Rat-proof, ant-proof and salt-fog-resistant special power cable

Abstract

The invention relates to the technical field of power cables, in particular to a special power cable capable of preventing rats and ants and resisting salt mist. The cable comprises a conductor, and the conductor is prepared through the following mode that the conductor is composed of, by weight, more than or equal to 99.5% of copper, 0.2%-0.5% of silver and 0.1%-0.3% of rare earth elements; wherein the copper adopts a T2 oxygen-free copper rod with the purity of 99.95% or above, the silver adopts 99.99% high-purity silver particles, the rare earth adopts a rare earth intermediate alloy, the rare earth content of the rare earth intermediate alloy is 20%-30%, and the rare earth intermediate alloy is a copper-lanthanum alloy or a copper-cerium alloy; the components of the conductor are mixed and prepared into drawn wires; a nickel-phosphorus alloy layer is chemically plated on the surface of the conductor, and the cable can stably operate in various severe environments, has excellent rat and ant resistance, salt mist resistance, chemical erosion resistance and the like, remarkably prolongs the service life of the cable in the severe environments, remarkably improves the reliability of power transmission in the severe environments, and reduces the maintenance cost and the risk of power supply interruption.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, and in particular to a special power cable that is rodent-proof, ant-proof, and salt spray-resistant. Background Technology

[0002] In modern society, the stability of power supply is crucial. However, in certain special areas, such as coastal industrial zones, wetland mining areas, and chemically polluted areas, power cables face numerous severe challenges. Besides common problems like rodent and insect damage and salt spray corrosion, they may also suffer from chemical corrosion, ultraviolet aging, and mechanical damage. Traditional cables experience a significantly shortened lifespan in these harsh environments. For example, in coastal areas, chloride ions in salt spray gradually corrode the metal components of the cable, leading to decreased conductivity and increased short-circuit risk; in chemical industrial parks, various chemical gases and liquids may penetrate into the cable, damaging the insulation layer and causing safety hazards. Moreover, rodent and insect gnawing can directly damage the cable structure, causing power transmission interruptions. Frequent cable failures not only increase maintenance costs but also seriously affect normal production and daily life in the affected areas. Therefore, the development of a special power cable capable of comprehensively coping with multiple harsh environmental factors is urgently needed. Summary of the Invention

[0003] To overcome the problems existing in related technologies, the present invention provides a rodent-proof and salt spray-resistant special power cable. This cable has excellent resistance to rodents and ants, salt spray, and chemical corrosion, which significantly improves the service life of the cable and the reliability of power transmission in harsh environments.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A rodent- and ant-resistant, salt spray-resistant special power cable is provided, characterized in that it includes a conductor, said conductor being manufactured by the following method:

[0006] The conductor is composed of the following components by weight percentage:

[0007] Copper content ≥ 99.5%

[0008] Silver content 0.2%-0.5%,

[0009] Rare earth element content: 0.1%-0.3%;

[0010] Among them, the copper uses T2 oxygen-free copper rod with a purity of 99.95% or higher, the silver uses 99.99% high-purity silver particles, and the rare earth uses rare earth intermediate alloy. The rare earth content of the rare earth intermediate alloy is 20%-30%, and the rare earth intermediate alloy is a copper-lanthanum alloy or a copper-cerium alloy.

[0011] The components of the conductor are mixed and prepared into a wire;

[0012] The surface of the conductor is chemically plated with a nickel-phosphorus alloy layer, the composition of which is shown in the table below:

[0013] Element content <![CDATA[Nickel sulfate (NiSO4·6H2O)]]> 25-30g / L <![CDATA[Sodium hypophosphite (NaH2PO2·H2O)]]> 20-25g / L <![CDATA[Sodium acetate (CH3COONa·3H2O)]]> 15-20g / L <![CDATA[Sodium citrate (Na3C6H5O7·2H2O)]]> 10-15g / L <![CDATA[Lactic acid (C3H6O3)]]> 10-15ml / L stabilizer 22-10ml / L

[0014] In this invention, the conductor material is a copper-silver-rare earth alloy. Copper ensures good conductivity, silver further reduces resistance and improves conductivity, while rare earth elements enhance the conductor's mechanical strength and corrosion resistance. The conductor surface is treated with a chemical nickel-phosphorus alloy plating process to form a dense protective film, which has several times the corrosion resistance of ordinary tin plating and can effectively resist the erosion of salt spray and chemicals, ensuring stable power transmission.

[0015] Furthermore, the step of mixing the conductor components and preparing them into a wire includes:

[0016] Step 1: Raw material cleaning

[0017] The copper rod is cut into small segments of 5-10cm in length. The silver particles are sieved to remove impurities. The rare earth intermediate alloy is crushed into particles with a diameter of ≤2cm. Then, the copper rod, silver particles and rare earth intermediate alloy are placed in an ultrasonic cleaner and cleaned with 5% dilute sulfuric acid solution for 10-15 minutes to remove the surface oxide layer, oil and dust. Then, they are rinsed three times with deionized water and finally placed in a vacuum drying oven at 120℃ for 2 hours.

[0018] Segmented melting and composition adjustment

[0019] Phase 1: Copper rod smelting: A medium-frequency induction melting furnace is used. The pre-treated copper segments are first put into the crucible, which is a graphite crucible. Before use, it is preheated at 800℃ for 2 hours to remove moisture. Inert gas is introduced for protection to prevent copper oxidation. The temperature is raised to the melting point of copper, 1083℃, and held for 30 minutes to completely melt the copper and form molten copper. During this period, the copper is slowly stirred with a graphite stirring rod. At the same time, the surface of the molten copper is observed. If oxide slag appears, it is gently removed with a graphite spoon.

[0020] Phase Two: Silver Addition and Dissolution

[0021] After the copper liquid stabilizes, the pretreated silver particles are slowly added to the copper liquid in 3-5 batches, with an interval of 5 minutes between each batch. The liquid is then kept warm for another 20 minutes, with the temperature controlled at 1100-1150℃. Taking advantage of the good miscibility between silver and copper, the silver is completely dissolved in the copper liquid. At this point, a sample is taken, and the silver content in the alloy is detected by a direct-reading spectrometer. If the preset value is not reached, silver particles are added until the silver content meets the requirements, thus obtaining a copper-silver alloy liquid.

[0022] The third stage: rare earth addition and refining: the rare earth intermediate alloy is slowly added to the copper-silver alloy liquid, the temperature is controlled at 1150-1200℃, and the temperature is held for 25-30 minutes. A mixture of borax and sodium carbonate is added at a rate of 0.5%-1% of the alloy liquid mass. After standing for 15 minutes, the surface slag is removed with a graphite spoon, and the rare earth content is tested again to ensure that it is within the range of 0.1%-0.3%.

[0023] Step 2: Ingot Forming

[0024] Mold pretreatment: Select a steel mold, apply graphite lubricant (a mixture of graphite powder and alcohol in a 1:3 ratio) to the inner wall of the mold, and then preheat it in an oven at 200-250℃ for 1 hour to prevent the alloy liquid from sticking to the mold when it cools.

[0025] Casting and Cooling: The refined copper-silver-rare earth alloy liquid is slowly poured into the preheated mold at a flow rate of 5-8 kg / min at a temperature of 1150-1200℃. After casting, the mold is placed in a slow cooling pit, which is lined with heat insulation cotton and the temperature is maintained at 300-400℃. The mold is cooled with the furnace for 24 hours. After cooling, the mold is demolded to obtain a copper-silver-rare earth alloy ingot. The surface of the ingot should be free of defects such as cracks, pores, and inclusions. Otherwise, it needs to be remelted.

