JP2008229703A - Method of manufacturing copper-coated aluminum wire and copper-coated aluminum wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a copper-coated aluminum wire, by which the thickness of copper on the surface can be adjusted to arbitrary thickness and, further, the copper-coated aluminum wire whose area rate of copper is less than 10% can be manufactured at low cost. <P>SOLUTION: In the manufacturing process of the copper-coated aluminum wire including a copper coating step where a composite wire 3 of the copper-coated aluminum wire is manufactured by coating copper on an aluminum wire 1 and a drawing step where the composite wire of the copper-coated aluminum wire is thinned down to a prescribed diameter, the process has a copper layer polishing step where the thickness of the copper layer 2 is adjusted to a prescribed thickness by reducing the thickness of the copper layer 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a copper-coated aluminum wire, and more particularly to a method for producing a copper-coated aluminum wire capable of arbitrarily adjusting the thickness of copper on the surface.

  Conventionally, copper coated aluminum wire with copper coated aluminum wire on pickup coil for hard disk, which is lighter than copper wire and requires high conductivity, central conductor of coaxial cable for CATV, winding for headphones, etc. Is used.

  As shown in Table 1, this copper-coated aluminum wire has a copper area ratio of 10%, 15%, and 20% so that the copper area ratio is 10%, 15%, and 20% mainly from the viewpoint of weight reduction and conductivity. It is compounded.

This copper-coated aluminum wire is usually manufactured through the following steps.
The first step is a step of producing a composite wire of a copper-coated aluminum wire by combining copper as a covering material and an aluminum wire as a core material, and is performed by a pipe making method or a pipe cladding method.

  In the pipe making method, an aluminum wire is vertically attached to the copper tape, the copper tape is continuously formed into a tubular shape by roll forming so as to cover the aluminum wire, and the butted portion of the copper tape is continuously welded. By further reducing the diameter of the copper tape formed in a tubular shape with a roll, the copper tape is in close contact with the inner aluminum wire to produce a composite wire of copper-coated aluminum wire.

  In addition, in the pipe clad method, an aluminum wire slightly thinner than the inner diameter is inserted into a copper pipe of a predetermined thickness, and the copper pipe and the aluminum wire are integrated into a die and drawn (drawing) with a die, so that they are in close contact with each other Thus, a composite wire of copper-coated aluminum wire is manufactured.

  In the next step, the composite wire of the obtained copper-coated aluminum wire is drawn to reduce the diameter to a predetermined diameter. In addition, the same wire drawing machine as that for a normal copper wire is used, and a heat treatment for removing processing distortion may be performed in the middle. Further, in the case where the wire drawing is performed up to the final wire diameter, heat treatment may be performed to soften the copper layer or the aluminum wire depending on the application.

As a method for producing a copper-coated aluminum wire by such a copper wire coating process and a wire drawing process, for example, Patent Document 1 is disclosed.
JP-A-11-57848

  By the way, of the copper-coated aluminum wires shown in Table 1, those with a copper area ratio of 15% have been most often manufactured. From the viewpoint of weight reduction and difficulty in manufacturing, the copper area ratio is 10% and 20%. For copper-coated aluminum wires, production was very small.

  However, the need for copper-coated aluminum wires having a copper area ratio of 10% or less is increasing for further weight reduction in recent years. In addition, with the diversification of applications, there is an increasing need for a copper-coated aluminum wire having an intermediate copper area ratio of a conventional product such as a copper area ratio of 12%.

However, in the conventional manufacturing method, it is difficult to increase / decrease (adjust) the area ratio of the copper layer in the wire drawing process or the heat treatment process. The thickness of the copper tape or copper pipe, the diameter of the aluminum wire, or the like in accordance with the copper area ratio is selected each time.
For this reason, when manufacturing copper-coated aluminum wires having various copper area ratios, copper tapes, copper pipes, and aluminum wires corresponding to the respective copper area ratios are required, which makes it difficult to store and manage these materials. In addition, there is a problem that the material cost increases due to the small amount of various kinds.

