Method for preparing graphene copper rod through multi-pass continuous extrusion

Abstract

The invention discloses a method for preparing a graphene copper rod by multi-pass continuous extrusion, which comprises the following steps of: mixing copper powder and graphene powder, and annealing with a copper pipe in inert gas; a continuous extrusion process is adopted, mixed powder of copper and graphene is added into a copper pipe, and the graphene copper rod is prepared through multi-pass continuous extrusion. According to the preparation method, process control and operation are convenient, the graphene copper mixed powder is loaded into the copper pipe for continuous extrusion, the preparation process of the graphene copper composite material is simplified, meanwhile, the copper pipe is beneficial to keeping the stable form of the copper powder in the extrusion process, and the complexity of process control is reduced.

Description

Technical Field

[0001] The invention belongs to the field of graphene copper composite materials, and particularly relates to a method for preparing a graphene copper rod by multi-pass continuous extrusion. Background Art

[0002] Continuous Extrusion Technology is an advanced metal forming process used to produce long-size, complex-section and high-quality metal profiles. This technology has significant efficiency and economic advantages and is widely used in the processing of aluminum, copper and their alloys. Continuous extrusion technology continuously feeds metal billets into the extrusion cavity through a rotating extrusion wheel. Under high temperature and high pressure conditions, the metal material is extruded through a die to form the required profile section. Continuous extrusion technology realizes the continuity of the production process, reduces downtime and die change time, improves production efficiency, reduces waste generation, improves material utilization, and reduces production costs. The continuous extrusion process can produce metal profiles with good surface quality and high dimensional accuracy to meet high-standard application requirements.

[0003] Graphene copper composite material has excellent mechanical and electrical properties, but the preparation of graphene copper composite material involves multiple steps, including the preparation and processing of graphene, the molding and sintering of composite material, etc., which are complex and easy to introduce impurities. Therefore, optimizing the preparation process and developing a simplified and efficient preparation method are the main problems faced by graphene copper composite materials. In addition, in the prior art, the preparation of graphene copper composite material generally involves complex process flow, such as CVD and high temperature treatment, resulting in low production efficiency, complex process control, and poor uniformity of the combination of graphene and copper matrix. In addition, powder is easily unevenly dispersed during processing, and it is difficult to ensure the mechanical properties and electrical conductivity of the final material. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing a graphene copper rod by multi-pass continuous extrusion.

[0007] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing a graphene copper rod by multi-pass continuous extrusion, characterized in that: it comprises:

[0008] Mixing copper powder and graphene powder and annealing them with a copper tube in an inert gas;

[0009] The continuous extrusion process is adopted to mix the annealed copper powder and the graphene powder and add them into the copper tube, and the graphene copper rod is obtained through multiple continuous extrusions.

[0010] As a preferred embodiment of the preparation method of the present invention, the copper powder includes electrolytic copper powder and spherical copper powder, and the particle size is 1 to 100 μm.

[0011] As a preferred embodiment of the preparation method of the present invention, the graphene powder has a particle size of 1 to 20 μm and has 1 to 3 layers.

[0012] As a preferred embodiment of the preparation method of the present invention, the copper tube is a high-purity copper tube, and the ratio of the outer diameter to the inner diameter of the copper tube is 2-4:1-3.

[0013] As a preferred embodiment of the preparation method of the present invention, the annealing time is 1 hour.

[0014] As a preferred embodiment of the preparation method of the present invention, the continuous extrusion process is to preheat the cavity temperature to 400-700°C, feed the sealed copper tube into the extrusion wheel, and extrusion speed is 2-6rpm to obtain a rod blank with a diameter of 6-12mm, which is cooled by continuous cooling water.

[0015] As a preferred embodiment of the preparation method of the present invention, the number of extrusions in the multiple-pass continuous extrusion is 2 to 6 passes.

[0016] As a preferred embodiment of the preparation method of the present invention, the powder mixing time is 4 to 8 hours.

[0017] As a preferred embodiment of the preparation method of the present invention, the inert gas is a mixed gas of argon and hydrogen, wherein the gas flow rates of argon and hydrogen are 400-500 sccm and 50-100 sccm respectively; and the annealing temperature is 350-450°C.

