JP2014002833A - Oxide superconducting wire and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconducting wire in which entry of moisture into an oxide superconducting layer can be suppressed, and a method of manufacturing an oxide superconducting wire, capable of easily manufacturing the superconducting wire.SOLUTION: The oxide superconducting wire of the present invention includes an oxide superconducting laminate 5 constituted of: a substrate 1; an intermediate layer 2 and an oxide superconducting layer 3 which are provided on the substrate 1; and a stabilization base layer 4 of Ag provided on the oxide superconducting layer 3. The peripheral surface side of the oxide superconducting laminate 5 is covered with a first solder layer 6 and a first stabilization layer 7 formed by winding a metal tape in this order, so that the entire peripheral surface is covered.

Description

  The present invention relates to a long oxide superconducting wire whose application and development are being applied to a superconducting power cable, a superconducting magnet, a superconducting energy storage device, a superconducting power generation device, a medical MRI apparatus, a superconducting current lead, and the like. About.

RE-123 oxide superconductor discovered in recent years (REBa ₂ Cu ₃ O _{7-X, where} RE is a rare earth element including Y) exhibits superconductivity above liquid nitrogen temperature and has low current loss. It is considered as a very promising material for practical use, and it is desired to process it into a wire and use it as a power supply conductor or a magnetic coil. As a method for processing this oxide superconductor into a wire, a metal having high strength, heat resistance, and easy to process into a wire is processed into a long tape shape, and this metal base tape is Methods for forming oxide superconducting layers have been studied.

  Furthermore, since the oxide superconductor has electrical anisotropy, it is necessary to control crystal orientation when forming an oxide superconducting layer on the substrate. A technique is known in which an oxide superconducting layer is stacked on an intermediate layer. As an example of a technique using this intermediate layer, an ion beam assisted deposition (IBAD method) is known, and this method uses constituent particles struck from a target by a sputtering method on a substrate. It is known as a method of depositing an intermediate layer while irradiating argon ions generated from an ion gun or the like simultaneously from an oblique direction (for example, 45 ° direction). According to this IBAD method, an intermediate layer exhibiting high biaxial orientation can be formed on a base material. Therefore, by forming an oxide superconducting thin film on this intermediate layer, an oxide superconducting conductor having excellent superconducting properties. Can be obtained.

In the oxide superconducting conductor, a thin silver stabilizing layer is formed on the oxide superconducting layer, and a thick stabilizing layer made of a highly conductive metal material such as copper is provided thereon. The structure which laminates | stacks these stabilization layers is employ | adopted (for example, refer patent document 1).
The Ag stabilizing layer is also provided for the purpose of adjusting fluctuations in the amount of oxygen when the oxide superconducting layer is subjected to oxygen heat treatment, and the Cu stabilizing layer is formed from the superconducting state of the oxide superconducting layer. It is provided for the purpose of functioning as a bypass for commutating the current in the oxide superconducting layer when attempting to transition to the normal conducting state.

  In addition, a structure is known in which an oxide superconducting conductor is sandwiched between metal tapes, and the metal tape is filled and joined with a joining member such as solder (see Patent Documents 2 to 4).

Japanese Unexamined Patent Publication No. 7-73758 Special table 2003-505848 gazette JP 2008-243588 A Special table 2009-544144

  Cu used as a stabilization layer is usually 20 μm to 150 μm in order to function as a bypass for commutating the current of the oxide superconducting layer when the oxide superconducting layer attempts to transition from the superconducting state to the normal conducting state. Thickness is required. The thickness of the Cu stabilization layer differs depending on the operating temperature of the superconducting wire, the current flowing in the superconducting wire, the detection system when a quench (normal conducting transition) occurs, and the like. As a method for forming a thin Cu stabilization layer, a plating method or the like is known. However, since plating is a crystal growth using electrolysis, the process takes time, and in the case of forming a thick Cu stabilization layer, There is a problem with productivity.

FIG. 4 is a schematic view showing a configuration example of a conventional oxide superconducting conductor. An oxide superconducting conductor 200 shown in FIG. 4 includes an intermediate layer 202 formed on an elongated base material 201 such as Hastelloy tape by an IBAD method, and REBa ₂ Cu ₃ O _7-X (RE is Y). An oxide superconducting layer 203 made of an oxide superconductor made of a rare earth element) and a highly conductive stabilizing layer 204 are sequentially laminated. However, in the oxide superconducting conductor 200 having such a configuration, since the side surface of the superconducting layer 203 that is easily damaged by moisture is exposed to the outside, the superconducting characteristics are deteriorated by moisture entering during the manufacturing process. There is a risk of causing it.

