CA2029868C - Insulated wire - Google Patents
Insulated wireInfo
- Publication number
- CA2029868C CA2029868C CA002029868A CA2029868A CA2029868C CA 2029868 C CA2029868 C CA 2029868C CA 002029868 A CA002029868 A CA 002029868A CA 2029868 A CA2029868 A CA 2029868A CA 2029868 C CA2029868 C CA 2029868C
- Authority
- CA
- Canada
- Prior art keywords
- layer
- oxide
- insulated wire
- chromium oxide
- wire
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/17—Protection against damage caused by external factors, e.g. sheaths or armouring
- H01B7/29—Protection against damage caused by extremes of temperature or by flame
- H01B7/292—Protection against damage caused by extremes of temperature or by flame using material resistant to heat
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/02—Disposition of insulation
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B13/00—Apparatus or processes specially adapted for manufacturing conductors or cables
- H01B13/06—Insulating conductors or cables
- H01B13/065—Insulating conductors with lacquers or enamels
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
- H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
- H01B3/10—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances metallic oxides
- H01B3/105—Wires with oxides
Abstract
An insulated wire is suitable for a distribution wire, a wire for winding or the like, which is employed under high-vacuum environment or high-temperature environment such as a high vacuum apparatus or a high temperature service apparatus. This insulated wire comprises a base material (1), a chromium oxide containing layer (2), and an oxide insulating layer (3). The base material (1) includes a conductor. The chromium oxide containing layer (2) is formed on an outer surface of the base material (1). The oxide insulating layer (3) is formed by applying a precursor solution of a metallic oxide onto the chromium oxide containing layer (2) by a sol-gel method or an organic acid salt pyrolytic method.
This insulated wire exhibits heat resistance/insulability as well as excellent flexibility, and provides no gas adsorption source.
This insulated wire exhibits heat resistance/insulability as well as excellent flexibility, and provides no gas adsorption source.
Description
SPECIFICATION
Title of the Invention Insulated Wire Field of the Invention The present invention relates to an insulated wire, - and more particularly, it relates to an insulated wire such as a distribution wire, a wire for winding or the like which is employed under high-vacuum environment or high-temperature environment such as a high-vacuum apparatus or a high-temperature service apparatus.
Background of the Invention An insulated wire may be applied to equipment such as heating equipment or a fire alarm, for which safety under - a high temperature is required. Further, the insulated wire is also used under environment in an automobile, which is heated to a high temperature. An insulated wire formed by a conductor which is coated with heat resistant organic resin such as polyimide, fluorocarbon resin or the like has generally been used as such an insulated wire.
As to application for which high heat resistance is required, or employment under environment for which a high degree of vacuum is required, organic coating is insufficient in view of heat resistance, no gas emission property and the like. Thus, an insulated wire of such a form that a conductor is inserted in an insulator tube of - 1- ~
ceramics, an MI cable (Mineral Insulated cable) of such a form that a conductor is inserted in a heat resistant alloy tube of a stainless steel alloy etc. which is filled with metal oxide powder of magnesium oxide etc., or the like has been employed for such application.
A fiber-glass braided insulated wire employing textile glass fiber as an insulating member etc. is listed as an insulated wire for which flexibility is required with heat resistance.
~ 10 In the aforementioned insulated wire coated with organic resin having heat resistance, the highest temperature at which insulability can be maintained is about 200C at the most. Therefore, it has been impossible to employ such an organic insulated coated wire for application for which guarantee for insulability is required under a high temperature of at least 200C.
Further, the insulated wire which is improved in heat resistance through an insulator tube of ceramics has disadvantages such as inferior flexibility. The MI cable -20 is formed by a heat resistant alloy tube and a conductor, and hence the outer diameter of the cable is increased - with respect to the conductor radius. Thus, the MI cable has a relatively large section with respect to electric energy allowed by the conductor which is passed through the heat resistant alloy tube. In order to use the MI
20~9868 cable as a wire for winding which is wound on a bobbin etc. in the form of a coil, however, it is necessary to bend the heat resistant alloy tube in prescribed curvature. In this case, bending performed on the heat resistant alloy tube involves difficulty. When the MI
cable is wound in the form of a coil, further, it is difficult to improve space factor since the tube of its outer layer is thick as compared with the conductor.
Further, when the fiber-glass braided insulated wire ., .
having heat resistance is employed and worked into a prescribed configuration in response to its application, the network of the braid is disturbed to cause a -:- breakdown. In addition, dust of glass is generated from -~ the glass fiber. This glass dust may serve as a gas adsorption source. Therefore, when the fiber-glass - braided insulated wire is used under environment for which a high degree of vacuum is required, it has been impossible to maintain a high degree of vacuum due to the gas adsorption source provided by the glass dust.
On the other hand, there has generally been the so-called alumite wire prepared by performing anodic oxidation treatment on a wire of aluminum or an aluminum ~- - alloy, as an insulated wire which is excellent in heat resistance, insulability and heat dissipativity. In this alumite wire, its base material is restricted to aluminum.
~urther, an inorganic insulating layer formed on the base material is also restricted to aluminum oxide. Thus, there has been such a problem that it is impossible to select combinations of the base material and the inorganic insulating layer which are suitable for various uses.
Disclosure of the Invention Accordingly, the present invention has been proposed in order to solve the aforementioned problems, and its object is to provide an insulated wire comprising the ~ 10 following items:
(a) It has high insulability under environment of a high temperature.
(b) It is excellent in flexibility.
(c) It comprises no gas adsorption source.
(d) Combinations of a base material and an inorganic insulating layer suitable for various uses can be selected.
An insulated wire according to the present invention comprises a base material, a chromium oxide contA;ning layer, and an oxide insulating layer. The base material has an outer surface, and includes a conductor. The ~ chromium oxide cont~;n;ng layer is formed on the outer -`! surface of the base material. The oxide insulating layer is formed by applying a precursor solution of a metallic oxide onto the chromium oxide containing layer by a sol-~_ 2029868 gel method or an organic acid salt pyrolytic method.
The chromium oxide cont~ining layer is preferablyformed by an electrochemical technique. The electrochemical technique includes electrolytic plating or S electroless plating. The underlayer to be provided with the oxide insulating layer may be a CrO3x (1.5 < X < 2.5) layer, in order to preferably serve as an adhesion layer.