[0018] As a preferred embodiment of the preparation method of the present invention, the preheating temperature of the cavity is 600-700°C.

[0019] Beneficial effects of the present invention:

[0020] (1) The process control and operation of the present invention are convenient. By loading the mixed powder of graphene copper into a copper tube for continuous extrusion, the preparation process of the graphene copper composite material is simplified. At the same time, the copper tube also helps the copper powder to maintain a stable shape during the extrusion process, reducing the complexity of process control.

[0021] (2) The present invention reduces production costs and losses. Direct extrusion of copper powder is prone to powder scattering and material waste. Copper tube coating can reduce material loss and improve material utilization. At the same time, it reduces the wear and maintenance requirements of the extrusion equipment, thereby reducing production costs.

[0022] (3) The present invention uses a few-layer graphene as a reinforcement phase, and the conductivity of the copper rod prepared is equivalent to that of pure copper and the tensile strength is increased by more than 50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0024] Figure 1 This is an electron microscope image of the graphene copper rod prepared in Example 1 of the present invention.

[0025] Figure 2 This is an electron microscope image of the graphene copper rod prepared in Example 2 of the present invention.

[0026] Figure 3 This is an electron microscope image of the graphene copper rod prepared in Example 3 of the present invention.

[0027] Figure 4 This is an electron microscope image of the graphene copper rod prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0031] Unless otherwise specified, all raw materials used in the examples of the present invention are commercially available, as shown in Table 1 for details.

[0032] Table 1

[0033]

[0034] Example 1

[0035] (1) Prepare copper tube and copper powder raw materials, and put copper powder and graphene powder into a V-type mixer for mixing, the mixing time is 4 hours, and the graphene content is 0.05wt%; spherical copper powder is used with a copper powder particle size of 20μm, a graphene powder particle size of 10μm, and a layer number of 1-3 layers. The outer diameter of the copper tube is 8mm and the inner diameter is 6mm.

[0036] (2) The copper tube and the graphene copper mixed powder are placed in a mixed gas of argon and hydrogen for annealing at a gas flow rate of 500 sccm and 50 sccm respectively, and the annealing temperature is 350° C. to remove the oxide layer on the inner and outer surfaces of the copper tube and the surface of the copper powder.

[0037] (3) After annealing, the graphene-copper mixed powder is poured into the copper tube. Before pouring the copper powder, the outlet of the copper tube on the other side is sealed. During the filling of the copper powder, the gap between the copper-graphene mixed powder is minimized by knocking and vibrating. After the filling is completed, the inlet is sealed.

[0038] (4) The temperature of the continuous extrusion cavity is preheated to 600°C, and the sealed copper tube is fed into the extrusion wheel at an extrusion speed of 2 rpm to obtain a rod blank with a diameter of 8 mm, which is then cooled by continuous cooling water.

[0039] (5) After the initial extrusion is completed, the temperature of the continuous extrusion cavity is preheated to 400°C, and an 8 mm copper rod is fed into the extrusion wheel at an extrusion speed of 4 rpm to extrude a graphene copper rod having a diameter of 8 mm. This process is repeated 4 times (the copper rod extruded initially is continuously extruded again, and each extrusion is counted as one time) to obtain the graphene copper rod.

[0040] Example 2

[0041] The difference from Example 1 is that step (5) is repeated 6 times.

[0042] Example 3

[0043] The difference from Example 2 is that the annealing temperature in step (2) is 450°C.

[0044] Example 4

[0045] (1) Prepare copper tube and copper powder raw materials, and put copper powder and graphene powder into a ball mill for mixing, the mixing time is 5 hours, and the graphene content is 0.05wt%; electrolytic copper powder is used, and the copper powder particle size is 70μm, the graphene powder particle size is 20μm, and the number of layers is 1-3. The outer diameter of the copper tube is 8mm and the inner diameter is 6mm.

