Metallurgical bonding nickel-coated copper rod and wire manufacturing method

Abstract

The invention relates to the technical field of composite material preparation, in particular to a metallurgical bonding nickel-coated copper rod and wire manufacturing method. The method comprises the steps that a copper core is prepared, T1 oxygen-free copper powder and a borax adhesive are selected, stirred, extruded and polished, and copper core preparation is completed; shell preparation: selecting a nickel rod, cutting and then processing and forming to obtain a nickel shell and a nickel rear cover; and smelting treatment is conducted, specifically, a reinforcing agent is prepared, the interior of the nickel shell is cleaned, then the reinforcing agent is smeared, the copper core is arranged in the nickel shell, and the nickel shell is fed into a vacuum smelting furnace to be subjected to sealed smelting treatment. According to the nickel-coated copper bar, through mutual cooperation and mutual promotion of various components in the reinforcing agent, a compact metallurgical bonding layer is formed on a bonding interface of the nickel-coated copper bar, atoms of the bonding layer are arranged tightly and orderly, the bonding strength between copper and nickel is greatly enhanced, the two kinds of metal are not simply mechanically bonded any more, and the bonding strength of the nickel-coated copper bar is greatly improved. Instead, firm metallurgical bonding is formed through interdiffusion and chemical bonding among atoms.

Description

Technical Field

[0001] The present invention relates to the technical field of composite material preparation, and specifically to a method for manufacturing a nickel-coated copper rod and wire with metallurgical bonding. Background Art

[0002] With the rapid development of modern industry, the requirements for material properties are becoming increasingly stringent. In the fields of electronics and electricity, products are constantly developing towards miniaturization and high performance. This requires conductive materials to not only have good electrical conductivity but also certain strength, corrosion resistance, and stability. Although copper has excellent electrical conductivity, it has deficiencies in terms of strength and corrosion resistance; nickel has better corrosion resistance and stability, but its electrical conductivity is not as good as that of copper. Combining nickel and copper to make a nickel-coated copper rod can integrate the advantages of both and meet the diverse needs of industrial development for materials.

[0003] In the prior art, nickel-coated copper is processed by interference fit, either through cold extrusion or nickel plating on the copper core. The nickel-coated copper produced by interference fit does not form a metallurgical bond between the two metals. The two metals only have close contact. After being used for a period of time, oxidation will occur between the two metals, resulting in an increase in the contact resistance between the two metals. At the same time, when used at a temperature exceeding 100°C, the thermal expansion and contraction coefficients of the two metals are different. After repeated expansion and contraction, gaps will form between the two metals, leading to the separation of the two metals. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for manufacturing a nickel-coated copper rod and wire with metallurgical bonding. The method for manufacturing the nickel-coated copper rod and wire with metallurgical bonding prepared by the present invention not only has good bonding strength and high-temperature stability but also effectively improves the service performance of the method for manufacturing the nickel-coated copper rod and wire with metallurgical bonding.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A method for manufacturing a nickel-coated copper rod and wire with metallurgical bonding, comprising the following steps:

[0006] Step 1: Copper core preparation, select T1 oxygen-free copper powder and borax binder, stir, extrude, and polish to complete the copper core preparation;

[0007] Step 2: Outer shell preparation, select a nickel rod, cut it, and process it into a shape to obtain a nickel outer shell and a nickel rear cover;

[0008] Step 3: Melting treatment, prepare a reinforcing agent, clean the inside of the nickel outer shell, apply the reinforcing agent, then put the copper core into the inside of the nickel outer shell, and send it into a vacuum melting furnace for sealed melting treatment;

[0009] Step 4: Welding treatment, perform flaw detection on the nickel outer shell after melting treatment, and vacuum-weld the flaw-detected nickel outer shell and the nickel rear cover through a vacuum welding box;

[0010] Step 5: Extrusion treatment. The welded nickel shell is loaded into a high-temperature resistance furnace for heating and then extruded through an extruder to obtain a copper-clad nickel rod. After cooling, the head and tail of the copper-clad nickel rod are cut, and then the copper-clad nickel rod is drawn to the required size through a cold drawing process to complete the preparation.

[0011] Furthermore, the steps for preparing the copper core are as follows: T1 oxygen-free copper powder and borax binder are stirred to obtain a mixed powder. The mass ratio of the T1 oxygen-free copper powder to the borax binder is 20:3. The mixed powder is added to a forming die of a hydraulic press for extrusion molding. After taking out, it is polished with 800-mesh sandpaper to complete the preparation of the copper core.

[0012] Furthermore, the preparation of the shell includes the following steps. The nickel shell is selected as a nickel rod with a diameter of 125 mm, which is cut and then processed into shape, with a length of 290 mm. One end of the nickel shell is processed into a circular arc head with an R87.5, and the circular arc chamfer at the tangent of the circular arc and the processed outer diameter surface is R32.5. At the other end of the nickel shell, a hole with a diameter of 75 mm is processed at one end of the cross-section. The shape of the front end of the hole is the same as the outer diameter, and a 20×25° chamfer is processed on the outer diameter at the drilling end. The nickel rear cover is processed after being cut from a 125-mm nickel rod, with a cutting length of 30 mm, the diameter is processed to 120 mm, and the length is processed to 25 mm, and one end is chamfered at 20×25°.

