High-performance copper alloy wire and preparation process thereof
By combining rare earth-modified carbon nanotubes with Cu-Hf and Cu-Ce master alloys and depositing a Pd-Co gradient transition layer, the problems of synergistic improvement of strength and conductivity, as well as heat resistance and corrosion resistance of copper alloy wires, were solved, and the preparation of high-performance copper alloy wires was realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI JINYE DATONG TECH CO LTD
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-02
Smart Images
Figure CN122136094A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of copper alloy materials technology, specifically to a high-performance copper alloy wire and its preparation process. Background Technology
[0002] Copper and copper alloy wires are widely used in power transmission, rail transportation, new energy vehicles, aerospace and other fields due to their excellent electrical conductivity, thermal conductivity and processing performance.
[0003] Currently, the copper alloy wires commonly used in industry are mainly Cu-Cr-Zr and Cu-Ni-Si alloys. Although they can meet basic usage requirements to a certain extent, it is difficult to improve their strength and conductivity in a coordinated manner. Increasing the strength often leads to a significant decrease in conductivity, which cannot meet the dual performance requirements of high-end scenarios. Carbon nanotubes possess ultra-high strength and elastic modulus, and can act as a dispersed reinforcing phase in copper matrices, effectively hindering dislocation movement and refining grains. Simultaneously, they bear most of the stress under tensile and fatigue loads, significantly improving the tensile strength, yield strength, creep resistance, and fatigue life of copper alloys. Furthermore, carbon nanotubes themselves have excellent electrical conductivity; when uniformly dispersed in the matrix, they can form a continuous conductive network, reducing electron scattering by grain boundaries and defects. This could potentially improve conductivity while enhancing strength. However, carbon nanotubes have a large specific surface area and high surface energy, making them prone to agglomeration and clustering. Moreover, carbon nanotubes exhibit extremely poor wettability with copper, resulting in weak interfacial bonding. Under external loads or high temperatures, they are susceptible to interfacial debonding and separation, failing to effectively transfer loads and electrons, thus hindering the reinforcing and conductive effects of carbon nanotubes.
[0004] In addition, copper alloy wires have insufficient heat resistance and are prone to grain coarsening and performance softening under high temperature conditions, affecting long-term service reliability. Moreover, the surface protection effect is poor. The protective layer prepared by traditional electroplating and hot-dip plating processes has defects such as weak adhesion, easy peeling, and pinholes, which makes the wires easy to oxidize and have poor corrosion resistance.
[0005] Therefore, there is a need to propose a high-performance copper alloy wire with high conductivity, tensile strength, heat resistance and corrosion resistance, as well as its preparation process, in order to extend its service life. Summary of the Invention
[0006] To address the shortcomings of existing technologies, the present invention aims to provide a high-performance copper alloy wire and its preparation process.
[0007] This invention provides a process for preparing high-performance copper alloy wires, comprising the following steps: S1: Preparation of rare earth modified carbon nanotubes After carboxylation, multi-walled carbon nanotubes are dispersed in anhydrous ethanol and then mixed with a rare earth citric acid coupling agent solution to react and obtain rare earth modified carbon nanotubes. S2: Preparation of base copper alloy wire S2.1: Add high-purity electrolytic copper into a vacuum induction melting furnace, evacuate the furnace, fill it with high-purity argon, and then heat it at 1300-1400℃ until the copper is completely melted. Then add Cu-Cr master alloy and Cu-Zr master alloy, stir and melt for 20-30 minutes to obtain the alloy melt. S2.2: Using high-purity argon gas at 3-5 MPa as the atomizing medium, the above alloy melt flow is crushed into droplets, and then rapidly condensed into powder in an atomizing tower protected by nitrogen to obtain pre-alloyed powder. S2.3: Place the above rare earth modified carbon nanotubes, the above pre-alloyed powder, Cu-Hf master alloy and Cu-Ce master alloy into a ball mill jar and ball mill for 3-4 hours under argon protection to obtain composite powder; S2.4: Add the above composite powder and high-purity electrolytic copper into a vacuum induction melting furnace, evacuate the furnace, fill it with high-purity argon gas for protection, melt at 1200-1250℃ for 1-1.5h, and then cast it into an ingot to obtain an alloy ingot. S2.5: Under argon protection, the above alloy ingot is annealed at 900-950℃ for 2-4 hours, then hot rolled and low temperature drawn, and then aged at 390-420℃ for 1-2 hours, and then aged at 450-480℃ for 2-3 hours. After cooling, the base copper alloy wire is obtained. S3: Preparation of copper alloy wires After pretreatment of the above-mentioned copper alloy base wire, a Pd-Co gradient transition layer is first deposited, followed by a pure Pd layer to form a corrosion-resistant protective layer, thus obtaining a copper alloy conductor.