  In the techniques described in Patent Documents 2 to 4, since the oxide superconducting conductor is encapsulated by a solder fillet or the like, the side surface of the oxide superconducting layer is not exposed to the outside. In FIG. 5, the schematic block diagram of the oxide superconducting wire 300 of such a structure is shown. The oxide superconducting wire 300 shown in FIG. 5 includes an oxide superconducting conductor 301 sandwiched between metal tapes 302 and 302 such as Cu, and a Sn alloy solder 303 is filled between the metal tapes 302. Yes. At the end of the oxide superconducting wire 300 having such a configuration, the metal tape 302 such as Cu and the Sn alloy solder 303 containing Pb are present on the same surface, and the side surface of the wire including the metal tape 302 and the solder 303 is present. When a water droplet W adheres to the surface, a battery is formed by the Cu of the metal tape 302 and the Sn of the solder 303 via the water droplet W, and the Sn of the solder 303 is dissolved into the water droplet W, and the solder 303 is preferentially corroded. May end up. Therefore, even such a method of encapsulating the oxide superconductor with a solder fillet or the like is not sufficient as a method of protecting the oxide superconductor from moisture.

  The present invention has been made in view of the above-described conventional situation, and an oxide superconducting wire capable of suppressing the ingress of moisture into the oxide superconducting layer, and the oxide superconducting capable of easily producing the superconducting wire. It aims at providing the manufacturing method of a wire.

In order to solve the above problems, the present invention has the following configuration.
The oxide superconducting wire of the present invention comprises a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer. A superconductor laminate, and a first solder layer and a first stabilization layer formed by winding a metal tape so as to cover the entire circumference on the circumference of the oxide superconductor laminate. These are coated in this order.
In the oxide superconducting wire of the present invention, a second solder layer and a metal tape are wound around the peripheral surface side of the first stabilization layer so as to cover the entire outer peripheral surface of the first stabilization layer. It is preferable that the formed second stabilizing layer is coated in this order.
In the oxide superconducting wire of the present invention, the first stabilizing layer formed by winding the metal tape, between the ends in the width direction of the metal tape of each turn adjacent to the longitudinal direction of the oxide superconducting laminate. It is also preferable that the second stabilizing layer is formed by winding a metal tape so as to cover the contact portion.

The method for producing an oxide superconducting wire according to the present invention comprises: a base material; an intermediate layer provided on the base material; an oxide superconducting layer; and an Ag stabilizing base layer provided on the oxide superconducting layer. An oxide superconducting laminate is provided, and a first solder layer and a first stabilizing layer formed of a metal tape are provided on the peripheral surface side of the oxide superconducting laminate so as to cover the entire peripheral surface. A method for producing an oxide superconducting wire coated in this order, wherein a first stabilizing layer tape having a first solder layer formed on at least one surface of a metal tape is formed on the oxide superconducting laminate. The first solder layer and the first solder layer are wound by butt wrap winding around the outer peripheral surface so that the widthwise ends of the stabilization layer tape of each turn adjacent to each other in the longitudinal direction of the oxide superconducting laminate are in contact with each other. A stabilization layer is formed.
In the method of manufacturing an oxide superconducting wire according to the present invention, a first stabilization layer tape having a first solder layer formed on one surface of a metal tape is wound on the outer peripheral surface of the oxide superconducting laminate by the butt wrap winding. After winding and forming the first solder layer and the first stabilization layer, the second stabilization layer tape having the second solder layer formed on one surface of the metal tape is used as the oxide superconducting laminate. Preferably, the second solder layer and the second stabilization layer are formed by wrapping the outer periphery of the first stabilization layer formed on the outer periphery of the first stabilization layer by the butt wrap winding.

In the method for manufacturing an oxide superconducting wire according to the present invention, a first stabilizing layer tape in which a first solder layer is formed on one surface of a metal tape and a second solder layer is formed on the other surface of the metal tape. Is wound around the outer peripheral surface of the oxide superconducting laminate by the butt wrap winding to form the first solder layer, the first stabilizing layer, and the second solder layer, and then a second stability made of a metal tape. Preferably, the second stabilizing layer is formed by winding a stratified tape around the outer peripheral surface of the second solder layer formed on the outer peripheral surface of the oxide superconducting laminate by the butt wrap winding.
In the method for producing an oxide superconducting wire according to the present invention, the first superconducting laminate may be configured to cover a contact portion between widthwise ends of the first stabilization layer tape of each turn adjacent to the longitudinal direction of the oxide superconducting laminate. It is also preferable to wrap the two-stabilized layer tape.

The oxide superconducting wire of the present invention has a configuration in which a first solder layer and a first stabilizing layer formed of a metal tape are covered in this order so as to cover the entire outer peripheral surface of the oxide superconducting laminate. It was. As a result, the oxide superconducting wire of the present invention has a configuration in which the entire circumference of the outermost periphery is covered with a stabilization layer made of a metal tape, so that the solder layer is corroded even when water droplets or the like adhere thereto. Intrusion of moisture into the oxide superconducting layer can be suppressed.
In the oxide superconducting wire of the present invention, the first solder layer, the first stabilizing layer, the second solder layer, and the second stabilizing layer are formed so as to cover the outer peripheral surface of the oxide superconducting laminate. If so, it is possible to realize a configuration in which all side surfaces of the oxide superconducting laminate including the oxide superconducting layer are shielded from the outside. With such a configuration, it is possible to prevent moisture from entering the oxide superconducting layer and prevent the oxide superconducting layer from being damaged by moisture and deteriorating superconducting characteristics.
Further, in the oxide superconducting wire of the present invention, the second stabilization layer is formed by winding the metal tape so as to cover the contact portion of each turn of the first stabilization layer formed by winding the metal tape. If it comprises, the hermetic property (airtightness) of an oxide superconducting wire can be improved, and it can suppress further that an oxide superconducting layer is damaged by a water | moisture content.