Namely, the layer formed by the electrochemical technique has a chromium oxide layer as its outermost layer. The .
oxide insulating layer preferably contains silicon oxide, aluminum oxide or zirconium oxide. As to the base material, copper or a copper alloy is ~referably employed in view of high conductivity and the cost. In consideration of a use at a higher temperature or the like, nickel chromium, silver, iron or a ferroalloy, a stainless steel alloy, or titanium or a titanium alloy is preferably contained in the surface layer of the base material.
It is known that a chrome plated layer is formed on a conductor of copper or a copper alloy etc. as an excellent adhesion layer. However, insulating oxide ceramics such as silicon oxide obtained by heat treatment of a precursor solution of a metallic oxide hardly exhibits adhesion with respect to the chrome plated layer. This is based on recognition of the inventors.
In an insulated wire obtained by directly forming a thin film of ceramics on a surface of a conductor made of copper, further, the ceramics thin film serving as an insulating layer has insufficient adhesion with respect to a base material.
According to the present invention, therefore, a layer having a chromium oxide layer as its outermost layer is formed on an outer surface of a base material.
Insulating oxide ceramics adheres onto the chromium oxide layer as a layer having excellent adhesion.
The aforementioned chromium oxide layer is formed by an electrochemical technique. When the chromium oxide layer is formed by electrolytic plating, a substance - obtained by adding a small amount of organic acid to an aqueous solution of chromic anhydride is used as an electrolyte. Although a sergeant bath mainly composed of chromic anhydride or sulfuric acid is known as an electrolytic bath employed for chrome plating, it is different from this bath in the following point: Namely, mineral acid mixed into the electrolytic bath has a function of dissolving chromic anhydride which is generated on the surface of a plated layer in electrolytic plating. Therefore, a glossy metallic chrome layer is plated when a sergeant bath is employed. In the present invention, it is necessary to preferentially plate 2029~68 chromium oxide. Therefore, a small amount of organic acid is added to an electrolytic bath employed in the present invention. In a case of using mineral acid such as sulfuric acid, further, it is necessary to employ a particularly diluté electrolytic bath. Namely, chromic anhydride concentration is not more than 50 g/Q and sulfuric acid concentration is not more than 1 g/Q.
Further, while a thin film of insulating ceramics is formed on the outer surface of a layer mainly composed of chromium oxide by heat treatment of a precursor solution of a metallic oxide, the layer mainly composed of chromium oxide preferably has a roughened surface, in order to further increase adhesion of the thin film.
The chromium oxide containing layer may be formed by electrolytic plating employing an electrolyte which is prepared by adding sodium citrate, sodium carbonate or the like, for example, to an aqueous solution of sodium chromate. In this case, the as-formed layer is mainly composed of chromium oxide, which is generated by trivalent reduction of hexavalent chromium contained in the electrolyte. If copper is used as a base material in this electrolytic plating treatment, the base material surface is oxidized and the chromium oxide contA;~;ng layer is formed in the exterior thereof. However, adhesion of the chromium oxide cont~; n; ng layer with respect to the base material is not reduced by such oxidation of the base material surface.
Conditions for electrolytic plating for forming the inventive chromium oxide containing layer are different from those for general bright plating in treatment current d`ensity etc. Although the current density is set at 10 to 60 A/dm2 in the bright plating, depending on the treatment temperature, the current density is set at 100 to 200 A/dm2 in the present invention. A chromium oxide con~;n;~g layer having a roughened surface can be formed by this condition of the current density.
On the chromium oxide containing layer, an insulating oxide layer is formed by application of a precursor solution of a metallic oxide. The precursor solution of a metallic oxide mentioned in this specification is a ~~ solution prepared from a metal organic compound, which isbroadly classified in correspondence to a sol-gel method or an organic acid salt pyrolytic method, and those of the following two types are included:
The first type of precursor solution is a solution which is generated by making hydrolytic reaction and dehydration/condensation reaction of a compound cont~;n;~g hydrolyzable metal-oxygen-organic group bonds such as metal alkoxide or acetate of a metal. This solution may contain an organic solvent such as alcoholj a raw material .
compound such as metal alkoxide, and water and a catalyst required for hydrolytic reaction. Further, it generally contains an organic residual group such as alkoxide, dissimilarly to hydroxide sol that is generated from inorganic salt.
The second type of precursor solution is a solution prepared by dissolving a metal organic compound such as organic acid salt of a metal in an appropriate organic solvent. In a method employing this type of precursor solution, a metallic oxide is generated by pyrolyzation through heating after application. Therefore, a decomposition temperature of the employed metal organic - compound must be lower than its boiling point or ~ sublimation point.
The metal organic compound mentioned in this specification is a concept similar to "metal-organic compounds" described in Journal of Materials Science 12 (1977) pp. 1203 to 1208, for example.
Further, the applied layer must be left at a temperature higher than the room temperature, for volatilization of the organic solvent and removal of a residual organic substance. However, the temperature of the atmosphere for such leaving must not be higher than the melting point of the metal forming the base material.
It is possible to form almost all metallic oxide--based ceramics covering by application of a precursor solution of a metallic oxide. SiO2, Al2O3, ZrO4, TiO2, MgO
or the like can be listed as an example of a metallic oxide formed by this method. Further, ethoxide, propoxide, butoxide or the like can be listed as metal alkoxide employed for the first type of precursor solution. Metallic salt such as naphtanic acid, caprylic acid, stearic acid, octylic acid or the like is preferable as organic salt employed for the second type of precursor solution.
The oxide insulating layer formed from the precursor solution of the metallic oxide by the sol-gel method or the organic acid salt pyrolytic method is an oxide which is completely converted to a metallic oxide. This oxide - 15 is preferably formed by heat treatment under an atmosphere in an oxygen current. In general, decomposition of the compound contained in the solution which is applied onto the chromium oxide cont~ini ng layer is completely terminated at a temperature of about 500C. If the same is heat treated at a higher temperature, however, reaction - between elements forming the chromium oxide cont~i n i ng layer and a metal or semimetal contained in the applied ,~
solution is facilitated, whereby adhesion between the chromium oxide cont~i n i ng layer and the oxide layer is improved.
Thus, the oxide insulating layer converted to ceramics exhibits excellent heat resistance/insulability also under a high temperature of at least 500C. Further, the chromium oxide containing layer is excellent in adhesion to the conductor forming the base material.