[0013] Furthermore, the steps of the melting treatment are as follows: The inner hole of the nickel shell is wiped 3 - 5 times with industrial alcohol, and a reinforcing agent is coated onto the inner hole of the nickel shell through a spraying device. The coating thickness is 80 - 100 microns. After the copper core is loaded into the nickel shell, it is sent into a vacuum melting furnace, and argon gas is continuously injected into the vacuum melting furnace so that the argon gas in the furnace accounts for 99.8% of the furnace space. The purity of the argon gas is greater than 99.9%. The vacuum melting furnace is heated to 1280°C at a rate of 5 - 10°C / min and maintained for 3 h, and then cooled to room temperature. During the cooling process, when the temperature is greater than 80°C, continuous filling of argon gas is maintained until the temperature of the vacuum melting furnace is lower than 60°C, and then the filling of argon gas is stopped, and the nickel shell is taken out to complete the melting treatment.

[0014] Furthermore, the preparation method of the reinforcing agent is as follows: Foundry waste sand, aluminum ash, and borax are selected for pretreatment. After the foundry waste sand is crushed and screened, it is soaked in a 10% dilute hydrochloric acid solution for 30 - 40 min, then washed with deionized water until neutral, and dried with a dryer for standby. The aluminum ash is placed in a muffle furnace and heated to 800°C at a rate of 5 - 10°C / min for forging for 2 h. After taking out and cooling, the forged aluminum ash is ball-milled by a planetary ball mill at a speed of 250 - 350 r / min for 4 h and sieved through a 200-mesh sieve. The medium is zirconia balls, and the mass ratio of zirconia balls to aluminum ash is 4:1. The industrial-grade borax is dehydrated at 200°C and sieved through a 200-mesh sieve to complete the pretreatment of the foundry waste sand, aluminum ash, and borax.

[0015] Further, the pre-treated foundry waste sand, aluminum ash and borax are added to a V-type mixer and stirred at 20 - 40 r / min for 15 min to obtain a mixture. The mass ratio of the foundry waste sand, aluminum ash and borax is 6:3:1. The mixture is placed in a ball mill and anhydrous ethanol is added. The anhydrous ethanol accounts for 15% of the mass of the mixture and is stirred at 200 - 300 r / min for 6 h to obtain a slurry. The slurry is placed in a vacuum drying oven for drying. After drying, it is taken out and placed in a small crusher for crushing, and then sieved through a 200-mesh sieve to obtain a composite powder. The composite powder and PVA solution are stirred by a magnetic stirrer. During the stirring process, the composite powder is added continuously and stirred at 500 - 600 r / min for 30 - 40 min to complete the preparation of the reinforcing agent.

[0016] Further, the mass ratio of the composite powder to the PVA solution is 1:1, the concentration of the PVA solution is 5%, the temperature of the vacuum drying oven is set at 60°C and the vacuum degree is -0.1 MPa during the preparation of the reinforcing agent.

[0017] Further, the welding treatment steps are as follows: after the nickel outer shell after melting treatment is coarsely ground with a silicon carbide grinding wheel and finely polished with 800-mesh sandpaper, after the polishing is completed, UT flaw detection is carried out to remove abnormal products. After the nickel rear cover is cleaned, the nickel rear cover is placed on the end face of the qualified nickel outer shell and placed inside a vacuum welding box. The nickel outer shell and the nickel rear cover are welded by argon arc welding using the same welding wire as the nickel rear cover. After cooling, it is taken out and the weld bead is polished to be consistent with the outer diameter of the nickel outer shell to complete the welding treatment of the nickel outer shell.

[0018] Further, the steps of the extrusion treatment are as follows: the nickel outer shell after welding treatment is placed in a high-temperature resistance furnace and heated to 920°C at a rate of 5 - 10°C / min and then held for 2 h. It is taken out and placed in a 1500T extruder and extruded from the die to obtain a nickel-clad copper bar. The diameter of the die orifice is 28 mm. After the nickel-clad copper bar is cooled, the head and tail of the nickel-clad copper bar are cut, and the nickel-clad copper bar is drawn to the required size by a cold drawing process to complete the extrusion treatment.

