A method for preparing copper / carbon nanotube composite wire

Abstract

A method for preparing a copper / carbon nanotube composite wire comprises the following steps: firstly preparing carbon nanotube fibers by suspension catalysis or wet spinning, twisting a plurality of fibers into a thicker carbon nanotube wire, performing surface functionalization treatment, and then loading the wire into an oxygen-free copper tube having an inner diameter matching the inner diameter of the copper / carbon nanotube composite wire to obtain a copper / carbon nanotube composite precursor, performing high-temperature heat treatment on the precursor to make the carbon nanotube wire adhere to the copper layer, and finally preparing a finished copper / carbon nanotube composite wire by rolling, drawing and other processing techniques. The invention takes carbon nanotube fibers as the core, and the prepared lightweight, high-performance composite wire has a wide range of application prospects in the fields of new energy electric vehicles, HKHT and GFJG.

Description

Technical Field

[0001] The invention relates to the field of electrical material manufacturing, and in particular to a method for preparing a copper / carbon nanotube composite wire. Background Art

[0002] Among various metal materials, copper has always been regarded as one of the important pillar materials because of its good ductility, high thermal conductivity and electrical conductivity, as well as excellent mechanical properties. It is widely used in electrical, light industry, machinery manufacturing, construction industry, GF industry and other fields. However, with the advancement of science and technology and industry, the application fields of copper, especially in the fields of WX detection and HKHT, have put forward higher requirements on the comprehensive performance of copper materials, and the development of lightweight and high-performance copper-based composite materials has become an urgent task. Among the various reinforcing materials for preparing copper-based composite materials, carbon nanotubes are an ideal multifunctional nanoscale reinforced composite material. First of all, carbon nanotubes have the advantages of light weight and low density; secondly, carbon nanotubes have extremely high mechanical properties, excellent electrical and thermal conductivity, and unique atomic structure. In addition, carbon nanotubes also have extremely high current carrying capacity, which is higher than copper (10 6 A.cm -2 ) is one thousand times higher. Therefore, it is expected that the composite of copper and carbon nanotubes can produce lightweight, high-performance composite wires.

[0003] At present, the commonly used processes for preparing carbon nanotube-reinforced copper-based composites mainly include powder metallurgy, hot pressing sintering, spraying, in-situ self-generation and electrochemical deposition. However, these methods are usually complicated, and the carbon content in the resulting composite material is very low, making it difficult to achieve a lightweight effect. Although composite fibers directly formed by copper plating on the surface with carbon nanotubes as the core can greatly reduce the density of the composite material, it is difficult to form a long wire with uniform structure and practical use. Therefore, it is urgent to develop new research methods and preparation processes to solve the above problems. Taking carbon nanotube fibers as the core, combined with the process technology of tube installation and plastic processing, provides a new research idea for the preparation of lightweight, high-performance copper / carbon nanotube composite wires. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a copper / carbon nanotube composite wire to solve the problems raised in the above background technology. The present invention can simplify the preparation process of copper / carbon nanotube composite wires, form a copper / carbon nanotube composite precursor by fiber tube loading, and adjust the content of carbon nanotubes to achieve a significant reduction in the density of the composite wire, and obtain a composite wire with high conductivity and high current carrying capacity through plastic processing after high-temperature heat treatment. The above method can effectively improve the problem of non-wetting and weak bonding between copper and carbon nanotubes by functionalizing the fiber surface, and enhance its interface connectivity.

[0005] The method for preparing a lightweight, high-performance copper / carbon nanotube composite wire proposed in the present invention comprises the following steps:

[0006] 1. Combine and twist multiple strands of fibers. Take multiple strands of uniform carbon nanotube fibers and combine and twist them into thicker carbon nanotube wires.

[0007] 2. Surface treatment: Perform surface functionalization treatment on the obtained carbon nanotube wires.

[0008] 3. Fiber tube loading: The re-twisted coarse fiber is loaded into an oxygen-free copper tube with an inner diameter matching that of the copper / carbon nanotube combination precursor.

[0009] 4. High temperature heat treatment: The copper / carbon nanotube composite precursor is subjected to high temperature heat treatment to melt or soften it, so that the copper layer and the carbon nanotube wire can be bonded and combined.

[0010] 5. Rolling and drawing into copper / carbon nanotube composite wires. The heat-treated composite is rolled, and then drawn multiple times to obtain copper / carbon nanotube composite wires.