[0008] Furthermore, S1 includes the following steps: S1.1: Add multi-walled carbon nanotubes to the acidification solution at a ratio of 1g:(10-12)mL, disperse by ultrasonication for 30-40min, then heat and reflux at 70-80℃ for 3-4h, cool, filter, wash until neutral and vacuum dry to obtain carboxylated carbon nanotubes; S1.2: Add citric acid monohydrate to deionized water at a ratio of 1g:(15-25)mL, heat and stir at 50-60℃ to dissolve, then add lanthanum nitrate and cerium nitrate, continue stirring to dissolve, adjust the pH to 5-6 with dilute ammonia, and heat and stir at 60-70℃ for 1-2 hours to obtain rare earth citric acid coupling agent solution. S1.3: Under nitrogen protection, the above carboxylated carbon nanotubes were added to anhydrous ethanol at a ratio of 1g:(80-100)mL, and ultrasonically dispersed for 30-40min to obtain a carboxylated carbon nanotube dispersion. Then, the above rare earth citric acid coupling agent solution was added, and the mixture was heated and stirred at 60-70℃ for 4-5h. After cooling, the mixture was filtered, washed, and vacuum dried to obtain rare earth modified carbon nanotubes.
[0009] Furthermore, S3 includes the following steps: S3.1: Immerse the base copper alloy wire obtained in step S2.5 in anhydrous ethanol, ultrasonically clean for 3-5 minutes, then ultrasonically clean with deionized water for 1-3 minutes, and dry with nitrogen to obtain the pretreated wire. S3.2: The pretreated wire is fed into the ALD reaction chamber, preheated to 180-200℃ and kept at that temperature for 10-20 min, then treated with hydrogen plasma for 3-5 min. The vacuum degree of the ALD reaction chamber is then adjusted to 5-10 Pa, and high-purity argon gas with a flow rate of 50-100 sccm is introduced. Di(hexafluoroacetylacetone)palladium is used as the palladium precursor, di(acetylacetone)cobalt is used as the cobalt precursor, and high-purity hydrogen is used as the reaction gas. A general pulse timing is set, and a Pd-Co gradient transition layer is deposited on the surface of the pretreated wire to obtain a single-layer wire. S3.3: Then stop the introduction of cobalt di(acetylacetone) and introduce only palladium di(hexafluoroacetylacetone) and high-purity hydrogen. Keep the general pulse timing unchanged and deposit a pure Pd layer on the surface of the Pd-Co gradient transition layer of the single-layer wire. The total cycle is 35 cycles. Then, it is naturally cooled under argon purging to form a corrosion-resistant protective layer and obtain a copper alloy wire.
[0010] Furthermore, the acidification solution is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3.
[0011] Furthermore, the molar ratio of citric acid monohydrate, lanthanum nitrate, and cerium nitrate is (2.8-3):(0.8-1):1.
[0012] Furthermore, the volume ratio of the rare earth citric acid coupling agent solution to the carboxylated carbon nanotube dispersion is 1:(4-5).
[0013] Furthermore, by mass percentage, the base copper alloy wire comprises: 0.4-0.6% Cr, 0.05-0.2% Zr, 0.05-0.06% Hf, 0.01-0.03% Ce, 0.4-0.5% rare earth modified carbon nanotubes, with the balance being Cu.
[0014] Furthermore, the general pulse timing set in step S3.2 is as follows: precursor pulse 0.8s, purge 2.5s, hydrogen reaction pulse 1.5s, purge 2.5s.
[0015] Furthermore, the total number of cycles for depositing the Pd-Co gradient transition layer was 22. Specifically, the first stage had a 1:2 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and was deposited for 7 cycles; the second stage had a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and was deposited for 8 cycles; and the third stage had a 2:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and was deposited for 7 cycles.
[0016] A high-performance copper alloy wire, which is prepared by the preparation process of a high-performance copper alloy wire as described in any one of the above claims.
[0017] The present invention has the following advantages: 1. In this invention, by first activating carbon nanotubes with carboxylation and then modifying them with rare earth citric acid coupling agents, the wettability and compatibility of carbon nanotubes with the copper matrix can be effectively improved, thereby increasing the dispersibility of carbon nanotubes. The uniformly dispersed rare earth modified carbon nanotubes can form a continuous conductive network in the copper matrix, serving as an efficient electron transport channel to compensate for the electron transport loss of the copper matrix itself. At the same time, the lanthanum and cerium introduced during modification can purify the grain boundaries and reduce electron scattering at the grain boundaries, thereby effectively improving the conductivity of the matrix copper alloy wire. In addition, the uniformly dispersed rare earth modified carbon nanotubes, as a hard dispersed phase, can effectively hinder dislocation movement and suppress plastic deformation. At the same time, as a heterogeneous nucleation core during the solidification of copper alloy, they refine the matrix grains, thereby effectively improving the tensile strength of the matrix copper alloy wire.