[0019] Further, the reduction ratio of the diameter in each cold drawing process of the cold drawing process is less than 6.3%, the drawing speed is 2 - 5 m / min, and high-temperature annealing is carried out in an annealing furnace every 2 - 4 times of drawing. The annealing temperature is 680 - 720°C and lasts for 2 h.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. In the present invention, through the addition of an enhancer, at high temperature, borax will come into full contact with and react with the silicate in the foundry waste sand to form a low-melting glass phase, significantly improving the wettability of the molten copper liquid to the nickel wall. At the same time, the surface tension between the molten copper liquid and the nickel wall is reduced, enabling the copper liquid to adhere more uniformly and tightly to the inner wall of the nickel shell. Meanwhile, metallic aluminum captures the oxygen in the interfacial oxide, oxidizes itself, and the interfacial oxide is reduced to a pure metallic state, ensuring the cleanliness of the bonding surface and eliminating the key obstacles affecting metallurgical bonding. Through mutual cooperation and promotion, a dense metallurgical bonding layer is formed at the bonding interface of the nickel-coated copper rod. The atomic arrangement of this bonding layer is closely and orderly, greatly enhancing the bonding strength between copper and nickel, making the two metals no longer simply mechanically bonded, but forming a firm metallurgical bond through the mutual diffusion and chemical bonding between atoms.

[0022] 2. In the present invention, iron oxide in the foundry waste sand will interact with the boron oxide decomposed from borax at high temperature to form complex salt substances. These salt substances adhere tightly to the surface of the nickel-coated copper rod and wire, constituting a part of the protective film, which can effectively block the erosion of oxygen and moisture and enhance the corrosion resistance of the product. Meanwhile, borax will form boron trioxide at high temperature and react and accumulate with metallic aluminum and aluminum oxide in the aluminum ash, forming a transition layer at the bonding interface between copper and nickel. The composition and structure of the transition layer are between those of copper and nickel, which can relieve the thermal stress generated by the different thermal expansion coefficients of the two metals and improve the stability of the nickel-coated copper rod and wire in different temperature environments.

[0023] 3. In the present invention, by using foundry waste sand and aluminum ash as raw materials for the enhancer, the resource utilization of industrial waste is realized, and the raw material cost is reduced. Detailed implementation mode

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0025] It should be noted that the raw materials used in the following embodiments are all commercially available raw materials.

[0026] Embodiment 1:

[0027] A method for manufacturing a nickel-coated copper rod and wire with metallurgical bonding includes the following steps:

[0028] Step 1: Preparation of the copper core. Select T1 oxygen-free copper powder and borax binder, stir, extrude and polish to complete the preparation of the copper core.

[0029] Step 2: Shell preparation. Select a nickel rod, cut it, and process it into a nickel shell and a nickel back cover.

[0030] Step 3: Melting treatment. Prepare the reinforcing agent, clean the inside of the nickel shell, apply the reinforcing agent, then place the copper core inside the nickel shell, and send it into a vacuum melting furnace for sealed melting treatment.

[0031] Step 4: Welding treatment. Conduct flaw detection on the nickel shell after melting treatment, and vacuum weld the nickel shell after flaw detection and the nickel back cover through a vacuum welding box.

[0032] Step 5: Extrusion treatment. Place the welded nickel shell into a high-temperature resistance furnace for heating, then extrude it through an extruder to obtain a nickel-coated copper rod. After cooling, cut the head and tail of the nickel-coated copper rod, and then draw the nickel-coated copper rod to the required size through a cold drawing process to complete the preparation.

[0033] The steps for preparing the copper core are as follows: Stir T1 oxygen-free copper powder and borax binder to obtain a mixed powder. The mass ratio of T1 oxygen-free copper powder to borax binder is 20:3. Add the mixed powder into the forming die of a hydraulic press for extrusion molding. After taking it out, polish it with 800-mesh sandpaper to complete the preparation of the copper core.

[0034] The shell preparation includes the following steps. The nickel shell is selected from a 125-mm-diameter nickel rod, cut, and processed. Its length is 290 mm. One end of the nickel shell is processed into an arc head with a radius of R87.5, and the arc chamfer at the tangent of the arc and the processed outer diameter surface is R32.5. At the other end of the nickel shell, a 75-mm-diameter hole is processed at one end of the cross-section. The shape of the front end of the hole is the same as the outer diameter. A 20×25° chamfer is processed on the outer diameter at the drilling end. The nickel back cover is selected from a 125-mm nickel rod, cut, and processed. The cutting length is 30 mm, the diameter is processed to 120 mm, and the length is processed to 25 mm. One end is chamfered at 20×25°.

[0035] The steps for melting treatment are as follows: Wipe the inner hole of the nickel shell 3 times with industrial alcohol, and coat the inner hole of the nickel shell with the reinforcing agent through a spraying device. The coating thickness is 80 microns. After placing the copper core inside the nickel shell, send it into the vacuum melting furnace, continuously inject argon into the vacuum melting furnace until the argon in the furnace accounts for 99.8% of the furnace space, and the purity of argon is greater than 99.9%. The vacuum melting furnace is heated to 1250°C at a rate of 5°C / min and maintained for 3 h, and then cooled to room temperature. During the cooling process, when the temperature is greater than 80°C, keep the argon continuously filled until the temperature of the vacuum melting furnace is lower than 60°C, then stop filling argon and take it out to complete the melting treatment of the nickel shell.

