A copper-based composite material with high strength and plasticity and conductivity, and a preparation method and application thereof

Abstract

The application provides a high-strength plastic and conductive copper-based composite material and a preparation method and application thereof, and belongs to the technical field of copper-based metal composite materials.The high-strength plastic and conductive copper-based composite material provided by the application comprises a copper matrix and silver modified MXene uniformly dispersed in the copper matrix; the silver modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer gap of the layered MXene nanosheets; and the mass of the silver modified MXene is 0.1-0.8% of the mass of the high-strength plastic and conductive copper-based composite material.The high-strength plastic and conductive copper-based composite material provided by the application can avoid the problems of easy agglomeration and poor interface in the process of compounding two-dimensional carbon material MXene nanosheets with metal copper, and can make the composite material have high strength, plasticity and conductivity.

Description

Technical Field

[0001] This invention relates to the field of copper-based metal composite materials technology, and in particular to a high-strength, high-plasticity, and high-conductivity copper-based composite material, its preparation method, and its applications. Background Technology

[0002] Among conductive metals, copper is an industrial metal with conductivity second only to silver and a lower price, making it widely used in electrical contact materials, electronic packaging, and integrated circuits. However, with societal progress and development, the inherent strength and ductility of copper are increasingly failing to meet the growing demands of industrial and environmental applications. While elemental doping can improve the strength and ductility of copper through solid solution strengthening and precipitation strengthening, unfortunately, this also introduces defects that hinder electron transport, thus affecting conductivity. Similarly, introducing high-strength ceramic reinforcing phases, due to their even lower conductivity than copper, inevitably leads to a decrease in conductivity while increasing the strength of copper.

[0003] Two-dimensional carbon materials (such as graphene and MXene) possess unique two-dimensional geometry, high intrinsic strength, and high modulus, effectively confining dislocation movement while also exhibiting excellent electrical conductivity. Therefore, using two-dimensional carbon materials as reinforcing phases holds promise for overcoming the current limitations in the strength, plasticity, and conductivity of copper-based composites. However, the strong van der Waals forces, high specific surface area, and low metal wettability of two-dimensional carbon materials easily lead to agglomeration and poor intermetallic compatibility, thus affecting the overall performance of copper-based composites and limiting their practical applications. Therefore, there is an urgent need to provide a copper-based composite material with high strength, plasticity, and electrical conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, high-plasticity, and high-conductivity copper-based composite material, its preparation method, and its applications. The high-strength, high-plasticity, and high-conductivity copper-based composite material provided by this invention exhibits high strength and plasticity as well as excellent conductivity.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a high-strength, ductile, and conductive copper-based composite material, comprising a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix;

[0007] The silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer gaps of the layered MXene nanosheets;

[0008] The mass of the silver-modified MXene is 0.1 to 0.8% of the mass of the high-strength, ductile, and conductive copper-based composite material.

[0009] Preferably, the mass of the silver nanoparticles is 20-50% of the mass of the silver-modified MXene.

[0010] Preferably, the silver nanoparticles have a particle size ≤150nm.

[0011] Preferably, the chemical formula of the layered MXene nanosheets is Ti₂C₃T. x The chemical formula contains T x Including one or more of -OH, -O and -F.

[0012] Preferably, the layered MXene nanosheets have ≤10 layers.

[0013] This invention also provides a method for preparing the high-strength, ductile, and conductive copper-based composite material described in the above technical solution, comprising the following steps:

[0014] (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension;

[0015] (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor;

[0016] (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, high-plasticity, and high-conductivity copper-based composite material.

[0017] Preferably, the temperature of the reduction reaction in step (1) is room temperature, and the time of the reduction reaction is 10 to 20 minutes.

[0018] Preferably, the sintering in step (3) is vacuum hot pressing sintering.

[0019] Preferably, the sintering holding temperature in step (3) is 900-1000℃, and the sintering holding time is 60-90min.

[0020] The present invention also provides the application of the high-strength, ductile, and conductive copper-based composite material described in the above technical solution or the high-strength, ductile, and conductive copper-based composite material prepared by the preparation method described in the above technical solution in electrical contact materials, electronic packaging, or integrated circuits.