  In particular, in the production of a copper-coated aluminum wire having a copper area ratio of 10% or less, since the copper layer is extremely thin, it has been difficult to produce by the conventional method.

For example, when manufacturing a composite wire by a pipe making method, the butting portion is welded while continuously forming an extremely thin copper tape by roll forming, so the forming area and welding conditions are such that the copper area ratio is 10%. Compared to the standard product that exceeds, it is limited to a very narrow range, and because of many welding defects, the yield was also poor.
Even in the case of the pipe clad method, it is extremely difficult to combine thin copper pipes and aluminum wires, and if the copper pipes are bent or damaged, the copper pipes can be easily torn when the aluminum wires are inserted, so the yield is It was bad.

  Furthermore, for a copper-coated aluminum wire having a copper area ratio of 10% or less, the wire drawing conditions in the wire drawing step are required to be very strictly controlled. In the wire drawing of copper-coated aluminum wire, the adhesion (bondability) between the copper layer on the surface and the aluminum wire is extremely poor at the initial stage where the wire drawing degree is 70% or less, and the variation varies depending on the location. During processing, the copper layer peeled off from the aluminum wire, and the aluminum wire was often exposed and disconnected.

  Such peeling of the copper layer and disconnection of the aluminum wire are more likely to occur as the copper area ratio is lower and the copper layer is thinner. Therefore, in the production of a copper-coated aluminum wire having a copper area ratio of 10% or less, the yield is low. The actual situation is that extreme reductions and cost increases are inevitable.

  The present invention has been made in view of the above problems, and can adjust the thickness of the copper layer on the surface to an arbitrary thickness, and can further produce a copper-coated aluminum wire having a copper area ratio of less than 10% at a low cost. It aims at providing the manufacturing method of an aluminum wire, and the copper covering aluminum wire manufactured by this manufacturing method of a copper covering aluminum wire.

  That is, the invention according to claim 1 is a copper coating step of manufacturing a composite wire of a copper-coated aluminum wire by coating copper on an aluminum wire, and reducing the composite wire of the copper-coated aluminum wire to a predetermined diameter. In the manufacturing process of the copper covering aluminum wire which has a wire drawing process to perform, it has the copper layer grinding | polishing process which reduces the thickness of the said copper and adjusts to predetermined thickness, It is characterized by the above-mentioned.

  The copper layer polishing step for adjusting the copper thickness may be provided during the step of drawing the composite wire of the copper-coated aluminum wire to the final wire diameter, or after the wire drawing to the final wire diameter. May be.

  The invention described in claim 2 is the method for producing a copper-coated aluminum wire according to claim 1, wherein the copper thickness adjustment is performed by at least one of chemical polishing, physical polishing, and electrolytic polishing, or It is characterized by being performed by a combination of any two or more methods.

Here, chemical polishing is a method of chemically thinning the copper layer using a chemical polishing liquid. Examples of the chemical polishing liquid include sulfuric acid / hydrogen peroxide system, sulfuric acid / water system, and sulfuric acid / sodium dichromate. System, ammonium persulfate / water system, sulfuric acid / nitric acid system, sulfuric acid / hydrochloric acid / nitric acid system, sodium cyanide / hydrogen peroxide system, sulfuric acid / hydrochloric acid system, ferric chloride / hydrochloric acid system, ferric chloride / water system, peroxidation An acid treatment solution such as hydrogen water / water system is used.
Physical polishing is, for example, a method in which an abrasive such as a grindstone or a polishing cloth with abrasive grains is relatively moved while being in contact with a copper-coated aluminum wire and physically thinned. The thing using the kinetic energy of a grain may be used.
The electrolytic polishing is a method of electrochemical polishing in an electrolytic solution such as NaCl, NaClO ₃ , NaNO _{3, and the} like, and is a method in which copper is eluted and thinned on the principle opposite to electroplating.

  The invention according to claim 3 is produced by the method for producing a copper-coated aluminum wire according to any one of claims 1 and 2, and is a copper-coated aluminum wire having a copper area ratio of less than 10%. It is.