[0026] Step 3: Ingot Pretreatment

[0027] Ingot straightening and cutting: A hydraulic straightening machine is used to straighten the alloy ingots, ensuring that the straightness error of the ingots is ≤0.5mm / m. Then, a saw is used to cut the ingots into billets with a length of 1-1.5m. The cut surfaces must be flat, and the perpendicularity error must be ≤1°.

[0028] The cut billet is placed in a centerless grinder for surface polishing to remove oxide scale, burrs, and defects from the ingot surface, achieving a surface roughness Ra ≤ 1.6μm. Multi-pass wire drawing is then performed, with the number of drawing passes designed according to the final conductor specifications. A diamond drawing die is used for each pass.

[0029] First wire drawing: One end of the pretreated billet is upset using a cold heading machine, making the tip diameter 1-2 mm smaller than the diameter of the first die hole. It is then introduced into a continuous wire drawing machine. During the wire drawing process, an emulsion is used, consisting of the following weight percentages: water 90%, mineral oil 5%, extreme pressure agent 3%, and rust inhibitor 2%. This emulsion is used for cooling and lubrication. The emulsion temperature is controlled at 30-40℃, and the pressure at 0.3-0.5 MPa.

[0030] Intermediate drawing passes: After the first drawing pass is completed, the wire enters the subsequent drawing passes. The traction speed of each pass gradually increases as the wire diameter decreases, while the emulsion parameters remain constant. After every 3 drawing passes, the surface of the wire must be inspected. If surface scratches, cracks, or other defects are found, the die must be replaced or the drawing parameters adjusted.

[0031] Final wire drawing: The diameter of the final wire drawing die must be precisely matched to the conductor design specifications. During wire drawing, the traction tension must be controlled to be stable. The wire diameter is detected in real time using an online diameter measuring instrument to ensure that it meets the requirements.

[0032] Furthermore, the step of chemically plating a nickel-phosphorus alloy layer onto the surface of the conductor includes: a conductor chemical plating nickel-phosphorus alloy treatment process.

[0033] Step 1: Conductor pretreatment

[0034] Degreasing and oil removal: Place the drawn conductor wire into a degreasing tank containing an alkaline degreasing agent. The alkaline degreasing agent consists of 50g / L sodium hydroxide, 30g / L sodium carbonate, 20g / L sodium phosphate, and 5g / L surfactant. The solution temperature is 50-60℃. Soak for 15-20 minutes. After degreasing, rinse the wire in a deionized water tank three times for 5 minutes each time until the surface pH value is neutral.

[0035] Pickling and rust removal: Place the degreased wire into the pickling tank. The pickling solution is a 10% dilute sulfuric acid solution. The temperature is 25-30℃. Soak for 5-8 minutes to remove the oxide film on the conductor surface. During the pickling process, the wire needs to be turned over regularly. After pickling, immediately rinse with deionized water 3 times, 5 minutes each time. Then, neutralize in a 5% sodium carbonate solution for 2 minutes. Rinse with deionized water until neutral. Finally, dry in a 120℃ oven for 10 minutes.

[0036] Step 2: Preparation of electroless nickel-phosphorus alloy plating solution

[0037] Add 50L of deionized water to a 100L mixing tank and heat to 40-50℃. Add nickel sulfate, sodium hypophosphite, sodium acetate, and sodium citrate in sequence. After each reagent is added, stir for 15 minutes to ensure that the reagent is completely dissolved and no precipitate is formed. Slowly add lactic acid to the base solution and stir for 10 minutes. Then add stabilizer and brightener and continue stirring for 20 minutes to make the composition of the plating solution uniform. Adjust the pH of the plating solution to 4.5-5.0 with 10% sodium hydroxide solution or 10% sulfuric acid solution. Then add deionized water to make up to 100L. Stir for 30 minutes and let stand for 1 hour. Filter to remove tiny impurities from the plating solution to obtain a clear electroless nickel-phosphorus alloy plating solution.

[0038] Step 3: Chemical Plating Process Control

[0039] The prepared electroless nickel-phosphorus alloy plating solution is injected into the electroless plating tank. The temperature of the plating solution is controlled at 85-90℃ using a water bath heating method. At the same time, compressed air is introduced to stir the plating solution to ensure uniform temperature and consistent composition. The pretreated conductor wire is introduced into the plating tank through a wire feeding rack. The continuous plating method is adopted, and the residence time of the wire in the plating solution is controlled to be 25-30 minutes. The sodium hypophosphite in the plating solution decomposes at 85-90℃ to produce phosphorus, which is deposited on the conductor surface together with nickel ions to form a nickel-phosphorus alloy layer.

[0040] Furthermore, the thickness of the nickel-phosphorus alloy layer is 7 μm ± 0.5 μm.

[0041] Furthermore, the conductor is covered from the inside out with an insulating layer, a shielding layer, a rodent-resistant layer, a salt spray and chemical corrosion resistant layer, and a mechanical protection and anti-aging layer.

[0042] The synergistic effect of the various materials effectively resists various harsh environmental factors, greatly extending the service life of the cable and reducing maintenance and replacement costs.

[0043] Furthermore, the insulating layer is a composite insulating material of polyether ether ketone and nano boron nitride.

[0044] Polyetheretherketone (PEEK) possesses excellent heat resistance, chemical stability, and mechanical properties. Nano-boron nitride is uniformly dispersed within the PEEK, forming a highly efficient thermally conductive and insulating network. On one hand, this improves the thermal conductivity of the insulation layer, aiding in cable heat dissipation; on the other hand, it enhances the insulation layer's resistance to salt spray, chemical corrosion, and corona discharge. During the insulation layer manufacturing process, an appropriate amount of UV absorber is added to effectively prevent UV aging and damage to the insulation layer. The insulation layer thickness is precisely controlled within a specific range according to the cable voltage rating, ensuring reliable insulation performance.

[0045] Furthermore, the shielding layer includes an inner shielding layer and an outer shielding layer, wherein the inner shielding layer is wrapped with amorphous alloy strip, and the outer shielding layer is a silver-plated copper wire braided mesh.

[0046] The inner layer is wrapped with amorphous alloy strip with high magnetic permeability, which can effectively shield low-frequency electromagnetic interference; the outer layer is a silver-plated copper wire braided mesh, which has a good shielding effect against high-frequency electromagnetic interference. A graphene-modified semi-conductive buffer layer is set between the two shielding layers. The high conductivity and large specific surface area of ​​graphene enable it to more effectively and uniformly distribute the electric field, suppress partial discharge, and protect the insulation layer from damage.

[0047] Furthermore, the anti-rodent layer is made of a thermoplastic elastomer containing peppermint oil and silicone flame retardant.

[0048] The scents released by natural plant extracts have a strong repellent effect on rodents and ants. Organosilicon flame retardants not only improve the flame retardant properties of the material but also enhance its resistance to chemical corrosion. The rodent-repellent layer utilizes a special extrusion process to create a micro-protruding structure on its surface, increasing the difficulty for rodents and ants to bite through it, further improving the rodent-repellent effect. It is also environmentally friendly, avoiding the pollution problems that may arise from traditional rodent-repellent additives, while the organosilicon flame retardants improve the safety of the cable.

[0049] Furthermore, the salt spray resistant and chemical corrosion resistant layer adopts a three-layer composite structure, with the inner layer being a polytetrafluoroethylene layer, the middle layer being an aramid fiber reinforced ethylene-tetrafluoroethylene copolymer layer, and the outer layer being a nano-silica modified fluorocarbon coating.

[0050] The inner layer is a polytetrafluoroethylene (PTFE) layer, which has an extremely low coefficient of friction, excellent chemical stability, and resistance to salt spray corrosion, effectively blocking the penetration of chemicals and salt spray. The middle layer is an aramid fiber-reinforced ethylene-tetrafluoroethylene copolymer (ETFE) layer, where aramid fibers enhance the material's mechanical strength, and ETFE has good weather resistance, chemical corrosion resistance, and electrical properties. The outer layer is a nano-silica modified fluorocarbon coating, where nano-silica improves the coating's hardness and wear resistance, while the fluorocarbon coating provides excellent resistance to salt spray, ultraviolet radiation, and self-cleaning properties.

