JP2009099450A - Manufacturing method of aluminum oxide coated insulated aluminum electric wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of efficiently producing an alumite electric wire superior in wear resistance and flexibility or the like. <P>SOLUTION: After forming an anodic oxidized coat on the surface of an aluminum elemental wire by treating anodic oxidation coating on aluminum wire 1 in an electrolytic liquid 32, the elemental wire is subjected to a pore-sealing treatment by putting in boiling water such as in a steam tank 4 or in a vapor pressure container, then, a heat treatment is carried out. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a method for efficiently producing an aluminum oxide-coated insulated aluminum electric wire that does not require an insulation coating, has a high heat resistance, and is a lightweight heat-resistant electric wire, which is more excellent in wear resistance, flexibility, etc. About.

  Insulated wires with excellent heat resistance are required for wires used in high-temperature atmospheres such as the engine room of automobiles and the vicinity of blast furnaces. Such an insulated wire is sometimes used in facilities that require safety at high temperatures, such as heating facilities and fire alarms, and is also used in an environment heated to a high temperature in an automobile.

As a heat-resistant electric wire, conventionally, a conductor mainly made of copper or a copper alloy is thinned by wire drawing, and this is coated with a thermoplastic resin such as polyvinyl chloride or polyethylene by extrusion molding. .
However, copper or copper alloy is the most suitable conductor material from the viewpoints of high electrical conductivity, ease of soldering, and strength, but copper has low resistance to oxidants and is at room temperature in the atmosphere. It is also oxidized or changes to the basic carbonate patina. Furthermore, under a high temperature environment, there has been a problem that oxidation proceeds and use as a conductor becomes impossible.

  Conventionally, an alumite electric wire in which an anodized oxide film is provided on an aluminum conductor has been proposed and developed (Patent Document 1).

JP-A-9-63359 (2nd page)

However, conventional alumite electric wire manufacturing techniques have not been able to efficiently produce products with sufficient wear resistance, flexibility and the like.
In view of the above-described problems, the present invention provides a technique capable of efficiently producing an alumite electric wire having more excellent wear resistance, flexibility, and the like.

As a result of intensive studies, the present inventor has solved the above-described drawbacks of the conventional techniques by adopting the following configuration.
That is, the present invention is as follows.

(1) Anodizing the aluminum strand in the electrolytic solution to form an anodic oxide film on the surface of the aluminum strand, and then sealing it in boiling water or a steam pressure vessel, followed by heat treatment The manufacturing method of the aluminum oxide film insulation aluminum wire to perform.
(2) The method for producing an aluminum oxide-coated insulated aluminum electric wire according to (1), wherein enamel coating is performed after the heat treatment.
(3) The method for producing an aluminum oxide-coated insulated aluminum electric wire according to (1), wherein the electrolytic solution is sulfuric acid and the sulfuric acid concentration is 25 wt%.
(4) The method for producing an aluminum oxide-coated insulated aluminum electric wire according to (3), wherein the concentration of aluminum sulfate in the electrolytic solution is 12 to 13 g / l.
(5) The method for producing an aluminum oxide-coated insulated aluminum electric wire according to (1), wherein the temperature of the electrolytic solution is 15 to 20 ° C.
(6) The method for producing an aluminum oxide-coated insulated aluminum electric wire according to (1), wherein the current density during anodization is 3 to 15 A / dm ² and a pulse voltage is 10 to 15 V.

  By the production method of the present invention, an aluminum oxide-coated insulated aluminum electric wire having more excellent wear resistance, flexibility and the like can be efficiently produced.

The outline of the manufacturing method of the aluminum oxide film insulation aluminum electric wire of this invention is shown in FIG.
The aluminum strand 1 as a conductor material is usually drawn with a die 2 to obtain a thin aluminum conductor 11. The aluminum element wire 1 may be any one as long as an oxide film can be formed by anodization treatment, and may be pure aluminum or an aluminum alloy. The oxide film is preferably formed uniformly on the surface.

  The aluminum element wire is provided with an aluminum oxide film as an insulating film instead of an insulating film made of resin. As a method for forming an oxide film, an electrolytic solution 32 such as an aqueous solution of sulfuric acid, aqueous solution of phosphoric acid, aqueous solution of oxalic acid or aqueous solution of chromic acid in the anodizing bath 31 of the anodizing apparatus 3 is used for the thin aluminum conductor 11 shown in FIG. In general, an anodic oxidation treatment by an electrolysis method in which an electrode is immersed in the solution as an anode and an electrode immersed in the solution is used as a cathode is generally used.