[0011] The present invention adopts the following technical solution:

[0012] A method for preparing a copper / carbon nanotube composite wire comprises the following steps:

[0013] 1) preparing carbon nanotube fibers by a suspension catalytic method or a wet spinning method, and then twisting a plurality of carbon nanotube fibers together to form a carbon nanotube wire;

[0014] 2) performing surface functionalization treatment on the obtained carbon nanotube wire;

[0015] 3) loading the surface functionalized carbon nanotube wire into an oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor;

[0016] 4) heat-treating the copper / carbon nanotube composite precursor so that the copper layer and the carbon nanotube wire are bonded and combined to obtain a heat-treated copper / carbon nanotube composite;

[0017] 5) The copper / carbon nanotube composite body after heat treatment is rolled and drawn to obtain a finished copper / carbon nanotube composite wire.

[0018] Furthermore, in the step 1), the carbon nanotube fiber has a diameter of 10-100 μm, 2-40 strands are taken and twisted, the diameter of the carbon nanotube wire is 0.05-1 mm, and the length is ≥10 cm.

[0019] Furthermore, in step 2), the surface functionalization treatment includes: anodizing pretreatment and impact metal pretreatment. The impact metal element can be nickel, tungsten, titanium, chromium, etc., and the coating thickness is 0.5-2 μm.

[0020] Furthermore, in step 3), the inner diameter of the oxygen-free copper tube is 0.5-2.5 mm, the wall thickness is 0.1-1 mm, and the length is ≥8 cm.

[0021] Furthermore, in step 3), the oxygen-free copper tube is polished with sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone and ethanol.

[0022] Furthermore, in the step 4), the heat treatment process is under an inert gas and hydrogen atmosphere, the heat treatment temperature is 1080-1090° C., and the insulation time is 1-60 min.

[0023] Furthermore, in the step 5), the composite wire is subjected to multiple cold rolling and drawing processes at a deformation rate of 5%-20% per pass and a rate of 0.2-2 m per minute, and finally a copper / carbon nanotube composite wire with a diameter of 0.1-0.5 mm is obtained.

[0024] The copper / carbon nanotube composite wire prepared by the present invention has the following advantages:

[0025] The method of the present invention has novel design, simple process, simple equipment and is easy to implement. With high-strength, low-density carbon nanotube fibers as the core, the homogenized preparation of lightweight, high-performance composite conductors is achieved through tube loading-high temperature-plastic processing. In addition, the carbon nanotube fibers used are surface functionalized to effectively promote the interface connection between copper and carbon. The preparation method provided by the present invention is suitable for the preparation of new lightweight, high-performance composite conductors, which is conducive to achieving technological breakthroughs in the fields of HKHT, GFJG and new energy electric vehicles, has huge commercial value, and can meet the major needs of national economic and social development for energy conservation, environmental protection, green development and energy science and technology innovation.

[0026] The light-weight, high-performance copper / carbon nanotube composite wire prepared by the method of the present invention has an electrical conductivity of 90%-110% and a current carrying capacity of 1.0×10 5 -1×10 6 Acm -2 , tensile strength is 300-550MPa, density is 7.0-9.0g cm -2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The process flow for preparing the copper / carbon nanotube composite wire of the present invention;

[0028] Figure 2 The structure diagram of the copper / carbon nanotube composite wire of the present invention;

[0029] Figure 3Performance characterization of the copper / carbon nanotube composite wire in Example 3 of the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. However, the following embodiments are limited to explaining the present invention, and the protection scope of the present invention should include the entire contents of the claims, and through the description of the following embodiments, those skilled in the art can fully implement the entire contents of the claims of the present invention.

[0031] Figure 1 The following is the process flow for preparing the copper / carbon nanotube composite wire of the present invention. Figure 1 As shown, the method for preparing a lightweight, high-performance copper / carbon nanotube composite wire proposed in the present invention comprises the following steps:

[0032] 1. Combine and twist multiple strands of fibers. Take multiple strands of uniform carbon nanotube fibers and combine and twist them into thicker carbon nanotube wires.

[0033] 2. Surface treatment: Perform surface functionalization treatment on the obtained carbon nanotube wires.

[0034] 3. Fiber tube loading: Load the functionalized carbon nanotube wire into an oxygen-free copper tube with an inner diameter matching that of the fiber to obtain a copper / carbon nanotube composite precursor.

[0035] 4. High temperature heat treatment: The copper / carbon nanotube composite precursor is subjected to high temperature heat treatment to melt or soften it, so that the copper layer and the carbon nanotube wire can be bonded and combined.

