JPH0475207A - Inorganic insulated wire - Google Patents

Abstract

PURPOSE:To improve corrosion resistance, insulation and flexibility by applying anode oxidation treatment to the surface of a conductor wire provided with an aluminium surface layer while giving a solution containing a ceramics precurser to the pores of an insulating oxidation film. CONSTITUTION:An inorganic insulation wire 10 is provided with a heat-resisting aluminium alloy wire 11. An insulating oxidation film 14 is formed on the surface of a heat-resisting aluminium alloy wire 11 by means of anode oxidation treatment. The outer layer part of this insulating oxidation film 14 is given hole sealing treatment with insulating ceramics powder and thereby a hole sealing layer 15 is formed. An insulating ceramics layer 16 is formed on the insulating oxidation film 14. In this way, an insulation coating is composed only of an inorganic material being excellent in heat resistance and having no deterioration in an insulating characteristic. Further, it has big dielectric breakdown voltage and excellent flexibility. since the surface is smooth, there occures no problem of emission and adsorption of gas.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to inorganic insulated wires, and in particular, inorganic insulated wires that can be used in high temperature, high vacuum environments, radiation environments, or corrosive environments. It relates to insulated wires.

[Prior Art] Insulated wires conventionally used for internal wiring and windings in devices are mainly coated with organic materials, and for applications that require particularly high heat resistance, fluororesin is used. Electric wires coated with insulation such as polyimide or polyimide are used. However, even with such heat-resistant wires,
Its usage limit is about 300°C at most. Therefore, if such an electric wire is continued to be used above this temperature, the coating material may thermally decompose, resulting in dielectric breakdown.

For this reason, electric wires insulated with inorganic materials, such as alumite electric wires obtained by anodizing aluminum wires and electric wires whose conductors are coated with ceramics by vacuum evaporation, etc., are being considered.

In addition, in semiconductor manufacturing equipment, high-vacuum equipment used for high-energy experiments, plasma experiments, etc., because decomposed gases generated from organic materials are disliked, conductors are simply passed through ceramic insulators, or glass tape is applied to the conductors. A rolled one is used.

In addition, in environments where radiation exists or corrosive environments such as acids or alkalis, MI cables ( Mineral In5ula
ted Cable) is used.

[Problems to be Solved by the Invention] However, the above-mentioned electric wires coated with inorganic materials have various problems.

For example, anodized wire must be anodized thickly in order to obtain a high dielectric breakdown voltage, but wires that have been anodized this thick are not flexible and can crack when bent. This will cause dielectric breakdown. On the other hand, if a thin layer is anodized to increase flexibility, a sufficient dielectric breakdown voltage cannot be obtained.

Furthermore, electric wires whose conductors are coated with ceramics using a vacuum evaporation method or the like cannot be bent because the adhesion of the coating film is small.

Furthermore, wires that are passed through ceramic insulators or wrapped with glass tape have the trouble of having to be manually processed.

Further, since ME cables generally have a large wire diameter, they are inferior in compactness and flexibility.

Furthermore, as mentioned above, when organic materials are used as insulation coatings, gas release due to thermal decomposition becomes a problem, especially in high vacuum. If it has a surface, gas adsorption becomes a problem.

Therefore, an object of the present invention is to provide an inorganic insulated wire that can solve the conventional problems as described above.

[Means for Solving the Problems] The present invention is directed to an inorganic insulated wire including a conductor wire comprising aluminum or an aluminum alloy in at least a surface layer. It is characterized by adopting the following configuration.

That is, the insulating coating includes an insulating oxide film formed on the surface of the conductor wire by anodizing, an insulating ceramic powder that seals the pores of the insulating oxide film, and a ceramic precursor on the insulating oxide film. A ceramic layer is formed by applying a solution containing the material and turning it into a ceramic.

[Function] The anodic oxidation treatment for forming the above-mentioned insulating oxide film is carried out in, for example, a sulfuric acid bath, a phosphoric acid bath, a chromic acid bath, an oxalic acid bath, or the like. In order to control the thickness of the insulating oxide film formed, it is preferable to control the electrolytic current to a constant value (constant current operation).

If, in order to obtain a high dielectric breakdown voltage, the thickness of the insulating oxide film is increased by, for example, performing large current treatment and/or long-time treatment, flexibility will be lost. Therefore, it is preferable to make the thickness of the insulating oxide film to be formed to be, for example, 5% or less of the diameter of the conductor wire, and to provide flexibility while sacrificing dielectric breakdown voltage to some extent.

