JPH0388215A - Inorganic insulator - Google Patents

Abstract

PURPOSE:To get an inorganic insulator whose heat resistance and insulating property are good by providing a conductor, a composite plated layer where eutectoid is caused with dispersion of inorganic compound fine grain provided on the surface of the conductor and an inorganic insulating layer installed on the surface of the composite plated layer. CONSTITUTION:A composite plated layer 2 is laid around a conductor 1, and inorganic compound fine grain 2a is dispersed in the composite plated layer 2, and an inorganic insulating layer 3 is installed around the composite plated layer 2. When the conductor 1 is used as wire for wiring or winding, it is preferable that the conductor 1 is Cu or Cu alloy which can provide high conductivity. When SiO2 or Al2O3 is used as the inorganic insulating layer 3 installed on the composite plated layer 2, it is preferable that SiC, AlN, Si3N4, Al2O3 and SiO2, etc., are used as the inorganic compound fine grain 2a of the composite plated layer 2. It is thereby possible to obtain an inorganic insulator which is good in insulating property, flexibility and heat resistance.

Description

[Detailed Description of the Invention] Field of Application of cSS] The present invention relates to an inorganic insulator such as an inorganic insulated wire that can be used, for example, for wiring or winding wire.

[Conventional technology]

BACKGROUND ART Wires in which a metal conductor is covered with an organic coating material are known as wiring wires and winding wires that have been commonly used in high vacuum equipment, high temperature equipment, and the like.

In particular, for applications that require heat resistance, irradiation-crosslinked resins,
Electric wires coated with a fluorine-containing resin such as tetrafluoroethylene or polyimide are used. However, the heat resistance of such resin-coated wires is at most 30
It is 0°C.

In the case of electric wires used in high vacuum equipment, heat resistance that can withstand heating such as baking treatment is required, and in order to achieve and maintain a high degree of vacuum, it is necessary to release adsorbed and absorbed gases and moisture. There is a need for electric wires that emit less gas due to thermal decomposition. Conventional organic materials? An overturned electric wire cannot satisfy such requirements for heat resistance and non-gassing properties.

For this reason, electric wires coated with inorganic materials are being considered, such as alumite electric wires in which the surface of an aluminum conductor is anodized and an AFL20s film is formed on the surface, electric wires made by electrodeposition, and even insulating ceramic wires. Electric wires coated with

[Problems to be Solved by the Invention] However, the electric wires that have been studied in the past have the following problems. That is, anodized electric wire i
Wires and electric wires made by electrodeposition cannot withstand temperatures of 660° C. or higher, even momentarily, because the metal that can be used as the conductor is limited to aluminum. Also, it cannot achieve high conductivity like copper.

Furthermore, even if copper is coated with insulating ceramics, copper has poor adhesion to ceramics.
Peeling of the ceramic layer on the surface, etc. occurred, and it could not be put to practical use.

The purpose of this invention is to solve such conventional problems,
The purpose of the present invention is to provide an inorganic insulator with excellent heat resistance and insulation properties.

[Means for Solving the Problems] The inorganic insulator of the present invention comprises a conductor, a composite plating layer provided on the surface of the conductor in which inorganic compound fine particles are dispersed and eutectoid, and a composite plating layer provided on the surface of the composite plating layer. and an inorganic insulating layer provided thereon.

FIG. 1 is a sectional view for explaining the present invention. FIG. 1 shows a cross section of an electric wire when the present invention is applied to an inorganic insulated electric wire. Referring to FIG. 1, a composite plating layer 2 is provided around a conductor 1. In the composite plating layer 2, inorganic compound fine particles 2a are dispersed. An inorganic insulating layer 3 is provided around this composite plating layer 2.

When used as an electric wire for wiring or winding, it is preferable that the conductor is Cu or a Cu alloy because high conductivity can be obtained. Furthermore, the surface of Cu or Cu alloy as a conductor may be plated with Ni or C. Oxidation of the conductor can be prevented by plating Ni or C around the Cu or Cu alloy as a conductor. can be achieved.

Further, the conductor may be not only a wire but also a tape-like elongated body.

In this invention, the method of plating the composite plating layer is not particularly limited. For example, various conventional plating methods such as electrolytic plating and electroless plating can be applied.

The metal of the composite plating layer is not particularly limited, and examples thereof include CuSNi and C''.

SiO2 is used as an inorganic insulating layer provided on the composite plating layer.
Alternatively, when AuzOs is used, the inorganic compound fine particles of the composite plating layer are SiC.

AIN, Si3N4, A view, 0. It is preferable to use 5L02 and 5L02.

