Preparation method of high-performance conductive metal-based composite material and cable

Abstract

The invention provides a preparation method of a high-performance conductive metal-based composite material and a cable, and relates to the technical field of composite material preparation. Comprising the following steps: S1, depositing a plurality of layers of graphene on the surface of a high-purity oxygen-free metal wire by using a CVD (Chemical Vapor Deposition) process and carbon source gas and hydrogen as precursors, and then weaving the metal wire with the graphene deposited on the surface into a graphene metal net; or depositing a plurality of layers of graphene on the surface of the woven high-purity oxygen-free metal net; s2, stacking the plurality of layers of metal nets after graphene deposition, and performing hot pressing or hot rolling or hot drawing on the metal nets to obtain a flaky graphene metal composite material; and S3, the outer surface of the conductive metal alloy is wrapped with the flaky graphene metal composite material, and then cold rolling or cold drawing or hot pressing or hot rolling or hot drawing is conducted on the conductive metal alloy, so that the conductive metal-based composite material of the core-shell structure is obtained. The conductive metal-based composite material with high hydrophobicity, low friction coefficient and long service life and the cable can be prepared by the method.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and in particular to a method for preparing a highly hydrophobic, low friction coefficient, and long-life conductive metal-based composite material, as well as a cable made of the conductive metal-based composite material. Background Art

[0002] The contact wires of high-speed railways are made of high-strength copper alloys such as copper-silver, copper-tin, copper-magnesium, and copper-chromium-zirconium alloys, which have good electrical conductivity and strength. However, in extreme weather conditions such as low temperature, rain and snow, the surface of the copper wire is prone to ice and loss of conductivity, resulting in the failure of high-speed rail to operate, causing huge losses to the national economy. Therefore, graphene composites are currently commonly used as contact wires. Graphene is a new type of carbon material composed of carbon atoms in a two-dimensional honeycomb structure with sp2 hybrid orbits. The thickness of a single layer of graphene is only 0.34nm. It has the characteristics of high specific surface area, good electrical conductivity, thermal conductivity, and excellent mechanical properties. In addition, the super chemical inertness of graphene makes it have better corrosion resistance and thermal stability than ordinary surface coatings, and can stably withstand high temperatures above 1500 degrees Celsius. The surface of pure graphene will acquire special functions such as hydrophobicity, ice repellency, corrosion resistance, thermal conductivity, and electrical conductivity.

[0003] The graphene grown in situ by the CVD method is tightly bonded to the substrate and has strong hydrophobicity. At the same time, graphene has good lubrication properties. Graphene is grown in situ on the surface of copper wires by the CVD method. The hydrophobicity of graphene can make it more difficult for the surface of copper alloy wires to freeze, while not affecting the friction properties of the wires. Currently, there are patents for growing graphene on the surface of pure copper foil by CVD, and then hot isostatic pressing, vacuum hot extrusion and other operations on the graphene-coated copper foil roll / laminate to form a block, such as 202310981698.9 Graphene / copper composite material preparation device and method based on CVD and hot pressing, etc., or graphene is grown in situ on the surface of pure copper powder by the CVD method, and the graphene-coated copper powder is formed into a block by vacuum hot pressing or vacuum sintering, and finally the graphene-copper composite block is cold drawn or cold rolled to make a graphene composite copper wire. The composite material prepared by this method has good mechanical properties, but only the side of the graphene is exposed, and the exposed graphene appears in the form of dots and lines (such as Figure 2 As shown in the figure, for example, a method for preparing a high-conductivity graphene / copper composite wire with patent application number 202311100229.8. However, there are still some problems in these schemes. For example, the exposure ratio of graphene on the surface of the graphene copper foil composite material is too small, and the hydrophobic and lubricating properties of the two-dimensional surface of graphene cannot be fully utilized; in addition, there is no metallurgical bonding between graphene and copper, the interface bonding force is weak, and the strength of the copper wire of the graphene composite material prepared by copper powder is less than that of copper alloy. Summary of the invention

[0004] The present invention discloses a preparation method of a high-performance conductive metal matrix composite material, aiming to improve the problems of insufficient hydrophobicity and lubricity of cables made of existing composite materials.