[0046] (2) The copper tube and the graphene copper mixed powder are placed in a mixed gas of argon and hydrogen for annealing at a gas flow rate of 500 sccm and 50 sccm respectively, and an annealing temperature of 400° C. to remove the oxide layer on the inner and outer surfaces of the copper tube and the surface of the copper powder.

[0047] (3) After annealing, the graphene-copper mixed powder is poured into the copper tube. Before pouring the copper powder, the outlet of the copper tube on the other side is sealed. During the filling of the copper powder, the gap between the copper-graphene mixed powder is minimized by knocking and vibrating. After the filling is completed, the inlet is sealed.

[0048] (4) The temperature of the continuous extrusion cavity is preheated to 700°C, and the sealed copper tube is fed into the extrusion wheel at an extrusion speed of 3 rpm to obtain a rod blank with a diameter of 8 mm, which is then cooled by continuous cooling water.

[0049] (5) After the initial extrusion is completed, the temperature of the continuous extrusion cavity is preheated to 400°C, and the 8 mm copper rod is fed into the extrusion wheel. The extrusion speed is 4 rpm, and the graphene copper rod with the same diameter of 8 mm is extruded. This is repeated for 6 times.

[0050] Example 5

[0051] The difference from Example 1 is that the copper powder in step (1) is electrolytic copper powder.

[0052] Example 6

[0053] The difference from Example 5 is that the graphene content in step (1) is 0.2 wt %.

[0054] Example 7

[0055] The difference from Example 3 is that the graphene content in step (1) is 0.1 wt %.

[0056] Example 8

[0057] The performance of the graphene copper rods prepared in Examples 1 to 7 was tested:

[0058] Take several copper rods with a length of not less than 1000mm and perform simple hammering and straightening. Fix the copper rods on the test bench and provide a certain preload. The test gauge length is 1000mm. Take a small section of copper rods from several copper rods and use the density method to test the average diameter of the copper rods. Input the test data into the software to calculate the conductivity.

[0059] The tensile strength test of the copper rod is carried out using a universal testing machine. A copper rod with a gauge length of not less than 10 cm is fixed on the universal testing machine, and the machine test directly displays the results.

[0060] Table 2

[0061]

[0062] It can be seen from the table that embodiment 3 is the best embodiment of the present invention. Figures 1 to 4 These are electron microscope images of graphene copper rods prepared in Examples 1 to 4 of the present invention.

[0063] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the present invention.

Claims

1. A method for preparing a graphene copper rod by multi-pass continuous extrusion, characterized in that: include, The copper powder and graphene powder are mixed and then annealed with a copper tube in an inert gas; The continuous extrusion process is adopted to mix the annealed copper powder and the graphene powder and add them into the copper tube, and the graphene copper rod is obtained through multiple continuous extrusions.

2. The method according to claim 1, characterized in that: The copper powder includes electrolytic copper powder and spherical copper powder, and the particle size is 1 to 100 μm.

3. The method according to claim 1, characterized in that: The graphene powder has a particle size of 1 to 20 μm and 1 to 3 layers.

4. The method according to claim 1, characterized in that: The copper tube is a high-purity copper tube, and the ratio of the outer diameter to the inner diameter of the copper tube is 2-4:1-3.

5. The method according to claim 1, characterized in that: The annealing time is 1 hour.

6. The method according to claim 1, characterized in that: The continuous extrusion process is to preheat the cavity temperature to 400-700°C, feed the sealed copper tube into the extrusion wheel, and extrusion speed is 2-6rpm to obtain a rod blank with a diameter of 6-12mm, which is cooled by continuous cooling water.

7. The method according to claim 1, characterized in that: In the multi-pass continuous extrusion, the number of extrusion passes is 2 to 6 passes.

8. The method according to claim 2 or 3, characterized in that: The powder mixing time is 4 to 8 hours.

9. The method according to claim 1, characterized in that: The inert gas is a mixed gas of argon and hydrogen, wherein the gas flow rates of argon and hydrogen are 400-500 sccm and 50-100 sccm respectively; the annealing temperature is 350-450°C.

10. The method according to claim 6, characterized in that: The cavity preheating temperature is 600-700°C.

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