  According to the present invention, since the copper layer polishing step for arbitrarily adjusting the thickness of the copper on the surface is provided, in the first step, a copper-coated aluminum wire having a high productivity and a large copper area ratio is manufactured, and the wire drawing process is performed. It is possible to manufacture a copper-coated aluminum wire having a small copper area ratio by reducing the thickness of copper in the copper layer polishing step after the wire drawing process to the final wire diameter.

  As a result, a copper-clad aluminum wire having an intermediate copper area ratio (for example, a copper area ratio of 12%) is obtained using a conventional standard copper-coated aluminum wire such as a copper area ratio of 15% or 20% as a base material. As a matter of course, a copper-coated aluminum wire having a copper area ratio of less than 10% can be manufactured at a low cost and with a high yield. Thereby, it is possible to sufficiently cope with various uses of the copper-coated aluminum wire that is diversified and to further reduce the weight of the copper-coated aluminum wire.

  Hereinafter, an embodiment of a manufacturing method of a copper covering aluminum wire by the present invention is described based on a drawing.

FIG. 1 shows a manufacturing process of a copper-coated aluminum wire according to the present embodiment.
As shown in FIG. 1, in the first copper coating process, a copper layer 2 is formed on an aluminum wire 1 that is a core material by a known pipe making method or pipe cladding method, thereby forming a composite wire of copper-coated aluminum wire. 3 is manufactured, and then the composite wire 3 of the copper-coated aluminum wire is thinned to a predetermined diameter in the wire drawing step, and the original wire 4 is manufactured.

  The copper coating process and the wire drawing process are the same as those of the conventional method, but in this embodiment, a copper layer polishing process is newly provided at the end of the wire drawing process or in the middle of the wire drawing process, so The product line 5 in which the copper area ratio is adjusted to a predetermined value is manufactured by polishing the layer 2.

  Hereinafter, a method for adjusting the thickness of the copper layer 2 of the original wire 4 in the copper layer polishing step will be described with reference to FIGS.

FIG. 2 shows an example of adjusting the thickness of the copper layer 2 by chemical polishing.
As shown in FIG. 2, the original wire 4 fed out from the original wire reel 6 is subjected to degreasing, water washing, pickling and water washing steps, and then the surface copper layer 2 is dissolved by the chemical polishing liquid in the chemical polishing step. Then, the thickness of the copper layer 2 is adjusted. After adjusting the thickness of the copper layer 2, the original wire 4 is wound around a product take-up reel 7 as a product wire 5 through steps of washing with water, neutralization, and rust prevention.

  Examples of chemical polishing liquids include sulfuric acid / hydrogen peroxide, sulfuric acid / water, sulfuric acid / sodium dichromate, ammonium persulfate / water, sulfuric acid / nitric acid, sulfuric acid / hydrochloric acid / nitric acid, sodium cyanide / peroxide. Acid treatment solutions such as hydrogen, sulfuric acid / hydrochloric acid, ferric chloride / hydrochloric acid, ferric chloride / water, hydrogen peroxide / water are used.

Next, FIG. 3 shows an example of the thickness adjustment of the copper layer 2 by physical polishing.
As shown in FIG. 3, the thickness of the copper layer 2 is adjusted by stripping off the copper layer 2 on the surface of the primary wire 4 fed from the primary reel 6 in the physical polishing process. After adjusting the thickness of the copper layer 2, the original wire 4 is wound around the product take-up reel 7 as a product wire 5 through the steps of water washing, neutralization, water washing, and rust prevention.

  In the physical polishing step, for example, polishing with a grindstone or a polishing cloth interposing abrasive grains, polishing by sandblasting, or the like is performed. At the time of polishing, a fine polishing material such as a grindstone and abrasive grains is used so as not to damage the surface of the original wire 4.

Next, FIG. 4 shows an example of adjusting the thickness of the copper layer 2 by electropolishing.
As shown in FIG. 3, the original wire 4 fed out from the original reel 6 is subjected to degreasing, water washing, pickling and water washing steps, and then the surface copper layer 2 is eluted with an electrolytic solution in the electrolytic polishing step. By doing so, the thickness of the copper layer 2 is adjusted. After adjusting the thickness of the copper layer 2, the original wire 4 is wound around a product take-up reel 7 as a product wire 5 through steps of water washing, neutralization, water washing, and rust prevention.

