Copper-based electrical contact composite material capable of enhancing electrical conductivity and thermal conductivity through cobalt-mediated interface engineering and preparation method of copper-based electrical contact composite material

Abstract

The invention relates to the technical field of electrical contact materials, in particular to a copper-based electrical contact composite material for enhancing electric conductivity and heat conductivity through cobalt-mediated interface engineering and a preparation method of the copper-based electrical contact composite material. (2) adding the deoiled copper powder and a conductive polymer into an initiator solution or a buffer solution; (3) filtering and collecting the polymer and the cobalt-coated copper powder; (4) drying the collected composite material precursor; and (5) carrying out hot pressing or pressing sintering to obtain the modified copper-based electrical contact material. A conductive polymer and cobalt ions are complexed and assembled on the surface of copper powder, then high-temperature sintering is performed to obtain the copper-based composite material, and cobalt catalyzes formation of high-quality graphene; the heteroatom-doped graphene is prepared through high-temperature carbonization of the conductive polymer, and the carrier concentration and the interface energy band structure of the material are optimized; and the cobalt bridging copper-carbon interface reduces electron and phonon scattering and improves the electrical conductivity and thermal conductivity of the composite material.

Description

Technical Field

[0001] This invention relates to the field of electrical contact materials technology, and in particular to a copper-based electrical contact composite material and its preparation method that enhances electrical and thermal conductivity through cobalt-mediated interface engineering. Background Technology

[0002] As a core component of electrical switches, the performance of electrical contact materials directly determines the conductivity, arc erosion resistance, and service life of the equipment. Copper-based electrical contact materials, due to copper's high conductivity and arc resistance, are widely used in medium- and low-voltage switch applications such as circuit breakers and relays. However, as electrical equipment develops towards higher voltage and longer lifespan, traditional copper-based electrical contact materials exhibit defects such as easy oxidation of copper at high temperatures under high voltage and high frequency conditions, making it difficult to meet the performance requirements of high-performance electrical contact materials. In recent years, graphene, due to its ultra-high conductivity (>6000 S / cm), mechanical strength (130 GPa), and thermal stability (thermal conductivity 5000 W / m·K), has been more widely introduced as a filler into electrical contact material systems. However, existing processes or technologies often employ mechanical mixing or chemical plating to directly add graphene to a copper matrix. Due to graphene's high specific surface area and the van der Waals forces between graphene sheets, it is prone to agglomeration, resulting in uneven graphene dispersion and an inability to form an effective bond with the metal matrix. Furthermore, graphene is easily peeled off and fails during high-temperature sintering, becoming stress concentration points and causing a reverse deterioration in material properties: on the one hand, graphene agglomerates hinder electron transport paths, increasing contact resistance and decreasing conductivity. Simultaneously, the mismatch in thermal expansion coefficients induces microcracks, leading to a deterioration in the arc ablation rate. On the other hand, the low interfacial physical adsorption binding energy makes graphene easily peeled off under high-temperature sintering or arc impact, forming stress concentration points and accelerating matrix fatigue fracture, resulting in a decrease in material hardness.

[0003] Therefore, the uniform dispersion of graphene in copper contact materials is crucial for enhancing the overall performance of copper-based electrical contact materials. Thus, developing a novel composite technology that can achieve uniform graphene dispersion, strong interfacial bonding, and synergistic performance advantages of the copper matrix has become a key direction for overcoming the performance bottlenecks of copper-based electrical contact materials.

[0004] There are various existing methods for preparing copper-based electrical contact materials, but the existing technical solutions for preparing copper-based electrical contact materials still have shortcomings.

[0005] For example, the invention patent with publication number CN110484803A discloses a mixed dispersion reinforced copper-tungsten-chromium electrical contact material and its preparation method. The mixed dispersion reinforced copper-tungsten-chromium electrical contact material prepared by this method has poor interfacial bonding between graphene and copper matrix because the graphene is not surface treated.