[0021] The present invention provides a high-strength, high-ductility, and high-conductivity copper-based composite material, comprising a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets; the mass of the silver-modified MXene is 0.1-0.8% of the mass of the high-strength, high-ductility, and high-conductivity copper-based composite material. The present invention uses silver-modified MXene as a reinforcement, with silver nanoparticles uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets. The silver nanoparticles in the interlayer spaces can prevent the aggregation and stacking of the two-dimensional MXene nanosheets, increasing their specific surface area and dispersibility in the copper matrix; furthermore, the silver nanoparticles on the surface of the silver-modified MXene can increase the wettability of the layered MXene nanosheets with the copper matrix, improve the MXene / copper interface compatibility, and achieve interface reinforcement, thereby giving the composite material high strength, ductility, and conductivity.

[0022] The results of the embodiments show that the high-strength, ductile, and conductive copper-based composite material provided by the present invention has a tensile strength and elongation at break of 342 MPa and 53%, respectively, which are much higher than those of pure copper (tensile strength and elongation at break of 249 MPa and 30%, respectively) and MXene / copper-based composite material (tensile strength and elongation at break of 195 MPa and 36%, respectively). Meanwhile, the high-strength, ductile, and conductive copper-based composite material provided by the present invention has a strength-ductility product of approximately 18 GPa% and a conductivity as high as 95.0% IACS, while the conductivity of pure copper is 92.4% IACS and that of the MXene / copper-based composite material is only 90.7% IACS. Furthermore, the MXene at the fracture surface of the MXene / copper composite material is clustered, indicating that the unmodified MXene nanosheets agglomerate and stack in the copper matrix, while the MXene at the fracture surface of the high-strength, ductile, and conductive copper-based composite material provided by the present invention is uniformly distributed in a sheet-like manner, proving that silver effectively prevents the agglomeration and stacking of MXene. Therefore, the high-strength, ductile, and conductive copper-based composite material provided by this invention solves the problems of easy agglomeration and poor interfacial properties in the process of combining existing two-dimensional carbon materials with metallic copper, and obtains high strength, ductility, and conductivity. Attached Figure Description

[0023] Figure 1 These are scanning electron microscope (SEM) images of the MXene nanosheets used in Examples 1-3 and Comparative Example 2 of this invention.

[0024] Figure 2 This is a scanning electron microscope image of the silver-modified MXene prepared in step (1) of Example 1 of the present invention;

[0025] Figure 3These are scanning electron microscope (SEM) images of the dendritic copper powder used in Examples 1-3 and Comparative Examples 1-2 of the present invention.

[0026] Figure 4 A scanning electron microscope image of the high-strength, ductile, and conductive copper-based composite material provided in Embodiment 1 of the present invention;

[0027] Figure 5 This is a comparison diagram of the stress-strain curves of sample 1 in Example 1 of the present invention and samples 1-2 in Comparative Examples;

[0028] Figure 6 This is a comparison chart of the comprehensive performance of the sample in Example 1 of the present invention and the samples in Comparative Examples 1 and 2 in terms of strong plasticity and conductivity.

[0029] Figure 7 This is a scanning electron microscope image of the tensile fracture surface of the sample in Comparative Example 2 of this invention.

[0030] Figure 8 This is a scanning electron microscope image of the tensile fracture surface of the sample in Example 1 of the present invention. Detailed Implementation

[0031] This invention provides a high-strength, high-plasticity, and high-conductivity copper-based composite material, comprising a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer gaps of the layered MXene nanosheets; the mass of the silver-modified MXene is 0.1% to 0.8% of the mass of the high-strength, high-plasticity, and high-conductivity copper-based composite material.

[0032] The high-strength, ductile, and conductive copper-based composite material provided by this invention includes a copper matrix.

[0033] The high-strength, high-ductility, and high-conductivity copper-based composite material provided by this invention includes silver-modified MXene. This invention utilizes silver-modified MXene as a reinforcement, ensuring its uniform distribution within the copper matrix. This improves the interfacial compatibility between the copper matrix and the layered MXene nanosheets, thereby enhancing the conductivity and strength of the copper matrix.

[0034] In this invention, the mass of the silver-modified MXene is 0.1-0.8% of the mass of the high-strength, ductile, and conductive copper-based composite material, preferably 0.3-0.7%, and more preferably 0.5-0.7%. By controlling the mass of the silver-modified MXene within the above range, this invention is more beneficial for improving the conductivity and strength / ductility of the copper-based composite material.