According to the oxide superconducting wire manufacturing method of the present invention, it is possible to provide an oxide superconducting wire that can prevent moisture in the oxide superconducting layer from entering. Moreover, the oxide superconducting wire production method of the present invention can produce an oxide superconducting wire more easily than the conventional method of forming a stabilization layer by plating. Furthermore, by adjusting the thickness of the metal tape, a stabilization layer having a desired thickness can be easily formed.
Further, in the method for manufacturing an oxide superconducting wire according to the present invention, a first stabilization in which a first solder layer is formed on one surface of a metal tape and a second solder layer is formed on the other surface of the metal tape. If the layer tape and the second stabilization layer tape made of the metal tape are wound around the oxide superconducting laminate in order, the first stabilization layer tape is manufactured by immersing the metal tape in the solder bath. Therefore, a simpler production method can be obtained.
Furthermore, in the method for manufacturing an oxide superconducting wire according to the present invention, the second stabilization layer tape is wound so as to cover the contact portion of the first stabilization layer tape at each turn adjacent to the longitudinal direction of the oxide superconducting laminate. If it is configured to be attached, it is possible to provide an oxide superconducting wire that has high hermeticity (air tightness) and can further prevent the oxide superconducting layer from being damaged by moisture.

FIG. 1A is a schematic cross-sectional view showing one embodiment of an oxide superconducting wire according to the present invention, and FIG. 1B is an oxide incorporated in the oxide superconducting wire shown in FIG. It is a schematic sectional drawing of a superconducting laminated body. It is process explanatory drawing for demonstrating the process of 1st Embodiment of the manufacturing method of the oxide superconducting wire which concerns on this invention. It is process explanatory drawing for demonstrating the process of 2nd Embodiment of the manufacturing method of the oxide superconducting wire which concerns on this invention. It is a schematic diagram which shows an example structure of the conventional oxide superconducting wire. It is a schematic diagram for demonstrating the mode of corrosion by a water | moisture content in the example structure of the conventional oxide superconducting wire.

Hereinafter, embodiments of an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 (a) is a schematic perspective view schematically showing one embodiment of an oxide superconducting wire according to the present invention, and FIG. 1 (b) is incorporated in the oxide superconducting wire shown in FIG. 1 (a). It is a schematic block diagram of the oxide superconducting laminated body.
An oxide superconducting laminate 5 shown in FIG. 1 (b) is formed by laminating an intermediate layer 2, an oxide superconducting layer 3 and a stabilizing base layer 4 on a long tape-like base material 1, and this oxide superconducting material. A laminated body 5 is provided at the center, and a first stabilization layer 7 made of a first solder layer 6 and a metal tape is formed so as to cover the entire circumferential surface thereof, and covers the entire circumferential surface of the first stabilization layer 7. A second stabilizing layer 9 made of a second solder layer 8 and a metal tape is formed on the substrate, and an oxide superconducting wire 10 is formed.

The substrate 1 may be any material that can be used as a substrate for ordinary superconducting wires, and is preferably in the form of a long plate, sheet, or tape, and is preferably made of a heat-resistant metal. Among heat resistant metals, an alloy is preferable, and a nickel (Ni) alloy or a copper (Cu) alloy is more preferable. Among them, if it is a commercial product, Hastelloy (trade name, manufactured by Haynes) is suitable, and the amount of components such as molybdenum (Mo), chromium (Cr), iron (Fe), cobalt (Co) is different, Hastelloy B, Any kind of C, G, N, W, etc. can be used.
What is necessary is just to adjust the thickness of the base material 1 suitably according to the objective, Usually, it is preferable that it is 10-500 micrometers, and it is more preferable that it is 20-200 micrometers. By setting the lower limit value or more, the strength can be further improved, and by setting the upper limit value or less, the critical current density of the overall can be further improved.

The intermediate layer 2 controls the crystal orientation of the oxide superconducting layer 3 and prevents diffusion of metal elements in the base material 1 into the oxide superconducting layer 3. Furthermore, it functions as a buffer layer that alleviates the difference in physical properties (thermal expansion coefficient, lattice constant, etc.) between the base material 1 and the oxide superconducting layer 3, and the material has physical properties that are different from those of the base material 1 and oxide. A metal oxide showing an intermediate value with the superconducting layer 3 is preferable. Specifically, preferred materials for the intermediate layer 2 are Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd _2. Examples thereof include metal oxides such as O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ .
The intermediate layer 2 may be a single layer or a plurality of layers. For example, the layer made of the metal oxide (metal oxide layer) preferably has crystal orientation, and when it is a plurality of layers, the outermost layer (layer closest to the superconducting layer 3) is at least It preferably has crystal orientation.

