-based graphene composite wire; The seventh step, secondary annealing: under the protection of an inert atmosphere, annealing the copper-based graphene composite wire obtained in the sixth step to obtain a copper-based graphene composite wire.

2. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that In the first step: In step 1.1, the solvent is ethanol; the size of the copper powder is 50 mesh - 500 mesh; the mass fraction of the carbon precursor added to the copper powder is 0.4wt% - 6wt%; In step 1.2, the post-treatment is specifically: using a rotary evaporator to treat in an oil bath at 130°C for 30min - 45min to remove the solvent, and uniformly coating the carbon precursor on the surface of the copper granular material to obtain copper / α-naphthol powder.

3. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that, In the second step: the mass ratio of the copper / graphene composite powder to the pure copper powder is 1:1 - 1:3; The ball milling time is 1h - 4h, and the rotation speed of the ball mill is 200rpm - 500rpm; Petroleum ether is added before ball milling to prevent excessive agglomeration of graphene; argon with a purity of 99.99% is continuously introduced during ball milling to prevent oxidation of the copper powder.

4. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that, In the third step, the continuous extruder is preheated before use; the extrusion speed is 4r / min - 6r / min; in the fourth step, the continuous extruder is preheated before use, and the number of extrusion passes is 3 - 10 passes.

5. The preparation process of a copper-based graphene composite wire according to claim 4, characterized in that, In the third step, the preheating temperature is 400°C - 600°C and the time is 20min - 45min; in the fourth step, the preheating temperature is 400°C - 600°C and the time is 20min - 45min.

6. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that, In the fifth step, argon is continuously introduced as a protective gas during annealing, the annealing time is 30min - 45min, and the annealing temperature is 300°C - 800°C.

7. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that, In the sixth step, the surface of the copper-based graphene composite wire needs to be re-coated with wire drawing lubricant before each cold drawing pass. The cold drawing ratio for each pass is set at 15%-25%, and the total cold drawing processing rate is 50%-99%.

8. The preparation process of a copper-based graphene composite wire according to claim 1, characterized in that, In the seventh step, argon gas is continuously introduced as a protective gas during secondary annealing. The annealing time is 15 min - 30 min, and the annealing temperature is 300°C - 800°C.

9. A copper-based graphene composite wire, characterized in that, The copper-based graphene composite wire is prepared by using the preparation process described in any one of claims 1-8, and is composed of a copper-based matrix and graphene. The graphene is uniformly distributed in the copper matrix.

10. A copper-based graphene composite wire according to claim 9, characterized in that, The size of the graphene in the copper matrix is between 10 nm and 20 nm, and the average grain size of the copper is between 1 μm and 10 μm; the tensile strength of the copper-based graphene composite wire is above 550 MPa, and the conductivity is above 105% IACS.

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