High-strength and high-conductivity composite conductor material for high-stability special cable, preparation method of high-strength and high-conductivity composite conductor material and cable application

Abstract

The invention discloses a high-strength and high-conductivity composite conductor material for a high-stability special cable, a preparation method of the high-strength and high-conductivity composite conductor material and cable application, and belongs to the technical field of special cable conductor materials. According to the invention, a graphene-BN interlocking structure is innovatively constructed, so that the BN layer and a surface graphene network form a three-dimensional communicated heat dissipation path. The edge of a graphene sheet layer and a BN layer form covalent bond connection, the thermal expansion coefficient of BN is between that of graphene and a copper substrate, a continuous thermal expansion coefficient gradient is formed, huge thermal stress caused by extreme temperature difference is effectively buffered and redistributed, and microcracks caused by stress concentration at a certain interface are avoided. The stability and the conductivity retention rate gt of the material under an extreme temperature cycle of-150 DEG C to + 200 DEG C are obviously improved; the strength retention rate is gt; the conductivity attenuation rate after radiation of 500 krad is as high as 1t; and after simulated atomic oxygen is exposed, the surface is free of erosion, which is far better than that in the prior art.

Description

Technical Field

[0001] This invention relates to a high-strength, high-conductivity composite conductor material for high-stability special cables, its preparation method, and its cable application, belonging to the technical field of special cable conductor materials. Background Technology

[0002] In modern industry and cutting-edge technology, special cables serve as the "nerves" and "blood vessels" of energy and information transmission, and their reliability directly determines the safety and efficiency of the entire system. With the rapid development of deep space exploration, long-term on-orbit space stations, and other endeavors, the performance requirements for special cables have reached unprecedented levels.

[0003] In the extreme and complex environment of space, the core conductor material of the cable faces multiple stringent challenges: First, the space environment exhibits extreme temperature fluctuations, requiring the cable to remain stable between the -150°C of shadowy low temperatures and the +200°C of direct sunlight or the high temperatures generated by equipment; second, the material must be able to withstand the intense cosmic radiation environment with cumulative doses ranging from 300 krad to 1 Mrad; and third, in near-Earth orbit, it must resist the continuous erosion of atomic oxygen. Under such extreme conditions, any performance degradation of the cable conductor material could directly lead to system failure or even mission failure.

[0004] Currently, traditional conductor materials exhibit significant performance limitations when facing the extreme environments of space. Pure copper or conventional copper alloys develop numerous lattice defects under strong radiation, leading to a sharp increase in resistivity and a marked deterioration in signal transmission quality. During severe temperature cycling, these materials are prone to creep and fatigue damage, severely impacting their mechanical integrity. While traditional high-strength, high-conductivity copper alloys, such as chromium-zirconium copper, improve strength to some extent through solid solution strengthening, they introduce a large number of solute atoms, severely scattering electrons and causing a significant drop in conductivity to below 80% IACS, failing to meet the extremely high conductivity requirements of space cables.

[0005] More importantly, while existing graphene-copper composite technologies have addressed the balance between strength and conductivity to some extent, their design is primarily geared towards conventional environments and lacks specific design considerations for the unique conditions of space. When subjected to extreme temperature cycling, the significant difference in thermal expansion coefficients between graphene and the copper matrix can easily lead to microcracks at the interface. Under long-term radiation, the irradiation swelling effect of the copper matrix can disrupt the integrity of the three-dimensional network, resulting in accelerated performance degradation. These deep-seated stability issues make it difficult for existing graphene-copper composites to operate reliably in the space environment for extended periods.

[0006] Therefore, there is an urgent need in this field to develop a new type of high-strength, high-conductivity composite conductor material for high-stability special cables. This not only requires solving the fundamental problem of graphene dispersion and interfacial bonding, but also requires starting from the material system design level to provide a conductor material that can maintain stable performance over a long period of time under harsh conditions such as ultra-wide temperature range and strong radiation, specifically designed for the characteristics of the extreme space environment, so as to meet the stringent requirements of next-generation spacecraft for special cables. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a high-strength, high-conductivity composite conductor material for high-stability special cables, which combines high strength, high stability and high radiation resistance.

[0008] Meanwhile, this invention provides a method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables. This method constructs a "graphene-BN interlocking structure," enabling the BN layer and the surface graphene network to form a three-dimensional interconnected heat dissipation pathway. This effectively buffers and redistributes the enormous thermal stress caused by extreme temperature differences, preventing stress concentration at a certain interface and the initiation of microcracks.

[0009] Meanwhile, this invention provides an application of a high-strength, high-conductivity composite conductor material for high-stability special cables in space cables.

[0010] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables, the main process steps of which are as follows: S1, Preparation of multi-element copper alloy powder: Pre-alloyed powder is prepared using gas atomization technology. High-purity copper (≥99.99%), intermediate alloys Cu-Zr and Cu-Mo, and pure silver ingots are batched according to the target composition, melted and fully homogenized in a vacuum induction melting furnace, and then atomized into fine droplets by high-pressure inert gas (such as argon), which rapidly solidifies to form spherical powder, i.e., multi-element copper alloy powder.

[0011] S2, Functionalization modification of graphene oxide: Aqueous dispersions of graphene oxide (GO) were prepared by oxidation. Subsequently, GO was cationically modified. Specifically, GO was dispersed in deionized water by ultrasonic stirring, and an appropriate amount of polyethyleneimine (PEI) (a cationic modifier) ​​was added to adjust the pH of the solution to alkaline, thereby modifying the GO surface with positively charged functional groups to obtain a cationic GO dispersion.

[0012] S3, Electrostatic self-assembly and ball milling to construct core-shell structures: The multi-element copper alloy powder prepared in S1 was mixed with the cationic GO dispersion obtained in S2 at a mass ratio of 100:(0.5-3.0), and the core-shell structure was constructed based on the dual-drive force synergistic assembly mechanism. S31, electrostatic attraction-driven preliminary assembly: The negative potential of the micro-region formed by the component segregation on the surface of multi-element copper alloy powder is used to generate strong electrostatic adsorption with the positively charged functional groups on the surface of cationized GO, so that the GO sheets are initially uniformly attached to the surface of copper powder particles to form a pre-assembled structure. S32, coordination bonding enhances the interfacial effect: by adding 0.05-0.1wt% of an aminosilane coupling agent (preferably γ-aminopropyltriethoxysilane) to the mixed slurry, one end of which forms a hydrogen bond with the amino group on the GO surface, and the other end undergoes a condensation reaction with the hydroxyl group on the copper powder surface to form coordination bonding sites, transforming physical adsorption into a dual effect of "electrostatic adsorption-chemical bonding", thereby improving the interfacial bonding stability between GO and copper powder; S33. Precise control of coating effect through staged ball milling: A three-stage low-speed wet ball milling process is used to achieve uniform coating and structural optimization of GO. First stage (0-2h): Rotation speed 100-150rpm, ball-to-powder ratio 8:1~9:1, using low-energy impact to spread the GO flakes along the copper powder surface, initially eliminating interface gaps; Second stage (2-6h): Rotation speed 150-200rpm, ball-to-material ratio 9:1~10:1, medium energy grinding causes GO flakes to undergo moderate peeling and reconstruction, forming a dense coating layer; The third stage (6-8h): 100-150rpm, ball-to-material ratio 8:1~9:1, low temperature (≤40℃) ball milling to eliminate internal stress in the coating layer, so that the core-shell structure interface can be fused without defects.

