Preparation method of antioxidant alloy copper wire

Abstract

This invention relates to the field of non-ferrous metal processing technology, specifically to a method for preparing antioxidant alloy copper wire. The invention involves stepwise melting of pure copper metal, pure nickel metal, zinc ingots, tin granules, copper-yttrium master alloy, and copper-boron master alloy to obtain an alloy melt; after casting, it undergoes temperature-change rotary forging, high-pressure spray cooling, and drawing to obtain a copper wire semi-finished product; the copper wire semi-finished product is then subjected to ultrasonic cleaning, drying, and gradient annealing to obtain the alloy copper wire. This invention utilizes the synergistic effect of trace elements, combined with rotary forging to densify the microstructure, cleaning to remove carbon, and dew point controlled annealing processes, to generate a dense composite oxide film in situ on the surface of the copper wire. This method endows the alloy copper wire with excellent antioxidant and corrosion resistance properties, making it suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention relates to the field of non-ferrous metal processing technology, specifically to a method for preparing an antioxidant alloy copper wire. Background Technology

[0002] As electronic components become increasingly miniaturized and highly integrated, the requirements for bonding wires and high-frequency transmission conductors, which are key connection materials, are becoming increasingly stringent. Currently, high-performance copper alloys for electronics are gradually replacing expensive gold and silver wires as the mainstream. However, the inherent chemical reactivity of copper-based materials makes them highly susceptible to oxidation under high-temperature bonding or long-term service conditions, leading to increased contact resistance, solder joint failure, or signal transmission loss. Existing conventional technologies often employ microalloying of high-purity copper (4N / 5N copper) in an attempt to improve mechanical strength while maintaining high conductivity.

[0003] Although existing copper alloy technology is relatively mature, it still has significant drawbacks: First, it has poor oxidation resistance. When ordinary copper alloys are exposed to environments above 150°C for extended periods, a loose mixed layer of copper oxide and cuprous oxide easily forms on the surface, and this oxide layer can penetrate inward along grain boundaries, leading to subcutaneous corrosion. Second, it has poor corrosion resistance. In humid or sulfur- and chlorine-containing industrial atmospheric environments, copper wires are highly susceptible to intergranular corrosion and stress corrosion cracking. Traditional solutions such as surface plating with palladium or gold significantly increase costs, and the adhesion between the plating layer and the substrate, as well as the matching of thermal expansion coefficients, often become new sources of failure.

[0004] Therefore, a method for preparing antioxidant alloy copper wire is proposed. Summary of the Invention

[0005] The purpose of this invention is to design a method for preparing antioxidant alloy copper wire. This invention involves stepwise melting of pure copper metal, pure nickel metal, zinc ingots, tin granules, copper-yttrium master alloy, and copper-boron master alloy to obtain an alloy melt; after casting, it undergoes temperature-change rotary forging, high-pressure spray cooling, and drawing to obtain a copper wire semi-finished product; the copper wire semi-finished product is then subjected to ultrasonic cleaning, drying, and gradient annealing to obtain the alloy copper wire. This invention utilizes the synergistic effect of trace elements, combined with rotary forging to densify the microstructure, cleaning to remove carbide, and dew point controlled annealing processes, to generate a dense composite oxide film in situ on the surface of the copper wire. This method endows the alloy copper wire with excellent antioxidant and corrosion resistance properties, making it suitable for large-scale industrial production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing antioxidant alloy copper wire, comprising the following steps: Pure copper metal, pure nickel metal, zinc ingots, tin granules, copper yttrium master alloy, and copper boron master alloy are melted in stages to obtain an alloy melt. After casting, the alloy melt is subjected to rotary forging and cooling drawing to obtain copper wire semi-finished products. The copper wire semi-finished products are then cleaned, dried, and subjected to gradient annealing to obtain alloy copper wire.

[0007] Preferably, the proportions of each metal element in the alloy melt, calculated by mass percentage, are as follows: nickel 0.2%-0.4%; zinc 0.1%-0.3%; tin 0.05%-0.1%; yttrium 0.01%-0.03%; boron 0.002%-0.005%; with the balance being copper.