The thickness of the composite plating layer is preferably 0.5 to 20 μm. The reason why the thickness is preferably 0.5 μm or more is because in the case of composite plating, only the metal precipitates immediately after the start of plating, and then particles begin to eutectoid. 5μ
This is because if it is less than m, it becomes difficult to disperse and eutectoid the inorganic compound fine particles. The reason why the thickness of the composite plating layer is preferably 20 μm or less is that flexibility is required when the inorganic insulator of the present invention is used for electric wires, etc., and if the thickness exceeds 20 μm, sufficient flexibility is required. This is because it may not be possible to obtain it.

In this invention, the thickness of the inorganic insulating layer is preferably 1 to 20 μm. The reason why the thickness of the inorganic insulating layer is preferably 1 μm or more is that if the thickness is not greater than this, it will be difficult to obtain a dielectric breakdown voltage of 100 V. Further, the reason why the thickness of the inorganic insulating layer is preferably 20 μm or less is that if the thickness exceeds this value, sufficient flexibility may not be obtained.

[Function] In the inorganic insulator of the present invention, a composite plating layer in which inorganic compound fine particles are dispersed and eutectoid is provided between the conductor and the inorganic insulating layer. Since this composite plating layer has inorganic compound fine particles dispersed therein, it has excellent adhesion to the inorganic insulating layer, and since it is a plating layer, it also has excellent adhesion to the conductor. - Therefore, the adhesion between the conductor and the inorganic insulating layer is improved and peeling becomes difficult. Therefore, an inorganic insulator with excellent flexibility can be obtained.

The metal of the composite plating layer may be Cu, but may also be Ni or Cr, which can be easily plated industrially. These metals have better adhesion to inorganic compounds than Cu. Furthermore, when Ni or C is used as a conductor, it also serves to prevent oxidation of the Cu or Cu alloy during high-temperature use.

Fine particles of inorganic compounds may appear on the surface of the composite plating layer, forming irregularities on the surface of the composite plating layer. In such cases, a wedge effect may occur on the inorganic insulating layer provided on the surface of the composite plating layer. This makes it easier to coat the inorganic insulating layer and improves the adhesion of the inorganic insulating layer to the composite plating layer.

Example C] Example 1 A nickel-plated copper wire with a thickness of 2 μm and a wire diameter of 1 mm was pretreated with vapor degreasing using perchlorethylene, and then placed in a 15:2:3 mixture of phosphoric acid: nitric acid: water. I etched it for 30 seconds.

This pretreated tough pitch copper wire with a wire diameter of 1 mm was mixed with sulfuric acid steel 7 g/L Rochelle salt 75 g/L) reethanolamine 10 m (1/L formalin 25 m (1/L sodium hydroxide 20 g/(1, sodium carbonate 10 g/L) g/
i, and Am20.i with a particle size of 8 μm or less in a copper plating bath containing 0.125 g/11 sodium cyanide. 5g of particles
/(L), and electroless composite plating was performed by immersing it in a plating bath while stirring with an air pump. At a bath temperature of 50°C, the deposition rate was 5 μm/hour, and the film of the composite plating layer Composite plating was performed until the thickness reached 15 μm.

The composite-plated wire was coated with A11203 to a thickness of 10 μm by arc plasma spraying to form an inorganic insulating layer.

Example 2 An oxygen-free copper wire with a wire diameter of 1 mm was subjected to the same pretreatment as in Example 1 above. Add 2.5 g/l each of SLC and SiO2 particles with a particle size of 2 μm or less to a nickel plating bath containing 2 cans of nickel sulfate, and while stirring with an air pump, the pretreated oxygen-free copper wire was placed in the plating bath. Composite plating was performed by immersing it in The bath temperature was 60°C, the wire was used as the cathode, the nickel plate was used as the anode, and the current density was 8A/dm2.
Composite plating was performed. The deposition rate was 6 μm/min, and composite plating was performed until the thickness of the composite plating layer was 6 μm.

Tetrabutyl orthosilicate diwater:isopropyl alcohol-2
Nitric acid was added at a ratio of 3/100 mole to tetrabutyl orthosilicate to a mixed solution at a molar ratio of 8:15, and a solution obtained by heating and stirring at 80° C. for 2 hours was applied. After application, the process of heating at 400°C for 10 minutes was repeated 5 times. As a result, a SiO2 layer with a thickness of 8 μm was formed as an inorganic insulating layer on the surface of the composite plating layer.