Therefore, adhesion between the oxide insulating layer and the outer surface of the base material is improved as compared with the case of directly forming the oxide insulating layer on the outer surface of the conductor by heat treatment of the precursor solution of the metallic oxide. Thus, the insulated wire provided according to the present invention has heat resistance/Lnsulability, as - well as excellent flexibility.
Further, the oxide insulating layer formed on the chromium oxide contAin;ng layer has a smooth outer surface. Therefore, a high breakdown voltage proportionate to the film thickness can be obtained, while it is possible to reduce a gas adsorption source.
According to the present invention, in addition, the chromium oxide contA;ning layer is formed between the base material and the oxide insulating layer. Therefore, combinations with the inorganic insulating layer suitable for various uses can be selected through the chromium oxide containing layer.
Brief Description of the Drawings 20298fi8 Fig. 1 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 1.
Fig. 2 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 2.
: Fig. 3 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 3.
., Fig. 4 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 4.
Fig. 5 is a graph showing the result of measurement of surface roughness of a chromium oxide cont~in;ng layer formed in accordance with Example 3 or Example 4.
Fig. 6 is a graph showing the result of measurement of surface roughness of a chrome plated layer formed in accordance with Reference Example.
Best Modes of Carrying Out the Invention ExamPle 1 - (a) Formation of Chromium Oxide Cont~;ning Layer Electrolytic plating treatment was performed on an outer surface of a copper wire of 2 mm~ in wire diameter.
At this time, an electrolyte was prepared from that having concentration of 40 g/Q of chromic anhydride and 0.45 g/Q
of sulfuric acid. As to plating conditions, the bath temperature was 50C, the current density was 140 A/dm2, and the treatment time was two minutes. Thus~ a chromium oxide cont~;n;ng layer was formed on the outer surface of the copper wire with a film thickness of about 1 ~m.
(b) Preparation of Coating Solution used for Sol-Gel - Method Nitric acid was added to a solution mixed in mole ratios of tetrabutyl orthosilicate:water:isopropyl alcohol = 8:32:60 in a ratio of 3/100 mole with respect to tetrabutyl orthosilicate. Thereafter this solution was heated/stirred at a temperature of 80C for two hours.
Thus, a coating solution used for a sol-gel method was synthesized.
(c) Coating ' The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 400C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution. Finally, this wire was heated in an oxygen current of 500C in temperature for 10 minutes.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 1. Fig. 1 is a sectional view showing a cross section of the insulated wire obtained according to Example 1. Referring to Fig.
1, a chromium oxide containing layer 2 is formed on an outer surface of a copper wire 1. On this chromium oxide .
contAining layer 2, a silicon oxide layer 3 is formed by the sol-gel method as an oxide insulating layer. The film - thickness of an insulating layer formed by the chromium oxide contAining layer 2 and the silicon oxide layer 3 was about 4.0 ~m.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its breakdown voltage was 800 V under the room temperature, and was 600 V under a temperature of 800C. Even if this insulated wire was wound on an outer pe~ipheral surface of a cylinder having a diameter of 10 cm, no cracking was caused in the insulating layer.
ExamPle 2 (a) Formation of Chromium Oxide ContAining Layer A copper wire of 2 mm~ in wire diameter was vapor-degreased through use of perchloroethylene. Thereafter the copper wire was dipped in a solution mixed in volume ratios of 85 % phosphoric acid:70 % nitric acid:water =
15:2:3, thereby roughening its surface.
Then, the copper wire was used as a cathode and a stainless steel plate was used as an anode to perform electrolytic plating treatment by feeding a direct current of 0.05 A/dm2. At this time, a solution of about 1 Q
prepared by dissolving 30 g of sodium chromate, 30 g of sodium citrate and 30 g of sodium carbonate in water respectively was used as an electrolyte.
Thus, a copper oxide layer having a film thickness of about 1 ~m was formed on the outer surface of the copper - wire, and a chromium oxide containing layer was formed in its exterior with a film thickness of about 0.1 ~m.
(b) Preparation of Coating Solution used for Sol-Gel Method A solution mixed in mole ratios of tetrabutyl orthozirconate [(C4H9O)4Zr]:water:n-butyl alcohol = 5:15:80 was heated/stirred at a temperature of~120C for two hours. Thus, a coating solution used for a sol-gel method was synthesized.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 400C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 2. Fig. 2 is a sectional view showing a cross section of the insulated wire obtained according to Example 2. Referring to Eig.
Title of the Invention Insulated Wire Field of the Invention The present invention relates to an insulated wire, - and more particularly, it relates to an insulated wire such as a distribution wire, a wire for winding or the like which is employed under high-vacuum environment or high-temperature environment such as a high-vacuum apparatus or a high-temperature service apparatus.
Background of the Invention An insulated wire may be applied to equipment such as heating equipment or a fire alarm, for which safety under - a high temperature is required. Further, the insulated wire is also used under environment in an automobile, which is heated to a high temperature. An insulated wire formed by a conductor which is coated with heat resistant organic resin such as polyimide, fluorocarbon resin or the like has generally been used as such an insulated wire.
As to application for which high heat resistance is required, or employment under environment for which a high degree of vacuum is required, organic coating is insufficient in view of heat resistance, no gas emission property and the like. Thus, an insulated wire of such a form that a conductor is inserted in an insulator tube of - 1- ~
ceramics, an MI cable (Mineral Insulated cable) of such a form that a conductor is inserted in a heat resistant alloy tube of a stainless steel alloy etc. which is filled with metal oxide powder of magnesium oxide etc., or the like has been employed for such application.
A fiber-glass braided insulated wire employing textile glass fiber as an insulating member etc. is listed as an insulated wire for which flexibility is required with heat resistance.
~ 10 In the aforementioned insulated wire coated with organic resin having heat resistance, the highest temperature at which insulability can be maintained is about 200C at the most. Therefore, it has been impossible to employ such an organic insulated coated wire for application for which guarantee for insulability is required under a high temperature of at least 200C.
Further, the insulated wire which is improved in heat resistance through an insulator tube of ceramics has disadvantages such as inferior flexibility. The MI cable -20 is formed by a heat resistant alloy tube and a conductor, and hence the outer diameter of the cable is increased - with respect to the conductor radius. Thus, the MI cable has a relatively large section with respect to electric energy allowed by the conductor which is passed through the heat resistant alloy tube. In order to use the MI
20~9868 cable as a wire for winding which is wound on a bobbin etc. in the form of a coil, however, it is necessary to bend the heat resistant alloy tube in prescribed curvature. In this case, bending performed on the heat resistant alloy tube involves difficulty. When the MI
cable is wound in the form of a coil, further, it is difficult to improve space factor since the tube of its outer layer is thick as compared with the conductor.