[0036] The preparation method of the reinforcing agent is as follows: Select foundry waste sand, aluminum ash and borax for pretreatment. After crushing and screening the foundry waste sand, soak it in a 10% dilute hydrochloric acid solution for 30 minutes. Then, wash it with deionized water until neutral and dry it with a dryer for standby. Place the aluminum ash in a muffle furnace and forge it at a heating rate of 5 °C / min to 800 °C for 2 hours. After taking it out and cooling, ball-mill the forged aluminum ash with a planetary ball mill at a speed of 250 r / min for 4 hours and sieve it through a 200-mesh sieve. The medium is zirconia balls, and the mass ratio of zirconia balls to aluminum ash is 4:1. Dehydrate industrial-grade borax at 200 °C and sieve it through a 200-mesh sieve to complete the pretreatment of the foundry waste sand, aluminum ash and borax.

[0037] Add the pretreated foundry waste sand, aluminum ash and borax into a V-type mixer and stir at 20 r / min for 15 minutes to obtain a mixture. The mass ratio of the foundry waste sand, aluminum ash and borax is 6:3:1. Then, place the mixture in a ball mill and add anhydrous ethanol, where the anhydrous ethanol accounts for 15% of the mass of the mixture, and stir at 200 r / min for 6 hours to obtain a slurry. Place the slurry in a vacuum drying oven for drying. After drying, take it out and crush it in a small crusher and sieve it through a 200-mesh sieve to obtain a composite powder. Stir the composite powder and PVA solution with a magnetic stirrer. During the stirring process, the composite powder is added continuously and stirred at 500 r / min for 30 minutes to complete the preparation of the reinforcing agent.

[0038] The mass ratio of the composite powder to the PVA solution is 1:1, and the concentration of the PVA solution is 5%. During the preparation of the reinforcing agent, the set temperature of the vacuum drying oven is 60 °C and the vacuum degree is -0.1 MPa.

[0039] The steps of the welding process are as follows: After the nickel outer shell after melting treatment is roughly ground with a silicon carbide grinding wheel and then finely polished with 800-mesh sandpaper, after the grinding is completed, perform UT flaw detection and remove the abnormal products. After cleaning the nickel rear cover, place the nickel rear cover on the end face of the qualified nickel outer shell, place it inside a vacuum welding box, and weld the nickel outer shell and the nickel rear cover by argon arc welding using the same welding wire as the nickel rear cover. After cooling, take it out and grind the weld bead to be flush with the outer diameter of the nickel outer shell to complete the welding process of the nickel outer shell.

[0040] The steps of the extrusion process are as follows: Place the nickel outer shell after the welding process in a high-temperature resistance furnace and heat it at a rate of 5 °C / min to 920 °C and then hold for 2 hours. Take it out and place it in a 1500T extruder to extrude it from the die to obtain a nickel-coated copper rod. The diameter of the die orifice is 28 mm. After the nickel-coated copper rod cools, cut the head and tail of the nickel-coated copper rod and draw the nickel-coated copper rod to the required size through a cold drawing process to complete the extrusion process.

[0041] The reduction ratio of the diameter in each cold drawing process is less than 6.3%, the drawing speed is 2 m / min, and high-temperature annealing is carried out in an annealing furnace every 2 draws. The annealing temperature is 680 °C for 2 h.

[0042] Example 2:

[0043] A method for manufacturing a metallurgically bonded nickel-coated copper rod and wire, comprising the following steps:

[0044] Step 1: Copper core preparation. Select T1 oxygen-free copper powder and borax binder, stir, extrude and polish to complete the copper core preparation;

[0045] Step 2: Outer shell preparation. Select a nickel rod, cut it and process it into shape to obtain a nickel outer shell and a nickel rear cover;

[0046] Step 3: Melting treatment. Prepare the reinforcing agent, clean the inside of the nickel outer shell and apply the reinforcing agent, then put the copper core into the inside of the nickel outer shell and send it into a vacuum melting furnace for sealed melting treatment;

[0047] Step 4: Welding treatment. Perform flaw detection on the nickel outer shell after melting treatment, and vacuum weld the nickel outer shell after flaw detection and the nickel rear cover through a vacuum welding box;

[0048] Step 5: Extrusion treatment. Put the welded nickel outer shell into a high-temperature resistance furnace for heating and then extrude it through an extruder to obtain a nickel-coated copper rod. After cooling, cut the head and tail of the nickel-coated copper rod, and then draw the nickel-coated copper rod to the required size through a cold drawing process to complete the preparation.

[0049] The steps of copper core preparation are to stir T1 oxygen-free copper powder and borax binder to obtain a mixed powder. The mass ratio of T1 oxygen-free copper powder to borax binder is 20:3. Put the mixed powder into the forming die of a hydraulic press for extrusion molding, take it out and polish it with 800-mesh sandpaper to complete the copper core preparation.