[0051] Furthermore, the mechanical protection and anti-aging layer is made of a polyurethane and carbon fiber composite material.

[0052] Carbon fiber significantly enhances the material's mechanical strength and rigidity, enabling the cable to withstand greater tensile, compressive, and bending forces; polyurethane (PU) possesses excellent weather resistance, abrasion resistance, and UV aging resistance. Adding appropriate amounts of antioxidants and light stabilizers to the material further improves its anti-aging properties, protecting the cable's internal structure from external physical damage and environmental factors.

[0053] The beneficial effects of this invention are as follows:

[0054] This invention produces a conductor from copper-silver-rare earth alloy raw materials, and then chemically plating the conductor with nickel-phosphorus alloy. Strict control of plating bath composition, temperature, time, and other process parameters ensures uniform thickness of the nickel-phosphorus alloy layer. The conductor uses high-purity raw materials, including T2 oxygen-free copper rods (purity above 99.95%), 99.99% high-purity silver particles, and rare earth intermediate alloys such as copper-lanthanum alloy and copper-cerium alloy, with a rare earth content of 20%-30%. This avoids excessive burn-off caused by directly adding pure rare earth. A uniform and dense nickel-phosphorus alloy layer is formed on the conductor surface, significantly improving the conductor's resistance to salt spray and chemical corrosion, giving the cable high resistance to rodents and salt spray. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the structure of a rodent-proof, ant-proof, and salt-spray-resistant special power cable according to a specific embodiment of the present invention.

[0056] 1. Conductor; 2. Insulation layer; 3. Shielding layer; 4. Anti-rodent and anti-termite layer; 5. Salt spray and chemical corrosion resistant layer; 6. Mechanical protection and anti-aging layer. Detailed Implementation

[0057] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0058] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0059] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0060] Example

[0061] Please see Figure 1 This embodiment discloses a rodent-proof, salt spray-resistant special power cable, including a conductor 1, which is manufactured by the following method:

[0062] The conductor 1 is composed of the following components by weight percentage:

[0063] Copper content ≥ 99.5%

[0064] Silver content 0.2%-0.5%,

[0065] Rare earth element content: 0.1%-0.3%;

[0066] Among them, the copper uses T2 oxygen-free copper rod with a purity of 99.95% or higher, the silver uses 99.99% high-purity silver particles, and the rare earth uses rare earth intermediate alloy. The rare earth content of the rare earth intermediate alloy is 20%-30%, and the rare earth intermediate alloy is a copper-lanthanum alloy or a copper-cerium alloy.

[0067] The components of conductor 1 are mixed and prepared into a drawn wire;

[0068] The surface of conductor 1 is chemically plated with a nickel-phosphorus alloy layer, the composition of which is shown in the table below:

[0069] Element content <![CDATA[Nickel sulfate (NiSO4·6H2O)]]> 25-30g / L <![CDATA[Sodium hypophosphite (NaH2PO2·H2O)]]> 20-25g / L <![CDATA[Sodium acetate (CH3COONa·3H2O)]]> 15-20g / L <![CDATA[Sodium citrate (Na3C6H5O7·2H2O)]]> 10-15g / L <![CDATA[Lactic acid (C3H6O3)]]> 10-15ml / L stabilizer 22-10ml / L

[0070] In this invention, nickel sulfate provides nickel ions, which are the main nickel source for forming the nickel-phosphorus alloy coating; sodium hypophosphite acts as a reducing agent, providing electrons during the electroless plating process to reduce nickel ions to nickel metal, while phosphorus deposition occurs simultaneously; sodium acetate acts as a buffer, maintaining the pH value of the plating solution and ensuring the smooth progress of the electroless plating reaction; sodium citrate acts as a complexing agent, forming a stable complex with nickel ions to prevent premature precipitation of nickel ions in the plating solution and controlling the release rate of nickel ions; lactic acid acts as a complexing agent and a buffer, helping to improve the stability of the plating solution and the quality of the coating; stabilizers can inhibit the self-decomposition of the plating solution and extend its service life; and brighteners can make the coating surface brighter and smoother.

[0071] In this invention, conductor 1 is made of copper-silver-rare earth alloy. Specifically, the copper-silver-rare earth alloy raw material is processed into conductor 1 of the required specifications through processes such as smelting and wire drawing. Then, conductor 1 is subjected to chemical nickel-phosphorus alloy plating. The process parameters such as plating solution composition, temperature, and time are strictly controlled to ensure that the thickness of the nickel-phosphorus alloy plating layer is uniform and controlled at about 7μm.

[0072] I. Copper-Silver-Rare Earth Alloy Smelting Process

[0073] This process aims at "precise control of composition, efficient removal of impurities, and uniform and refined microstructure." Through multi-stage melting and refining, it ensures that the alloy raw materials meet the requirements of subsequent processing. The specific steps are as follows:

[0074] 1. Raw material pretreatment

[0075] Raw material selection and proportioning: High-purity raw materials are selected according to the preset composition ratio of copper-silver-rare earth alloy (usually copper content ≥99.5%, silver content 0.2%-0.5%, and rare earth element (such as lanthanum, cerium) content 0.1%-0.3%). Among them, T2 oxygen-free copper rods (purity above 99.95%) are used for copper, 99.99% high-purity silver granules are used for silver, and rare earth intermediate alloys (such as copper-lanthanum alloy, copper-cerium alloy, rare earth content 20%-30%) are used to avoid excessive burn-off rate caused by directly adding pure rare earth.

[0076] Raw material cleaning: Cut the copper rod into small segments of 5-10cm in length, sieve the silver granules to remove impurities, and crush the rare earth intermediate alloy into particles with a diameter ≤2cm. Then, place the three raw materials separately into an ultrasonic cleaner and clean them with a 5% dilute sulfuric acid solution for 10-15 minutes to remove the surface oxide layer, oil, and dust; then rinse them three times with deionized water, and finally place them in a 120℃ vacuum drying oven to dry for 2 hours to prevent the formation of bubbles during smelting.

[0077] 2. Segmented smelting and composition adjustment

[0078] Phase 1: Copper-based smelting: A medium-frequency induction furnace (power 50-100kW, frequency 1500-2500Hz) is used. The pre-treated copper segments are first placed into a crucible (a graphite crucible, preheated to 800℃ for 2 hours to remove moisture before use). An inert gas (argon, 99.99% purity) is introduced for protection to prevent copper oxidation. The temperature is raised to 1083℃ (copper melting point) and held for 30 minutes to completely melt the copper, forming molten copper. During this process, the copper is slowly stirred with a graphite stirring rod (10-15 r / min) to ensure uniform temperature. The surface of the molten copper is observed; if oxide slag appears, it is gently removed with a graphite spoon.

[0079] Phase Two: Silver Addition and Dissolution: After the copper liquid stabilizes, slowly add the pretreated silver particles in 3-5 batches (5 minutes apart) to the copper liquid to prevent the silver particles from sinking rapidly to the bottom of the crucible and causing localized overheating. After adding the silver, continue to maintain the temperature for 20 minutes, controlling it at 1100-1150℃. Utilizing the good miscibility of silver and copper, ensure the silver is completely dissolved in the copper liquid. At this point, take a sample and detect the silver content in the alloy using a direct-reading spectrometer. If the preset value is not reached, add more silver particles at a ratio of "0.1 kg of silver particles per 100 kg of copper liquid to increase the silver content by 0.1%" until the silver content meets the requirements.