[0013] The process control agent uses a mixture of anhydrous ethanol and glycerol (volume ratio 95:5), and the addition amount is 1-3 vol% of the total powder mass, which ensures dispersibility and avoids GO sheet agglomeration.

[0014] S4, Spray drying and thermal reduction of composite powder: The ball-milled slurry was rapidly dried and granulated using a spray dryer to obtain spherical composite powder with good flowability. Subsequently, the dried powder was heat-treated in a reducing atmosphere to remove the oxygen-containing functional groups on the GO surface, transforming it into reduced graphene oxide with excellent conductivity.

[0015] S5, Densification by Spark Plasma Sintering: The reduced core-shell composite powder is loaded into a graphite mold and placed into the cavity of a spark plasma sintering equipment. Under vacuum conditions, the powder particles are instantly activated and their surfaces are cleaned by the high temperature generated by the pulsed direct current and the uniaxial pressure applied simultaneously. This results in rapid plastic flow and diffusion welding, achieving a nearly fully dense sintered body in a very short time.

[0016] S6, Ion implantation of surface boron nitride gradient layer: The sintered and dense composite material sample was placed in the vacuum chamber of a multifunctional ion implantation and deposition composite device, and a BN gradient protective layer was prepared using a dual-source co-implantation-in-situ annealing synergistic process. The specific steps are as follows: S61, Pretreatment stage: The sample surface is plasma cleaned using argon as the cleaning gas, with a plasma power of 300-400W and a cleaning time of 15-20 minutes. This removes adsorbed oxygen impurities and contaminants from the surface, activates surface atoms, and maintains a target chamber vacuum of ≤5×10⁻⁶. -4 Pa; S62, Gradient Injection Stage 1: Using diborane (B2H6, purity 99.99%) and nitrogen (N2, purity 99.99%) as source gases, with a source gas flow ratio of B2H6:N2 = 1:3-1:5, injection energy 5-8 keV, and injection dose 5 × 10⁻⁶. 16 -1×10 17 ions / cm 2 During this stage, a B-rich BN transition layer is formed in the 10-30nm region on the surface of the material, achieving gradient connection with the substrate; S63, Gradient Injection Second Stage: Maintaining the source gas flow rate ratio constant, increase the injection energy to 12-15 keV, and the injection dose is 1×10⁻⁶. 17 -1.5×10 18 ions / cm 2 During this stage, the ion penetration depth reaches 30-80 nm, forming the BN host layer. Energy modulation is then used to enable B... + and N + Uniform ion distribution ensures the homogeneity of composition within the layer; S64, Gradient Injection Stage 3: Adjust the source gas flow ratio B2H6:N2 = 1:6-1:8, injection energy 18-20keV, injection dose 1.5×10⁻⁶. 17 -2×10 17 ions / cm 2 During this stage, a nitrogen-rich BN surface layer is formed in the 80-150nm region, enhancing the surface antigen oxygen erosion capability, while maintaining the target chamber vacuum level ≤1×10 throughout the process. -3 Pa; S65, In-situ annealing: After implantation, in-situ annealing is performed under an argon protective atmosphere. The annealing temperature is 400-450℃, the holding time is 30-60min, and the heating rate is 4-5℃ / min. Annealing eliminates lattice defects generated during implantation, promotes BN grain refinement and orientation optimization, and enhances the interfacial bonding strength between the BN layer and the matrix and surface graphene network. S66, Post-processing stage: Plasma polishing technology is used to finely treat the surface with a power of 180-200W and a processing time of 4-5 minutes to remove residual micro-protrusions and impurities on the surface, and obtain a smooth BN gradient layer. The final BN layer thickness is precisely controlled at 50-150nm, and the composition is distributed in a continuous gradient (the B content gradually decreases and the N content gradually increases from the substrate to the surface).

[0017] Preferably, in S1, the alloy composition is selected as follows: Zr: 0.1-0.5 wt%, Mo: 0.2-1.0 wt%, Ag: 0.1-0.5 wt%, with the balance being Cu; the atomizing gas pressure is 3.0-8.0 MPa; and the powder particle size is selected as spherical powder with a particle size of 15-45 μm.

[0018] Preferably, in S1, during the melting stage: after evacuating to ≤5Pa, the temperature is increased to 1350-1450℃ at a heating rate of 8-12℃ / s, and held for 15-30 minutes.

[0019] Homogenization stage: Continue to keep warm at 1300-1400℃ for 30-60 minutes, supplemented by electromagnetic stirring (frequency 30-50Hz).

[0020] Preferably, in S2, the concentration of GO dispersion is 1-3 mg / mL; the amount of polyethyleneimine added is 10%-30% of the mass of GO; the pH adjustment range is 8.5-10.0; and the ultrasonic treatment power and time are 200-500 W for 0.5-2 h.

[0021] Preferably, in S4, the spray drying inlet temperature is 180-220℃; the thermal reduction temperature is 450-600℃; and the thermal reduction atmosphere and time are: argon / hydrogen mixture (hydrogen volume content 5-10%), and the temperature is maintained for 1-2 hours.

[0022] Preferably, in S5, the sintering temperature is 900-1000℃; the sintering pressure is 40-60MPa; the heating rate is 100-200℃ / min; the holding time is 5-15min; and the vacuum degree is ≤10Pa.

[0023] The present invention relates to a high-stability, high-strength, high-conductivity composite conductor material for high-stability special cables. The surface of the composite conductor material has a BN gradient layer with a thickness of 50-150 nm and a continuous gradient composition distribution, where the B content gradually decreases and the N content gradually increases from the matrix to the surface. The BN gradient layer and the surface graphene network form a three-dimensional interconnected heat dissipation pathway. Specifically, the composite conductor material forms a continuous compositional gradient distribution with a surface B:N ratio of 1:1.5, an interface B:N ratio of 1:1.0, and a matrix B:N ratio of 1:0.5.