Further, when the fiber-glass braided insulated wire ., .
having heat resistance is employed and worked into a prescribed configuration in response to its application, the network of the braid is disturbed to cause a -:- breakdown. In addition, dust of glass is generated from -~ the glass fiber. This glass dust may serve as a gas adsorption source. Therefore, when the fiber-glass - braided insulated wire is used under environment for which a high degree of vacuum is required, it has been impossible to maintain a high degree of vacuum due to the gas adsorption source provided by the glass dust.
On the other hand, there has generally been the so-called alumite wire prepared by performing anodic oxidation treatment on a wire of aluminum or an aluminum ~- - alloy, as an insulated wire which is excellent in heat resistance, insulability and heat dissipativity. In this alumite wire, its base material is restricted to aluminum.
~urther, an inorganic insulating layer formed on the base material is also restricted to aluminum oxide. Thus, there has been such a problem that it is impossible to select combinations of the base material and the inorganic insulating layer which are suitable for various uses.
Disclosure of the Invention Accordingly, the present invention has been proposed in order to solve the aforementioned problems, and its object is to provide an insulated wire comprising the ~ 10 following items:
(a) It has high insulability under environment of a high temperature.
(b) It is excellent in flexibility.
(c) It comprises no gas adsorption source.
(d) Combinations of a base material and an inorganic insulating layer suitable for various uses can be selected.
An insulated wire according to the present invention comprises a base material, a chromium oxide contA;ning layer, and an oxide insulating layer. The base material has an outer surface, and includes a conductor. The ~ chromium oxide cont~;n;ng layer is formed on the outer -`! surface of the base material. The oxide insulating layer is formed by applying a precursor solution of a metallic oxide onto the chromium oxide containing layer by a sol-~_ 2029868 gel method or an organic acid salt pyrolytic method.
The chromium oxide cont~ining layer is preferablyformed by an electrochemical technique. The electrochemical technique includes electrolytic plating or S electroless plating. The underlayer to be provided with the oxide insulating layer may be a CrO3x (1.5 < X < 2.5) layer, in order to preferably serve as an adhesion layer.
Namely, the layer formed by the electrochemical technique has a chromium oxide layer as its outermost layer. The .
oxide insulating layer preferably contains silicon oxide, aluminum oxide or zirconium oxide. As to the base material, copper or a copper alloy is ~referably employed in view of high conductivity and the cost. In consideration of a use at a higher temperature or the like, nickel chromium, silver, iron or a ferroalloy, a stainless steel alloy, or titanium or a titanium alloy is preferably contained in the surface layer of the base material.
It is known that a chrome plated layer is formed on a conductor of copper or a copper alloy etc. as an excellent adhesion layer. However, insulating oxide ceramics such as silicon oxide obtained by heat treatment of a precursor solution of a metallic oxide hardly exhibits adhesion with respect to the chrome plated layer. This is based on recognition of the inventors.
In an insulated wire obtained by directly forming a thin film of ceramics on a surface of a conductor made of copper, further, the ceramics thin film serving as an insulating layer has insufficient adhesion with respect to a base material.
According to the present invention, therefore, a layer having a chromium oxide layer as its outermost layer is formed on an outer surface of a base material.
Insulating oxide ceramics adheres onto the chromium oxide layer as a layer having excellent adhesion.
The aforementioned chromium oxide layer is formed by an electrochemical technique. When the chromium oxide layer is formed by electrolytic plating, a substance - obtained by adding a small amount of organic acid to an aqueous solution of chromic anhydride is used as an electrolyte. Although a sergeant bath mainly composed of chromic anhydride or sulfuric acid is known as an electrolytic bath employed for chrome plating, it is different from this bath in the following point: Namely, mineral acid mixed into the electrolytic bath has a function of dissolving chromic anhydride which is generated on the surface of a plated layer in electrolytic plating. Therefore, a glossy metallic chrome layer is plated when a sergeant bath is employed. In the present invention, it is necessary to preferentially plate 2029~68 chromium oxide. Therefore, a small amount of organic acid is added to an electrolytic bath employed in the present invention. In a case of using mineral acid such as sulfuric acid, further, it is necessary to employ a particularly diluté electrolytic bath. Namely, chromic anhydride concentration is not more than 50 g/Q and sulfuric acid concentration is not more than 1 g/Q.
Further, while a thin film of insulating ceramics is formed on the outer surface of a layer mainly composed of chromium oxide by heat treatment of a precursor solution of a metallic oxide, the layer mainly composed of chromium oxide preferably has a roughened surface, in order to further increase adhesion of the thin film.
The chromium oxide containing layer may be formed by electrolytic plating employing an electrolyte which is prepared by adding sodium citrate, sodium carbonate or the like, for example, to an aqueous solution of sodium chromate. In this case, the as-formed layer is mainly composed of chromium oxide, which is generated by trivalent reduction of hexavalent chromium contained in the electrolyte. If copper is used as a base material in this electrolytic plating treatment, the base material surface is oxidized and the chromium oxide contA;~;ng layer is formed in the exterior thereof. However, adhesion of the chromium oxide cont~; n; ng layer with respect to the base material is not reduced by such oxidation of the base material surface.
Conditions for electrolytic plating for forming the inventive chromium oxide containing layer are different from those for general bright plating in treatment current d`ensity etc. Although the current density is set at 10 to 60 A/dm2 in the bright plating, depending on the treatment temperature, the current density is set at 100 to 200 A/dm2 in the present invention. A chromium oxide con~;n;~g layer having a roughened surface can be formed by this condition of the current density.
On the chromium oxide containing layer, an insulating oxide layer is formed by application of a precursor solution of a metallic oxide. The precursor solution of a metallic oxide mentioned in this specification is a ~~ solution prepared from a metal organic compound, which isbroadly classified in correspondence to a sol-gel method or an organic acid salt pyrolytic method, and those of the following two types are included:
The first type of precursor solution is a solution which is generated by making hydrolytic reaction and dehydration/condensation reaction of a compound cont~;n;~g hydrolyzable metal-oxygen-organic group bonds such as metal alkoxide or acetate of a metal. This solution may contain an organic solvent such as alcoholj a raw material .
compound such as metal alkoxide, and water and a catalyst required for hydrolytic reaction. Further, it generally contains an organic residual group such as alkoxide, dissimilarly to hydroxide sol that is generated from inorganic salt.