[0035] In this invention, the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets. The silver nanoparticles are uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets. This invention utilizes the silver nanoparticles on the surface of the layered MXene nanosheets to improve the interfacial compatibility between the layered MXene nanosheets and the copper matrix, and utilizes the silver nanoparticles in the interlayer spaces to prevent the aggregation and stacking of the two-dimensional MXene nanosheets, thereby increasing the specific surface area of ​​the MXene nanosheets and their dispersion in the copper matrix, thus giving the copper-based composite material high strength, plasticity, and conductivity.

[0036] In this invention, the mass of the silver nanoparticles is preferably 20-50% of the mass of the silver-modified MXene, more preferably 25-45%, and most preferably 35-45%. By controlling the mass of the silver nanoparticles within the above range, this invention is more conducive to the uniform dispersion of silver nanoparticles and improves the dispersibility of layered MXene nanosheets.

[0037] In this invention, the particle size of the silver nanoparticles is preferably ≤150 nm, more preferably 1–100 nm. By controlling the particle size of the silver nanoparticles within the above range, this invention is more conducive to improving the interfacial compatibility between the layered MXene nanosheets and the copper matrix, and allows them to intercalate into the interlayer gaps of the layered MXene nanosheets, thereby improving the dispersibility and specific surface area of ​​the MXene nanosheets and preventing their aggregation and stacking.

[0038] In this invention, the chemical formula of the layered MXene nanosheets is preferably Ti2C3T. x The chemical formula contains T x Preferably, it includes one or more of -OH, -O, and -F. This invention selects layered MXene nanosheets of the above types, which have more functional groups, making them more suitable for modification with silver nanoparticles to prevent aggregation and increase wettability with the copper matrix.

[0039] In this invention, the number of layers in the layered MXene nanosheets is preferably ≤10 layers, more preferably 1 to 5 layers. By controlling the number of layers in the layered MXene nanosheets within the above range, this invention can ensure a high specific surface area and reduce aggregation and stacking problems.

[0040] The high-strength, ductile, and conductive copper-based composite material provided by this invention can avoid the problems of easy agglomeration and poor interfacial properties during the composite process of two-dimensional carbon material MXene nanosheets and metallic copper, and enable the composite material to obtain high strength, ductile, and conductive properties.

[0041] The present invention also provides a method for preparing the high-strength, ductile, and conductive copper-based composite material described in the above technical solution, comprising the following steps:

[0042] (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension;

[0043] (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor;

[0044] (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, high-plasticity, and high-conductivity copper-based composite material.

[0045] This invention involves mixing a silver salt solution and a layered MXene nanosheet dispersion with water to carry out a reduction reaction, thereby obtaining a silver-modified MXene suspension.

[0046] In this invention, the concentration of the silver salt solution is preferably 1–4 mg / mL, more preferably 3–4 mg / mL. By controlling the concentration of the silver salt solution within the above range, this invention ensures that the silver ions are in uniform and sufficient contact with the layered MXene nanosheets, thereby achieving better modification of the layered MXene nanosheets.

[0047] In this invention, the silver salt solution is preferably a silver nitrate solution. By selecting a silver nitrate solution, the good solubility of silver nitrate in water ensures that the formed silver nanoparticles are uniform and dispersed.

[0048] In this invention, the concentration of the layered MXene nanosheet dispersion is preferably 1–4 mg / mL, more preferably 3–4 mg / mL. By controlling the concentration of the layered MXene nanosheet dispersion within the above range, this invention facilitates sufficient contact with silver ions and utilizes the functional groups on its surface to achieve a reduction reaction of silver ions, resulting in silver nanoparticles that are firmly and uniformly bound to its surface and the interlayer gaps.

[0049] In this invention, the solvent for the layered MXene nanosheet dispersion is preferably deionized water.

[0050] The present invention does not have any special requirements for the dispersion method of the layered MXene nanosheet dispersion; any dispersion preparation method well known in the art can be used.

[0051] In this invention, the water is preferably distilled water.

[0052] In this invention, the volume ratio of the silver salt solution, the layered MXene nanosheet dispersion and water is (20-60):(20-60):(30-50), more preferably (28-40):(26-40):(30-40).