[0036] 5. Rolling and cold drawing to form copper / carbon nanotube composite wires. The heat-treated composite is rolled and then cold-drawn multiple times to obtain copper / carbon nanotube composite wires.

[0037] Figure 2 FIG. 1 is a structural diagram of the copper / carbon nanotube composite wire of the present invention. Figure 2 As shown, the copper / carbon nanotube composite wire comprises a copper tube, electroplated nickel and a carbon nanotube wire. The surface of the carbon nanotube wire has an electroplated nickel layer, and the carbon nanotube wire and the electroplated nickel layer are both placed in the copper tube. The nanotube wire is formed by twisting a plurality of carbon nanotube fibers.

[0038] Example 1

[0039] 1. Prepare carbon nanotube fibers using floating chemical vapor deposition. First, prepare a sleeve-shaped carbon nanotube aerogel, densify it, and twist it to form carbon nanotube fibers. Take 15 strands of carbon nanotube fibers and twist them together to form a thicker carbon nanotube wire. Then, perform nickel impact pretreatment on it. Its main function is to introduce a nickel buffer layer on the fiber surface to enhance the interface bonding between the carbon nanotube and the copper layer. The thickness of the nickel is 0.5μm. The diameter of a single carbon nanotube fiber is about 20μm, and the diameter of the carbon nanotube wire is 0.2mm and the length is 10cm.

[0040] 2. An oxygen-free copper tube with an outer diameter of 2 mm, a wall thickness of 0.7 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The functionalized carbon nanotube wire was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0041] 3. Heat treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1090℃, the holding time is 4min, and the whole process is under an inert gas and hydrogen atmosphere.

[0042] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.2 mm.

[0043] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 95% IACS when measured by the Keithley power supply voltmeter using the volt-ampere method. The maximum current carrying capacity of the composite wire was 1.0×10 6 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 500MPa; the density tested by the drainage method is 7.5g cm -2 .

[0044] Example 2

[0045] 1. Prepare carbon nanotube fibers by wet spinning. Press the purchased carbon nanotube stock solution from the spinneret of wet spinning into a thin stream, place it in a coagulation bath - saturated potassium chloride methanol solution to form carbon nanotube fibers, take 5 strands of carbon nanotube fibers and twist them together to form a thicker carbon nanotube line, and use magnetron sputtering to metallize it. The metal element selected is tungsten, which mainly introduces a tungsten buffer layer on the fiber surface to enhance the interface bonding force between the carbon nanotube and the copper layer. The thickness of the metal tungsten is 2μm. The diameter of a single carbon nanotube fiber is about 40μm, and the diameter of the carbon nanotube line is 0.16mm, and the length is 10cm.

[0046] 2. An oxygen-free copper tube with an outer diameter of 2 mm, a wall thickness of 0.7 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The functionalized carbon nanotube wire was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0047] 3. Heat treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace, so that the copper melts at a temperature close to or above the melting point, and the carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1090℃, the holding time is 4min, and the whole process is under an inert gas and hydrogen atmosphere.

[0048] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.3 mm.

[0049] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 110% IACS using a Keithley power supply voltmeter and the maximum current carrying capacity of the composite wire was 7×10 5 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 300MPa; the density tested by the drainage method is 9.0g cm -2 .

[0050] Example 3

[0051] 1. Prepare carbon nanotube fibers using floating chemical vapor deposition. First, prepare a sleeve-shaped carbon nanotube aerogel, densify it, twist it to form carbon nanotube fibers, take 20 strands of carbon nanotube fibers and twist them together to form a thicker carbon nanotube wire. Then, use magnetron sputtering to pre-treat it with metallization. The metal element selected is titanium. Its main function is to introduce a titanium buffer layer on the fiber surface to enhance the interface bonding between the carbon nanotube and the copper layer. The thickness of titanium is 0.5μm. The diameter of a single carbon nanotube fiber is about 10μm, and the diameter of the carbon nanotube wire is 0.12mm and the length is 10cm.

[0052] 2. An oxygen-free copper tube with an outer diameter of 0.5 mm, a wall thickness of 0.1 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The functionalized carbon nanotube wire was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0053] 3. Heat-treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a copper-carbon nanotube wire combination. The temperature control program of the tubular furnace is 10°C / min, the heat treatment temperature is 1090°C, the holding time is 1min, and the whole process is under an inert gas and hydrogen atmosphere.

[0054] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.1 mm.

[0055] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 101% IACS when measured by the Keithley power supply voltmeter using the volt-ampere method. The maximum current carrying capacity of the composite wire was 5.8×10 5 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 480MPa; the density tested by the drainage method is 8.95g cm -2 .

