JPH0349109A - Inorganic insulating conductor - Google Patents

Abstract

PURPOSE:To obtain an inorganic insulated conductor with excellent corrosion resistance by providing a metal layer containing at least one kind of Ti, Nb and Ta and an oxide layer arranged around it on the outer periphery of a conducting substrate. CONSTITUTION:A material mainly made of Cu and dispersed with Al2O3 grains in the Cu alloy and containing one of Cr, Zr and Fe is used as a substrate 1, a layer 2 of at least one kind of Ti, Nb and Ta is covered on the outer periphery, and an oxide layer 3 is covered on it. One of silicone oxide, zirconium oxide and aluminum oxide is formed on it. These oxide insulating layers are formed by coating and heat-treating liquid precursors of metal oxides. The thickness of oxide insulating layers is preferably set to 1/2 of the diameter (or thickness) of the substrate 1. An inorganic insulated conductor with excellent flexibility, compactness and excellent heat resistance, noncombustibility and corrosion resistance is obtained, and the adhesion between the metal layer and the oxide insulating layer is improved.

Description

[Detailed description of the invention] [Before industrial use] This invention relates to an inorganic insulated conductor I-, especially in high vacuum fO conditions such as vacuum equipment and high temperature equipment, and in high temperature environments. 1゜' 2. Description of the Related Art Insulated wires as insulated conductors are sometimes used in equipment such as heating equipment and fire alarms that require excellent integrity under high temperatures. Insulated wires are also used in environments that are heated to high temperatures inside automobiles. As such insulated lanes, T-insulated wires in which the conductor is coated with a heat-resistant organic resin such as polyimide or fluorocarbon resin have been used.

However, insulated wires coated with such a-type resin can only be used at temperatures of up to 300°C. In addition, the coating easily deteriorates due to exposure to ultraviolet rays and radiation, and when the coating is damaged, conductor parts such as copper conductors and aluminum conductors are extremely easily oxidized and corroded.

When used in applications that require high heat resistance or in environments that require a high degree of vacuum, the heat resistance alone is insufficient in terms of heat resistance. It is also insufficient in terms of gas release properties and the like.

Therefore, ceramic insulated wires have a conductor passed through a tube, and heat-resistant alloy wire tubes made of stainless steel or other alloys filled with metal oxide fine particles such as magnesium oxide are used. Ml'r-pull (Mine
ral In5lated Cable) and the like have been used for such applications.

Examples of insulated wires that require heat resistance and iiJ flexibility include glass braided insulated wires that use woven glass fibers as an insulating member.

[Problems to be Solved by the Invention] However, the conventional insulation 7 whose heat resistance is improved by using a ceramic insulator tube is wire or M! Cables and the like have overcome the problem of poor flexibility, and also have the disadvantage of being compact.

Further, when the glass braided insulated wire is arranged in a fixed shape according to the intended use, there is a problem in that glass dust is generated from the glass fibers.

This glass dust can become a gas adsorption source, so if fj glass insulated wire is used under conditions that require a high degree of vacuum, the glass dust can become a gas adsorption source. , it was impossible to maintain a high degree of vacuum.

On the other hand, so-called alumite electric wires, which are aluminum or aluminum alloy wires subjected to anodizing treatment, have been known as insulated electric wires with good heat resistance, insulation properties, and heat dissipation properties. In this Fulmite lightning wire, its Ji% material is limited to Alconium-Mori. Further, the inorganic insulating layer formed on the base material is also limited to aluminum oxide. However, there is a problem in that it is not possible to select a suitable combination of the base material and the inorganic insulating layer for various uses. Furthermore, since the base material is made of aluminum, there is a problem in that the heat resistance is insufficient depending on the application, and it has been desired to improve the heat resistance of the metal part.

This invention was made to solve the above problems, and aims to provide an inorganic insulated conductor having the following features.

(a) High insulation properties in t% humidity and temperature environment.

(b) iiJ has excellent flexibility.

(e) Not equipped with a gas suction source.

(d) f! ! Being able to select a combination of base material and inorganic insulating layer suitable for each application.

(Means for Solving the Problems) The first invention of this application includes a base material having four surfaces and including an electrical conductor, and a base material formed on the outer peripheral surface of the base material,
The metal layer includes a metal layer of at least one of the following metals selected from the group consisting of Ta and B, and an oxide insulating layer provided around the metal layer.

