Overhead high-conductivity steel-cored aluminum stranded wire

Abstract

The invention relates to the technical field of steel-cored aluminum stranded wires, and provides an overhead high-conductivity steel-cored aluminum stranded wire which comprises a galvanized steel core and aluminum wires stranded on the surface of the galvanized steel core, the galvanized steel core is formed by stranding 19 steel wires, and the aluminum wires are divided into two layers and stranded on the outer side of the galvanized steel core; the preparation method of the galvanized steel core comprises the following steps that after being galvanized, a steel wire is added into a passivation solution to be passivated, and the galvanized steel core is obtained after drying and twisting; the passivation solution is prepared from the following raw material components: waterborne acrylic resin, nickel nitrate, sodium carboxymethyl cellulose, sodium dodecyl sulfate, functionalized single-walled carbon nanotubes and water; the functionalized single-walled carbon nanotube is prepared from the following raw materials: a single-walled carbon nanotube and 5-carboxyl-2, 3-diaminopyridine. According to the technical scheme, the problem that the corrosion resistance of the manufactured overhead steel-cored aluminum stranded wire is poor due to the fact that the corrosion resistance of a galvanized steel core is poor in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of steel core aluminum stranded wires, and in particular to an overhead high-conductivity steel core aluminum stranded wire. Background Art

[0002] Amidst the accelerating transformation of the global energy structure and the continuous upgrading of power infrastructure, overhead transmission lines, as a key means of power transmission, face a significant impact on the stability of energy supply, with their safety and reliability directly impacting the overall stability of the energy supply. With the increasing density of urban power grids and the large-scale construction of new energy projects such as offshore wind power, transmission lines face increasingly complex and variable service environments. These harsh conditions, particularly coastal salt spray, acid-base corrosion in industrially polluted areas, and areas prone to acid rain, place stringent demands on the corrosion resistance of overhead lines. Steel-core aluminum stranded wire, with its combination of high steel core strength and excellent aluminum conductivity, is widely used in overhead power transmission. However, the corrosion resistance of traditional steel-core aluminum stranded wire is limited. Its steel core is easily corroded by environmental media, and rust occurs, resulting in a decrease in mechanical strength. In severe cases, there is even a risk of wire breakage. In order to prevent the steel core from being corroded, galvanizing is often performed on the surface of the steel core. Since the galvanized layer is easily corroded in a humid environment, passivation treatment is usually performed after galvanizing. However, the passivation film formed after passivation is not dense enough, resulting in poor corrosion resistance of the galvanized steel core, so that the steel core cannot be protected in the long term. Therefore, the development of a steel-core aluminum stranded wire with high corrosion resistance to extend the service life of the line is of great significance to promoting the sustainable development of the power industry. Summary of the Invention

[0003] The present invention provides an overhead high-conductivity steel-core aluminum stranded wire, which solves the problem in the related art that the galvanized steel core has poor corrosion resistance, resulting in poor corrosion resistance of the resulting overhead steel-core aluminum stranded wire.

[0004] The technical solutions of the present invention are as follows: The present invention provides a high-conductivity steel-core aluminum stranded wire for overhead use, comprising a galvanized steel core and aluminum wires stranded on the surface of the galvanized steel core, wherein the galvanized steel core is formed by twisting 19 steel wires, and the aluminum wires are divided into two layers and stranded on the outside of the galvanized steel core; a method for preparing the galvanized steel core comprises the following steps: galvanizing the steel wires, adding them into a passivation solution for passivation, and drying and twisting them to obtain the galvanized steel core; the raw materials of the passivation solution are composed of the following components by weight percentage: 15% to 20% water-based acrylic resin, 10% to 15% nickel nitrate, 3% to 8% sodium carboxymethyl cellulose, 0.5% to 1% sodium dodecyl sulfate, 5% to 10% functionalized single-walled carbon nanotubes, and the balance being water; the raw materials of the functionalized single-walled carbon nanotubes include single-walled carbon nanotubes and 5-carboxyl-2,3-diaminopyridine.

[0005] As a further technical solution, the mass ratio of the single-walled carbon nanotubes to 5-carboxy-2,3-diaminopyridine is 50:1-5, for example, 50:1, 50:2, 50:3, 50:4, or 50:5.