The second type of precursor solution is a solution prepared by dissolving a metal organic compound such as organic acid salt of a metal in an appropriate organic solvent. In a method employing this type of precursor solution, a metallic oxide is generated by pyrolyzation through heating after application. Therefore, a decomposition temperature of the employed metal organic - compound must be lower than its boiling point or ~ sublimation point.
The metal organic compound mentioned in this specification is a concept similar to "metal-organic compounds" described in Journal of Materials Science 12 (1977) pp. 1203 to 1208, for example.
Further, the applied layer must be left at a temperature higher than the room temperature, for volatilization of the organic solvent and removal of a residual organic substance. However, the temperature of the atmosphere for such leaving must not be higher than the melting point of the metal forming the base material.
It is possible to form almost all metallic oxide--based ceramics covering by application of a precursor solution of a metallic oxide. SiO2, Al2O3, ZrO4, TiO2, MgO
or the like can be listed as an example of a metallic oxide formed by this method. Further, ethoxide, propoxide, butoxide or the like can be listed as metal alkoxide employed for the first type of precursor solution. Metallic salt such as naphtanic acid, caprylic acid, stearic acid, octylic acid or the like is preferable as organic salt employed for the second type of precursor solution.
The oxide insulating layer formed from the precursor solution of the metallic oxide by the sol-gel method or the organic acid salt pyrolytic method is an oxide which is completely converted to a metallic oxide. This oxide - 15 is preferably formed by heat treatment under an atmosphere in an oxygen current. In general, decomposition of the compound contained in the solution which is applied onto the chromium oxide cont~ini ng layer is completely terminated at a temperature of about 500C. If the same is heat treated at a higher temperature, however, reaction - between elements forming the chromium oxide cont~i n i ng layer and a metal or semimetal contained in the applied ,~
solution is facilitated, whereby adhesion between the chromium oxide cont~i n i ng layer and the oxide layer is improved.
Thus, the oxide insulating layer converted to ceramics exhibits excellent heat resistance/insulability also under a high temperature of at least 500C. Further, the chromium oxide containing layer is excellent in adhesion to the conductor forming the base material.
Therefore, adhesion between the oxide insulating layer and the outer surface of the base material is improved as compared with the case of directly forming the oxide insulating layer on the outer surface of the conductor by heat treatment of the precursor solution of the metallic oxide. Thus, the insulated wire provided according to the present invention has heat resistance/Lnsulability, as - well as excellent flexibility.
Further, the oxide insulating layer formed on the chromium oxide contAin;ng layer has a smooth outer surface. Therefore, a high breakdown voltage proportionate to the film thickness can be obtained, while it is possible to reduce a gas adsorption source.
According to the present invention, in addition, the chromium oxide contA;ning layer is formed between the base material and the oxide insulating layer. Therefore, combinations with the inorganic insulating layer suitable for various uses can be selected through the chromium oxide containing layer.
Brief Description of the Drawings 20298fi8 Fig. 1 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 1.
Fig. 2 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 2.
: Fig. 3 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 3.
., Fig. 4 is a sectional view showing a cross section of an insulated wire according to the present invention in correspondence to Example 4.
Fig. 5 is a graph showing the result of measurement of surface roughness of a chromium oxide cont~in;ng layer formed in accordance with Example 3 or Example 4.
Fig. 6 is a graph showing the result of measurement of surface roughness of a chrome plated layer formed in accordance with Reference Example.
Best Modes of Carrying Out the Invention ExamPle 1 - (a) Formation of Chromium Oxide Cont~;ning Layer Electrolytic plating treatment was performed on an outer surface of a copper wire of 2 mm~ in wire diameter.
At this time, an electrolyte was prepared from that having concentration of 40 g/Q of chromic anhydride and 0.45 g/Q
of sulfuric acid. As to plating conditions, the bath temperature was 50C, the current density was 140 A/dm2, and the treatment time was two minutes. Thus~ a chromium oxide cont~;n;ng layer was formed on the outer surface of the copper wire with a film thickness of about 1 ~m.
(b) Preparation of Coating Solution used for Sol-Gel - Method Nitric acid was added to a solution mixed in mole ratios of tetrabutyl orthosilicate:water:isopropyl alcohol = 8:32:60 in a ratio of 3/100 mole with respect to tetrabutyl orthosilicate. Thereafter this solution was heated/stirred at a temperature of 80C for two hours.
Thus, a coating solution used for a sol-gel method was synthesized.
(c) Coating ' The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 400C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution. Finally, this wire was heated in an oxygen current of 500C in temperature for 10 minutes.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 1. Fig. 1 is a sectional view showing a cross section of the insulated wire obtained according to Example 1. Referring to Fig.
1, a chromium oxide containing layer 2 is formed on an outer surface of a copper wire 1. On this chromium oxide .
contAining layer 2, a silicon oxide layer 3 is formed by the sol-gel method as an oxide insulating layer. The film - thickness of an insulating layer formed by the chromium oxide contAining layer 2 and the silicon oxide layer 3 was about 4.0 ~m.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its breakdown voltage was 800 V under the room temperature, and was 600 V under a temperature of 800C. Even if this insulated wire was wound on an outer pe~ipheral surface of a cylinder having a diameter of 10 cm, no cracking was caused in the insulating layer.
ExamPle 2 (a) Formation of Chromium Oxide ContAining Layer A copper wire of 2 mm~ in wire diameter was vapor-degreased through use of perchloroethylene. Thereafter the copper wire was dipped in a solution mixed in volume ratios of 85 % phosphoric acid:70 % nitric acid:water =
15:2:3, thereby roughening its surface.
Then, the copper wire was used as a cathode and a stainless steel plate was used as an anode to perform electrolytic plating treatment by feeding a direct current of 0.05 A/dm2. At this time, a solution of about 1 Q
prepared by dissolving 30 g of sodium chromate, 30 g of sodium citrate and 30 g of sodium carbonate in water respectively was used as an electrolyte.
Thus, a copper oxide layer having a film thickness of about 1 ~m was formed on the outer surface of the copper - wire, and a chromium oxide containing layer was formed in its exterior with a film thickness of about 0.1 ~m.
