JPH0567517A - Manufacture of superconducting oxide coil - Google Patents

Abstract

PURPOSE:To manufacture a high-performance superconducting coil by winding a superconducting wire formed of an oxide superconducting thin film around a take-up reel in the chamber of a thin film forming means together with tapes of a stabilizing and insulating materials. CONSTITUTION:This oxide superconducting coil 15 is manufactured by using a long superconducting wire 6 constituted of a superconducting oxide thin film formed on the surface of a long substrate 5 by means of a thin film forming means of a sputtering, MBE, or reactive vapor-deposition method. At the time of manufacturing the coil 15, the coil 15 is formed by winding the wire 6 with the oxide superconducting thin film around a take-up reel 4 in the chamber 2 of the thin film forming means together with a tape 7 of a stabilizing material and another tape 8 of an insulating material. It is also possible, in addition, to simultaneously wind the tape 9 of a low-boiling point metal with the tapes 7 and 8.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the field of energy production such as nuclear fusion power generation and MHD power generation, superconducting coils for power storage, transportation means such as linear motor cars and electromagnetic propulsion vessels, and M
The present invention relates to an oxide superconducting coil used in medical fields such as RI.

[0002]

2. Description of the Related Art In recent years, oxide superconductors having a critical temperature (Tc) higher than the liquid nitrogen temperature (about 77 K) have been used, for example, Y-Ba-Cu-O system and Bi-Sr-Ca-Cu-O system.
System, oxide superconductors such as Tl-Ba-Ca-Cu-O system have been discovered. In order to apply these oxide superconductors to various superconducting devices such as electric power transportation, superconducting magnets, and superconducting devices, various researches have been conducted toward the practical application of wire oxides or coils of oxide superconductors. ing.

One of the methods for producing such an oxide superconductor
As a method, a thin film forming means such as a sputtering method, an MBE method (molecular beam epitaxy method), or a reactive vapor deposition method may be used directly or through an intermediate layer on the surface of a substrate such as a metal substrate (Hastelloy, stainless steel, etc.) or a ceramic substrate. A method of forming an oxide superconducting thin film is known. The oxide superconducting thin film thus formed by the thin film forming means is attracting attention as a practical manufacturing method because it has a large critical current density (Jc) and a material having excellent superconducting properties can be obtained.

[0004]

To manufacture a superconducting tape using the above-mentioned thin film forming means, an oxide superconducting thin film is formed while moving a long tape, and the tape after the film formation is once reeled. It is wound on to obtain a long superconducting tape. At this time, since the tape after film formation is wound up, bending strain is applied to the superconducting thin film. Even if the bending strain is about 0.1%, the deterioration of the superconducting property is observed. Therefore, it is usual to design the diameter of the take-up reel so that the bending strain is as low as possible. Further, when a coil is produced using such a superconducting tape, a stabilizing material (silver, copper, etc.) or an insulating material is added in a separate line, and the coil is wound together with the superconducting tape on a coil winding machine. In this case, many bending strains are applied to the superconducting thin film such as bending-straight-bending-, and there is a problem that the superconducting characteristics are significantly deteriorated when the coil is formed. The present invention has been made in view of the above circumstances, and provides a method for producing an oxide superconductor capable of producing a high-performance superconducting coil while minimizing the performance deterioration of the superconducting thin film due to bending strain. Has an aim.

[0005]

The present invention is directed to a long superconducting film in which an oxide superconducting thin film is formed on the surface of a long base material by a thin film forming means selected from a sputtering method, an MBE method and a reactive vapor deposition method. A method for manufacturing an oxide superconducting coil using a wire, comprising: winding a superconducting wire having an oxide superconducting thin film formed on it in a chamber of the thin film forming means, and winding the superconducting wire on the reel. The above problem was solved by winding the stabilizing material tape and the insulating material tape at the same time to form a coil.

Further, when the superconducting wire is wound around the reel, the stabilizer tape, the insulating tape and the low melting point metal tape can be wound at the same time. Further, after winding the wire rod and the tape around the reel, it may be heat-treated.

[0007]

[Operation] In the chamber, the superconducting wire on which the oxide superconducting thin film is formed is wound on the take-up reel, and when the superconducting wire is wound on the reel, the stabilizer tape and the insulating tape are simultaneously wound. Since the coil is formed in this manner, the number of windings is only one and the bending strain applied to the superconducting thin film can be minimized.

[0008]

1 shows an example of a manufacturing apparatus suitably used for a method for manufacturing an oxide superconducting coil according to the present invention. In the figure, reference numeral 1 is a vapor deposition portion of thin film forming means, 2 is a chamber, and 3 is a chamber. Is a supply reel for supplying a substrate, 4 is a take-up reel, 5
Is a base tape, 6 is a superconducting tape on which an oxide superconducting thin film is formed, 7 is a stabilizer tape, 8 is an insulating tape, 9 is a low melting metal tape, 10, 11 and 12 are supply reels, 13
Is a heater.