[0005] The present invention adopts the following scheme:

[0006] The present application provides a preparation method of a high-performance conductive metal matrix composite material, comprising the following steps:

[0007] S1. Using the CVD process, taking a carbon source gas and hydrogen as precursors, depositing several layers of graphene on the surface of a high-purity oxygen-free conductive metal wire, and then weaving the metal wire with graphene deposited on its surface into a graphene metal mesh; or depositing several layers of graphene on the surface of a pre-woven high-purity oxygen-free metal mesh;

[0008] S2. Stacking several layers of the deposited conductive metal meshes and performing hot pressing or hot rolling or hot drawing on them to obtain a sheet-like graphene conductive metal composite material;

[0009] S3. Wrapping the sheet-like graphene conductive metal composite material on the outer surface of a conductive metal alloy, and then performing cold rolling or cold drawing or hot pressing or hot rolling or hot drawing on it to obtain a conductive metal matrix composite material with a core-shell structure.

[0010] Further, in S1, the deposition temperature is 200°C - 1100°C.

[0011] Further, in S1, the diameter of the high-purity oxygen-free conductive metal wire used is 100 nm - 1 mm.

[0012] Further, in S1, 3 - 10 layers of graphene are deposited on the surface of the conductive metal mesh.

[0013] Further, in S2, the number of stacked conductive metal mesh layers is 5 - 10000 layers.

[0014] Further, in S2, when performing hot rolling or hot drawing, it is carried out under vacuum conditions or under the protection of an inert gas, and the temperature of hot rolling or hot drawing is 500°C - 1100°C.

[0015] The present invention also provides a cable made of a high-performance conductive metal matrix composite material, and the cable is made of a conductive metal matrix composite material prepared by the preparation method of the high-performance conductive metal matrix composite material described in any one of the above.

[0016] Beneficial effects:

[0017] The shell layer of the cable prepared by the preparation method of the present invention is a conductive metal matrix composite material with uniformly distributed two-dimensional graphene. During the wear process, the continuously exposed two-dimensional surface of the uniformly distributed graphene ensures the lubricity and hydrophobic properties of the composite material surface under long-term operation. At the same time, the continuous pure conductive metal matrix in the cable shell layer ensures the toughness of the cable shell layer. The conductive metal alloy in the cable core ensures the strength of the conductive wire mesh. By controlling the number of conductive metal mesh layers set during vacuum hot pressing, the thickness of the graphene conductive metal matrix composite material can be adjusted, thereby obtaining a cable shell layer of a conductive metal matrix composite material with a long service life, low friction coefficient, and high hydrophobicity. Brief Description of the Drawings

[0018] Figure 1 It is a schematic diagram of the preparation of a composite material formed by a conductive metal mesh coated with graphene in an embodiment of the present invention.

[0019] Figure 2 It is a metallographic photo of a conductive metal matrix graphene composite material made by other technical solutions.

[0020] Figure 3 It is a photo of a copper cable of a hot-pressed graphene copper mesh made in Example 3.

[0021] Figure 4 It is the Raman spectrum of Example 2 and Example 3.

[0022] Figure 5 It is a schematic diagram of the contact angle test result of Example 2.

[0023] Figure 6 It is a schematic diagram of the contact angle test result of Example 3.

[0024] Figure 7 It is a schematic diagram of the contact resistance test results of Example 2 and Example 3.

[0025] Figure 8 It is a schematic diagram comparing the wear test results of Example 3 and a pure copper cable. Detailed Embodiments

[0026] Example 1

[0027] Combined with Figure 1 , this embodiment provides a preparation method of a high-performance conductive metal matrix composite material, including the following steps:

[0028] S1. Using the CVD process, taking a carbon source gas and hydrogen as precursors, deposit several layers of graphene on the surface of a conductive metal mesh woven from high-purity oxygen-free conductive metal wires;

[0029] S2. Stack the deposited conductive metal meshes in several layers, and perform hot pressing, hot rolling, or hot drawing on them to obtain a flaky graphene conductive metal composite material;

[0030] S3. Wrap the flaky graphene conductive metal composite material around the outer surface of the conductive metal alloy, and then perform cold rolling, cold drawing, hot pressing, hot rolling, or hot drawing on it to obtain a conductive metal matrix composite material with a core-shell structure.

