JP2011113933A - Superconducting wire, and superconducting coil using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting wire capable of reinforcing a layer constituting a superconducting member from stress generated in the superconducting member by manufacture and operation of a coil, and capable of reducing longitudinal stress generated in the superconducting member by a reinforcing means. <P>SOLUTION: The superconducting wire 1 includes: a superconducting member 2 composed by forming an oxide superconducting layer 7 on a substrate 5 having flexibility through an intermediate layer 6 and forming a protective layer 8 on the oxide superconducting layer 7; a reinforcing plate 3 brought into slide contact with a surface of the superconducting member 2 on the side formed with the oxide superconducting layer 7 for reinforcing a layer constituting the superconducting member 2; and an insulation tape 4 surrounding and constraining the superconducting member 2 and the reinforcing plate 3 mutually slidably in the longitudinal direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a superconducting wire having a multilayer structure and a superconducting coil using the same.

In a superconducting wire having a multilayer structure, an oxide superconducting layer having a uniform crystal orientation is formed on a substrate via an intermediate layer, and a protective layer is formed on the oxide superconducting layer. A superconducting wire having a multilayer structure is characterized by having a higher critical current density than a superconducting cable manufactured by enclosing a superconductor in a silver tube. However, when a superconducting coil is manufactured and operated using the superconducting wire of this multilayer structure, stress is generated in the superconducting wire during the manufacture and operation of the coil, and the layers constituting the superconducting wire are peeled, deformed, and cracked. As a result, the critical current density is lowered.

The stress generated in the layers constituting the superconducting wire of this multilayer structure is due to the difference in expansion coefficient of the layers constituting the superconducting wire during cooling of the superconducting coil, and due to the electromagnetic force acting on the oxide superconducting layer during superconducting coil operation. and so on.

Therefore, in order to prevent peeling, deformation, and generation of cracks due to stress caused by the above factors, a technique for reinforcing a layer constituting the superconducting wire by bonding a metal reinforcing plate to the protective layer of the superconducting wire with solder. It has been developed (for example, see Patent Document 1).

JP 2008-282854 A

However, using the superconducting wire of the technique described in Patent Document 1, when the superconducting wire is arranged on the inner periphery and the reinforcing plate is arranged on the outer periphery and wound on the winding core to produce the superconducting coil, the curvature of the superconducting wire and the reinforcing plate is obtained.・ Since the radius is different, the winding distance of the reinforcing plate is longer than the superconducting wire, and since the superconducting wire and the reinforcing plate are bonded, the stress in the longitudinal direction is such that the reinforcing plate pulls the superconducting wire in the winding direction. Has occurred in the layers constituting the superconducting wire.

In addition, a bending stress is generated in the reinforcing plate during winding, thereby generating a compressive stress in the longitudinal direction on the inner surface of the winding of the reinforcing plate. Since the superconducting wire and the reinforcing plate are bonded, this compressive stress Longitudinal stress was generated in the layers constituting the superconducting wire.

Therefore, the technique described in Patent Document 1 causes the layer constituting the superconducting wire to peel, deform, and crack due to the longitudinal stress generated in the layer constituting the superconducting wire by the reinforcing plate as described above. As a result, there has been a new problem that the critical current density is lowered.

Accordingly, the present invention reinforces the stress in the layer constituting the superconducting wire due to the manufacture and operation of the superconducting coil, and reduces the longitudinal stress generated in the layer constituting the superconducting wire by the reinforcing means. It is an object to provide a superconducting wire that can be used.

In order to achieve the above object, in the superconducting wire of the present invention, an oxide superconducting layer is formed on a flexible substrate via an intermediate layer, and a protective layer is formed on the oxide superconducting layer. A superconducting member comprising: a reinforcing plate that is slidably contacted with the surface of the superconducting member on which the protective layer is formed; and an insulating tape that surrounds and restrains the superconducting member and the reinforcing plate so as to be slidable in the longitudinal direction. The reinforcing plate reinforces in the stacking direction against stress generated in the intermediate layer, the oxide superconducting layer, and the protective layer.