[0006] In the passivation solution used in the overhead high-conductivity steel-core aluminum stranded wire of the present invention, 5-carboxyl-2,3-diaminopyridine is compounded with carbon nanotubes through hydrogen bonds. By limiting the mass ratio of single-walled carbon nanotubes to 5-carboxyl-2,3-diaminopyridine to 50:1-5, 5-carboxyl-2,3-diaminopyridine can be uniformly adsorbed on the surface of the single-walled carbon nanotubes, effectively preventing the agglomeration of the carbon nanotubes, making the structure of the passivation film denser and more uniform, and improving the corrosion resistance of the overhead high-conductivity steel-core aluminum stranded wire.

[0007] As a further technical solution, the method for preparing functionalized single-walled carbon nanotubes comprises the following steps: S1, adding single-walled carbon nanotubes to sulfuric acid for a first mixing, adding nitric acid for a second mixing, and drying to obtain pretreated carbon nanotubes; S2. Adding the pretreated carbon nanotubes and 5-carboxyl-2,3-diaminopyridine into dimethyl sulfoxide and mixing them for the third time, and drying to obtain functionalized carbon nanotubes.

[0008] As a further technical solution, the concentration of the sulfuric acid is 28 wt %, and the concentration of the nitric acid is 68 wt %.

[0009] As a further technical solution, the mass volume ratio of the single-walled carbon nanotubes, sulfuric acid and nitric acid is 1g:10mL:1mL.

[0010] As a further technical solution, the raw material of the functionalized single-walled carbon nanotubes further includes polyacrylic acid.

[0011] In the passivation liquid used in the overhead high-conductivity steel-core aluminum stranded wire of the present invention, polyacrylic acid is further added to the raw materials of the functionalized single-walled carbon nanotubes. The polyacrylic acid has adhesiveness and dispersibility and is weakly acidic. By adding polyacrylic acid to the functionalized single-walled carbon nanotubes, the dispersibility of the single-walled carbon nanotubes can be further improved, and the compatibility with the water-soluble acrylic acid matrix can be improved, so that the formed network structure is denser. The weakly acidic polyacrylic acid can adjust the pH value of the passivation liquid and help control the growth rate of the passivation film. At the same time, the carboxyl group in the polyacrylic acid can improve the adsorption capacity of the passivation liquid and the galvanized layer, further improving the corrosion resistance of the steel core, thereby further improving the corrosion resistance of the overhead high-conductivity steel-core aluminum stranded wire.

[0012] As a further technical solution, the mass ratio of the single-walled carbon nanotubes to the polyacrylic acid is 50:1-2, for example, 50:1, 50:1.2, 50:1.5, 50:1.6, 50:1.8, or 50:2.

[0013] As a further technical solution, the method for preparing functionalized single-walled carbon nanotubes comprises the following steps: A1. adding single-walled carbon nanotubes to sulfuric acid for a first mixing, adding nitric acid for a second mixing, and drying to obtain pretreated carbon nanotubes; A2. Add the pretreated carbon nanotubes, 5-carboxyl-2,3-diaminopyridine, and polyacrylic acid into dimethyl sulfoxide and mix for the third time, and then dry to obtain functionalized carbon nanotubes.

[0014] As a further technical solution, in step S1 and step A1, the temperature of the first mixing is independently 70-80° C., and the time of the first mixing is independently 6-10 h.

[0015] As a further technical solution, in step S1 and step A1, the temperature of the second mixing is independently 25-30° C., and the time of the second mixing is independently 20-24 h.

[0016] As a further technical solution, in step S1 and step A1, after the second mixing, the pretreated carbon nanotubes are obtained by washing with water and drying.

[0017] As a further technical solution, in step S1 and step A1, the temperature of the third mixing is independently 40-60° C., and the time of the third mixing is independently 2-4 hours.

[0018] As a further technical solution, the galvanizing process further includes alkali washing, pickling and auxiliary plating.

[0019] As a further technical solution, during the alkali washing, the alkali washing liquid is a sodium hydroxide aqueous solution.