(b) Preparation of Coating Solution used for Sol-Gel Method A solution mixed in mole ratios of tetrabutyl orthozirconate [(C4H9O)4Zr]:water:n-butyl alcohol = 5:15:80 was heated/stirred at a temperature of~120C for two hours. Thus, a coating solution used for a sol-gel method was synthesized.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 400C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 2. Fig. 2 is a sectional view showing a cross section of the insulated wire obtained according to Example 2. Referring to Eig.
2, a copper oxide layer 12 is formed on the outer surface of a copper wire 11. Further, a chromium oxide containing layer 13 is formed in the exterior of this copper oxide layer 12. On this chromium oxide cont~;n;ng layer 13, a -zirconium oxide layer 14 is formed by the sol-gel method as an oxide insulating layer. The film thickness of an insulating layer formed by the copper oxide layer 12, the chromium oxide cont~ining layer 13 and the zirconium oxide layer 14 was about 3.0 ~m.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its breakdown voltage was 700 V under the room temperature, and was 500 V under a temperature of 7~0C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 10 cm, no cracking was caused in the insulating layer.
Example 3 (a) Formation of Chromium Oxide Cont~;ning Layer Electrolytic plating treatment was performed on an outer surface of a nickel-plated copper wire of 1.8 mm~ in wire diameter. At this time, an electrolyte was prepared from that having concentration of 200 g/Q of chromic anhydride, 20 g/~ of ammonium methavanadate and 6.5 g/l of acetic acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 150 A/dm2, and the treatment time was two minutes. Thus, a chromium oxide cont~in;ng layer was formed on the outer surface of the nickel-plated copper wire with a film thickness of about 1 ~m.
As to the surface state of the chromium oxide cont~in;ng layer, the center line average roughness Ra was 0.15 ~m and the maximum height Ry was 0.87 ~m in accordance with Surface Roughness of IS0468-1982. The surface roughness was measured by using a surface contour measurer DERTAR3030 made by Sloan Inc., U.S.A., under conditions of a tracer diameter of 0.5 ~m, a stylus pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. The result of measurement is shown in Fig. 5.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method A coating solution was prepared by dissolving 20 g of 2-ethyl-hexanoic silicate in 100 mQ of dibutyl ether.
(c) The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 3. Fig. 3 is a sectional view showing a cross section of the insulated wire obtained according to Example 3. Referring to Fig.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its breakdown voltage was 700 V under the room temperature, and was 500 V under a temperature of 7~0C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 10 cm, no cracking was caused in the insulating layer.
Example 3 (a) Formation of Chromium Oxide Cont~;ning Layer Electrolytic plating treatment was performed on an outer surface of a nickel-plated copper wire of 1.8 mm~ in wire diameter. At this time, an electrolyte was prepared from that having concentration of 200 g/Q of chromic anhydride, 20 g/~ of ammonium methavanadate and 6.5 g/l of acetic acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 150 A/dm2, and the treatment time was two minutes. Thus, a chromium oxide cont~in;ng layer was formed on the outer surface of the nickel-plated copper wire with a film thickness of about 1 ~m.
As to the surface state of the chromium oxide cont~in;ng layer, the center line average roughness Ra was 0.15 ~m and the maximum height Ry was 0.87 ~m in accordance with Surface Roughness of IS0468-1982. The surface roughness was measured by using a surface contour measurer DERTAR3030 made by Sloan Inc., U.S.A., under conditions of a tracer diameter of 0.5 ~m, a stylus pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. The result of measurement is shown in Fig. 5.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method A coating solution was prepared by dissolving 20 g of 2-ethyl-hexanoic silicate in 100 mQ of dibutyl ether.
(c) The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 3. Fig. 3 is a sectional view showing a cross section of the insulated wire obtained according to Example 3. Referring to Fig.
3, a nickel-plated copper wire comprising a nickel-plated layer 22 formed on an outer surface of a copper wire 21 is used as a base material. A chromium oxide cont~ining layer 23 is formed on the outer surface of this nickel-plated copper wire. On the chromium oxide cont~i n i ng layer 23, a silicon oxide layer 24 is formed by an organic acid salt pyrolytic method as an oxide insulating layer.
The film thickness of an insulating layer formed by the chromium oxide cont~ining layer 23 and the silicon oxide layer 24 was about 5 ~m.
A breakdown voltage was measured i~n order to evaluate insulability of the obtained insulated wire. The breakdown voltage was 500 V under the room temperature, - 15 and was 300 V under a temperature of 800C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 5 cm, no cracking was caused in the insulating layer.
ExamPle 4 (a) Formation of Chromium Oxide Containing Layer - The so-called stainless steel clad copper wire of 1.8 mm~ in wire diameter, in which a stainless steel alloy (SUS304) was engaged on an outer surface of a copper wire, was used as a base material. Electrolytic plating treatment was performed on the outer surface of this stainless steel clad copper wire. At this time, an electrolyte was prepared from that having concentration of 200 g/Q of chromic anhydride, 20 g/Q of ammonium methavanadate and 6.5 giQ of acetic acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 150 A/dm2 and the treatment temperature was two minutes.
Thus, a chromium oxide contAining layer was formed on the outer surface of the stainless steel clad copper wire with a film thickness of about 1 ~m.
As to its surface state, the center line average roughness Ra was 0.15 ~m, and the mAxi~l-m height Ry was 0.87 ~m in accordance with Surface Roughness of IS0468-1982. The measurement was performed by using a surface contour measurer DEKTAK3030 made by Sloan Inc., U.S.A., - under conditions of a tracer diameter of 0.5 ~m, a stylus pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. As the result of this measurement, that shown in Fig. 5 was obtained similarly to Example 3.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method 25 g of aluminum tetra-i-butoxide was dissolved in 100 mQ of diethylene glycol monomethyl ether, and thereafter heated/stirred at 150C for one hour. This solution was stood to be cooled to the room temperature, and thereafter mixed with 3 g of alumina particles of 0.03 ~m in nominal particle size, thereby preparing a coating solution.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 4. Fig. 4 is a sectional view showing a cross section of the insulated wire obtained according to Example 4. Referring to Fig.
The film thickness of an insulating layer formed by the chromium oxide cont~ining layer 23 and the silicon oxide layer 24 was about 5 ~m.
A breakdown voltage was measured i~n order to evaluate insulability of the obtained insulated wire. The breakdown voltage was 500 V under the room temperature, - 15 and was 300 V under a temperature of 800C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 5 cm, no cracking was caused in the insulating layer.