A bed layer may be interposed between the intermediate layer 2 and the substrate 1. The bed layer has high heat resistance and is used for reducing interfacial reactivity, and is used for obtaining the orientation of a film disposed thereon. Such a bed layer is arranged as necessary, and is made of, for example, yttria (Y ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), or the like. Is done. The bed layer is formed by a film forming method such as a sputtering method, and has a thickness of 10 to 200 nm, for example.

Furthermore, in this invention, it is good also as a structure where the diffusion prevention layer was interposed between the base material 1 and the bed layer. The diffusion prevention layer is formed for the purpose of preventing the diffusion of the constituent elements of the substrate 1 and is made of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ), rare earth metal oxide, or the like. The thickness is, for example, 10 to 400 nm. Note that since the crystallinity of the diffusion preventing layer is not questioned, it may be formed by a film forming method such as a normal sputtering method.
Thus, by interposing the diffusion preventing layer between the base material 1 and the bed layer, when other layers such as the intermediate layer 2 and the oxide superconducting layer 3 described later are formed, they are inevitably heated. When a thermal history is received as a result of the heat treatment, it is possible to effectively suppress the diffusion of some of the constituent elements of the base material 1 to the oxide superconducting layer 3 side through the bed layer. As an example of the case where a diffusion preventing layer is interposed between the base material 1 and the bed layer, a combination using Al ₂ O ₃ as the diffusion preventing layer and Y ₂ O ₃ as the bed layer can be exemplified.

  The intermediate layer 2 may have a multilayer structure in which a cap layer is further laminated on the metal oxide layer. The cap layer has a function of controlling the orientation of the superconducting layer 3, diffuses the elements constituting the oxide superconducting layer 3 into the intermediate layer 2, and uses the gas and the intermediate layer 2 used when the oxide superconducting layer 3 is laminated. It has a function etc. which suppress reaction with this. The orientation is controlled by the metal oxide layer.

The cap layer is formed through a process of epitaxially growing on the surface of the metal oxide layer, and then growing the grains in the lateral direction (plane direction) (overgrowth) and selectively growing the crystal grains in the in-plane direction. The ones made are preferred. Such a cap layer has a higher degree of in-plane orientation than the metal oxide layer.
The material of the cap layer is not particularly limited as long as it can exhibit the above functions, but specifically, preferred examples include CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , and Zr ₂ O. ₃ , Ho ₂ O ₃ , Nd ₂ O _{3 and the} like. When the material of the cap layer is CeO ₂ , the cap layer may contain a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.

The thickness of the intermediate layer 2 may be appropriately adjusted according to the purpose, but is usually 0.1 to 5 μm.
When the intermediate layer 2 has a multi-layer structure in which a cap layer is laminated on the metal oxide layer, the thickness of the cap layer is usually 0.1 to 1.5 μm.

The intermediate layer 2 is formed by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, or ion beam assisted vapor deposition (hereinafter abbreviated as IBAD); chemical vapor deposition (CVD). ); Coating pyrolysis method (MOD method); lamination can be performed by a known method for forming an oxide thin film such as thermal spraying. In particular, the metal oxide layer formed by the IBAD method is preferable in that the crystal orientation is high and the effect of controlling the crystal orientation of the oxide superconducting layer 3 and the cap layer is high. The IBAD method is a method of orienting crystal axes by irradiating an ion beam at a predetermined angle with respect to a crystal deposition surface during deposition. Usually, an argon (Ar) ion beam is used as the ion beam. For example, the intermediate layer 2 made of Gd ₂ Zr ₂ O ₇ , MgO or ZrO ₂ —Y ₂ O ₃ (YSZ) can reduce the value of ΔΦ (FWHM: full width at half maximum) which is an index representing the degree of orientation in the IBAD method. Therefore, it is particularly suitable.

The oxide superconducting layer 3 can be widely applied with an oxide superconductor having a generally known composition, such as REBa ₂ Cu ₃ O _y (RE is Y, La, Nd, Sm, Er, Gd, etc. A material made of a material that represents a rare earth element, specifically, Y123 (YBa ₂ Cu ₃ O _y ) or Gd123 (GdBa ₂ Cu ₃ O _y ) can be exemplified. Further, other oxide superconductors, for _{example, Bi 2 Sr 2 Ca n-} 1 Cu n for _{O 4 + 2n + δ} becomes may be used in compositions such as those made of other oxide superconductors having high critical temperatures representative Of course.
The oxide superconducting layer 3 is formed by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, or electron beam vapor deposition; chemical vapor deposition (CVD); coating pyrolysis (MOD). Among them, the laser vapor deposition method is preferable.
The oxide superconducting layer 3 has a thickness of about 0.5 to 5 μm and preferably a uniform thickness.

