Oxygen-free copper microtube and preparation process thereof

Abstract

The invention relates to the technical field of microtubes, in particular to an oxygen-free copper microtube and a preparation process thereof, and the oxygen-free copper microtube comprises the following components: oxygen-free copper, manganese, phosphorus, zinc, nickel, a carbon nanotube, a modified silane coupling agent, aluminum oxide, boron nitride and graphene. According to the oxygen-free copper pipe and the preparation method thereof, various alloy elements and nano reinforced phases are introduced, and an advanced preparation process is adopted, so that various problems existing in a traditional oxygen-free copper pipe are successfully solved. Elements such as manganese, phosphorus, zinc and nickel are added, so that the mechanical property and the thermal stability of the oxygen-free copper are effectively improved; and through introduction of nano materials such as carbon nano tubes, aluminum oxide, boron nitride and graphene, the microstructure and functional characteristics of the oxygen-free copper are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of microtubes, and in particular to an oxygen-free copper microtube and a preparation process thereof. Background Art

[0002] With the continuous advancement of modern science and technology, miniaturization, high precision and high performance have become the goals pursued in the field of materials science. As a metal tube with excellent electrical and thermal conductivity, oxygen-free copper microtubes have broad application prospects in electronics, medical treatment, aerospace and other fields. Especially in occasions that require efficient heat conduction and precise current control, oxygen-free copper microtubes play an irreplaceable role.

[0003] However, traditional oxygen-free copper pipes often have problems such as uneven grain size, insufficient mechanical properties, and poor thermal stability during the preparation process. These problems limit the application of oxygen-free copper pipes in extreme environments such as high temperature and high pressure. In order to improve the comprehensive performance of oxygen-free copper pipes, researchers are constantly exploring new preparation processes and alloying methods.

[0004] Although the existing oxygen-free copper pipe preparation technology has achieved certain results, there are still some shortcomings:

[0005] Grain size control is not precise enough: It is difficult to accurately control the grain size of traditional oxygen-free copper pipes during the preparation process, resulting in unstable material properties.

[0006] Mechanical properties need to be improved: Existing oxygen-free copper pipes still have room for improvement in strength and ductility to meet more demanding application requirements.

[0007] Insufficient thermal stability: In high temperature environments, traditional oxygen-free copper pipes are prone to grain growth and performance degradation, affecting their long-term stability.

[0008] Single function: Most of the existing oxygen-free copper pipes only have basic electrical and thermal conductivity functions and lack the ability of multi-functional integration.

[0009] Therefore, we proposed an oxygen-free copper microtube and its preparation process to solve the above problems. Summary of the invention

[0010] The purpose of the present invention is to solve the shortcomings of the prior art and to propose an oxygen-free copper microtube and a preparation process thereof.

[0011] In order to achieve the above object, the present invention adopts the following technical solutions:

[0012] An oxygen-free copper microtube comprises the following components in parts by weight: 60-80 parts of oxygen-free copper, 1-5 parts of manganese, 0.1-1 parts of phosphorus, 1-5 parts of zinc, 2-10 parts of nickel, 0.5-5 parts of carbon nanotubes, 0.1-1 parts of modified silane coupling agents, 1-5 parts of aluminum oxide, 0.5-5 parts of boron nitride and 0.1-1 parts of graphene.

[0013] As the preferred technical solution:

[0014] The oxygen-free copper microtube as described above comprises the following components in parts by weight: 65 parts of oxygen-free copper, 3 parts of manganese, 0.5 parts of phosphorus, 3 parts of zinc, 7 parts of nickel, 2.5 parts of carbon nanotubes, 0.4 parts of modified silane coupling agent, 2 parts of aluminum oxide, 1.5 parts of boron nitride, and 0.6 parts of graphene.

[0015] The oxygen-free copper microtube as described above, wherein the oxygen-free copper is 4N pure, the grain size is 5-50 microns, and the crystal structure of the oxygen-free copper is a face-centered cubic structure; the median particle size of the manganese is 2-6 microns, the manganese exists in the form of a solid solution or a fine precipitate phase, the size of the precipitate phase is 10-80 nanometers, the shape of the manganese particles is approximately spherical, and the particle ellipticity is less than 1.2, the phosphorus is introduced in the form of copper phosphide or phosphorus alloy, and the phosphorus element is evenly distributed at the grain boundary to reduce the impact on the intracrystalline performance, the zinc is zinc powder with an average particle size of 5-20 microns, and the nickel is evenly dispersed in the oxygen-free copper matrix in the form of fine precipitates. The size of the precipitated phase is 50-200 nanometers; the diameter of the carbon nanotube is 10-50 nanometers, and the average length is 1-10 micrometers; the molecular structure of the modified silane coupling agent has at least one functional group that reacts with the surface of oxygen-free copper and one functional group that is compatible with the organic phase, and the molecular chain length of the modified silane coupling agent is 10-20 carbon atoms; the average particle size of the aluminum oxide is 0.1-1.0 micrometers; the average particle size of the boron nitride is controlled to be 0.5-5.0 micrometers, and the boron nitride has a hexagonal crystal structure; the number of layers of the graphene is 1-5 layers, and the average sheet diameter is 1-10 micrometers.

[0016] The oxygen-free copper microtube as described above has a structural gradient along the length or diameter direction of the microtube, and a gradual change in grain size is induced by heat treatment, and a gradual change structure from nanocrystalline to microcrystalline is formed to enhance the local strength and thermal conductivity of the microtube; manganese is added to the oxygen-free copper in a gradient distribution manner, and the content gradually increases from the inner layer to the outer layer. Through the heat treatment process, manganese is uniformly dispersed in the form of approximately spherical nano-precipitated phases, and these precipitated phases can serve as a reinforcing agent to improve the strength and ductility of the material; the phosphorus is enriched at the oxygen-free copper grain boundary. , forming a stable copper phosphide interface phase; the carbon nanotubes are arranged in a Y-shaped orderly orientation to maximize their mechanical and electrical properties along the Y-shaped direction, and functional groups compatible with the oxygen-free copper matrix are introduced by chemically modifying the surface of the carbon nanotubes; the aluminum oxide has optical properties, including fluorescence or reflection, to introduce additional optical functions to the microtubes; the boron nitride forms a continuous thermal conductive network to improve the overall thermal conductivity of the microtubes; the graphene is uniformly dispersed in the oxygen-free copper matrix in the form of molecular clusters, and these molecular clusters can serve as conductive and thermal conductive channels.