[0080] Phase 3: Rare Earth Addition and Refining: Slowly add the rare earth master alloy to the copper-silver alloy melt, controlling the temperature at 1150-1200℃ (the melting point of the rare earth master alloy is approximately 900-1000℃), and hold for 25-30 minutes. Rare earth elements readily react with impurities such as oxygen and sulfur in the copper melt to form high-melting-point compounds (such as La2O3 and CeS). A special refining agent (such as a mixture of borax and sodium carbonate, added at 0.5%-1% of the alloy melt mass) needs to be sprinkled onto the surface of the copper melt to promote the polymerization of impurity compounds into slag. After standing for 15 minutes, remove the surface slag with a graphite spoon, and take another sample to test the rare earth content, ensuring it is within the range of 0.1%-0.3%.

[0081] 3. Ingot forming

[0082] Mold pretreatment: Select a steel mold (the specifications are determined according to the subsequent wire drawing requirements, usually a cylindrical mold with a diameter of 50-80mm and a length of 300-500mm). Apply graphite lubricant (graphite powder and alcohol are mixed at a ratio of 1:3) to the inner wall of the mold, and then put it into an oven at 200-250℃ for 1 hour to prevent the alloy liquid from sticking to the mold when it cools.

[0083] Casting and Cooling: The refined copper-silver-rare earth alloy molten material is slowly poured into a preheated mold at a temperature of 1150-1200℃ and a flow rate of 5-8 kg / min to avoid splashing or creating pores due to excessive flow rate. After casting, the mold is placed in a slow cooling pit (lined with insulation cotton, maintaining the temperature at 300-400℃) and cooled in the furnace for 24 hours to ensure uniform internal structure and reduce internal stress. After cooling, the mold is demolded to obtain a copper-silver-rare earth alloy ingot. The ingot surface should be free of defects such as cracks, pores, and inclusions; otherwise, it needs to be remelted.

[0084] II. Copper-Silver-Rare Earth Alloy Wire Drawing Process

[0085] The wire drawing process uses "multi-pass diameter reduction and gradual deformation" to process alloy ingots into conductor wires that meet cable specifications. Simultaneously, annealing is used to eliminate work hardening. The specific steps are as follows:

[0086] 1. Ingot Pretreatment

[0087] Ingot straightening and cutting: A hydraulic straightening machine (pressure 5-10MPa) is used to straighten the alloy ingot, ensuring that the straightness error of the ingot is ≤0.5mm / m. Then, a saw is used to cut the ingot into blanks with a length of 1-1.5m. The cut surface must be flat and the perpendicularity error ≤1° to avoid uneven force during subsequent wire drawing, which may cause wire breakage.

[0088] Surface polishing: The cut billet is placed in a centerless grinder (grit size 80-120 mesh) to polish the surface, remove oxide scale, burrs and defects from the surface of the ingot, so that the surface roughness Ra of the billet is Ra≤1.6μm, reduce the wear of the die during the wire drawing process, and avoid surface defects from affecting the quality of the wire.

[0089] 2. Multi-pass wire drawing forming

[0090] Wire drawing die selection: Based on the final conductor specifications (e.g., diameter 0.5-2mm), design the number of wire drawing passes (usually 8-12 passes). Use a diamond wire drawing die (hardness HV≥8000) for each pass. The die bore diameter is determined according to the principle of "diameter reduction rate of 15%-20% per pass" (e.g., billet diameter 50mm → first pass 42mm → second pass 35mm → ... → final pass 0.8mm). Before use, the die must be cleaned for 10 minutes with an ultrasonic cleaner (cleaning solution is neutral detergent, temperature 40-50℃) to remove impurities from the die bore.

[0091] Wire drawing process control: First drawing: One end of the pretreated billet is upset by a cold heading machine (the tip diameter is 1-2mm smaller than the first die hole diameter), and then introduced into a continuous wire drawing machine (traction speed 5-10m / min). During the wire drawing process, an emulsion (composition: 90% water, 5% mineral oil, 3% extreme pressure agent, 2% rust inhibitor) is used for cooling and lubrication. The emulsion temperature is controlled at 30-40℃ and the pressure is 0.3-0.5MPa to ensure sufficient lubrication between the wire and the die, while also removing the heat generated during wire drawing.

[0092] Intermediate drawing passes: After the first drawing pass is completed, the wire enters the subsequent drawing passes. The drawing speed of each pass gradually increases as the wire diameter decreases (the final pass speed can reach 50-80 m / min), while the emulsion parameters remain unchanged. After every 3 drawing passes, the surface of the wire needs to be inspected. If surface scratches, cracks, or other defects are found, the die needs to be replaced or the drawing parameters adjusted.

[0093] Final wire drawing: The die diameter for the final wire drawing stage must precisely match the conductor design specifications (e.g., diameter 0.8mm ± 0.01mm). During wire drawing, the traction tension must be kept stable (tension fluctuation range ≤ ±5%) to avoid diameter deviation due to uneven tension. After wire drawing, the wire diameter is monitored in real time using an online diameter gauge (accuracy 0.001mm) to ensure it meets the requirements.

[0094] 3. Intermediate annealing treatment

[0095] Purpose of annealing: After each 4-5 drawing passes, the wire hardens due to work hardening, resulting in increased hardness and decreased plasticity. Annealing is necessary to restore the wire's plasticity and prepare it for subsequent drawing.

[0096] Annealing process parameters: A continuous bright annealing furnace is used (protective atmosphere: hydrogen, purity 99.99%). The annealing temperature is controlled at 450-550℃ (adjusted according to the drawing passes, with slightly higher temperatures in the early passes and slightly lower temperatures in the later passes). The holding time is 10-15 minutes, the heating rate is 5-8℃ / min, and the cooling rate is 3-5℃ / min. After annealing, the Vickers hardness of the wire should be controlled between HV80-100, and the elongation should be ≥25% to ensure that the wire is not easily broken during subsequent drawing.

[0097] 4. Finished product winding

[0098] Preparation for winding up the wire: Select a spool (made of plastic or steel, with specifications determined according to the length of the wire, usually capable of holding 1000-2000m of wire). Before winding up the wire, clean and dry the spool to ensure that there is no oil or impurities on the surface.

[0099] Take-up control: The wire after the final drawing pass is introduced into the take-up machine. The take-up speed is synchronized with the drawing speed (50-80m / min), and the take-up tension is controlled at 5-10N (adjusted according to the wire diameter; the smaller the diameter, the lower the tension). This ensures that the wire is evenly wound on the spool without overlapping or looseness. After take-up, the wire is labeled with specifications, batch number, production date, and other information, and stored in a dry, ventilated warehouse for later use.

[0100] III. Conductor Electroless Nickel-Phosphorus Alloy Plating Process

[0101] By chemically plating to form a uniform and dense nickel-phosphorus alloy layer (7μm ± 0.5μm thick) on the conductor surface, the conductor's resistance to salt spray and chemical corrosion is significantly improved. The specific steps are as follows:

[0102] 1. Conductor pretreatment

[0103] Degreasing and oil removal: Place the drawn conductor wire into a degreasing tank (the degreasing agent is an alkaline degreasing agent, with the following components: sodium hydroxide 50g / L, sodium carbonate 30g / L, sodium phosphate 20g / L, surfactant 5g / L; solution temperature 50-60℃), and soak for 15-20 minutes, during which time compressed air is used for stirring (pressure 0.2-0.3MPa) to ensure that the oil on the conductor surface is completely removed. After degreasing, rinse the wire in a deionized water tank 3 times, 5 minutes each time, until the surface pH value is neutral (pH=6-7).