[0006] For example, the invention patent with publication number CN105609159A discloses a copper-plated graphene-reinforced copper-based electrical contact material and its preparation method. This scheme uses magnetron sputtering to process graphene with copper, but magnetron sputtering is costly and difficult to mass-produce, and it also has problems such as uneven coating and poor adhesion.

[0007] For example, the invention patent with publication number CN110157932A discloses a method for preparing graphene-modified copper-based electrical contact materials based on in-situ synthesis. This method uses polyethylene glycol or polyethylene as a solid polymer carbon source to generate graphene in situ, and then improves the interfacial bonding strength by ball milling. Although it ensures uniform dispersion and interfacial bonding in the graphene copper matrix, the process steps are too complicated and the cost is high. Summary of the Invention

[0008] The purpose of this invention is to address the problems of decreased conductivity and weak interfacial bonding caused by graphene agglomeration in traditional copper-based electrical contact materials, and to provide a copper-based electrical contact composite material and its preparation method that enhances electrical and thermal conductivity through cobalt-mediated interface engineering. The aim is to achieve in-situ generation of graphene on the surface of a copper matrix through technologies such as "degreasing the surface of copper particles," "coordination bonding of conductive polymers, cobalt salts, and copper," and "cobalt-catalyzed graphitization engineering," thereby strengthening the interfacial bonding between graphene and the copper matrix and significantly improving the material's electrical and thermal conductivity.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A method for preparing a copper-based electrical contact composite material with enhanced electrical and thermal conductivity through cobalt-mediated interface engineering includes the following steps:

[0011] (1) Degreasing treatment of the surface of copper particles;

[0012] (2) The degreased copper particles, cobalt salt and conductive polymer precursor are placed in an initiator solution or buffer solution to react and form a polymer and cobalt-coated copper powder composite material.

[0013] (3) Remove the solvent and collect the polymer and cobalt-coated copper powder composite material;

[0014] (4) The collected polymer and cobalt-coated copper powder composite material were dried to obtain precursor composite powder;

[0015] (5) The precursor composite powder is subjected to hot pressing or pressing sintering treatment to obtain the copper-based electrical contact composite material.

[0016] Preferably, in the above preparation method, the specific operation of the degreasing treatment in step (1) is as follows: the copper metal particles are placed in an ethanol solution and ultrasonically treated, then rinsed with deionized water, pure ethanol and deionized water 1-5 times in sequence, and then dried to obtain degreased copper particles for later use.

[0017] Preferably, in the above preparation method, in step (2), the mass ratio of copper powder, cobalt salt and conductive polymer precursor is 99.4:0.5:0.1 ~ 80:10:10.

[0018] Preferably, in the above preparation method, in step (2), the cobalt salt is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, or cobalt carbonate.

[0019] Preferably, in the above preparation method, in step (2), the conductive polymer precursor is selected from at least one of dopamine hydrochloride, pyrrole, thiophene or aniline.

[0020] Preferably, in the above preparation method, in step (2), the initiator solution or buffer solution is at least one of Tris buffer solution, ammonium persulfate solution, ferric chloride solution or hydrogen peroxide solution.

[0021] Preferably, in the above preparation method, in step (2), the stirring speed of the reaction is 10-1000 rpm / min, and the reaction time is 3-48 hours.

[0022] Preferably, in the above preparation method, the hot pressing process conditions in step (5) are: temperature 600-1000℃, pressure 10-200 MPa, and time 1-5 hours.

[0023] Preferably, in the above preparation method, the pressing and sintering process conditions in step (5) are: first pressing and molding at 15-200MPa, and then sintering in an inert atmosphere at 800-1050℃ for 1-5 hours.

[0024] In addition, the present invention also provides a copper-based electrical contact composite material prepared by the above preparation method.

[0025] In summary, due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0026] 1. This invention utilizes the coordination bonding of conductive polymers, cobalt salts, and copper, along with cobalt-catalyzed graphitization engineering. By using cobalt to form strong coordination bonds between the surface of copper particles and the conductive polymer coating, a uniform polydopamine coating and cobalt are formed on the surface of the copper particles. During the high-temperature sintering process, high-quality graphene is formed, and the z-heteroatom doping in the graphene optimizes the carrier concentration and interfacial band structure. Furthermore, the cobalt bridging interface reduces electron and phonon scattering. This improves upon the problems of graphene agglomeration and uneven dispersion leading to performance degradation in graphene-copper composite electrical contact materials prepared by conventional physical-mechanical mixing and chemical plating methods. It provides an effective interface design and process solution to overcome the bottleneck of multi-performance synergy in metal-based composite materials.