[0018] 2. In this invention, by mixing Cu-Hf master alloy and Cu-Ce master alloy with pre-alloyed powder and rare earth modified carbon nanotubes and ball milling, followed by vacuum melting, casting, annealing, hot rolling, low-temperature drawing and aging treatment to produce a base copper alloy wire, Hf can form a highly stable Cu-Hf intermetallic compound in copper, strongly pinning grain boundaries and dislocations, preventing high-temperature grain growth. Ce can replace and purify harmful impurities at grain boundaries, reduce the grain boundary diffusion rate, and provide stable attachment sites for Hf precipitates. This dual inhibition of high-temperature grain coarsening significantly increases the recrystallization temperature of the base copper alloy wire. At the same time, the Hf precipitates strongly hinder high-temperature dislocation slip, and Ce strengthens grain boundaries, inhibiting grain boundary slip and diffusion creep. The two form a composite dispersed strengthening phase, making the base copper alloy wire less prone to deformation under long-term high-temperature load, thereby achieving a synergistic effect of improving the heat resistance of the base copper alloy wire.
[0019] 3. In this invention, a three-stage cycle is used on the surface of the copper alloy wire substrate to achieve a continuous compositional gradient from Co-rich to Pd-rich. When depositing the Pd-Co gradient transition layer on the surface of the copper alloy wire substrate, the Co layer first achieves interface anchoring due to the higher lattice matching degree between Co and the copper substrate. Then, the Pd ratio is gradually increased to achieve a smooth transition, eliminating lattice mismatch and internal stress between the copper substrate, the transition layer, and the pure Pd layer. This avoids film cracking, warping, and peeling caused by abrupt compositional changes, thereby effectively improving the film adhesion. Subsequently, pure Pd is deposited on the gradient layer to form a continuous, dense, and inert noble metal conductive protective layer, thereby effectively improving the corrosion resistance of the copper alloy wire. Attached Figure Description
[0020] Figure 1 This is a flowchart illustrating the manufacturing process of the high-performance copper alloy wire used in an embodiment of the present invention. Detailed Implementation
[0021] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of this invention.
[0022] Example 1: A manufacturing process for a high-performance copper alloy wire, as follows: Figure 1 As shown, it includes the following steps: S1: Preparation of rare earth modified carbon nanotubes S1.1: Add multi-walled carbon nanotubes to the acidification solution at a ratio of 1g:10mL, disperse ultrasonically for 30min, then heat and reflux at 70℃ for 3h, cool, filter, wash until neutral and vacuum dry to obtain carboxylated carbon nanotubes. The acidification solution is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3. S1.2: Citric acid monohydrate was added to deionized water at a ratio of 1g:15mL, heated and stirred at 50℃ to dissolve, then lanthanum nitrate and cerium nitrate were added, and the mixture was stirred and dissolved again. The pH was adjusted to 5 with dilute ammonia, and the mixture was heated and stirred at 60℃ for 1h to obtain a rare earth citric acid coupling agent solution. The molar ratio of citric acid monohydrate, lanthanum nitrate and cerium nitrate was 2.8:0.8:1. S1.3: Under nitrogen protection, the above carboxylated carbon nanotubes were added to anhydrous ethanol at a ratio of 1g:80mL and ultrasonically dispersed for 30min to obtain a carboxylated carbon nanotube dispersion. Then, the above rare earth citric acid coupling agent solution was added, and the mixture was heated and stirred at 60℃ for 4h. After cooling, the mixture was filtered, washed, and vacuum dried to obtain rare earth modified carbon nanotubes. The volume ratio of the rare earth citric acid coupling agent solution to the carboxylated carbon nanotube dispersion was 1:4. S2: Preparation of base copper alloy wire S2.1: High-purity electrolytic copper is added to a vacuum induction melting furnace, vacuum is drawn and high-purity argon is introduced, and then the furnace is heated to 1300℃ until the copper is completely melted. Then Cu-Cr master alloy and Cu-Zr master alloy are added, and the furnace is stirred and melted for 20 minutes to obtain the alloy melt. S2.2: Using 3MPa high-purity argon gas as the atomizing medium, the above alloy melt flow is crushed into droplets, and then rapidly condensed into powder in a nitrogen-protected atomizing tower to obtain pre-alloyed powder; S2.3: The rare earth modified carbon nanotubes obtained in step S1.3, the above pre-alloyed powder, Cu-Hf master alloy and Cu-Ce master alloy are placed in a ball mill jar and ball-milled for 3 hours under argon protection to obtain composite powder. S2.4: The above composite powder and high-purity electrolytic copper are added to a vacuum induction melting furnace, vacuumed and then filled with high-purity argon for protection. The furnace is melted at 1200℃ for 1 hour and then cast into an ingot to obtain an alloy ingot. S2.5: Under argon protection, the above alloy ingot is annealed at 900℃ for 2 hours, hot rolled, and then drawn at low temperature. It is then aged at 390℃ for 1 hour and then aged at 450℃ for 2 hours. After cooling, a base copper alloy wire is obtained. The base copper alloy wire, by mass percentage, includes: 0.4% Cr, 0.05% Zr, 0.05% Hf, 0.01% Ce, 0.4% rare earth modified carbon nanotubes, and the balance is Cu. S3: Preparation of copper alloy wires S3.1: Immerse the base copper alloy wire obtained in step S2.5 in anhydrous ethanol, ultrasonically clean for 3 minutes, then ultrasonically clean with