ExamPle 4 (a) Formation of Chromium Oxide Containing Layer - The so-called stainless steel clad copper wire of 1.8 mm~ in wire diameter, in which a stainless steel alloy (SUS304) was engaged on an outer surface of a copper wire, was used as a base material. Electrolytic plating treatment was performed on the outer surface of this stainless steel clad copper wire. At this time, an electrolyte was prepared from that having concentration of 200 g/Q of chromic anhydride, 20 g/Q of ammonium methavanadate and 6.5 giQ of acetic acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 150 A/dm2 and the treatment temperature was two minutes.
Thus, a chromium oxide contAining layer was formed on the outer surface of the stainless steel clad copper wire with a film thickness of about 1 ~m.
As to its surface state, the center line average roughness Ra was 0.15 ~m, and the mAxi~l-m height Ry was 0.87 ~m in accordance with Surface Roughness of IS0468-1982. The measurement was performed by using a surface contour measurer DEKTAK3030 made by Sloan Inc., U.S.A., - under conditions of a tracer diameter of 0.5 ~m, a stylus pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. As the result of this measurement, that shown in Fig. 5 was obtained similarly to Example 3.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method 25 g of aluminum tetra-i-butoxide was dissolved in 100 mQ of diethylene glycol monomethyl ether, and thereafter heated/stirred at 150C for one hour. This solution was stood to be cooled to the room temperature, and thereafter mixed with 3 g of alumina particles of 0.03 ~m in nominal particle size, thereby preparing a coating solution.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed ten times on the wire whose outer surface was thus coated with the coating solution.
An insulated covered wire obtained in the aforementioned manner is shown in Fig. 4. Fig. 4 is a sectional view showing a cross section of the insulated wire obtained according to Example 4. Referring to Fig.
4, a stainless steel clad copper wire having a stainless steel alloy layer 32 on an outer surface of a copper wire 31 is used as a base material. A chromium oxide contA;ning layer 33 is formed on the outer surface of the stainless steel clad copper wire. On this chromium oxide contAining layer 33j an aluminum oxide layer 34 is formed by an organic acid salt pyrolytic method as an oxide insulating layer. This aluminum oxide layer 34 consists of an aluminum oxide mixed layer containing aluminum - particulates which have been mixed in the coating solution from the start. The film thickness of an insulating layer formed by the chromium oxide contAining layer 33 and the 202~868 aluminum oxide layer 34 was about 12 ~m.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its - breakdown voltage was 900 V under the room temperature, and was 700 V under a temperature of 800C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 15 cm, no cracking was caused in the insulating layer.
Reference Example (a) Formation of Metallic Chrome Plated Layer Electrolytic plating treatment was performed on an - outer surface of a nickel-plated coppe~ wire of 1.8 mm~ in wire diameter. At this time, an electrolyte to be used was prepared from that having concentration of 250 g/Q of chromic anhydride and 2.5 g/Q of sulfuric acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 40 A/dm2, and the treatment time was two minutes. Thus, a chrome contAining layer was formed on the outer surface of the nickel-plated copper wire with a film thickness of about 1 ~m.
As to its surface state, the center line average roughness Ra was 0.06 ~m and the m~ximllr height Ry was 0.51 ~m in accordance with Surface Roughness of ISO468-1982. The measurement was performed by using a surface contour measurer DEXTAK3030 made by Sloan Inc., U.S.A., under conditions of a tracer diameter of 0.5 ~m, a stylus ~ pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. The result of this measurement is shown in Fig. 6. A glossy metallic chrome layer was formed on the outer surface of the nickel-plated copper wire.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method A coating solution was prepared by dissolving 20 g of 2-ethyl-hexanoic silicate in 100 mQ of dibutyl ether.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed on the wire whose outer surface was thus coated with the coating solution, whereby the as-formed insulating layer was separated like a film after heating, and exhibited no adhesion.
Industrial Availability - 20 As hereinabove described, the insulated wire according to the present invention is suitable for a distribution wire, a wire for winding or the like, which is employed under high-vacuum environment or high-temperature environment such as a high vacuum apparatus or a high temperature service apparatus.
A breakdown voltage was measured in order to evaluate insulability of the obtained insulated wire. Its - breakdown voltage was 900 V under the room temperature, and was 700 V under a temperature of 800C. Even if this insulated wire was wound on an outer peripheral surface of a cylinder having a diameter of 15 cm, no cracking was caused in the insulating layer.
Reference Example (a) Formation of Metallic Chrome Plated Layer Electrolytic plating treatment was performed on an - outer surface of a nickel-plated coppe~ wire of 1.8 mm~ in wire diameter. At this time, an electrolyte to be used was prepared from that having concentration of 250 g/Q of chromic anhydride and 2.5 g/Q of sulfuric acid. As to plating conditions, the base material was used as a cathode, while the bath temperature was 50C, the current density was 40 A/dm2, and the treatment time was two minutes. Thus, a chrome contAining layer was formed on the outer surface of the nickel-plated copper wire with a film thickness of about 1 ~m.
As to its surface state, the center line average roughness Ra was 0.06 ~m and the m~ximllr height Ry was 0.51 ~m in accordance with Surface Roughness of ISO468-1982. The measurement was performed by using a surface contour measurer DEXTAK3030 made by Sloan Inc., U.S.A., under conditions of a tracer diameter of 0.5 ~m, a stylus ~ pressure of 10 mg, a reference length of 50 ~m, and no use of a cutoff filter. The result of this measurement is shown in Fig. 6. A glossy metallic chrome layer was formed on the outer surface of the nickel-plated copper wire.
(b) Preparation of Coating Solution used for Organic Acid Salt Pyrolytic Method A coating solution was prepared by dissolving 20 g of 2-ethyl-hexanoic silicate in 100 mQ of dibutyl ether.
(c) Coating The wire obtained by (a) was dipped in the coating solution of (b). A step of heating at a temperature of 500C for 10 minutes was performed on the wire whose outer surface was thus coated with the coating solution, whereby the as-formed insulating layer was separated like a film after heating, and exhibited no adhesion.
Industrial Availability - 20 As hereinabove described, the insulated wire according to the present invention is suitable for a distribution wire, a wire for winding or the like, which is employed under high-vacuum environment or high-temperature environment such as a high vacuum apparatus or a high temperature service apparatus.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An insulated wire comprising:
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-X (1.5 x 2.5) as the main component; and, an oxide insulating layer formed by applying a precursor solution of a metallic oxide onto the chromium oxide layer.
