JPH0765647A - Superconducting conductor and superconducting magnet device - Google Patents

Abstract

(57) [Summary] [Purpose] 800 ° C when a cable-in-conduit type superconducting coil is manufactured using compound superconducting materials.
(EN) Provided is a superconducting conductor which does not impair the insulating performance even after undergoing a heat treatment of a certain degree. [Structure] Superconducting wire (Nb3Sn, Nb3Al, etc.)
An internal cooling type superconducting conductor manufactured by accommodating (1) in a conduit (2) and further arranging an inorganic electrical insulating material (3) around the conduit (2) and the electrical insulating material (3). Is composed of a material with a coefficient of thermal expansion (thermal contraction rate) that is approximately the same from the temperature at which the conductor is used (-269 ° C) to the temperature (about 800 ° C) required for producing the compound superconducting conductor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for electrically insulating a superconducting magnet that undergoes high temperature heat treatment.

[0002]

2. Description of the Related Art For example, in a superconducting conductor used in a forced cooling type superconducting magnet used in a nuclear fusion device or the like, an organic material such as Kapton or epoxy resin is used as an insulating material between layers of the conductor or between turns. . The heat-resistant temperature of these insulating materials is at most about 200 ° C., and when using a compound-based superconducting material that requires heat treatment at about 800 ° C., the insulating treatment had to be performed after the heat treatment. In addition, although the inorganic insulating material has excellent heat resistance, after undergoing the heat treatment process, it is mechanically weakened, or cracks occur due to the difference in the coefficient of thermal expansion from the material to be insulated, etc. Often does not function as a material.

[0003]

Since the compound type superconducting conductor becomes ceramic after heat treatment, it is very vulnerable to deformation such as bending, and if the heat treatment is performed after the winding formation, the subsequent insulation treatment is extremely difficult. It was very difficult. The object of the present invention is to make the insulating material, even after undergoing heat treatment at about 800 ° C.,
It is to provide a configuration that does not lose its function.

[0004]

In order to achieve the above object, an insulating material such as a superconducting material or a conduit material is an inorganic insulating material having excellent heat resistance and a thermal expansion coefficient equal to that of the insulating material. It is effective to coat with alumina or zirconia. Further, as the coating method, it is preferable to use a sputtering method in which the superconducting material is less affected by heat history during coating.

[0005]

The above-mentioned inorganic insulating material has the same coefficient of thermal expansion from cryogenic temperature (4K) to heat treatment temperature (1000K) as that of the insulating material such as Nb3Sn material or titanium which is conduit material or InColoy908. It is not subjected to thermal stress, and as a result, even if it is an organic insulating material, it is possible to maintain electrical insulation performance without cracking.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 and 2 are Nb3S, respectively.
n shows a superconducting wire and a conduit material of titanium or InColoy908. Heat resistance on the surface of this conduit material 2,
Ceramics 3 such as alumina and zirconia, which have excellent abrasion resistance, abrasion resistance, and corrosion resistance, are coated on the order of several tens of μm.

In the case of a compound type superconducting wire or the like, a high temperature treatment of about 800 ° C. is carried out in order to produce a superconducting substance, but if an inorganic substance having high heat resistance is used, no thermal problem will occur. However, when a material having a thermal expansion coefficient different from that of a conduit material, which is an object to be insulated, is used, cracks or the like occur in the insulating material due to thermal stress caused by the difference in thermal expansion coefficient, and the electrical insulation performance is impaired. In this embodiment, alumina or zirconia is used as the insulating material 3 that is suitable when pure titanium or InColoy 908 is used as the conduit material 2 in order to prevent deterioration due to thermal strain of the superconducting material. Since this insulating material 3 has a thermal expansion coefficient substantially equal to that of a conduit material such as titanium, even if a heat treatment process is performed, thermal stress between the two substances does not occur and cracks can be prevented from occurring, resulting in electrical insulation performance. Will not hurt. Also, by using a sputtering method that can be processed at a low temperature (150 ° C) as a method for coating a ceramic material, it is possible to perform an insulation processing operation that does not adversely affect the superconducting material before heat treatment.

When the cable-in-conduit type superconducting coil used in a fusion reactor or the like is manufactured by using the compound type superconducting material with the above-mentioned structure, the insulation treatment can be performed before the heat treatment. It is possible to provide a configuration in which performance deterioration of the conductor does not easily occur.

In some cases, it is difficult to coat a structural material or conduit material with an inorganic material in a large superconducting coil. In such a case, as shown in FIG. 2, a thin titanium tape (several tens of microns) or the like is coated with an inorganic material. It is effective to insulate the insulator with a tape coated with several microns. Also, when this tape is wound around a rod-shaped object such as a conductor, cracks occur in the inorganic insulating material at the bent portions of the tape.
A method of arranging and placing the same type of tape or the like formed in a mold and winding the tape around this is effective.

[0010]

As described above, the superconducting conductor of the present invention is coated with an inorganic insulating material having the same coefficient of thermal expansion as that of the material to be insulated, so that the insulating ability is not deteriorated even after the heat treatment. It is possible to provide a high superconducting conductor.

[Brief description of drawings]

FIG. 1 is a sectional configuration diagram of a superconducting conductor according to an embodiment of the present invention.

FIG. 2 is an insulation configuration diagram of a superconducting conductor according to the present invention.

[Explanation of symbols]

 1 Superconducting wire 2 Conduit 3 Inorganic insulating material 4 Inorganic insulating tape 5 L type inorganic insulating tape

Claims (5)

[Claims] 1. An internal cooling type superconducting conductor manufactured by housing a compound superconducting wire in a conduit or the like, and further forming an electrically insulating layer of an inorganic material on the outer periphery thereof, wherein the conduit material and the insulating layer are conductors. From the operating temperature (-269 ℃) to the heat treatment temperature (about 800 ℃) to generate the compound superconductor
The superconducting conductor is composed of materials having substantially the same thermal expansion coefficient (thermal contraction coefficient). 2. A Nb3Sn material or an Nb3Al material is used as the superconducting wire, and pure Ti (titanium) or InColoy 908 is used as the conduit material, and a material having the same thermal contraction coefficient in the temperature range as the superconducting wire is used. As the insulating layer, the superconducting wire and the conduit material are made of alumina (Al ₂ O) having the same thermal shrinkage in the temperature range.
₃ ) Or zirconia (ZrO ₂ ) is used, The superconducting conductor according to claim 1. 3. The superconducting conductor according to claim 1, wherein the insulating layer is formed of a coating layer of several microns to several tens of microns by using a sputtering method, an ion plating method or the like. 4. The superconducting conductor according to claim 1, wherein a thin film metal is coated with an inorganic insulating material to form an insulating tape, and the insulating layer is formed thereby. 5. A superconducting magnet device using a compound-based superconductor, wherein an inorganic insulating material having a thermal expansion coefficient equal to that of the member is used as an insulating material of a member arranged in the magnet, and heat treatment is performed. A superconducting magnet device, characterized in that the insulating material is applied before to form a superconducting wire.