[0020] In the galvanized steel core of the overhead high-conductivity steel-core aluminum stranded wire of the present invention, since impurities such as oil, grease, lubricant and some dust will remain on the surface of the steel core during the processing process, the sodium hydroxide aqueous solution can convert the oil-like substances into water-soluble substances through a saponification reaction through alkali washing, and can also suspend or dissolve some impurities such as dust, thereby effectively removing various pollutants on the surface of the steel core, providing better adhesion conditions for the galvanized layer, enabling the galvanized layer to adhere more firmly to the surface of the steel core, and ensuring the adhesion and corrosion resistance of the galvanized layer.

[0021] As a further technical solution, the concentration of the sodium hydroxide aqueous solution is 8wt%~10wt%, for example, it can be 8wt%, 8.5wt%, 9wt%, 9.5wt%, and 10wt%.

[0022] As a further technical solution, the alkali washing temperature is 70-80° C., and the alkali washing time is 30-40 minutes.

[0023] As a further technical solution, during the pickling, the pickling solution includes one or both of hydrochloric acid and sulfuric acid.

[0024] In the galvanized steel core of the overhead high-conductivity steel-core aluminum stranded wire of the present invention, the steel core is pickled using hydrochloric acid and / or sulfuric acid. The hydrochloric acid and / or sulfuric acid can chemically react with the rust on the surface of the steel core, thereby effectively removing impurities such as rust and oxide scale on the surface of the steel core, providing a clean surface for subsequent plating and galvanizing processes.

[0025] As a further technical solution, when the pickling solution includes hydrochloric acid, the concentration of the hydrochloric acid is 15 wt %.

[0026] As a further technical solution, when the pickling solution includes sulfuric acid, the concentration of the sulfuric acid is 20 wt %.

[0027] As a further technical solution, the pickling temperature is 40-50° C., and the pickling time is 20-30 minutes.

[0028] As a further technical solution, the components of the plating flux include zinc chloride, nickel chloride, ammonium chloride and water in a mass volume ratio of 90g:30g:20g:1~1.2L; and / or, The assist plating temperature is 60-70° C., and the assist plating time is 20-30 minutes.

[0029] As a further technical solution, during the galvanizing, the galvanizing liquid is zinc liquid; and / or, The galvanizing temperature is 450-500° C., and the galvanizing time is 4-5 minutes.

[0030] As a further technical solution, the passivation temperature is 40-50° C., and the passivation time is 7-10 minutes.

[0031] The present invention also provides a method for preparing a high-conductivity steel-core aluminum stranded wire for overhead use, comprising the following steps: The aluminum wire is twisted in two layers on the surface of the galvanized steel core to obtain a high-conductivity steel-core aluminum stranded wire for overhead use.

[0032] As a further technical solution, the aluminum wire is a nickel-phosphorus alloy-plated aluminum wire.

[0033] As a further technical solution, the method for preparing the nickel-phosphorus alloy-plated aluminum wire comprises the following steps: The aluminum wire is alkali washed, pickled, plated with nickel-phosphorus alloy, and dried to obtain nickel-phosphorus alloy plated aluminum wire.

[0034] As a further technical solution, during the alkali washing, the alkali washing solution is a 10wt% sodium hydroxide aqueous solution.

[0035] As a further technical solution, the temperature of the alkali washing is 50-60° C., and the time of the alkali washing is 10-15 minutes.

[0036] As a further technical solution, during the pickling, the pickling liquid is 15wt% HCl.

[0037] As a further technical solution, the pickling temperature is 40-50° C., and the pickling time is 3-5 minutes.

[0038] As a further technical solution, when plating nickel-phosphorus alloy, the components of the nickel-phosphorus alloy liquid include nickel sulfate, sodium hypophosphite, citric acid, sodium tartrate, potassium iodate, sodium dodecylbenzenesulfonate, nano-graphite powder and water in a mass volume ratio of 25g:30g:15g:10g:0.05mg:0.05mg:8g:1~1.2L.

[0039] As a further technical solution, the pH value of the nickel-phosphorus alloy liquid is 5.

[0040] As a further technical solution, the temperature of the nickel-phosphorus alloy plating is 70-80° C., and the time is 2-4 hours.

[0041] As a further technical solution, the number of the aluminum wires is 26-30.