The stabilizing base layer 4 laminated on the oxide superconducting layer 3 is formed as a layer made of a metal material having good conductivity such as Ag and low contact resistance with the oxide superconducting layer 3.
The reason why the stabilizing base layer 4 is made of Ag is that it has the property of making it difficult for the oxygen doped in the oxide superconducting layer 3 to escape from the oxide superconducting layer 3 in the annealing step of doping the oxide superconducting layer 3 with oxygen. . In order to form the Ag stabilizing base layer 4, a film forming method such as a sputtering method is employed, and the thickness can be formed to about 1 to 30 μm.

The oxide superconducting laminate 5 having the structure shown in FIG. 1B covers and covers the top surface of the oxide superconducting layer 3 with an Ag stabilizing base layer 4. In consideration of the possibility that the superconducting properties may be deteriorated due to intrusion of moisture into the oxide superconducting layer 3, it is necessary to protect with some kind of cover.
In the present embodiment, in order to protect the oxide superconducting layer 3, the first solder layer 6 and a metal tape are wound around the peripheral surface side of the oxide superconducting laminate 5 so as to cover the entire peripheral surface. The oxide superconducting laminate 5 is configured such that the formed first stabilizing layer 7, the second solder layer 8, and the second stabilizing layer 9 formed by winding a metal tape are coated in this order. Adopt a structure that covers the entire circumference.

  The solder constituting the first solder layer 6 and the second solder layer 8 is not particularly limited, and a conventionally known solder can be used. For example, Sn—Ag alloy, Sn—Bi alloy, Sn— Examples include lead-free solders such as Cu-based alloys and Sn-Zn-based alloys, Pb-Sn-based alloy solders, eutectic solders, and low-temperature solders. These solders can be used alone or in combination of two or more. . Among these, it is preferable to use solder having a melting point of 300 ° C. or less. As a result, soldering can be performed at a temperature of 300 ° C. or lower, so that deterioration of the characteristics of the oxide superconducting layer 3 due to heat of soldering can be suppressed. The thickness of the 1st solder layer 6 is not specifically limited, Although it can adjust suitably, For example, it can be set as about 2-20 micrometers. In addition, the kind of solder which comprises the 1st solder layer 6 and the 2nd solder layer 8, and the thickness of the 1st solder layer 6 and the 2nd solder layer 8 may be the same or different, and can be adjusted suitably. .

  The first stabilizing layer 7 and the second stabilizing layer 9 are formed so that the current of the oxide superconducting layer 3 is converted together with the stabilizing base layer 4 when the oxide superconducting layer 3 attempts to transition from the superconducting state to the normal conducting state. It functions as a bypass to flow. The first stabilization layer 7 and the second stabilization layer 9 are formed by winding a long metal tape around the outer periphery of the oxide superconducting laminate 5. The metal tape forming the first stabilization layer 7 and the second stabilization layer 9 is made of a highly conductive metal, and is made of a copper alloy such as Cu, brass (Cu—Zn alloy), Cu—Ni alloy, It is preferable to use a relatively inexpensive material such as stainless steel. Among them, Cu is preferable because it has high conductivity and is inexpensive. The thickness of the 1st stabilization layer 7 and the 2nd stabilization layer 9 is not specifically limited, Although it can adjust suitably, it is preferable to set it as 12.5-300 micrometers. By setting the lower limit value or more, a higher effect of stabilizing the oxide superconducting layer 3 can be obtained, and by setting the upper limit value or less, the oxide superconducting wire 10 can be thinned. Note that the types of metals constituting the first stabilization layer 7 and the second stabilization layer 9 and the thicknesses of the first stabilization layer 7 and the second stabilization layer 9 may be the same or different. It can be adjusted.

The oxide superconducting wire 10 of this embodiment includes a first solder layer 6, a first stabilization layer 7, a second solder layer 8, and a second stabilization layer 9 so as to cover the outer peripheral surface of the oxide superconducting laminate 5. Since the structure is formed, a structure in which all the side surfaces of the oxide superconducting laminate 5 including the oxide superconducting layer 3 are shielded from the outside can be realized. By adopting such a configuration, it is possible to suppress the penetration of moisture into the oxide superconducting layer 3 and prevent the oxide superconducting layer 3 from being damaged by moisture and degrading the superconducting characteristics.
Further, in the conventional oxide superconducting wire 300 shown in FIG. 5, when water droplets W adhere to the wire, a battery is formed by the solder 303 and the metal tape 302 via the water droplets W, and the solder 303 is corroded. There was a case. On the other hand, the oxide superconducting wire 10 of the present embodiment has a configuration in which the entire circumference of the outermost periphery is covered with the second stabilization layer 9 made of a metal tape. The solder layer is not corroded, and moisture permeation into the oxide superconducting layer 3 can be suppressed.