[0024] The high-strength, high-conductivity composite conductor material for high-stability special cables of the present invention maintains a conductivity retention rate of >98% and a strength retention rate of >99% under extreme temperature cycling from -150℃ to +200℃. After 500 krad radiation, the conductivity decay rate is <3%, and there is no surface corrosion after simulated atomic oxygen exposure.

[0025] The application of the high-strength, high-conductivity composite conductor material for high-stability special cables of the present invention in space cables.

[0026] A space cable is prepared from the high-strength, high-conductivity composite conductor material for high-stability special cables of the present invention.

[0027] The formation mechanism of hydroxyl groups (-OH) on the surface of copper powder in this invention: In this invention, the hydroxyl groups on the surface of the multi-element copper alloy powder are not actively added during the S1 preparation stage, but are formed spontaneously through surface oxidation and water vapor adsorption after the powder is exposed to the atmospheric environment. This is an inherent surface characteristic of metal powders, and its specific formation mechanism is as follows: Preliminary formation of the surface oxide film: In S1, the multi-element copper alloy powder prepared by gas atomization is a spherical ultrafine powder (15-45μm) with a large specific surface area and surface activity. After the powder is atomized and cooled in a vacuum induction melting furnace, when exposed to the atmospheric environment, the surface atoms rapidly react with oxygen in the air to form an extremely thin (1-5nm) oxide film. The oxide film is mainly composed of Cu2O, CuO, and a small amount of ZrO2 and MoO3 (because the alloy contains Zr and Mo elements, their oxidation activity is higher than that of Cu, and they will preferentially form oxides). Hydrolysis of oxide film with water vapor: Trace amounts of water vapor (H2O) exist in the atmosphere. The metal oxides in the oxide film will spontaneously hydrolyze with the water vapor to generate surface hydroxyl groups. Taking copper oxide as an example, the reaction formula is as follows: Cu2O + H2O → 2Cu-OH (cuprous oxide hydrolyzes to generate hydroxyl groups); CuO + H2O → Cu(OH)2 → Surface Cu-OH (copper oxide reacts with water to form copper hydroxide, and after further dehydration, residual surface hydroxyl groups remain). Meanwhile, oxides such as ZrO2 and MoO3 in the alloy also undergo similar hydrolysis reactions: ZrO2 + H2O → Zr(OH)2 → Surface Zr-OH; MoO3 + H2O → H2MoO4 → Surface Mo-OH, ultimately forming a uniformly distributed hydroxyl (-OH) layer on the surface of the alloy powder; Stability assurance of hydroxyl groups: The hydroxyl layer is a composite form of physical adsorption and chemical bonding. The chemically bonded hydroxyl groups (forming covalent bonds with metal atoms) have good stability in subsequent processes (such as spray drying and thermal reduction pretreatment), which is sufficient to support the condensation reaction with the aminosilane coupling agent in S3. They will not be completely decomposed by the subsequent thermal reduction process (450-600℃) (only the physically adsorbed hydroxyl groups will desorb, and the chemically bonded hydroxyl groups can be retained in the reducing atmosphere until the sintering stage, and finally the interface is strengthened in synergy with ZrC through sintering).

[0028] In summary, the negative potential of the micro-regions on the surface of multi-element copper alloy powder is the result of the synergistic effect of component segregation and plasma charging during gas atomization. The negative charge density can be quantitatively controlled by precisely adjusting the atomization process parameters. The specific mechanism is as follows: (a) Core formation mechanism: Differences in surface electronegativity caused by component segregation: Micro-segregation of components during gas atomization: In S1, vacuum induction melting is used to alloy Cu, Cu-Zr, Cu-Mo, and Ag. The alloys are then atomized into droplets by high-pressure inert gas (argon) and rapidly solidified (cooling rate can reach 10). 4 -10 5 (℃ / s). Due to insufficient atomic diffusion during rapid solidification, the alloy composition cannot be completely homogenized, leading to micro-regional compositional agglomeration on the powder surface: Zr and Mo are high-melting-point metals (Zr melting point 1852℃, Mo melting point 2623℃). They are difficult to completely dissolve in the Cu matrix during rapid solidification, and will form nanoscale Zr-rich and Mo-rich micro-regions (particle size 20-50nm) on the powder surface. Ag is a low-melting-point metal (melting point 961℃) and tends to agglomerate on the powder surface to form Ag-rich microregions (mainly distributed at powder surface defects or grain boundaries).

[0029] The difference in surface electronegativity caused by compositional segregation: Different elements have different electronegativity (Cu electronegativity 1.90, Zr electronegativity 1.33, Mo electronegativity 2.16, Ag electronegativity 1.93), and the compositional differences in surface microregions lead to uneven electronegativity distribution. The Mo-rich microregion (electronegativity 2.16) has a higher electronegativity than the Cu matrix (1.90), which attracts surrounding electrons to accumulate in the microregion. Zr-rich microregions (electronegativity 1.33) have lower electronegativity than the matrix and will lose electrons and release charge to the surroundings; Overall, the electron aggregation effect of Mo-rich microregions is dominant (because Mo has a higher atomic number and stronger electron adsorption capacity), and the electronegativity of Ag-rich microregions (1.93) is close to that of Cu matrix, which does not significantly change the charge distribution. Ultimately, this results in the entire powder surface exhibiting an overall microregion negative potential (potential range: -100~-30mV, detectable by a zeta potentiometer).

[0030] (II) Precise control logic of atomization process parameters (refined control mechanism of 3-8MPa pressure and 15-45μm particle size): By adjusting the atomizing gas pressure and powder particle size, the surface negative charge density (absolute value of negative potential) can be quantitatively controlled. The core logic is as follows: The regulating effect of atomizing gas pressure (3-8 MPa): Pressure affects the degree of droplet fragmentation and cooling rate: the higher the pressure (within the range of 3-8 MPa), the stronger the impact force of argon on the molten metal flow, the finer the droplet fragmentation, and the faster the cooling rate (up to 10). 5 ℃ / s), the more significant the component segregation (elements such as Mo and Zr are more difficult to diffuse, and the higher the concentration in surface micro-regions); Enhanced charge adsorption effect: During high-pressure atomization, argon molecules collide violently with metal droplets, generating a plasma effect (electrons on the surface of the metal droplets are excited into free electrons). The high-pressure environment promotes the adsorption of free electrons in the Mo-rich micro-region, thus increasing the negative charge density. Control threshold: When the pressure is below 3 MPa, the droplets break up into large particles (particle size > 50 μm) and the cooling rate is insufficient (< 10). 4 ℃ / s), weak component segregation, and insufficient negative charge density (<10). -6 C / cm 2 The powder cannot effectively adsorb cationic GO. When the pressure is higher than 8 MPa, the powder particles are too fine (<10 μm), and the surface area is too large, which leads to increased surface oxidation. The oxide film thickness exceeds 5 nm, which will shield the surface negative potential and also affect the adsorption effect.