This reduced insulation is compensated for by sealing the pores of the insulating oxide film with insulating ceramic powder.

Further, the above-mentioned pores existing in the insulating oxide film tend to adsorb various gases, and therefore are not preferable for use in a high vacuum. Therefore, in this respect as well, there is significance in sealing the pores of the insulating oxide film. This sealing treatment is preferably performed by a powder electrodeposition method using insulating ceramic powder. Insulating ceramic powders that can be used include Al2O3, AIN, BN, SiO2, Si
C.

There are powders such as Si3N4, TiO2, ZrO2, etc.

Through this pore sealing treatment, pores that degrade the insulation properties of the insulating oxide film or become sources of gas adsorption are blocked, and
At the same time, corrosion resistance is also improved.

Furthermore, an insulating ceramic layer is formed on the insulating oxide film in order to supplement the retention of the insulating ceramic powder used for sealing the pores. By forming this insulating ceramic layer, the surface of the obtained inorganic insulated wire is made smoother. This insulating ceramic layer is formed by applying a solution containing a ceramic precursor on the insulating oxide film and turning it into a ceramic. A solution containing a metal alkoxide or a metal carboxylic acid ester containing one or more metals selected from the group consisting of one or more metals is used, or an aqueous solution that dissolves water glass is used.

The inorganic insulated wire thus formed has corrosion resistance,
It has excellent insulation and flexibility, and has a smooth surface.

[Example] FIG. 1 shows an inorganic insulated wire 1 according to an example of the present invention.
0 is shown in cross-section.

Referring to FIG. 1, the inorganic insulated wire 10 is made of Al-0,0
A heat-resistant aluminum alloy wire 11 such as a 5% Zr alloy wire is provided. An insulating oxide film 14 is formed on the surface of the heat-resistant aluminum alloy wire 11 by anodizing. The outer layer portion of this insulating oxide film 14 is sealed with insulating ceramic powder, thereby forming a sealing layer 15. An insulating ceramic layer 1 is formed on the insulating oxide film 14.
6 is formed.

FIG. 2 shows an inorganic insulated wire 2 according to another embodiment of the present invention.
FIG.

Referring to FIG. 2, the inorganic insulated wire 20 includes an aluminum-covered copper conductor wire 21. As shown in FIG. This aluminum-clad copper conductor wire 21 is formed by fitting aluminum 23 to an oxygen-free copper wire 22. An insulating oxide film 24 is formed on the surface of such aluminum-covered copper conductor wire 21 by anodizing treatment. A sealing layer 25 obtained by sealing an insulating ceramic powder is formed on the outer layer portion of the insulating oxide film 24 . An insulating ceramic layer 26 is formed on the insulating oxide film 24.

In this way, in the above-mentioned inorganic insulated wires 10 and 20, in order to provide the desired flexibility, the insulating oxide films 14 and 24 formed by anodizing are made thinner, thereby reducing the insulation properties. , supplemented with a sealing treatment using insulating ceramic powder (sealing treatment layers 15 and 25), and further supplemented with insulating ceramic layers 16 and 2.
6 is provided to further improve insulation and smooth the surface.

FIG. 3 is a schematic diagram of an apparatus used to manufacture the above-mentioned inorganic insulated wire 10 or 20.

Referring to FIG. 3, the conductor wire 30 to be treated is supplied from a supply section 31 to a degreasing tank 32, where it is degreased. Subsequently, the conductor wire 30 to be treated is introduced into the anodizing treatment tank 33.
An insulating oxide film is formed on the surface by electrolytic treatment.

Next, the conductor wire 30 to be processed is cleaned in a cleaning tank 34.

Next, the conductor wire 30 to be treated is introduced into the electrodeposition tank 35.

In this electrodeposition tank 35, insulating ceramic powder is electrophoretically deposited in order to seal the pores of the insulating oxide film formed on the surface of the conductor wire 30 to be processed. More specifically, a mixture of acetone and water at a volume ratio of 10:1 is used as a dispersion medium for the insulating ceramic powder, and the ceramic powder is dispersed by a method such as mechanical stirring or air stirring.

Here, iodine is added as a charging agent, a DC voltage is applied using a stainless steel plate or the like as an anode, ceramic powder is electrodeposited on the insulating oxide film of the conductor wire 30 to be treated, and the insulating oxide film is sealed. Note that since the pore diameter of the insulating oxide film is generally small, the size of the insulating ceramic powder is preferably at a level of, for example, 1 μm or less.