deionized water for 1 minute, and dry with nitrogen to obtain the pretreated wire. S3.2: The pretreated wire is fed into the ALD reaction chamber, preheated to 180°C and held for 10 minutes, then treated with hydrogen plasma for 3 minutes. The vacuum level of the ALD reaction chamber is then adjusted to 5 Pa, and high-purity argon gas at a flow rate of 50 sccm is introduced. Using bis(hexafluoroacetylacetone)palladium as the palladium precursor, bis(acetylacetone)cobalt as the cobalt precursor, and high-purity hydrogen as the reactant gas, a universal pulse timing sequence is set to deposit a Pd-Co gradient transition layer on the surface of the pretreated wire, resulting in a single-layer wire. The general pulse timing is as follows: precursor pulse 0.8s, purge 2.5s, hydrogen reaction pulse 1.5s, purge 2.5s, and the total number of cycles for depositing the Pd-Co gradient transition layer is 22. Specifically, the first stage has a 1:2 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles; the second stage has a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 8 cycles; and the third stage has a 2:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles. S3.3: Then stop the introduction of cobalt di(acetylacetone) and introduce only palladium di(hexafluoroacetylacetone) and high-purity hydrogen. Keep the general pulse timing unchanged and deposit a pure Pd layer on the surface of the Pd-Co gradient transition layer of the single-layer wire. The total cycle is 35 cycles. Then, it is naturally cooled under argon purging to form a corrosion-resistant protective layer and obtain a copper alloy wire.
[0023] Example 2: A manufacturing process for a high-performance copper alloy wire, as follows: Figure 1 As shown, it includes the following steps: S1: Preparation of rare earth modified carbon nanotubes S1.1: Add multi-walled carbon nanotubes to the acidification solution at a ratio of 1g:11mL, disperse ultrasonically for 35min, then heat and reflux at 75℃ for 3.5h, cool, filter, wash until neutral and vacuum dry to obtain carboxylated carbon nanotubes. The acidification solution is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3. S1.2: Citric acid monohydrate was added to deionized water at a ratio of 1g:20mL, heated and stirred at 55℃ to dissolve, then lanthanum nitrate and cerium nitrate were added, and the mixture was stirred and dissolved again. The pH was adjusted to 5.5 with dilute ammonia, and the mixture was heated and stirred at 65℃ for 1.5h to obtain a rare earth citric acid coupling agent solution, wherein the molar ratio of citric acid monohydrate, lanthanum nitrate and cerium nitrate was 2.9:0.9:1. S1.3: Under nitrogen protection, the above carboxylated carbon nanotubes were added to anhydrous ethanol at a ratio of 1 g: 90 mL and ultrasonically dispersed for 35 min to obtain a carboxylated carbon nanotube dispersion. Then, the above rare earth citric acid coupling agent solution was added, and the mixture was heated and stirred at 65 °C for 4.5 h. After cooling, the mixture was filtered, washed, and vacuum dried to obtain rare earth modified carbon nanotubes. The volume ratio of the rare earth citric acid coupling agent solution to the carboxylated carbon nanotube dispersion was 1:4.5. S2: Preparation of base copper alloy wire S2.1: High-purity electrolytic copper is added to a vacuum induction melting furnace, vacuum is drawn and high-purity argon is introduced, and then the furnace is heated to 1350℃ until the copper is completely melted. Then Cu-Cr master alloy and Cu-Zr master alloy are added, and the furnace is stirred and melted for 25 minutes to obtain the alloy melt. S2.2: Using 4MPa high-purity argon gas as the atomizing medium, the above alloy melt flow is crushed into droplets, and then rapidly condensed into powder in a nitrogen-protected atomization tower to obtain pre-alloyed powder; S2.3: The rare earth modified carbon nanotubes obtained in step S1.3, the above pre-alloyed powder, Cu-Hf master alloy and Cu-Ce master alloy are placed in a ball mill jar and ball-milled for 3.5 hours under argon protection to obtain composite powder. S2.4: The above composite powder and high-purity electrolytic copper are added to a vacuum induction melting furnace, vacuumed and then filled with high-purity argon for protection. The furnace is melted at 1225°C for 1.2 hours and then cast into an ingot to obtain an alloy ingot. S2.5: Under argon protection, the above alloy ingot is annealed at 925℃ for 3 hours, followed by hot rolling and low-temperature drawing. Then, it is aged at 405℃ for 1.5 hours and then aged at 465℃ for 2.5 hours. After cooling, a base copper alloy wire is obtained. The base copper alloy wire, by mass percentage, includes: 0.5% Cr, 0.12% Zr, 0.055% Hf, 0.02% Ce, 0.45% rare earth modified carbon nanotubes, and the balance is Cu. S3: Preparation of copper alloy wires S3.1: Immerse the base copper alloy wire obtained in step S2.5 in anhydrous ethanol, ultrasonically clean for 4 min, then ultrasonically clean with deionized water for 2 min, and dry with nitrogen to obtain the pretreated wire. S3.2: The pretreated wire is fed into the ALD reaction chamber, preheated to 190℃ and held for 15 min, then treated with hydrogen plasma for 4 min. The vacuum level of the ALD reaction chamber is then adjusted to 7.5 Pa, and high-purity argon gas at a flow rate of 75 sccm is introduced. Using bis(hexafluoroacetylacetone)palladium as the palladium precursor, bis(acetylacetone)cobalt as the cobalt precursor, and high-purity hydrogen as the reactant gas, a universal pulse timing sequence is set to deposit a Pd-Co gradient transition layer on the surface of the pretreated wire, resulting in a single-layer wire. The general pulse timing is as follows: precursor pulse 0.8s, purge 2.5s, hydrogen reaction pulse 1.5s, purge 2.5s, and the total number of cycles for depositing the Pd-Co gradient transition layer is 22. Specifically, the first stage has a 1:2 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles; the second stage has a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 8 cycles; and the third stage has a 2:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles. S3.3: Then stop the introduction of cobalt di(acetylacetone) and introduce only palladium di(hexafluoroacetylacetone) and high-purity hydrogen. Keep the general pulse timing unchanged and deposit a pure Pd layer on the surface of the Pd-Co gradient transition layer of the single-layer wire. The total cycle is 35 cycles. Then, it is naturally cooled under argon purging to form a corrosion-resistant protective layer and obtain a copper alloy wire.