[0104] Pickling for rust removal: Immerse the degreased wire in a pickling tank (the pickling solution is a 10% dilute sulfuric acid solution, temperature 25-30℃) for 5-8 minutes to remove the oxide film on the conductor surface. During the pickling process, the wire needs to be turned regularly to ensure uniform pickling and avoid excessive local corrosion. After pickling, immediately rinse three times with deionized water for 5 minutes each time, then neutralize in a 5% sodium carbonate solution for 2 minutes, rinse again with deionized water until neutral, and finally dry in a 120℃ oven for 10 minutes to prevent residual moisture on the surface from affecting the chemical plating effect.

[0105] 2. Preparation of electroless nickel-phosphorus alloy plating solution

[0106] According to the composition and content of the plating solution shown in Table 1, the plating solution is prepared using the method of "stepwise dissolution and gradual mixing". The specific steps are as follows:

[0107] Preparation of base solution: Add 50L of deionized water to a 100L mixing tank and heat to 40-50℃. Add nickel sulfate, sodium hypophosphite, sodium acetate, and sodium citrate in sequence. After each reagent is added, stir with a stirrer (50-80r / min) for 15 minutes to ensure that the reagent is completely dissolved and no precipitate is formed.

[0108] Adding complexing agents and stabilizers: Slowly add lactic acid to the base solution and stir for 10 minutes; then add stabilizers (such as thiourea, concentration 1 mg / L) and brighteners (such as saccharin, concentration 5 mg / L), and continue stirring for 20 minutes to make the plating solution composition uniform.

[0109] pH adjustment and volume adjustment: Adjust the pH of the plating solution to 4.5-5.0 using a 10% sodium hydroxide solution or a 10% sulfuric acid solution (using a precision pH meter with an accuracy of 0.01). Then add deionized water to bring the volume to 100L. Stir for 30 minutes, let stand for 1 hour, and filter to remove minute impurities from the plating solution to obtain a clear electroless nickel-phosphorus alloy plating solution.

[0110] 3. Chemical plating process control

[0111] Preheating and parameter setting of the plating tank: Pour the prepared plating solution into the chemical plating tank (made of polypropylene to avoid metal ion contamination of the plating solution). Use water bath heating to control the temperature of the plating solution at 85-90℃ (temperature fluctuation range ≤ ±1℃). At the same time, introduce compressed air (pressure 0.1-0.2MPa) to stir the plating solution to ensure uniform temperature and consistent composition.

[0112] Conductor immersion and plating thickness control: The pretreated conductor wire is introduced into the plating tank via a wire feeding rack. A continuous plating process is used, controlling the residence time of the wire in the plating solution to 25-30 minutes (adjusted according to the required plating thickness; approximately 1.2-1.5 μm plating is formed every 5 minutes, and approximately 7 μm plating is formed after 30 minutes). Sodium hypophosphite in the plating solution decomposes at 85-90℃ to produce phosphorus, which, along with nickel ions, is deposited on the conductor surface to form a nickel-phosphorus alloy layer (phosphorus content 8%-12%, amorphous structure, excellent corrosion resistance).

[0113] Plating solution maintenance: During the electroless plating process, sample the nickel ion concentration in the plating solution every hour (using EDTA titration). If the nickel ion concentration is below 20 g / L, add nickel sulfate at a ratio of 500 g nickel sulfate per 100 L of plating solution to increase the nickel ion concentration by 1 g / L. Simultaneously, add sodium hypophosphite (0.8 times the amount of nickel sulfate) to maintain the balance between the reducing agent and nickel ions in the plating solution. Replace the plating solution filter element (1 μm pore size) every 4 hours to remove deposits and ensure a uniform coating.

[0114] 4. Post-processing and quality inspection

[0115] Cleaning and drying: After the conductor wire is pulled out of the plating tank, it is immediately placed in a deionized water tank for 3 rinses, 5 minutes each time, to remove the residual plating solution on the surface; then it is placed in an 80-100℃ hot air dryer for 15 minutes to ensure that there is no moisture residue on the plating surface.

[0116] Coating thickness inspection: Using an X-ray fluorescence thickness gauge (accuracy 0.1μm), the thickness of the nickel-phosphorus alloy layer is inspected at different locations on the conductor wire (at least 5 points, 100m apart) to ensure that the thickness is within the range of 7μm±0.5μm. If the thickness is insufficient, the plating solution temperature needs to be adjusted or the dwell time needs to be extended; if the thickness exceeds the standard, the plating solution temperature needs to be reduced or the dwell time needs to be shortened.

[0117] Adhesion and corrosion resistance testing: Adhesion test: The cross-cut test is used (cross-cut knife spacing 1mm, cut depth to conductor substrate). After cutting the surface of the coating, 3M tape is used to stick it and then quickly peeled off. Observe whether the coating is peeling off. If the peeling area is ≤5%, the adhesion is qualified.

[0118] Corrosion resistance test: Cut a 100mm long nickel-plated conductor and immerse it in a 5% sodium chloride solution (temperature 35℃) for a salt spray test (according to GB / T10125 standard). After spraying continuously for 24 hours, take out the conductor and observe whether there are corrosion spots on the surface. If there is no obvious corrosion and the plating layer is well bonded to the substrate, the corrosion resistance is qualified.

[0119] In this embodiment, the step of mixing the conductor components and preparing them into a wire includes:

[0120] Step 1: Raw material cleaning

[0121] The copper rod is cut into small segments of 5-10cm in length. The silver particles are sieved to remove impurities. The rare earth intermediate alloy is crushed into particles with a diameter of ≤2cm. Then, the copper rod, silver particles and rare earth intermediate alloy are placed in an ultrasonic cleaner and cleaned with 5% dilute sulfuric acid solution for 10-15 minutes to remove the surface oxide layer, oil and dust. Then, they are rinsed three times with deionized water and finally placed in a vacuum drying oven at 120℃ for 2 hours.

[0122] Segmented melting and composition adjustment

[0123] Phase 1: Copper rod smelting: A medium-frequency induction melting furnace is used. The pre-treated copper segments are first put into the crucible, which is a graphite crucible. Before use, it is preheated at 800℃ for 2 hours to remove moisture. Inert gas is introduced for protection to prevent copper oxidation. The temperature is raised to the melting point of copper, 1083℃, and held for 30 minutes to completely melt the copper and form molten copper. During this period, the copper is slowly stirred with a graphite stirring rod. At the same time, the surface of the molten copper is observed. If oxide slag appears, it is gently removed with a graphite spoon.

[0124] Phase Two: Silver Addition and Dissolution

[0125] After the copper liquid stabilizes, the pretreated silver particles are slowly added to the copper liquid in 3-5 batches, with an interval of 5 minutes between each batch. The liquid is then kept warm for another 20 minutes, with the temperature controlled at 1100-1150℃. Taking advantage of the good miscibility between silver and copper, the silver is completely dissolved in the copper liquid. At this point, a sample is taken, and the silver content in the alloy is detected by a direct-reading spectrometer. If the preset value is not reached, silver particles are added until the silver content meets the requirements, thus obtaining a copper-silver alloy liquid.

[0126] The third stage: rare earth addition and refining: the rare earth intermediate alloy is slowly added to the copper-silver alloy liquid, the temperature is controlled at 1150-1200℃, and the temperature is held for 25-30 minutes. A mixture of borax and sodium carbonate is added at a rate of 0.5%-1% of the alloy liquid mass. After standing for 15 minutes, the surface slag is removed with a graphite spoon, and the rare earth content is tested again to ensure that it is within the range of 0.1%-0.3%.

[0127] Step 2: Ingot Forming

[0128] Mold pretreatment: Select a steel mold, apply graphite lubricant (a mixture of graphite powder and alcohol in a 1:3 ratio) to the inner wall of the mold, and then preheat it in an oven at 200-250℃ for 1 hour to prevent the alloy liquid from sticking to the mold when it cools.