[0017] In the oxygen-free copper microtube as described above, the inorganic-philic group of the modified silane coupling agent can form a strong chemical bond with the surface of the oxygen-free copper. The bonding strength between the modified silane coupling agent and the surface of the oxygen-free copper is set to S, then: S = k_1\cdotA\cdot\exp(-E_a / (R\cdotT));

[0018] Among them, k_1 is the pre-exponential factor, which represents the rate constant of the bonding reaction; A is the reaction surface area, that is, the area where the oxygen-free copper surface contacts the coupling agent; E_a is the activation energy, which represents the energy required for the bonding reaction; R is the gas constant; T is the reaction temperature; the organophilic group can effectively combine with the reinforcing phase of the carbon nanotube to achieve cross-scale interface enhancement. The combination efficiency E of the carbon nanotube and the modified silane coupling agent is: E=k_2\cdotC\cdot\si gma;

[0019] Wherein, k_2 is the binding constant, which indicates the strength of the binding between the carbon nanotube and the modified silane coupling agent; C is the dispersion of the carbon nanotube; \sigma is the surface tension of the carbon nanotube; the modified silane coupling agent forms a primary pre-network and a secondary pre-network inside the microtube to construct a three-dimensional cross-linked structure, and the strength of the three-dimensional cross-linked structure is I: I = S\cdotE\cdotN;

[0020] Among them, S is the bonding strength between the modified silane coupling agent and the oxygen-free copper surface, E is the bonding efficiency between the carbon nanotubes and the modified silane coupling agent, and N is the number of cross-linking points, that is, the number of cross-linking points formed by the coupling agent molecules in the microtubes.

[0021] A second aspect of the present invention provides a process for preparing an oxygen-free copper microtube, comprising the following steps:

[0022] S1: Select high-purity oxygen-free copper as the base material, melt it and cast it into copper ingots;

[0023] S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, and melt them together with oxygen-free copper to form a uniform alloy melt;

[0024] S3: Select high-quality carbon nanotubes, perform acid washing and purification to remove impurities, and introduce active groups on their surfaces to facilitate subsequent interface bonding to obtain pretreated carbon nanotubes;

[0025] S4: dissolving the modified silane coupling agent in an organic solvent to form a uniform solution, then adding the pretreated carbon nanotubes into the organic solvent, and uniformly coating the surface of the carbon nanotubes with a layer of the modified silane coupling agent through stirring and ultrasonic treatment;

[0026] S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using a high-energy ball milling method to make these materials exist in powder form to obtain a processed nano-reinforced phase;

[0027] S6: compounding the alloy melt with the treated nano-reinforced phase by melt infiltration to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix;

[0028] S7: heating the composite material and then performing a stretching process to obtain a stretched oxygen-free copper microtube;

[0029] S8: heat treating the stretched oxygen-free copper microtube to eliminate internal stress;

[0030] S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

[0031] As the preferred technical solution:

[0032] In the above-mentioned process for preparing oxygen-free copper microtubes, in S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

[0033] In the above-mentioned process for preparing oxygen-free copper microtubes, in S3, carbon nanotubes with a diameter of 10-50 nanometers and a length of 1-10 micrometers are selected for pickling and purification. A nitric acid solution with a concentration of 3M is used for pickling. The treatment time is 10-12 hours at a temperature of 60-80°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 12-16 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

[0034] In the process for preparing oxygen-free copper microtubes as described above, in S4, the modified silane coupling agent is selected from the type with a molecular chain length of 10-20 carbon atoms, and the organic solvent is selected from ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and the surface of the carbon nanotubes is uniformly coated with a layer of modified silane coupling agent by stirring and ultrasonic treatment at a stirring speed of 500-1000 rpm and an ultrasonic treatment time of 30-45 minutes.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] 1. A synergistic strengthening effect is formed between the oxygen-free copper matrix and the added alloying elements such as manganese, phosphorus, zinc, and nickel. These elements exist in the form of solid solutions or fine precipitates. Through heat treatment processes, they are evenly dispersed on a microscopic scale, thereby significantly improving the strength and ductility of the material; the addition of nano-reinforcement phases such as carbon nanotubes, alumina, boron nitride, and graphene further enhances this synergistic strengthening effect. These nanomaterials have excellent mechanical properties and thermal conductivity, and their close combination with the oxygen-free copper matrix effectively improves the overall performance of the microtubes.

[0037] 2. Boron nitride and graphene form an efficient thermal conductivity network inside the microtube. Boron nitride has excellent thermal conductivity, and its continuous distribution helps to quickly transfer heat within the microtube. The molecular cluster structure of graphene provides additional thermal conduction channels, further enhancing the thermal conductivity of the microtube. The coordinated construction of this thermal conduction network enables oxygen-free copper microtubes to perform well in application scenarios that require efficient heat conduction, such as electronic equipment heat dissipation, automotive cooling systems, etc.

[0038] 3. By introducing components with specific functions, such as alumina with optical properties, oxygen-free copper microtubes achieve synergy of multifunctionality. This design not only broadens the application range of microtubes, but also meets the demand for multifunctional integration of materials in the field of modern science and technology. The synergy between the components enables these additional functions to be effectively realized without affecting the main performance of the microtubes.

[0039] 4. The use of modified silane coupling agent plays a key role in interface bonding. It significantly enhances the interface bonding force through chemical bonding and effective combination with the oxygen-free copper surface and the nano-enhanced phase, which not only improves the overall performance of the material, but also helps to extend the service life of the microtube, especially in complex and harsh working environments.