[0053] In this invention, the preferred method for mixing the silver salt solution and the layered MXene nanosheet dispersion with water is to simultaneously add the silver salt solution and the layered MXene nanosheet dispersion dropwise into water while stirring. In this invention, a reduction reaction occurs during the mixing process of the silver salt solution and the layered MXene nanosheet dispersion with water. This invention, by employing the above mixing method, facilitates more thorough mixing of the silver salt solution and the MXene nanosheet dispersion.

[0054] In this invention, the temperature of the reduction reaction is preferably room temperature, and the time of the reduction reaction is preferably 10-20 min, more preferably 10-15 min. By controlling the temperature and time of the reduction reaction within the above ranges, this invention is more conducive to the full reduction of silver ions into silver nanoparticles and their uniform distribution on the surface and in the interlayer gaps of MXene nanosheets.

[0055] After obtaining the silver-modified MXene suspension, the present invention mixes the silver-modified MXene suspension with a copper dispersion and then performs filtration and drying sequentially to obtain the composite material precursor.

[0056] In this invention, the concentration of the copper dispersion is preferably 100–600 mg / mL, more preferably 150–550 mg / mL. By controlling the concentration of the copper dispersion within the above range, this invention facilitates sufficient contact between copper and silver-modified MXene and ensures uniform distribution of silver-modified MXene within the copper matrix.

[0057] In this invention, the copper in the copper dispersion is preferably dendritic copper powder; the particle size of the dendritic copper powder is preferably 10-15 μm. By using the above-mentioned type of copper and controlling its particle size within the above range, this invention ensures that the copper matrix formed after sintering still has a fine particle size and uniform structure, which is more conducive to obtaining higher conductivity and strong plasticity.

[0058] In this invention, the solvent for the copper dispersion is preferably ethanol.

[0059] In this invention, the volume ratio of the silver-modified MXene suspension to the copper dispersion is preferably (70-170):(100-600), more preferably (94-120):(200-300).

[0060] In this invention, the preferred method for mixing the silver-modified MXene suspension and the copper dispersion is to add the silver-modified MXene suspension dropwise to the copper dispersion while stirring. By employing this mixing method, this invention facilitates more uniform mixing of the silver-modified MXene suspension and the copper dispersion, thereby improving the dispersibility of silver-modified MXene in the copper matrix.

[0061] In this invention, the mixing temperature is preferably room temperature, and the mixing time is preferably 1 to 3 hours, more preferably 2 hours. By controlling the mixing temperature and time within the above ranges, this invention facilitates the uniform mixing of the silver-modified MXene suspension and the copper dispersion.

[0062] In this invention, the filtration is preferably performed under vacuum. The filtration frequency is preferably 2-5 mL per cycle. This invention does not have specific requirements regarding the number of filtration cycles, as long as it ensures the complete removal of unreacted silver nitrate and residual ethanol from the mixture.

[0063] In this invention, the drying is preferably vacuum drying. The drying temperature is preferably 30–40°C, more preferably 35°C; the drying time is preferably 24–30 hours, more preferably 24 hours. By drying and controlling the temperature and time within the above ranges, this invention can effectively remove moisture from the composite material precursor and prevent the oxidation of silver therein.

[0064] After obtaining the composite material precursor, the present invention sintersulates the composite material precursor to obtain a high-strength, ductile, and conductive copper-based composite material.

[0065] In this invention, the sintering is preferably vacuum hot pressing sintering. By employing vacuum hot pressing sintering, this invention can avoid oxidation of silver nanoparticles and copper; simultaneously, during the sintering process, the silver on the surface of the silver-modified MXene can be dissolved in the copper matrix, resulting in a good metallurgical bonding interface between MXene and the copper matrix; furthermore, it ensures that the microstructure of the sintered composite material is more compact, which is more conducive to improving the conductivity and plasticity of the composite material.

[0066] In this invention, the sintering holding temperature is preferably 900–1000℃, more preferably 920–980℃; the sintering holding time is preferably 60–90 min, more preferably 60–80 min. By controlling the sintering holding temperature and holding time within the above ranges, this invention facilitates the full wetting of the copper matrix and MXene nanosheets, improves interfacial compatibility, and ensures that the sintered composite material has a denser microstructure and finer grains, which is more conducive to improving the conductivity and plasticity of the composite material.