[0042] The working principle and beneficial effects of the present invention are: In the present invention, a passivation treatment is performed after galvanizing, using a water-based acrylic resin, nickel nitrate, sodium carboxymethyl cellulose, sodium dodecyl sulfate, and 5-carboxyl-2,3-diaminopyridine-functionalized single-walled carbon nanotubes as a passivation solution to improve the corrosion resistance of galvanized steel strands. To address the problem of insufficient density of the passivation film formed by traditional passivation solutions in the prior art, resulting in poor corrosion resistance of the galvanized steel core, the present invention adds 5-carboxyl-2,3-diaminopyridine-functionalized single-walled carbon nanotubes to the passivation solution. The combination of 5-carboxyl-2,3-diaminopyridine and the single-walled carbon nanotubes effectively improves the dispersion of the carbon nanotubes in water, prevents agglomeration, and increases the density of the passivation film formed by the passivation solution, thereby achieving the effect of improving the corrosion resistance of the galvanized steel core, thereby imparting long-term corrosion resistance to the steel core. DETAILED DESCRIPTION

[0043] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0044] In the following examples and comparative examples: Water-based acrylic resin, model: Joncryl 678; sodium carboxymethyl cellulose, model: FH9; 5-carboxy-2,3-diaminopyridine, model: PVP K15; polyacrylic acid, weight-average molecular weight: 10,000; single-walled carbon nanotubes, diameter: 1-2 nm, length: 10-30 μm; nanographite powder: 50 nm; The components of the plating flux include zinc chloride, nickel chloride, ammonium chloride and water in a mass volume ratio of 90g:30g:20g:1L; The components of the nickel-phosphorus alloy liquid include nickel sulfate, sodium hypophosphite, citric acid, sodium tartrate, potassium iodate, sodium dodecylbenzenesulfonate, nanographite powder and water in a mass volume ratio of 25g:30g:15g:10g:0.05mg:0.05mg:8g:1L, and the pH is 5; The raw materials of the galvanizing solution include: zinc solution with a purity of 99.5%.

[0045] Example 1 The preparation method of a galvanized steel core comprises the following steps: immersing a steel wire in an 8wt% sodium hydroxide aqueous solution for alkali washing at a temperature of 70°C for 40 minutes; after alkali washing, immersing the steel wire in a 15wt% HCl aqueous solution for pickling at a temperature of 40°C for 30 minutes; after pickling, adding a plating flux and performing plating flux at 60°C for 30 minutes; then placing the steel core after the plating flux into a galvanizing solution and galvanizing at 450°C for 5 minutes; immersing the galvanized steel core in a passivation solution and passivating at 40°C for 10 minutes, and drying and twisting the passivated steel core to obtain a galvanized steel core; The passivation solution raw materials are composed of: 15wt% water-based acrylic resin, 10wt% nickel nitrate, 3wt% sodium carboxymethyl cellulose, 0.5wt% sodium dodecyl sulfate, 5wt% functionalized single-walled carbon nanotubes, and the balance is water; Preparation method of functionalized single-walled carbon nanotubes: A1. Add 50 g of single-walled carbon nanotubes to 500 mL of 28 wt % sulfuric acid, heat to 70°C, and stir for 10 hours. Then, lower the reaction temperature to 25°C, add 50 mL of 68 wt % nitric acid, and stir at 25°C for 24 hours. Wash with water, and dry to obtain pretreated carbon nanotubes. A2. The obtained pretreated carbon nanotubes and 0.8 g of 5-carboxyl-2,3-diaminopyridine were added to 500 mL of dimethyl sulfoxide, stirred at 40° C. for 4 h, and dried to obtain functionalized single-walled carbon nanotubes; The preparation method of nickel-phosphorus alloy-plated aluminum wire comprises the following steps: soaking the aluminum wire in a 10wt% sodium hydroxide aqueous solution at 50°C for 15 minutes, removing the aluminum wire, and then soaking it in 15wt% HCl at 40°C for 5 minutes. After removing the aluminum wire, immersing it in a nickel-phosphorus alloy solution at 70°C for 4 hours, and then removing the aluminum wire and drying it to obtain the nickel-phosphorus alloy-plated aluminum wire; A method for preparing a high-conductivity steel core aluminum stranded wire for overhead use comprises the following steps: twisting 26 nickel-phosphorus alloy-plated aluminum wires in two layers on the surface of a galvanized steel core to obtain the high-conductivity steel core aluminum stranded wire for overhead use.