[0040] In summary, the present invention demonstrates significant superiority and broad application potential through the synergistic reinforcement among components, the synergistic construction of the thermal conductive network, the synergistic realization of multifunctionality, and the synergistic optimization of interface bonding. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The physical image is measured by the electron microscope of the present invention;

[0042] Figure 2 It is a line graph of the detection data of the present invention. DETAILED DESCRIPTION

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. In the event of a conflict, the definitions in the specification shall prevail. "When mass, concentration, temperature, time, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper preferred values ​​and lower preferred values, this should be understood to specifically disclose all ranges formed by any pairing of any upper range limit or preferred value with any lower range limit or preferred value, regardless of whether the range is disclosed separately. For example, a range of 1-50 should be understood to include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91 6, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50, any number, combination of numbers, or subrange, and all decimal values ​​between the above integers, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. With respect to subranges, "nested subranges" extending from any endpoint within the range are specifically contemplated. For example, nested subranges of the exemplary range 1-50 may include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in the other direction."

[0044] The present invention is further explained below in conjunction with specific examples. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0045] An oxygen-free copper microtube comprises the following components in parts by weight: 60-80 parts of oxygen-free copper, 1-5 parts of manganese, 0.1-1 parts of phosphorus, 1-5 parts of zinc, 2-10 parts of nickel, 0.5-5 parts of carbon nanotubes, 0.1-1 parts of modified silane coupling agents, 1-5 parts of aluminum oxide, 0.5-5 parts of boron nitride and 0.1-1 parts of graphene.

[0046] Specifically, the oxygen-free copper has a purity of 4N, a grain size of 5-50 microns, and a face-centered cubic structure; the median particle size of manganese is 2-6 microns, and manganese exists in the form of a solid solution or a fine precipitate phase, the size of the precipitate phase is 10-80 nanometers, the shape of the manganese particles is approximately spherical, and the particle ellipticity is less than 1.2; phosphorus is introduced in the form of copper phosphide or phosphorus alloy, and the phosphorus element is evenly distributed at the grain boundary to reduce the impact on the intracrystalline performance; zinc uses zinc powder with an average particle size of 5-20 microns; nickel is evenly dispersed in the oxygen-free copper matrix in the form of a fine precipitate phase; The phase size is 50-200 nanometers; the diameter of the carbon nanotubes is 10-50 nanometers, and the average length is 1-10 microns; the molecular structure of the modified silane coupling agent has at least one functional group that reacts with the oxygen-free copper surface and one functional group that is compatible with the organic phase, and the molecular chain length of the modified silane coupling agent is 10-20 carbon atoms; the average particle size of aluminum oxide is 0.1-1.0 microns; the average particle size of boron nitride is controlled at 0.5-5.0 microns, and boron nitride has a hexagonal crystal structure; the number of graphene layers is 1-5, and the average sheet diameter is 1-10 microns.

[0047] Among them, the structural gradient of oxygen-free copper is induced by heat treatment to form a gradually changing grain size along the length or diameter direction of the microtube, and the gradual structure from nanocrystalline to microcrystalline is formed to enhance the local strength and thermal conductivity of the microtube; manganese is added to the oxygen-free copper in a gradient distribution manner, and the content gradually increases from the inner layer to the outer layer. Through the heat treatment process, manganese is evenly dispersed in the form of approximately spherical nano-precipitates. These precipitates can serve as a reinforcing agent to improve the strength and ductility of the material; phosphorus is enriched at the oxygen-free copper grain boundaries to form a stable copper phosphide interface phase; the arrangement of carbon nanotubes is a Y-shaped orderly orientation to maximize its mechanical and electrical properties along the Y-shaped direction, and functional groups compatible with the oxygen-free copper matrix are introduced by chemically modifying the surface of the carbon nanotubes; aluminum oxide has optical properties, including fluorescence or reflection, which introduces additional optical functions to the microtubes; boron nitride forms a continuous thermal conductive network to improve the overall thermal conductivity of the microtubes; graphene is evenly dispersed in the oxygen-free copper matrix in the form of molecular clusters, and these molecular clusters can serve as conductive and thermal conductive channels.

[0048] The following is a specific example, which details how to achieve the various structural and performance characteristics in oxygen-free copper microtubes:

[0049] 1. Structural gradient and grain size gradient

[0050] Preparation process: A multi-step heat treatment process is adopted. First, the oxygen-free copper is annealed at 800°C for 60 minutes, and then the temperature is gradually reduced to 400°C. The temperature is kept warm every time it is reduced by 100°C, and each time the temperature is kept warm for 30 minutes.

[0051] Results: Along the length of the microtubules, a gradual structure from nanocrystals (average grain size of about 50nm) to microcrystals (average grain size of about 5μm) was formed.

[0052] 2. Gradient distribution of manganese and nano-precipitation phase

[0053] Preparation process: During the oxygen-free copper smelting process, manganese is gradually added, and the manganese content gradually increases from 0.1% to 0.5% from the inner layer to the outer layer. Then heat treatment is carried out at 900°C for 120 minutes.

[0054] Results: Manganese was uniformly dispersed in oxygen-free copper in the form of spherical nano-precipitates (average diameter of about 20 nm), and the density of the precipitates increased gradually from the inner layer to the outer layer.

[0055] 3. Formation of copper phosphide interface phase

[0056] Preparation process: In the later stage of oxygen-free copper smelting, 0.05% phosphorus element is added and heat treated at 700°C for 90 minutes.

[0057] Results: Phosphorus was mainly enriched at the grain boundaries of oxygen-free copper, forming a stable copper phosphide interface phase and enhancing the stability of the grain boundaries.

[0058] 4. Y-shaped ordered orientation of carbon nanotubes

[0059] Preparation process: Carbon nanotubes are dispersed in a solvent and functional groups (such as carboxyl) compatible with oxygen-free copper are introduced through chemical modification. Subsequently, under the action of a strong magnetic field, the carbon nanotubes are oriented in a Y-shaped orderly manner and composited with the oxygen-free copper matrix.

