JPH08212846A - Oxide superconductive wire rod, its manufacture and superconductive coil using it - Google Patents

Abstract

PURPOSE: To provide an oxide superconductive wire excellent in superconductive characteristic which is operated by use of liquid nitrogen as coolant. CONSTITUTION: This oxide superconductive wire is characterized by forming oxide superconductor layers 3 through silver or silver alloy layers 2 on at least both surfaces of a base material 1 consisting of metal or ceramics. Both the surface of the base material 1 are nipped by the base materials 2 and the superconductor layers 3 consisting of the same structural material, whereby the warpage or deformation based on the difference in thermal expansion coefficient among the base material 1, the base material 2, and the superconductor layer 3 is minimized, the cracking of the super conductor layer 3 can be prevented, and an oxide superconductive wire rod excellent in superconductive characteristic can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide superconducting wire which exhibits superconductivity by cooling with liquid helium or liquid nitrogen and a method for producing the same.

[0002]

2. Description of the Related Art Oxide superconductors have a plate-like crystal form and have a large aspect ratio (ratio of crystal grain size to crystal thickness). Although it is easily oriented by such a mechanical process, the pinning force at 77K is weak, and thus the superconducting property is lost in a magnetic field of 1 T (tesla) or more, which makes practical application difficult.

On the other hand, thallium-based superconductors having a small aspect ratio are available in Japanese Journal of Applied Physics (Jpn. J. Appl. Phy).
s. ) 32, p. 484, 7
Even if a magnetic field of 1 T or more is vertically applied to the superconductor at 7K, the transport current (Jc) can be passed. Therefore, application as a wire rod has been tried.

However, when the wire-drawing rolling method, which is most suitable for mass production, is used as a wire rod forming process, Tl
In the superconductors, the crystal aspect ratio was so small that the crystals could not be oriented. The Journal of
Applied Physics (J. Appl. Phy
s. ) As described in Volume 32, page 2634,
The Tl-based superconductor is a polycrystalline body, and when the crystal orientation is random, the crystal becomes a weak junction at the grain boundary, and Jc suddenly increases in a weak magnetic field.
There is a problem that

In order to reduce the effect of weak grain boundary bonding, it is effective to orient the crystal direction of the superconductor in a fixed direction. That is, how to orient the crystal of such a superconductor is the key to practical use.

As a method of the above-mentioned orientation, a method of depositing a thin superconductor layer on the substrate to form oriented crystals from the interface of the substrate is effective.

When a wire is formed using such a thin film method, the thickness of the superconductor layer is 0.1 to 5 μm, and the thickness of the metal base material carrying the superconductor layer is 10 to 100 μm. Moreover, the Jc of the wire rod overall is low. Therefore, how to form a film on a thin metal substrate,
The issue is whether to form films continuously.

At present, it has been found that silver and silver alloys are promising as the base material of the superconducting wire. However, when a film is formed on a thin silver or silver alloy base material, handling becomes a problem due to insufficient strength, and it is difficult to produce a practical long wire.

[0009]

In the wire-drawing rolling method according to the prior art described above, the orientation of the crystals in the superconducting wire is random, and the grain boundary bonding of the crystal grains becomes weak grain boundary bonding, resulting in a decrease in Jc.

On the other hand, in the process of forming a thin superconducting layer on a tape-shaped metal substrate, since the crystals are oriented in the c-axis and in-plane, Jc does not drop sharply in the magnetic field.
However, when a wire rod is manufactured using a thin film method, unless the thickness of the base material is reduced, a high overall Jc is obtained.
You cannot get a wire rod with.

At present, silver and silver alloys used as a base material for a superconductor have problems such as deformation during heat treatment, bending strain in the superconductor, and difficulty in coil forming.

An object of the present invention is to use an oxide superconductor,
An object is to provide a high overall Jc oxide superconducting wire and a method for producing the same.

Another object of the present invention is to provide a superconducting device such as a superconducting coil or a superconducting magnet using the superconducting wire.

[0014]

The gist of the present invention for achieving the above object is as follows.

[1] An oxide superconducting wire in which an oxide superconducting layer is formed on at least both front and back surfaces of a base material made of metal or ceramics with a silver or silver alloy layer interposed therebetween.