According to the present invention, the lamination direction is reinforced with respect to the stress generated in the layer constituting the superconducting wire by the production and operation of the superconducting coil, and the longitudinal stress generated in the layer constituting the superconducting wire is reduced by the reinforcing means. can do.

Sectional drawing of a surface perpendicular | vertical to the longitudinal direction of the superconducting wire which concerns on the 1st Embodiment of this invention. The perspective view which shows how to wind the insulating tape which concerns on the 1st Embodiment of this invention. Sectional drawing of a surface perpendicular | vertical to a longitudinal direction at the time of using multiple superconducting layer members of the superconducting wire which concerns on the 1st Embodiment of this invention. Sectional drawing of a surface perpendicular | vertical to a longitudinal direction at the time of facing two superconducting layer members of the superconducting wire which concerns on the 1st Embodiment of this invention. The superconducting coil using the superconducting wire which concerns on the 1st Embodiment of this invention is shown, (a) is a cross-sectional perspective view, (b) is an expanded sectional view. Sectional drawing of a surface perpendicular | vertical to the longitudinal direction of the superconducting wire which concerns on the 2nd Embodiment of this invention.

  Embodiments of the present invention will be described below.

(First embodiment)
(Constitution)
Hereinafter, the configuration of the superconducting wire according to the first embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a cross-sectional view of a surface perpendicular to the longitudinal direction of a superconducting wire according to the first embodiment of the present invention.

In the superconducting member 2, an intermediate layer 6 is formed on a tape-shaped substrate 5 having a thickness of 0.1 mm and a width of 4.0 mm, and an oxide superconducting layer 7 having excellent crystal orientation is formed on the intermediate layer 6. The protective layer 8 is formed on the oxide superconducting layer 7, and the stabilization layer 9 is formed on the protective layer 8.

The superconducting wire 1 is in sliding contact with a reinforcing plate 3 having a thickness of 0.1 mm and a width of 4.0 mm as a reinforcing means on the surface of the superconducting member 2 on which the stabilization layer 9 is formed. It is configured by surrounding and restraining the reinforcing plate 3 so as to be slidable with respect to each other in the longitudinal direction.

FIG. 2 is a perspective view showing how to wind the insulating tape according to the first embodiment of the present invention. The insulating tape 4 surrounds the superconducting member 2 and the reinforcing plate 3 by a method of winding in an oblique direction so as to overlap the wound portions, which is called wrapping.

The substrate 5 is made of a high-strength metal material such as Hastelloy (registered trademark), stainless steel, or nickel alloy. Non-metallic materials such as glass and ceramics are also applicable.

The intermediate layer 6 includes yttrium-stabilized zirconia (YSZ), cerium oxide (CeO ₂ ),
By using a material having excellent crystal orientation such as SrTiO ₃ and MgO and having a coefficient of expansion close to that of the oxide superconducting layer 7, heat caused by the difference in thermal expansion between the substrate 5 and the oxide superconducting layer 7 can be obtained. Prevent distortion.

The oxide superconducting layer _{7, Y 1 Ba 2 Cu 3} O 7-x, Y 2 Ba 4 Cu 8 Ox, Y 3 Ba 3
Cu ₆ Ox composition, or (Bi, Pb) ₂ Ca ₂ Sr ₂ Cu ₃ Ox, (Bi, Pb
_{) 2 Ca 2 Sr 3 Cu 4} Ox having a composition, _{or, Tl 2 Ba 2 Ca 2 Cu} 3 Ox, Tl
₁ Ba ₂ Ca ₂ Cu ₃ Ox, Tl ₁ Ba ₂ Ca ₃ Cu ₄ Ox, which is composed of an oxide superconductor with a high critical temperature typified by a composition, etc., and is formed on the surface of the intermediate layer 6 by a laser deposition apparatus or the like. .