[0031] The controlling effect of powder particle size (15-45μm): Specific surface area and surface energy balance: When the particle size is 15-45 μm, the specific surface area (0.1-0.5 m²) is relatively stable. 2 The surface energy (50-100 mJ / m²) is moderate. 2 It is sufficient to maintain the negative potential formed by component segregation and will not cause excessive oxidation due to excessively fine particle size; Micro-region distribution uniformity: Within this particle size range, the distribution density of Mo-rich micro-regions on the surface (102...). 3 -10 4 per μm2 The material is uniform, with no obvious blind spots in the distribution of negative charge, which allows for full contact and adsorption with GO sheets. Charge stability: When the particle size is >50μm, the surface micro-regions are not sufficiently aggregated, and the negative charge density is low and unevenly distributed; when the particle size is <10μm, the surface oxide film is too thick, and the negative potential is shielded, neither of which can meet the requirements of electrostatic self-assembly.

[0032] The present invention has the following beneficial effects: 1. The core of this invention lies in achieving enhanced intrinsic stability of the matrix under extreme space conditions through the synergistic effect of various elements. Zr, as a key interfacial active element, preferentially segregates at the graphene / copper interface, reacting in situ with carbon atoms to generate nanoscale ZrC. ZrC and graphene have excellent lattice matching, forming a strong coherent or semi-coherent interface. This transforms the traditional weak physical bonding into a strong chemical bond, significantly improving interfacial bonding energy and thermal stability, thereby effectively suppressing interfacial debonding and failure caused by the mismatch of the two phases' thermal expansion coefficients during severe thermal cycling. The addition of Mo mainly plays a role in solid solution strengthening and radiation resistance. Its high melting point and extremely low radiation swelling sensitivity can effectively pin grain boundaries, stabilize the crystal structure of copper, and inhibit the aggregation and growth of defects such as vacancies and interstitial atoms under strong radiation, fundamentally improving the matrix's radiation resistance. While providing additional solid solution strengthening and improving conductivity, Ag's properties also help promote densification during sintering, reduce micropores, and eliminate potential stress concentration points and radiation-sensitive defects. In summary, this multi-element alloying design, through the synergy of interface modification (Zr), matrix stabilization (Mo), and process optimization (Ag), constructs a metallic matrix that combines high strength, high stability, and high radiation resistance.

[0033] 2. Electrostatic self-assembly mechanism with precise charge density control: This invention innovatively proposes and realizes an electrostatic self-assembly mechanism for precise charge density matching. By precisely controlling the amount of PEI added (10%-30% of GO mass) and the solution pH (8.5-10.0), the positive charge density on the GO surface is precisely regulated. Simultaneously, by adjusting the atomizing gas pressure (3-8 MPa) and powder particle size (15-45 μm), the negative charge density on the copper powder surface is precisely controlled, ensuring that the charge density matching error is controlled within ±0.2 μmol / m. 2 Within this range, Zr element generates ZrC nanophase (particle size 5-20 nm) in situ at the interface, exhibiting a lattice matching degree of over 95% with graphene, forming a strong and tough coherent or semi-coherent interface. This transforms the traditional physical adsorption interface into a robust chemically bonded interface, with interfacial bonding energy ranging from 0.5-1.0 J / m. 2 Increased to 3.5-4.0 J / m2 Meanwhile, Ag promotes densification during sintering, reduces micropores, eliminates potential stress concentration points and radiation-sensitive defects, enabling graphene to achieve a coating rate of over 95% on the copper powder surface, with a coating thickness uniformity of ±5 nm, far exceeding the coating uniformity of existing technologies (approximately 70%).

[0034] 3. Three-stage graded ball milling process and construction of uniform core-shell structure: This invention innovatively develops a three-stage graded ball milling process. By precisely controlling the ball milling speed, ball-to-powder ratio, and milling time, uniform and dense coating of graphene on the surface of copper powder is achieved. The first stage (low-speed ball milling, 100-150 rpm, 2 h): preliminary mixing to prevent graphene agglomeration; the second stage (medium-speed ball milling, 150-200 rpm, 4 h): enhancing electrostatic adsorption to ensure uniform graphene adhesion; the third stage (low-speed, low-temperature ball milling, 100-150 rpm, 2 h): achieving dense coating of graphene on the copper powder surface. Zr element generates ZrC nanophase in situ, forming strong chemical bonds with graphene, while Ag element promotes sintering densification and reduces micropores, ensuring the integrity and uniformity of the graphene coating layer. This results in a graphene coating integrity of over 98% on the copper powder surface and a coating layer thickness uniformity of ±5 nm, significantly superior to traditional ball milling processes.

[0035] 4. Dual-source co-implantation-in-situ annealing synergistic process and BN gradient layer formation: This invention pioneers a "dual-source co-injection-in-situ synergistic process," achieving precise construction of the BN gradient layer through multi-stage precise control of energy, dosage, and source gas ratios. The dual-source co-injection simultaneously introduces B2H6 and N2 gas sources, enabling the BN gradient layer to be precisely constructed. + and N + Ions are simultaneously and rapidly implanted in a specific ratio, forming a continuous compositional gradient distribution of surface B:N=1:1.5, interface B:N=1:1.0, and matrix B:N=1:0.5 through three-stage gradient implantation (low dose, medium dose, high dose). The addition of Mo element exerts solid solution strengthening and radiation resistance performance. Its high melting point and extremely low radiation swelling sensitivity can effectively pin grain boundaries, stabilize the copper crystal structure, and inhibit the aggregation and growth of defects such as vacancies and interstitial atoms under strong radiation environment. At the same time, Ag element promotes densification, ensuring a tight bond between the BN layer and the matrix, solving the problem of mismatch in the thermal expansion coefficients of a single BN layer and the matrix. This allows the BN layer and graphene network to form a special "nano-bridge" structure at the interface, in which the B atoms of BN form covalent bonds with the C atoms of graphene, while the N atoms form chemical bonds with the copper matrix.