Next, an embodiment of a method for manufacturing the oxide superconducting wire 10 according to the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 2 is a process explanatory diagram for explaining the process of the first embodiment of the method of manufacturing an oxide superconducting wire according to the present invention.
First, the above-described long oxide superconducting laminate 5 and the first stabilizing layer tape 11 having the first solder layer 6a formed on one surface of the metal tape 7a are prepared. The material and thickness of the metal tape 7a are the same as those mentioned as the first metal stabilizing layer 7 of the oxide superconducting wire 10. Also, the solder constituting the first solder layer 6a is the same as that described as the first solder layer 6 of the oxide superconducting wire 10.
Next, as shown in FIG. 2 (a), the oxide superconducting laminate is provided on the outer peripheral surface of the long oxide superconducting laminate 5 with the first stabilizing layer 11 tape and the first solder layer 6a inside. 5 is wound so that the end portions in the width direction of the first stabilizing layer tape 11 of each turn adjacent to each other in the longitudinal direction of 5 are in contact with each other (in the following description, such winding method is abbreviated as “butt wrap winding”). .) Thus, by winding the 1st stabilization layer tape 11 around the oxide superconducting laminated body 5, each 1st stabilization layer tape 11a, 11b, 11c adjacent to the longitudinal direction of the oxide superconducting laminated body 5 is a gap. The end portions of the adjacent first stabilizing layer tapes 11a, 11b, and 11c are in contact with each other.

Subsequently, a second stabilizing layer tape 12 having a second solder layer 8a formed on one surface of the metal tape 9a is prepared. The material and thickness of the metal tape 9a are the same as those mentioned as the second metal stabilizing layer 9 of the oxide superconducting wire 10. Also, the solder constituting the second solder layer 8a is the same as that described as the second solder layer 8 of the oxide superconducting wire 10.
Thereafter, as shown in FIG. 2B, the second stabilization layer is formed on the outer peripheral surface of the composite 20 around which the first stabilization layer tape 11 is wound so as to cover the outer peripheral surface of the oxide superconducting laminate 5. 12 tapes are wound by butt wrap winding with the second solder layer 8a inside. At this time, the first stabilization layer tape 11a, 11b, 11c of each turn adjacent to each other in the longitudinal direction of the oxide superconducting laminate 5 of the composite 20 is covered with the contact portion 21 between the end portions in the width direction. 2 Wrap the stabilizing layer tape 12.
Thus, by winding the second stabilization layer tape 12 around the composite 20, the second stabilization layer tapes 12a, 12b, 12c adjacent to each other in the longitudinal direction of the oxide superconducting laminate 5 are arranged without a gap. The end portions of the adjacent second stabilizing layer tapes 12a, 12b, and 12c are in contact with each other.

  Next, the coated oxide superconducting laminate in which the first stabilizing layer tape 11 and the second stabilizing layer tape 12 are wound so as to cover the outer peripheral surface of the oxide superconducting laminate 5 is subjected to heat treatment and as necessary. By applying the pressure treatment, the first solder layer 6a and the second solder layer 8a are melted, and the metal tapes 7a and 9a are bonded to the outer peripheral surface of the oxide superconducting laminate 5 with sufficient bonding strength. Thus, the first solder layer 6 and the first stabilization layer 7 formed from the first solder layer 6a of the first stabilization layer tape 11 and the metal tape 7a so as to cover the outer peripheral surface of the oxide superconducting laminate 5. Then, the second solder layer 8a of the second stabilization layer tape 12 and the second solder layer 8 and the second stabilization layer 9 formed of the metal tape 9a form an oxide superconducting wire 10 covered in this order. can do.

  FIG.2 (c) is sectional drawing which cut | disconnected the oxide superconducting wire manufactured by the manufacturing method of the oxide superconducting wire of this embodiment along the longitudinal direction. As shown in FIG.2 (c), in the manufacturing method of the oxide superconducting wire of this embodiment, each 1st stabilization layer tape 11a of each turn adjacent to the longitudinal direction of the oxide superconducting laminated body 5 of the composite body 20 is shown. , 11b, 11c so as to cover the contact portion 21 between the end portions in the width direction, the second stabilization layer tape 12 is wound so that the upper surface of the contact portion 21 is the second solder layer 8 and the second stabilization layer 9. Therefore, the hermeticity (air tightness) of the oxide superconducting wire can be improved, and moisture and the like can enter from the outside through the contact portion 21 to further prevent the oxide superconducting layer 3 from being damaged. can do.

  According to the oxide superconducting wire manufacturing method of the present embodiment, it is possible to provide an oxide superconducting wire that can prevent moisture from entering the oxide superconducting layer. Moreover, the manufacturing method of the oxide superconducting wire of this embodiment can manufacture an oxide superconducting wire more simply compared with the method of forming a stabilization layer by the conventional plating method. Furthermore, by adjusting the thickness of the metal tape, a stabilization layer having a desired thickness can be easily formed.