[0024] Example 3: A manufacturing process for a high-performance copper alloy wire, as follows: Figure 1 As shown, it includes the following steps: S1: Preparation of rare earth modified carbon nanotubes S1.1: Add multi-walled carbon nanotubes to the acidification solution at a ratio of 1g:12mL, disperse ultrasonically for 40min, then heat and reflux at 80℃ for 4h, cool, filter, wash until neutral and vacuum dry to obtain carboxylated carbon nanotubes. The acidification solution is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:3. S1.2: Citric acid monohydrate was added to deionized water at a ratio of 1g:25mL, heated and stirred at 60℃ to dissolve, then lanthanum nitrate and cerium nitrate were added, and stirred and dissolved again. The pH was adjusted to 6 with dilute ammonia, and the mixture was heated and stirred at 70℃ for 2 hours to obtain a rare earth citric acid coupling agent solution, wherein the molar ratio of citric acid monohydrate, lanthanum nitrate and cerium nitrate was 3:1:1. S1.3: Under nitrogen protection, the above carboxylated carbon nanotubes were added to anhydrous ethanol at a ratio of 1g:100mL and ultrasonically dispersed for 40min to obtain a carboxylated carbon nanotube dispersion. Then, the above rare earth citric acid coupling agent solution was added, and the mixture was heated and stirred at 70℃ for 5h. After cooling, the mixture was filtered, washed, and vacuum dried to obtain rare earth modified carbon nanotubes. The volume ratio of the rare earth citric acid coupling agent solution to the carboxylated carbon nanotube dispersion was 1:5. S2: Preparation of base copper alloy wire S2.1: High-purity electrolytic copper is added to a vacuum induction melting furnace, vacuum is drawn and high-purity argon is introduced, and then the furnace is heated to 1400℃ until the copper is completely melted. Then Cu-Cr master alloy and Cu-Zr master alloy are added, and the furnace is stirred and melted for 30 minutes to obtain the alloy melt. S2.2: Using 5MPa high-purity argon gas as the atomizing medium, the above alloy melt flow is crushed into droplets, and then rapidly condensed into powder in a nitrogen-protected atomizing tower to obtain pre-alloyed powder; S2.3: The rare earth modified carbon nanotubes obtained in step S1.3, the above-mentioned pre-alloyed powder, Cu-Hf master alloy and Cu-Ce master alloy are placed in a ball mill jar and ball-milled for 4 hours under argon protection to obtain composite powder. S2.4: The above composite powder and high-purity electrolytic copper are added to a vacuum induction melting furnace, vacuumed and then filled with high-purity argon for protection. The furnace is melted at 1250°C for 1.5 hours and then cast into an ingot to obtain an alloy ingot. S2.5: Under argon protection, the above alloy ingot is annealed at 950℃ for 4 hours, hot rolled, and then drawn at low temperature. It is then aged at 420℃ for 2 hours and then aged at 480℃ for 3 hours. After cooling, a base copper alloy wire is obtained. The base copper alloy wire, by mass percentage, includes: 0.6% Cr, 0.2% Zr, 0.06% Hf, 0.03% Ce, 0.5% rare earth modified carbon nanotubes, and the balance is Cu. S3: Preparation of copper alloy wires S3.1: Immerse the base copper alloy wire obtained in step S2.5 in anhydrous ethanol, ultrasonically clean for 5 minutes, then ultrasonically clean with deionized water for 3 minutes, and dry with nitrogen to obtain the pretreated wire. S3.2: The pretreated wire is fed into the ALD reaction chamber, preheated to 200℃ and held for 20 min, then treated with hydrogen plasma for 5 min. The vacuum level of the ALD reaction chamber is then adjusted to 10 Pa, and high-purity argon gas at a flow rate of 100 sccm is introduced. Using bis(hexafluoroacetylacetone)palladium as the palladium precursor, bis(acetylacetone)cobalt as the cobalt precursor, and high-purity hydrogen as the reactant gas, a universal pulse timing sequence is set to deposit a Pd-Co gradient transition layer on the surface of the pretreated wire, resulting in a single-layer wire. The general pulse timing is as follows: precursor pulse 0.8s, purge 2.5s, hydrogen reaction pulse 1.5s, purge 2.5s, and the total number of cycles for depositing the Pd-Co gradient transition layer is 22. Specifically, the first stage has a 1:2 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles; the second stage has a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 8 cycles; and the third stage has a 2:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt and a deposition cycle of 7 cycles. S3.3: Then stop the introduction of cobalt di(acetylacetone) and introduce only palladium di(hexafluoroacetylacetone) and high-purity hydrogen. Keep the general pulse timing unchanged and deposit a pure Pd layer on the surface of the Pd-Co gradient transition layer of the single-layer wire. The total cycle is 35 cycles. Then, it is naturally cooled under argon purging to form a corrosion-resistant protective layer and obtain a copper alloy wire.