[0027] 2. This invention employs a conductive polymer complexed with cobalt ions and assembled onto the surface of copper powder, followed by high-temperature sintering to obtain a copper-based composite material. Cobalt catalyzes the formation of high-quality graphene. Heteroatom-doped graphene is prepared by high-temperature carbonization of the conductive polymer, optimizing the material's carrier concentration and interfacial band structure. Furthermore, cobalt bridging of the copper-carbon interface reduces electron and phonon scattering, improving the composite material's electrical and thermal conductivity. Experimental data shows that the copper-based electrical contact composite material prepared in this application achieves an electrical conductivity of 97.35% IACS and a thermal conductivity as high as 588 W·m. -1 ·k -1 .

[0028] 3. The contact material of the present invention has a simple process, is easy to operate, and has a short production cycle, which is conducive to its widespread application. Attached Figure Description

[0029] Figure 1 SEM image of the surface of copper particles uniformly coated with conductive polymer and cobalt salt.

[0030] Figure 2 This is a SEM cross-sectional view of the graphene-copper composite electrical contact material prepared in this application.

[0031] Figure 3 The diagram shows the electrical conductivity and thermal conductivity of the electrical contact materials prepared in Examples 1-4 and Comparative Examples 1-4. Detailed Implementation

[0032] This invention provides a method for preparing a heteroatom-doped graphene copper composite electrical contact material based on cobalt-catalyzed graphitization using conductive polymers in situ. This method enhances the electrical and thermal conductivity of the copper-based electrical contact composite material through cobalt-mediated interface engineering. The specific preparation method includes the following steps:

[0033] (1) Degreasing treatment of copper particles: The copper metal particles are placed in an ethanol solution and ultrasonically treated. Then, they are rinsed with deionized water, pure ethanol and deionized water 1-5 times in sequence to remove the grease formed on the surface of the copper particles during the production process. Then, they are dried to obtain degreased copper particles for use.

[0034] (2) The degreased copper particles, cobalt salt and conductive polymer precursor are placed in an initiator solution or buffer solution at a mass ratio of 99.4:0.5:0.1 ~ 80:10:10 and reacted at a rate of 10-1000 rpm / min for 3-48 hours to form a polymer and cobalt-coated copper powder composite material.

[0035] Wherein, the cobalt salt is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, or cobalt carbonate; the conductive polymer precursor is selected from at least one of dopamine hydrochloride, pyrrole, thiophene, or aniline; and the initiator solution or buffer solution is at least one of Tris buffer solution, ammonium persulfate solution, ferric chloride solution, or hydrogen peroxide solution.

[0036] (3) Remove the solvent and collect the polymer and cobalt-coated copper powder composite material;

[0037] (4) The collected polymer and cobalt-coated copper powder composite material is dried at a temperature of 50-150 °C for 0.5-24 h to obtain precursor composite powder.

[0038] (5) The precursor composite powder is subjected to hot pressing or pressing sintering to obtain the copper-based electrical contact composite material. In this step, whether the precursor composite powder is subjected to hot pressing or pressing sintering, the copper-based electrical contact composite material can be obtained. If hot pressing is selected, the process conditions are: temperature 600-1000℃, pressure 10-200 MPa, time 1-5 hours. If pressing sintering is selected, the process conditions are: first press at 15-200 MPa, then sinter in an inert atmosphere at 800-1050℃ for 1-5 hours. Those skilled in the art can choose which processing technology to use to process the precursor composite powder within this range according to the actual situation.

[0039] To more clearly illustrate the present invention, the following specific embodiments will be used to further explain the invention.