[0050] The outer shell preparation includes the following steps. The nickel outer shell is selected as a nickel rod with a diameter of 125 mm, cut and processed into shape, with a length of 290 mm. One end of the nickel outer shell is processed into an arc head with an R of 87.5, and the arc chamfer at the tangent of the arc and the processed outer diameter surface is R32.5. At the other end of the nickel outer shell, a hole with a diameter of 75 mm is processed at one end of the cross-section. The shape of the front end of the hole is the same as the outer diameter, and a 20×25° chamfer is processed on the outer diameter at the drilling end. The nickel rear cover is selected and processed after cutting from a 125-mm nickel rod. The cutting length is 30 mm, the diameter is processed to 120 mm, the length is processed to 25 mm, and one end is chamfered at 20×25°.

[0051] The steps of the smelting treatment are as follows: wipe the inner hole of the nickel shell with industrial alcohol 3-5 times, and coat the inner hole of the nickel shell with the reinforcing agent through a spraying device, with a coating thickness of 80-100 microns. After loading the copper core into the nickel shell, send it into a vacuum melting furnace, continuously inject argon into the vacuum melting furnace until the argon in the furnace accounts for 99.8% of the furnace space, and the purity of argon is greater than 99.9%. The vacuum melting furnace is heated to 1300°C at a rate of 7.5°C / min and kept for 3 hours, and then cooled to room temperature. During the cooling process, when the temperature is greater than 80°C, keep the argon continuously filled until the temperature of the vacuum melting furnace is lower than 60°C, stop filling argon, and take out the nickel shell to complete the smelting treatment.

[0052] The preparation method of the reinforcing agent is as follows: select foundry waste sand, aluminum ash and borax for pretreatment. After crushing and screening the foundry waste sand, soak it in a 10% dilute hydrochloric acid solution for 40 minutes, then wash it with deionized water until neutral, and dry it with a dryer for standby. Place the aluminum ash in a muffle furnace, heat it to 800°C at a rate of 10°C / min and forge for 2 hours. After taking it out and cooling, ball-mill the forged aluminum ash with a planetary ball mill at a speed of 350 r / min for 4 hours, and sieve it through a 200-mesh sieve, with zirconia balls as the medium, and the mass ratio of zirconia balls to aluminum ash is 4:1. Dehydrate the industrial-grade borax at 200°C and sieve it through a 200-mesh sieve to complete the pretreatment of the foundry waste sand, aluminum ash and borax.

[0053] Add the pretreated foundry waste sand, aluminum ash and borax into a V-type mixer, stir at 30 r / min for 15 minutes to obtain a mixture. The mass ratio of the foundry waste sand, aluminum ash and borax is 6:3:1. Place the mixture in a ball mill, add anhydrous ethanol, and anhydrous ethanol accounts for 15% of the mass of the mixture. Stir at 250 r / min for 6 hours to obtain a slurry. Place the slurry in a vacuum drying oven for drying. After drying, take it out and crush it in a small crusher, and sieve it through a 200-mesh sieve to obtain a composite powder. Stir the composite powder and PVA solution with a magnetic stirrer. During the stirring process, the composite powder is added continuously, and stir at 550 r / min for 35 minutes to complete the preparation of the reinforcing agent.

[0054] The mass ratio of the composite powder to the PVA solution is 1:1, the concentration of the PVA solution is 5%, the set temperature of the vacuum drying oven during the preparation of the reinforcing agent is 60°C, and the vacuum degree is -0.1 MPa.

[0055] The steps of the welding process are as follows: After the nickel outer shell after smelting treatment is roughly ground with a silicon carbide grinding wheel and then finely polished with 800-mesh sandpaper, after the grinding is completed, non-conforming products are removed after UT flaw detection. After cleaning the nickel rear cover, the nickel rear cover is placed on the end face of the qualified nickel outer shell and placed inside a vacuum welding box. The nickel outer shell and the nickel rear cover are welded by argon arc welding using the same welding wire as the nickel rear cover. After cooling, it is taken out and the weld bead is ground to be flush with the outer diameter of the nickel outer shell, completing the welding process of the nickel outer shell.

[0056] The steps of the extrusion process are as follows: The nickel outer shell after welding treatment is placed in a high-temperature resistance furnace and heated to 920°C at a rate of 7.5°C / min and then held for 2 hours. It is taken out and extruded from a die by a 1500T extruder to obtain a nickel-clad copper bar. The diameter of the die orifice is 28 mm. After the nickel-clad copper bar is cooled, the head and tail of the nickel-clad copper bar are cut, and the nickel-clad copper bar is drawn to the required size through a cold drawing process, completing the extrusion process.

[0057] In the cold drawing process, the reduction ratio of the diameter in each drawing is less than 6.3%, the drawing speed is 3.5 m / min, and high-temperature annealing is carried out in an annealing furnace every 3 draws, with the annealing temperature being 700°C for 2 hours.

[0058] Example 3:

[0059] A method for manufacturing a metallurgically bonded nickel-clad copper bar and wire includes the following steps:

[0060] Step 1: Copper core preparation. Select T1 oxygen-free copper powder and borax binder, stir, extrude, and grind to complete the preparation of the copper core.