[0056] The performance characteristics of composite conductors are as follows: Figure 3 As shown, Figure 3 (a) is the tensile strength of the composite wire prepared under this condition. It can be seen from the figure that the tensile strength of the composite wire can reach 480MPa. The tensile strength of pure copper processed under similar conditions is generally less than 400MPa. Figure 3 (b) is the density and specific conductivity of the composite wire and pure copper prepared under this condition, Figure 3(b) It can be seen that under the same diameter, the density of the composite conductor is lower, which is 2.5% lighter than pure copper. At the same time, the measured conductivity of the composite conductor is maintained at a relatively high value (101% IACS), that is, under the condition of weight reduction, the conductivity increases, which is an ultra-high level that has not been achieved in current domestic and foreign research. Therefore, the specific conductivity is also greatly improved, which is 3.5% higher than pure copper. Figure 3 (c) is the current carrying capacity of the composite conductor and pure copper prepared under this condition. It can be clearly seen from the figure that the current carrying capacity of the composite conductor is nearly twice that of pure copper, which is at the leading level among copper-based composite materials.

[0057] Example 4

[0058] 1. Carbon nanotube fibers were prepared by floating chemical vapor deposition. First, a sleeve-shaped carbon nanotube aerogel was prepared. After densification and twisting, carbon nanotube fibers were formed. Ten strands of carbon nanotube fibers were taken and twisted together to form a thicker carbon nanotube wire. Subsequently, the metalization was pre-treated by magnetron sputtering. The metal element selected was chromium. Its main function was to introduce a chromium buffer layer on the fiber surface to enhance the interface bonding between the carbon nanotube and the copper layer. The thickness of the metal chromium was 0.5μm. The diameter of a single carbon nanotube fiber was about 20μm, and the diameter of the carbon nanotube wire was 0.12mm and the length was 10cm.

[0059] 2. An oxygen-free copper tube with an outer diameter of 0.8 mm, a wall thickness of 0.3 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The functionalized carbon nanotube wire was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0060] 3. Heat-treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1080℃, the holding time is 60min, and the whole process is under an inert gas and hydrogen atmosphere.

[0061] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.5 mm.

[0062] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 98% IACS using a Keithley power supply voltmeter and the maximum current carrying capacity of the composite wire was 8×10 5 Acm-2 ; The strength of the composite conductor tested by a tensile machine is 400MPa; the density tested by the drainage method is 8.5g cm -2 .

[0063] Example 5

[0064] 1. Carbon nanotube fibers were prepared by floating chemical vapor deposition. First, a sleeve-shaped carbon nanotube aerogel was prepared. After densification and twisting, carbon nanotube fibers were formed. Ten strands of carbon nanotube fibers were taken and twisted to form a thicker carbon nanotube line. The surface was pre-oxidized and the carbon nanotube line was placed in an O2 Plasma device for 2 minutes to make the surface contain oxidized functional groups and enhance the interface bonding between the carbon nanotube and the copper layer. The diameter of a single carbon nanotube fiber is about 40μm, the diameter of the carbon nanotube line is 0.3mm, and the length is 10cm.

[0065] 2. An oxygen-free copper tube with an outer diameter of 2.5 mm, a wall thickness of 1.0 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The carbon nanotube wire after oxidation pretreatment was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0066] 3. Heat treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1090℃, the holding time is 4min, and the whole process is under an inert gas and hydrogen atmosphere.

[0067] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.5 mm.

[0068] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 90% IACS when measured by the Keithley power supply voltmeter using the volt-ampere method. The maximum current carrying capacity of the composite wire was 7.5×10 5 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 500MPa; the density tested by the drainage method is 7.0g cm -2 .

[0069] Example 6

[0070] 1. Carbon nanotube fibers were prepared by floating chemical vapor deposition. First, a sleeve-shaped carbon nanotube aerogel was prepared. After densification and twisting, carbon nanotube fibers were formed. 40 strands of carbon nanotube fibers were taken and twisted to form a thicker carbon nanotube line. The impact metal nickel pretreatment was performed. The main function of the pretreatment was to introduce a nickel buffer layer on the fiber surface to enhance the interface bonding force between the carbon nanotube and the copper layer. The thickness of the metal nickel was 0.5 μm. The diameter of a single carbon nanotube fiber was about 10 μm, and the diameter of the carbon nanotube line was 0.3 mm and the length was 10 cm.