In the first invention, it is preferable that an oxide layer of the metal is formed on the surface of the metal layer. By forming an oxide insulating layer on this metal oxide layer, adhesion with the oxide insulating layer can be improved. Further, it is preferable that the metal oxide layer is obtained by anodizing the surface of the metal layer.

In this first invention, the oxide insulating layer may include, for example, one containing at least one oxide selected from the group consisting of silicon oxide, zirconium oxide, and aluminum oxide.

Moreover, this oxide insulating layer is 1. It can be formed by applying a liquid precursor of a metal oxide and subjecting it to heat treatment. As such a method, for example, a so-called sol-gel method can be applied. The sol-gel method is a method in which an oxide layer is formed by applying a solution obtained by hydrolyzing and dehydrating an alkoxide to the outer surface to be formed and heat-treating the solution. Further, an oxide insulating layer can also be formed by using a metal carboxylic acid ester instead of the metal alkoxyl and heat-treating the coated ester.

Further, the liquid precursor of the metal oxide can also contain ceramic particles. By including ceramic particles in this manner, a thick oxide insulating layer can be easily formed, and the insulation properties can be improved.

In this first invention, it is preferable to use an alloy containing Cu as a main component as the base material. Moreover, oxide particles such as aluminum oxide can be dispersed in this Cu alloy. The Cu alloy preferably contains at least 2% by weight or less of at least one element selected from the group consisting of Cr%Zr and Fe.

Further, in the first invention, the thickness of the oxide insulating layer is preferably 1/2 or less of the diameter of the base material. By making the thickness of the oxide insulating layer equal to or less than i/2 of the diameter or thickness of the base material, excellent flexibility and convertibility can be imparted.

The inorganic insulated conductor of the second invention of this application has a base material having an outer surface and containing an electrical conductor, and is formed on the outer surface of the base material, and includes Ti, V, Y%Zr, Nb5La, Hf5Ta, W,
At least one selected from the group consisting of Ags and Sn
The device includes a metal layer containing a different type of metal, an anodized layer formed on the metal layer, and an oxide insulating layer formed on the anodic oxidized layer by a sol-gel method.

In this second invention, the oxide insulating layer is made of silicon oxide,
Preferably, the material contains at least one oxide selected from the group consisting of zirconium oxide and aluminum oxide.

Further, the oxide insulating layer formed by the sol-gel method in the second invention can be the same as the oxide insulating layer in the first invention, for example, containing ceramic particles or the like. It can be formed from liquid precursors of metal oxides.

Also in this second invention, like the first invention, it is preferable to use copper or a copper alloy as the base material. Further, the thickness of the oxide insulating layer is preferably 1/2 or more of the diameter or thickness of the base material.

[Operations and Effects of the Invention] In the first invention of this application, on the outer layer surface of the group H, Ti,
At least one selected from the group consisting of Nb and Ta
A metal layer containing different types of metals is formed. Ti, Nb
, and Ta have a melting point of 151[deg.]C or higher, and do not melt even if the temperature exceeds 100[][deg.]C], which is the temperature at which conventional Cu conductors melt. Therefore, the inorganic insulated conductor of the first invention in which the base material is covered with a metal layer containing these metals exhibits excellent heat resistance.

Furthermore, Ti, Nb, and Ta have excellent workability and can be relatively easily processed into wire rods and the like. Furthermore, these metals also have excellent corrosion resistance, so they can be used as inorganic insulated conductors with excellent corrosion resistance.

By using a base material made of, for example, Cu, and providing a metal layer as described above around the base material, conductivity is increased and heat resistance is added! can be used. Further, as the base material, for example, a dispersion-strengthened alloy in which fine oxides such as aluminum oxide are dispersed in Cu or a Cu alloy can also be used. Using such a dispersion-strengthened alloy as a base material, 2τfti
This makes it possible to increase high-humidity strength and prevent recrystallization and oxidation caused by heating at high temperatures.

In the first aspect of the invention, it is preferable to form an oxide layer of the metal on the surface of the metal layer.
i is not particularly limited.

However, it is preferable to form a metal oxide layer by anodic oxidation because it is relatively easy and provides good adhesion. In other methods of forming metal oxide layers,
One example is a method of heating the outer surface of the metal layer in an oxidizing atmosphere.