The conductor wire 30 to be treated that has left the electrodeposition bath 35 is dried in a dryer 36.

Next, a solution containing a ceramic precursor is applied to the conductor wire 30 to be processed in a coating bath 37, and then this is turned into a ceramic in a baking bath 38 to form an insulating ceramic layer.

The inorganic insulated wire 30a thus obtained is wound up by a winding machine 39.

Experimental examples carried out according to the present invention will be described below.

(Experimental Example 1) A JIS 1070 aluminum wire having a wire diameter of 0.5 mm was prepared and degreased using trichlene. Next, in a 38% phosphoric acid aqueous solution kept at 45°C, an electrolytic current of 15
Electrolytic treatment was performed at A/dm2 for 2 minutes. An insulating oxide film with a thickness of 10 μm was formed on the surface of the wire treated in this way.

Next, the following operation was performed as a pore sealing treatment.

Acetone and water were mixed in a volume ratio of 10:1, and this solution I
For L, the average particle size is 0. 50g1 of 7μm SiC
1 g of iodine was added, and the powder was electrodeposited in a bath with air stirring, using a stainless steel plate as an anode, and applying DC 200 V.

Furthermore, the process of applying a solution containing a ceramic precursor to the outside of the insulating oxide film and heat-treating it at 500° C. for 10 minutes in the atmosphere was repeated five times. The coating solution used here was a solution obtained by reacting a mixed solution containing 5 mol% tributoxyaluminum, 10 mol% triethanolamine, 5 mol% water, and 80 mol% isopropyl alcohol at 50°C for 1 hour. Met.

The thickness of the final film formed through these processes is 1
It was 4 μm. Furthermore, when the surface roughness of the film was measured, the Ra value specified by JIS was 0.09 μm. In addition, the dielectric breakdown voltage of the obtained inorganic insulated wire was 100
OV, and for flexibility, the bending diameter is 15
mm was achieved.

(Experimental Example 2) A wire made of a heat-resistant aluminum alloy and having a wire diameter of 1 mm was prepared. After degreasing this wire using trichlene, 35
In a 10% chromic anhydride aqueous solution kept at ℃, the electrolytic current was 2.
Electrolytic treatment was performed at OA/dm2 for 1 minute. An insulating oxide film with a thickness of 12 μm was formed on the surface of the wire treated in this way.

Next, the following operation was performed as a pore sealing treatment.

Mix acetone and water at a volume ratio of 10:1, and add this solution 1
”, the average particle size is 0. 40 μm At203
1 g of g1 iodine was added, and the powder was electrodeposited in a bath with air agitation, using a stainless steel plate as an anode, and applying DC 200 V.

Furthermore, on the outside of this insulating oxide film, commercially available water glass 3
After applying an aqueous solution diluted to 10 wt%, it was dried at room temperature, followed by heat treatment at 70°C for 10 minutes and at 150°C for 30 minutes, and then coated with a 10 wt% diluted nitric acid aqueous solution. The operation of soaking for 5 minutes was repeated twice.

The thickness of the final film formed through these processes is 1
The surface roughness of the film was 0.08 μm in Ra value specified by JIS.

Furthermore, the dielectric breakdown voltage of the obtained inorganic insulated wire was 1100
V, and in terms of flexibility, the bending diameter is 20m.
m has been achieved.

(Experiment Example 3) On the outside of the heat-resistant aluminum alloy, 1050 according to JIS
Wire diameter 1mm coated with aluminum with a thickness of 80μm
I prepared a line. After degreasing this wire using trichlene, it was electrolytically treated for 1 minute at an electrolytic current of 30 A/dm2 in a 45% aqueous oxalic acid solution kept at 40°C. An 8 μm thick insulating oxide film was formed on the surface of the treated wire.

Next, the following operation was performed as a pore sealing treatment.

Mix acetone and water at a volume ratio of 10:1, and add this solution 1
t, 30 g of BN with an average particle size of 0.5 μm and 1 g of iodine were added, and the powder was electrodeposited in an air-stirred bath while applying DC 200 V using a stainless steel plate as an anode.

Furthermore, the process of applying a solution containing a ceramic precursor to the outside of the insulating oxide film and heat-treating it at 500° C. for 10 minutes in the air was repeated seven times. The coating liquid used here was a toluene solution (4% Zr) of zirconium naphthenate, which is commercially available under the trade name "Zirconium naphthenate" manufactured by Nippon Kagaku Sangyo Co., Ltd., and diluted twice with toluene. It was stirred day and night.