[0060] Results: The carbon nanotubes formed a clear Y-shaped arrangement in oxygen-free copper, and the mechanical and electrical properties along the Y-shaped direction were significantly improved.

[0061] 5. Introduction of optical properties of aluminum oxide

[0062] Preparation process: During the oxygen-free copper smelting process, 0.2% of aluminum oxide particles with fluorescent properties (average particle size of about 100 nm) are added.

[0063] Results: Alumina particles were evenly distributed in oxygen-free copper, which introduced obvious fluorescence function to the microtubes and enhanced their optical properties.

[0064] 6. Construction of Boron Nitride Thermal Conductive Network

[0065] Preparation process: Boron nitride nanosheets (average thickness of about 50nm) are mixed evenly with oxygen-free copper powder, and composite microtubes are prepared by hot pressing process.

[0066] Results: Boron nitride nanosheets formed a continuous thermally conductive network in oxygen-free copper, increasing the overall thermal conductivity of the microtubes by about 30%.

[0067] 7. Dispersion of graphene molecular clusters

[0068] Preparation process: Graphene is mixed with oxygen-free copper solution in the form of molecular clusters (average cluster size is about 100nm), evenly dispersed through ultrasonic treatment, and then solidified into shape.

[0069] Results: Graphene molecular clusters are uniformly dispersed in the oxygen-free copper matrix and serve as efficient electrical and thermal conduction channels, significantly improving the electrical and thermal properties of the microtubes.

[0070] Specifically, the inorganic-philic group of the modified silane coupling agent can form a strong chemical bond with the oxygen-free copper surface. The bonding strength between the modified silane coupling agent and the oxygen-free copper surface is set to S, then: S = k_1\cdotA\cdot\exp(-E_a / (R\cdotT))

[0071] Among them, k_1 is the pre-exponential factor, which represents the rate constant of the bonding reaction; A is the reaction surface area, that is, the area where the oxygen-free copper surface contacts the coupling agent; E_a is the activation energy, which represents the energy required for the bonding reaction; R is the gas constant; T is the reaction temperature;

[0072] The organophilic groups can effectively combine with the reinforcing phase of carbon nanotubes to achieve cross-scale interface enhancement. The combination efficiency E of carbon nanotubes and modified silane coupling agents is:

[0073] E=k_2\cdotC\cdot\si gma

[0074] Wherein, k_2 is the binding constant, which indicates the strength of the binding between carbon nanotubes and modified silane coupling agent; C is the dispersion of carbon nanotubes; \sigma is the surface tension of carbon nanotubes;

[0075] The modified silane coupling agent forms a primary pre-network and a secondary pre-network inside the microtube to construct a three-dimensional cross-linked structure, and the strength of the three-dimensional cross-linked structure is I:

[0076] I=S\cdotE\cdotN

[0077] Among them, S is the bonding strength between the modified silane coupling agent and the oxygen-free copper surface, E is the bonding efficiency between the carbon nanotubes and the modified silane coupling agent, and N is the number of cross-linking points, that is, the number of cross-linking points formed by the coupling agent molecules in the microtubes.

[0078] The following is a specific example for illustrating how to combine the modified silane coupling agent with oxygen-free copper and carbon nanotubes in oxygen-free copper microtubes, and calculate related parameters:

[0079] 1. Bonding of modified silane coupling agent and oxygen-free copper

[0080] Calculation of bond strength S: Set reaction conditions: reaction temperature T = 300K, activation energy Ea = 50 kJ / mol, reaction surface area A = 100 m 2 , gas constant R = 8.314 J / (mol·K), pre-exponential factor k1 = 10^10 (representing the order of magnitude of the reaction rate constant).

[0081] According to the formula S = k_1\cdotA\cdot\exp(-E_a / (R\cdotT)), substituting the numerical value into the formula, we can get: S = 10^{10}\cdot100\cdot\exp(-50000 / (8.314\cdot300));

[0082] The specific bonding strength S value is obtained through calculation.

[0083] 2. Combination of modified silane coupling agent and carbon nanotubes

[0084] The calculation of the binding efficiency E sets the following conditions: binding constant k2 = 10^6, dispersion degree of carbon nanotubes C = 0.9 (indicating that 90% of the carbon nanotubes are effectively dispersed), and surface tension of carbon nanotubes σ = 0.05 N / m.

[0085] According to the formula E=k_2\cdotC\cdot\s igma, substituting the numerical value into the calculation, we get: E=10^6\cdot0.9\cdot0.05; the specific binding efficiency E value is obtained through calculation.

[0086] 3. Construction of three-dimensional cross-linked structure

[0087] The calculation of the cross-linking structure strength I is set as follows: the number of cross-linking points N = 1000 (indicating that 1000 cross-linking points are formed in the microtubule). According to the formula I = S\cdotE\cdotN, the previously calculated S and E values ​​are substituted, as well as the N value, and the calculation is performed. The cross-linking structure strength I value is obtained by calculation.

[0088] Embodiment 1

[0089] An oxygen-free copper microtube comprises the following components in parts by weight: 60 parts of oxygen-free copper, 1 part of manganese, 0.1 part of phosphorus, 1 part of zinc, 2 parts of nickel, 0.5 part of carbon nanotube, 0.1 part of modified silane coupling agent, 1 part of aluminum oxide, 0.5 part of boron nitride and 0.1 part of graphene.