By forming a metal oxide on the surface of the metal layer and forming an oxide insulating layer on the surface of the metal oxide layer, the metal oxide layer can be interposed between the metal layer and the oxide insulating layer. , the adhesion of the oxide insulating layer can be improved.

As described above, in the first invention, 1. An oxide containing at least one type of oxide selected from the group consisting of silicon oxide, zirconium oxide, and aluminum oxide can be used. All of these oxides are thermally stable and have good insulation properties at high temperatures. In particular, silicon oxide has a low dielectric constant and good high frequency characteristics. When forming a metal oxide layer on the surface of a metal layer, the above-mentioned silicon oxide, zirconium oxide, and aluminum oxide all have good adhesion with these metal oxides and can improve flexibility. I can do it.

The inorganic insulator according to the first invention has T I % N b
Since a metal layer containing at least one metal selected from the group consisting of S and Ta is provided on the outer peripheral surface of the base material, the inorganic insulated conductor is particularly excellent in heat resistance, nonflammability, and corrosion resistance. be able to. In particular, when a metal oxide layer is formed on the surface of the metal layer, the adhesion with the oxide insulating layer is good, and flexibility, compactness, and ease of handling are improved.

Further, since the outer surface of the oxide insulating layer can be formed flat, it can be an inorganic insulated conductor that is excellent in terms of non-emission of gas.

In the second invention of this application, on the outer surface of the base material, Ti,
, V, Y, , Z r, Nb, La, Hfs Ta.

A metal layer containing metals called valve metals such as WSAg and Sn is formed. The valve metal layer is a metal that improves the heat resistance of the conductor made of copper and allows easy application of an anodized film on its surface.Especially in terms of heat resistance, it is a metal that improves the heat resistance of the conductor made of copper. As in, Ti5Nb
, and Ta are excellent.

When a voltage is applied to the base material with this metal layer formed on its outer surface as an anode in an appropriate electrolytic solution, anodic oxidation is performed6. A strong semiconducting oxide film is formed on the outer surface. 1- of this anodic oxide film has an oxide insulating layer,
Adheres as a layer with good adhesion.

An insulating oxide layer is formed on the anodized layer by a sol-gel method, which is a solution method. A solution of a metal or semimetal compound and an alkoxide of L dissolved in an organic solvent, hydrolyzed, and dehydrated and condensed is applied onto the anodized layer. Further, the coating layer is heat-treated at a temperature higher than room temperature in order to volatilize the organic solvent and remove residual organic substances. Through this heat treatment, the oxide insulating layer formed by the sol-gel method is turned into a ceramic material. This heat treatment
It is preferable to carry out the process under an atmosphere of oxygen flow. The decomposition of the compound contained in the liquid applied onto the anodic oxide layer by the sol-gel method is completed at a temperature of about 500°C. However, when heat-treated at a temperature higher than that, the reaction between the metal constituting the anodic oxide layer and the metal or metalloid contained in the applied solution is promoted, causing the anodized layer and oxide to form. The adhesion between the insulating layer and the insulating layer is improved.

In this way, the ceramic oxide insulating layer exhibits excellent heat-resistant insulation even at high temperatures of 500° C. or higher. Further, the metal layer and the anodized layer have excellent adhesion to the conductor that constitutes the base material. Therefore, the adhesion between the oxide insulating layer and the outer surface of the base material is improved compared to the case where the oxide insulating layer is directly formed on the outer surface of the conductor by a sol-gel method. Therefore, the inorganic insulated conductor provided by this second invention has heat-resistant insulation and good flexibility.

Furthermore, the metal layer, anodized layer, and oxide insulating layer formed on the outer surface of the conductor have smooth outer surfaces. Therefore, it is possible to obtain a high dielectric breakdown voltage proportional to the film thickness, and to reduce the number of gas adsorption sources.

In this second invention, a metal layer and an anodized layer are formed between the base material and the oxide insulating layer. Therefore, through this anodized layer, combinations of base materials and inorganic insulating layers suitable for various uses can be selected.

Note that since a method using a solution is used to form the insulating layer, it is possible to coat a linear base material with simple equipment and at high speed.

Note that in the first invention and the second invention, the base material and the metal layer may be made of the same metal. In this case, there is no distinction between the base material and the metal layer, and one structure is the base material and the metal layer.