The thickness of the final film formed through these processes is 1
The surface roughness of the film was 0.07 μm in Ra value specified by JIS.

In addition, the dielectric breakdown voltage of the obtained inorganic insulated wire was 1050
V, and in terms of flexibility, the bending diameter is 15m.
I was able to achieve m.

(Experimental Example 4) A wire having a wire diameter of 1 mm and having a thickness of 84 μm coated with 1050 aluminum according to JIS was prepared on the outside of oxygen-free copper. After degreasing this wire using trichlene,
Electrolytic current 30A/dm in 23% sulfuric acid aqueous solution maintained at
2 for 1 minute. An insulating oxide film with a thickness of 11 μm was formed on the surface of the wire treated in this way.

Next, the following operation was performed as a pore sealing treatment.

Mix acetone and water at a volume ratio of 10:1, and add this solution 1
For comparison, 50 g of SiO2 with an average particle size of 0.7 μm
1 g of iodine was added, and the powder was electrodeposited in an air-stirred atmosphere using a stainless steel plate as an anode while applying DC 200 V.

Furthermore, the process of applying a solution containing a ceramic precursor to the outside of this insulating oxide film and heat-treating it at 350° C. for 20 minutes in the atmosphere was repeated five times. The coating liquid used here contained 8 mol% of tetrabutyl orthosilicate.
32 mol% water, 60 mol% isopropyl alcohol
Nitric acid was added dropwise in an amount equal to 3/100 of the number of moles of tetrabutyl orthosilicate to the mixed solution containing 8
This is a solution that was reacted at 0°C for 2 hours.

The thickness of the final film formed through these processes is 1
4 μm, and the surface roughness of the film was 0.09 μm in Ra value specified by JIS. Furthermore, the dielectric breakdown voltage of the obtained inorganic insulated wire was 1100 V, and the bending diameter was 15 mm in terms of flexibility.

[Effects of the Invention] As described above, according to the present invention, since the insulating coating is composed only of inorganic materials, it has excellent heat resistance, and therefore does not thermally decompose even at high temperatures. There is no deterioration in characteristics. Furthermore, it has a high dielectric breakdown voltage and excellent flexibility. Furthermore, since the surface is smooth, there are no problems with gas release or adsorption.

[Brief explanation of the drawing]

FIG. 1 shows an inorganic insulated wire 10 according to an embodiment of the present invention.
FIG. FIG. 2 shows an inorganic insulated wire 2 according to another embodiment of the present invention.
FIG. FIG. 3 is a schematic diagram of an apparatus used for manufacturing an inorganic insulated wire 30a according to the present invention. In the figure, 10, 20, 30a are inorganic insulated wires, 11
is heat-resistant aluminum alloy wire, 23 is aluminum, 14
．． 24 is an insulating oxide film, 15 and 25 are sealing layers, 16
．． 26 is an insulating ceramic layer, 21 is an aluminum-covered copper conductor wire, 22 is an oxygen-free copper wire, 30 is a conductor wire to be treated, 3
3 is an anodizing tank, 35 is an electrodeposition tank, 37 is a coating tank, and 38 is a baking tank.

Claims (5)

[Claims] (1) A conductor wire having at least a surface layer of aluminum or an aluminum alloy, an insulating oxide film formed on the surface of the conductor wire by anodizing treatment, and an insulating ceramic powder sealing the pores of the insulating oxide film. An inorganic insulated wire, comprising: an insulating ceramic layer formed by applying a solution containing a ceramic precursor onto the insulating oxide film and converting the solution into a ceramic. (2) The insulating ceramic powder is Al_2O_3
, AlN, BN, SiO_2, SiC, Si_3N_4
The inorganic insulated wire according to claim 1, wherein the inorganic insulated wire is at least one powder selected from the group consisting of , TiO_2 and ZrO_2. (3) the insulating ceramic powder is applied so as to seal the pores of the insulating oxide film by a powder electrodeposition method;
The inorganic insulated wire according to claim 1 or 2. (4) The solution containing the ceramics precursor is Si, A
4. The inorganic insulated wire according to claim 1, wherein the inorganic insulated wire is a solution containing a metal alkoxide or metal carboxylic acid ester containing one or more metals selected from the group consisting of Zr, Ti, Zr, and Mg. (5) The inorganic insulated wire according to any one of claims 1 to 3, wherein the solution containing the ceramic precursor is an aqueous solution that dissolves water glass.