Preparation method of high-conductivity copper-based nano-composite contact material, high-conductivity copper-based nano-composite contact material and application of high-conductivity copper-based nano-composite contact material

Abstract

The invention provides a preparation method of a high-conductivity copper-based nano-composite contact material, the high-conductivity copper-based nano-composite contact material and application of the high-conductivity copper-based nano-composite contact material, the preparation method comprises the steps that a chemical co-reduction method is adopted to generate a nano-silver coating layer on the surface of copper powder in situ, graphene oxide is reduced at the same time, and silver-coated copper / reduced graphene oxide composite powder is obtained; carrying out ultrasonic-assisted ball-milling mixing with nano aluminum oxide; performing spark plasma sintering; performing hot extrusion forming; and annealing treatment. The nano silver-graphene-copper gradient interface structure is constructed, the conductive performance and the arc ablation resistance are synergistically improved, the room temperature conductivity reaches 103-107% IACS, the tensile strength reaches 350-420 MPa, and the nano silver-graphene-copper gradient interface structure is suitable for electric power fitting connection wire clamps and connectors.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite technology, specifically to a method for preparing highly conductive copper-based nanocomposite contact materials, the highly conductive copper-based nanocomposite contact materials and their applications, and is particularly suitable for high-requirement electrical contact applications such as power fittings, connectors and splice clamps. Background Technology

[0002] Electrical contact materials are core components of critical parts in power systems, such as switches, relays, coupling clamps, and connectors. Their performance directly determines the safety, reliability, and service life of electrical equipment. Ideal electrical contact materials need to possess excellent electrical conductivity, good thermal conductivity, high hardness, low contact resistance, excellent resistance to arc erosion, and good resistance to mechanical wear.

[0003] Pure copper, as a traditional electrical contact material, possesses excellent electrical conductivity, achieving a room temperature conductivity of 5.8 × 10⁻⁶. 7 S / m, or 100% IACS. However, pure copper has low hardness and insufficient resistance to arc erosion. Under the action of an electric arc, it is prone to melting, splashing, and transfer, which seriously affects the reliability and service life of electrical contacts. Especially in the field of power fittings, splicing clamps and connectors need to withstand high current and frequent switching operations for a long time, and pure copper materials are difficult to meet the increasingly stringent usage requirements.

[0004] While silver-based electrical contact materials such as Ag-SnO2 and Ag-CdO possess excellent resistance to arc erosion, silver resources are scarce and expensive, and cadmium oxide is toxic, failing to meet the requirements of green and environmentally friendly development. Therefore, the development of high-performance, low-cost copper-based electrical contact materials has become an urgent need for industry development.

[0005] In recent years, graphene has become an ideal choice for reinforcing metal matrices due to its superior electrical, thermal, and mechanical properties. Graphene boasts a carrier mobility as high as 2 × 10⁻⁶. 5 cm 2 ·V -1 ·s -1 It is much higher than the 32 cm of pure copper. 2 V -1 ·s -1 Furthermore, graphene's temperature coefficient of resistance is much lower than that of pure copper, which is beneficial for improving the material's high-temperature conductivity. However, the poor wettability and large density difference between graphene and the copper matrix make it difficult for graphene to be uniformly dispersed in the copper matrix, resulting in insufficient interfacial bonding strength.

[0006] Chinese patent application CN118910457A discloses a copper / graphene composite material, its preparation method, and its applications. The method involves growing graphene on the surface of a mixture of copper powder and nano-magnesium oxide using chemical vapor deposition (CVD), followed by vacuum hot pressing and vacuum casting. While this method achieves good room-temperature and high-temperature electrical conductivity, it suffers from the following drawbacks: the CVD process requires sophisticated equipment, is costly, and is difficult to scale up; the vacuum casting process is complex and has stringent equipment requirements; and the material's resistance to arc erosion is not specifically enhanced, making it unsuitable for demanding applications such as power fittings.

[0007] Chinese patent application CN115351277A discloses a graphene-copper composite material, its preparation method, and its application. The method involves chemical vapor deposition (CVD) of copper powder onto the surface of the copper powder in a methane and reducing atmosphere to form graphene. However, this method also faces the limitations of CVD processes and does not solve the core problem of the interfacial bonding between graphene and the copper matrix. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for preparing highly conductive copper-based nanocomposite contact materials, the materials themselves, and their applications. This invention employs a chemical co-reduction method to generate a nano-silver coating layer in situ on the surface of copper powder, while simultaneously reducing graphene oxide. Combined with a nano-alumina reinforcing phase, and through ultrasonic-assisted ball milling dispersion, spark plasma sintering, and hot extrusion molding processes, a high-performance electrical contact material with excellent conductivity and arc erosion resistance is prepared. This material is particularly suitable for demanding applications such as power fitting clamps and connectors.

[0009] The first aspect of this invention provides a method for preparing a highly conductive copper-based nanocomposite contact material, comprising the following steps:

[0010] Step 1: Disperse copper powder in a solution containing silver ions and graphene oxide, add a reducing agent to carry out a chemical co-reduction reaction, so that the silver ions are reduced in situ on the surface of the copper powder to form a nano-silver coating layer, and at the same time, the graphene oxide is reduced to reduced graphene oxide, to obtain silver-coated copper / reduced graphene oxide composite powder.

[0011] Step 2: The silver-coated copper / reduced graphene oxide composite powder and nano-alumina powder are mixed by ultrasonic-assisted ball milling to obtain a three-phase composite powder.

[0012] Step 3: Perform spark plasma sintering on the three-phase composite powder to obtain a composite green body.

[0013] Step 4: Hot extrusion molding of the composite preform to obtain a highly conductive copper-based nanocomposite contact material.

[0014] The technical solution of this invention is based on the following design principles and technical considerations:

[0015] First, this invention creatively employs a chemical co-reduction method to simultaneously prepare a nano-silver coating layer and reduced graphene oxide. During the chemical co-reduction process, silver ions preferentially undergo a reduction reaction on the surface of copper powder, forming a uniform nano-silver coating layer. This process utilizes the characteristic that the reduction potential of copper is lower than that of silver. Due to the standard reduction potential... Higher than Silver ions are more easily reduced by the reducing agent, while the copper surface provides heterogeneous nucleation sites, promoting the directional deposition of silver nanoparticles. Simultaneously, the reducing agent reduces graphene oxide to reduced graphene oxide, removing most of the oxygen-containing functional groups and restoring the sp(s) properties of graphene. 2 Hybrid carbon network structure improves its electrical conductivity.