[0040] Example 1

[0041] (1) Degreasing treatment of copper particles: Copper metal particles (particle size 200 mesh, dendritic morphology) are placed in pure ethanol solution for ultrasonic treatment, and then rinsed with deionized water, pure ethanol and deionized water three times in sequence. Then, they are vacuum dried at 80 °C for 16 h to obtain degreased copper particles (called degreased copper particles) for use.

[0042] (2) Dissolve 1.2114 g of tris(hydroxy)aminomethane in 450 ml of deionized water, adjust the pH to 8.5 with hydrochloric acid, and make up to 500 ml in a volumetric flask to prepare a Tris buffer solution; weigh out degreased copper particles, cobalt nitrate hexahydrate, and dopamine hydrochloride in a mass ratio of 99.4:0.5:0.1, put 99.4 g of degreased copper particles, 0.5 g of cobalt nitrate hexahydrate, 0.1 g of dopamine hydrochloride and 300 ml of the prepared Tris buffer solution into a 500 ml beaker, and react with magnetic stirring (100 rpm / min) for 10 h to form a polymer and cobalt-coated copper powder composite material;

[0043] (3) Vacuum filtration step (2) The polymer and cobalt-coated copper powder composite material obtained after the reaction were then rinsed with deionized water 4 times and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain cobalt-polydopamine copper composite powder.

[0044] (4) The cobalt-polydopamine copper composite powder was dried in a vacuum drying oven at 80 °C for 12 h to obtain the precursor cobalt-polydopamine copper composite powder.

[0045] (5) Take the precursor composite powder obtained in step (4), place it in a graphite mold, and process it by hot pressing sintering. The hot pressing sintering conditions are: first press it at 10 MPa, and then sinter it in an inert atmosphere at 1000℃ for 1 hour; to obtain a copper-based electrical contact material with high conductivity and high thermal conductivity.

[0046] Example 2

[0047] (1) Degreasing treatment of copper particles: Copper metal particles (500 mesh, spherical shape) were placed in pure ethanol solution for ultrasonic treatment, and then rinsed with deionized water, pure ethanol and deionized water 4 times in sequence. Then, they were vacuum dried at 60 °C for 24 h to obtain degreased copper particles for use.

[0048] (2) Dissolve 4.564 g of ammonium persulfate in 450 ml of deionized water and make up to 500 ml in a volumetric flask to prepare an ammonium persulfate solution; weigh out degreased copper particles, cobalt chloride and pyrrole in a mass ratio of 85:10:5, put 85 g of degreased copper particles, 10 g of cobalt chloride, 5 g of pyrrole and 400 ml of the prepared ammonium persulfate solution into a 500 ml beaker, and react with magnetic stirring (50 rpm / min) for 12 h to form a polymer and cobalt-coated copper powder composite material;

[0049] (3) Vacuum filtration step (2) The polymer and cobalt-coated copper powder composite material obtained after the reaction were then rinsed with deionized water 5 times and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain cobalt-polypyrrole copper composite powder.

[0050] (4) Dry the cobalt-polypyrrole copper composite powder in a vacuum drying oven at 100 °C for 8 h to obtain the precursor cobalt-polypyrrole copper composite powder;

[0051] (5) Take the precursor composite powder obtained in step (4), place it in a graphite mold, and process it by hot pressing sintering. The hot pressing sintering conditions are: first press it at 200 MPa, and then sinter it in an inert atmosphere at 600℃ for 5 hours; to obtain a copper-based electrical contact material with high conductivity and high thermal conductivity.

[0052] Example 3

[0053] (1) Degreasing treatment of copper particles: Copper metal particles (300 mesh, flake-shaped) were placed in pure ethanol solution for ultrasonic treatment, then rinsed with deionized water, pure ethanol and deionized water 5 times in sequence, and then vacuum dried at 100 °C for 8 h to obtain degreased copper particles for use.