In the electrolytic polishing process, for example, NaCl, NaClO ₃ , NaNO ₃ or the like is used as an electrolytic solution, and copper is eluted on the principle opposite to that of electroplating.

As described above, in the copper layer polishing step in the method for producing a copper-coated aluminum wire of this embodiment, any two or more of the above-described chemical polishing, physical polishing, and electrolytic polishing may be combined.
For example, first, the thickness of the copper layer 2 may be roughly reduced by physical polishing, and then the thickness of the copper layer 2 may be finely adjusted by chemical polishing or electrolytic polishing. The thickness of the copper layer 2 may be adjusted by the reverse procedure.

As a specific example, when a copper-coated aluminum wire is used for a hard disk pickup coil, a headphone winding or the like, the outer diameter of the coil is approximately 0.2 mm or less, so the thickness of the copper layer 2 to be reduced is several μm. It becomes the level of. Therefore, in this case, first, the copper layer 2 is thinned by several μm by chemical polishing, and further, smoothing is performed for coating the surface of the copper layer with enamel etc. by electrolytic polishing in the next step.
As another specific example, when a copper-coated aluminum wire is used as a central conductor of a coaxial cable for CATV, etc., the outer diameter is about 1.0 mm or more. Become a level. Therefore, in this case, the copper layer 2 is first sharply cut by physical polishing to reduce the thickness, and then the surface is smoothed while finely adjusting the thickness of the copper layer 2 by chemical polishing or electrolytic polishing. .

  Thus, according to this embodiment, since the copper layer polishing step for arbitrarily adjusting the thickness of the copper layer 2 on the surface is provided in the manufacturing process of the copper-coated aluminum wire, the first copper coating step is a production process. In addition to producing a composite wire 3 of a copper-coated aluminum wire having a good copper area ratio, the thickness of the copper layer 2 in the copper layer polishing step after the wire drawing process or after drawing to the final wire diameter. It is possible to manufacture a copper-coated aluminum wire (that is, product line 5) having a small copper area ratio.

As a result, a copper-clad aluminum wire having an intermediate copper area ratio (for example, a copper area ratio of 12%) is obtained using a conventional standard copper-coated aluminum wire such as a copper area ratio of 15% or 20% as a base material. As a matter of course, a copper-coated aluminum wire having a copper area ratio of less than 10% can be manufactured at a low cost and with a high yield. Thereby, it is possible to sufficiently cope with various uses of the copper-coated aluminum wire that is diversified and to further reduce the weight of the copper-coated aluminum wire.
The surface property of the copper-coated aluminum wire is preferably smoother for reasons such as the subsequent coating of an insulating layer such as enamel and the reason for reducing the starting point of breakage during handling. It is preferable to use polishing.

Hereinafter, the Example of the manufacturing method of the copper covering aluminum wire by this invention is described. Needless to say, the present invention is not limited to these examples.
Example 1

For chemical polishing of copper-coated aluminum wires, H ₂ SO ₄ / H ₂ O ₂ -based (sulfuric acid / hydrogen peroxide-based) chemical polishing solution is used. Manufactured. The manufacturing process is shown in Table 2.

As shown in Table 2, in the first copper coating process, an aluminum wire having an outer diameter of 9.5 mm is coated with a copper tape having a thickness of 0.4 mm and welded to form an outer diameter of 10 mm and a copper area. A composite wire of 15% copper coated aluminum wire was produced.
Next, in the wire drawing step, this copper-coated aluminum wire composite wire was drawn to an outer diameter of φ0.12 mm, and this was used as the original wire.
Next, the copper layer polishing process (chemical polishing step), the composition _{5~7% H 2 SO 4 / 10~12} % H 2 O 2, the polishing liquid temperature 40 to 50 ° C. using, according to the step of FIG. Then, the raw wire was chemically polished. In this chemical polishing step, the polishing time was finely adjusted so that the original wire having an outer diameter of φ0.12 mm was φ0.114 mm in the final product line.