[0016] Second, the nano-silver coating layer constructs a crucial gradient transition interface between the copper substrate and graphene. Silver and copper form a face-centered cubic solid solution with lattice constants close to ( ). , The relatively small lattice mismatch at the interface is conducive to the formation of a semi-coherent interface. Simultaneously, silver exhibits good wettability towards graphene, effectively improving the interfacial bonding between graphene and the metal matrix. The silver layer, as a highly conductive copper-based nanocomposite contact material and its preparation method, enhances interfacial adhesion and electron transport. Silver atoms can effectively dope graphene with electrons, increasing the carrier concentration and achieving a synergistic enhancement of conductivity.

[0017] Third, the addition of nano-alumina specifically enhances the material's resistance to arc erosion. Alumina (Al2O3) possesses a high melting point (2050℃), high chemical stability, good insulation, and excellent oxidation resistance. Under the influence of an electric arc, the nano-alumina phase can act as an arc dispersant, dispersing the concentrated arc energy over a larger area and reducing local energy density. Simultaneously, the high melting point of alumina ensures its stability at high arc temperatures, inhibiting the melting and splashing of the metal matrix, thereby significantly improving the material's resistance to arc erosion.

[0018] Fourth, the ultrasonic-assisted ball milling process achieves uniform dispersion of the three-phase reinforcing phase. In traditional ball milling, nanoparticles tend to agglomerate due to their high specific surface energy. This invention introduces ultrasonic assistance, utilizing the localized high-temperature, high-pressure micro-regions generated by ultrasonic cavitation to effectively break up nanoparticle agglomerates and promote uniform dispersion of the reinforcing phase in the copper matrix. The mechanical vibration of ultrasound also promotes the entry of nanoparticles into the gaps between copper powder particles and surface depressions, increasing the contact area between the reinforcing phase and the matrix.

[0019] Fifth, spark plasma sintering (SPS) has significant advantages over traditional hot pressing sintering. SPS uses pulsed current to directly heat powder particles, with a heating rate of 100-1000℃ / min, resulting in short sintering time and low energy consumption. The rapid sintering process effectively inhibits grain growth and maintains the dimensional stability of the nano-reinforcing phase; simultaneously, the plasma discharge effect generated by the pulsed current cleans oxides and adsorbed impurities from the powder particle surface, promoting metallurgical bonding between particles. The electric field in the SPS process also facilitates the directional alignment of the conductive graphene phase, forming a connected conductive network.

[0020] Sixth, hot extrusion molding further densifies the composite material and optimizes its microstructure. The intense plastic deformation during hot extrusion can eliminate residual porosity in the SPS preform, achieving high densification close to the theoretical density. Simultaneously, the dynamic recrystallization caused by plastic deformation can refine the copper matrix grains, improving material strength. The streamlined deformation during extrusion also allows the layered graphene to align along the extrusion direction, facilitating the formation of continuous conductive channels and further enhancing the material's conductivity.

[0021] In the preparation method of the highly conductive copper-based nanocomposite contact material of the present invention, the process parameters of each step are further optimized as follows:

[0022] In step one, the copper powder preferably has a particle size of 5-50 μm and a purity greater than 99.9%. Too small a particle size results in an excessively large specific surface area, making it prone to oxidation; too large a particle size hinders subsequent sintering and densification. The solution containing silver ions is prepared by dissolving silver nitrate in deionized water, with a silver ion concentration preferably of 0.01-0.1 mol / L. Too low a silver ion concentration leads to discontinuous nano-silver coating layers; too high a concentration increases silver consumption, raising costs and potentially forming excessively thick silver layers that affect subsequent processing. The graphene oxide concentration is preferably 0.5-2 mg / mL, with a sheet thickness of 1-5 layers and a lateral dimension of 1-20 μm. Few-layer graphene has a higher specific surface area and better conductivity, and a moderate lateral dimension facilitates uniform dispersion in the matrix and the construction of a conductive network.

[0023] In step one, the reducing agent is preferably one or a combination of ascorbic acid, hydrazine hydrate, or sodium borohydride. Ascorbic acid, as a green reducing agent, has a mild and controllable reduction rate, which is beneficial for obtaining a uniform nano-silver coating layer and high-quality reduced graphene oxide; hydrazine hydrate has strong reducing power and can be used in combination with ascorbic acid; sodium borohydride has a fast reduction rate and is suitable for low-temperature conditions. The preferred temperature for the chemical co-reduction reaction is 60-90℃, and the preferred reaction time is 1-4 h. Too low a temperature will lead to incomplete reduction reaction and residual silver ions; too high a temperature may lead to oxidation of copper powder. The reaction process is carried out under inert gas protection with magnetic stirring, and the preferred stirring rate is 200-500 r / min to ensure uniform mixing of reactants and prevent oxidation of copper powder.

[0024] In step one, after the chemical co-reduction reaction is completed, the silver-coated copper / reduced graphene oxide composite powder is preferably obtained by filtration, washing, and vacuum drying. The thickness of the nano-silver coating layer is preferably 50-200 nm; a silver layer that is too thin will not provide an effective interfacial transition, while a layer that is too thick will consume excessive silver resources. The mass fraction of reduced graphene oxide is preferably 0.1-1.0 wt%; a graphene content that is too low will not form an effective conductive network, while a content that is too high will lead to agglomeration and interfacial problems. The mass fraction of silver is preferably 0.5-3.0 wt%.

[0025] In step two, the particle size of the nano-alumina powder is preferably 20-100 nm, and the addition amount is preferably 0.3-2.0 wt% of the total mass of the composite powder. Nano-alumina has a larger specific surface area and better dispersibility, but if the particle size is too small, it is easy to agglomerate; if the addition amount is too small, the anti-arc erosion effect is not obvious, while if the addition amount is too large, it will significantly reduce the conductivity.

[0026] In step two, the preferred conditions for ultrasonic-assisted ball milling are: ultrasonic power 300-600 W, ultrasonic frequency 20-40 kHz, ball milling speed 150-300 r / min, ball-to-material ratio 5:1-10:1, and ball milling time 2-6 h. Anhydrous ethanol is preferred as the milling medium, as it prevents copper powder oxidation and promotes the dispersion of the reinforcing phase. Too low an ultrasonic power results in poor dispersion, while too high a power may damage the graphene structure. Too high a ball milling speed introduces excessive mechanical energy, leading to lattice defects, while too low a speed results in uneven mixing.