As the thin film forming means, a sputtering method, an MBE method (molecular beam epitaxy method),
A reactive vapor deposition method or the like is used. When the sputtering method is used as the thin film forming means, the vapor deposition section 1 of the thin film forming means is a target made of an oxide superconductor such as a Y—Ba—Cu—O superconductor or a precursor thereof, and MB
The E method is a plurality of molecular beam sources for respectively heating and evaporating a compound of a metal element (oxide or the like) forming the oxide superconductor, and in the case of the reactive vapor deposition method, forming an oxide superconductor. A configuration including a plurality of cells that heat-deposit metal elements may be used.

The material of the base tape 5 is Hastelloy,
Metals such as stainless steel are used. Further, as the material of the stabilizer tape 7, silver, silver alloy, gold or the like having good conductivity is preferably used. Further, as the material of the insulating tape 8, a material containing an insulating material such as polyimide is preferably used.
Further, as the material of the low melting point metal tape 9, (lead-tin) solder or a commercially available low melting point solder for ceramics (for example, Cerasolzer W) is preferably used.

In order to manufacture a superconducting coil using this manufacturing apparatus, the tip of the base tape 5 is wound around the take-up reel 4 in the chamber 2, and the stabilizer tape 7, the insulating tape 8 and the low melting point metal are used. Wrap tape 9 around. Then, the inside of the chamber 2 is made into an atmosphere suitable for vapor deposition, such as vacuum or reduced pressure, and the heater 13 is used to make the base tape 5
To start heating. Then, the winding reel is rotated to start winding each tape, and the fine particles 14 of the oxide superconductor are scattered from the vapor deposition section 1 to form an oxide superconducting thin film on the base tape 5. The superconducting tape 6 on which the oxide superconducting thin film is formed is wound on the take-up reel 4 together with the stabilizer tape 7, the insulating tape 8 and the low melting point metal tape 9. In this way, the superconducting tape 6 is attached to the take-up reel 4.
By winding each of the other tapes 7, 8 and 9,
The take-up reel itself can be the superconducting coil 15.

The superconducting coil 15 thus obtained
May be subjected to heat treatment thereafter. By this heat treatment, the low-melting-point metal tape 9 is melted and is cooled and solidified, so that the entire composite can be achieved. Further, when the low melting point metal is heated and melted, the entire coil may be connected to an ultrasonic oscillator to promote the joining of the superconducting thin film and the stabilizing material.

According to this method of manufacturing a superconducting coil, it is possible to form the superconducting tape 6 and form it into a coil shape at the same time. Therefore, the number of times of experience of bending strain of the oxide superconducting thin film should be at least one. It is possible to minimize the performance deterioration of the oxide superconducting thin film due to bending strain.

At the same time when the superconducting tape 7 is wound up,
Since the stabilizer tape 7 and the insulating tape 8 are wound, it is possible to form a coil simultaneously with vapor deposition. Further, the low-melting-point metal tape 9 can be rolled up into a coil and then heat-treated to metal-bond the superconducting layer and the stabilizing material.

In the example described above, the single pancake coil is manufactured with the position of the take-up reel 4 fixed, but the solenoid coil can be manufactured by axially moving the take-up reel. is there. Also, FIG.
As shown in FIG. 1, an insulating tape 1 having grooves 16 formed in the width direction
7 is used, a coil 19 having a large number of holes 18 for passing a refrigerant and having a high cooling efficiency is formed as shown in FIG.
Can also be formed.

(Production Example 1) A Y-Ba-Cu-O superconducting coil was produced using an RF magnetron sputtering device. Hastelloy C-276 tape (0.1 mm thick,
Yttria-stabilized zirconia (YSZ) on (5 mm width)
Was vapor-deposited to a thickness of 0.5 μm, and Y-Ba-Cu-was deposited on it using a sintered body target in which the raw material composition was adjusted so that the film composition after sputtering would match Y ₁ Ba ₂ Cu ₃ O _7-x. An O superconductor was sputtered to a thickness of 1.0 μm. As the sputtering conditions, the sputtering gas was Ar / O ₂ = 1: 10, the chamber internal pressure was 10 ⁻² Torr, the RF power was 150 W, and the substrate temperature was 640 ° C. The tape used at this time had a length of several tens of meters, and sputtering was performed with a mechanism that moved on a heater facing the target at a speed of 400 mm / hour.
As shown in FIG. 2, the tape to be sent out has a first portion 20 (the vapor deposition portion may not be superconducting), current terminal portions 21 and 22, a coil conductor portion 23, and a final coil fixing portion 24, depending on the length of the tape. It is configured to have. Also, on the winding side,
A stainless steel 200 mm diameter reel (inner diameter 180 mm) having a 1.0 mm thick silver sheet bonded to the surface was placed. Also, low melting point metal tape (0.2 mm thick) and silver tape (0.5 m) supplied from another reel placed in the chamber.
m thickness) and insulating Kapton tape (30 μm thickness) are simultaneously wound to form a 280 mm diameter coil.
Heat treatment was performed in an atmosphere of 5 ° C. to obtain an integrated single pancake coil. Y-Ba-Cu-of the obtained coil
The Tc of the O superconductor was 85K.