[0090] The embodiment also provides a preparation process of an oxygen-free copper microtube, comprising the following steps:

[0091] S1: Select oxygen-free copper with a purity of at least 4N as the base material, melt it and cast it into a copper ingot, the melting temperature is controlled at 1083°C, and after casting into the copper ingot, ensure that its cooling rate is uniform;

[0092] S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, maintain the melt temperature at 1150°C when adding, and melt together with oxygen-free copper for 30 minutes to form a uniform alloy melt;

[0093] S3: Select carbon nanotubes with a diameter of 10 nanometers and a length of 1 micron, and perform acid washing and purification. The acid washing uses a 3M nitric acid solution for 10 hours at a temperature of 60°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 12 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

[0094] S4: The modified silane coupling agent is selected to have a molecular chain length of 10 carbon atoms, and the organic solvent is selected to be ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and a layer of modified silane coupling agent is uniformly coated on the surface of the carbon nanotubes by stirring and ultrasonic treatment at a stirring speed of 500 rpm and an ultrasonic treatment time of 30 minutes;

[0095] S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using high-energy ball milling to make these materials exist in powder form. The high-energy ball milling time is 4 hours and the rotation speed is 300 rpm to obtain a processed nano-reinforced phase;

[0096] S6: compounding the alloy melt and the treated nano-reinforced phase by melt infiltration, wherein the temperature during melt infiltration is controlled at 1200° C. for 10 minutes, and then rapidly cooled to room temperature to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix;

[0097] S7: heating the composite material, and stretching the composite material after heating it to 800° C., with a stretching speed of 1 mm / s and a stretching ratio of 1.5:1, to obtain stretched oxygen-free copper microtubes;

[0098] S8: heat treating the stretched oxygen-free copper microtube at a temperature of 500°C for 1 hour, and then cooling to room temperature at a rate of 10°C / min to eliminate internal stress;

[0099] S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

[0100] Specifically, in S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

[0101] Embodiment 2

[0102] An oxygen-free copper microtube comprises the following components in parts by weight: 65 parts of oxygen-free copper, 2 parts of manganese, 0.3 parts of phosphorus, 2 parts of zinc, 4 parts of nickel, 1.5 parts of carbon nanotubes, 0.4 parts of modified silane coupling agent, 3 parts of aluminum oxide, 2.5 parts of boron nitride and 0.2 parts of graphene.

[0103] The embodiment also provides a preparation process of an oxygen-free copper microtube, comprising the following steps:

[0104] S1: Select oxygen-free copper with a purity of at least 4N as the base material, melt it and cast it into a copper ingot, the melting temperature is controlled at 1113°C, and after casting into the copper ingot, ensure that its cooling rate is uniform;

[0105] S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, maintain the melt temperature at 1180℃ when adding, and melt them together with oxygen-free copper for 40 minutes to form a uniform alloy melt;

[0106] S3: Select carbon nanotubes with a diameter of 20 nanometers and a length of 3 micrometers, and perform acid washing and purification. The acid washing uses a 3M nitric acid solution for 11 hours at a temperature of 65°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 13 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

[0107] S4: The modified silane coupling agent is selected to have a molecular chain length of 15 carbon atoms, and the organic solvent is selected to be ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and stirred and ultrasonically treated at a stirring speed of 700 rpm and an ultrasonic treatment time of 35 minutes to uniformly coat the surface of the carbon nanotubes with a layer of modified silane coupling agent;

[0108] S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using high-energy ball milling to make these materials exist in powder form. The high-energy ball milling time is 5 hours and the rotation speed is 350 rpm to obtain a processed nano-reinforced phase;

[0109] S6: compounding the alloy melt with the treated nano-reinforced phase by melt infiltration, wherein the temperature during melt infiltration is controlled at 1250°C for 12 minutes, and then rapidly cooled to room temperature to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix;

[0110] S7: heating the composite material, and stretching the composite material after heating it to 850° C., with a stretching speed of 1 mm / s and a stretching ratio of 1.5:1, to obtain stretched oxygen-free copper microtubes;

[0111] S8: heat treating the stretched oxygen-free copper microtube at a temperature of 550°C for 1 hour, and then cooling to room temperature at a rate of 10°C / min to eliminate internal stress;

[0112] S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

[0113] Specifically, in S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

[0114] Embodiment 3

[0115] An oxygen-free copper microtube comprises the following components in parts by weight: 70 parts of oxygen-free copper, 3 parts of manganese, 0.7 parts of phosphorus, 4 parts of zinc, 8 parts of nickel, 3 parts of carbon nanotubes, 0.8 parts of modified silane coupling agent, 3 parts of aluminum oxide, 4 parts of boron nitride and 0.7 parts of graphene.

[0116] The embodiment also provides a preparation process of an oxygen-free copper microtube, comprising the following steps:

[0117] S1: Select oxygen-free copper with a purity of at least 4N as the base material, melt it and cast it into a copper ingot. The melting temperature is controlled at 1250°C. After casting into the copper ingot, ensure that its cooling rate is uniform;

[0118] S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, maintain the melt temperature at 1200°C when adding, and melt them together with oxygen-free copper for 50 minutes to form a uniform alloy melt;

[0119] S3: Select carbon nanotubes with a diameter of 30 nanometers and a length of 7 micrometers, and perform acid washing and purification. The acid washing uses a 3M nitric acid solution for 11 hours at a temperature of 70°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 14 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

[0120] S4: The modified silane coupling agent is selected to have a molecular chain length of 18 carbon atoms, and the organic solvent is selected to be ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and stirred and ultrasonically treated at a stirring speed of 800 rpm and an ultrasonic treatment time of 40 minutes to uniformly coat the surface of the carbon nanotubes with a layer of modified silane coupling agent;

[0121] S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using high-energy ball milling to make these materials exist in powder form. The high-energy ball milling time is 5 hours and the rotation speed is 400 rpm to obtain a processed nano-reinforced phase;

[0122] S6: compounding the alloy melt with the treated nano-reinforced phase by melt infiltration, wherein the temperature during melt infiltration is controlled at 1250°C for 13 minutes, and then rapidly cooled to room temperature to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix;

[0123] S7: heating the composite material, and stretching the composite material after heating it to 1000° C., with a stretching speed of 1 mm / s and a stretching ratio of 1.5:1, to obtain stretched oxygen-free copper microtubes;

[0124] S8: heat treating the stretched oxygen-free copper microtube at a temperature of 600°C for 2 hours, and then cooling to room temperature at a rate of 10°C / min to eliminate internal stress;

[0125] S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

[0126] Specifically, in S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

[0127] Embodiment 4

[0128] An oxygen-free copper microtube comprises the following components in parts by weight: 80 parts of oxygen-free copper, 5 parts of manganese, 1 part of phosphorus, 5 parts of zinc, 10 parts of nickel, 5 parts of carbon nanotubes, 1 part of modified silane coupling agent, 5 parts of aluminum oxide, 5 parts of boron nitride and 1 part of graphene.