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-X (1.5 x 2.5) as the main component; and, an oxide insulating layer formed by applying a precursor solution of a metallic oxide onto the chromium oxide layer.
2. An insulated wire in accordance with claim 1, wherein said chromium oxide layer is formed by electrolytic plating.
3. An insulated wire in accordance with claim 1, wherein said oxide insulating layer contains at least one oxide member selected from the group consisting of silicon oxide, aluminum oxide and zirconium oxide.
4. An insulated wire in accordance with claim 1, wherein said substrate contains copper or a copper alloy.
5. An insulated wire in accordance with claim 4, wherein said surface layer of the substrate contains at least one member selected from the group consisting of nickel, chromium and stainless steel alloy.
6. An insulated wire in accordance with claim 1, wherein said oxide insulating layer contains ceramic particulates dispersed therein.
7. An insulated wire comprising:
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-x (1.5 x 2.5) as the main component; and, an oxide insulating layer formed on said chromium oxide layer by a sol-gel method.
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-x (1.5 x 2.5) as the main component; and, an oxide insulating layer formed on said chromium oxide layer by a sol-gel method.
8. An insulated wire comprising:
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-x (1.5 x 2.5) as the main component; and, an oxide insulating layer formed on said chromium oxide layer by an organic acid salt pyrolytic method.
a substrate having a core and a surface layer, at least the core being a conductor;
a chromium oxide layer formed on the substrate, such layer including CrO3-x (1.5 x 2.5) as the main component; and, an oxide insulating layer formed on said chromium oxide layer by an organic acid salt pyrolytic method.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7702889 | 1989-03-28 | ||
| JP1-77028 | 1989-03-28 | ||
| JP2-70843 | 1990-03-20 | ||
| JP2070843A JP2890631B2 (en) | 1989-03-28 | 1990-03-20 | Insulated wire |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2029868A1 CA2029868A1 (en) | 1990-09-29 |
| CA2029868C true CA2029868C (en) | 1996-09-24 |
Family
ID=26411968
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002029868A Expired - Fee Related CA2029868C (en) | 1989-03-28 | 1990-03-26 | Insulated wire |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0416131B1 (en) |
| JP (1) | JP2890631B2 (en) |
| KR (1) | KR940000845B1 (en) |
| AU (1) | AU627859B2 (en) |
| CA (1) | CA2029868C (en) |
| DE (1) | DE69013448T2 (en) |
| DK (1) | DK0416131T3 (en) |
| HK (1) | HK96795A (en) |
| WO (1) | WO1990011603A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2827333B2 (en) * | 1989-10-13 | 1998-11-25 | 住友電気工業株式会社 | Manufacturing method of heat-resistant insulating coil |
| EP0510258B1 (en) * | 1991-04-26 | 1995-06-14 | Sumitomo Electric Industries, Limited | Method of making an insulating member |
| DE69502270T2 (en) * | 1995-02-24 | 1999-01-07 | Sumitomo Electric Industries | Electrical conductor element such as a wire with an inorganic insulating coating |
| JPH1066288A (en) * | 1996-08-21 | 1998-03-06 | Ebara Corp | Highly-heat-resistant motor |
| CN113445088B (en) * | 2021-06-28 | 2021-12-14 | 沈伟 | Vapor chamber with high heat absorption and preparation method thereof |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56149775A (en) * | 1980-04-18 | 1981-11-19 | Agency Of Ind Science & Technol | Manufacture of oxide film for solid electrolyte of fuel cell |
| JPS60208494A (en) * | 1984-03-31 | 1985-10-21 | Kawasaki Steel Corp | Surface-treated steel sheet for seam welding can having excellent weldability |
| CA1295889C (en) * | 1985-01-14 | 1992-02-18 | Richard J. Penneck | Refractory coated article |
| CA1295890C (en) * | 1985-01-14 | 1992-02-18 | Stephen J. Duckworth | Electrical wire with refractory coating |
| JPS63239150A (en) * | 1987-03-27 | 1988-10-05 | Sumitomo Electric Ind Ltd | Production of superconductive ceramic thin film |
| JP2584626B2 (en) * | 1987-04-02 | 1997-02-26 | ペルメレツク電極株式会社 | Manufacturing method of colored titanium material |
| JPS63279524A (en) * | 1987-05-08 | 1988-11-16 | Sumitomo Electric Ind Ltd | Formation of superconductive thin film |
| JPS63281313A (en) * | 1987-05-12 | 1988-11-17 | Sumitomo Electric Ind Ltd | Heat-resistant electric wire |
| JP2642641B2 (en) * | 1987-09-21 | 1997-08-20 | 株式会社フジクラ | Superconductor |
-
1990
- 1990-03-20 JP JP2070843A patent/JP2890631B2/en not_active Expired - Lifetime
- 1990-03-26 KR KR1019900702515A patent/KR940000845B1/en not_active IP Right Cessation
- 1990-03-26 AU AU52736/90A patent/AU627859B2/en not_active Ceased
- 1990-03-26 DK DK90904938.9T patent/DK0416131T3/en active
- 1990-03-26 EP EP90904938A patent/EP0416131B1/en not_active Expired - Lifetime
- 1990-03-26 WO PCT/JP1990/000401 patent/WO1990011603A1/en active IP Right Grant
- 1990-03-26 CA CA002029868A patent/CA2029868C/en not_active Expired - Fee Related
- 1990-03-26 DE DE69013448T patent/DE69013448T2/en not_active Expired - Fee Related
-
1995
- 1995-06-15 HK HK96795A patent/HK96795A/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| DE69013448D1 (en) | 1994-11-24 |
| AU627859B2 (en) | 1992-09-03 |
| EP0416131B1 (en) | 1994-10-19 |
| KR920700456A (en) | 1992-02-19 |
| JPH0315113A (en) | 1991-01-23 |
| DK0416131T3 (en) | 1995-02-27 |
| EP0416131A4 (en) | 1992-11-25 |
| WO1990011603A1 (en) | 1990-10-04 |
| CA2029868A1 (en) | 1990-09-29 |
| EP0416131A1 (en) | 1991-03-13 |
| KR940000845B1 (en) | 1994-02-02 |
| AU5273690A (en) | 1990-10-22 |
| JP2890631B2 (en) | 1999-05-17 |
| HK96795A (en) | 1995-06-23 |
| DE69013448T2 (en) | 1995-02-23 |
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