[2] A step of forming an oxide superconductor material (or a raw material thereof) on a tape-shaped base material made of silver or a silver alloy, and the oxide superconductor on at least both front and back surfaces of the base material made of metal or ceramics. A process for producing an oxide superconducting wire, which comprises a step of laminating a tape-shaped base material on which a material is formed to form a composite, and a step of firing the composite material to make the oxide superconductor material a superconductor.

[3] A superconducting coil formed by winding an oxide superconducting wire having an oxide superconducting layer formed on at least both front and back surfaces of a base material made of metal or ceramics with a silver or silver alloy layer interposed therebetween.

[4] A plurality of layers obtained by winding an oxide superconducting wire in which an oxide superconducting layer is formed with a silver or silver alloy layer interposed between at least both front and back surfaces of a base material made of metal or ceramics. A superconducting magnet having a formed coil.

In the present invention, the oxide superconductor used is a Tl system or Bi system in which the c-axes of the crystals are aligned in the same direction.
And Y-based superconductors are preferred.

The base material is Al, Ni, Cu-Al.
Alloy, NiO, Al ₂ O ₃ , YSZ, SrTiO ₃ , Mg
A material selected from O, ZrO and the like is used.

The structure of the oxide superconducting wire of the present invention will be specifically described below with reference to the drawings.

FIG. 1 shows a schematic cross section of a superconducting wire in which a superconducting layer 3 formed on a base material 2 made of silver or a silver alloy is bonded to both sides of a base material 1 made of metal or ceramics. .

In the heat treatment step of the superconductor, the material forming the base material 1 may diffuse from the grain boundaries of the silver or silver alloy of the base material 2 and react with the superconductor.
It is required that the metal or ceramic material constituting the material is stable. Therefore, Ni, Al, Cu-Al, etc., which can form an oxide film by heat treatment, NiO, Al
A ceramics nonwoven fabric such as ₂ O ₃ , SrTiO ₃ , MgO, ZrO or flexible YSZ is used as a base material.

This composite tape-shaped superconducting wire is capable of suppressing deformation of the superconducting layer during heat treatment, does not generate microcracks in the superconducting layer, and provides superconducting characteristics. it can.

A specific method for producing the oxide superconducting wire of the present invention is to immerse the oxide superconducting material (or its raw material) in a liquid dissolved or dispersed in a solvent, or atomize the liquid to form a tape. The base material 2 having the superconductor layer produced by depositing on the base material 2 can be produced by bonding the both surfaces of the base material 1 with silver paste.

In the schematic cross-sectional view of FIG. 1, the superconductor layer 3 is provided only on both sides of the base material 1 with the base material 2 interposed therebetween. As shown in the schematic cross-sectional view of FIG. It is preferable that the base material 1 has a structure in which the base material 2 and the superconductor layer 3 are wrapped around the base material 1 because the reliability is more excellent. In this case, the base material 2 can be manufactured by forming the base material 2 on which the superconductor layer 3 having a width about twice that of the base material 1 is formed and wrapping the base material 1 with this.

On the other hand, in the superconducting wire (comparative example) in which the superconductor layer 3 is formed only on one surface of the base material 1 with the base material 2 interposed therebetween, the coefficient of thermal expansion of the superconductor layer 3 and the base materials 1 and 2 is large. Since they are different, microcracks are likely to occur in the superconductor layer, and as is clear from Table 1, it can be seen that there is a considerable difference in Jc of the wire material in which the Tl-based superconductor layer is formed on the Ni-based alloy via silver.

In the present invention, the film thickness of the superconductor layer is 1
While the film thickness and Ic show a nearly proportional relationship up to 0 μm, the comparative example shows a low Ic value.

[0029]

[Table 1]

Next, an example of an apparatus for manufacturing the superconducting wire according to the present invention by the dip coating method will be described with reference to the schematic view of FIG.

A tape-shaped substrate 2 made of silver or a silver alloy having a masking tape 14 on one side is continuously contacted with a slurry 16 in which a superconductor material (or a raw material thereof) is dissolved or dispersed in a solvent (this). If so, it is deposited on the base material 2. Next, by removing the masking tape 14, one surface of the tape-shaped base material 2 made of silver or a silver alloy is exposed, and the base material 1 made of metal or ceramics is brought into contact with this surface. In this way, the base material 2 provided with the superconductor layer 3 on the base material 1 is continuously bonded, surrounded, or adhered to produce the composite tape-shaped base material 7.
Then, a heat treatment is performed under predetermined conditions to produce a superconductor wire.