[0129] The embodiment also provides a preparation process of an oxygen-free copper microtube, comprising the following steps:

[0130] S1: Select oxygen-free copper with a purity of at least 4N as the base material, melt it and cast it into a copper ingot, the melting temperature is controlled at 1300°C, and after casting into the copper ingot, ensure that its cooling rate is uniform;

[0131] S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, maintain the melt temperature at 1250℃ when adding, and melt them together with oxygen-free copper for 60 minutes to form a uniform alloy melt;

[0132] S3: Select carbon nanotubes with a diameter of 50 nanometers and a length of 10 micrometers, and perform acid washing and purification. The acid washing uses a 3M nitric acid solution for 12 hours at a temperature of 80°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 16 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

[0133] S4: The modified silane coupling agent is selected to have a molecular chain length of 20 carbon atoms, and the organic solvent is selected to be ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and stirred and ultrasonically treated at a stirring speed of 1000 rpm and an ultrasonic treatment time of 45 minutes to uniformly coat the surface of the carbon nanotubes with a layer of modified silane coupling agent;

[0134] S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using high-energy ball milling to make these materials exist in powder form. The high-energy ball milling time is 6 hours and the rotation speed is 500 rpm to obtain a processed nano-reinforced phase;

[0135] S6: compounding the alloy melt and the treated nano-reinforced phase by melt infiltration, wherein the temperature during melt infiltration is controlled at 1300° C. for 15 minutes, and then rapidly cooled to room temperature to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix;

[0136] S7: heating the composite material, and stretching the composite material after heating it to 1100° C., with a stretching speed of 1 mm / s and a stretching ratio of 1.5:1, to obtain stretched oxygen-free copper microtubes;

[0137] S8: heat treating the stretched oxygen-free copper microtube at a temperature of 700°C for 2 hours, and then cooling to room temperature at a rate of 10°C / min to eliminate internal stress;

[0138] S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

[0139] Specifically, in S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

[0140] Comparative Example 1

[0141] An oxygen-free copper microtube and its preparation process are basically the same as those of the fourth embodiment, except that the carbon nanotube and its related processing steps are omitted.

[0142] Comparative Example 2

[0143] An oxygen-free copper microtube and a preparation process thereof are basically the same as those of the fourth embodiment, except that the modified silane coupling agent and related processing steps are omitted.

[0144] Comparative Example 3

[0145] An oxygen-free copper microtube and a preparation process thereof are basically the same as those of the fourth embodiment, except that aluminum oxide and related processing steps are omitted.

[0146] Comparative Example 4

[0147] An oxygen-free copper microtube and a preparation process thereof are basically the same as those of the fourth embodiment, except that the heat treatment step is omitted.

[0148] The oxygen-free copper microtubes prepared in the above-mentioned Examples 1 to 4 and Comparative Examples 1 to 4 were tested:

[0149] Chemical composition test: According to the national standard GB / T 5231-2001, the chemical composition of oxygen-free copper must meet certain requirements, among which the copper content should be greater than 99.95%, the oxygen content should not exceed 0.003%, and the total impurity content should not exceed 0.05%. During the test, spectral analysis, chemical analysis and other methods can be used to determine the content of each element.

[0150] Mechanical property test: including the test of tensile strength, yield strength, elongation and other indicators. These tests can be carried out according to GB / T 228.1-2010 "Metallic material tensile test Part 1: Room temperature test method". The oxygen-free copper micro-tube sample is stretched by a tensile testing machine, and its stress-strain curve is recorded to obtain the relevant mechanical property data.

[0151] Microstructure observation: Use a metallographic microscope to observe and analyze the microstructure of oxygen-free copper microtubes to understand their internal structure and crystallinity. This can be done in accordance with GB / T 13298-2015 "Methods for the inspection of metal microstructures". By observing the microstructure, the purity of oxygen-free copper and the presence of impurities and defects can be determined.

[0152] Thermal conductivity test: Thermal conductivity is one of the important properties of oxygen-free copper microtubes, which can be evaluated by measuring its thermal conductivity. According to GB / T 11205-2009 "Determination of thermal conductivity - hot wire method", the thermal conductivity of oxygen-free copper microtubes is measured by the hot wire method.

[0153] The results are shown in Table 1:

[0154] Table 1

[0155]

[0156]

[0157] From Table 1 above, it can be directly obtained that the tensile strength of Example 1 is 380 MPa, and that of Example 2 is also 380 MPa. The tensile strengths of Example 3 and Example 4 are respectively increased to 400 MPa. In Example 3 to Example 4, the tensile strength of the material is enhanced due to the optimization of process conditions. The tensile strength is the ability of a material to resist fracture during the stretching process, and its improvement means that the material can withstand greater tensile forces without breaking.

[0158] In terms of yield strength, Example 1 is 320MPa, Example 2 increases to 360MPa, Example 3 slightly decreases to 350MPa, and Example 4 further increases to 380MPa. Yield strength is the stress point at which the material begins to undergo plastic deformation. Its increase indicates that the material can maintain better shape stability when subjected to external forces. The fluctuation of the data reflects the complex influence of different component contents and process conditions on the yield characteristics of the material.

[0159] In terms of elongation, the elongation of Examples 1 and 3 is 28%, Example 2 is slightly lower at 26%, and Example 4 reaches the highest 30%. The elongation reflects the plastic deformation ability of the material during the stretching process. The high elongation of Example 4 means that the plastic deformation ability of the material is significantly improved under the composition ratio and process conditions, which is very beneficial in certain applications that require the material to have good ductility.