[0025] Comparative Example 1 differs from Example 1 in that the rare earth modified carbon nanotubes in step S2.3 are removed.
[0026] Comparative Example 2 differs from Example 1 in that the rare earth modified carbon nanotubes in step S2.3 are replaced with an equal amount of carboxylated carbon nanotubes.
[0027] Comparative Example 3 differs from Example 1 in that the composition of the base copper alloy wire obtained in step S2 is adjusted to: 0.4wt%Cr, 0.05wt%Zr, 0.06wt%Hf, 0.4wt%rare earth modified carbon nanotubes, with the balance being Cu.
[0028] Comparative Example 4 differs from Example 1 in that the composition of the base copper alloy wire obtained in step S2 is adjusted to: 0.4wt%Cr, 0.05wt%Zr, 0.06wt%Ce, 0.4wt%rare earth modified carbon nanotubes, with the balance being Cu.
[0029] Comparative Example 5 differs from Example 1 in that the composition of the base copper alloy wire obtained in step S2 is adjusted to: 0.4wt%Cr, 0.05wt%Zr, 0.4wt% rare earth modified carbon nanotubes, with the balance being Cu.
[0030] Comparative Example 6 differs from Example 1 in that a pure Pd layer is directly deposited on the surface of the pretreated wire obtained in step S3.1.
[0031] Comparative Example 7 differs from Example 1 in that the surface of the pretreated wire obtained in step S3.1 is deposited using only a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt for 22 cycles, and then a pure Pd layer is deposited according to the subsequent steps.
[0032] Test example: Test 1: The conductivity of the base copper alloy wires prepared in Examples 1-3 and Comparative Examples 1-2 was tested using an eddy current conductivity meter. The test was repeated 3 times and the average value was taken. The results are shown in Table 1.
[0033] Table 1: Conductivity Test Results of Copper Alloy Wire
[0034] Test 2: The tensile strength of the base copper alloy wires prepared in Examples 1-3 and Comparative Examples 1-2 was tested using an electronic universal testing machine. The test was repeated 3 times, and the average value was taken. The results are shown in Table 2.
[0035] Table 2: Tensile Strength Test Results of Copper Alloy Wire
[0036] As shown in Tables 1 and 2, in Comparative Example 1, without the addition of rare earth modified carbon nanotubes, the conductivity and tensile strength of the prepared copper alloy wire matrix were lower than those of Example 1. In Comparative Example 2, when carboxylated carbon nanotubes were directly added, the carboxylated carbon nanotubes agglomerated in the matrix, hindering electron movement, resulting in a lower conductivity than that of Comparative Example 1, which had a purer matrix. However, even if the carboxylated carbon nanotubes agglomerated, they still physically blocked the dislocation movement of the copper alloy matrix, thereby relatively increasing its tensile strength, resulting in a higher tensile strength than that of Comparative Example 1. Nevertheless, the conductivity and tensile strength of the copper alloy wire matrix prepared in Comparative Example 2 were still lower than those of Example 1. It can be seen that by first activating the carbon nanotubes by carboxylation and then modifying them with rare earth citric acid coupling agents, the dispersibility of carbon nanotubes can be effectively improved, thereby enhancing the conductivity and tensile strength of the copper alloy wire matrix.
[0037] Test 3: The tensile strength retention rate of the base copper alloy wires prepared in Examples 1-3 and Comparative Examples 3-5 at 300℃ and 100h was tested using an electronic universal testing machine. The test was repeated 3 times and the average value was taken. The results are shown in Table 3.