[0008] Preferably, the specific process of step-by-step melting is as follows: pure copper metal is added to the crucible of a vacuum induction melting furnace, the vacuum pump is started, and when the pressure inside the furnace reaches 1.0 × 10⁻⁶... -2 When the pressure is below Pa, start heating to 1140-1160℃ and maintain the temperature for 10 minutes. Then add pure nickel metal and tin granules and mix with electromagnetic stirring for 5 minutes. Then add copper-yttrium master alloy (yttrium content of 10 wt%) and copper-boron master alloy (boron content of 4 wt%). After reacting for 2 minutes, adjust the pressure in the furnace and fill with high-purity argon gas to 0.1 MPa. Then quickly add zinc ingots and stir for 1 minute to obtain the alloy melt.

[0009] Preferably, the specific process of rotary forging is as follows: the alloy melt is cast using a hot continuous casting process, the mold temperature is 1200℃, the cooling end water temperature is 20℃, and the drawing speed is 145-155mm / min to obtain a cast copper rod (Φ8.0mm); the cast copper rod is induction heated to 390-410℃ and fed into a four-hammer rotary forging mill, the feeding speed is 2m / min, the forging frequency is 50Hz, the total machining rate is 60% (section reduction rate), and it is rotary forged to Φ3.2mm to obtain a pretreated copper rod.

[0010] Preferably, the specific process of cooling and drawing is as follows: using an all-oil-based lubricant, controlling the oil temperature below 40℃, and applying a spray with a pressure of 0.4MPa to lubricate and cool the pretreated copper rod; using a polycrystalline diamond mold, drawing the pretreated copper rod to the finished wire diameter (Φ0.05mm), with a single pass reduction rate of 15%-20%, gradually accelerating, and finally reaching a pass speed of 850m / min, with the die entry angle set at 8°-10° to obtain a copper wire semi-finished product.

[0011] Preferably, the all-oil-based lubricant is a low-viscosity copper wire drawing oil formulated with liquid paraffin (CAS No.: 8042-47-5) as the base oil, with a kinematic viscosity of 5-10 mmHg at 40°C. 2 / s, flash point above 130℃.

[0012] Preferably, the specific process of cleaning and drying is as follows: the copper wire semi-finished product is continuously passed through a multi-stage ultrasonic cleaning tank, the cleaning medium is a hydrocarbon cleaning agent, the ultrasonic frequency is set to 50-70kHz, and the cleaning time is 10s; then it is dried by a high-pressure hot air knife (using nitrogen flow), the air pressure is 0.5MPa, and the air temperature is 60℃, to obtain the cleaned copper wire.

[0013] Preferably, the hydrocarbon cleaning agent is petroleum ether (CAS No.: 64742-48-9).

[0014] Preferably, the gradient annealing process is as follows: the cleaned copper wire is passed through the first stage at a temperature of 510-530℃ in a mixed gas of nitrogen and hydrogen (hydrogen accounts for 10%), with a residence time of 2 seconds; then it enters the second stage at a temperature of 375-385℃ in a high-purity nitrogen atmosphere, with a trace amount of water vapor applied by a humidifier to control the dew point of the introduced gas between -30℃ and -20℃; finally, the third stage is carried out in a high-purity nitrogen atmosphere, where the cleaned copper wire is cooled to below 60℃ and removed from the furnace to obtain alloy copper wire.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention, by adding trace amounts of Zn, Ni, and Sn elements and controlling the dew point in the second stage of gradient annealing, utilizes the principle of thermodynamic selective oxidation to induce Zn and Ni atoms inside the copper matrix to diffuse to the surface. Under a specific oxygen partial pressure that prevents copper oxidation, these reactive elements form a dense nickel-zinc composite oxide protective film in situ on the copper wire surface. This oxide film effectively prevents oxygen atoms from penetrating inward during high-temperature bonding or long-term thermal aging, significantly improving the oxidation resistance of the copper wire under high-temperature conditions.