[0046] Example 2 The preparation method of a galvanized steel core comprises the following steps: immersing a steel wire in a 9wt% sodium hydroxide aqueous solution for alkali washing at a temperature of 75°C for 35 minutes; after alkali washing, immersing the steel wire in a 15wt% HCl aqueous solution for pickling at a temperature of 45°C for 25 minutes; after pickling, adding a plating flux and performing a plating flux at 65°C for 25 minutes; then placing the steel core after the plating flux into a galvanizing solution and galvanizing at 480°C for 5 minutes; immersing the galvanized steel core in a passivation solution and passivating at 45°C for 9 minutes, and drying and twisting the passivated steel core to obtain a galvanized steel core; The passivation solution raw materials are composed of: 17wt% water-based acrylic resin, 13wt% nickel nitrate, 6wt% sodium carboxymethyl cellulose, 0.7wt% sodium dodecyl sulfate, 7wt% functionalized single-walled carbon nanotubes, and the balance is water; Preparation method of functionalized single-walled carbon nanotubes: A1. Add 50 g of single-walled carbon nanotubes to 500 mL of 28 wt % sulfuric acid, heat to 75°C, and stir for 8 hours. Then, lower the reaction temperature to 25°C, add 50 mL of 68 wt % nitric acid, and stir at 25°C for 24 hours. Wash with water, and dry to obtain pretreated carbon nanotubes. A2. The obtained pretreated carbon nanotubes and 0.8 g of 5-carboxyl-2,3-diaminopyridine were added to 500 mL of dimethyl sulfoxide, stirred at 50° C. for 3 h, and dried to obtain functionalized single-walled carbon nanotubes; The preparation method of nickel-phosphorus alloy-plated aluminum wire comprises the following steps: soaking the aluminum wire in a 10wt% sodium hydroxide aqueous solution at 55°C for 13 minutes, removing the aluminum wire, and then soaking it in 15wt% HCl at 45°C for 4 minutes. After removing the aluminum wire, immersing it in a nickel-phosphorus alloy solution at 75°C for 3 hours, and then removing the aluminum wire and drying it to obtain the nickel-phosphorus alloy-plated aluminum wire; A method for preparing a high-conductivity steel core aluminum stranded wire for overhead use comprises the following steps: twisting 28 nickel-phosphorus alloy-plated aluminum wires in two layers on the surface of a galvanized steel core to obtain the high-conductivity steel core aluminum stranded wire for overhead use.

[0047] Example 3 The preparation method of a galvanized steel core comprises the following steps: immersing a steel wire in a 10wt% sodium hydroxide aqueous solution for alkali washing at a temperature of 80°C for 30 minutes; after alkali washing, immersing the steel wire in a 15wt% HCl aqueous solution for pickling at a temperature of 50°C for 20 minutes; after pickling, adding a plating flux and performing plating flux at 70°C for 20 minutes; then placing the steel core after the plating flux into a galvanizing solution and galvanizing at 500°C for 4 minutes; immersing the galvanized steel core in a passivation solution and passivating at 50°C for 7 minutes; drying and twisting the passivated steel core to obtain a galvanized steel core; The passivation solution raw materials are composed of: 20wt% water-based acrylic resin, 15wt% nickel nitrate, 8wt% sodium carboxymethyl cellulose, 1wt% sodium dodecyl sulfate, 10wt% functionalized single-walled carbon nanotubes, and the balance is water; Preparation method of functionalized single-walled carbon nanotubes: A1. Add 50 g of single-walled carbon nanotubes to 500 mL of 28 wt % sulfuric acid, heat to 80°C, and stir for 6 hours. Then, lower the reaction temperature to 30°C, add 50 mL of 68 wt % nitric acid, and stir at 30°C for 20 hours. Wash with water, and dry to obtain pretreated carbon nanotubes. A2. The obtained pretreated carbon nanotubes and 0.8 g of 5-carboxyl-2,3-diaminopyridine were added to 500 mL of dimethyl sulfoxide, stirred at 60° C. for 2 h, and dried to obtain functionalized single-walled carbon nanotubes; The preparation method of nickel-phosphorus alloy-plated aluminum wire comprises the following steps: soaking the aluminum wire in a 10wt% sodium hydroxide aqueous solution at 60°C for 10 minutes, removing the aluminum wire, and then soaking the aluminum wire in 15wt% HCl at 50°C for 3 minutes. After removing the aluminum wire, soaking the aluminum wire in a nickel-phosphorus alloy solution at 80°C for 2 hours, and then removing the aluminum wire and drying the solution to obtain the nickel-phosphorus alloy-plated aluminum wire. A method for preparing a high-conductivity steel core aluminum stranded wire for overhead use comprises the following steps: 30 nickel-phosphorus alloy-plated aluminum wires are twisted in two layers on the surface of a galvanized steel core to obtain the high-conductivity steel core aluminum stranded wire for overhead use.