The protective layer 8 is made of silver as a material, and is formed on the surface of the oxide superconducting layer 7 by a vacuum deposition method or the like. Here, the silver used for the protective layer 8 has a function of preventing oxygen contained in the oxide superconductor from diffusing from the oxide superconductor layer 7 and maintaining the composition of the oxide superconductor. As long as the substance has this effect, materials other than silver, such as gold and platinum, can be applied.

The stabilization layer 9 is formed on the surface of the protective layer 8 by a method such as plating with a highly conductive metal such as copper or Al. In addition, in order to facilitate the formation of the stabilization layer 9, a structure in which a base stabilization layer made of silver, gold, platinum, or the like is previously formed on the protective layer 8 and the stabilization layer 9 is formed thereon. Also good.

If the superconducting coil is used in excess of the critical current, the superconducting state cannot be maintained, and a part of the oxide superconducting layer changes to a normal conductor having high electrical resistance. At this time, heat is generated by the current flowing through the normal conductor, which is called a quench phenomenon, and this part further changes to the normal conductor. The phenomenon of vaporization may occur.

The stabilization layer 9 acts as a detour path for excess current to the oxide superconducting layer 7 when a current exceeding the critical current flows through the oxide superconducting layer 7 in order to prevent a quench phenomenon of the superconducting coil. It has.

The reinforcing plate 3 functions to reinforce the superconducting member 2, and metals such as copper and stainless steel are used. However, materials other than metals such as synthetic resins and ceramics can be used as long as they are resistant to bending strain and tension. Is possible.

The insulating tape 4 is a tape made of an insulating material. For example, Kapton (trademark registration) or Nomex (trademark registration) can be used.

FIG. 3 is a cross-sectional view of a surface perpendicular to the longitudinal direction when a plurality of superconducting members of the superconducting wire according to the first embodiment of the present invention are provided. The reinforcing plate 3 is slidably brought into contact with the surface of the first superconducting member 2a on which the stabilization layer 9a is formed, and the second superconducting member 2b is further stabilized under the surface of the substrate 5a of the first superconducting member 2a. The insulating layer 4 slidably contacts the two superconducting members 2a and 2b and the reinforcing plate 3 so as to be slidable and restrained with each other. Alternatively, the superconducting member 2 may be further provided in sliding contact with the surface on which the stabilization layer 9 is formed below the surface of the substrate 5 of the second superconducting member 2b.

FIG. 4 is a cross-sectional view of a plane perpendicular to the longitudinal direction when two superconducting members of the superconducting wire according to the first embodiment of the present invention face each other. The reinforcing plate 3 is omitted, and the first and second superconducting members 2
a, the surfaces of the a and 2b on which the stabilizing layers 9a and 9b are formed are in sliding contact with each other, and the two superconducting members 2a and 2b are slidably surrounded by the insulating tape 4 and restrained. To do.

FIG. 5 shows a superconducting coil using the superconducting wire according to the first embodiment of the present invention.
Is a sectional perspective view, and (b) is an enlarged sectional view. The core 12 has an inner diameter of 90 mm and an outer diameter of 100 mm.
It is made of a material such as FRP. The resin 13 is made of a curable resin such as an epoxy resin.

The superconducting coil 11 is obtained by applying a resin 13 to the superconducting wire 1, winding the reinforcing plate 3 on the outer periphery and winding the superconducting member 2 on the core 12 for 20 turns and impregnating with the resin 13. is there. The superconducting coil 11 may be manufactured by winding the reinforcing plate 3 on the inner periphery and the superconducting member 2 on the outer periphery.