[0038] Table 3: Test results of tensile strength retention rate of copper alloy base wire
[0039] As shown in Table 3, the tensile strength retention rate of the matrix copper alloy wire prepared in Comparative Example 5 without the addition of Hf and Ce elements was significantly lower than that in Example 1. Although the tensile strength retention rate of the matrix copper alloy wire prepared in Comparative Examples 3 and 4 with only the addition of Hf or Ce elements was higher than that in Comparative Example 5, it was still lower than that in Example 1. It can be seen that by mixing Cu-Hf master alloy and Cu-Ce master alloy with pre-alloyed powder and rare earth modified carbon nanotubes, ball milling, and then performing vacuum melting, casting, annealing, hot rolling, low temperature drawing and aging treatment to prepare matrix copper alloy wire, Hf and Ce can form a composite dispersed strengthening phase, making the matrix copper alloy wire less prone to deformation under long-term high temperature load, thereby achieving the effect of synergistically improving the heat resistance of the matrix copper alloy wire.
[0040] Test 4: Referring to GB / T 5270-2024, the copper alloy wires prepared in Examples 1-3 and Comparative Examples 6-7 were subjected to bending tests. The core shaft with a diameter of Φ5mm was repeatedly bent 180°. The number of bends when the film layer first cracked was counted. The test was repeated 3 times and the average value was taken. The results are shown in Table 4.
[0041] Table 4: Test results of bending count at the first cracking of the copper alloy conductor film layer
[0042] Test 5: Referring to GB / T 10125-2021, the copper alloy wires prepared in Examples 1-3 and Comparative Examples 6-7 were subjected to a neutral salt spray test with 5% NaCl solution at a temperature of 35°C. The time when the first pitting / bulging appeared on the surface was recorded as the failure time. The test was repeated 3 times and the average value was taken. The results are shown in Table 5.
[0043] Table 5: Test Results of Surface Failure Time for Copper Alloy Conductors
[0044] As shown in Tables 4 and 5, in Comparative Example 6, when a pure Pd layer was deposited directly on the surface of the pretreated wire, the number of bending cycles during film cracking of the copper alloy conductor was less than that in Example 1. Furthermore, after a neutral salt spray test, its surface failure time was also lower than that in Example 1. In Comparative Example 7, when a pure Pd layer was deposited on the surface of the pretreated wire using only a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt for 22 cycles, the number of bending cycles during film cracking of the copper alloy conductor was greater than that in Comparative Example 6 but still less than that in Example 1. Furthermore, after a neutral salt spray test, its surface failure time was higher than that in Comparative Example 6 but still lower than that in Example 1. Example 1 illustrates that by employing a low-temperature atomic layer deposition process, a three-stage cycle is used on the surface of a copper alloy substrate wire to achieve a continuous compositional gradient from Co-rich to Pd-rich. This allows for a smooth transition when depositing a Pd-Co gradient transition layer on the copper alloy substrate wire surface, eliminating lattice mismatch and internal stress between the copper substrate, transition layer, and pure Pd layer. This prevents film cracking, warping, and peeling caused by abrupt compositional changes, thereby effectively improving film adhesion. Subsequently, pure Pd is deposited on the gradient layer to form a continuous, dense, and inert noble metal conductive protective layer, thus effectively improving the corrosion resistance of the copper alloy wire.
[0045] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.
Claims
1. A manufacturing process for high-performance copper alloy wires, characterized in that, Includes the following steps: S1: Preparation of rare earth modified carbon nanotubes After carboxylation, multi-walled carbon nanotubes are dispersed in anhydrous ethanol and then mixed with a rare earth citric acid coupling agent solution to react and obtain rare earth modified carbon nanotubes. S2: Preparation of base copper alloy wire S2.1: Add high-purity electrolytic copper into a vacuum induction melting furnace, evacuate the furnace, fill it with high-purity argon, and then heat it at 1300-1400℃ until the copper is completely melted. Then add Cu-Cr master alloy and Cu-Zr master alloy, stir and melt for 20-30 minutes to obtain the alloy melt. S2.2: Using high-purity argon gas at 3-5 MPa as the atomizing medium, the above alloy melt flow is crushed into droplets, and then rapidly condensed into powder in an atomizing tower protected by nitrogen to obtain pre-alloyed powder. S2.3: Place the above rare earth modified carbon nanotubes, the above pre-alloyed powder, Cu-Hf master alloy and Cu-Ce master alloy into a ball mill jar and ball mill for 3-4 hours under argon protection to obtain composite powder; S2.4: Add the above composite powder and high-purity electrolytic copper into a vacuum induction melting furnace, evacuate the furnace, fill it with high-purity argon gas for protection, melt at 1200-1250℃ for 1-1.5h, and then cast it into an ingot to obtain an alloy ingot. S2.5: Under argon protection, the above alloy ingot is annealed at 900-950℃ for 2-4 hours, then hot rolled and low temperature drawn, and then aged at 390-420℃ for 1-2 hours, and then aged at 450-480℃ for 2-3 hours. After cooling, the base copper alloy wire is obtained. S3: Preparation of copper alloy wires After pretreatment of the above-mentioned copper alloy base wire, a Pd-Co gradient transition layer is first deposited, followed by a pure Pd layer to form a corrosion-resistant protective layer, thus obtaining a copper alloy conductor.