[0027] In step three, the preferred conditions for spark plasma sintering are: sintering temperature 700-850℃, sintering pressure 30-60MPa, heating rate 80-150℃ / min, holding time 5-15 min, and vacuum degree less than 10 Pa. The sintering temperature needs to be higher than the recrystallization temperature of copper to promote densification, but excessively high temperatures should be avoided to prevent excessive grain growth; rapid heating can inhibit grain growth and maintain the nanostructure; the vacuum environment prevents the oxidation of copper and graphene.

[0028] In step four, the preferred conditions for hot extrusion molding are: extrusion temperature 600-750℃, extrusion ratio 10:1-25:1, extrusion speed 1-5 mm / s, and preheating time of the preform before extrusion 15-30 min. If the extrusion temperature is too low, the material will lack plasticity and is prone to cracking; if it is too high, grain growth will be significant. The extrusion ratio determines the degree of deformation; if the extrusion ratio is too small, densification will be insufficient, while if it is too large, the extrusion pressure will be too high and may damage the die.

[0029] Following step four, an annealing process is preferably included: annealing is performed in a mixed atmosphere of hydrogen and argon at a temperature of 300-450℃ for 1-3 hours, with a hydrogen volume fraction of 10-25% in the mixed atmosphere. Annealing can eliminate processing stress introduced by hot extrusion, promote dislocation rearrangement and recrystallization, and improve the plasticity and fatigue resistance of the material; the reducing atmosphere can prevent oxidation of the material surface.

[0030] A second aspect of this invention provides a highly conductive copper-based nanocomposite contact material prepared by the above-described method. The composite material comprises a copper matrix and nano-silver phase, reduced graphene oxide phase, and nano-alumina phase dispersed within the copper matrix. The nano-silver phase forms a gradient transition interface layer between the copper matrix and the reduced graphene oxide phase. This interface structure effectively solves the problems of poor wettability and weak interfacial bonding between graphene and the copper matrix.

[0031] The highly conductive copper-based nanocomposite contact material of this invention exhibits excellent comprehensive properties. Its room temperature conductivity reaches 10³-10⁷ IACS, higher than pure copper; its conductivity at 150℃ reaches 72-78% IACS, demonstrating excellent high-temperature conductivity. The material's tensile strength reaches 350-420 MPa, and its microhardness reaches 120-160 HV, significantly higher than pure copper. In arc erosion tests, the material's arc erosion rate is significantly lower than that of pure copper and conventional copper alloys, exhibiting excellent resistance to arc erosion.

[0032] A third aspect of this invention provides the application of the aforementioned highly conductive copper-based nanocomposite contact material as an anti-arc erosion contact material in power fitting splice clamps or connectors. The composite material of this invention is particularly suitable for power fitting components in power systems, such as splice clamps, tension clamps, and connectors, which need to withstand high currents and frequent switching. It can significantly improve the service life and reliability of power fittings and reduce the operation and maintenance costs of power systems.

[0033] Compared with the prior art, the present invention has at least the following beneficial effects:

[0034] First, this invention employs a chemical co-reduction method to simultaneously prepare a nano-silver coating layer and reduced graphene oxide. This process is simple, low-cost, and easily scalable. Compared to high-cost processes such as chemical vapor deposition, the preparation method of this invention requires less equipment, consumes less energy, and yields higher output, making it more suitable for industrial applications.

[0035] Secondly, this invention creatively constructs a gradient interface structure of nano-silver-graphene-copper, effectively solving the key technical challenges of poor wettability and weak interfacial bonding between graphene and the copper substrate. The nano-silver layer, acting as an interfacial transition layer, forms a good metallurgical bond with the copper substrate on the one hand, and exhibits good wettability and electronic doping effects on graphene on the other, achieving synergistic optimization of interfacial bonding strength and conductivity.

[0036] Third, this invention achieves comprehensive optimization of electrical conductivity, mechanical properties, and arc erosion resistance through the synergistic reinforcement of three phases: nano-silver, reduced graphene oxide, and nano-alumina. Nano-silver improves electrical conductivity and oxidation resistance; reduced graphene oxide forms a conductive network and reduces the temperature coefficient of resistance; and nano-alumina provides resistance to arc erosion. The synergistic effect of the three reinforcing phases makes the overall performance of the composite material far superior to that of composite materials with a single reinforcing phase.

[0037] Fourth, this invention employs a process route combining spark plasma sintering (SPS) and hot extrusion molding, achieving synergistic control of high density and nanostructure. Rapid SPS sintering effectively maintains the dimensional stability of the nano-reinforcing phase, while hot extrusion further densifies and optimizes the distribution and orientation of the reinforcing phase, resulting in a final material with excellent microstructure uniformity and performance stability.

[0038] Fifth, the high-conductivity copper-based nanocomposite contact material of the present invention has excellent conductivity with a room temperature conductivity of 103-107% IACS and a 150℃ conductivity of 72-78% IACS, as well as excellent mechanical properties with a tensile strength of 350-420 MPa and a microhardness of 120-160 HV. It is particularly suitable for high-requirement applications such as power fittings, connectors, and splice clamps, and can significantly improve the safety and reliability of power systems. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the preparation process of the highly conductive copper-based nanocomposite contact material of the present invention;

[0040] Figure 2 The image shows the SEM morphology of the three-phase composite powder.

[0041] Figure 3 This is a comparison graph of the conductivity of the examples and comparative examples;

[0042] Figure 4 The diagram shows a comparison of the arc ablation performance of the examples and comparative examples.

[0043] Figure 5 A comparison diagram of the mechanical properties of the embodiments and comparative examples;

[0044] Figure 6This is a SEM-EDS elemental surface scan image of the Cu-Ag-rGO-Al2O3 composite material of the present invention;

[0045] Figure 7 This is a bright-field TEM image of the nano-silver coating layer and the reduced graphene oxide sheet of the present invention.

[0046] Figure 8 This is a high-resolution HRTEM image and FFT diffraction pattern of the Cu-Ag interface of the present invention. Detailed Implementation

[0047] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The main raw materials and their specifications used in the embodiments of this invention are as follows:

[0049] Copper powder: particle size 5-50 μm, purity ≥99.9%, oxygen content <0.1%.