[0048] Example 4 The only difference between this embodiment and embodiment 2 is that the amount of 5-carboxy-2,3-diaminopyridine added is 8 g.

[0049] Example 5 The only difference between this embodiment and embodiment 2 is that the amount of 5-carboxy-2,3-diaminopyridine added is 1 g.

[0050] Example 6 The only difference between this embodiment and embodiment 2 is that the amount of 5-carboxy-2,3-diaminopyridine added is 3 g.

[0051] Example 7 The only difference between this embodiment and embodiment 2 is that the amount of 5-carboxy-2,3-diaminopyridine added is 5 g.

[0052] Example 8 The only difference between this embodiment and embodiment 6 is that the preparation method of functionalized single-walled carbon nanotubes is as follows: A1, 50 g of single-walled carbon nanotubes are added to 500 mL of 28 wt % sulfuric acid, the temperature is raised to 75° C., and the mixture is stirred for 8 h. Then, the reaction temperature is lowered to 25° C., 50 mL of 68 wt % nitric acid is added, and the mixture is stirred at 25° C. for 24 h. The mixture is washed with water and dried to obtain pretreated carbon nanotubes; A2. The obtained pretreated carbon nanotubes, 3 g of 5-carboxyl-2,3-diaminopyridine, and 0.5 g of polyacrylic acid were added to 500 mL of water, stirred at 50° C. for 3 h, and dried to obtain functionalized single-walled carbon nanotubes.

[0053] Example 9 The only difference between this embodiment and embodiment 8 is that the amount of polyacrylic acid added is 3 g.

[0054] Example 10 The only difference between this embodiment and embodiment 8 is that the amount of polyacrylic acid added is 1 g.

[0055] Example 11 The only difference between this embodiment and embodiment 8 is that the amount of polyacrylic acid added is 2 g.

[0056] Comparative Example 1 The only difference between this comparative example and Example 1 is the preparation method of functionalized single-walled carbon nanotubes: 50 g of single-walled carbon nanotubes were added to 500 mL of 28 wt % sulfuric acid, the temperature was raised to 70° C. and stirred for 10 h, then the reaction temperature was lowered to 25° C., 50 mL of 68 wt % nitric acid was added, and the mixture was stirred at 25° C. for 24 h. Functionalized single-walled carbon nanotubes were obtained by washing with water and drying.

[0057] Comparative Example 2 The only difference between this comparative example and Example 1 is that the functionalized single-walled carbon nanotubes are replaced with an equal amount of single-walled carbon nanotubes.

[0058] Comparative Example 3 The only difference between this comparative example and Example 1 is that no functionalized single-walled carbon nanotubes are added.

[0059] Experimental Example 1 The galvanized steel cores prepared in Examples 1 to 11 and Comparative Examples 1 to 3 were tested according to the neutral salt spray test standard in GB / T 10125-2021 "Artificial Salt Spray Corrosion Test Method". The spray was a 5 wt% NaCl aqueous solution at a temperature of 35°C. The spray was carried out for 15 minutes at intervals of 15 minutes. The corrosion of the sample surface was observed and the time when corrosion began to appear on the sample surface was recorded. The test results are shown in Table 1.