[0036] 5. Synergistic thermal management mechanism of graphene-BN interlocking structure: This invention innovatively constructs a "graphene-BN interlocking structure," enabling the BN layer and the surface graphene network to form a three-dimensional interconnected heat dissipation pathway. The edges of the graphene sheets are covalently bonded to the BN layer, and the thermal expansion coefficient of BN is between that of graphene (1.5 × 10⁻⁶). -6 / ℃) and copper matrix (17×10 -6 Between -150℃ and +200℃, a continuous gradient of thermal expansion coefficients is formed, effectively buffering and redistributing the huge thermal stress caused by extreme temperature differences, and avoiding stress concentration at a certain interface that could lead to microcracks. The combined effect of chemical bonding at the ZrC nanophase interface, the radiation resistance of Mo, and the densification effect of Ag improves the lateral heat dissipation efficiency by more than 40%, reduces stress concentration during thermal cycling by 50%, and significantly improves the stability of the material under extreme temperature cycling from -150℃ to +200℃. The conductivity retention rate is >98%, the strength retention rate is >99%, the conductivity decay rate after 500 krad radiation is <3%, and there is no surface corrosion after simulated atomic oxygen exposure, far exceeding the existing technology. Attached Figure Description

[0037] Figure 1 This is a microstructure diagram showing the complete coating of graphene on the surface of copper powder according to the present invention. Figure 2 The diagram shows the graphene network microstructure (left) and the BN gradient layer (right) of the cable of this invention. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0039] A method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables includes the following steps: S1, Preparation of multi-component copper alloy powder: Preparation was achieved using gas atomization technology at a pressure of 5.0 MPa. Spherical powder of 15-45 μm was selected. Specifically, high-purity copper, intermediate alloys Cu-Zr and Cu-Mo, and pure silver ingots were mixed, with Zr: 0.3 wt%, Mo: 0.5 wt%, Ag: 0.3 wt%, and the balance being Cu. The mixture was melted in a vacuum induction melting furnace (after evacuating to 5 Pa, heated to 1400 °C at a heating rate of 10 °C / s and held for 20 minutes) and thoroughly homogenized (further held at 1350 °C for 45 minutes with 40 Hz electromagnetic stirring). The molten metal was then atomized into fine droplets by a high-pressure inert gas (such as argon), which rapidly solidified to form spherical powder, i.e., multi-component copper alloy powder.

[0040] S2, Functionalization modification of graphene oxide: GO was dispersed in deionized water by ultrasonic stirring at 300W for 1 h, with a GO dispersion concentration of 2 mg / mL; polyethyleneimine was added at an amount of 20% of the GO mass, and the solution was stirred and the pH value of the solution was adjusted to 9.0 to obtain a cationic GO dispersion.

[0041] S3, Electrostatic self-assembly and ball milling to construct core-shell structures: The multi-element copper alloy powder prepared in S1 was mixed with the cationic GO dispersion obtained in S2 at a mass ratio of 100:1.5 to obtain a mixed slurry. 0.08 wt% of the aminosilane coupling agent γ-aminopropyltriethoxysilane was added to the mixed slurry, followed by a process control agent (a mixture of anhydrous ethanol and glycerol at a volume ratio of 95:5), with the process control agent added at 2 vol% of the total powder mass. Then, a three-stage low-speed wet ball milling process was used to achieve uniform coating and structural optimization of GO. First stage: 125 rpm, ball-to-material ratio 8:1, ball milling time 2 hours; Second stage: 180 rpm, ball-to-material ratio 9:1, ball milling time 4 hours; Third stage: rotation speed 120 rpm, ball-to-material ratio 8:1, ball milling time 2 hours, ball milling temperature 40℃; to obtain the ball-milled slurry.

[0042] S4, Spray drying and thermal reduction of composite powder: The ball-milled slurry is spray-dried; then, the dried powder is heat-treated in a reducing atmosphere to obtain the reduced core-shell structured composite powder; specifically, the spray drying inlet temperature is 200℃; the thermal reduction temperature is 500℃; the thermal reduction atmosphere and time are: argon / hydrogen mixture, hydrogen volume content is 8%, and the holding time is 1.5h.

[0043] S5, Densification by Spark Plasma Sintering: The reduced core-shell composite powder is loaded into a graphite mold and placed into the cavity of a spark plasma sintering equipment; sintering temperature: 950℃; sintering pressure: 50MPa; heating rate: 150℃ / min; holding time: 10min; vacuum degree: 10Pa; a dense sintered composite material is obtained.

[0044] S6, Ion implantation of surface boron nitride gradient layer: S61, Pretreatment stage: The surface of the sintered and dense composite material is subjected to plasma cleaning using argon as the cleaning gas, plasma power of 350W, cleaning time of 18min, and target chamber vacuum of 5×10⁻⁶. -4 Pa; S62, Gradient Injection Stage 1: Using diborane and nitrogen as source gases, the source gas flow ratio of diborane:nitrogen = 1:4, injection energy 6keV, injection dose 5×10⁻⁶. 16ions / cm 2 ; S63, Gradient Injection Second Stage: Maintaining the source gas flow rate ratio constant, increase the injection energy to 13 keV, and the injection dose to 1×10⁻⁶. 17 ions / cm 2 ; S64, Gradient Injection Stage 3: Adjust the source gas flow rate ratio of diborane:nitrogen = 1:7, injection energy 19keV, injection dose 1.5×10⁻⁶. 17 ions / cm 2 The vacuum level in the target chamber was maintained at 1×10 throughout the entire process. -3 Pa; S65, In-situ annealing: After injection, in-situ annealing is performed under an argon protective atmosphere at an annealing temperature of 420℃, a holding time of 45min, and a heating rate of 4.5℃ / min. S66, Post-processing stage: Plasma polishing technology is used to finely treat the surface with a power of 190W and a processing time of 4 minutes to obtain a high-strength and high-conductivity composite conductor material for high-stability special cables.

[0045] The high-stability, high-strength, high-conductivity composite conductor material for special cables obtained in this embodiment has a BN gradient layer on its surface. The thickness of the BN gradient layer is about 80 nm, and its composition is distributed in a continuous gradient. The B content gradually decreases from the matrix to the surface, and the N content gradually increases. The BN gradient layer and the surface graphene network form a three-dimensional interconnected heat dissipation path.

[0046] The high-strength, high-conductivity composite conductor material for high-stability special cables in this embodiment forms a continuous composition gradient distribution with surface B:N=1:1.5, interface B:N=1:1.0, and matrix B:N=1:0.5.

[0047] This embodiment describes the application of high-strength, high-conductivity composite conductor materials for high-stability special cables in space cables.

[0048] A space cable is prepared from a high-strength, high-conductivity composite conductor material for high-stability special cables, as described in this embodiment.

[0049] like Figure 1 As shown, after the S3 electrostatic self-assembly and ball milling are completed to construct the core-shell structure, graphene is completely coated on the surface of copper powder, and the dark outer layer is the copper powder completely coated by graphene.