[0129] Casting and Cooling: The refined copper-silver-rare earth alloy liquid is slowly poured into the preheated mold at a flow rate of 5-8 kg / min at a temperature of 1150-1200℃. After casting, the mold is placed in a slow cooling pit, which is lined with heat insulation cotton and the temperature is maintained at 300-400℃. The mold is cooled with the furnace for 24 hours. After cooling, the mold is demolded to obtain a copper-silver-rare earth alloy ingot. The surface of the ingot should be free of defects such as cracks, pores, and inclusions. Otherwise, it needs to be remelted.

[0130] Step 3: Ingot Pretreatment

[0131] Ingot straightening and cutting: A hydraulic straightening machine is used to straighten the alloy ingots, ensuring that the straightness error of the ingots is ≤0.5mm / m. Then, a saw is used to cut the ingots into billets with a length of 1-1.5m. The cut surfaces must be flat, and the perpendicularity error must be ≤1°.

[0132] The cut billet is placed in a centerless grinder for surface polishing to remove oxide scale, burrs, and defects from the ingot surface, achieving a surface roughness Ra ≤ 1.6μm. Multi-pass wire drawing is then performed, with the number of drawing passes designed according to the final conductor specifications. A diamond drawing die is used for each pass.

[0133] First wire drawing: One end of the pretreated billet is upset using a cold heading machine, making the tip diameter 1-2 mm smaller than the diameter of the first die hole. It is then introduced into a continuous wire drawing machine. During the wire drawing process, an emulsion is used, consisting of the following weight percentages: water 90%, mineral oil 5%, extreme pressure agent 3%, and rust inhibitor 2%. This emulsion is used for cooling and lubrication. The emulsion temperature is controlled at 30-40℃, and the pressure at 0.3-0.5 MPa.

[0134] Intermediate drawing passes: After the first drawing pass is completed, the wire enters the subsequent drawing passes. The traction speed of each pass gradually increases as the wire diameter decreases, while the emulsion parameters remain constant. After every 3 drawing passes, the surface of the wire must be inspected. If surface scratches, cracks, or other defects are found, the die must be replaced or the drawing parameters adjusted.

[0135] Final wire drawing: The diameter of the final wire drawing die must be precisely matched to the conductor design specifications. During wire drawing, the traction tension must be controlled to be stable. The wire diameter is detected in real time using an online diameter measuring instrument to ensure that it meets the requirements.

[0136] In this embodiment, the step of chemically plating a nickel-phosphorus alloy layer onto the surface of the conductor includes: a conductor chemical plating nickel-phosphorus alloy treatment process.

[0137] Step 1: Conductor pretreatment

[0138] Degreasing and oil removal: Place the drawn conductor wire into a degreasing tank containing an alkaline degreasing agent. The alkaline degreasing agent consists of 50g / L sodium hydroxide, 30g / L sodium carbonate, 20g / L sodium phosphate, and 5g / L surfactant. The solution temperature is 50-60℃. Soak for 15-20 minutes. After degreasing, rinse the wire in a deionized water tank three times for 5 minutes each time until the surface pH value is neutral.

[0139] Pickling and rust removal: Place the degreased wire into the pickling tank. The pickling solution is a 10% dilute sulfuric acid solution. The temperature is 25-30℃. Soak for 5-8 minutes to remove the oxide film on the conductor surface. During the pickling process, the wire needs to be turned over regularly. After pickling, immediately rinse with deionized water 3 times, 5 minutes each time. Then, neutralize in a 5% sodium carbonate solution for 2 minutes. Rinse with deionized water until neutral. Finally, dry in a 120℃ oven for 10 minutes.

[0140] Step 2: Preparation of electroless nickel-phosphorus alloy plating solution:

[0141] Add 50L of deionized water to a 100L mixing tank and heat to 40-50℃. Add nickel sulfate, sodium hypophosphite, sodium acetate, and sodium citrate in sequence. After each reagent is added, stir for 15 minutes to ensure that the reagent is completely dissolved and no precipitate is formed. Slowly add lactic acid to the base solution and stir for 10 minutes. Then add stabilizer and brightener and continue stirring for 20 minutes to make the composition of the plating solution uniform. Adjust the pH of the plating solution to 4.5-5.0 with 10% sodium hydroxide solution or 10% sulfuric acid solution. Then add deionized water to make up to 100L. Stir for 30 minutes and let stand for 1 hour. Filter to remove tiny impurities from the plating solution to obtain a clear electroless nickel-phosphorus alloy plating solution.

[0142] Step 3: Chemical Plating Process Control

[0143] The prepared electroless nickel-phosphorus alloy plating solution is injected into the electroless plating tank. The temperature of the plating solution is controlled at 85-90℃ using a water bath heating method. At the same time, compressed air is introduced to stir the plating solution to ensure uniform temperature and consistent composition. The pretreated conductor wire is introduced into the plating tank through a wire feeding rack. The continuous plating method is adopted, and the residence time of the wire in the plating solution is controlled to be 25-30 minutes. The sodium hypophosphite in the plating solution decomposes at 85-90℃ to produce phosphorus, which is deposited on the conductor surface together with nickel ions to form a nickel-phosphorus alloy layer.

[0144] In this embodiment, the thickness of the nickel-phosphorus alloy layer is 7μm±0.5μm.

[0145] In this embodiment, the conductor is covered from the inside out with an insulating layer 2, a shielding layer 3, a rodent-resistant layer 4, a salt spray and chemical corrosion resistant layer 5, and a mechanical protection and anti-aging layer 6.

[0146] The cable of the present invention has an insulation layer 2, a shielding layer 3, a rodent-resistant layer 4, a salt spray and chemical corrosion resistant layer 5, and a mechanical protection and anti-aging layer 6 as the center of the conductor 1.

[0147] In this embodiment, the insulating layer 2 is a composite insulating material of polyether ether ketone and nano boron nitride.

[0148] In this invention, the insulation layer 2 is formed around the outer layer of the conductor 1. Specifically, polyetheretherketone (PEEK) and nano-boron nitride are mixed in a 2:8 ratio, and 22g of ultraviolet absorber is added. The mixture is then thoroughly stirred in a high-speed mixer. The mixture is added to an extruder, and the insulation layer 2 is extruded through a precision die under specific conditions of 90-100℃ and 56MPa pressure. The thickness of the insulation layer 2 is controlled to be 1.2-1.4mm according to the 0.6 / 1kV voltage level. During the extrusion process, the temperature, pressure, and extrusion speed are precisely controlled to ensure the quality of the insulation layer 2.

[0149] In this embodiment, the shielding layer 3 includes an inner shielding layer and an outer shielding layer. The inner shielding layer is wrapped with amorphous alloy strip, and the outer shielding layer is a silver-plated copper wire braided mesh.

[0150] In this invention, the shielding layer 3 is formed around the insulating layer 2. Specifically, a high-permeability amorphous alloy strip is first wrapped around the insulating layer 2 with a certain overlap rate to form an inner shield. Then, silver-plated copper wire is woven around it to form an outer shield. Between the two shielding layers, a graphene-modified semi-conductive buffer material is uniformly coated, and the thickness of the semi-conductive buffer layer is controlled to be 0.3-0.4 mm.

[0151] In this embodiment, the anti-rat and ant layer 4 is made of a thermoplastic elastomer of peppermint oil and organosilicon flame retardant.

[0152] In this invention, an anti-rodent layer 4 is formed around the shielding layer 3. Specifically, thermoplastic elastomer (TPE) raw material containing natural plant extracts and organosilicon flame retardants is added to an extruder and extruded using a specially designed semi-extrusion die to form the anti-rodent layer 4 outside the shielding layer 3. The thickness of the anti-rodent layer 4 is controlled at 1.5-1.8 mm, ensuring a uniform distribution of micro-protrusion structures on its surface. (A semi-extrusion die is used, with temperatures of 110, 112, 118, 123, 135, 145, and 155 °C.)