2. The manufacturing process of a high-performance copper alloy wire according to claim 1, characterized in that, S1 includes the following steps: S1.1: Add multi-walled carbon nanotubes to the acidification solution at a ratio of 1g:(10-12)mL, disperse by ultrasonication for 30-40min, then heat and reflux at 70-80℃ for 3-4h, cool, filter, wash until neutral and vacuum dry to obtain carboxylated carbon nanotubes; S1.2: Add citric acid monohydrate to deionized water at a ratio of 1g:(15-25)mL, heat and stir at 50-60℃ to dissolve, then add lanthanum nitrate and cerium nitrate, continue stirring to dissolve, adjust the pH to 5-6 with dilute ammonia, and heat and stir at 60-70℃ for 1-2 hours to obtain rare earth citric acid coupling agent solution. S1.3: Under nitrogen protection, the above carboxylated carbon nanotubes were added to anhydrous ethanol at a ratio of 1g:(80-100)mL, and ultrasonically dispersed for 30-40min to obtain a carboxylated carbon nanotube dispersion. Then, the above rare earth citric acid coupling agent solution was added, and the mixture was heated and stirred at 60-70℃ for 4-5h. After cooling, the mixture was filtered, washed, and vacuum dried to obtain rare earth modified carbon nanotubes.
3. The manufacturing process of a high-performance copper alloy wire according to claim 2, characterized in that, S3 includes the following steps: S3.1: Immerse the base copper alloy wire obtained in step S2.5 in anhydrous ethanol, ultrasonically clean for 3-5 minutes, then ultrasonically clean with deionized water for 1-3 minutes, and dry with nitrogen to obtain the pretreated wire. S3.2: The pretreated wire is fed into the ALD reaction chamber, preheated to 180-200℃ and kept at that temperature for 10-20 min, then treated with hydrogen plasma for 3-5 min. The vacuum degree of the ALD reaction chamber is then adjusted to 5-10 Pa, and high-purity argon gas with a flow rate of 50-100 sccm is introduced. Di(hexafluoroacetylacetone)palladium is used as the palladium precursor, di(acetylacetone)cobalt is used as the cobalt precursor, and high-purity hydrogen is used as the reaction gas. A general pulse timing is set, and a Pd-Co gradient transition layer is deposited on the surface of the pretreated wire to obtain a single-layer wire. S3.3: Then stop the introduction of cobalt di(acetylacetone) and introduce only palladium di(hexafluoroacetylacetone) and high-purity hydrogen. Keep the general pulse timing unchanged and deposit a pure Pd layer on the surface of the Pd-Co gradient transition layer of the single-layer wire. The total cycle is 35 cycles. Then, it is naturally cooled under argon purging to form a corrosion-resistant protective layer and obtain a copper alloy wire.
4. The manufacturing process of a high-performance copper alloy wire according to claim 2, characterized in that, The acidification solution is prepared by mixing concentrated nitric acid and concentrated sulfuric acid in a volume ratio of 1:
3.
5. The manufacturing process of a high-performance copper alloy wire according to claim 2, characterized in that, The molar ratio of citric acid monohydrate, lanthanum nitrate, and cerium nitrate is (2.8-3):(0.8-1):
1.
6. The manufacturing process of a high-performance copper alloy wire according to claim 2, characterized in that, The volume ratio of rare earth citric acid coupling agent solution to carboxylated carbon nanotube dispersion is 1:(4-5).
7. The manufacturing process of a high-performance copper alloy conductor according to claim 1, characterized in that, By mass percentage, the base copper alloy wire comprises: 0.4-0.6% Cr, 0.05-0.2% Zr, 0.05-0.06% Hf, 0.01-0.03% Ce, 0.4-0.5% rare earth modified carbon nanotubes, with the balance being Cu.
8. The manufacturing process of a high-performance copper alloy wire according to claim 3, characterized in that, The general pulse timing set in step S3.2 is as follows: precursor pulse 0.8s, purge 2.5s, hydrogen reaction pulse 1.5s, purge 2.5s.
9. The manufacturing process of a high-performance copper alloy conductor according to claim 3, characterized in that, The total number of cycles for depositing the Pd-Co gradient transition layer was 22. The first segment has a 1:2 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt, with a deposition cycle of 7 cycles. The second segment has a 1:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt, with a deposition cycle of 8 cycles. The third segment has a 2:1 ratio of bis(hexafluoroacetylacetone)palladium to bis(acetylacetone)cobalt, with a deposition cycle of 7 cycles.
10. A high-performance copper alloy conductor, characterized in that, It is prepared by the manufacturing process of a high-performance copper alloy wire as described in any one of claims 1-9.