[0054] (2) Dissolve 3.244 g of ferric chloride in 450 ml of deionized water, adjust the pH to 6.0 with sodium hydroxide, and make up to 500 ml in a volumetric flask to prepare a ferric chloride solution; weigh out degreased copper particles, cobalt sulfate and thiophene in a mass ratio of 92.5:2.5:5; put 92.5 g of degreased copper particles, 2.5 g of cobalt sulfate, 5 g of thiophene and 200 ml of the prepared ferric chloride solution into a 500 ml beaker, and react with magnetic stirring (1000 rpm / min) for 3 h to form a polymer and cobalt-coated copper powder composite material;

[0055] (3) Vacuum filtration step (2) The polymer and cobalt-coated copper powder composite material obtained after the reaction were then rinsed three times with deionized water and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain cobalt-polythiophene copper composite powder.

[0056] (4) Dry the cobalt-polythiophene copper composite powder collected in step (3) at 120 °C in a vacuum drying oven for 6 h to obtain the precursor cobalt-polythiophene copper composite powder.

[0057] (5) Take the precursor composite powder obtained in step (4) and process it by pressing and sintering process. Specifically, place the precursor composite powder into a steel mold and press it into a block with a pressure of 15 MPa. Then sinter it in an inert atmosphere at 1050 °C for 1 h to obtain a copper-based electrical contact material with high conductivity and high thermal conductivity.

[0058] Example 4

[0059] (1) Degreasing treatment of copper particles: Copper metal particles (200 mesh, rod-shaped) were placed in pure ethanol solution for ultrasonic treatment, and then rinsed with deionized water, pure ethanol and deionized water 4 times in sequence. Then, they were vacuum dried at 80 °C for 16 h to obtain degreased copper particles for use.

[0060] (2) Take 0.34 g of hydrogen peroxide solution into 450 ml of deionized water and make up to 500 ml in a volumetric flask to prepare hydrogen peroxide solution; weigh out degreased copper particles, cobalt carbonate and aniline in a mass ratio of 80:10:10, put 80 g of degreased copper particles, 10 g of cobalt carbonate, 10 g of aniline and 400 ml of the prepared hydrogen peroxide solution into a 500 ml beaker, and react with magnetic stirring (10 rpm / min) for 48 h to form a polymer and cobalt-coated copper powder composite material;

[0061] (3) Vacuum filtration step (2) The polymer and cobalt-coated copper powder composite material obtained after the reaction were then rinsed twice with deionized water and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain cobalt-polyaniline copper composite powder.

[0062] (4) Dry the cobalt-polyaniline copper composite powder collected in step (3) at 60 °C in a vacuum drying oven for 20 h to obtain the precursor cobalt-polyaniline copper composite powder.

[0063] (5) Take the precursor composite powder obtained in step (4) and process it by pressing and sintering process. Specifically, place the precursor composite powder into a steel mold and press it into a block with a pressure of 200 MPa. Then sinter it in an inert atmosphere at 800 ℃ for 5 h to obtain a copper-based electrical contact material with high conductivity and high thermal conductivity.

[0064] Comparative Example 1

[0065] (1) Degreasing treatment of copper particles: Copper metal particles (300 mesh, flake-shaped) were placed in pure ethanol solution for ultrasonic treatment, rinsed with deionized water, pure ethanol and deionized water 5 times in sequence, and vacuum dried at 100 °C for 8 h to obtain degreased copper particles for use.

[0066] (2) Take 100g of degreased copper powder obtained in step (1) (i.e. copper particles after degreasing) and process it by pressing and sintering process. Specifically, place 100g of degreased copper powder into a steel mold and press it into a block with a pressure of 15 MPa. Then sinter it at 1050 ℃ in an inert atmosphere for 1 h to obtain copper-based electrical contact material.

[0067] Comparative Example 2

[0068] (1) Degreasing treatment of copper particles: Copper metal particles (300 mesh, flake-shaped) were placed in pure ethanol solution for ultrasonic treatment, rinsed with deionized water, pure ethanol and deionized water 5 times in sequence, and vacuum dried at 100 ℃ for 8 h for later use to obtain degreased copper particles.

