A preparation method of nitrogen-doped graphene / copper wire high current-carrying composite material

Abstract

The invention discloses a preparation method of a nitrogen-doped graphene / copper wire high current-carrying composite material, comprising the following steps: (1) placing a copper wire of a certain diameter in a microwave tube furnace, and introducing hydrogen for annealing; (2) using electron beam evaporation to plate a nano-metal nickel film on the annealed copper wire obtained in step (1); (3) using a device as shown in the following figure to apply a silk fibroin organic carbon source on the surface of the obtained copper-nickel material, and drying it; (4) placing the dried sample in step (3) in a microwave tube furnace, opening the vacuum, introducing nitrogen for plasma heat treatment, so that the silk fibroin is converted into nitrogen-doped graphene and coated on the surface of the copper wire, and a nitrogen-doped graphene composite copper wire high current-carrying composite material is obtained. The invention solves the problem that it is difficult to evenly apply a silk fibroin solution on a small-sized filamentous material, and ensures that the nitrogen-doped graphene converted from the silk fibroin can evenly coat the entire copper wire, so that the current-carrying capacity of the copper wire is improved.

Description

Technical Field

[0001] The invention relates to the technical field of high current-carrying composite materials, and in particular to a method for preparing a nitrogen-doped graphene / copper wire high current-carrying composite material. Background Art

[0002] In recent years, the development of electronic devices has been undergoing a paradigm shift as they continue to miniaturize. Miniaturization has enabled electronic devices to be more portable and versatile. At the same time, the functionality and performance of these devices have increased. While the miniaturization of transistor memory devices has kept pace with practical needs, progress has been slow in the development of conductors (such as copper and gold) that power components within the devices. As device size decreases, this leads to higher current densities, reaching the limits of today's devices with conventional conductors (such as Cu and Au). In fact, the current density devices in these devices have long exceeded the breakdown limits of Cu and Au. Therefore, new conductors with higher current carrying capacity are in great demand.

[0003] Many emerging technology fields have increasingly higher requirements for copper materials, especially high-current-carrying copper materials. One of the methods to achieve high-strength and high-current-carrying copper-based materials is to combine graphene with ultra-high mechanical and electrical properties with copper to prepare composite materials.

[0004] Graphene has ultra-high carrier mobility and a maximum current carrying capacity far exceeding that of copper. Copper and its alloys have excellent thermal conductivity, electrical conductivity, corrosion resistance and other properties, making them important industrial metals. On this basis, new composite materials are formed with graphene as a reinforcement, which greatly improves the mechanical properties, wear resistance, thermal conductivity, electrical conductivity, corrosion resistance and other aspects. Therefore, graphene can be compounded with a copper matrix to obtain a composite material to improve the current carrying capacity of the copper matrix.

[0005] The key and difficulty of preparing high current-carrying graphene / copper wire composite conductors lies in the interface bonding problem between copper and graphene. The wettability of copper wire is poor, so it is difficult to coat copper and silk protein solution together in the actual experimental process, so it is necessary to plate a layer of metal on the copper surface to form a good interface to improve the current carrying capacity of the graphene copper wire composite conductor. The present invention uses electron beam evaporation to plate a layer of nickel film on the surface of the copper wire, thereby improving the wettability of the copper wire; the motor is used to spin-coat the silk protein solution on the micron-sized copper wire, which solves the problem that the silk solution is difficult to apply evenly on small-sized filamentous materials, and the operation is safe, simple, and low-cost, ensuring that the nitrogen-doped graphene converted from silk can evenly coat the entire copper wire, so that the current carrying capacity of the copper wire is improved. Summary of the invention

[0006] The present invention aims to solve the above-mentioned problems existing in the prior art graphene copper wire composite technology, solves the problem that the silk solution is difficult to be evenly applied on small-sized filamentary materials, and has safe and simple operation and low cost, and ensures that the nitrogen-doped graphene converted from silk can evenly cover the entire copper wire, thereby improving the current carrying capacity of the graphene / copper wire composite material.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a nitrogen-doped graphene / copper wire high current-carrying composite material comprises the following steps:

[0009] (1) Place a copper wire of a certain diameter into a microwave tube furnace, open the vacuum, and introduce hydrogen for annealing;

[0010] (2) coating the annealed copper wire obtained in step (1) with a nano-metal nickel film by electron beam evaporation;

[0011] (3) Coating the surface of the copper-nickel wire material obtained in step (2) with a silk fibroin solution and drying it; the specific steps are as follows: align two motors with the same power and the same speed at the same height; fix a thick copper wire (with a diameter of 500-1000 μm) between the two motors for connection so that the two motors can rotate at the same speed; then solder the sample copper wire to the two motors with tin wire; use a rubber-tipped dropper to evenly apply the silk fibroin solution on the surface of the sample copper wire; power on the motor to enable the copper wire coated with silk fibroin to rotate with the motor; turn off the power, remove the sample, and dry it under an infrared baking lamp.