[0050] Silver nitrate: analytical grade, purity ≥99.8%.

[0051] Graphene oxide dispersion: concentration 2 mg / mL, sheet thickness 1-5 layers, lateral size 1-20 μm, prepared by modified Hummers method or commercially available.

[0052] Nano-alumina powder: particle size 20-100 nm, α phase, purity ≥99.9%.

[0053] Ascorbic acid: analytical grade, purity ≥99.0%.

[0054] Hydrazine hydrate: analytical grade, concentration 80%.

[0055] Anhydrous ethanol: analytical grade, purity ≥99.5%.

[0056] Argon: purity ≥ 99.999%.

[0057] Hydrogen: purity ≥ 99.99%.

[0058] Example 1

[0059] like Figure 1 As shown, the preparation of a highly conductive copper-based nanocomposite contact material with a nano-silver content of 1.5 wt%, a reduced graphene oxide content of 0.5 wt%, and a nano-alumina content of 0.8 wt% specifically includes the following steps:

[0060] Step 1: Preparation of silver-coated copper / reduced graphene oxide composite powder by chemical co-reduction:

[0061] Weigh 100 g of copper powder with a particle size of 10-30 μm, and ultrasonically disperse it in 500 mL of deionized water. The ultrasonic power is 400 W and the ultrasonic time is 15 min to obtain a copper powder suspension.

[0062] Preparation of silver ion solution: Weigh 2.36 g of silver nitrate and dissolve it in 200 mL of deionized water to obtain a silver nitrate solution with a concentration of approximately 0.07 mol / L.

[0063] Preparation of graphene oxide dispersion: Take 250 mL of graphene oxide stock solution with a concentration of 2 mg / mL and dilute it with 250 mL of deionized water to a concentration of 1 mg / mL.

[0064] The silver ion solution and graphene oxide dispersion were slowly added sequentially to the copper powder suspension, and the mixture was magnetically stirred for 30 minutes to ensure homogeneity. The mixture was then transferred to a three-necked flask equipped with a reflux condenser, and high-purity argon gas was introduced for protection. The temperature was then raised to 75°C.

[0065] Weigh 15 g of ascorbic acid and dissolve it in 100 mL of deionized water. Slowly add the solution dropwise to the mixture over a period of about 30 min. After the addition is complete, continue to stir the mixture magnetically at 75 °C for 2.5 h at a stirring rate of 350 r / min.

[0066] After the reaction was complete, the heating was turned off and the mixture was allowed to cool naturally to room temperature. The solid product was separated by vacuum filtration, washed three times each with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 60°C for 8 hours to obtain approximately 101.8 g of silver-coated copper / reduced graphene oxide composite powder.

[0067] Scanning electron microscopy (SEM) was used to observe the morphology of the composite powder. A uniform layer of silver nanoparticles with a thickness of approximately 80-120 nm was observed on the surface of the copper powder, and reduced graphene oxide sheets were attached to the silver-coated copper powder surface. Energy dispersive spectroscopy (EDS) analysis confirmed that the silver content was approximately 1.48 wt% and the carbon content was approximately 0.51 wt% (corresponding to reduced graphene oxide).

[0068] Step 2: Ultrasonic-assisted ball milling mixing:

[0069] Weigh 100 g of the silver-coated copper / reduced graphene oxide composite powder obtained in step one, add 0.8 g of nano-alumina powder (particle size 50 nm), and place it in a stainless steel ball mill jar. Add 500 mL of anhydrous ethanol as the ball milling medium, with a ball-to-material ratio of 8:1. The ball milling balls are stainless steel balls with diameters of 5 mm and 10 mm mixed in a 1:1 mass ratio.

[0070] The ball milling jar was placed in an ultrasonic-assisted ball mill, and the ultrasonic power was set to 450 W, the ultrasonic frequency to 25 kHz, and the ball milling speed to 200 r / min. Ultrasonic-assisted ball milling was performed for 4 hours. During the ball milling process, the machine was stopped for 15 minutes every hour to cool down and prevent overheating.

[0071] After ball milling, the slurry was removed and dried in a vacuum drying oven at 60℃ for 6 h to obtain a three-phase composite powder. The particle size distribution of the composite powder was determined using a laser particle size analyzer. It is approximately 15 μm in size and is relatively evenly distributed.

[0072] Step 3: Spark Plasma Sintering

[0073] The three-phase composite powder obtained in step two was loaded into a graphite mold with an inner diameter of 30 mm. The inner wall of the mold was pre-lined with graphite paper for easy demolding. The mold containing the powder was then placed in a spark plasma sintering furnace, and the sintering parameters were set as follows:

[0074] First, evacuate the furnace chamber to below 5 Pa, then heat it to 780°C at a heating rate of 100°C / min, while applying pressure to 45 MPa. Hold the temperature at 780°C and 45 MPa for 10 min, then turn off the heating power and allow the furnace to cool to below 200°C before depressurizing and removing the sample.

[0075] The resulting composite billet was a cylinder with a diameter of 30 mm and a height of approximately 15 mm. Its surface had a metallic luster and no obvious cracks or defects. The density of the billet, determined using Archimedes' displacement method, was 8.75 g / cm³. Its relative density is approximately 98.5%.

[0076] Step 4: Hot extrusion molding:

[0077] The composite preform obtained in step three is preheated in a tubular resistance furnace at a preheating temperature of 680℃ for 20 minutes, with argon gas introduced for protection during the preheating process.

[0078] After preheating, the billet is quickly transferred to the extrusion cylinder of a hot extrusion press, which is preheated to 650°C. Hot extrusion is performed using a conical extrusion die with an extrusion ratio of 16:1 and an extrusion speed of 2 mm / s.

[0079] A cylindrical composite material with a diameter of approximately 7.5 mm and a length of approximately 240 mm was obtained. The extruded sample was then air-cooled to room temperature.

[0080] Step 5: Annealing treatment:

[0081] The composite rods obtained in step four were placed in a tube-type resistance furnace for annealing. A mixture of hydrogen and argon was introduced into the furnace, with hydrogen comprising 15% and a gas flow rate of 100 mL / min.

[0082] The temperature was increased to 380°C at a heating rate of 5°C / min, held at that temperature for 2 hours, and then cooled to room temperature in the furnace to obtain the highly conductive copper-based nanocomposite contact material of this embodiment.