[0067] In this invention, the heating rate of the sintering is preferably 8-10°C / min, more preferably 9-10°C / min. The cooling method of the sintering is preferably: cooling to 200°C at a rate of 10-15°C / min, followed by furnace cooling to room temperature. By controlling the heating rate within the above range and selecting the above cooling method, this invention ensures uniform heating of the material and avoids the residual heat during cooling affecting the microstructure of the composite material, thereby improving the electrical conductivity and plasticity of the composite material.

[0068] The high-strength, ductile, and conductive copper-based composite material prepared by the method provided by this invention has a high specific surface area and is uniformly dispersed in the copper matrix, which enables the composite material to obtain high strength, ductile, and conductive properties. At the same time, the preparation method is simple, the parameters are easy to control, the raw materials are readily available, and the cost is low.

[0069] The present invention also provides the application of the high-strength, ductile, and conductive copper-based composite material described in the above technical solution or the high-strength, ductile, and conductive copper-based composite material prepared by the preparation method described in the above technical solution in electrical contact materials, electronic packaging, or integrated circuits.

[0070] The application of the high-strength, ductile, and conductive copper-based composite material provided by this invention in electrical contact materials, electronic packaging, and integrated circuits can leverage the better conductivity and high ductility of the high-strength, ductile, and conductive copper-based composite material to make it have a wider range of application prospects.

[0071] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0072] Example 1

[0073] A high-strength, high-ductility, and high-conductivity copper-based composite material is composed of a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; wherein the mass of the silver-modified MXene is 0.5% of the mass of the high-strength, high-ductility, and high-conductivity copper-based composite material; the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets; the mass of the silver nanoparticles is 40.8% of the mass of the silver-modified MXene; the particle size of the silver nanoparticles is 20–100 nm; and the chemical formula of the layered MXene nanosheets is Ti₂C₃T. x The chemical formula contains T x The molecule is -OH, -O, or -F; the number of layers in the layered MXene nanosheets is between 1 and 5.

[0074] The preparation method of the high-strength, ductile, and conductive copper-based composite material comprises the following steps:

[0075] (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension. Specifically, 30 mL of a layered MXene dispersion with a concentration of 3.5 mg / mL and 30 mL of a silver salt solution (silver nitrate solution) with a concentration of 3.8 mg / mL were respectively added dropwise to 40 mL of distilled aqueous solution with stirring and the reduction reaction was carried out at room temperature for 10 min to obtain a silver-modified MXene suspension. The volume ratio of the silver salt solution, the layered MXene nanosheet dispersion and water was 30:30:40.

[0076] (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor. Specifically, 35g (particle size 10-15μm) of dendritic copper powder is weighed and added to 200mL of ethanol solution with stirring to prepare a copper dispersion with a concentration of 175mg / mL. Then, the silver-modified MXene suspension obtained in step (1) is added dropwise to the copper dispersion with stirring and stirred at room temperature for 2h. Then, it is transferred to a vacuum filtration device for vacuum filtration using a dropper. The filtration frequency is 3mL / time. After the 3mL of silver-modified MXene suspension is filtered, another 3mL is transferred to the vacuum filtration device for filtration. This cycle is repeated until all the silver-modified MXene suspension is filtered. Finally, it is transferred to a vacuum drying oven and dried at 35℃ for 24h. The volume ratio of the silver-modified MXene suspension to the copper dispersion is 100:200.

[0077] (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, plastic and conductive copper-based composite material; specifically: vacuum hot pressing sintering is performed using a graphite mold with a diameter of 30 mm. The sintering parameters are: heating to 950 °C at 10 °C / min and holding for 60 min, then cooling to 200 °C at 12.5 °C / min, and finally cooling to room temperature with the furnace to obtain a high-strength, plastic and conductive copper-based composite material, denoted as Cu / Ag@MXene.

[0078] Example 2

[0079] A high-strength, high-ductility, and high-conductivity copper-based composite material is composed of a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; wherein the mass of the silver-modified MXene is 0.5% of the mass of the high-strength, high-ductility, and high-conductivity copper-based composite material; the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets; the mass of the silver nanoparticles is 40.6% of the mass of the silver-modified MXene; the particle size of the silver nanoparticles is 20–120 nm; and the chemical formula of the layered MXene nanosheets is Ti₂C₃T.x The chemical formula contains T x The molecule is -OH, -O, or -F; the number of layers in the layered MXene nanosheets is between 1 and 5.