[0016] This invention utilizes a stepwise melting process to introduce rare earth element Y and trace element B, constructing a dual grain boundary protection mechanism of purification and filling. Y preferentially reacts with impurities to form stable inclusions, purifying the grain boundary channels; while B, with its extremely small atomic radius, fills the grain boundary vacancies, reducing the grain boundary energy. This microscopic composition design effectively cuts off the pathways for chloride and sulfur ions to penetrate along the grain boundaries, resulting in alloy copper wires that exhibit significantly superior corrosion resistance compared to ordinary copper alloys under harsh environments such as salt spray and high humidity.

[0017] This invention incorporates ultrasonic cleaning and high-pressure hot air drying processes using petroleum ether as the medium. Since the preceding process employs hydrophobic liquid paraffin as a fully oil-based lubricant, incomplete cleaning can lead to residual oil decomposing into carbon within the annealing furnace, disrupting the reduction / oxidation balance of the trace oxygen atmosphere. The cleaning steps of this invention thoroughly remove the surface oil film, ensuring the copper wire enters the annealing furnace in a bare metal state. This guarantees that the surface composite oxide film grows directly on a pure substrate, preventing blistering or peeling caused by carbon deposition beneath the film layer, and further strengthening the anti-oxidation effect.

[0018] This invention employs a temperature-controlled rotary forging process to replace traditional rough drawing. Utilizing high-frequency radial forging with four hammers, it effectively breaks down casting grains and compresses internal shrinkage defects, significantly improving the density of the copper wire. Combined with subsequent high-pressure spray cooling drawing, the finished copper wire exhibits extremely high surface smoothness and is free of microcracks. This dense physical structure reduces the retention points and reaction sites of corrosive media on the material surface, thus contributing to a structural improvement in overall corrosion resistance.

[0019] The gradient annealing process of this invention has a unique solute pumping effect. During the annealing process, solid solution atoms (Zn, Ni) inside the alloy are enriched on the surface under the drive of chemical potential to participate in film formation. This special gradient distribution structure allows antioxidant elements to be concentrated in the outermost layer of the material in contact with the external environment. Thus, without significantly increasing the total amount of alloy added, a dense and robust composite oxide protective shell is constructed through the surface enrichment effect, which significantly improves the chemical inertness and environmental adaptability of the copper wire surface and ensures its long-term structural stability under high temperature or harsh environments. Attached Figure Description

[0020] Figure 1 The diagram shows the antioxidant properties of Example 1 and Comparative Examples 7-8 in this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] For details, please refer to [link / reference]. Figure 1 This invention provides a method for preparing antioxidant alloy copper wire, the technical solution of which is as follows: Example 1 Pure copper metal is added to the crucible of a vacuum induction melting furnace, and the vacuum pump is started. When the pressure inside the furnace reaches 1.0 × 10⁻⁶, the process continues. - 2When the pressure is below Pa, start heating to 1150℃ and maintain the temperature for 10 minutes. Then add pure nickel metal and tin granules and mix with electromagnetic stirring for 5 minutes. Then add copper-yttrium master alloy (yttrium content of 10 wt%) and copper-boron master alloy (boron content of 4 wt%). After reacting for 2 minutes, adjust the pressure in the furnace and fill with high-purity argon gas to 0.1 MPa. Then quickly add zinc ingots and stir for 1 minute to obtain alloy melt. The percentage of each metallic element in the alloy melt by mass is as follows: nickel 0.3%; zinc 0.2%; tin 0.08%; yttrium 0.02%; boron 0.004%; with the balance being copper. The alloy melt was cast using a hot continuous casting process at a mold temperature of 1200℃, a cooling water temperature of 20℃, and a drawing speed of 150mm / min to obtain a cast copper rod (Φ8.0mm). The cast copper rod was then induction heated to 400℃ and fed into a four-hammer rotary forging mill at a feed rate of 2m / min, a forging frequency of 50Hz, and a total machining rate of 60% (section reduction rate) to obtain a pretreated copper rod with a diameter of Φ3.2mm. Using an all-oil-based lubricant, the oil temperature is controlled below 40℃, and a spray with a pressure of 0.3MPa is applied to lubricate and cool the pretreated copper rod. Using a polycrystalline diamond mold, the pretreated copper rod is drawn to the finished wire diameter (Φ0.05mm), with a single pass reduction rate of 18%. The speed is gradually increased, and the final pass speed reaches 850m / min. The die entry angle is set to 9° to obtain a copper wire semi-finished product. The copper wire semi-finished product is continuously passed through a multi-stage ultrasonic cleaning tank. The cleaning medium is a hydrocarbon cleaning agent, the ultrasonic frequency is set to 60kHz, and the cleaning time is 10s. Then it is dried by a high-pressure hot air knife (using nitrogen flow) with an air pressure of 0.5MPa and an air temperature of 60℃ to obtain the cleaned copper wire. The cleaned copper wire is passed through the first stage at a temperature of 520°C in an atmosphere of a mixture of nitrogen and hydrogen (10% hydrogen) for 2 seconds. Then it enters the second stage at a temperature of 380°C in an atmosphere of high-purity nitrogen, with a small amount of water vapor added by a humidifier to control the dew point of the gas at -25°C. Finally, it enters the third stage in an atmosphere of high-purity nitrogen, where the cleaned copper wire is cooled to below 60°C before being removed from the furnace, thus obtaining alloy copper wire.