FIG. 4 is a schematic view showing an example of an apparatus for producing the superconducting wire according to the present invention by the spray pyrolysis method.

A mist 18 in which a superconductor material (or its raw material) is dissolved or dispersed in a solvent is sprayed and deposited on a tape-shaped substrate 2 made of silver or a silver alloy. Next, the composite tape-shaped base material 7 (superconductor wire) can be produced by continuously bonding, enclosing, or adhering to the base material 1 in the same manner as described above. Then, a heat treatment is performed under predetermined conditions to produce a superconductor wire.

[0034]

The superconducting wire of the present invention has excellent superconducting properties because it has the same constituent material and almost the same film thickness on both front and back surfaces of the base material 1 such as ceramics through the base material 2 made of silver or silver alloy. The structure is sandwiched between the superconductor layers. As a result, the warpage and deformation due to the difference in the coefficient of thermal expansion of the base material 1, the base material 2 and the superconductor layer are offset, so that the superconducting characteristics can be improved.

The superconductor layer of the present invention comprises a thin film formed on the tape-shaped substrate 2, and the crystals of the superconductor are oriented to form a superconducting wire.

[0036]

EXAMPLES The present invention will be described below based on examples.

Example 1 Step 1 As a superconductor material, Bi ₂ O ₃ , SrCO ₃ and CaC were used.
O ₃ and CuO were mixed at a molar ratio of 2: 2: 1: 2, and 81
The process of calcination and crushing for 12 hours at 0 ° C. was repeated twice.
It was confirmed from XRD that this powder had a Bi-2212 phase.

Step 2 The above powder was dispersed in a trichlorethylene solution containing polyvinyl butyral as a binder, and a masking tape was attached to one side of the solution to a thickness of 30 μm and a width of 20 mm.
× Immerse the base material 2 made of a silver tape having a length of 5 m, and
The substrate 2 was moved at a speed of a minute to deposit and form a 100 μm thick superconductor film, and then the masking tape was removed.

Step 3 Heat treatment was performed at 900 ° C. for 5 hours to form a NiO oxide film, and the thickness of N was 10 μm × width 20 mm × length 5 m.
A composite superconducting tape was produced by adhering, on both surfaces of the base material 1 made of i-tape, the silver tape base material 2 on which the superconducting film was adhered with a silver paste.

Step 4 The composite superconducting tape described above is wound into a size of about 10 mm inner diameter × about 100 mm outer diameter with a polytetrafluoroethylene (PTFE) sheet having a thickness of 100 μm sandwiched between the superconducting film surfaces. After drying at 150 ℃ for 30 minutes, PTFE
The sheet was removed to obtain a molded composite superconductor tape.

Step 5 The molded composite superconducting tape is heat treated (50
The temperature was raised from 0 ° C. to 885 ° C. over 1.5 hours, held at 885 ° C. for 10 minutes, cooled down to 835 ° C. over 5 hours, held for 1 hour, and then cooled down to room temperature in 3 hours) to obtain Bi-2212 superconductivity. A wire rod was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Bi-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 2 Step 1 As a superconductor material, Bi ₂ O ₃ , SrCO ₃ and CaC were used.
O ₃ and CuO were mixed at a molar ratio of 2: 2: 2: 3, and 81
The process of calcination and crushing for 12 hours at 0 ° C. was repeated twice.
It was confirmed from XRD that this powder had a Bi-2223 phase.

Steps 2, 3 and 4 A molded composite superconductor tape was prepared in the same manner as in Example 1.

Step 5 The molded composite superconducting tape was heat-treated (argon 8%).
(Heated in oxygen at 835 ° C for 100 hours) to give Bi-22
23 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was Bi-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 3 Step 1 As a superconductor material, (BaCO ₃ or SrCO ₃ ),
Mix CaCO ₃ and CuO in a molar ratio of 2: 1: 2,
The process of calcination and crushing for 12 hours at 40 ° C. was repeated twice.

Step 2 In the same manner as in Step 2 of Example 1, thickness 30 μm × width 20
10 mm thick on the base material 2 made of silver tape of 5 mm length x 5 mm
A μm superconductor was deposited.

Steps 3 and 4 A molded composite superconductor tape was prepared in the same manner as in Example 1.