[0061] Step 2: Outer shell preparation. Select a nickel rod, cut it, and process it into shape to obtain a nickel outer shell and a nickel rear cover.

[0062] Step 3: Smelting treatment. Prepare the reinforcing agent, clean the inside of the nickel outer shell, apply the reinforcing agent, then load the copper core into the nickel outer shell, and send it into a vacuum melting furnace for sealed smelting treatment.

[0063] Step 4: Welding treatment. Conduct flaw detection on the nickel outer shell after smelting treatment, and vacuum-weld the nickel outer shell after flaw detection and the nickel rear cover through a vacuum welding box.

[0064] Step 5: Extrusion treatment. Load the welded nickel outer shell into a high-temperature resistance furnace for heating and then extrude it through an extruder to obtain a nickel-clad copper bar. After cooling, cut the head and tail of the nickel-clad copper bar, and draw the nickel-clad copper bar to the required size through a cold drawing process to complete the preparation.

[0065] The steps for preparing the copper core are as follows: Stir T1 oxygen-free copper powder and borax binder to obtain a mixed powder. The mass ratio of T1 oxygen-free copper powder to borax binder is 20:3. Add the mixed powder into the forming die of a hydraulic press for extrusion molding. After taking it out, polish it with 800-mesh sandpaper to complete the preparation of the copper core.

[0066] The preparation of the outer shell includes the following steps: Select a nickel rod with a diameter of 125 mm for the nickel outer shell, cut it and process it into shape with a length of 290 mm. Process an R87.5 arc head at one end of the nickel outer shell. The arc chamfer at the tangent point of the arc and the processed outer diameter surface is R32.5. At the other end of the nickel outer shell, process a hole with a diameter of 75 mm at one end of the cross-section. The shape of the front end of the hole is the same as the outer diameter. Process a 20×25° chamfer at the outer diameter of the drilling end. Select a 125 mm nickel rod for the nickel rear cover, cut it and process it. The cutting length is 30 mm, the diameter is processed to 120 mm, and the length is processed to 25 mm. Chamfer one end at 20×25°.

[0067] The steps for melting treatment are as follows: Wipe the inner hole of the nickel outer shell 5 times with industrial alcohol, and coat the inner hole of the nickel outer shell with a strengthening agent through a spraying device. The coating thickness is 100 microns. After loading the copper core into the nickel outer shell, send it into a vacuum melting furnace. Continuously inject argon into the vacuum melting furnace so that the argon in the furnace accounts for 99.8% of the furnace space, and the purity of argon is greater than 99.9%. The vacuum melting furnace is heated to 1350°C at a rate of 10°C / min and kept for 3 h, and then cooled to room temperature. During the cooling process, when the temperature is greater than 80°C, keep the argon continuously filled until the temperature of the vacuum melting furnace is lower than 60°C, and then stop filling argon and take it out to complete the melting treatment of the nickel outer shell.

[0068] The preparation method of the strengthening agent is as follows: Select foundry waste sand, aluminum ash, and borax for pretreatment. After crushing and screening the foundry waste sand, soak it in a 10% dilute hydrochloric acid solution for 30 - 40 min, then wash it with deionized water until it is neutral, and dry it with a dryer for standby. Place the aluminum ash in a muffle furnace and forge it at a rate of 10°C / min to 800°C for 2 h. After taking it out and cooling, ball-mill the forged aluminum ash with a planetary ball mill at a speed of 350 r / min for 4 h, and sieve it with a 200-mesh sieve. The medium is zirconia balls, and the mass ratio of zirconia balls to aluminum ash is 4:1. Dehydrate industrial-grade borax at 200°C and sieve it with a 200-mesh sieve to complete the pretreatment of foundry waste sand, aluminum ash, and borax.

[0069] Specifically, the foundry waste sand contains silicon dioxide and aluminum oxide, and the aluminum ash contains aluminum, aluminum nitride, and aluminum oxide.

[0070] The pretreated foundry waste sand, aluminum ash, and borax are added to a V-type mixer and stirred at 40 r / min for 15 min to obtain a mixture. The mass ratio of the foundry waste sand, aluminum ash, and borax is 6:3:1. The mixture is then placed in a ball mill, and absolute ethanol is added. The absolute ethanol accounts for 15% of the mass of the mixture, and it is stirred at 300 r / min for 6 h to obtain a slurry. The slurry is placed in a vacuum drying oven for drying. After drying, it is taken out and placed in a small crusher for crushing, and then sieved through a 200-mesh sieve to obtain a composite powder. The composite powder and the PVA solution are stirred by a magnetic stirrer. During the stirring process, the composite powder is added continuously and stirred at 600 r / min for 40 min to complete the preparation of the reinforcing agent.

[0071] The mass ratio of the composite powder to the PVA solution is 1:1, and the concentration of the PVA solution is 5%. During the preparation of the reinforcing agent, the set temperature of the vacuum drying oven is 60°C, and the vacuum degree is -0.1 MPa.

