EP0729157A1 - Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung - Google Patents
Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung Download PDFInfo
- Publication number
- EP0729157A1 EP0729157A1 EP95102703A EP95102703A EP0729157A1 EP 0729157 A1 EP0729157 A1 EP 0729157A1 EP 95102703 A EP95102703 A EP 95102703A EP 95102703 A EP95102703 A EP 95102703A EP 0729157 A1 EP0729157 A1 EP 0729157A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- oxide layer
- oxide
- coating solution
- conductor
- electrical conductor
- 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.)
- Granted
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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
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- 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
-
- 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
- H01B7/295—Protection against damage caused by extremes of temperature or by flame using material resistant to flame
Definitions
- the present invention relates to an electrically conducting wire with an insulating coating made of an inorganic material.
- a wire is used for high temperature operating conditions, e.g. as an insulated lead wire or the like.
- An insulated conductor such as a wire or a member for a thermocouple is generally used in equipment such as heating equipment or fire alarm devices, which require safe operation at high operating temperatures. Such an insulated wire is also employed in an automobile in an environment which is heated to a high temperature.
- An insulated wire of this type is generally formed by a conductor which is coated with a heat-resistant organic resin such as polyimide, fluororesin or the like.
- Such a resin-coated wire can merely withstand a temperature of about 300°C at the most.
- a wire which is employed in a high vacuum apparatus for example, must have high heat resistance against baking, etc., a small emission characteristic as to absorbed gas and water for achieving and maintaining a high degree of vacuum, and a small emission of gases caused by thermal decomposition. It is impossible to satisfy such requirements for heat resistance and a non-outgassing property with a conventional wire which is coated with an organic material insulation.
- an insulated wire is comprising a conductor which passes through an insulator tube of ceramics
- an MI (mineral insulated) cable comprising a conductor which passes through a tube of a heat-resistant alloy, such as stainless steel alloy, that is filled with fine particles of a metal oxide such as magnesium oxide, or the like is generally used.
- a glass braided tube insulated wire employing an insulating member of glass fiber fabric or the like is known as an insulated, heat resistant, flexible wire.
- wires coated with organic materials were studied.
- wires have been proposed, one of which is obtained by anodizing an aluminum (Al) conductor for forming an Al oxide layer on the outer wire surface, and another wire is obtained by mixing a frit prepared by mixing various metal oxides with each other and melting and pulverizing the as-obtained mixture for forming a slip, applying this slip to a metal conductor and heating and melting the same for forming a homogeneous composite metal oxide layer or coating on the wire surface.
- the wire with an aluminum oxide layer is not suitable for use as a heat resistant wire since this technique is merely applicable to an aluminum conductor having a low melting point, while the as-formed film is so porous that the wire has an inferior moisture resistance and a low breakdown voltage.
- the wire with a composite metal oxide coating is applicable to a metal conductor of copper (Cu) or nickel (Ni) having a higher heat resistance.
- this technique is merely applicable to a metal composite oxide whose melting point is lower by about 300 to 400°C than those of Cu and Ni since the metal composite oxide layer is formed through a melting process, and the heat resistance temperature is restricted below the just mentioned level.
- the as-formed wire is inferior in flexibility since it is difficult to reduce the thickness of the film.
- the overall diameter is increased as compared with the conductor diameter, leading to an inferior space factor. Thus, it is impossible to feed a high current.
- the inorganic insulating member or electrical conductor wire according to the present invention comprises a conductor of Ni or Ni alloy, an oxide layer of an oxide of the Ni or Ni alloy on an outer surface of the conductor, said oxide layer being obtained by oxidizing the conductor in a vapor phase containing oxygen, and an oxide layer of aluminum (Al) and/or silicon (Si) is provided on an outer surface of the oxide layer of Ni or Ni alloy.
- the oxide layer of Al and/or Si is an oxide layer obtained by applying a solution prepared by hydrolyzing and polycondensing alkoxide of Al and/or Si in a solvent, drying the same for allowing gelation, and thereafter heating the obtained gel.
- the oxide layer of Al and/or Si has a melting point exceeding that of Ni or Ni alloy.
- the inorganic insulated member according to the present invention is applied to or used as a heat resistant wire or an incombustible wire at a high temperature which does not permit using an organic insulating material, for example.
- the present invention is not restricted to such a wire, but is also applicable to another member such as a thermocouple.
- Fig. 1 shows an Ni core conductor 1 coated with an Ni oxide layer 2 formed around the core conductor.
- An Al oxide layer 3 is formed around the Ni oxide layer 2. The formation of these oxide layers will be described in more detail below.
- Fig. 2 shows a nickel alloy conductor 11 first coated with an Ni alloy oxide layer 12 formed around the Ni alloy conductor 11.
- An Si oxide layer 13 is formed around the Ni alloy oxide layer 12.
- the nickel Ni core conductor 21 is first coated with an Ni oxide layer 22 formed around the Ni core conductor 21.
- An Si oxide layer 23 is formed around the Ni oxide layer 22.
- an Al oxide layer or Si oxide layer 24 is formed around the Si oxide layer 23.
- a nickel alloy core conductor 31 is first coated with an Ni alloy oxide layer 32 formed around the Ni alloy core conductor 31. Then, an Al-Si composite oxide layer 33 is formed around the Ni alloy oxide layer 32.
- a first oxide layer of Ni or an Ni alloy is first formed on an outer surface of a conductor of Ni or Ni alloy by oxidizing the conductor in a vapor phase containing oxygen. Then, a second oxide layer of Al and/or Si is formed on the first oxide layer.