Step 5 The molded composite superconducting tape is heat-treated (heated at 820 ° C. for 10 hours in pure oxygen while supplying Tl vapor) to obtain T.
The 1-222 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the T1-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 4 Step 1 As a superconductor material, (BaCO ₃ or SrCO ₃ ),
CaCO ₃ and CuO were mixed in a molar ratio of 2: 2: 3, and 8
The process of calcination at 40 ° C. for 12 hours and crushing was repeated twice.

Steps 2, 3 and 4 A molded composite superconductor tape was prepared in the same manner as in Example 3.

Step 5 The molded composite superconductor tape is heat-treated (heated in pure oxygen at 850 ° C. for 10 hours while supplying Tl vapor) to give T.
A 1-222 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Tl-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

[Example 5] Steps 1 to 4 The same procedure as in Example 4 was carried out to produce a molded composite superconductor tape.

Step 5 The molded composite superconductor tape was heat-treated (heated in pure oxygen at 850 ° C. for 10 hours while supplying Tl vapor and Pb vapor) to prepare a T-1223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Tl-1223 phase, the (00n) diffraction peak was strong, and was oriented along the c-axis.

Example 6 Step 1 Y: Ba: Cu was mixed at a molar ratio of 1: 2: 3 and dissolved in a mixed solvent of acetylacetonate, pyridine and propionic acid, and most of the solvent was evaporated with an evaporator. The residue was removed to give a methanol solution.

Step 2 The above methanol solution is applied by dipping onto a base material 2 made of a silver tape having a thickness of 30 μm × a width of 20 mm × a length of 5 m, which has a masking tape attached on one side, and then heated in air to 500 ° C. in 25 minutes. The above step was repeated until a precursor having a film thickness of 2 to 3 μm could be formed on the base material 2, and then the masking tape was removed.

Steps 3 and 4 A molded composite superconductor tape was produced in the same manner as in Steps 3 and 4 of Example 1.

Step 5 An oxygen partial pressure of 2 × 10 ^{4 was applied} to the above-mentioned molded composite superconductor tape.
After heat treatment at 770 ° C for 20 hours in an atmosphere of atm, heat treatment at 770 ° C for 0.5 hour in pure oxygen,
The temperature was lowered to room temperature over 2.5 hours to produce a Y-123 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Y-123 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 7 Step 1 Bi: Sr: Ca: Cu was mixed at a molar ratio of 2: 2: 1: 2, dissolved in a mixed solvent of acetylacetonate, pyridine and propionic acid, and then evaporated with an evaporator. Most of the solvent was removed and the residue was made into a methanol solution.

Steps 2-4 A molded composite superconductor tape was produced in the same manner as in Steps 2-4 of Example 6.

Step 5 An oxygen partial pressure of 2 × 10 ^{4 was applied} to the above-mentioned molded composite superconductor tape.
After performing a heat treatment at 770 ° C for 20 hours in an atmosphere of atm, raise the temperature from 500 ° C to 885 ° C in the atmosphere for 1.5 hours, hold at 885 ° C for 10 minutes, lower the temperature to 835 ° C in 5 hours, 1 After holding for 2 hours, the temperature is lowered to room temperature in 3 hours.
-21212 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Bi-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

[Example 8] Step 1 Bi: Sr: Ca: Cu were mixed at a molar ratio of 2: 2: 2: 3, and a methanol solution was obtained in the same manner as in Step 1 of Example 7.

Steps 2-4 A molded composite superconductor tape was produced in the same manner as in Steps 2-4 of Example 6.

Step 5 An oxygen partial pressure of 2 × 10 ^{4 was applied} to the above-mentioned molded composite superconductor tape.
After performing heat treatment at 770 ° C. for 20 hours in an atmosphere of atm, heating was performed in argon 8% oxygen at 835 ° C. for 100 hours to produce a Bi-2223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was Bi-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 9 Step 1 Ba, Ca and Cu metal naphthenates were mixed with Ba: Ca: C.
It was mixed at a molar ratio of u of 2: 1: 2 to prepare a toluene solution.

Steps 2-4 A molded composite superconductor tape was produced in the same manner as steps 2-4 of Example 6.

Step 5 The above-mentioned molded composite superconductor tape was heat-treated (heating in pure oxygen at 820 ° C. for 10 hours while supplying Tl vapor),
A T1-2212 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the T1-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 10 Step 1 Ba, Ca and Cu metal naphthenates were mixed with Ba: Ca: C.
It was mixed at a molar ratio of u of 2: 2: 2 to prepare a toluene solution.