[0153] In this embodiment, the salt spray resistant and chemical corrosion resistant layer 5 adopts a three-layer composite structure, with the inner layer being a polytetrafluoroethylene layer, the middle layer being an aramid fiber reinforced ethylene-tetrafluoroethylene copolymer layer, and the outer layer being a nano-silica modified fluorocarbon coating.

[0154] In this invention, a salt spray-resistant and chemical-resistant layer 5 is formed around a rodent-resistant layer 4. Specifically, a polytetrafluoroethylene (PTFE) layer is first extruded onto the rodent-resistant layer 4, with a thickness controlled at 2.2-2.4 mm. Then, aramid fibers are impregnated in ethylene-tetrafluoroethylene copolymer (ETFE) resin and wound around the PTFE layer in a left-hand winding manner to form an intermediate layer. The number of winding layers is determined according to actual needs. Finally, a nano-silica-modified fluorocarbon coating is sprayed onto the intermediate layer to form a fluorocarbon coating, with a coating thickness controlled at 2.1-2.4 mm. During the preparation of each layer, process parameters are strictly controlled to ensure the bonding strength between layers and the overall performance (i.e., thickness).

[0155] In this embodiment, the mechanical protection and anti-aging layer 6 is made of polyurethane and carbon fiber composite material.

[0156] In this invention, a mechanical protection and anti-aging layer 6 is formed around the salt spray resistance and chemical corrosion resistance layer 5. Specifically, polyurethane (PU) and carbon fiber are mixed at a ratio of 1.5:8.5, and antioxidants and light stabilizers are added, and the mixture is thoroughly and uniformly mixed in a mixing device. An extrusion process is used to form the mechanical protection and anti-aging layer 6 outside the salt spray resistance and chemical corrosion resistance layer 5, with the thickness controlled at 1.6-1.8 mm according to the cable specifications. During the molding process, temperature, pressure, and cooling rate are controlled to ensure material properties and dimensional accuracy.

[0157] Table 2 Forming of Mechanical Protection and Anti-aging Layer

[0158]

[0159] The extrusion pressure is generally controlled between 10-20 mmPa, and the pressure affects the extrusion speed and molding quality of the material.

[0160] The corrosion-resistant multifunctional special power cable prepared by the above process has undergone rigorous performance testing, and all its performance indicators have met or exceeded the relevant standard requirements, demonstrating good performance and reliability in actual harsh environment applications.

[0161] Performance testing

[0162] 1. Electrical performance

[0163] Conductor resistance: According to GB / T3956 standard, at 20℃, the resistance of copper-silver-rare earth alloy conductors is reduced by 8%-10% compared to ordinary copper conductors. For example, a conductor with a nominal cross-sectional area of ​​50mm²... 2 The conductor has a measured resistance of ≤0.0387Ω / km, which effectively reduces transmission loss and improves power transmission efficiency.

[0164] Insulation resistance: Cross-linked polyethylene insulation is used. At 20℃, the insulation resistance is ≥10000MΩ·km, which far exceeds the standard of conventional cables, ensuring good insulation performance and reducing the risk of leakage.

[0165] Withstand voltage test: The finished cable can withstand a 6.5kV / 5min power frequency withstand voltage test. There is no breakdown or flashover during the test, which meets the safety requirements of high voltage power transmission.

[0166] 2. Mechanical protection performance

[0167] Tensile strength: Tested by a tensile testing machine, the overall tensile strength of the cable is ≥5000N. The conductor, insulation layer and sheath are firmly bonded. During laying and use, it can effectively resist external tensile forces and avoid damage to the cable structure.

[0168] Bending performance: Under the condition that the bending radius is 8 times the outer diameter of the cable, after repeated bending 100 times, the cable insulation and sheath are free from cracks and damage, and the conductor is free from broken strands, ensuring the reliability of the cable in complex wiring scenarios.

[0169] Rodent and ant resistance: According to GB / T34016-2017 standard, rat biting test was conducted, and the protection rate P≥0.9. The surface of the sample sheath was free of tooth marks or only had slightly visible bite marks, and the bite depth was <1mm. Termite infestation test was conducted using the experimental group method. No termite infestation tooth marks were observed on the cable surface, indicating a significant rodent and ant resistance effect.

[0170] 3. Corrosion resistance

[0171] Salt spray corrosion test: According to GB / T29631-2013 standard, the cable is placed in a salt spray test chamber and sprayed continuously for 5000 hours. The nickel-phosphorus alloy layer on the conductor surface shows no obvious corrosion or peeling. The cable insulation resistance retention rate is ≥95%, which shows excellent resistance to salt spray corrosion and is suitable for coastal and high salt spray areas.

[0172] Acid and alkali corrosion test: The cable was immersed in 10% sulfuric acid and sodium hydroxide solutions respectively. After immersion at room temperature for 1000 hours, the sheath showed no deformation, discoloration or dissolution, the insulation performance was normal, and the conductor resistance change rate was ≤±1%, effectively resisting acid and alkali corrosion.

[0173] 4. Environmental adaptability

[0174] High and low temperature performance: According to GB / T2951 standard, after being placed at a high temperature of 120℃ for 168 hours, the cable insulation and sheath did not soften or flow; after being subjected to a cold bending test at a low temperature of -40℃, the cable insulation and sheath did not crack, and it can operate stably in extreme high and low temperature environments.

[0175] Weather resistance: Through artificial accelerated aging test (simulating environmental factors such as ultraviolet rays, rain, and temperature changes for 2000 hours), the surface of the cable sheath is free from cracks and powdering, and the color change ΔE≤3, maintaining good performance and adapting to long-term outdoor use environment.