[0160] In terms of thermal conductivity, the thermal conductivity of Example 1 is 420W / (m·K), while that of Example 2 and Example 4 is slightly higher at 440W / (m·K) and 450W / (m·K), respectively, and that of Example 3 reaches the highest at 460W / (m·K). Thermal conductivity is the ability of a material to conduct heat, and its improvement means that the material can transfer heat more efficiently. This is a very important performance parameter in application scenarios that require efficient heat conduction.

[0161] Reference Figure 1-2 In the comparison between Example 4 and Comparative Example 1, the carbon nanotubes and the related processing steps are omitted in Comparative Example 1. The addition of carbon nanotubes significantly improves the various properties of oxygen-free copper microtubes. This is because carbon nanotubes have excellent mechanical properties and thermal conductivity, and can effectively enhance the tensile strength, yield strength, elongation and thermal conductivity of the base material.

[0162] In Comparative Example 2, the modified silane coupling agent and its related processing steps are omitted, and the addition of the modified silane coupling agent improves the performance of the oxygen-free copper microtubes. This is because the modified silane coupling agent improves the interface bonding between the carbon nanotubes and the matrix material, allowing the carbon nanotubes to better play a reinforcing role.

[0163] In the comparison between Example 4 and Comparative Example 3, the aluminum oxide and its related processing steps are omitted in Comparative Example 3. The addition of aluminum oxide has a positive effect on the performance of oxygen-free copper microtubes. Aluminum oxide, as a hard ceramic particle, improves the tensile strength and yield strength of the material through the dispersion strengthening mechanism. At the same time, it contributes to the thermal conductivity of the material.

[0164] In the comparison between Example 4 and Comparative Example 4, the heat treatment step is omitted in Comparative Example 4. The heat treatment step is crucial to the performance of oxygen-free copper microtubes. Heat treatment can eliminate stress inside the material and improve the grain structure, thereby improving the mechanical properties and thermal conductivity of the material. Omitting the heat treatment step results in a significant decrease in the performance of Comparative Example 4.

[0165] The latest application of modified silane coupling agent in metal anti-corrosion pretreatment is that it can deposit a very thin layer of organic silane film on the metal surface, thereby greatly improving the adhesion of the paint film, as well as the ability to resist corrosion, friction and impact. Based on this, the coupling agent is used in oxygen-free copper microtubes.

[0166] The modified silane coupling agent in the present invention plays the role of both anti-biofilm material and hydrophobic material. Firstly, it effectively prevents the attachment of biofilm to the inner wall of microtubes and reduces the risk of microtube blockage. Secondly, it reduces the surface tension of the inner wall of microtubes, reduces the resistance of fluid in the tube, and improves the fluid transport efficiency.

[0167] The coupling agent itself is an organosilicon compound with a special structure. Its molecules contain reactive groups that can bind to inorganic materials and reactive groups that can bind to organic materials. This unique structure enables the coupling agent to exhibit the functions of modified silane coupling agent and modified organosilicon at the same time.

[0168] Specifically, the inorganic-philic groups in the coupling agent can react with the chemical groups on the surface of inorganic materials (such as metals, glass, etc.) to form strong chemical bonds. The organic-philic groups can react or physically entangle with organic molecules, thereby achieving chemical bonding at the interface between organic and inorganic materials. This dual mechanism of action enables the coupling agent to significantly improve the bonding strength and compatibility between different materials.

[0169] In addition, the structural gradient is achieved by changing the microstructure of oxygen-free copper (such as grain size, morphology, porosity, etc.). The present invention can make different parts of the oxygen-free copper microtube have different grain structures and porosities through methods such as heat treatment or mechanical processing, thereby affecting its thermal conductivity, corrosion resistance and mechanical properties.

[0170] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An oxygen-free copper microtube, characterized in that: The invention comprises the following components in parts by weight: 60-80 parts of oxygen-free copper, 1-5 parts of manganese, 0.1-1 parts of phosphorus, 1-5 parts of zinc, 2-10 parts of nickel, 0.5-5 parts of carbon nanotubes, 0.1-1 parts of modified silane coupling agents, 1-5 parts of aluminum oxide, 0.5-5 parts of boron nitride and 0.1-1 parts of graphene.

2. The oxygen-free copper microtube according to claim 1, characterized in that: The invention comprises the following components in parts by weight: 65 parts of oxygen-free copper, 3 parts of manganese, 0.5 parts of phosphorus, 3 parts of zinc, 7 parts of nickel, 2.5 parts of carbon nanotubes, 0.4 parts of modified silane coupling agent, 2 parts of aluminum oxide, 1.5 parts of boron nitride and 0.6 parts of graphene.

3. The oxygen-free copper microtube according to claim 1, characterized in that: The oxygen-free copper has a purity of 4N, a grain size of 5-50 microns, and a face-centered cubic structure. The median particle size of the manganese is 2-6 microns, and the manganese exists in the form of a solid solution or a fine precipitate phase, the size of the precipitate phase is 10-80 nanometers, the shape of the manganese particles is approximately spherical, and the particle ellipticity is less than 1.2, the phosphorus is introduced in the form of copper phosphide or phosphorus alloy, and the phosphorus element is evenly distributed at the grain boundary to reduce the impact on the intracrystalline performance, the zinc uses zinc powder with an average particle size of 5-20 microns, and the nickel is evenly dispersed in the oxygen-free copper matrix in the form of fine precipitates, and the size of the precipitates is 50-200 nanometers; The carbon nanotubes have a diameter of 10-50 nanometers and an average length of 1-10 micrometers; The molecular structure of the modified silane coupling agent has at least one functional group that reacts with the surface of oxygen-free copper and one functional group that is compatible with the organic phase, and the molecular chain length of the modified silane coupling agent is 10-20 carbon atoms; The average particle size of the aluminum oxide is 0.1-1.0 microns; The average particle size of the boron nitride is controlled to be 0.5-5.0 microns, and the boron nitride has a hexagonal crystal structure; The number of graphene layers is 1-5, and the average sheet diameter is 1-10 microns.