[0031] In this embodiment, the conductive metal wire can be a copper wire, a silver wire, or other conductive metal materials, which are used for conducting electricity and providing a certain strength. For the convenience of description, in this embodiment, the conductive metal wire is taken as an example of a copper wire for illustration.

[0032] In this embodiment, the CVD process is an existing process, and its process will not be elaborated here. In S1, the deposition temperature is 200°C - 1100°C, preferably around 800°C, and the deposition effect is good. The diameter of the high-purity oxygen-free conductive metal wire used is 10μm - 1mm, so that it can meet the requirements of conductivity and strength, and can produce a cable structure with a smaller volume. Deposit 3 - 10 layers of graphene on the surface of the conductive metal mesh, preferably deposit 5 - 6 layers of graphene, so that it has a better exposure effect and ensures the lubricity and hydrophobic properties of the composite material surface under long-term operation. The carbon source gas can be one or more of methane, ethane, ethylene, and acetylene, including but not limited to this.

[0033] In step S2, the number of stacked conductive metal mesh layers is 5 - 10000 layers. The continuous stacking of the pure conductive metal matrix ensures the toughness of the cable shell layer, and preferably 200 - 500 layers are used. After stacking, hot rolling or hot drawing is performed. Here, when hot rolling or hot drawing is carried out, it is carried out under vacuum conditions or under the protection of an inert gas. The temperature of hot rolling or hot drawing is 500°C - 1100°C. The inert gas can be argon, nitrogen, etc.

[0034] In step S3, wrap the flaky graphene conductive metal matrix composite material around the surface of the conductive metal alloy to form a wrapped core structure, and then use the method of cold rolling or cold drawing to enable the flaky graphene conductive metal matrix composite material to achieve metallurgical bonding with the conductive metal alloy, and the interfacial bonding force is strong, so as to further obtain a conductive metal matrix composite material with a core-shell structure. In another embodiment, it is also possible to use the method of hot pressing, hot rolling, or hot drawing under vacuum (or a protective inert atmosphere) to obtain a conductive metal matrix composite material with a core-shell structure. The temperature of hot pressing, hot rolling, or hot drawing is 500°C - 1100°C. The conductive metal alloy in this embodiment can be applied to the catenary wire suitable for high-speed trains.

[0035] In the embodiment of the present invention, a high-purity oxygen-free conductive metal wire is first woven, and then graphene is deposited on the conductive metal mesh by the CVD method. The conductive metal meshes coated with multiple layers of graphene are overlapped and hot-rolled under vacuum or inert gas protection to form a sheet-like composite material of conductive metal / graphene. Finally, this material is used for the surface coating of conductive metal wires, which is applicable to the catenary wires of high-speed trains, increasing the surface hydrophobicity of the catenary wires, maintaining good electrical conductivity, low friction coefficient, and long service life.

[0036] Example 2

[0037] Wind 3 layers of graphene copper mesh around the smooth surface of the copper cable, then wind 1 layer of graphite cloth, fix it with 1 layer of graphite felt, and then fix and extrude it with a clamp. After vacuum sealing, heat-treat it in a muffle furnace and keep it at 1000 °C for 30 min to form a high-performance composite material copper cable.

[0038] Example 3

[0039] Wind 5 layers of graphene copper mesh around the smooth surface of the copper cable, then wind 1 layer of graphite cloth, fix it with 1 layer of graphite felt, and then fix and extrude it with a clamp. After vacuum sealing, heat-treat it in a muffle furnace and keep it at 1000 °C for 30 min to form a high-performance composite material copper cable (such as Figure 3 ).

[0040] Perform Raman spectrum tests on the high-performance composite material copper cables obtained in Example 2 and Example 3, and obtain the Raman spectrum Figure 4 using a Raman spectrometer of Thermo Fisher DXR2xi, which shows the Raman spectrum of the surface of the copper cable after vacuum hot-pressing graphene copper mesh. The spectra all have characteristic peaks of graphene, but the characteristic peaks of graphene shown by the composite material copper cable loaded with 5 layers of graphene copper mesh are stronger and the spectra are more standard. It shows that the more the number of layers of graphene copper mesh hot-pressed on the surface of the copper cable, the greater the content of graphene on the surface of the composite material.