Steps 2-4 A molded composite superconductor tape was produced in the same manner as in Steps 2-4 of Example 6.

Step 5 The molded composite superconductor tape is heat-treated (heating in pure oxygen at 850 ° C. for 10 hours while supplying Tl vapor),
A Tl-2223 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Tl-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 11 Step 1 Ba, Ca, Cu metal naphthenate was added to Ba: Ca: C.
It was mixed at a molar ratio of u of 2: 2: 3 to prepare a toluene solution.

Steps 2-4 A molded composite superconductor tape was produced in the same manner as steps 2-4 of Example 6.

Step 5 The molded composite superconductor tape was heat-treated (heating in pure oxygen at 850 ° C. for 30 hours while supplying Tl vapor and Pb vapor) to produce a T-1223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the T1-1223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 12 Step 1 Ba (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ and Cu (NO ₂ ) ₂ nitrates have a Ba: Ca: Cu atomic ratio of 2: 2: 3. Were weighed to prepare an aqueous solution of 0.05 mol / l.

Step 2 The aqueous solution was made into droplets having a diameter of several μm by an ultrasonic oscillator, and heated to 600 ° C. by a heater, and the thickness was 30 μm × width 20
It was sprayed onto a silver tape-shaped substrate 2 having a length of mm × 5 m. At this time, the substrate 2 was moved at a speed of 10 mm / hour for continuous film formation to form a precursor film of about 5 μm.

Step 3 A composite tape-shaped substrate was produced in the same manner as in Step 3 of Example 1.

Step 4 The composite tape-shaped substrate wound around an alumina bobbin is heat-treated (850 850 in pure oxygen while supplying Tl vapor).
(Temperature heating for 10 hours) to produce a Tl-1223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Tl-1223 phase, the (00n) diffraction peak was strong, and the crystals were c-axis oriented.

[Example 13] Steps 1 to 3 In the same manner as Steps 1 to 3 of Example 12, a composite tape-shaped substrate was produced.

Step 4 The composite tape-shaped substrate wound around an alumina bobbin is heat treated (830 in pure oxygen while supplying Tl vapor).
(Heating at 10 ° C. for 10 hours) to produce a Tl-2223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the Tl-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

[Example 14] Step 1 Ba (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ and Cu (NO ₂ ) ₂ nitrates were used, and the atomic ratio of Ba: Ca: Cu was 2: 1: 2. Were weighed to prepare an aqueous solution of 0.05 mol / l.

Steps 2 and 3 In the same manner as steps 2 and 3 of Example 12, a composite tape-shaped substrate was produced.

Step 4 The composite tape-shaped substrate wound around an alumina bobbin is heat treated (850 in pure oxygen while supplying Tl vapor).
(Heating at 10 ° C. for 10 hours) to produce a T1-2212 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was the T1-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 15 Step 1 Bi (NO ₂ ) ₃ , Sr (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ , Cu (N
O ₂ ) ₂ nitrate was weighed so that the atomic ratio of Bi: Sr: Ca: Cu was 2: 2: 1: 2, and 0.05 mol /
An aqueous solution of 1 was prepared.

Steps 2 and 3 In the same manner as Steps 2 and 3 of Example 12, a composite tape-shaped substrate was produced.

Step 4 The composite tape-shaped substrate wound around an alumina bobbin was heat-treated (the temperature was raised from 500 ° C. to 885 ° C. in 1.5 hours in the air, held at 885 ° C. for 10 minutes, and maintained at 835 ° C. for 5 hours). After cooling down to room temperature for 1 hour, lowering to room temperature in 3 hours), B
An i-2212 superconducting wire was produced.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was Bi-2212 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

Example 16 Step 1 Bi (NO ₂ ) ₃ , Sr (NO ₂ ) ₂ , Ca (NO ₂ ) ₂ , Cu (N
The nitrate of O ₂ ) ₂ was weighed so that the atomic ratio of Bi: Sr: Ca: Cu was 2: 2: 2: 3, and 0.05 mol /
An aqueous solution of 1 was prepared.

Steps 2 and 3 In the same manner as Steps 2 and 3 of Example 12, a composite tape-shaped substrate was produced.

Step 4 The composite tape-shaped substrate wound around an alumina bobbin was heat-treated (heated in argon 8% oxygen at 835 ° C. for 100 hours) to prepare a Bi-2223 superconducting wire.