[0069] (2) Dissolve 3.244 g of ferric chloride in 450 ml of deionized water, adjust the pH to 6.0 with sodium hydroxide, and make up to 500 ml in a volumetric flask to prepare a ferric chloride solution; weigh out degreased copper particles and thiophene in a mass ratio of 92.5:5; put 92.5 g of degreased copper particles, 5 g of thiophene and 200 ml of the prepared ferric chloride solution into a 500 ml beaker and stir with a magnetic stirrer (1000 rpm / min) for 3 h to form a polymer-coated copper powder composite material;

[0070] (3) Vacuum filtration step (2) The polymer-coated copper powder composite material obtained after the reaction was then rinsed three times with deionized water and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain polythiophene copper composite powder.

[0071] (4) Dry the polythiophene copper composite powder collected in step (3) at 120 °C in a vacuum drying oven for 6 hours to obtain the precursor polythiophene copper composite powder.

[0072] (5) Take the precursor composite powder obtained in step (4) and process it by pressing and sintering process. Specifically, place the precursor composite powder into a steel mold and press it into a block with a pressure of 15 MPa. Then sinter it in an inert atmosphere at 1050 °C for 1 h to obtain copper-based electrical contact material.

[0073] Comparative Example 3

[0074] (1) Degreasing treatment of copper particles: Copper metal particles (300 mesh, flake-shaped) were placed in pure ethanol solution for ultrasonic treatment, and then rinsed with deionized water, pure ethanol and deionized water 5 times in sequence. Then, they were vacuum dried at 100 °C for 8 h for later use to obtain degreased copper particles.

[0075] (2) Weigh out degreased copper particles and cobalt sulfate at a mass ratio of 92.5:2.5, put them into 200 ml of deionized water, and react with magnetic stirring (30 rpm / min) for 20 h to form a cobalt-copper powder composite material;

[0076] (3) Vacuum filtration step (2) After the reaction, the cobalt-copper powder composite material obtained is collected in a petri dish after vacuum filtration to obtain cobalt-copper composite powder;

[0077] (4) Dry the cobalt-copper composite powder collected in step (3) at 120 °C in a vacuum drying oven for 6 h to obtain the precursor cobalt-copper composite powder.

[0078] (5) Take the precursor composite powder obtained in step (4) and process it by pressing and sintering process. Specifically, place the precursor composite powder into a steel mold and press it into a block with a pressure of 15 MPa. Then sinter it in an inert atmosphere at 1050 °C for 1 h to obtain copper-based electrical contact material.

[0079] Comparative Example 4:

[0080] (1) Dissolve 3.244 g of ferric chloride in 450 ml of deionized water, adjust the pH to 6.0 with sodium hydroxide, and make up to 500 ml in a volumetric flask to prepare a ferric chloride solution; weigh unremoved copper particles, cobalt sulfate and thiophene in a mass ratio of 92.5:2.5:5; put 92.5 g of unremoved copper particles, 2.5 g of cobalt sulfate, 5 g of thiophene and 200 ml of the prepared ferric chloride solution into a 500 ml beaker, and react with magnetic stirring (1000 rpm / min) for 3 h to form a polymer and cobalt-coated copper powder composite material;

[0081] (2) Vacuum filtration step (2) The polymer and cobalt-coated copper powder composite material obtained after the reaction were then rinsed three times with deionized water and finally rinsed with ethanol. The powder after vacuum filtration was collected in a petri dish to obtain cobalt-polythiophene copper composite powder.

[0082] (3) Dry the cobalt-polythiophene copper composite powder collected in step (3) at 120 °C in a vacuum drying oven for 6 h to obtain the precursor cobalt-polythiophene copper composite powder.

[0083] (4) Take the precursor composite powder obtained in step (4) and process it by pressing and sintering process. Specifically, place the precursor composite powder into a steel mold and press it into a block with a pressure of 15 MPa. Then sinter it in an inert atmosphere at 1050 °C for 1 h to obtain copper-based electrical contact material.

[0084] Performance testing

[0085] 1. The precursor composite powder prepared in step (4) of Examples 1-4 was examined by scanning electron microscopy. The results are as follows: Figure 1 As shown, Figure 1 In (a), a rough and uniformly distributed surface is clearly observed. Figure 1 (b) is Figure 1 (a) shows a magnified image where the conductive polymer and regular particles on its surface are clearly visible. These regular particles are cobalt salts.