- Ni or Ni alloy is an inactive metal which has an inferior affinity for a metal oxide of Al or Si.
- a surface of Ni or Ni alloy is directly coated with such an Al or Si oxide, a rather poor adhesion is obtained and the coating is immediately separated from the Ni or Ni alloy.
- the present invention teaches to first oxidize a core conductor of Ni or Ni alloy in a vapor phase containing oxygen, so as to form an oxide layer of Ni or Ni alloy.
- the so formed nickel oxide layer or Ni alloy oxide layer very strongly adheres to the surface of the Ni or Ni alloy. This strong bonding is due to the fact that the nickel oxide or the nickel alloy oxide has an excellent affinity for the nickel or nickel alloy.
- the nickel or nickel alloy oxide has a strong affinity to aluminum oxide or silicon oxide and hence also strongly bonds to the outer layer of Al or Si oxide and to the conductor core. According to the present invention, therefore, the oxide layer of Al and/or Si is not separated for all practical purposes from the intermediate oxide layer, whereby an excellent flexibility is obtained when the inorganic insulating coating is applied to a wire forming a core conductor, for example.
- the oxide layer of Al and/or Si is obtained by applying a solution prepared by hydrolyzing and polycondensing an alkoxide of Al and/or Si in a solvent, drying the same for allowing gelation, and thereafter heating the so-obtained gel.
- the Al and/or Si oxide layer formed in the aforementioned manner has a melting point exceeding that of the Ni or Ni alloy. Additionally, the Al and/or Si oxide layer is formed without any melting process.
- the critical temperature to which conductors or other members of the present invention with their inorganic insulating coatings may be exposed in operation is not restricted by the melting point of the oxide layer. Rather, the present insulating members can be heated to a temperature limited only by the melting point of the Ni core or the Ni alloy core.
- the oxide layer formed in the aforementioned manner has characteristics such as an extreme denseness, a smooth surface and a small adsorption of gases, e.g. steam or the like.
- the present members have an excellent insulability and a high moisture resistance.
- Preferred embodiments have been produced as two conductors C1 and C2 which were oxidized as follows.
- All the coating operations were, for example, performed by dipping the wire into the respective coating solution.
- the above Table shows the breakdown voltages and the flexibility values of the wires of Examples 1 to 4 of the invention and of the two Comparative Examples.
- the flexibility values were evaluated in terms of diameter ratios, by winding the wires on circular cylinders of a prescribed diameter D and measuring the minimum diameters causing no separation of the insulating inorganic compound coatings or layers from the conductor core.
- the diameter D was 0.5 mm.
- the inorganic insulating coating on a conductor wire according to the present invention forms an insulating inorganic compound layer which is well bonded to the conductor core and has an excellent heat resistance and insulability.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Insulated Conductors (AREA)
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP95102703A EP0729157B1 (de) | 1995-02-24 | 1995-02-24 | Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung |
DE1995602270 DE69502270T2 (de) | 1995-02-24 | 1995-02-24 | Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP95102703A EP0729157B1 (de) | 1995-02-24 | 1995-02-24 | Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0729157A1 true EP0729157A1 (de) | 1996-08-28 |
EP0729157B1 EP0729157B1 (de) | 1998-04-29 |
Family
ID=8219011
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP95102703A Expired - Lifetime EP0729157B1 (de) | 1995-02-24 | 1995-02-24 | Elektrisches Leiterelement wie ein Draht mit anorganischen Isolierbeschichtung |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP0729157B1 (de) |
DE (1) | DE69502270T2 (de) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7935885B2 (en) | 2008-07-11 | 2011-05-03 | Ford Global Technologies, Llc | Insulated assembly of insulated electric conductors |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7572980B2 (en) | 2007-01-26 | 2009-08-11 | Ford Global Technologies, Llc | Copper conductor with anodized aluminum dielectric layer |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0292780A1 (de) * | 1987-05-12 | 1988-11-30 | Sumitomo Electric Industries, Ltd. | Elektrischer Draht |
EP0416131A1 (de) * | 1989-03-28 | 1991-03-13 | Sumitomo Electric Industries, Ltd. | Isolierte elektrische litze |
EP0494424A1 (de) * | 1991-01-10 | 1992-07-15 | Sumitomo Electric Industries, Limited | Anorganische Isolierung |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CA1295890C (en) * | 1985-01-14 | 1992-02-18 | Stephen J. Duckworth | Electrical wire with refractory coating |
-
1995
- 1995-02-24 EP EP95102703A patent/EP0729157B1/de not_active Expired - Lifetime
- 1995-02-24 DE DE1995602270 patent/DE69502270T2/de not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0292780A1 (de) * | 1987-05-12 | 1988-11-30 | Sumitomo Electric Industries, Ltd. | Elektrischer Draht |
EP0416131A1 (de) * | 1989-03-28 | 1991-03-13 | Sumitomo Electric Industries, Ltd. | Isolierte elektrische litze |
EP0494424A1 (de) * | 1991-01-10 | 1992-07-15 | Sumitomo Electric Industries, Limited | Anorganische Isolierung |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7935885B2 (en) | 2008-07-11 | 2011-05-03 | Ford Global Technologies, Llc | Insulated assembly of insulated electric conductors |
Also Published As
Publication number | Publication date |
---|---|
DE69502270D1 (de) | 1998-06-04 |
DE69502270T2 (de) | 1999-01-07 |
EP0729157B1 (de) | 1998-04-29 |
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