[0041] Perform contact angle tests on the high-performance composite material copper cables obtained in Example 2 and Example 3, and test them using an optical contact angle measuring instrument of OCA15EC. The average surface contact angle of the composite material copper cable loaded with 3 layers of graphene copper mesh is 129.6° ( Figure 5 ), and the average surface contact angle of the composite material copper cable loaded with 5 layers of graphene copper mesh is 133.5° ( Figure 6 ). The larger the angle of the average contact angle, the better the surface hydrophobicity. It can be clearly seen that the average contact angle of the composite material copper cable loaded with 5 layers of graphene copper mesh is greater than that of the composite material copper cable loaded with 3 layers of graphene copper mesh, indicating that increasing the number of layers of graphene copper mesh is beneficial to improving the hydrophobicity of the surface of the copper cable.

[0042] The contact resistance of the high-performance composite copper cables obtained in Example 2 and Example 3 was tested. The test results were obtained using a ST2921B proton exchange fuel cell bipolar plate and a carbon paper resistance tester. Figure 7 As shown in the test result graph, when the vertical pressure on the side wall of the copper cable is relatively small (between 0.5 - 3 MPa), the composite copper cable loaded with 5 layers of graphene copper mesh has a smaller contact resistance than the pure copper cable. This shows that loading 5 layers of graphene copper mesh not only does not affect the electrical conductivity of the copper cable, but instead increases the electrical conductivity of the copper cable to a certain extent.

[0043] The surface wear test was carried out on the composite copper cable loaded with 5 layers of graphene copper mesh and the pure copper cable obtained in Example 3. The test was carried out using a wear test device of model MFT - 5000 (test parameters: duration: 5 min; rotation speed: 200 rpm, pressure: 5 N; sandpaper: 2000M). According to Figure 8 the test results shown, the surface friction coefficient of the composite copper cable loaded with 5 layers of graphene copper mesh is 0.179, while the surface friction coefficient of the pure copper cable is 0.241. It can be seen that the composite copper cable loaded with 5 layers of graphene copper mesh has better surface wear resistance than the pure copper cable.

[0044] It should be understood that the above are only the preferred embodiments of the present invention. The protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention.

[0045] The introduction of the drawings used in the above embodiments only shows some embodiments of the present invention and should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

Claims

1. A preparation method of a high-performance conductive metal matrix composite material, characterized in that, It includes the following steps: S1. Using the CVD process, taking carbon source gas and hydrogen as precursors, depositing several layers of graphene on the surface of a high-purity oxygen-free conductive metal wire, and then weaving the metal wire with graphene deposited on its surface into a graphene metal mesh; or depositing several layers of graphene on the surface of a pre-woven high-purity oxygen-free metal mesh; S2. Stacking several layers of the deposited conductive metal meshes and performing hot pressing or hot rolling or hot drawing on them to obtain a sheet-like graphene conductive metal composite material; S3. Wrapping the sheet-like graphene conductive metal composite material on the outer surface of a conductive metal alloy, and then performing cold rolling or cold drawing or hot pressing or hot rolling or hot drawing on it to obtain a core-shell structured conductive metal matrix composite material.

2. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, characterized in that, In S1, the deposition temperature is 200°C - 1100°C.

3. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, wherein In S1, the diameter of the used high-purity oxygen-free conductive metal wire is 100 nm - 1 mm.

4. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, characterized in that In S1, 3 - 10 layers of graphene are deposited on the surface of the conductive metal mesh.

5. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, wherein, In S2, the number of stacked conductive metal mesh layers is 5 - 10000 layers.

6. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, wherein, In S2, when performing hot rolling or hot drawing, it is carried out under vacuum conditions or under the protection of an inert gas, and the temperature of hot rolling or hot drawing is 500°C - 1100°C.

7. The preparation method of the high-performance conductive metal matrix composite material according to claim 1, wherein, In S3, when performing hot pressing or hot rolling or hot drawing to obtain a core-shell structured conductive metal matrix composite material, the temperature of hot pressing or hot rolling or hot drawing is 500°C - 1100°C.

8. A cable made of a high-performance conductive metal matrix composite, characterized in that, The cable is made of a conductive metal matrix composite material prepared by the preparation method of the high-performance conductive metal matrix composite material according to any one of claims 1 - 8.

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