[0071] 2. An oxygen-free copper tube with an outer diameter of 2.0 mm, a wall thickness of 0.5 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. The functionalized carbon nanotube wire was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0072] 3. Heat treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1090℃, the holding time is 2min, and the whole process is under an inert gas and hydrogen atmosphere.

[0073] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon nanotube composite wire with a diameter of 0.5 mm.

[0074] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 93% IACS when measured by the Keithley power supply voltmeter using the volt-ampere method. The maximum current carrying capacity of the composite wire was 1.0×10 5 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 350MPa; the density tested by the drainage method is 8.0g cm -2 .

[0075] Example 7

[0076] 1. Carbon nanotube fibers were prepared by floating chemical vapor deposition. First, a sleeve-shaped carbon nanotube aerogel was prepared. After densification and twisting, carbon nanotube fibers were formed. Two strands of carbon nanotube fibers were twisted together to form a thicker carbon nanotube line. The carbon nanotube line was pretreated by impact with metal nickel. The thickness of the metal nickel was 1 μm. The diameter of a single carbon nanotube fiber was about 100 μm, and the diameter of the carbon nanotube line was 0.15 mm and the length was 10 cm.

[0077] 2. An oxygen-free copper tube with an outer diameter of 2.0 mm, a wall thickness of 0.7 mm, and a length of 9 cm was selected. The oxygen-free copper tube was polished with fine sandpaper and ultrasonically cleaned in the order of ethanol, acetone, 5 wt% hydrochloric acid, acetone, and ethanol. A single carbon fiber was loaded into the oxygen-free copper tube to obtain a copper / carbon nanotube composite precursor.

[0078] 3. Heat treat the copper / carbon nanotube composite precursor in a chemical vapor deposition furnace. The copper layer melts at a temperature close to or above the melting point. The carbon nanotube wire supports the copper layer so that it is tightly wrapped on the surface of the carbon nanotube wire to form a combination of copper and carbon nanotube wire. The temperature control program of the tubular furnace is 10℃ / min, the heat treatment temperature is 1090℃, the holding time is 4min, and the whole process is under an inert gas and hydrogen atmosphere.

[0079] 4. The heat-treated copper / carbon nanotube composite is rolled into a round rod, and multiple drawing processes are performed at a deformation rate of 20% per pass and a speed of 2 m per minute to finally obtain a copper / carbon fiber composite wire with a diameter of 0.4 mm.

[0080] The mechanical and electrical properties of the composite wire were tested. The conductivity of the composite wire was 95% IACS using a Keithley power supply voltmeter and the maximum current carrying capacity of the composite wire was 3×10 5 Acm -2 ; The strength of the composite conductor tested by a tensile machine is 440MPa; the density tested by the drainage method is 8.0g cm -2 .

[0081] The present invention does not elaborate on some of the common technologies of those skilled in the art. The above-described embodiments are only descriptions of preferred implementations of the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementations described. Without departing from the design spirit of the present invention, various modifications and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A method for preparing a copper / carbon nanotube composite wire, characterized in that: The steps include: 1) Twisting 2-40 strands of carbon nanotube fibers together to form a carbon nanotube wire with a diameter of 0.05-1 mm, wherein the diameter of a single carbon nanotube fiber is 10-100 µm; 2) performing surface functionalization treatment on the carbon nanotube wire, including anodizing pretreatment and magnetron sputtering metallization pretreatment, wherein the thickness of the metallization layer is 0.5-2µm, and the metal element is selected from any one of nickel, tungsten, titanium or chromium; 3) placing the treated carbon nanotube wire into an oxygen-free copper tube with a matching inner diameter, wherein the oxygen-free copper tube has an outer diameter of 0.5-2.5 mm and a wall thickness of 0.1-1 mm; 4) Under an inert gas and hydrogen atmosphere, heat-treating the copper / carbon nanotube composite precursor at 1080-1090°C for 1-60 minutes to bond the copper layer to the carbon nanotube wire; 5) The composite body is subjected to multiple cold rolling and drawing at a deformation rate of 5%-30% per pass and a rate of 0.2-2 m per minute to obtain a composite wire with a diameter of 0.1-0.5 mm.

2. The preparation method according to claim 1, characterized in that: The carbon nanotube fibers are prepared by a suspension catalytic method or a wet spinning method, and the length of the carbon nanotube line after twisting is ≥10cm.

3. The preparation method according to claim 1, characterized in that: The composite wire has a density of 7.0-9.0 g / cm³, a tensile strength of 300-550 MPa, an electrical conductivity of 90%-110% IACS, and a current carrying capacity of 1.0×10 5 -1×10 6 A cm -2 .

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