Example 1 A 1203 dispersion-strengthened steel alloy wire in which 3% of Al120 was dispersed in Cu by the internal oxidation method of Cu-AL gold alloy was used as a base material, a Nb vibe was fitted around the outer periphery of this base material, and the wire was drawn. A composite round wire conductor with a diameter of 2 mm was fabricated by processing. At this time N
The thickness of layer b was 0.1 mm. This conductor was anodized at 100V AC voltage in a 15% sulfuric acid solution, and N
An Nb oxide layer with a thickness of several μm was formed on the surface of the b layer.

8m01 of tetraethoxysilane was added on top of this Nb oxide layer.
%, water 32mo1% and ethyl alcohol 60mo1%
Heat and temper the solution containing
It was heat-treated and baked at 0°C. This coating and baking were repeated several times to form a silicon oxide layer with a thickness of 15 μm.

A cross-sectional view of the inorganic insulator obtained as described above is shown in FIG. Referring to FIG. 1, an Nb layer 2 as a metal layer is provided around the AQ 203 dispersion strengthened copper alloy wire 1, and an Nb oxide layer 3 is formed on the surface of the Nb layer 2. There is. A silicon oxide layer 4 is formed around the Nb oxide layer 3.

The insulating layer of this conductor was not damaged even at room temperature or even when heated up to 600° C., and it maintained excellent insulating properties.

Further, even when this conductor was wound around a core having a diameter of 20 mm, the insulation between the layers was maintained.

The apparent conductivity of this conductor is approximately 80% lAC3,
The diameter ratio of the pure conductor part is 98 to the outer diameter of the conductor after coating.
96, making it clear that a compact electric wire is sufficient to carry the necessary current.

Example 2 A Cu-0,15% Zr alloy plate was sandwiched between two Ti plates and composited by rolling to produce a flat plate conductor with a three-layer structure. The thickness of each part of the Ti layer, which is a metal layer, is 1 m.
m, the thickness of the base material Cu-0,15% Zr alloy part is 8 mm, and the apparent conductivity is about 70961 A
It was CS.

Both ends were sealed, and the surface of the Ti layer portion was anodized in a 5% sulfuric acid bath at a DC voltage of 150 V, and further heat treated in the air. The thickness of the formed Ti oxide layer was 7 μm.

Silicon butoxide 8+no1 on top of 20rl oxide layer
A solution was prepared by mixing 96 mica particles') wt in a solution of 90% and 7 kmol of aluminum, and this solution was coated on the T'l oxide surface layer. , /sheet, and then heated to form an oxide insulating layer with a thickness of about 20 um. ,.

Figure 2 shows the inorganic insulated conductor that has been stiffened (as described above).
15"ii 2. r L'?, rN't 't (
') T1 ■ 1 with both 11i1i1, f, gold m layer
2 is installed, and metal oxides Wi, J,: i, ... -C(',"r l
An oxide layer 13 is formed. J,',, n T
On top of the l oxide layer 13, AQ, , 0. Oxide layer 4 (silicon oxide layer with dispersed particles) 4 is set up as follows:
It is.

This inorganic insulated conductor is heated to 500°C.
rh'i, i in the radiation irradiation atmosphere: , l t-)
t) When a practical test was conducted for 7 hours, no deterioration of the insulation properties was observed.

Example 3 The surface of a Ta foil was oxidized (7, +1) by adding 5 mos of 1% alcohol solution of silicon butoxide to 2.1 ink of brake coat, and oxidized to a thickness of 3 μm by a dehydration-integrated reaction according to the popular Chushin Den. A physical insulating layer was formed.

The third cross-sectional view of this inorganic insulated conductor
With reference to FIG. 1-shown j0 and FIG. 3, soil 1j of Ta foil 2],
LJ T, a oxide layer'z: 27:I(:Q i
':' is exposed and 'Ia oxide layer 22 (,,:
A silicon oxide layer 2'3 is provided. ,,,Contents,
When the base material and the metal layer are the same, and the metal layer is the same,
.

The obtained l-inorganic insulating ring fne1δ has excellent heat resistance and flexibility, and is 0 as a thin-walled ib body for l-hinoki υ.Example 4 (a) Sub-processing pipe in electrolytic cell 1, 7 J people), 2 J 50,000 wire diameter 2
．． t,) Output silver/copper clad wire 蓓, ! , l L acid,
In an electrolytic solution with a volume ratio of water -], 1, the bath current is 100
Electrolytic polishing under the condition of A/dm2,, zl>, ffl
The outer layer of the silver/copper clad wire has a thickness of 11・Q.
The core material was copper with a 4 m silver layer.