[0086] 2. SEM images of the cross-sections of the highly conductive and highly thermally conductive copper-based electrical contact materials obtained after processing in Examples 1-4 are shown below. Figure 2 As shown. Figure 2 (a) Clearly observed heteroatom-doped graphene with wrinkles is uniformly distributed and well bonded to the copper surface through the interface bridging effect of cobalt. Figure 2 (b) is Figure 2 (a) shows a magnified image where heteroatom-doped graphene is clearly distributed uniformly on the surface of the copper matrix, and it can be seen that there are no pores in the copper matrix. This indicates that reducing porosity can reduce electron and phonon scattering and improve the electrical and thermal conductivity of the composite material.

[0087] 3. The room temperature conductivity of the copper-based electrical contact materials prepared in Examples 1-4 and Comparative Examples 1-3 was tested using the four-probe method: The resistivity (ρ) of the samples was measured using a four-probe resistance meter (RTS-11, Guangzhou Four-Probe Technology Co., Ltd.). The conductivity of the composite material was calculated using the basic formula σ=1 / ρ, and finally, the IACS was calculated by comparing it with the conductivity of internationally annealed copper. The conductivity of the copper-based electrical contact materials prepared in Examples 1-4 and Comparative Examples 1-3 is shown in Table 1.

[0088] 4. The room temperature thermal conductivity of the prepared copper-based electrical contact material was tested:

[0089] The density of the sample was tested using a self-made density meter (Archimedes method); the thermal diffusivity and specific heat capacity of the sample were tested using a laser thermal conductivity meter (XFA600); and the thermal conductivity was calculated using the formula (…). The thermal conductivity was calculated. The thermal conductivity of the copper-based electrical contact materials prepared in Examples 1-4 and Comparative Examples 1-4 is shown in Table 1:

[0090] Table 1. Electrical conductivity and thermal conductivity of the copper-based electrical contact materials prepared in Examples 1-4 and Comparative Examples 1-4

[0091] Electrical conductivity (% IACS) <![CDATA[Thermal conductivity (W·m -1 ·k -1 )]]> Example 1 97.35 588 Example 2 96.88 555 Example 3 96.48 537 Example 4 94.63 525 Comparative Example 1 88.73 391 Comparative Example 2 91.28 425 Comparative Example 3 85.31 361 Comparative Example 4 92.39 458

[0092] As can be seen from Table 1, the electrical conductivity and thermal conductivity of the copper-based electrical contact materials prepared in Examples 1-4 are better than those prepared in Comparative Examples 1-4.

[0093] In addition, the electrical conductivity and thermal conductivity data of the copper-based electrical contact materials prepared in Comparative Examples 1-4 and Examples 1-4 are shown in the figure below. Figure 3 As shown.

[0094] from Figure 3 (a) It was clearly observed that the conductivity of Example 4 was increased by 9.7% compared to Comparative Example 1, and the conductivity of Comparative Example 2 was increased by 2.9% compared to Comparative Example 1. This is because the conductive polymer was carbonized at high temperature to form heteroatom-doped graphene, which optimized the carrier concentration of the material. However, due to the persistent interface problem between copper and carbon, the improvement in conductivity was limited. The conductivity of Comparative Example 3 was actually decreased by 3.9% compared to Comparative Example 1. This is because the conductivity of cobalt is lower than that of copper, and the addition of cobalt reduced the conductivity of copper. As for Comparative Example 4, its conductivity... The conductivity was lower than that of Examples 1-4. This is because the copper was not degreased in the comparative examples, which reduced the strong interfacial bonding force between graphene and the copper matrix. Due to the preparation method of this application, the high-temperature sintering process catalyzes the formation of high-quality graphene, the z-heteroatom doping in the graphene optimizes the carrier concentration and interfacial band structure, and the cobalt bridging interface reduces electron and phonon scattering. As a result, the conductivity of the other examples was also improved to varying degrees compared with Comparative Examples 1-4, with an improvement of approximately 3.7% to 14.1%.