An anodizing treatment suitable for the method for producing an aluminum oxide-coated insulated aluminum wire of the present invention is performed under the following conditions using a cathode as graphite and an anode as an aluminum conductor.
(1) The electrolyte is composed of an acid and a salt, and as the inorganic acid, sulfuric acid or oxalic acid or other organic acid is used. Particularly desirable conditions are a sulfuric acid concentration of 25 wt% and an aluminum sulfate concentration of 12 to 13 g / l. With this condition, the film growth is performed smoothly.
(2) The liquid temperature of the electrolytic solution is preferably 15 to 20 ° C., and the corrosion resistance decreases at lower or higher temperatures. The wear resistance improves as the temperature decreases, but it is desirable that the temperature range be within the above range in view of the balance with the corrosion resistance.
(3) The current density is preferably 3 to 15 A / dm ² , and the voltage application condition is preferably a pulse voltage of 10 to 15 V. As current density increases, film thickness variation and “burn (brown discoloration)” and “powder blowing” occur on the surface, so a high current is passed as a pulse voltage for a short time to prevent temperature rise and “burn”. The growth of the aluminum oxide film is promoted.
An example of a pulse voltage waveform is shown in FIG.

Since there are oxide films by anodizing treatment, usually 0.01 to 0.05 μm and about 60 to 800 pores / μm ² , sealing treatment is performed.
The sealing treatment in the present invention is performed in boiling water or a steam pressure vessel such as the steam tank 4.
In the case of continuous treatment, the anodized aluminum electric wire is put in boiling water, and in the case of batch treatment, the coil 6 is used as a winding coil 13 and then placed in a steam pressure vessel.
Processing conditions such as processing time and steam pressure are appropriately determined according to a desired dielectric breakdown voltage.

The film thickness of the aluminum oxide film is preferably 20 to 100 mm, and if it is less than 20 mm, the film is broken and short-circuited depending on the operating voltage, and if it is thicker than 100 mm, bending workability is deteriorated and crack generation and productivity are lowered.
In order to obtain a film thickness of 20 to 100 mm, the aluminum oxide film-insulated aluminum electric wire after the sealing treatment is subjected to heat treatment as a post-process. By heat treatment, the aluminum oxide film grows at an accelerated rate, and an insulating film having a very strong and excellent wear resistance is formed. The heat treatment temperature is preferably about 450 to 600 ° C.

Since the aluminum oxide layer is not energized, it is not covered and can be used as an electric wire. However, when it is used for applications in which flexibility is particularly required, an enamel coating process is performed between the heat treatment process and the accumulator 5. It is desirable to provide.
As a technique for enamel coating, a conventionally known technique can be adopted. As enamel coating, conventional alkyd resins (epoxy-modified melamine resin, urethane-modified resin, silicone-modified resin, acrylic-modified resin, etc.), polyimide, and polyamideimide are used.

The aluminum oxide-coated insulated aluminum wire obtained by the production method of the present invention is inexpensive and can be used as a single wire or a tubed wire as an insulated wire having good heat resistance, electrical insulation, and heat dissipation.
It can be used for automotive parts, machine parts, control and sensor related magnet wires, heat-resistant magnet wires for audio equipment, etc. Furthermore, aluminum and aluminum oxide have low thermal neutron absorption and are indispensable for neutron research. Although it is a material that cannot be used, there is a possibility of application expansion to a neutron acceleration / deceleration device using this characteristic.

It is a figure which shows the outline of the manufacturing method of this invention. It is a figure which shows the waveform example of the pulse voltage in the case of the electrolysis of an anodizing process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum strand 11 Small diameter aluminum conductor 2 Dies 3 Anodizing apparatus 31 Anodizing tank 32 Electrolytic solution 4 Water vapor tank 5 Accumulator 6 Coiler

Claims (6)

  An aluminum oxide is formed by anodizing an aluminum wire in an electrolytic solution to form an anodic oxide film on the surface of the aluminum wire, sealing in boiling water or a steam pressure vessel, and then performing a heat treatment A method for producing a coated insulated aluminum electric wire.   The method for producing an aluminum oxide-coated insulated aluminum electric wire according to claim 1, wherein enamel coating is performed after the heat treatment.   3. The method for producing an aluminum oxide coated insulated aluminum wire according to claim 2, wherein the electrolytic solution is sulfuric acid and the sulfuric acid concentration is 25 wt%.   4. The method for producing an aluminum oxide-coated insulated aluminum wire according to claim 3, wherein the concentration of aluminum sulfate in the electrolytic solution is 12 to 13 g / l.   The method for producing an aluminum oxide-coated insulated aluminum electric wire according to claim 1, wherein the temperature of the electrolytic solution is 15 to 20 ° C. The method for producing an aluminum oxide-coated insulated aluminum electric wire according to claim 1, wherein the current density at the time of anodizing is 3 to 15 A / dm ² and the pulse voltage is 10 to 15 V.

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