[0080] The preparation method of the high-strength, ductile, and conductive copper-based composite material comprises the following steps:

[0081] (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension. Specifically, 26 mL of a layered MXene dispersion with a concentration of 4 mg / mL and 28 mL of a silver salt solution (silver nitrate solution) with a concentration of 4 mg / mL were taken and added dropwise to 40 mL of distilled aqueous solution with stirring. The reduction reaction was carried out at room temperature for 10 min to obtain a silver-modified MXene suspension. The volume ratio of the silver salt solution, the layered MXene nanosheet dispersion and water was 26:28:40.

[0082] (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the precursor of the composite material. Specifically, 35g (particle size 10-15μm) of dendritic copper powder is weighed and added to 200mL of ethanol solution with stirring to prepare a copper dispersion with a concentration of 175mg / mL. Then, the silver-modified MXene suspension obtained in step (1) is added dropwise to the copper dispersion with stirring and stirred at room temperature for 2h. Then, it is transferred to a vacuum filtration device for vacuum filtration using a dropper. The filtration frequency is 3mL / time. After the 3mL of silver-modified MXene suspension is filtered, another 3mL is transferred to the vacuum filtration device for filtration. This cycle is repeated until all the silver-modified MXene suspension is filtered. Finally, it is transferred to a vacuum drying oven and dried at 35℃ for 24h. The volume ratio of the silver-modified MXene suspension to the copper dispersion is 94:200.

[0083] (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, plastic and conductive copper-based composite material; specifically: vacuum hot pressing sintering is performed using a graphite mold with a diameter of 30 mm. The sintering parameters are: heating to 950 °C at 10 °C / min and holding for 60 min, then cooling to 200 °C at 12.5 °C / min, and finally cooling to room temperature with the furnace to obtain a high-strength, plastic and conductive copper-based composite material, denoted as Cu / Ag@MXene.

[0084] Example 3

[0085] A high-strength, high-ductility, and high-conductivity copper-based composite material is composed of a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; wherein the mass of the silver-modified MXene is 0.7% of the mass of the high-strength, high-ductility, and high-conductivity copper-based composite material; the silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer spaces of the layered MXene nanosheets; the mass of the silver nanoparticles is 40.8% of the mass of the silver-modified MXene; the particle size of the silver nanoparticles is 50–140 nm; and the chemical formula of the layered MXene nanosheets is Ti₂C₃T. x The chemical formula contains T x The molecule is -OH, -O, or -F; the number of layers in the layered MXene nanosheets is between 1 and 5.

[0086] The preparation method of the high-strength, ductile, and conductive copper-based composite material comprises the following steps:

[0087] (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension. Specifically, 40 mL of a 3.5 mg / mL MXene dispersion and 40 mL of a 3.8 mg / mL silver salt solution (silver nitrate solution) were taken and added dropwise to 40 mL of a distilled aqueous solution with stirring. The reduction reaction was carried out at room temperature for 10 min to obtain a silver-modified MXene suspension. The volume ratio of the silver salt solution, the layered MXene nanosheet dispersion and water was 40:40:40.

[0088] (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor. Specifically, 35g (particle size 10-15μm) of dendritic copper powder is weighed and added to 200mL of ethanol solution with stirring to prepare a copper dispersion with a concentration of 175mg / mL. Then, the silver-modified MXene suspension obtained in step (1) is added dropwise to the copper dispersion with stirring and stirred at room temperature for 2h. Then, it is transferred to a vacuum filtration device for vacuum filtration using a dropper. The filtration frequency is 3mL / time. After the 3mL of silver-modified MXene suspension is filtered, another 3mL is transferred to the vacuum filtration device for filtration. This cycle is repeated until all the silver-modified MXene suspension is filtered. Finally, it is transferred to a vacuum drying oven and dried at 35℃ for 24h. The volume ratio of the silver-modified MXene suspension to the copper dispersion is 120:200.

[0089] (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, plastic and conductive copper-based composite material; specifically: vacuum hot pressing sintering is performed using a graphite mold with a diameter of 30 mm. The sintering parameters are: heating to 950 °C at 10 °C / min and holding for 60 min, then cooling to 200 °C at 12.5 °C / min, and finally cooling to room temperature with the furnace to obtain a high-strength, plastic and conductive copper-based composite material, denoted as Cu / Ag@MXene.