[0083] The following performance tests were performed on the composite material prepared in Example 1:

[0084] Conductivity test: The resistivity of the material was measured using the four-probe method, and the conductivity was calculated. The conductivity at room temperature (25℃) was 104.8% IACS; the conductivity at high temperature (150℃) was 74.2% IACS.

[0085] Mechanical property testing: The tensile strength was determined using a universal testing machine, and the tensile strength was 386 MPa with an elongation of 12.3%. The Vickers hardness was determined using a microhardness tester (load 200 g, holding time 15 s), and the microhardness was 138 HV.

[0086] Density test: The density was determined using Archimedes' displacement method, and was 8.82 g / cm³. Its relative density is approximately 99.2%.

[0087] like Figure 2 As shown, the microstructure of the composite material was observed using a scanning electron microscope. The copper matrix has fine and uniform grains, with an average grain size of approximately 5-10 μm. Nanoscale silver and nanoscale alumina phases are dispersed in the matrix and at grain boundaries, without obvious agglomeration. The reduced graphene oxide sheets are oriented along the extrusion direction, forming a continuous conductive network.

[0088] Arc ablation test: Arc ablation was performed using an electrical contact tester. Test conditions: DC voltage 24 V, current 15 A, switching frequency 1 Hz, number of cycles 5000. Test results: The average arc energy of the material was 2.85 kJ, the average arc duration was 28.5 ms, and the mass loss was 0.82 mg.

[0089] Example 2

[0090] The preparation of a highly conductive copper-based nanocomposite contact material with a nano-silver content of 2.0 wt%, a reduced graphene oxide content of 0.3 wt%, and a nano-alumina content of 1.2 wt% specifically includes the following steps:

[0091] Step 1: Preparation of silver-coated copper / reduced graphene oxide composite powder by chemical co-reduction

[0092] Weigh 100 g of copper powder with a particle size of 20-40 μm, and ultrasonically disperse it in 600 mL of deionized water. The ultrasonic power is 450 W and the ultrasonic time is 20 min to obtain a copper powder suspension.

[0093] Preparation of silver ion solution: Weigh 3.15 g of silver nitrate and dissolve it in 250 mL of deionized water to obtain a silver nitrate solution with a concentration of approximately 0.075 mol / L.

[0094] Preparation of graphene oxide dispersion: Take 150 mL of graphene oxide stock solution with a concentration of 2 mg / mL and dilute it with 150 mL of deionized water to a concentration of 1 mg / mL.

[0095] The silver ion solution and graphene oxide dispersion were slowly added sequentially to the copper powder suspension, and the mixture was magnetically stirred for 40 minutes to ensure homogeneity. The mixture was then transferred to a three-necked flask equipped with a reflux condenser, and high-purity argon gas was introduced for protection. The temperature was then raised to 80°C.

[0096] Weigh 12 g of ascorbic acid and 2 mL of hydrazine hydrate and dissolve them in 120 mL of deionized water. Slowly add the solution dropwise to the mixture over a period of about 40 min. After the addition is complete, continue to stir the mixture magnetically at 80 °C for 3 h at a stirring rate of 400 r / min.

[0097] After the reaction was complete, the heating was turned off and the mixture was allowed to cool naturally to room temperature. The solid product was separated by vacuum filtration, washed three times each with deionized water and anhydrous ethanol, and then dried in a vacuum drying oven at 55°C for 10 h to obtain approximately 102.2 g of silver-coated copper / reduced graphene oxide composite powder.

[0098] Step 2: Ultrasonic-assisted ball milling mixing

[0099] Weigh 100 g of the silver-coated copper / reduced graphene oxide composite powder obtained in step one, add 1.2 g of nano-alumina powder (particle size 30 nm), and place it in a stainless steel ball mill jar. Add 600 mL of anhydrous ethanol as the milling medium, with a ball-to-particle ratio of 10:1.

[0100] Place the ball milling jar in an ultrasonic-assisted ball mill, set the ultrasonic power to 500 W, the ultrasonic frequency to 30 kHz, and the ball milling speed to 250 r / min, and perform ultrasonic-assisted ball milling for 5 h.

[0101] After ball milling, the slurry was removed and dried in a vacuum drying oven at 55°C for 8 hours to obtain a three-phase composite powder.

[0102] Step 3: Spark Plasma Sintering

[0103] The three-phase composite powder was loaded into a graphite mold with an inner diameter of 30 mm, and the sintering parameters were set as follows: vacuum to 3 Pa, heating rate 120℃ / min, sintering temperature 800℃, sintering pressure 50 MPa, and holding time 8 min.

[0104] The density of the composite green body obtained was 8.79 g / cm³. Its relative density is approximately 98.9%.

[0105] Step 4: Hot extrusion molding

[0106] The preheating temperature of the billet is 700℃, and the preheating time is 25 min. The extrusion ratio is 20:1, the extrusion speed is 3 mm / s, and the extrusion barrel temperature is 670℃.

[0107] A cylindrical composite material with a diameter of approximately 6.7 mm was obtained.

[0108] Step 5: Annealing

[0109] The highly conductive copper-based nanocomposite contact material of this embodiment was obtained by annealing at 400℃ for 1.5 h and with a hydrogen gas integral of 20%.

[0110] Room temperature conductivity: 105.6% IACS; High temperature (150℃) conductivity: 75.1% IACS.

[0111] Tensile strength: 398 MPa; elongation: 11.2%; microhardness: 145 HV.

[0112] Density: 8.85 g / cm³ Its relative density is approximately 99.5%.

[0113] Arc ablation test (same conditions as in Example 1): average arc energy 2.68 kJ, average arc duration 26.8 ms, mass loss 0.71 mg.

[0114] Example 3

[0115] The preparation of a highly conductive copper-based nanocomposite contact material with a nano-silver content of 0.8 wt%, a reduced graphene oxide content of 0.8 wt%, and a nano-alumina content of 0.5 wt% specifically includes the following steps:

[0116] Step 1: Preparation of silver-coated copper / reduced graphene oxide composite powder by chemical co-reduction

[0117] Weigh 100 g of copper powder with a particle size of 5-20 μm, and ultrasonically disperse it in 450 mL of deionized water. The ultrasonic power is 350 W and the ultrasonic time is 12 min.