[0023] Examples 2-5 refer to the parameter conditions in Example 1, with specific differences shown in Table 1.

[0024] Table 1 Parameters and conditions for Examples 1-5 Comparative Example 1 follows the same parameters and conditions as in Example 1, except that zinc is not added.

[0025] Comparative Example 2 follows the same parameters and conditions as in Example 1, except that nickel is not added.

[0026] Comparative Example 3 follows the same parameters and conditions as in Example 1, except that tin is not added.

[0027] Comparative Example 4 follows the same parameters and conditions as in Example 1, except that yttrium is not added.

[0028] Comparative Example 5 follows the same parameters and conditions as in Example 1, except that boron is not added.

[0029] Comparative Example 6 follows the same parameters and conditions as in Example 1, except that step-by-step melting is not performed; all raw materials are melted at once to obtain an alloy melt.

[0030] Experimental Example 1: Antioxidant and Corrosion Resistance The average oxidation rate of Examples 1-5 and Comparative Examples 1-6 was tested at 200℃ for 100 hours. The time for the first appearance of etch pits in Examples 1-5 and Comparative Examples 1-6 was tested according to GB / T10125 standard. The solution was a 5% NaCl neutral solution, the temperature was 35℃±2℃, and the spraying method was continuous spraying. Examples 1-5 and Comparative Examples 1-6 were immersed in a 0.05% sodium sulfide solution, and the time required for the copper wire surface to turn completely black was recorded. The results are shown in Table 2.

[0031] Table 2. Antioxidant and corrosion resistance properties of Examples 1-5 and Comparative Examples 1-6 Table 2 shows that in Comparative Example 1, without the addition of zinc, the average oxidation rate increased significantly, and the salt spray resistance life decreased sharply. This indicates that although nickel provides some chemical stability, the lack of zinc prevents the preferential formation of zinc oxide components on the surface during annealing due to zinc's high diffusion rate. Consequently, a dense composite oxide structure cannot be constructed with nickel. The loose structure of a single nickel oxide or copper oxide layer cannot effectively block the intrusion of oxygen atoms and chloride ions, leading to a significant decrease in oxidation and corrosion resistance. Comparative Example 2, without the addition of nickel, exhibits poor salt spray resistance. This is because although the oxide film formed solely by zinc has a fast formation rate, it has poor chemical stability in a humid environment containing chloride ions and is highly susceptible to pitting corrosion. The absence of nickel deprives the oxide film of its chemically inert framework, making it unable to resist the anodic dissolution process of electrochemical corrosion. Comparative Example 3, which did not contain tin, performed better than other comparative examples, but was still significantly lower than Example 1. Experimental data showed a slight increase in its oxidation rate. This is because tin atoms play a role in filling gaps and regulating the lattice in the oxide film. Without tin, the resulting composite oxide film was not ideal and was more prone to microcracks during the 200°C high-temperature test, leading to some oxygen penetration. This indicates that tin has an auxiliary and synergistic effect in maintaining the physical integrity of the oxide film under extreme environments. Comparative Example 4 showed a short sulfidation discoloration time and an extremely short salt spray resistance time. Yttrium, as a rare earth element, plays a crucial role in capturing sulfur and oxygen impurities in the matrix and purifying grain boundaries. Without yttrium, impurities agglomerated at the grain boundaries, forming highly active corrosion channels. In sodium sulfide solution, sulfur ions rapidly penetrated inward along the open grain boundaries, causing the copper wire to turn black instantly. Comparative Example 5, which did not include boron, also showed a significant decline in corrosion resistance. Boron atoms fill high-energy vacancies at grain boundaries; the absence of boron means a large number of diffusion voids exist at these boundaries. Although yttrium purified the impurities, physical channels still exist, allowing chloride and sulfide ions to diffuse rapidly through these vacancies, resulting in corrosion resistance far inferior to Example 1. Comparative Example 6 employed a process where all raw materials were melted in a single step, leading to unstable and poor performance across various indicators. Due to the extremely low content and high chemical reactivity of yttrium and boron, their direct addition without step-by-step melting and deoxidation easily reacts with oxygen in the molten copper to form oxide slag, which is then removed, resulting in extremely low actual alloying efficiency. Furthermore, the high-melting-point nickel and low-melting-point zinc were not fully and uniformly mixed, causing component segregation in the microstructure. This microstructural inhomogeneity prevented the formation of a continuous and consistent protective film on the copper wire surface, and the internal potential difference accelerated electrochemical corrosion.