[0095] Figure 3 (b) It was clearly observed that the thermal conductivity of Example 4 was increased by 50.4% compared to Comparative Example 1, while the thermal conductivity of Comparative Example 2 was increased by 8.7% compared to Comparative Example 1. This is because the conductive polymer was carbonized at high temperature to form heteroatom-doped graphene, which optimized the carrier concentration of the material. However, due to the persistent interface problem between copper and carbon, the improvement in thermal conductivity was limited. The thermal conductivity of Comparative Example 3 was actually reduced by 7.7% compared to Comparative Example 1. This is because the thermal conductivity of cobalt is lower than that of copper, and the addition of cobalt reduced the thermal conductivity of copper. In Comparative Example 4, the lack of degreasing treatment on copper resulted in a weaker strong interface bond between graphene and the copper matrix, leading to a decrease in thermal conductivity compared to other examples. The other examples of this application also showed varying degrees of improvement in electrical conductivity compared to Comparative Example 1, Comparative Example 2, and Comparative Example 3, with improvements ranging from approximately 23.5% to 62.9%.

[0096] By comparing the electrical conductivity and thermal conductivity of the copper-based electrical contact materials prepared in Examples 1-3 and Examples 1-4, it can be found that the copper-based electrical contact materials prepared in Examples 1-4 have reduced porosity due to the uniform distribution of heteroatom-doped graphene on the surface of the copper matrix and the bridging of the copper-carbon interface by cobalt. The reduction in porosity reduces electron and phonon scattering, thereby improving the electrical conductivity and thermal conductivity of the composite material. This successfully demonstrates that the synergistic effect of cobalt salt and conductive polymer enhances the electrical conductivity and thermal conductivity of the material.

[0097] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.

Claims

1. A method for preparing a copper-based electrical contact composite material with enhanced electrical and thermal conductivity through cobalt-mediated interface engineering, characterized in that, Includes the following steps: (1) Degreasing treatment of the surface of copper particles; (2) The degreased copper particles, cobalt salt and conductive polymer precursor are placed in an initiator solution or buffer solution to react and form a polymer and cobalt-coated copper powder composite material. (3) Remove the solvent and collect the polymer and cobalt-coated copper powder composite material; (4) The collected polymer and cobalt-coated copper powder composite material were dried to obtain precursor composite powder; (5) The precursor composite powder is subjected to hot pressing or pressing sintering treatment to obtain the copper-based electrical contact composite material.

2. The preparation method according to claim 1, characterized in that, The specific operation of the degreasing treatment in step (1) is as follows: the copper metal particles are placed in an ethanol solution and ultrasonically treated, then rinsed with deionized water, pure ethanol and deionized water 1-5 times in sequence, and then dried to obtain degreased copper particles for later use.

3. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of copper powder, cobalt salt and conductive polymer precursor is 99.4:0.5:0.1 ~ 80:10:

10.

4. The preparation method according to claim 1, characterized in that, In step (2), the cobalt salt is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, or cobalt carbonate.

5. The preparation method according to claim 1, characterized in that, In step (2), the conductive polymer precursor is selected from at least one of dopamine hydrochloride, pyrrole, thiophene or aniline.

6. The preparation method according to claim 1, characterized in that, In step (2), the initiator solution or buffer solution is at least one of Tris buffer solution, ammonium persulfate solution, ferric chloride solution or hydrogen peroxide solution.

7. The preparation method according to claim 1, characterized in that, In step (2), the stirring speed of the reaction is 10-1000 rpm / min, and the reaction time is 3-48 hours.

8. The preparation method according to claim 1, characterized in that, In step (5), the hot pressing process conditions are: temperature 600-1000℃, pressure 10-200 MPa, and time 1-5 hours.

9. The preparation method according to claim 1, characterized in that, In step (5), the pressing and sintering process conditions are as follows: first, press the material at 15-200 MPa, and then sinter it in an inert atmosphere at 800-1050℃ for 1-5 hours.

10. A copper-based electrical contact composite material prepared by any one of claims 1-9.

Images