[0118] Preparation of silver ion solution: Weigh 1.26 g of silver nitrate and dissolve it in 150 mL of deionized water to obtain a silver nitrate solution with a concentration of approximately 0.05 mol / L.

[0119] Preparation of graphene oxide dispersion: Take 400 mL of graphene oxide stock solution with a concentration of 2 mg / mL and dilute it with 400 mL of deionized water to a concentration of 1 mg / mL.

[0120] Silver ion solution and graphene oxide dispersion were added sequentially to copper powder suspension, and the mixture was magnetically stirred for 35 min. Argon gas was introduced for protection, and the temperature was raised to 70℃.

[0121] Weigh 18 g of ascorbic acid and dissolve it in 150 mL of deionized water. Add the solution slowly dropwise. The reaction temperature is 70℃, the reaction time is 2 h, and the stirring rate is 300 r / min.

[0122] After processing, approximately 101.5 g of silver-coated copper / reduced graphene oxide composite powder was obtained.

[0123] Step 2: Ultrasonic-assisted ball milling mixing

[0124] 100 g of composite powder, 0.5 g of nano-alumina (particle size 80 nm), 450 mL of anhydrous ethanol, and a ball-to-particle ratio of 6:1 were used. The ultrasonic power was 350 W, the ultrasonic frequency was 22 kHz, the ball milling speed was 180 r / min, and the ball milling time was 3 h.

[0125] Step 3: Spark Plasma Sintering

[0126] Sintering parameters: vacuum degree 8 Pa, heating rate 90℃ / min, sintering temperature 750℃, sintering pressure 35 MPa, holding time 12 min.

[0127] The relative density of the billet is approximately 98.0%.

[0128] Step 4: Hot extrusion molding

[0129] Preheating temperature: 650℃, preheating time: 18 min. Extrusion ratio: 12:1, extrusion speed: 1.5 mm / s.

[0130] Step 5: Annealing

[0131] Annealing temperature 350℃, holding time 2.5 h, hydrogen gas integral 12%.

[0132] Performance testing

[0133] Room temperature conductivity: 106.2% IACS; High temperature (150℃) conductivity: 76.5% IACS.

[0134] Tensile strength: 368 MPa; elongation: 14.5%; microhardness: 128 HV.

[0135] Density: 8.78 g / cm³ Its relative density is approximately 98.8%.

[0136] Arc ablation test: average arc energy 3.12 kJ, average arc duration 31.2 ms, mass loss 0.95 mg.

[0137] Example 4

[0138] The preparation of a highly conductive copper-based nanocomposite contact material with a nano-silver content of 2.5 wt%, a reduced graphene oxide content of 0.6 wt%, and a nano-alumina content of 1.5 wt% specifically includes the following steps:

[0139] Step 1: Preparation of silver-coated copper / reduced graphene oxide composite powder by chemical co-reduction

[0140] Weigh 100 g of copper powder with a particle size of 15-35 μm, and ultrasonically disperse it in 550 mL of deionized water. The ultrasonic power is 420 W and the ultrasonic time is 18 min.

[0141] Preparation of silver ion solution: Weigh 3.94 g of silver nitrate and dissolve it in 280 mL of deionized water to obtain a silver nitrate solution with a concentration of approximately 0.085 mol / L.

[0142] Preparation of graphene oxide dispersion: Take 300 mL of graphene oxide stock solution with a concentration of 2 mg / mL and dilute it with 300 mL of deionized water to a concentration of 1 mg / mL.

[0143] Silver ion solution and graphene oxide dispersion were added sequentially to copper powder suspension, and the mixture was magnetically stirred for 45 min. Argon gas was introduced for protection, and the temperature was raised to 85℃.

[0144] Weigh 14 g of ascorbic acid and 3 mL of hydrazine hydrate and dissolve them in 130 mL of deionized water. Add the solution slowly dropwise. The reaction temperature is 85℃, the reaction time is 3.5 h, and the stirring rate is 420 r / min.

[0145] After processing, approximately 103.0 g of silver-coated copper / reduced graphene oxide composite powder was obtained.

[0146] Step 2: Ultrasonic-assisted ball milling mixing

[0147] 100 g of composite powder, 1.5 g of nano-alumina (particle size 40 nm), 550 mL of anhydrous ethanol, and a ball-to-particle ratio of 9:1 were used. The ultrasonic power was 550 W, the ultrasonic frequency was 35 kHz, the ball milling speed was 280 r / min, and the ball milling time was 5.5 h.

[0148] Step 3: Spark Plasma Sintering

[0149] Sintering parameters: vacuum degree 4 Pa, heating rate 130℃ / min, sintering temperature 820℃, sintering pressure 55 MPa, holding time 7 min.

[0150] The relative density of the billet is approximately 99.1%.

[0151] Step 4: Hot extrusion molding

[0152] Preheating temperature: 720℃, preheating time: 28 min. Extrusion ratio: 22:1, extrusion speed: 4 mm / s, extrusion barrel temperature: 700℃.

[0153] Step 5: Annealing

[0154] Annealing temperature 420℃, holding time 1.5 h, hydrogen gas integral 22%.

[0155] Room temperature conductivity: 103.5% IACS; High temperature (150℃) conductivity: 73.0% IACS.

[0156] Tensile strength: 415 MPa; elongation: 9.8%; microhardness: 156 HV.

[0157] Density: 8.86 g / cm³ Its relative density is approximately 99.6%.

[0158] Arc ablation test: average arc energy 2.52 kJ, average arc duration 25.1 ms, mass loss 0.62 mg.

[0159] Example 5

[0160] A highly conductive copper-based nanocomposite contact material with a nano-silver content of 1.2 wt%, a reduced graphene oxide content of 0.4 wt%, and a nano-alumina content of 1.0 wt% was prepared.

[0161] The specific parameters for steps one through five are as follows:

[0162] The reaction mixture consisted of copper powder with a particle size of 10-25 μm, silver nitrate 1.89 g (0.06 mol / L), graphene oxide 200 mL (concentration 1 mg / mL), ascorbic acid 12 g, and reacted at 72℃ for 2.5 h.

[0163] 1.0 g of nano-alumina (particle size 60 nm), ultrasonic power 400 W, ball milling speed 220 r / min, ball milling time 4 h.

[0164] SPS parameters: sintering temperature 770℃, pressure 42 MPa, heating rate 110℃ / min, holding time 9 min.

[0165] Hot extrusion: Preheating temperature 670℃, extrusion ratio 15:1, extrusion speed 2.5 mm / s.