[0090] Comparative Example 1

[0091] Weigh 35 mg of dendritic copper powder and slowly add it to 200 mL of ethanol while stirring to prepare a copper dispersion. Then, perform vacuum filtration at a frequency of 3 mL / time. After each 3 mL of copper dispersion is filtered, transfer another 3 mL to the filtration apparatus for filtration. Repeat this process until all copper dispersions are filtered. Finally, transfer the dispersion to a vacuum drying oven and dry at 35 °C for 24 h. Then, perform sintering. Specifically, use a graphite mold with a diameter of 30 mm for vacuum hot pressing sintering. The sintering parameters are: heat up to 950 °C at 10 °C / min and hold for 60 min, then cool down to 200 °C at 12.5 °C / min, and finally cool to room temperature with the furnace to obtain pure copper, denoted as Cu.

[0092] Comparative Example 2

[0093] Weigh 35 mg of dendritic copper powder and slowly add it to 150 mL of ethanol while stirring to prepare a copper dispersion. Keep the mixture at room temperature and stir for later use. Take 30 mL of layered MXene nanosheet dispersion with a concentration of 3.5 mg / mL and add it dropwise to the copper dispersion while stirring. Stir at room temperature for 2 hours to obtain a mixture. Then, use a dropper to transfer the mixture to a vacuum filtration device for vacuum filtration. The filtration frequency is 3 mL / time. After the 3 mL mixture is filtered, transfer another 3 mL to the vacuum filtration device for filtration. Repeat this cycle until all the mixtures are filtered. After filtration, transfer the filtered product to a vacuum drying oven and dry at 35 °C for 24 hours. Use a graphite mold with a diameter of 30 mm for hot pressing and sintering. The sintering parameters are: heat up to 950 °C at 10 °C / min and hold for 60 min, then cool down to 200 °C at 12.5 °C / min, and finally cool to room temperature with the furnace to obtain a layered MXene nanosheet reinforced copper-based composite material, denoted as Cu / MXene.

[0094] The layered MXene nanosheets used in Examples 1-3 and Comparative Example 2 of this invention originated from the same source. The microstructure of the layered MXene nanosheets used in Examples 1-3 and Comparative Example 2 was observed using scanning electron microscopy (SEM), and the obtained SEM images are shown below. Figure 1 As shown.

[0095] Depend on Figure 1 It can be seen that MXene nanosheets have a flexible nanosheet morphology, which can provide a large growth area for silver nanoparticles.

[0096] The microstructure of the silver-modified MXene prepared in step (1) of Example 1 of this invention was observed using scanning electron microscopy. The obtained scanning electron microscopy image is shown below. Figure 2 As shown.

[0097] Depend on Figure 2 It can be seen that a large number of silver nanoparticles with a particle size ≤100nm are uniformly grown on the layered MXene nanosheets. The silver nanoparticles can effectively prevent the aggregation and stacking of the layered MXene nanosheets and improve the interface structure of the layered MXene nanosheets.

[0098] The dendritic copper powder used in Examples 1-3 and Comparative Examples 1-2 of this invention originated from the same source. The microstructure of the dendritic copper powder used in Examples 1-3 and Comparative Examples 1-2 was observed using scanning electron microscopy (SEM), and the obtained SEM images are shown below. Figure 3 As shown.

[0099] Depend on Figure 3 It can be seen that the copper powder used has a dendritic copper morphology with a particle size of 10-15 μm.

[0100] The microstructure of the high-strength, ductile, and conductive copper-based composite material provided in Example 1 of this invention was observed using scanning electron microscopy (SEM). The obtained SEM images are shown below. Figure 4 As shown.

[0101] Depend on Figure 4 It can be seen that the silver-modified MXene is uniformly distributed inside the sintered copper matrix without agglomeration or stacking, and has good interfacial bonding, exhibiting a good composite state.

[0102] Tensile properties were tested on the sample of Example 1 and the samples of Comparative Examples 1 and 2 of this invention. The stress-strain curves obtained from the tests are shown in the figure below. Figure 5 As shown.

[0103] Depend on Figure 5As can be seen, the tensile strength and elongation at break of the sample in Example 1 were 342 MPa and 53%, respectively, which were significantly higher than those of pure copper (249 MPa and 30% respectively) and MXene / copper-based composite material (195 MPa and 36% respectively). It is noteworthy that the strength of the unmodified MXene / copper composite material was even lower than that of pure copper. This is due to the poor wettability of MXene and copper, resulting in a poor interface. The significantly improved mechanical properties of the silver-modified MXene / copper composite material are attributed to the effective improvement of the wettability between MXene and copper by the silver nanoparticles, fully leveraging the advantages of MXene's high strength, high toughness, and high conductivity.