[0176] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0177] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0178] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0179] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0180] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A rodent- and ant-proof, salt spray-resistant special power cable, characterized in that, Includes a conductor (1), said conductor (1) being manufactured in the following manner: The conductor (1) is composed of the following components by weight percentage: Copper content ≥ 99.5% Silver content 0.2%-0.5%, Rare earth element content: 0.1%-0.3%; Among them, the copper uses T2 oxygen-free copper rod with a purity of 99.95% or higher, the silver uses 99.99% high-purity silver particles, and the rare earth uses rare earth intermediate alloy. The rare earth content of the rare earth intermediate alloy is 20%-30%, and the rare earth intermediate alloy is a copper-lanthanum alloy or a copper-cerium alloy. The components of conductor (1) are mixed and prepared into a wire; The surface of the conductor (1) is chemically plated with a nickel-phosphorus alloy layer, the composition of which is shown in the table below: 。 2. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 1, characterized in that, The step of mixing the components of conductor (1) and preparing it into a wire includes: Step 1: Raw material cleaning The copper rod is cut into small segments of 5-10cm in length. The silver particles are sieved to remove impurities. The rare earth intermediate alloy is crushed into particles with a diameter of ≤2cm. Then, the copper rod, silver particles and rare earth intermediate alloy are placed in an ultrasonic cleaner and cleaned with 5% dilute sulfuric acid solution for 10-15 minutes to remove the surface oxide layer, oil and dust. Then, they are rinsed three times with deionized water and finally placed in a vacuum drying oven at 120℃ for 2 hours. Segmented melting and composition adjustment Phase 1: Copper rod smelting: A medium-frequency induction melting furnace is used. The pre-treated copper segments are first put into the crucible, which is a graphite crucible. Before use, it is preheated at 800℃ for 2 hours to remove moisture. Inert gas is introduced for protection to prevent copper oxidation. The temperature is raised to the melting point of copper, 1083℃, and held for 30 minutes to completely melt the copper and form molten copper. During this period, the copper is slowly stirred with a graphite stirring rod. At the same time, the surface of the molten copper is observed. If oxide slag appears, it is gently removed with a graphite spoon. Phase Two: Silver Addition and Dissolution After the copper liquid stabilizes, the pretreated silver particles are slowly added to the copper liquid in 3-5 batches, with an interval of 5 minutes between each batch. The liquid is then kept warm for another 20 minutes, with the temperature controlled at 1100-1150℃. Taking advantage of the good miscibility between silver and copper, the silver is completely dissolved in the copper liquid. At this point, a sample is taken, and the silver content in the alloy is detected by a direct-reading spectrometer. If the preset value is not reached, silver particles are added until the silver content meets the requirements, thus obtaining a copper-silver alloy liquid. The third stage: rare earth addition and refining: the rare earth intermediate alloy is slowly added to the copper-silver alloy liquid, the temperature is controlled at 1150-1200℃, and the temperature is held for 25-30 minutes. A mixture of borax and sodium carbonate is added at a rate of 0.5%-1% of the alloy liquid mass. After standing for 15 minutes, the surface slag is removed with a graphite spoon, and the rare earth content is tested again to ensure that it is within the range of 0.1%-0.3%. Step 2: Ingot Forming Mold pretreatment: Select a steel mold, apply graphite lubricant to the inner wall of the mold, and then preheat it in an oven at 200-250℃ for 1 hour to prevent the alloy liquid from sticking to the mold when it cools. Casting and Cooling: The refined copper-silver-rare earth alloy liquid is slowly poured into the preheated mold at a flow rate of 5-8 kg / min at a temperature of 1150-1200℃. After casting, the mold is placed in a slow cooling pit, which is lined with heat insulation cotton and the temperature is maintained at 300-400℃. The mold is cooled with the furnace for 24 hours. After cooling, the mold is demolded to obtain a copper-silver-rare earth alloy ingot. The surface of the ingot should be free of defects such as cracks, pores, and inclusions. Otherwise, it needs to be remelted. Step 3: Ingot Pretreatment Ingot straightening and cutting: A hydraulic straightening machine is used to straighten the alloy ingots, ensuring that the straightness error of the ingots is ≤0.5mm / m. Then, a saw is used to cut the ingots into billets with a length of 1-1.5m. The cut surfaces must be flat, and the perpendicularity error must be ≤1°. The cut billet is placed in a centerless grinder to polish the surface, removing oxide scale, burrs and defects from the ingot surface, so that the surface roughness Ra of the billet is ≤1.6μm. The billet is then drawn in multiple passes. The number of drawing passes is designed according to the final conductor (1) specifications, and a diamond drawing die is used for each pass. First wire drawing: One end of the pretreated billet is upset using a cold heading machine, making the tip diameter 1-2 mm smaller than the diameter of the first die hole. It is then introduced into a continuous wire drawing machine. During the wire drawing process, an emulsion is used, consisting of the following weight percentages: water 90%, mineral oil 5%, extreme pressure agent 3%, and rust inhibitor 2%. This emulsion is used for cooling and lubrication. The emulsion temperature is controlled at 30-40℃, and the pressure at 0.3-0.5 MPa. Intermediate drawing passes: After the first drawing pass is completed, the wire enters the subsequent drawing passes. The traction speed of each pass gradually increases as the wire diameter decreases, while the emulsion parameters remain constant. After every 3 drawing passes, the surface of the wire must be inspected. If surface scratches, cracks, or other defects are found, the die must be replaced or the drawing parameters adjusted. Final wire drawing: The diameter of the final wire drawing die must be precisely matched to the conductor (1) design specifications. During wire drawing, the traction tension is controlled to be stable. The wire diameter is detected in real time by an online diameter measuring instrument to ensure that it meets the requirements.

3. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 1, characterized in that, The step of chemically plating a nickel-phosphorus alloy layer on the surface of the conductor (1) includes: Step 1: Conductor (1) Pretreatment Degreasing and oil removal: The drawn conductor (1) wire is placed in a degreasing tank. The degreasing tank is equipped with an alkaline degreasing agent. The alkaline degreasing agent consists of 50g / L sodium hydroxide, 30g / L sodium carbonate, 20g / L sodium phosphate, and 5g / L surfactant. The solution temperature is 50-60℃. Soak for 15-20 minutes. After degreasing, the wire is placed in a deionized water tank and rinsed 3 times for 5 minutes each time until the surface pH value is neutral. Pickling and rust removal: Place the degreased wire into the pickling tank. The pickling solution is a 10% dilute sulfuric acid solution. The temperature is 25-30℃. Soak for 5-8 minutes to remove the oxide film on the surface of the conductor (1). During the pickling process, the wire needs to be turned over regularly. After pickling, rinse with deionized water 3 times for 5 minutes each time. Then put it into a 5% sodium carbonate solution to neutralize for 2 minutes. Rinse with deionized water until neutral. Finally, put it into a 120℃ oven to dry for 10 minutes. Step 2: Preparation of electroless nickel-phosphorus alloy plating solution Add 50L of deionized water to a 100L mixing tank and heat to 40-50℃. Add nickel sulfate, sodium hypophosphite, sodium acetate, and sodium citrate in sequence. After each reagent is added, stir for 15 minutes to ensure that the reagent is completely dissolved and no precipitate is formed. Slowly add lactic acid to the base solution and stir for 10 minutes. Then add stabilizer and brightener and continue stirring for 20 minutes to make the composition of the plating solution uniform. Adjust the pH of the plating solution to 4.5-5.0 with 10% sodium hydroxide solution or 10% sulfuric acid solution. Then add deionized water to make up to 100L. Stir for 30 minutes and let stand for 1 hour. Filter to remove tiny impurities from the plating solution to obtain a clear electroless nickel-phosphorus alloy plating solution. Step 3: Chemical Plating Process Control The prepared electroless nickel-phosphorus alloy plating solution is injected into the electroless plating tank. The temperature of the plating solution is controlled at 85-90℃ by water bath heating. At the same time, compressed air is introduced to stir the plating solution to ensure that the temperature of the plating solution is uniform and the composition is consistent. The pretreated conductor (1) wire is introduced into the plating tank through the wire feeding frame. The continuous plating method is adopted, and the residence time of the wire in the plating solution is controlled to be 25-30 minutes. The sodium hypophosphite in the plating solution decomposes at 85-90℃ to produce phosphorus, which is deposited together with nickel ions on the surface of the conductor (1) to form a nickel-phosphorus alloy layer.

4. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 1, characterized in that, The thickness of the nickel-phosphorus alloy layer is 7 μm ± 0.5 μm.

5. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 1, characterized in that, The conductor (1) is covered from the inside out with an insulating layer (2), a shielding layer (3), a rodent-resistant layer (4), a salt spray and chemical corrosion resistant layer (5), and a mechanical protection and anti-aging layer (6).

6. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 5, characterized in that, The insulating layer (2) is a composite insulating material of polyether ether ketone and nano boron nitride.

7. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 5, characterized in that, The shielding layer (3) includes an inner shielding layer and an outer shielding layer. The inner shielding layer is wrapped with amorphous alloy strip, and the outer shielding layer is a silver-plated copper wire braided mesh.

8. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 5, characterized in that, The anti-rodent layer (4) is made of a thermoplastic elastomer containing peppermint oil and silicone flame retardant.

9. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 5, characterized in that, The salt spray resistant and chemical corrosion resistant layer (5) adopts a three-layer composite structure, with the inner layer being a polytetrafluoroethylene layer, the middle layer being an aramid fiber reinforced ethylene-tetrafluoroethylene copolymer layer, and the outer layer being a nano-silica modified fluorocarbon coating.

10. The rodent-proof, ant-proof, and salt spray-resistant special power cable according to claim 5, characterized in that, The mechanical protection and anti-aging layer (6) is made of polyurethane and carbon fiber composite material.

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