About the product line manufactured through the said process, the average thickness of the copper layer was measured from the cross section, and the area ratio of copper was calculated from the total cross-sectional area. As a result of the calculation, the copper area ratio was 5.1%, which coincided with the measurement result of the conductivity, and the one satisfying the target was obtained.
(Example 2)

  As a polishing material for physical polishing, a PVA elastic grindstone (manufactured by NIPPON KENKEN) made by dispersing and mixing GC # 1000 and PVA (polyvinyl alcohol) is used, and a NaCl system is used as an electrolytic solution for electrolytic polishing. A copper-coated aluminum wire having an outer diameter of 0.205 mm and a copper area ratio of 5% was produced. The manufacturing process is shown in Table 3.

As shown in Table 3, in the first copper coating step, as in Example 1, an aluminum wire having an outer diameter of 9.5 mm was coated with a copper tape having a thickness of 0.4 mm and welded by a pipe making method. A composite wire of copper-coated aluminum wire having a diameter of 10 mm and a copper area ratio of 15% was manufactured.
Next, in the wire drawing step, the copper-coated aluminum wire composite wire was drawn to an outer diameter of φ0.217 mm, which was used as the original wire.
Next, in the copper layer polishing step, first, physical polishing was performed on the original wire, and the original wire was processed into an outer diameter φ0.207 mm and a copper area ratio of 6 to 7%. As physical polishing conditions, the original wire was run at a linear speed of 200 m / min and a tension of 2.0 kgf, and the PVA elastic grindstone was pressed against the original wire, and physical polishing was performed according to the process of FIG.

About the original wire which performed physical polishing, the average thickness of the copper layer was measured from the cross section, and the area ratio of copper was calculated from the total cross section. As a result of the calculation, the copper area ratio was 6.5%, which was consistent with the conductivity measurement result.
Next, electrolytic polishing was performed on the original wire after the physical polishing in accordance with the process of FIG. 4 to produce a product line having an outer diameter of 0.205 mm and a copper area ratio of 5%.
As conditions for electropolishing, a raw wire was run through a NaCl electrolyte heated to 70 ° C., and the electrolysis time was adjusted so that the current density was ² to 5 A / dm ² .

  About the product line manufactured through the said process, the average thickness of the copper layer was measured from the cross section, and the area ratio of copper was calculated from the total cross-sectional area. As a result of the calculation, the copper area ratio was 5.2%, which coincided with the measurement result of the conductivity, and the one satisfying the target was obtained.

  Since the copper-coated aluminum wire obtained by the production method of the present invention is lightweight and has high conductivity, it can be widely used for a pickup coil for a hard disk, a coaxial cable center conductor for CATV, a winding for headphones, and the like.

It is process drawing which shows the manufacturing method of the copper covering aluminum wire by this invention. It is a figure which shows the chemical polishing process in the manufacturing method of the copper covering aluminum wire by this invention. It is a figure which shows the physical polishing process in the manufacturing method of the copper covering aluminum wire by this invention. It is a figure which shows the electropolishing process in the manufacturing method of the copper covering aluminum wire by this invention.

Explanation of symbols

1 Aluminum wire 2 Copper (copper layer)
3 Composite wire of copper-coated aluminum wire

Claims (3)

A copper-coated aluminum wire having a copper coating step of manufacturing a composite wire of a copper-coated aluminum wire by coating copper on the aluminum wire, and a wire drawing step of reducing the composite wire of the copper-coated aluminum wire to a predetermined diameter In the manufacturing process of
A method for producing a copper-coated aluminum wire, comprising: a copper layer polishing step for reducing the thickness of the copper and adjusting it to a predetermined thickness. 2. The copper-coated aluminum according to claim 1, wherein the copper thickness adjustment is performed by at least one of chemical polishing, physical polishing, and electrolytic polishing, or a combination of any two or more methods. Wire manufacturing method. A copper-coated aluminum wire having a copper area ratio of less than 10%, which is produced by the method for producing a copper-coated aluminum wire according to claim 1.

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