[0050] like Figure 2 As shown in the left figure, the cable of the embodiment forms a graphene network structure, with the graphene network covering the copper substrate. The right figure shows that the graphene layer and the BN layer form a nano-bridging and interlocking structure. The contrast of the BN layer changes from light to dark, which also indicates that it forms a gradient layer. Example 2

[0051] A method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables includes the following steps: S1, Preparation of multi-component copper alloy powder: Preparation was achieved using gas atomization technology at a pressure of 3.0 MPa. Spherical powder with a diameter of 15-45 μm was selected. Specifically, high-purity copper, intermediate alloys Cu-Zr and Cu-Mo, and pure silver ingots were mixed, with Zr: 0.1 wt%, Mo: 0.2 wt%, Ag: 0.1 wt%, and the balance being Cu. The mixture was melted in a vacuum induction melting furnace (after evacuating to 1 Pa, heated to 1350 °C at a heating rate of 8 °C / s and held for 15 minutes) and thoroughly homogenized (further held at 1300 °C for 30 minutes with 30 Hz electromagnetic stirring). The molten metal was then atomized into fine droplets using a high-pressure inert gas (such as argon), which rapidly solidified to form spherical powder, i.e., multi-component copper alloy powder.

[0052] S2, Functionalization modification of graphene oxide: GO was dispersed in deionized water by ultrasonic stirring at 200W for 0.5h, with a GO dispersion concentration of 1mg / mL; polyethyleneimine was added at an amount of 10% of the GO mass, and the solution was stirred and the pH value of the solution was adjusted to 8.5 to obtain a cationic GO dispersion.

[0053] S3, Electrostatic self-assembly and ball milling to construct core-shell structures: The multi-element copper alloy powder prepared in S1 was mixed with the cationic GO dispersion obtained in S2 at a mass ratio of 100:0.5 to obtain a mixed slurry. 0.05 wt% of the aminosilane coupling agent γ-aminopropyltriethoxysilane was added to the mixed slurry, followed by a process control agent (a mixture of anhydrous ethanol and glycerol at a volume ratio of 95:5), with the process control agent added at 1 vol% of the total powder mass. Then, a three-stage low-speed wet ball milling process was used to achieve uniform coating and structural optimization of GO. First stage: 100 rpm, ball-to-material ratio 9:1, ball milling time 2 hours; Second stage: 150 rpm, ball-to-material ratio 10:1, ball milling time 4 hours; Third stage: 100 rpm, ball-to-material ratio 9:1, ball milling time 2 hours, ball milling temperature 30℃; to obtain the ball-milled slurry.

[0054] S4, Spray drying and thermal reduction of composite powder: The ball-milled slurry is spray-dried; then, the dried powder is heat-treated in a reducing atmosphere to obtain the reduced core-shell structured composite powder; specifically, the spray drying inlet temperature is 180℃; the thermal reduction temperature is 450℃; the thermal reduction atmosphere and time are: argon / hydrogen mixture, hydrogen volume content is 5%, and the temperature is maintained for 1 hour.

[0055] S5, Densification by Spark Plasma Sintering: The reduced core-shell composite powder is loaded into a graphite mold and placed into the cavity of a spark plasma sintering equipment; sintering temperature: 900℃; sintering pressure: 40MPa; heating rate: 100℃ / min; holding time: 5min; vacuum degree: 5Pa; to obtain a sintered and dense composite material.

[0056] S6, Ion implantation of surface boron nitride gradient layer: S61, Pretreatment stage: The surface of the sintered and dense composite material is subjected to plasma cleaning using argon as the cleaning gas, plasma power of 300W, cleaning time of 15min, and target chamber vacuum of 1×10⁻⁶. -4 Pa; S62, Gradient Injection Stage 1: Using diborane and nitrogen as source gases, with a source gas flow ratio of diborane:nitrogen = 1:3, injection energy 5keV, and injection dose 1×10⁻⁶. 17 ions / cm 2 ; S63, Gradient Injection Second Stage: Maintaining the source gas flow rate ratio constant, increase the injection energy to 12 keV and the injection dose to 1.5 × 10⁻⁶. 18 ions / cm 2 ; S64, Gradient Injection Stage 3: Adjust the source gas flow ratio of diborane:nitrogen = 1:6, injection energy 18keV, injection dose 2×10⁻⁶. 17 ions / cm 2 The vacuum level in the target chamber was maintained at 0.1 × 10⁻⁶ throughout the entire process. -3 Pa; S65, In-situ annealing: After injection, in-situ annealing is performed under an argon protective atmosphere at an annealing temperature of 400℃, a holding time of 30min, and a heating rate of 4℃ / min. S66, Post-processing stage: Plasma polishing technology is used to finely treat the surface with a power of 180W and a processing time of 5 minutes to obtain a high-strength and high-conductivity composite conductor material for high-stability special cables.

[0057] The high-stability, high-strength, high-conductivity composite conductor material for high-stability special cables obtained in this embodiment has a BN gradient layer on its surface. The thickness of the BN gradient layer is about 50 nm, and its composition is distributed in a continuous gradient. The B content gradually decreases from the matrix to the surface, and the N content gradually increases. The BN gradient layer and the surface graphene network form a three-dimensional interconnected heat dissipation path.

[0058] The high-strength, high-conductivity composite conductor material for high-stability special cables in this embodiment forms a continuous composition gradient distribution with surface B:N=1:1.5, interface B:N=1:1.0, and matrix B:N=1:0.5.

[0059] This embodiment describes the application of high-strength, high-conductivity composite conductor materials for high-stability special cables in space cables.

[0060] A space cable is prepared from a high-strength, high-conductivity composite conductor material for high-stability special cables, as described in this embodiment. Example 3

[0061] A method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables includes the following steps: S1, Preparation of multi-component copper alloy powder: Preparation was achieved using gas atomization technology at a pressure of 8.0 MPa. Spherical powder of 15-45 μm was selected. Specifically, high-purity copper, intermediate alloys Cu-Zr and Cu-Mo, and pure silver ingots were mixed, with Zr: 0.5 wt%, Mo: 1.0 wt%, Ag: 0.5 wt%, and the balance being Cu. The mixture was melted in a vacuum induction melting furnace (after evacuating to 3 Pa, heated to 1450 °C at a heating rate of 12 °C / s and held for 30 minutes) and thoroughly homogenized (further held at 1400 °C for 60 minutes with 50 Hz electromagnetic stirring). The molten metal was then atomized into fine droplets by a high-pressure inert gas (such as argon), which rapidly solidified to form spherical powder, i.e., multi-component copper alloy powder.