[0166] Annealing: 360℃, 2 h, 18% hydrogen.

[0167] Room temperature conductivity: 105.1% IACS; High temperature (150℃) conductivity: 74.8% IACS.

[0168] Tensile strength: 392 MPa; elongation: 11.8%; microhardness: 142 HV.

[0169] Arc ablation test: average arc energy 2.75 kJ, average arc duration 27.5 ms, mass loss 0.78 mg.

[0170] Comparative Example 1

[0171] The preparation of pure copper material for comparison specifically includes the following steps:

[0172] 100 g of copper powder with a particle size of 10-30 μm was weighed and directly subjected to spark plasma sintering. Sintering parameters: vacuum degree 5 Pa, heating rate 100℃ / min, sintering temperature 780℃, sintering pressure 45 MPa, holding time 10 min.

[0173] Hot extrusion: Preheating temperature 680℃, extrusion ratio 16:1, extrusion speed 2 mm / s.

[0174] Annealing: 380℃, 2 h, hydrogen 15%.

[0175] Room temperature conductivity: 100.2% IACS; High temperature (150℃) conductivity: 69.5% IACS.

[0176] Tensile strength: 228 MPa; elongation: 32.5%; microhardness: 68 HV.

[0177] Arc ablation test: average arc energy 4.52 kJ, average arc duration 45.2 ms, mass loss 1.85 mg.

[0178] Comparative Example 2

[0179] As a comparison, a copper-based composite material containing only reduced graphene oxide (0.5 wt%) was prepared, without nano-silver and nano-alumina.

[0180] Graphene oxide was dispersed in copper powder using ultrasonic dispersion, and then ascorbic acid was added to reduce the graphene oxide. The subsequent sintering and molding process was the same as in Example 1.

[0181] Room temperature conductivity: 101.5% IACS; High temperature (150℃) conductivity: 70.8% IACS.

[0182] Tensile strength: 305 MPa; elongation: 15.8%; microhardness: 102 HV.

[0183] Arc ablation test: average arc energy 3.85 kJ, average arc duration 38.5 ms, mass loss 1.42 mg.

[0184] Comparative Example 3

[0185] As a comparison, a copper-based composite material containing only nano-silver (1.5 wt%) was prepared, without reduced graphene oxide and nano-alumina.

[0186] A nano-silver coating layer was deposited on the surface of copper powder using a chemical reduction method, and the subsequent sintering and forming process was the same as in Example 1.

[0187] Room temperature conductivity: 102.8% IACS; High temperature (150℃) conductivity: 71.5% IACS.

[0188] Tensile strength: 268 MPa; elongation: 22.5%; microhardness: 85 HV.

[0189] Arc ablation test: average arc energy 4.15 kJ, average arc duration 41.5 ms, mass loss 1.65 mg.

[0190] Comparative Example 4

[0191] A copper-based composite material containing reduced graphene oxide (0.5 wt%) and nano-alumina (0.8 wt%) but without nano-silver was prepared as a comparison.

[0192] The graphene oxide dispersion was directly mixed with copper powder, and after reduction with ascorbic acid, it was mixed with nano-alumina by ball milling. The subsequent sintering and molding process was the same as in Example 1.

[0193] Room temperature conductivity: 100.8% IACS; High temperature (150℃) conductivity: 70.2% IACS.

[0194] Tensile strength: 328 MPa; elongation: 13.2%; microhardness: 115 HV.

[0195] Arc ablation test: average arc energy 3.25 kJ, average arc duration 32.5 ms, mass loss 1.12 mg.

[0196] Table 1 summarizes the performance test results of the examples and comparative examples.

[0197] sample Room temperature conductivity (%IACS) Conductivity at 150℃ (%IACS) Tensile strength (MPa) Microhardness (HV) Arc energy (kJ) Mass loss (mg) Example 1 104.8 74.2 386 138 2.85 0.82 Example 2 105.6 75.1 398 145 2.68 0.71 Example 3 106.2 76.5 368 128 3.12 0.95 Example 4 103.5 73.0 415 156 2.52 0.62 Example 5 105.1 74.8 392 142 2.75 0.78 Comparative Example 1 100.2 69.5 228 68 4.52 1.85 Comparative Example 2 101.5 70.8 305 102 3.85 1.42 Comparative Example 3 102.8 71.5 268 85 4.15 1.65 Comparative Example 4 100.8 70.2 328 115 3.25 1.12

[0198] Combination Figure 3-5 As can be seen from Table 1:

[0199] First, regarding conductivity. The room temperature conductivity of Examples 1-5 all reached 103-107% IACS, higher than the 100.2% IACS of pure copper. This is attributed to the high conductivity of nano-silver, the conductive network formed by reduced graphene oxide, and the electronic doping effect of nano-silver at the interface. Example 3 exhibited the highest conductivity (106.2% IACS) because it had a higher content of reduced graphene oxide and a lower content of nano-alumina, forming a more complete conductive network. Regarding high-temperature (150°C) conductivity, the conductivity decay of the examples was significantly less than that of pure copper, which is related to the low temperature coefficient of resistance of graphene.

[0200] Comparative Example 2, containing only reduced graphene oxide and no silver nanoparticles, exhibited a room-temperature conductivity of only 101.5% IACS, significantly lower than that of the Example. This indicates that the silver nanoparticle layer not only provides conductive channels but, more importantly, improves the interfacial bonding between graphene and the copper substrate, promoting efficient electron transport at the interface. Although Comparative Example 4 contained both reduced graphene oxide and alumina nanoparticles, the lack of a gradient interface formed by silver nanoparticles resulted in poor interfacial bonding between graphene and the copper substrate, leading to a conductivity even lower than that of Comparative Example 2.

[0201] Second, regarding mechanical properties, the tensile strength of all examples reached 368-415 MPa, and the microhardness reached 128-156 HV, far exceeding that of pure copper (228 MPa, 68 HV). This is attributed to the synergistic strengthening effect of the three-phase reinforcing phases: the dispersion strengthening effect of nano-silver and nano-alumina particles, the load transfer strengthening effect of reduced graphene oxide, and the grain refinement effect brought about by SPS and hot extrusion processes. Example 4 exhibited the highest mechanical properties because it had the highest total content of reinforcing phases (approximately 4.6 wt%).