As a result of XRD analysis, it was confirmed that the main crystal phase of the superconductor was Bi-2223 phase, the (00n) diffraction peak was strong, and the crystal was c-axis oriented.

[Example 17] Oxide-d containing MgO or the like in place of the base material 2 of the silver tape used in each of the above Examples.
Base material 2 made of isprsive-alloy Ag-Mg alloy tape
Using, the composite superconducting wire was produced in the same manner. As a result, it was possible to obtain the same characteristics and higher mechanical strength.

Further, a plurality of composite superconducting wires prepared in the above-mentioned respective examples were combined, then wound, tightened, impregnated with epoxy resin and cured to prepare a superconducting coil. The critical current density of the superconducting coil was the same as the critical current density of the composite tape-shaped wire material of the present invention shown in Table 1, and all showed excellent characteristics.

[0106]

EFFECTS OF THE INVENTION The composite superconducting wire of the present invention has a structure in which the front and back of the base material are sandwiched by superconducting layers made of the same constituent material, so that the difference in thermal expansion coefficient between the base material and the superconducting layer It is possible to provide a material having excellent superconducting properties, which is less likely to warp or deform due to cracks, which can prevent cracks from occurring in the superconducting layer.

Therefore, it is possible to provide a superconducting device such as a superconducting wire or a superconducting magnet having a high critical current density which is cooled and operated by liquid nitrogen in a magnetic field.

Further, since the superconducting equipment using the composite superconducting wire of the present invention can be cooled and operated by liquid nitrogen,
The cooling system, heat insulation structure, etc. can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a superconducting wire according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of a superconducting wire according to another embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing an example of an apparatus for manufacturing a superconducting wire according to the present invention by a dip coating method.

FIG. 4 is a schematic configuration diagram showing an example of an apparatus for manufacturing a superconducting wire according to the present invention by a spray pyrolysis method.

[Explanation of symbols]

1 ... Base material 1 (metal or ceramics), 2 ... Base material 2
(Silver or silver alloy), 3 ... Superconductor layer, 4 ... Substrate 1 delivery spool, 5 ... Substrate 2 delivery spool, 6 ... Reel, 7 ... Composite tape substrate, 8 ... Composite tape substrate winding Spool, 9 ... Heater, 10 ... Film thickness detection device, 11
... Drying system, 12 ... Stirrer, 13 ... Viscometer, 14 ... Masking tape, 15 ... Masking tape take-up reel, 1
6 ... Slurry, 17 ... Raw material tank, 18 ... Mist, 19
... atomizer, 20 ... ultrasonic transducer, 21 ... carrier gas supply port, 22 ... carrier gas exhaust port.

Claims (7)

[Claims] 1. An oxide superconducting wire, characterized in that an oxide superconducting layer is formed on at least both front and back surfaces of a base material made of metal or ceramics with a silver or silver alloy layer interposed therebetween. 2. The base material is Al, Ni, Cu—Al alloy, NiO, Al ₂ O ₃ , YSZ, SrTiO ₃ , Mg.
The oxide superconducting wire according to claim 1, which is composed of either O or ZrO. 3. The oxide superconducting wire according to claim 1, wherein the oxide superconductor layer is an oxide superconductor in which c-axes of crystals are aligned in the same direction. 4. A step of forming an oxide superconductor material (or a raw material thereof) on a tape-shaped base material made of silver or a silver alloy, and the oxide superconductor material on at least both front and back surfaces of the base material made of metal or ceramics. A method for producing an oxide superconducting wire, comprising: a step of laminating a tape-shaped base material on which is formed to form a composite; and a step of firing the composite material to make the oxide superconducting material a superconductor. 5. The oxide superconductor material (or its raw material) when forming the oxide superconductor material (or its raw material) on the tape-shaped substrate made of the silver or silver alloy.
Immersed in a liquid dissolved or dispersed in a solvent, or
The method for producing an oxide superconducting wire according to claim 4, wherein the liquid is atomized and deposited on a tape-shaped substrate. 6. A superconducting wire comprising an oxide superconducting wire formed by winding an oxide superconducting layer with a silver or silver alloy layer interposed between at least both front and back surfaces of a base material made of metal or ceramics. coil. 7. A laminate of a plurality of layers obtained by winding an oxide superconducting wire having an oxide superconducting layer formed with a silver or silver alloy layer on at least both front and back surfaces of a base material made of metal or ceramics. A superconducting magnet having a coil formed by