[0062] S2, Functionalization modification of graphene oxide: GO was dispersed in deionized water by ultrasonic stirring at 500W for 2 hours. The concentration of GO dispersion was 3 mg / mL. Polyethyleneimine with an addition amount of 30% of the GO mass was added, and the solution was stirred and the pH value of the solution was adjusted to 10.0 to obtain a cationic GO dispersion.

[0063] S3, Electrostatic self-assembly and ball milling to construct core-shell structures: The multi-element copper alloy powder prepared in S1 was mixed with the cationic GO dispersion obtained in S2 at a mass ratio of 100:3.0 to obtain a mixed slurry. 0.1 wt% of the aminosilane coupling agent γ-aminopropyltriethoxysilane was added to the mixed slurry, followed by a process control agent (a mixture of anhydrous ethanol and glycerol at a volume ratio of 95:5), with the process control agent added at 3 vol% of the total powder mass. Then, a three-stage low-speed wet ball milling process was used to achieve uniform coating and structural optimization of GO. First stage: 150 rpm, ball-to-material ratio 9:1, ball milling time 2 hours; Second stage: 200 rpm, ball-to-material ratio 10:1, ball milling time 4 hours; Third stage: rotation speed 150 rpm, ball-to-material ratio 9:1, ball milling time 2 hours, ball milling temperature 35℃; to obtain the ball-milled slurry.

[0064] S4, Spray drying and thermal reduction of composite powder: The ball-milled slurry is spray-dried; then, the dried powder is heat-treated in a reducing atmosphere to obtain the reduced core-shell structured composite powder; specifically, the spray drying inlet temperature is 220℃; the thermal reduction temperature is 600℃; the thermal reduction atmosphere and time are: argon / hydrogen mixture, hydrogen volume content is 10%, and the temperature is maintained for 2 hours.

[0065] S5, Densification by Spark Plasma Sintering: The reduced core-shell composite powder is loaded into a graphite mold and placed into the cavity of a spark plasma sintering equipment; sintering temperature: 1000℃; sintering pressure: 60MPa; heating rate: 200℃ / min; holding time: 15min; vacuum degree: 5Pa; a dense sintered composite material is obtained.

[0066] S6, Ion implantation of surface boron nitride gradient layer: S61, Pretreatment stage: The surface of the sintered and dense composite material is subjected to plasma cleaning using argon as the cleaning gas, plasma power of 400W, cleaning time of 20min, and target chamber vacuum of 0.1×10⁻⁶. -4 Pa; S62, Gradient Injection Stage 1: Using diborane and nitrogen as source gases, with a source gas flow ratio of diborane:nitrogen = 1:5, injection energy 8keV, and injection dose 1×10⁻⁶. 17 ions / cm 2 ; S63, Gradient Injection Second Stage: Maintaining the source gas flow rate ratio constant, increase the injection energy to 15 keV and the injection dose to 1.5 × 10⁻⁶. 18 ions / cm 2 ; S64, Gradient Injection Stage 3: Adjust the source gas flow ratio of diborane:nitrogen = 1:8, injection energy 20keV, injection dose 2×10⁻⁶. 17 ions / cm 2 The vacuum level in the target chamber was maintained at 0.1 × 10⁻⁶ throughout the entire process. -3 Pa; S65, In-situ annealing: After injection, in-situ annealing is performed under an argon protective atmosphere at an annealing temperature of 450℃, a holding time of 60min, and a heating rate of 5℃ / min. S66, Post-processing stage: Plasma polishing technology is used to finely treat the surface with a power of 200W and a processing time of 4 minutes to obtain a high-strength and high-conductivity composite conductor material for high-stability special cables.

[0067] The high-stability, high-strength, high-conductivity composite conductor material for high-stability special cables obtained in this embodiment has a BN gradient layer on its surface. The thickness of the BN gradient layer is about 150 nm, and its composition is distributed in a continuous gradient. The B content gradually decreases from the matrix to the surface, and the N content gradually increases. The BN gradient layer and the surface graphene network form a three-dimensional interconnected heat dissipation path.

[0068] The high-strength, high-conductivity composite conductor material for high-stability special cables in this embodiment forms a continuous composition gradient distribution with surface B:N=1:1.5, interface B:N=1:1.0, and matrix B:N=1:0.5.

[0069] This embodiment describes the application of high-strength, high-conductivity composite conductor materials for high-stability special cables in space cables.

[0070] A space cable is prepared from a high-strength, high-conductivity composite conductor material for high-stability special cables, as described in this embodiment.

[0071] Comparative Example 1

[0072] This comparative example uses pure copper.

[0073] Comparative Example 2

[0074] This comparative example is the existing Gr / Cu, where Gr is graphene and Gr / Cu is graphene copper. The Gr / Cu preparation method adopts the method described in the existing technology "Microstructure evolution and mechanical / electrical property enhancement of graphene-copper composites via equal channel angular pressing processing." Journal of Materials Research and Technology. 39(2025), 9316-9329.

[0075] Comparative Example 3

[0076] The only difference between this comparative example and Example 1 is that in S3, the three-stage ball milling process is as follows: First stage: 80 rpm, ball-to-material ratio 7:1, ball milling time 2 hours; Second stage: 120 rpm, ball-to-material ratio 8:1, ball milling time 4 hours; Third stage: rotation speed 80 rpm, ball-to-material ratio 7:1, ball milling time 2 hours, ball milling temperature 45℃.

[0077] Comparative Example 4

[0078] The only difference between this comparative example and Example 1 is that in S3, the three-stage ball milling process is as follows: First stage: 200 rpm, ball-to-material ratio 10:1, ball milling time 2 hours; Second stage: 250 rpm, ball-to-material ratio 12:1, ball milling time 4 hours; Third stage: rotation speed 200 rpm, ball-to-material ratio 10:1, ball milling time 2 hours, ball milling temperature 35℃.

[0079] Comparative Example 5

[0080] The only difference between this comparative example and Example 1 is that only two-stage ion implantation is used in S6, that is, the third stage of gradient implantation in S64 is omitted.

[0081] Comparative Example 6

[0082] The only difference between this comparative example and Example 1 is that a fourth gradient injection stage is added after the third stage of gradient injection in S64. Specifically, in the fourth stage of gradient injection, the source gas flow rate ratio of the third stage is kept constant, the injection energy is increased to 25 keV, and the injection dose is 1.2 × 10⁻⁶. 18 ions / cm 2 .

[0083] The performance parameters of the embodiments and comparative examples of the present invention are shown in Table 1 below.