[0060] Table 1 Corrosion resistance test results of galvanized steel core

[0061] As can be seen from Table 1, the salt spray resistance time of the galvanized steel cores prepared in Examples 1 to 11 is longer than that of Comparative Examples 1 to 3, indicating that the addition of functionalized single-walled carbon nanotubes prepared from single-walled carbon nanotubes and 5-carboxyl-2,3-diaminopyridine to the passivation solution can improve the corrosion resistance of the galvanized steel core, thereby improving the corrosion resistance of the steel-core aluminum stranded wire.

[0062] Experimental Example 2 The nickel-phosphorus alloy-plated aluminum wires prepared in Examples 1 to 3 were tested for DC resistivity at 20° C. according to the method in GB / T 3048.4-2007 “Test methods for electrical properties of wires and cables - Part 2: Resistivity test for metallic materials”. The test results are shown in Table 2.

[0063] Table 2 Test results of resistivity of nickel-phosphorus alloy-plated aluminum wire

[0064] As shown in Table 2, the resistivity of the nickel-phosphorus alloy aluminum wires prepared in Examples 1 to 3 is lower than 0.0280Ω·mm 2 / m, indicating that the nickel-phosphorus alloy-plated aluminum wire provided by the present invention has high electrical conductivity, thereby providing a high-conductivity steel-core aluminum stranded wire for overhead use.

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high conductivity steel core aluminum stranded wire for overhead use, characterized in that: The invention relates to a galvanized steel core and aluminum wires twisted on the surface of the galvanized steel core, wherein the galvanized steel core is formed by twisting 19 steel wires, and the aluminum wires are divided into two layers and twisted on the outside of the galvanized steel core. The preparation method of the galvanized steel core comprises the following steps: galvanizing the steel wires, adding them into a passivation solution for passivation, drying them, and twisting them to obtain the galvanized steel core; the raw materials of the passivation solution are composed of the following components by weight: 15%-20% water-based acrylic resin, 10%-15% nickel nitrate, 3%-8% sodium carboxymethyl cellulose, 0.5%-1% sodium dodecyl sulfate, 5%-10% functionalized single-walled carbon nanotubes, and the balance is water; the raw materials of the functionalized single-walled carbon nanotubes include single-walled carbon nanotubes, polyacrylic acid, and 5-carboxyl-2,3-diaminopyridine; the mass ratio of the single-walled carbon nanotubes to 5-carboxyl-2,3-diaminopyridine is 50:3; and the mass ratio of the single-walled carbon nanotubes to the polyacrylic acid is 50:1-2.

2. The overhead high-conductivity steel-core aluminum stranded wire according to claim 1, characterized in that: The method for preparing functionalized single-walled carbon nanotubes comprises the following steps: A1. adding single-walled carbon nanotubes to sulfuric acid for a first mixing, adding nitric acid for a second mixing, and drying to obtain pretreated carbon nanotubes; A2. Add the pretreated carbon nanotubes, 5-carboxyl-2,3-diaminopyridine, and polyacrylic acid into water and mix for the third time, and then dry to obtain functionalized carbon nanotubes.

3. The overhead high-conductivity steel-core aluminum stranded wire according to claim 1, characterized in that: The galvanizing step also includes alkali washing, pickling and plating assistance. During the alkali washing, the alkali washing solution is a sodium hydroxide aqueous solution; and / or, The alkali washing temperature is 70-80°C and the alkali washing time is 30-40 minutes; and / or, During the pickling, the pickling solution includes one or both of hydrochloric acid and sulfuric acid; and / or, The pickling temperature is 40-50° C., and the pickling time is 20-30 minutes.

4. The overhead high-conductivity steel-core aluminum stranded wire according to claim 3, characterized in that: During the plating assist, the components of the plating assist agent include zinc chloride, nickel chloride, ammonium chloride and water in a mass volume ratio of 90g:30g:20g:1-1.2L; and / or, The assist plating temperature is 60-70° C., and the assist plating time is 20-30 minutes.

5. The overhead high-conductivity steel-core aluminum stranded wire according to claim 1, characterized in that: During the galvanizing, the galvanizing solution is zinc solution; and / or, The galvanizing temperature is 450-500° C., and the galvanizing time is 4-5 minutes.

6. The overhead high-conductivity steel-core aluminum stranded wire according to claim 1, characterized in that: The passivation temperature is 40-50° C., and the passivation time is 7-10 minutes.

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