4. The oxygen-free copper microtube according to claim 1, characterized in that: The structural gradient of the oxygen-free copper is induced by heat treatment to form a gradually changing grain size along the length or diameter direction of the microtube, and a gradual structure from nanocrystalline to microcrystalline, so as to enhance the local strength and thermal conductivity of the microtube; The manganese is added to the oxygen-free copper in a gradient distribution manner, with the content gradually increasing from the inner layer to the outer layer. Through a heat treatment process, the manganese is uniformly dispersed in the form of approximately spherical nano-precipitates, which can serve as a reinforcing agent to improve the strength and ductility of the material. The phosphorus is enriched at the oxygen-free copper grain boundary to form a stable copper phosphide interface phase; The carbon nanotubes are arranged in a Y-shaped orderly orientation to maximize their mechanical and electrical properties along the Y-shaped direction, and functional groups compatible with the oxygen-free copper matrix are introduced by chemically modifying the surface of the carbon nanotubes; The aluminum oxide has optical properties, including fluorescence or reflection, which introduces additional optical functions into the microtubes; The boron nitride forms a continuous heat-conducting network to improve the overall thermal conductivity of the microtube; The graphene is uniformly dispersed in the oxygen-free copper matrix in the form of molecular clusters, and these molecular clusters can serve as electrical and thermal conduction channels.

5. The oxygen-free copper microtube according to claim 1, characterized in that: The inorganic-philic group of the modified silane coupling agent can form a strong chemical bond with the oxygen-free copper surface. The bonding strength between the modified silane coupling agent and the oxygen-free copper surface is set to S, then: S=k_1\cdotA\cdot\exp(-E_a / (R\cdotT)) Among them, k_1 is the pre-exponential factor, which represents the rate constant of the bonding reaction; A is the reaction surface area, that is, the area where the oxygen-free copper surface contacts the coupling agent; E_a is the activation energy, which represents the energy required for the bonding reaction; R is the gas constant; T is the reaction temperature; The organophilic groups can effectively combine with the reinforcing phase of carbon nanotubes to achieve cross-scale interface enhancement. The combination efficiency E of carbon nanotubes and modified silane coupling agents is: E=k_2\cdotC\cdot\sigma Wherein, k_2 is the binding constant, which indicates the strength of the binding between carbon nanotubes and modified silane coupling agent; C is the dispersion of carbon nanotubes; \sigma is the surface tension of carbon nanotubes; The modified silane coupling agent forms a primary pre-network and a secondary pre-network inside the microtube to construct a three-dimensional cross-linked structure, and the strength of the three-dimensional cross-linked structure is I: I=S\cdotE\cdotN Among them, S is the bonding strength between the modified silane coupling agent and the oxygen-free copper surface, E is the bonding efficiency between the carbon nanotubes and the modified silane coupling agent, and N is the number of cross-linking points, that is, the number of cross-linking points formed by the coupling agent molecules in the microtubes.

6. A process for preparing oxygen-free copper microtubes according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1: Select high-purity oxygen-free copper as the base material, melt it and cast it into copper ingots; S2: prepare manganese, phosphorus, zinc and nickel alloy elements respectively, add these elements into the melting furnace in the form of powder or small pieces, and melt them together with oxygen-free copper to form a uniform alloy melt; S3: Select high-quality carbon nanotubes, perform acid washing and purification to remove impurities, and introduce active groups on their surfaces to facilitate subsequent interface bonding to obtain pretreated carbon nanotubes; S4: dissolving the modified silane coupling agent in an organic solvent to form a uniform solution, then adding the pretreated carbon nanotubes into the organic solvent, and uniformly coating the surface of the carbon nanotubes with a layer of the modified silane coupling agent through stirring and ultrasonic treatment; S5: preparing aluminum oxide, boron nitride and graphene nano-reinforced phases, and using a high-energy ball milling method to make these materials exist in powder form to obtain a processed nano-reinforced phase; S6: compounding the alloy melt with the treated nano-reinforced phase by melt infiltration to ensure uniform distribution of the nano-reinforced phase in the oxygen-free copper matrix; S7: heating the composite material and then performing a stretching process to obtain a stretched oxygen-free copper microtube; S8: heat treating the stretched oxygen-free copper microtube to eliminate internal stress; S9: Post-processing the heat-treated oxygen-free copper micro-tube to obtain a finished product.

7. The process for preparing an oxygen-free copper microtube according to claim 6, characterized in that: In the S2, rare earth elements are introduced as antioxidants to reduce oxidation losses, and inert gas protection is used to reduce oxidation risks.

8. The process for preparing an oxygen-free copper microtube according to claim 6, characterized in that: In the S3, carbon nanotubes with a diameter of 10-50 nanometers and a length of 1-10 microns are selected for pickling and purification. A 3M nitric acid solution is used for pickling. The treatment time is 10-12 hours at a temperature of 60-80°C. The purified carbon nanotubes are dried in a vacuum oven at 80°C for 12-16 hours to remove impurities, and active groups are introduced on their surfaces to facilitate subsequent interface bonding, thereby obtaining pretreated carbon nanotubes.

9. The process for preparing an oxygen-free copper microtube according to claim 6, characterized in that: In S4, the modified silane coupling agent is selected from the type with a molecular chain length of 10-20 carbon atoms, and the organic solvent is selected from ethanol. The modified silane coupling agent is dissolved in the organic solvent to form a uniform solution. Subsequently, the pretreated carbon nanotubes are added to the organic solvent, and stirred and ultrasonically treated at a stirring speed of 500-1000 rpm and an ultrasonic treatment time of 30-45 minutes to uniformly coat the surface of the carbon nanotubes with a layer of modified silane coupling agent.

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