[0072] The welding treatment steps are as follows: After the nickel outer shell after melting treatment is roughly ground with a silicon carbide grinding wheel and then finely polished with 800-mesh sandpaper, after the polishing is completed, UT flaw detection is carried out to remove abnormal products. After the nickel rear cover is cleaned, the nickel rear cover is placed on the end face of the qualified nickel outer shell and placed inside a vacuum welding box. The nickel outer shell and the nickel rear cover are welded by argon arc welding using the same welding wire as the nickel rear cover. After cooling, it is taken out and the weld bead is polished to be consistent with the outer diameter of the nickel outer shell to complete the welding treatment of the nickel outer shell.

[0073] The steps of the extrusion treatment are as follows: The nickel outer shell after welding treatment is placed in a high-temperature resistance furnace and heated to 920°C at a rate of 10°C / min and then held for 2 h. It is taken out and placed in a 1500T extruder to be extruded from the die to obtain a nickel-clad copper rod. The diameter of the die orifice is 28 mm. After the nickel-clad copper rod is cooled, the head and tail of the nickel-clad copper rod are cut, and the nickel-clad copper rod is drawn to the required size through a cold drawing process to complete the extrusion treatment.

[0074] In the cold drawing process, the reduction ratio of the diameter in each drawing is less than 6.3%, the drawing speed is 5 m / min, and high-temperature annealing is carried out in an annealing furnace every 4 draws. The annealing temperature is 720°C and lasts for 2 h.

[0075] The difference between Comparative Example 1 and Example 1 is that: In this comparative example, foundry waste sand is not added to the reinforcing agent.

[0076] The difference between Comparative Example 2 and Example 1 is that: In this comparative example, aluminum ash is not added to the reinforcing agent.

[0077] The difference between Comparative Example 3 and Example 1 is that: In this comparative example, neither aluminum ash nor foundry waste sand is added to the reinforcing agent.

[0078] The difference between Comparative Example 4 and Example 1 lies in that: in this comparative example, a nickel-coated copper rod produced by a conventional interference fit is used.

[0079] Performance test: Perform performance tests on the metallurgically bonded nickel-coated copper rods and wires prepared in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4. Bonding strength test: Evaluate the interfacial hardness through nanoindentation test; High-temperature stability test: Observe whether cracks or delamination occur at the interface through an aging test at 400 °C for 100 hours; Directivity test: Measure the resistivity of the nickel-coated copper rod by the four-probe method.

[0080] The obtained test data are recorded in the following table:

[0081]

[0082] It can be seen that the bonding strength, high-temperature stability, and conductivity of the metallurgically bonded nickel-coated copper rods and wires prepared in Comparative Examples 1, 2, 3, and 4 are all lower than those in Examples 1, 2, and 3. This shows that the manufacturing method of the metallurgically bonded nickel-coated copper rods and wires of the present invention not only has good bonding strength but also excellent high-temperature stability and conductivity. This indicates that the manufacturing method of the metallurgically bonded nickel-coated copper rods and wires provided by the present invention has a broader market prospect and is more suitable for popularization.

[0083] In the description of this specification, the descriptions referring to terms such as "one embodiment", "example", "specific example", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0084] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not elaborate on all the details, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art in the relevant technical field can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for manufacturing a metallurgically bonded nickel-coated copper rod or wire, characterized in that: It includes the following steps: Step 1: Copper core preparation. Select T1 oxygen-free copper powder and borax binder, stir, extrude and polish to complete the copper core preparation; Step 2: Shell preparation. Select a nickel rod, cut it and process it into a shape to obtain a nickel shell and a nickel rear cover; Step 3: Melting treatment. Prepare a reinforcing agent, clean the inside of the nickel shell, apply the reinforcing agent, then put the copper core into the inside of the nickel shell, and send it into a vacuum melting furnace for sealed melting treatment; Step 4: Welding treatment. Perform flaw detection on the nickel shell after melting treatment, and vacuum weld the nickel shell after flaw detection and the nickel rear cover through a vacuum welding box; Step 5: Extrusion treatment. Put the welded nickel shell into a high-temperature resistance furnace for heating, then extrude it through an extruder to obtain a copper-clad nickel rod. After cooling, cut the head and tail of the copper-clad nickel rod, and then draw the copper-clad nickel rod to the required size through a cold drawing process to complete the preparation.

2. The method for manufacturing a metallurgically bonded nickel-coated copper rod or wire according to claim 1, characterized in that, The steps of the copper core preparation are to stir T1 oxygen-free copper powder and borax binder to obtain a mixed powder. The mass ratio of the T1 oxygen-free copper powder to the borax binder is 20:

3. Put the mixed powder into the forming die of a hydraulic press for extrusion molding, take it out and polish it with 800-mesh sandpaper to complete the copper core preparation.

3. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 1, characterized in that, The shell preparation includes the following steps. The nickel shell is selected as a nickel rod with a diameter of 125 mm, cut and processed into a shape, with a length of 290 mm. One end of the nickel shell is processed into an arc head with an R87.5 arc, and the arc chamfer at the tangent of the arc and the processed outer diameter surface is an R32.5 arc chamfer. At the other end of the nickel shell, a hole with a diameter of 75 mm is processed at one end of the cross section. The shape of the front end of the hole is the same as the outer diameter, and a 20×25° chamfer is processed on the outer diameter at the drilling end. The nickel rear cover is selected and processed after cutting on a 125-mm nickel rod, with a cutting length of 30 mm, the diameter is processed to 120 mm, and the length is processed to 25 mm, and one end is chamfered at 20×25°.

4. The method for manufacturing a metallurgically bonded nickel-coated copper rod or wire according to claim 1, characterized in that, The steps of the melting treatment are as follows: Wipe the inner hole of the nickel shell with industrial alcohol 3-5 times, and coat the reinforcing agent on the inner hole of the nickel shell through a spraying device. The coating thickness is 80-100 microns. After putting the copper core into the inside of the nickel shell, send it into a vacuum melting furnace, continuously inject argon into the vacuum melting furnace so that the argon in the furnace accounts for 99.8% of the furnace space. The purity of the argon is greater than 99.9%. The vacuum melting furnace is heated to 1250-1350°C at a rate of 5-10°C / min and kept for 3 hours, and then cooled to room temperature. During the cooling process, when the temperature is greater than 80°C, keep the argon continuously filled until the temperature of the vacuum melting furnace is lower than 60°C, then stop filling the argon and take it out to complete the melting treatment of the nickel shell.

5. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 1, characterized in that, The preparation method of the enhancer is as follows: Select foundry waste sand, aluminum ash and borax for pretreatment. After crushing and screening the foundry waste sand, soak it in a 10% dilute hydrochloric acid solution for 30 - 40 min, then wash it with deionized water until neutral, and dry it with a dryer for standby. Place the aluminum ash in a muffle furnace, heat it at a rate of 5 - 10 °C / min to 800 °C and forge for 2 h. After taking it out and cooling, ball-mill the forged aluminum ash with a planetary ball mill at a speed of 250 - 350 r / min for 4 h, and sieve it through a 200-mesh sieve. The medium is zirconia balls, and the mass ratio of zirconia balls to aluminum ash is 4:

1. Dehydrate the industrial-grade borax at 200 °C and sieve it through a 200-mesh sieve to complete the pretreatment of the foundry waste sand, aluminum ash and borax.

6. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 5, characterized in that, Add the pretreated foundry waste sand, aluminum ash and borax into a V-type mixer, stir at 20 - 40 r / min for 15 min to obtain a mixture. The mass ratio of the foundry waste sand, aluminum ash and borax is 6:3:

1. Place the mixture in a ball mill and add absolute ethanol, where the absolute ethanol accounts for 15% of the mass of the mixture, and stir at 200 - 300 r / min for 6 h to obtain a slurry. Place the slurry in a vacuum drying oven for drying. After drying, take it out and crush it in a small crusher, and sieve it through a 200-mesh sieve to obtain a composite powder. Stir the composite powder and PVA solution with a magnetic stirrer. During the stirring process, the composite powder is added continuously, and stir at 500 - 600 r / min for 30 - 40 min to complete the preparation of the enhancer.

7. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 6, characterized in that, The mass ratio of the composite powder to the PVA solution is 1:1, the concentration of the PVA solution is 5%, and the set temperature of the vacuum drying oven during the preparation of the enhancer is 60 °C, and the vacuum degree is -0.1 MPa.

8. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 1, characterized in that, The welding treatment steps are as follows: After rough grinding the melted nickel shell with a silicon carbide grinding wheel, finely polish it with 800-mesh sandpaper. After the grinding is completed, remove the abnormal products after UT flaw detection. After cleaning the nickel back cover, place the nickel back cover on the end face of the qualified nickel shell, place it inside a vacuum welding box, and weld the nickel shell and the nickel back cover by argon arc welding using the same welding wire as the nickel back cover. After cooling, take it out and grind the weld bead to be consistent with the outer diameter of the nickel shell to complete the welding treatment of the nickel shell.

9. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 1, characterized in that, The steps of the extrusion treatment are as follows: Place the welded nickel shell in a high-temperature resistance furnace, heat it at a rate of 5 - 10 °C / min to 920 °C and keep it warm for 2 h. Take it out and extrude it from the mold with a 1500T extruder to obtain a nickel-clad copper rod. The diameter of the die orifice is 28 mm. After the nickel-clad copper rod cools, cut the head and tail of the nickel-clad copper rod, and draw the nickel-clad copper rod to the required size through a cold drawing process to complete the extrusion treatment.

10. The method for manufacturing a metallurgically bonded nickel-coated copper bar or wire according to claim 9, characterized in that, The proportion of diameter reduction in each cold drawing process of the cold drawing process is less than 6.3%, the drawing speed is 2 - 5 m / min, and high-temperature annealing is carried out in an annealing furnace every 2 - 4 draws. The annealing temperature is 680 - 720 °C for 2 h.

Images