  As mentioned above, although the manufacturing method of the superconducting wire of 1st Embodiment which concerns on this invention was demonstrated, this invention is not limited to this. For example, after winding the first stabilization layer tape 11 so as to cover the outer peripheral surface of the oxide superconducting laminate 5 as shown in FIG. 2 (a), by heating and pressing as necessary, An oxide superconducting wire having a structure in which the outer peripheral surface of the oxide superconducting laminate 5 is covered with the first solder layer 6 and the first stabilizing layer 7 can also be produced. Similarly to the oxide superconducting wire 10 of the first embodiment, the oxide superconducting wire having such a configuration is configured such that all the side surfaces of the oxide superconducting laminate 5 including the oxide superconducting layer 3 are shielded from the outside. Since this can be realized, it is possible to suppress the penetration of moisture into the oxide superconducting layer 3 and prevent the oxide superconducting layer 3 from being damaged by moisture and degrading the superconducting characteristics.

[Second Embodiment]
FIG. 3 is a process explanatory diagram for explaining a process of the second embodiment of the method of manufacturing an oxide superconducting wire according to the present invention.
First, the first solder layer 6b was formed on one surface of the long oxide superconducting laminate 5 and the metal tape 7b, and the second solder layer 8b was formed on the other surface of the metal tape 7b. A first stabilizing layer tape 13 is prepared. The material and thickness of the metal tape 7b are the same as those mentioned as the first metal stabilizing layer 7 of the oxide superconducting wire 10. Also, the solder constituting the first solder layer 6b and the second solder layer 8b is the same as that described as the first solder layer 6 and the second solder layer 8 of the oxide superconducting wire 10.
Next, as shown in FIG. 3 (a), the oxide superconducting laminate is provided on the outer peripheral surface of the long oxide superconducting laminate 5 with the first stabilization layer 13 tape and the first solder layer 6b inside. 5 is wound by butt wrap so that the widthwise ends of the first stabilizing layer tape 13 of each turn adjacent to each other in the longitudinal direction are in contact with each other. By winding the first stabilization layer tape 13 around the oxide superconducting laminate 5 in this way, the first stabilization layer tapes 13a, 13b, 13c adjacent in the longitudinal direction of the oxide superconducting laminate 5 are The end portions of the adjacent first stabilizing layer tapes 13a, 13b, and 13c are in contact with each other.

Subsequently, a second stabilizing layer tape 9b made of a metal tape is prepared. The material and thickness of the metal tape that is the second stabilization layer tape 9 b are the same as those mentioned as the second metal stabilization layer 9 of the oxide superconducting wire 10. Thereafter, as shown in FIG. 3B, the second stabilization layer is formed on the outer peripheral surface of the composite 30 around which the first stabilization layer tape 13 is wound so as to cover the outer peripheral surface of the oxide superconducting laminate 5. 9b tape is wound by butt wrap winding. At this time, the first stabilization layer tape 13a, 13b, 13c of each turn adjacent to each other in the longitudinal direction of the oxide superconducting laminate 5 of the composite 20 is covered with the contact portions 21 between the end portions in the width direction. 2 Wrap the stabilizing layer tape 9b.
By winding the second stabilization layer tape 9b around the composite 30 in this way, the second stabilization layer tapes 13a, 13b, 13c adjacent in the longitudinal direction of the oxide superconducting laminate 5 are arranged without gaps. The end portions of the adjacent second stabilizing layer tapes 13a, 13b, 13c are in contact with each other.

  Next, the coated oxide superconducting laminate in which the first stabilizing layer tape 13 and the second stabilizing layer tape 9b are wound so as to cover the outer peripheral surface of the oxide superconducting laminate 5 is subjected to heat treatment and as necessary. By applying the pressure treatment, the first solder layer 6b and the second solder layer 8b are melted, and the metal tapes 7b and 9b are bonded to the outer peripheral surface of the oxide superconducting laminate 5 with sufficient bonding strength. Accordingly, the first solder layer 6 formed of the first solder layer 6b and the metal tape 7b of the first stabilization layer tape 13 and the second solder layer 8b so as to cover the outer peripheral surface of the oxide superconducting laminate 5 and The oxide superconducting wire 10 in which the first stabilization layer 7 and the second solder layer 8 and the second stabilization layer 9 formed from the second stabilization layer tape 9b are coated in this order can be formed. .

  FIG.3 (c) is sectional drawing which cut | disconnected the oxide superconducting wire manufactured by the manufacturing method of the oxide superconducting wire of this embodiment along the longitudinal direction. As shown in FIG.3 (c), in the manufacturing method of the oxide superconducting wire of this embodiment, each 1st stabilization layer tape 13a of each turn adjacent to the longitudinal direction of the oxide superconducting laminated body 5 of the composite 30 is shown. Since the upper surface of the contact portion 31 is covered with the second stabilization layer 9b by wrapping the second stabilization layer tape 9b so as to cover the contact portion 31 between the end portions in the width direction of 13b, 13b, oxidation The hermeticity (hermeticity) of the superconducting wire can be improved, and it is possible to further prevent moisture from entering from the outside through the contact portion 31 and damaging the oxide superconducting layer 3.

  According to the oxide superconducting wire manufacturing method of the present embodiment, it is possible to provide an oxide superconducting wire that can prevent moisture from entering the oxide superconducting layer. Moreover, the manufacturing method of the oxide superconducting wire of this embodiment can manufacture an oxide superconducting wire more simply compared with the method of forming a stabilization layer by the conventional plating method. Furthermore, by adjusting the thickness of the metal tape, a stabilization layer having a desired thickness can be easily formed.