(Function)
The reinforcing plate 3 is slidably brought into contact with the surface of the superconducting member 2 on which the stabilizing layer 9 is formed, and the superconducting member 2 and the reinforcing plate 3 are slidably surrounded by the insulating tape 4 and restrained. If
Since the superconducting member 2 and the reinforcing plate 3 are constrained in the stacking direction by the insulating tape 4, the reinforcing plate 3 is against the stress generated in the layers constituting the superconducting member 2 due to the difference in thermal expansion coefficient or electromagnetic force. Reinforce the stacking direction.

In addition, since the superconducting member 2 and the reinforcing plate 3 are slidable in the longitudinal direction, the superconducting member 2 and the reinforcing plate 3 are in the longitudinal direction even if longitudinal stress is applied to the superconducting member 2 by the reinforcing plate 3. They slide to each other in the direction of releasing the stress, and the stress is reduced.

When the second superconducting member 2b is brought into sliding contact with the surface on the side where the stabilization layer 9b is formed below the surface of the substrate 5 of the first superconducting member 2a, the reinforcing plate 3 becomes the first superconducting member. In addition to reinforcing the layer constituting the layer 2b in the stacking direction, the substrate 5a of the first superconducting member 2a acts as a reinforcing means on the layer constituting the second superconducting member 2b in the same manner as the reinforcing plate 3. 1 superconducting member 2a
The substrate 5a reinforces the layers constituting the second superconducting member 2b in the stacking direction. Further, the first and second superconducting members 2a and 2b and the reinforcing plate 3 slide with respect to the stress in the longitudinal direction,
Stress is reduced.

When the first and second superconducting members 2a and 2b are brought into sliding contact with the surfaces on which the stabilization layers 9a and 9b are formed facing each other, the substrates 5a and 5b serve as the first and second reinforcing members. The layers constituting the superconducting members 2a and 2b are reinforced in the stacking direction. Further, the superconducting members 2 slide with respect to the stress in the longitudinal direction, and the stress is reduced.

When the superconducting coil 11 is manufactured by winding the reinforcing plate 3 on the inner periphery and the superconducting member 2 on the outer periphery, stress opposite to the above-described longitudinal stress is applied to the superconducting member 2. ,
The superconducting member 2 and the reinforcing plate 3 slide in the longitudinal direction with respect to the direction in which the stress is released, thereby reducing the stress.

(effect)
According to this embodiment, the longitudinal direction generated in the layer constituting the superconducting member 2 by the reinforcing means is performed in the lamination direction with respect to the stress generated in the layer constituting the superconducting member 2 by the production and operation of the superconducting coil 11. Peeling of the layers constituting the superconducting member 2 by reducing the stress of
Deformation, cracks and the like can be prevented, and a decrease in the critical current density of the superconducting coil 11 can be prevented.

(Second Embodiment)
Next, a superconducting wire according to a second embodiment of the present invention will be described with reference to FIG. This embodiment is different from the first embodiment in that a release agent 10 is newly provided. The same parts as those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

FIG. 6 is a cross-sectional view of a surface perpendicular to the longitudinal direction of the superconducting wire according to the second embodiment of the present invention. The superconducting wire 1 of this embodiment includes a surface of the superconducting member 2 on the side where the stabilization layer 9 is formed and a reinforcing plate 3.
A release agent 10 is provided between them, and the superconducting member 2 and the reinforcing plate 3 are surrounded and restrained by the insulating tape 4 so as to be slidable in the longitudinal direction.

As the release agent 10, for example, a fluorine resin such as Teflon (registered trademark), paraffin grease, silicon oil, or the like is used. When using a fluororesin, it is preferable to use a fluororesin tape. The release agent 10 does not have to be provided on the entire surface where the superconducting member 2 and the reinforcing plate 3 are in sliding contact with each other, and may be provided only on a portion that exhibits the effect.

Further, when two or more superconducting members 2 in the first embodiment are slidably contacted in the same stacking direction, or when two superconducting members 2 face each other and are slidably contacted with each other, the superconducting members 2 are separated from the surface where they are slidably contacted The agent 10 is provided.