Example 3 A Cu-0.01% Zr wire with a wire diameter of 1 mm was used in Example 1 above.
Pretreatment was carried out in the same manner. Chromic anhydride 250g/garden,
A Q Ns S t 3 N4 with a particle size of 1 μm or less, and 5in2 with a particle size of 2 μm or less were added to 2.5 g of sulfuric acid/garden chromium plating bath, respectively, and 2 g/fL of Ig/I, Ig/i, and 2 g/fL were added. While stirring with a pump, the pretreated wire was immersed to perform composite plating on its surface. Plating was carried out at a bath temperature of 55° C. and a current density of 10 A/dm 2 using the wire as a cathode and the stainless steel plate as an anode. The deposition rate was 5 μm/min, and composite plating was performed until the thickness was 9 μm. On this composite plating layer, a 70% aqueous solution of No. 3 sodium silicate (water glass) was applied,
The process of heating at °C, washing with a 10% nitric acid aqueous solution, and drying was repeated 10 times.

As a result, S as an inorganic insulating layer is formed on the composite plating layer.
An iO2 layer was formed with a thickness of 10 μm.

Comparative example 1 111070 wire with a wire diameter of 1 mm at 30°C 10111% by weight
It was immersed in an aqueous sodium hydroxide solution for 30 seconds. Thereafter, it was immersed in a 23% by weight aqueous sulfuric acid solution at 38°C for anodization. A stainless steel plate is used as the cathode, and the current density is 2.5A/
Oxidized for 20 minutes at dm2. The thickness of the formed oxide film was 20 μm. The wire thus obtained was dried at 200° C. for 20 minutes.

Comparative Example 2 An oxygen-free copper wire with a wire diameter of 1 mm was subjected to the same pretreatment as in Example 1 above. This pretreated oxygen-free copper wire was directly arc plasma sprayed without composite plating to a thickness of 10 μm.
An inorganic insulating layer of AfL203 of m was formed.

For the wire rods of Examples 1 to 3 and Comparative Examples 1 and 2 obtained as above, the dielectric breakdown voltage, bending diameter, allowable temperature limit, high temperature strength, and electrical conductivity were measured, and the obtained results are shown in Table 1. It is also shown in .

(Hereinafter, blank spaces) As is clear from Table 1, Examples 1 to 3 according to the present invention
Comparing the insulated wires of Comparative Example 1 using the conventional method of anodic oxidation, the insulated wires of Examples 1 to 3 were superior in breakdown voltage, had smaller bending diameters, and had better flexibility. It can be seen that it is also excellent. Furthermore, since copper wire is used as the conductor, it has excellent electrical conductivity.

It also has excellent strength at high temperatures.

Comparing Examples 1 to 3 according to the present invention and Comparative Example 2 in which no composite plating layer was provided, there is no significant difference in dielectric breakdown voltage, but there is a significant difference in bending diameter. It can be seen that the insulated wires of Examples 1 to 3 exhibit excellent flexibility. It also has excellent heat resistance and high temperature strength, and Examples 1 to 1 according to the present invention
It can be seen that No. 3 has excellent heat resistance.

In the above embodiments, a case has been described in which the inorganic insulator of the present invention is applied to an insulated wire, but the present invention can also be applied to uses other than wires.

[Effects of the Invention] As explained above, the inorganic insulator according to the present invention is significantly superior in insulation, flexibility, and heat resistance to conventional electrical wires. Therefore, it can be used for heat-resistant applications such as around automobile engines, windings, wiring inside vacuum machines, radiation-resistant applications, etc.

[Brief explanation of drawings]

FIG. 1 is a sectional view for explaining the present invention. In the figure, 1 is a conductor, 2 is a composite plating layer, 2a is an inorganic compound fine particle, and 3 is an inorganic insulating layer.

Claims (9)

[Claims] (1) An inorganic insulator comprising: a conductor; a composite plating layer provided on the surface of the conductor in which inorganic compound fine particles are dispersed and eutectoid; and an inorganic insulating layer provided on the surface of the composite plating layer. (2) Claim 1, wherein the conductor is Cu, a Cu alloy, or a Cu alloy plated with Ni or Cr.
Inorganic insulators described in . (3) The inorganic insulator according to claim 1, wherein the conductor is a long body. (4) The inorganic insulator according to claim 3, wherein the elongated body is a wire or a tape. (5) The metals of the composite plating layer are Cu, Ni and C.
The inorganic insulator according to claim 1, which is at least one metal selected from the group consisting of r. (6) The inorganic compound fine particles of the composite plating layer are SiC
, AlN, Si_3N_4, Al_2O_3 and Si
At least one species selected from the group consisting of O_2,
The inorganic insulator according to claim 1. (7) The inorganic insulator according to claim 1, wherein the composite plating layer has a thickness of 0.5 to 20 μm. (8) The inorganic insulating layer is made of SiO_2 and/or Al.
The inorganic insulator according to claim 1, comprising _2O_3. (9) The inorganic insulator according to claim 1, wherein the inorganic insulating layer has a thickness of 1 to 20 μm.