(Production Example 2) Using an RF magnetron sputtering device, (Bi, Pb) -Sr-Ca-Cu-
An O (BSCCO) superconducting coil was produced. SUS30
A tens of meters of a composite tape prepared by coating 30 μm thick silver with 4 stainless steel tape (0.1 mm thickness, 5 mm width) was prepared as a base material for RF sputtering. Bi ₇ Pb ₁ Sr ₆ Ca ₃ Cu ₁₂ Oz as a single target
A sintered body was prepared according to the above composition and sputtered under the following conditions to obtain a high temperature phase of BSCCO (2223 type). At this time, the sputtering condition is that the chamber pressure is 3
0 mTorr (pure Ar), RF power 100 W, and film formation rate 3 nm / min. Films are continuously formed on the composite tape, and at the same time, silver tape, quartz tape (30 μm
(Thickness) to form a coil. After this 845 ℃,
Heat treatment was performed for 10 hours to obtain a single pancake coil.

(Production Example 3) Using a reactive vapor deposition apparatus, Y-B
An a-Cu-O superconducting coil was produced. Hastelloy C-
Yttria-stabilized zirconia (YSZ) was vapor-deposited to a thickness of 0.5 μm on 276 tape (0.1 mm thickness, 5 mm width),
It was used as a substrate for reactive vapor deposition. Each of Y, Ba, and Cu metals is dissolved and evaporated in the cell, and about 2 μm in an oxidizing atmosphere.
A thick Y-Ba-Cu-O film was formed. The maximum temperature of the cell was around 1800 ° C. At this time, an oxygen plasma was generated by an RF coil to accelerate oxidation, and a high-characteristic superconducting film was formed. The conditions at this time are that the metal evaporation sources are Y and B.
a, Cu, substrate temperature 650 ° C., oxygen pressure 2 × 10 ⁻⁴
Torr and RF power were 120W. Then, it was coiled in the same manner as in Production Example 1 to obtain a single pancake coil.

(Production Example 4) Using a MBE apparatus, Bi-S
An r-Ca-Cu-O (BSCCO) superconducting coil was produced. SUS304 stainless steel tape (0.1 mm thick,
A composite tape having a thickness of 5 mm and coated with silver by a vapor deposition method to a thickness of 30 μm was prepared for several tens of meters and used as a base material for MBE.
Bi ₂ O ₃ and SrO were deposited by electron beam heating, and Cu and Ca were deposited by cell heating. The pressure in the chamber is 10 ⁻⁵ to 10 ⁻⁶ Torr, and film formation is continuously performed on the composite tape, and at the same time, silver tape, quartz tape (3
(0 μm thickness) was wound into a coil shape. After this, 8
Heat treatment was performed at 45 ° C. for 10 hours to obtain a single pancake coil.

[0020]

As described above, the manufacturing method of the oxide superconducting coil of the present invention is the sputtering method, the MBE method.
It is possible to form an oxide superconducting thin film on a base material by either method of forming a superconducting wire and forming a superconducting wire at the same time as forming a coil shape. The number of times of strain experience can be set to a minimum of 1, and the deterioration of performance of the oxide superconducting thin film due to bending strain can be minimized.

Further, since the stabilizing material and the insulating material are wound at the same time that the superconducting wire is wound, the coil can be formed at the same time as vapor deposition in the chamber. Further, the low-melting-point metal tape can be rolled up into a coil and then heat-treated to metal-bond the superconducting layer and the stabilizing material.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an example of a manufacturing apparatus suitable for a method for manufacturing an oxide superconducting coil of the present invention.

FIG. 2 is a side view showing an example of a superconducting tape manufactured in a manufacturing example.

FIG. 3 is a perspective view showing an insulating tape provided with grooves as an application example of the present invention.

FIG. 4 is a perspective view showing a coil manufactured by using the insulating tape of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Vapor deposition part of thin film forming means, 2 ... Chamber, 3 ... Supply reel, 4 ... Winding reel, 5 ... Base material tape, 6 ... Superconducting tape, 7 ... Stabilizing material tape, 8 ... Insulating tape, 9 ... Low Melting point metal tape, 10, 11, 12 ... Supply reel, 13 ...
Heater, 14 ... Fine particles of oxide superconductor, 15 ... Superconducting coil

Claims (3)

[Claims] 1. An oxide superconducting coil using a long superconducting wire in which an oxide superconducting thin film is formed on the surface of a long base material by a thin film forming means selected from a sputtering method, an MBE method, and a reactive vapor deposition method. The method of manufacturing a thin film forming means, wherein the superconducting wire having an oxide superconducting thin film formed thereon is wound on a take-up reel, and a stabilizer tape is used when the superconducting wire is wound on the reel. A method for manufacturing an oxide superconducting coil, characterized in that a coil is formed by simultaneously winding and an insulating tape. 2. When winding a superconducting wire on the reel,
The method for producing an oxide superconducting coil according to claim 1, wherein the stabilizing material tape, the insulating material tape, and the low melting point metal tape are wound at the same time. 3. The oxide superconducting coil according to claim 2, wherein the wire rod and the stabilizing material tape, the insulating material tape and the low melting point metal tape are simultaneously wound on the reel and then heat treated. Production method.