[0202] Although Comparative Examples 2 and 4 also added reinforcing phases, the improvement in mechanical properties was less than that of the examples. This indicates that the nano-silver layer not only improves interfacial conductivity but also significantly enhances the interfacial bonding strength between the reinforcing phase and the matrix, thereby improving load transfer efficiency.

[0203] Third, regarding resistance to arc ablation. The arc energy of all examples was below 3.2 kJ, the arc duration was below 32 ms, and the mass loss was below 1.0 mg, significantly better than pure copper (4.52 kJ, 45.2 ms, 1.85 mg). This is attributed to the arc dispersion effect and high-temperature stability of nano-alumina. Example 4 exhibited the best resistance to arc ablation (arc energy 2.52 kJ, mass loss 0.62 mg) because it had the highest nano-alumina content (1.5 wt%).

[0204] Comparative Example 3, containing only nano-silver and no nano-alumina, exhibited arc erosion resistance (4.15 kJ, 1.65 mg) close to that of pure copper, indicating that adding nano-silver alone has limited improvement on arc erosion resistance. Comparative Example 4, containing nano-alumina but no nano-silver, showed better arc erosion resistance (3.25 kJ, 1.12 mg) than Comparative Example 3, but not as good as the Example 1. This may be because the lack of nano-silver leads to interfacial problems, making the material more susceptible to interlayer delamination under arcing.

[0205] The formation mechanism of the excellent properties of the highly conductive copper-based nanocomposite contact material of this invention can be analyzed from the following aspects:

[0206] From a molecular and atomic level perspective, the in-situ deposition of nano-silver on the surface of copper powder follows a heterogeneous nucleation mechanism. Under the action of a reducing agent, silver ions first form silver atom clusters at active sites (grain boundaries, defects, etc.) on the copper powder surface, and then grow through diffusion to form a continuous nano-silver coating layer. Both silver and copper have face-centered cubic crystal structures with lattice constants of 0.4086 nm and 0.3615 nm, respectively, and a lattice mismatch of approximately 13%, forming a semi-coherent relationship at the interface, reducing the interfacial energy and providing an effective electron transport channel. Simultaneously, silver atoms can electron-dopantize adjacent reduced graphene oxide, increasing the carrier concentration of graphene and thus enhancing conductivity. Figure 8 As shown, the high-resolution transmission electron microscopy (HRTEM) image of the Cu-Ag interface clearly shows the lattice fringes of Cu and Ag. The Cu region shows a (111) interplanar spacing of 0.209 nm, and the Ag region shows a (111) interplanar spacing of 0.236 nm. Periodic misfit dislocations can be observed at the interface, appearing about once every 7-8 atomic planes, confirming the semi-coherent interface relationship formed between Cu and Ag. The fast Fourier transform (FFT) diffraction pattern in the inset shows that the diffraction spots of Cu and Ag are arranged along the same zone axis

[110] , further verifying the orientation relationship between the two phases.

[0207] From a microstructural perspective, the three-phase reinforcing phases form a specific spatial distribution within the copper matrix. The nano-silver layer is mainly distributed on the surface and grain boundaries of the copper grains, forming continuous, highly conductive channels. Reduced graphene oxide sheets are anchored to the copper matrix through the silver layer, oriented along the extrusion direction, forming a conductive network parallel to the extrusion direction. Nano-alumina particles are dispersed throughout the matrix and grain boundaries, serving as dispersion reinforcement and hindering dislocation movement. This multi-scale, multi-phase composite microstructure is the structural basis for the material's excellent overall performance. Figure 6 As shown, the SEM-EDS elemental surface scan images of the composite material visually demonstrate the spatial distribution characteristics of each phase: Cu elements constitute the matrix phase, Ag elements are enriched at grain boundaries and grain surfaces to form interconnected conductive channels, the superimposed distribution of Al and C elements shows that nano-alumina particles are dispersed in the matrix, and the reduced graphene oxide sheets are oriented along the extrusion direction. Figure 7 As shown, the bright-field image of transmission electron microscopy (TEM) clearly shows that the nano-silver coating layer (thickness 50-200 nm) uniformly covers the surface of copper grains, and the reduced graphene oxide nanosheets are anchored on the copper substrate through the silver layer, presenting a few-layer structure (3-8 layers). A gradient transition interface structure is formed between the Cu substrate, the Ag intermediate layer, and the rGO sheets.

[0208] From the perspective of the macroscopic performance formation mechanism, the improvement in conductivity stems from the superposition of multiple conductivity mechanisms: the metallic conductivity of the silver coating layer, the high-mobility electron conduction of graphene, and the electron doping enhancement effect at the silver-graphene interface. According to the mixing law of composite material conductivity, the final conductivity is the weighted sum of the conductivity contributions of each phase. Since the conductivity of nano-silver and graphene is higher than that of copper, and they form a connected conductive network, the conductivity of the composite material is higher than that of pure copper. The improvement in mechanical properties stems from the combined effects of dispersion strengthening, grain refinement strengthening, and load transfer strengthening, which can be quantitatively described using the Orowan model and the Hall-Petch relationship. The improvement in arc ablation resistance is due to the arc dispersion effect and high-temperature phase stability of nano-alumina, which disperses arc energy, reduces local temperature rise, and decreases metal spatter.

[0209] There is a synergistic effect among the various technical features. Nano-silver not only provides conductive channels but also improves the graphene-copper interface, allowing the excellent properties of graphene to be effectively utilized. Nano-alumina, while providing resistance to arc erosion, also enhances the mechanical properties of the material through its dispersed distribution. The high thermal conductivity of graphene facilitates rapid heat conduction, reducing localized heat accumulation during arcing. The synergistic effect of the three reinforcing phases enables the composite material to achieve comprehensive optimization of its electrical conductivity, mechanical properties, and arc erosion resistance.

[0210] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made based on the technical solutions of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for producing a high-conductivity copper-based nanocomposite contact material, characterized by, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

2. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 1, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

3. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 1 or 2, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

4. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 3, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

5. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 4, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

6. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 5, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

7. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 6, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof.

8. The method for preparing the highly conductive copper-based nanocomposite contact material according to claim 7, characterized in that, The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. The application relates to a high-conductivity copper-based nanocomposite contact material and a preparation method thereof. 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10. Use of the high-conductivity copper-based nanocomposite contact material according to claim 9 as an anti-arc-ablation contact material in a power hardware jointing clamp or connector.

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