[0012] (4) placing the sample obtained in step (3) into a microwave tube furnace, opening the vacuum, introducing nitrogen gas for plasma heat treatment, so that the silk fibroin is converted into nitrogen-doped graphene and coated on the surface of the copper wire, and finally obtaining a graphene / copper wire composite material.

[0013] Preferably, in step (1), the diameter of the copper wire is greater than 20 microns, the hydrogen flow rate is controlled at 50 sccm during annealing of the copper wire, the gas pressure is adjusted to 200-300 Pa, the microwave power is first adjusted to 1000 W, preheated for 10 minutes, and then adjusted to 1500 W, and the reaction time is 15 minutes.

[0014] Preferably, in step (2), when the nano-metal nickel film is plated by electron beam evaporation, the electron beam current is 150 mA, the plating time is 3 min, and the nickel film thickness is between 5-20 nm.

[0015] Preferably, in step (3), the motor speed is 17000 r / h, the motor power supply time is 60 s, and the baking time under the infrared baking lamp is 1 h.

[0016] Preferably, in step (4), the nitrogen flow rate is controlled at 50 sccm, the gas pressure is adjusted to 2000-300 Pa, the microwave power is 2000 W, and the reaction time is 25 min. Microwave power has a great influence on graphene growth. The higher the power, the better the crystallinity of graphene. However, too high power will produce sp3 hybrid defects.

[0017] Therefore, the present invention has the following beneficial effects: using silk fibroin as a carbon source and adopting microwave heating technology to composite nitrogen-doped graphene and surface-modified copper wire, compared with the traditional method, the process is simple in steps and fast in method; compared with the traditional graphene composite copper wire material, the nitrogen-doped graphene can be evenly distributed and coated on the surface of the copper wire, and the current carrying capacity is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The SEM and energy spectrum of the copper wire surface after the electron beam nickel film is plated in Example 1. A layer of nickel film is deposited on the reaction copper wire to improve the wettability between graphene and the copper wire.

[0019] Figure 2 The macroscopic morphology, surface SEM, cross-sectional SEM, and Raman spectra of the nitrogen-doped graphene composite surface nickel film copper wire in Example 1 reflect that the nitrogen-doped graphene is evenly coated on the surface of the copper wire, a good interface is formed between the graphene and the copper wire, and the graphene has good crystallinity.

[0020] Figure 3 This is a VI relationship diagram of the current carrying test of the nitrogen-doped graphene composite copper wire material in Example 1 and the comparison pure copper wire.

[0021] Figure 4 It is a numerical diagram of current carrying values ​​measured multiple times for the nitrogen-doped graphene composite copper wire material in Example 1 and the pure copper wire for comparison.

[0022] Figure 5 It is a schematic diagram of the principle of the preparation method of the nitrogen-doped graphene / copper wire high current-carrying composite material of the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] Embodiment 1:

[0025] (1) Figure 5 As shown, a copper wire with a diameter of 50 microns is placed in a microwave tube furnace, the vacuum is turned on, hydrogen is introduced, the hydrogen flow rate is controlled at 50 sccm, the gas pressure is adjusted to 200-300 Pa, the microwave power is first adjusted to 1000 W, preheated for 10 minutes, and then adjusted to 1500 W, and the reaction time is 15 minutes.

[0026] (2) The annealed copper wire obtained in step (1) is placed in an electron beam evaporation coating device, a nickel target is placed, the electron beam current is adjusted to 150 mA, the coating time is 3 minutes, and the nickel film thickness is between 5-20 nm.

[0027] (3) Two motors with the same power and a rotation speed of 17,000 r / h were placed on foams of equal height and aligned, and the two motors were welded together using a thick copper wire with a diameter of 500 μm.