(Function)
The release agent 10 reduces friction generated between the superconducting member 2 and the reinforcing plate 3 or on the surface where the superconducting members 2 are in sliding contact with each other.

(effect)
According to the present embodiment, in addition to the effects of the first embodiment, the release agent 10 can promote the sliding of the superconducting member 2 and the reinforcing plate 3 or between the superconducting members 2 in the longitudinal direction.

Needless to say, the embodiment of the present invention is not limited to the above-described embodiment. For example, the dimensions of the above-described superconducting wire 1 and coil core 12 can be changed in a timely manner, and the method of enclosing the superconducting member 2 and the reinforcing plate 3 of the insulating tape 4 is not limited to the above-described wrap winding. Surrounding the superconducting tape 2 and the reinforcing plate 3 with the insulating tape 4 so as to be slidable in the longitudinal direction, such as a method in which the superconducting member 2 and the reinforcing plate 3 are sandwiched and fixed at both ends with an adhesive or the like. Any other method can be applied.

Further, the protective layer 8 can also serve as the stabilizing layer 9, and at this time, the superconducting member 2
May be configured such that the stabilization layer 9 is not formed. The stabilizing layer 9 includes at least the protective layer 8.
The stabilization layer 9 may be formed on the entire surface of the laminate composed of the substrate 5, the intermediate layer 6, the oxide superconducting layer 7, and the protective layer 8.

DESCRIPTION OF SYMBOLS 1 ... Superconducting wire 2, 2a, 2b ... Superconducting member 3 ... Reinforcing plate 4 ... Insulating tape 5 ... Substrate 6 ... Intermediate layer 7 ... Oxide superconducting layer 8 ... Protective layer 9, 9a, 9b ... stabilizing layer 10 ... release agent 11 ... superconducting coil 12 ... core 13 ... resin

Claims (8)

A superconducting member in which an intermediate layer is formed on a flexible substrate, an oxide superconducting layer is formed on the intermediate layer, and a protective layer is formed on the oxide superconducting layer;
A reinforcing plate in sliding contact with the surface of the superconducting member on the protective layer side;
A superconducting wire comprising an insulating tape that surrounds and restrains the superconducting member and the reinforcing plate so as to be slidable with respect to each other in the longitudinal direction. An intermediate layer is formed on a flexible substrate, an oxide superconducting layer is formed on the intermediate layer, and at least two superconducting members having a protective layer formed on the oxide superconducting layer are arranged in the same stacking direction. A stack of slidable layers,
A reinforcing plate in sliding contact with the surface on the protective layer side of the laminate;
A superconducting wire comprising the superconducting member, the reinforcing plate, and an insulating tape that surrounds and restrains the laminate and the reinforcing plate so that the superconducting members can slide in the longitudinal direction. An intermediate layer is formed on a flexible substrate, an oxide superconducting layer is formed on the intermediate layer, and a superconducting member having a protective layer formed on the oxide superconducting layer is formed on the surface on the protective layer side. A pair of superconducting members that are in sliding contact with each other,
A superconducting wire comprising an insulating tape that surrounds and restrains the pair of superconducting members so as to be slidable relative to each other in the longitudinal direction. The superconducting wire according to claim 1 or 2, wherein a release agent is further provided on a surface where the superconducting member and the reinforcing plate are in sliding contact with each other. 4. The superconducting wire according to claim 2, wherein a release agent is further provided on a surface where the superconducting members are in sliding contact with each other. The superconducting wire according to any one of claims 1 to 5, wherein the superconducting member further includes a stabilization layer formed on at least a surface of the protective layer on a surface of the superconducting member. The superconducting device according to any one of claims 1 to 6, wherein the insulating tape is surrounded by being wound so that a portion of the insulating tape overlaps in an oblique direction with respect to a longitudinal direction. line. A superconducting coil comprising the superconducting wire according to any one of claims 1 to 7 wound thereon.

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