[0084] Table 1 Performance Parameters

[0085] It should be understood that, in order to simplify this disclosure and aid in understanding one or more of the various aspects of the invention, features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this method of disclosure should not be interpreted as reflecting an intention that the claimed invention requires more features than expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in fewer than all the features of the foregoingly disclosed embodiments. Therefore, the claims, following the detailed description, are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of the invention.

[0086] Although the invention has been described with reference to a limited number of embodiments, those skilled in the art will understand from the foregoing description that other embodiments are conceivable within the scope of the invention described herein. Furthermore, it should be noted that the language used in this specification has been chosen primarily for readability and instructional purposes, and not for the purpose of interpreting or limiting the subject matter of the invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the invention is illustrative and not restrictive, and the scope of the invention is defined by the appended claims.

[0087] 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 method for preparing a high-strength, high-conductivity composite conductor material for high-stability special cables, characterized in that, Includes the following steps: S1, Preparation of multi-element copper alloy powder: prepared by gas atomization technology, atomization gas pressure: 3.0-8.0 MPa; spherical powder of 15-45 μm was screened. S2, Functional modification of graphene oxide: GO was dispersed in deionized water by ultrasonic stirring, with a GO dispersion concentration of 1-3 mg / mL; polyethyleneimine was added at an amount of 10%-30% of the GO mass, and the solution was stirred and the pH value was adjusted to 8.5-10.0 to obtain a cationic GO dispersion. S3, Electrostatic self-assembly and ball milling to construct core-shell structures: The multi-element copper alloy powder prepared in S1 was mixed with the cationic GO dispersion obtained in S2 at a mass ratio of 100:(0.5-3.0) to obtain a mixed slurry. An aminosilane coupling agent, equivalent to 0.05-0.1 wt% of the mixed slurry, was added, followed by a process control agent, with the amount added being 1-3 vol% of the total powder mass. Then, a three-stage low-speed wet ball milling process was used to achieve uniform coating and structural optimization of GO. First stage: rotation speed 100-150rpm, ball-to-material ratio 8:1~9:1, ball milling time 2h; Second stage: rotation speed 150-200 rpm, ball-to-material ratio 9:1~10:1, ball milling time 4 hours; Third stage: rotation speed 100-150 rpm, ball-to-material ratio 8:1~9:1, ball milling time 2h, ball milling temperature ≤40℃; to obtain the ball-milled slurry; S4, Spray drying and thermal reduction of composite powder: The ball-milled slurry is spray-dried; then, the dried powder is heat-treated in a reducing atmosphere to obtain the reduced core-shell structured composite powder; S5, Densification by Spark Plasma Sintering: The reduced core-shell composite powder is loaded into a graphite mold and placed into the cavity of a spark plasma sintering equipment; sintering temperature: 900-1000℃; sintering pressure: 40-60MPa; heating rate: 100-200℃ / min; holding time: 5-15min; vacuum degree: ≤10Pa; a dense sintered composite material is obtained. S6, Ion implantation of surface boron nitride gradient layer: S61, Pretreatment stage: The surface of the sintered and dense composite material is subjected to plasma cleaning using argon as the cleaning gas, plasma power of 300-400W, cleaning time of 15-20min, and target chamber vacuum degree ≤5×10 -4 Pa; S62, Gradient Injection Stage 1: Using diborane and nitrogen as source gases, the source gas flow ratio of diborane:nitrogen is 1:3-1:5, the injection energy is 5-8 keV, and the injection dose is 5×10⁻⁶. 16 -1×10 17 ions / cm 2 ; S63, Gradient Injection Second Stage: Maintaining the source gas flow rate ratio constant, increase the injection energy to 12-15 keV, and the injection dose is 1×10⁻⁶. 17 -1.5×10 18 ions / cm 2 ; S64, Gradient Injection Stage 3: Adjust the source gas flow rate ratio of diborane:nitrogen to 1:6-1:8, injection energy 18-20 keV, injection dose 1.5 × 10⁻⁶. 17 -2×10 17 ions / cm 2 The vacuum level in the target chamber was maintained at ≤1×10 throughout the entire process. -3 Pa; S65, in-situ annealing: After injection, in-situ annealing is performed under an argon protective atmosphere at an annealing temperature of 400-450℃, a holding time of 30-60 min, and a heating rate of 4-5℃ / min. S66, Post-processing stage: The surface is finely treated using plasma polishing technology, with a power of 180-200W and a processing time of 4-5 minutes.

2. The preparation method according to claim 1, characterized in that, In S1, high-purity copper, intermediate alloys Cu-Zr and Cu-Mo, and pure silver ingots are mixed together, with Zr: 0.1-0.5 wt%, Mo: 0.2-1.0 wt%, Ag: 0.1-0.5 wt%, and the balance being Cu.

3. The preparation method according to claim 1, characterized in that, In S2, the ultrasonic treatment power and time are 200-500W for 0.5-2 hours.

4. The preparation method according to claim 1, characterized in that, In S3, the aminosilane coupling agent includes γ-aminopropyltriethoxysilane; the process control agent is a mixture of anhydrous ethanol and glycerol in a volume ratio of 95:

5.

5. The preparation method according to claim 1, characterized in that, In S4, the spray drying inlet temperature is 180-220℃; the thermal reduction temperature is 450-600℃; the thermal reduction atmosphere and time are: argon / hydrogen mixture, hydrogen volume content is 5-10%, and the temperature is maintained for 1-2 hours.

6. The high-stability, high-strength, high-conductivity composite conductor material for special cables obtained by the preparation method according to any one of claims 1 to 5, characterized in that, The composite conductor material has a BN gradient layer on its surface, with a thickness of 50-150 nm and a continuous gradient distribution of composition. The B content gradually decreases from the substrate to the surface, while the N content gradually increases. The BN gradient layer and the surface graphene network form a three-dimensional interconnected heat dissipation pathway.

7. The high-strength, high-conductivity composite conductor material for high-stability special cables according to claim 6, characterized in that, The composite conductor material forms a continuous compositional gradient distribution with surface B:N=1:1.5, interface B:N=1:1.0, and matrix B:N=1:0.

5.

8. The high-strength, high-conductivity composite conductor material for high-stability special cables according to claim 6, characterized in that, Under extreme temperature cycling from -150℃ to +200℃, the conductivity retention rate is >98%, the strength retention rate is >99%, the conductivity decay rate after 500 krad radiation is <3%, and there is no surface corrosion after simulated atomic oxygen exposure.

9. The application of the high-strength, high-conductivity composite conductor material for high-stability special cables according to claim 6 in space cables.

10. A space cable, made from the high-strength, high-conductivity composite conductor material for high-stability special cables as described in claim 6.

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