(b) Preparation of coating solution used in the blue gel method Tetrabutyl ortho ricate, 1 water: isobrobyl alcohol - 8,32 □l) was mixed in a molar ratio of nitric acid to tetrabutyl ortho ricate. On the other hand, 10
It was added at a ratio of 3/0 mole.

Thereafter, this solution was heated and stirred at a temperature of 80° C. for 2 hours. As a result, a coating solution used in the sol-gel method was synthesized.

(c) Formation of anodic oxide film The wire rod subjected to quasi-FJil in (a) above was immersed in an electrolytic solution maintained at a temperature of 10°C. As the electrolytic solution, a solution of ammonium borate octahydrate:pure water-1 (mixed at a weight ratio of 1.34:89.66) was used.

After that, a positive voltage was applied to the wire, and the bath current was 1,09A/
The outer surface of the silver layer was anodized for 1 minute under drr+2 conditions. In this way, 1. An anodic oxide film with a thickness of about 0.5 μm was formed on the surface of the silver/copper clad wire. i'
The wire rod thus obtained was dried in an oxygen stream at a temperature of 100°C.

(d) Formation of oxide insulating layer) The wire rod obtained in step (C4) above is immersed in the coating solution of (b). B: L 71i wire rod,
The wire was heated for 10 minutes at a temperature of 400"C.Finally, the wire was heated for 10 minutes in an oxygen stream at .-50"C.

The insulated wire thus obtained is shown in FIG. 4. FIG. 4 is a diagram showing the lateral ttfr plane of the insulated wire according to the second invention. Referring to Figure 4,
A silver layer 41 was used as a white silver/copper clad 1 base material on the outer surface of the steel core wire 4. On the outer surface of this silver layer 41, a tripolar oxide film 42 was formed. A silicon oxide film 43 is formed on the anodic oxide film 42 by a sol-gel method.

Further, according to the fourth embodiment, the thickness of the insulating layer constituted by the anodic oxide film 42 and the silicon oxide film 43 is 15 mm.
It was about μm.

In order to evaluate the insulation properties of the obtained insulated wire, the dielectric breakdown voltage was determined as Δp1. Its dielectric breakdown voltage is 400V at room temperature, and 30V at 500℃.
It was 0■. In addition, on the outer peripheral surface of a cylinder with a diameter of 5 cm,
Even when this insulated wire was wound, no cracks occurred in the insulating layer.

Example 5 (a) Formation of Ti thin film A Ti thin film with a thickness of 2 μm was formed on the outer surface of a copper wire with a wire diameter of 2 mm using the RF magnetron sputtering method. The sputtering conditions at this time are traveling waves of 4
00W, Ar gas pressure 1 x 10'-2 torr, number of rotations of the wire 1 time/sec, parallel movement speed of the wire with the target 1c
m/min.

(b) Preparation of coating solution used in sol-gel method A solution of tributoxyaluminum: triethanolamine: water: isobutylene alcohol-5 mixed at a molar ratio of 10:5:80 was heated at 50°C for 1 hour. The mixture was heated and stirred.

As a result, a coating solution used in the sol-gel method was synthesized.

(c) Formation of anodic oxidation solution The wire rod obtained in the above (a) was immersed in an electrolytic solution maintained at a temperature of 10°C. As the electrolytic solution, a solution of ammonium borate octahydrate and pure water mixed in a weight ratio of 10°34:89.66 was used. After that, a positive voltage was applied to the wire, and the bath current was 0.01A/1m2.
The outer surface of the Ti layer was anodized for 0 minutes. In this way, an anodic oxide film with a thickness of about 1 μm was formed on the surface of the wire. The obtained wire rod was dried in an oxygen stream at a temperature of 200°C.

(d) Formation of oxide insulating layer The wire rod obtained in (C) above was immersed in the coating solution of (b). The wire rod whose outer surface was coated with the coating solution in this way was heated 10 times at a temperature of 400° C. for 10 minutes.

Finally, this wire was heated for 10 minutes in an oxygen stream at a temperature of 500°C.

The dielectric breakdown voltage obtained as described above is shown in FIG. FIG. 5 is a sectional view showing a cross section of an insulated wire according to the second invention. Referring to FIG. 5, the copper wire 5
A Ti film 51 is formed on the outer surface of 0. This Ti
Anodized M52 is formed on the outer surface of membrane 51.