[0032] Examples 6-9 refer to the parameter conditions in Example 1, with specific differences shown in Table 3.

[0033] Table 3 Parameter conditions for Examples 1 and 6-9 Comparative Example 7 follows the same parameters and conditions as in Example 1, except that no cleaning and drying process is performed.

[0034] Comparative Example 8 uses the same parameters and conditions as in Example 1, except that a traditional rough drawing process is used instead of rotary forging, in which the cast copper rod is longitudinally stretched through a die.

[0035] Comparative Example 9 uses the same parameters and conditions as in Example 1, except that the dew point of the gas is 10°C during the gradient annealing process.

[0036] Comparative Example 10 follows the same parameters and conditions as in Example 1, except that a traditional annealing process is used. The cleaned copper wire is passed through an annealing furnace at 500°C in a nitrogen atmosphere for 3 seconds, and then directly cooled and removed from the furnace.

[0037] Experimental Example 2: Antioxidant and Corrosion Resistance The antioxidant and corrosion resistance properties of Examples 1, 6-9, and Comparative Examples 7-10 were tested according to the test method of Experimental Example 1. The results are shown in Table 4. The antioxidant properties of Examples 1 and Comparative Examples 7-8 are as follows: Figure 1 As shown.

[0038] Table 4. Antioxidant and corrosion resistance properties of Examples 1, 6-9, and Comparative Examples 7-10 From Table 4 and Figure 1It can be observed that Comparative Example 7, which omitted the cleaning and drying process, showed a significant decrease in its antioxidant and corrosion resistance compared to Example 1. This is because the all-oil-based lubricant used in the previous process has strong adhesion. If it is not thoroughly removed by a hydrocarbon cleaning agent, a trace amount of oil film will remain on the surface of the copper wire. When the copper wire carrying the oil film enters the high-temperature annealing furnace, the organic oil molecules decompose to generate carbon (C), which will have two serious consequences: First, the residual carbon forms a strong reducing atmosphere in the microscopic local area, interfering with the micro-oxygen partial pressure environment preset in this invention and hindering the oxidation film formation reaction of Ni and Zn atoms; Second, the deposited carbon particles are impurities trapped between the oxide film and the substrate, resulting in poor adhesion of the protective film, and even bubbles and peeling. In the salt spray test, the residual carbon spots also become microscopic cathodes, forming a galvanic cell with the copper substrate, which accelerates the electrochemical corrosion. Comparative Example 8 used traditional rough drawing instead of the temperature-change rotary forging process of this invention. Its average oxidation rate increased, and its corrosion resistance was significantly weaker than that of Example 1. The fundamental reason lies in the different stress states of the processing methods. Traditional drawing involves longitudinal tensile stress, which easily elongates the micro-shrinkage and porosity generated during casting along the axial direction, forming a series of micro-defects and even inducing microcracks at grain boundaries. In contrast, the rotary forging process used in this invention applies high-frequency radial compressive stress, which can effectively forge and close casting defects, significantly improving the physical density of the material. The loose microstructure in Comparative Example 8 provides a convenient physical channel for the invasion of oxygen atoms and chloride ions, making it easier for corrosive media to remain on the material surface and in shallow defects, thereby accelerating pitting corrosion. Comparative Example 9, with its annealing atmosphere dew point increased to 10°C, exhibited the worst performance among all comparative examples. According to the thermodynamics of metal oxidation, under the high oxygen partial pressure corresponding to a dew point of 10°C, the Gibbs free energy of the