[0104] in accordance with Figure 5 The tensile properties shown are calculated based on the strength-ductility product (strength-ductility product = strength × elongation at break) of the sample from Example 2 of this invention and the samples from Comparative Examples 1 and 2. Simultaneously, electrical conductivity tests were performed on the sample from Example 2 of this invention and the samples from Comparative Examples 1 and 2 using a four-probe tester. The comparison results of the strength-ductility and electrical conductivity are as follows: Figure 6 As shown.

[0105] Depend on Figure 6 As can be seen, thanks to the improved interface between MXene and copper, the sample of Example 2 of this invention has high strength and plasticity (strength-plasticity product of about 18 GPa%), as well as high electrical conductivity of up to 95.0% IACS, which is higher than that of pure copper (92.4% IACS) and unmodified MXene / copper-based composite material (90.7% IACS).

[0106] The microstructure of the tensile fracture surfaces of the samples from Comparative Example 2 and Example 1 of this invention was observed using scanning electron microscopy (SEM), and the obtained SEM images are shown below. Figure 7 , Figure 8 As shown.

[0107] Depend on Figure 7 and Figure 8 It can be seen that in Comparative Example 2, the MXene at the fracture surface of the unmodified MXene / copper composite material is distributed in clusters, which is why the performance deteriorates after composite. In contrast, in Example 1, the silver-modified MXene (Ag@MXene) at the fracture surface of the silver-modified MXene / copper composite material is distributed in sheets and uniformly, which proves that silver effectively prevents the aggregation and overlap of MXene, thereby achieving high strength, plasticity and conductivity.

[0108] In summary, the high-strength, ductile, and conductive copper-based composite material provided by this invention solves the problems of easy agglomeration and poor interfacial properties in the process of combining existing two-dimensional carbon materials with metallic copper, and achieves high strength, ductility, and conductivity.

[0109] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-strength, high-plasticity, and high-conductivity copper-based composite material, characterized in that, It consists of a copper matrix and silver-modified MXene uniformly dispersed in the copper matrix; The silver-modified MXene comprises silver nanoparticles and layered MXene nanosheets; the silver nanoparticles are uniformly distributed on the surface and in the interlayer gaps of the layered MXene nanosheets; The mass of the silver-modified MXene is 0.1~0.8% of the mass of the high-strength, ductile, and conductive copper-based composite material; The mass of the silver nanoparticles is 35-50% of the mass of silver-modified MXene; The preparation method of the high-strength, ductile, and conductive copper-based composite material comprises the following steps: (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension; (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor; (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, high-plasticity, and high-conductivity copper-based composite material. The reduction reaction in step (1) is carried out at room temperature for 10-20 minutes. The particle size of the silver nanoparticles is ≤150nm; The chemical formula of the layered MXene nanosheets is Ti2C3T. x The chemical formula contains T x Includes one or more of -OH, -O, and -F; The layered MXene nanosheets have ≤10 layers.

2. The method for preparing the high-strength, ductile, and conductive copper-based composite material as described in claim 1, characterized in that, The steps are as follows: (1) A silver salt solution and a layered MXene nanosheet dispersion were mixed with water to carry out a reduction reaction to obtain a silver-modified MXene suspension; (2) The silver-modified MXene suspension obtained in step (1) is mixed with the copper dispersion and then filtered and dried sequentially to obtain the composite material precursor; (3) The composite material precursor obtained in step (2) is sintered to obtain a high-strength, high-plasticity, and high-conductivity copper-based composite material. The reduction reaction in step (1) is carried out at room temperature for 10-20 minutes.

3. The preparation method according to claim 2, characterized in that, The sintering in step (3) is vacuum hot pressing sintering.

4. The preparation method according to claim 2 or 3, characterized in that, The sintering holding temperature in step (3) is 900~1000℃, and the sintering holding time is 60~90min.

5. The application of the high-strength, ductile, and conductive copper-based composite material as described in claim 1 or the high-strength, ductile, and conductive copper-based composite material prepared by any one of the preparation methods described in claims 2 to 4 in electrical contact materials, electronic packaging, or integrated circuits.

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