Aluminum oxide [53] is formed on this anodic oxide film 52 by a sol-gel method. Further, according to the fifth embodiment, the anodic oxide film 52 and the aluminum oxide film 53
The thickness of the insulating layer composed of the above was about 40 μm.

In order to evaluate the insulation properties of the obtained insulated wire, the dielectric breakdown voltage was determined as dP1. At room temperature, its dielectric breakdown voltage is 1. OkV, 8 at a temperature of 500℃
It was 00v. Further, even when this insulated wire was wound around the outer peripheral surface of a cylinder having a diameter of 2 cm, no cracks were generated in the insulating layer.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the first invention of this application. Figure 2 shows the second invention of the first invention of this application.
It is a perspective view showing an example of this. FIG. 3 is a sectional view showing a third embodiment of the first invention of this application. FIG. 4 is a sectional view showing the first embodiment of the second invention of this application. FIG. 5 is a sectional view showing a second embodiment of the second invention of this application. In the figure, 1 is ALoa/)) shot copper alloy wire, 2 is Nb layer, 3 is Nb oxide layer, 4 is silicon oxide layer, 11 is C
u-0,15%Z "alloy plate, 12 is Ti layer, 13 is Ti
oxide layer, 14 is a silicon oxide layer, 21 is Ta foil, 22 is T
a oxide layer, 23 a silicon oxide layer, 40 a Cu core wire, 41
is an Ag layer, 42 and 52 are anodic oxide films, 43 is a silicon oxide film, 5o is a Cu wire, 51 is a Ti film, and 53 is an aluminum oxide film. 1st Figure 1: 2: 3 pa 4: A 203 Now is a good time 648. Rei Zen Hyo Nb Man Rui Hungry Law JL Prefecture Man Figure 2/l: C, -0, Hzui Z and 8 way 14: Atsushi I ζ
Jt early man/2; r; A/3. Figure 3 Yu 1: To T 4 22-cho 1-4 23: Hairy Cmet! 1 kidney

Claims (13)

[Claims] (1) A base material having an outer surface and containing an electrical conductor;
An inorganic insulated conductor comprising: a metal layer containing at least one metal selected from the group consisting of; and an oxide insulating layer provided around the metal layer. (2) forming an oxide layer of the metal on the surface of the metal layer, and forming the oxide insulating layer on the metal oxide layer;
The inorganic insulated conductor according to claim 1. (3) The inorganic insulated conductor according to claim 2, wherein the metal oxide layer is formed by anodizing the surface of the metal layer. (4) The inorganic insulated conductor according to claim 1, wherein the oxide insulating layer contains at least one type of oxide selected from the group consisting of silicon oxide, zirconium oxide, and aluminum oxide. (5) the oxide insulating layer is formed by applying a liquid precursor of a metal oxide and heat-treating it;
The inorganic insulated conductor according to claim 1. (6) The inorganic insulated conductor according to claim 5, wherein the liquid precursor of the metal oxide is prepared from a metal alkoxide or a metal carboxylic acid ester. (7) The inorganic insulated conductor according to claim 5, wherein the liquid metal oxide precursor contains ceramic particles. (8) The inorganic insulated conductor according to claim 1, wherein the base material contains an alloy mainly composed of Cu as an electrical conductor, and has oxide particles such as aluminum oxide dispersed therein. (9) The inorganic insulated conductor according to claim 8, wherein the copper alloy contains at least 2% by weight or less of at least one element selected from the group consisting of Cu, Zr, and Fe. (10) The inorganic insulated conductor according to claim 1, wherein the thickness of the oxide insulating layer is 1/2 or less of the diameter or thickness of the base material. (11) a base material having an outer surface and containing an electrical conductor, formed on the outer surface of the base material, containing Ti, V, Y, Zr,
a metal layer containing at least one metal selected from the group consisting of Nb, La, Hf, Ta, W, Ag, and Sn; an anodic oxide layer formed on the metal layer; and an anodic oxide layer on the anodic oxide layer. and an oxide insulating layer formed by a sol-gel method. (12) The inorganic insulated conductor according to claim 11, wherein the oxide insulating layer contains at least one oxide selected from the group consisting of silicon oxide, zirconium oxide, and aluminum oxide. (13) The inorganic insulated conductor according to claim 11, wherein the base material includes copper or a copper alloy.