copper oxidation reaction becomes negative. This means that not only Zn and Ni will oxidize, but the base copper will also undergo severe oxidation, forming a loose and porous mixed layer of copper oxide and cuprous oxide, rather than the dense nickel-zinc composite film required by this invention. This loose oxide layer lacks protective capabilities and is prone to peeling due to the mismatch in volume expansion coefficients, causing the copper wire to fail rapidly in harsh environments. Comparative Example 10 uses the traditional one-step annealing method at 500°C. Although it can eliminate work hardening, its corrosion resistance is far inferior to that of Example 1. This is because a single high-temperature process cannot simultaneously address surface activation and film formation control. At 500°C, the atomic diffusion rate is too fast and the surface oxidation reaction is difficult to control, easily leading to the formation of disordered mixed oxides or internal oxidation on the surface, failing to form a continuous, dense, and uniformly thick protective layer. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an antioxidant alloy copper wire, characterized in that, Includes the following steps: Pure copper metal, pure nickel metal, zinc ingots, tin granules, copper-yttrium master alloy, and copper-boron master alloy are melted in stages to obtain an alloy melt; the alloy melt is then cast and subjected to rotary forging and cooling drawing to obtain a copper wire semi-finished product; the copper wire semi-finished product is then cleaned, dried, and subjected to gradient annealing to obtain the alloy copper wire.

2. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The proportions of each metallic element in the alloy melt, calculated by mass percentage, are as follows: nickel 0.2%-0.4%; zinc 0.1%-0.3%. Tin accounts for 0.05%-0.1%; yttrium accounts for 0.01%-0.03%; boron accounts for 0.002%-0.005%; the balance is copper.

3. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The specific process of the step-by-step melting is as follows: pure copper metal is added to the crucible of a vacuum induction melting furnace, followed by pure nickel metal and tin granules. After stirring and mixing, copper-yttrium master alloy and copper-boron master alloy are added. After the reaction, argon gas is introduced, zinc ingots are added, and the alloy melt is obtained after stirring.

4. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The specific process of the rotary forging is as follows: the alloy melt is cast to obtain a cast copper rod; the cast copper rod is induction heated to 390-410℃ and sent to a four-hammer rotary forging machine for forging to obtain a pre-treated copper rod.

5. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The specific process of the cooling and drawing treatment is as follows: using an all-oil-based lubricant to lubricate and cool the pretreated copper rod; using a polycrystalline diamond mold to draw the pretreated copper rod to the finished wire diameter to obtain the copper wire semi-finished product.

6. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The specific process of the cleaning and drying treatment is as follows: the copper wire semi-finished product is passed through an ultrasonic cleaning tank, the cleaning medium is a hydrocarbon cleaning agent, and after cleaning, it is dried by hot air to obtain the cleaned copper wire.

7. The method for preparing an antioxidant alloy copper wire according to claim 1, characterized in that, The specific process of the gradient annealing treatment is as follows: the cleaned copper wire is passed through the first stage at a temperature of 510-530℃ in a mixed gas atmosphere of nitrogen and hydrogen; then it enters the second stage at a temperature of 375-385℃ in a high-purity nitrogen and water vapor atmosphere, controlling the dew point of the introduced gas between -30℃ and -20℃; finally, the third stage is carried out in a high-purity nitrogen atmosphere, and the cleaned copper wire is gas-cooled out of the furnace to obtain the alloy copper wire.

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