[0028] (4) Weld the nickel-plated copper wire to the two motors.

[0029] (5) Use a rubber-tipped dropper to evenly apply the silk solution on the surface of the sample copper wire, power it with a No. 5 battery, spin coat for 60 seconds, then disconnect to stop powering, and remove the battery.

[0030] (6) Bake the sample in (5) under an infrared baking lamp for 1 h.

[0031] (7) The sample after step (6) was placed in a plasma microwave and treated at high temperature and high pressure for 25 min in a nitrogen atmosphere (flow rate controlled at 50 sccm), wherein the microwave power was 2000 W.

[0032] (10) The current carrying capacity is measured by 2651A digital source meter.

[0033] (2) After treatment, its SEM image and energy spectrum are as follows Figure 1 As shown; (9) After treatment, the sample is cooled and taken out to obtain a graphene composite copper wire high current carrying material, the macroscopic morphology, surface SEM image, cross-sectional SEM image, graphene Raman spectrum, current carrying test V_I relationship curve and multiple current carrying value graphs are shown respectively. Figure 2 , Figure 3 , Figure 4 shown.

[0034] from Figure 1 It can be seen that a layer of nickel film is deposited on the copper wire to improve the wettability between graphene and the copper wire.

[0035] from Figure 2 It can be seen that nitrogen-doped graphene is evenly coated on the surface of the copper wire, a good interface is formed between the graphene and the copper wire, and the graphene has good crystallinity.

[0036] from Figure 3 , Figure 4 It can be seen that under the same size and the same processing conditions, the maximum current carrying capacity of the graphene composite copper wire material is greatly improved compared with the annealed pure copper wire.

[0037] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for preparing a nitrogen-doped graphene / copper wire high current-carrying composite material, characterized in that: The following steps are involved: (1) Place a copper wire of a certain diameter into a microwave tube furnace, open the vacuum, and introduce hydrogen for annealing; (2) coating the annealed copper wire obtained in step (1) with a nano-metal nickel film by electron beam evaporation; (3) Coating the surface of the copper-nickel wire material obtained in step (2) with a silk fibroin solution and drying it; the specific steps are as follows: aligning two motors with the same power and the same speed at the same height; fixing a thick copper wire between the two motors for connection so that the two motors can rotate at the same speed; then soldering the sample copper wire to the two motors with tin wire; using a rubber-tipped dropper to evenly apply the silk fibroin solution on the surface of the sample copper wire; powering on the motor so that the copper wire coated with silk fibroin rotates with the motor; turning off the power, removing the sample, and drying it with an infrared drying lamp; (4) placing the sample obtained in step (3) into a microwave tube furnace, opening the vacuum, introducing nitrogen gas for plasma heat treatment, so that the silk fibroin is converted into nitrogen-doped graphene and coated on the surface of the copper wire, and finally obtaining a graphene / copper wire composite material.

2. The method for preparing the nitrogen-doped graphene / copper wire high current-carrying composite material according to claim 1, characterized in that: In step (1), the diameter of the copper wire is greater than 20 microns. During the annealing of the copper wire, the hydrogen flow rate is controlled at 50 sccm, and the gas pressure is adjusted to 200-300 Pa. First, the microwave power is adjusted to 1000 W, preheated for 10 minutes, and then adjusted to 1500 W. The reaction time is 15 minutes.

3. The method for preparing the nitrogen-doped graphene / copper wire high current-carrying composite material according to claim 2, characterized in that: In step (2), the electron beam current is 150 mA, the plating time is 3 min, and the nickel film thickness is between 5-20 nm.

4. The method for preparing the nitrogen-doped graphene / copper wire high current-carrying composite material according to claim 1, characterized in that: In step (3), the motor speed is 17000 r / h, the motor power supply time is 60 s, and the baking time under the infrared baking lamp is 1 h.

5. The method for preparing the nitrogen-doped graphene / copper wire high current-carrying composite material according to claim 1, characterized in that: In step (4), the nitrogen flow rate is controlled at 50 sccm, the gas pressure is adjusted to 200-300 Pa, the microwave power is 2000 W, and the reaction time is 25 min.

6. The method for preparing the nitrogen-doped graphene / copper wire high current-carrying composite material according to claim 1, wherein in step (3), the diameter of the copper wire is 500-1000 μm.

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