  In the manufacturing method of the oxide superconducting wire of this embodiment, the first solder layer 6b is formed on one surface of the metal tape 7b, and the second solder layer 8b is formed on the other surface of the metal tape 7b. The first stabilization layer tape 13 and the second stabilization layer tape 9b made of a metal tape are wound around the oxide superconducting laminate 5. Therefore, in this embodiment, if the first solder layer 6b and the second solder layer 8b are configured to be the same solder, the metal tape 7b is filled with the solder constituting the first solder layer 6b and the second solder layer 8b. Since the first stabilization layer tape 13 can be manufactured by immersing it in the solder bath, a simpler manufacturing method can be obtained. The manufacturing method of the first embodiment described above is also simpler than the conventional plating method, but when the solder layer is formed only on one side of the metal tape, it is necessary to mask the other side of the metal tape. The production method of this embodiment is easier to procure the stabilization layer tape.

  The oxide superconducting wire and the manufacturing method thereof according to the present invention have been described above. In the above embodiment, each part of the oxide superconducting wire is an example, and can be appropriately changed without departing from the scope of the present invention. It is. For example, in the above embodiment, the first solder layer 6, the first stabilization layer 7, the second solder layer 8, and the second stabilization layer 9 are formed so as to cover the entire peripheral surface of the oxide superconducting laminate 5. Although the oxide superconducting wire 10 formed in this order is illustrated, the present invention is not limited to this, and the second solder layer 8 and the second stabilization layer 9 can be omitted. Moreover, in the said embodiment, the 1st stabilization layer tape 11 and the 2nd stabilization layer tape 12 in which the solder layer was formed in one surface of a metal tape, or the 1st in which the solder layer was formed in both surfaces of a metal tape Although the example which forms the 1st solder layer 6 and the 2nd solder layer 8 using the stabilization layer tape 13 was shown, this invention is not limited to this. The first solder layer 6 may be formed by immersing the oxide superconducting laminate 5 in a solder bath, or the composite 20 in which the first stabilizing layer tape 11 is wound around the oxide superconducting laminate 5. The second solder layer 8 may be formed by dipping in a solder bath.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.

"Example"
An intermediate layer of Gd ₂ Zr ₂ O ₇ (GZO) having a thickness of 1.2 μm by an IBAD method on a metal substrate made of Hastelloy C276 (trade name, manufactured by Haynes, USA) having a width of 10 mm and a thickness of 0.1 mm. Further, a cap layer having a composition of CeO _{2 having a} thickness of 1.0 μm was formed on the intermediate layer by the PLD method. Next, an oxide superconducting layer having a composition of GdBa ₂ Cu ₃ O _7-x having a thickness of 1.0 μm is formed on the cap layer by a PLD method, and further a thickness of 10 μm is formed on the oxide superconducting layer by a sputtering method. A stabilized base layer of Ag was formed. The obtained laminate was cut along the longitudinal direction to produce an oxide superconducting laminate having a width of 5 mm, a length of 10 m, and a critical current value Ic = 100A.

Next, a first stabilization layer tape having a 5 μm thick tin solder layer formed on one surface of a 20 μm thick Cu tape was prepared. On the outer peripheral surface of the oxide superconducting laminate produced above, FIG. As shown in (a), it was wound with the solder side inside.
Subsequently, a second stabilization layer tape having a 5 μm thick tin solder layer formed on one surface of a 20 μm thick Cu tape was prepared, and the oxide superconducting laminate in which the first solder layer tape was wound was prepared. The second stabilizing layer tape was wound around the outer peripheral surface so that the solder layer was inside and the contact portion of each turn of the first stabilizing layer tape was covered as shown in FIG.
Next, the coated oxide superconducting laminate around which the first stabilizing layer tape and the second stabilizing layer tape are wound so as to cover the outer peripheral surface of the oxide superconducting laminate is heated at a temperature equal to or higher than the melting point of the solder. Thus, a solder layer (first solder layer), a Cu layer (first stabilization layer), a solder layer (second solder layer), and a Cu layer ( An oxide superconducting wire having the structure shown in FIG. 1A was manufactured, in which the second solder layer) was formed in order. The obtained oxide superconducting wire had a critical current value Ic of 100 A, and an oxide superconducting wire could be produced without degrading the superconducting properties of the oxide superconducting laminate.

  The prepared oxide superconducting wire was held in an atmosphere of temperature 123 ° C. and humidity 85% for 300 hours, and then the superconducting property of the oxide superconducting wire was measured. The critical current value Ic was 100 A, and the superconducting property deteriorated. It wasn't.

"Comparative example"
An oxide superconducting laminate having a width of 5 mm, a length of 10 m, and a critical current value Ic = 100 A was produced in the same manner as in the example.
Next, as shown in FIG. 5, the produced oxide superconducting laminate is sandwiched between 100 μm-thick Cu tapes, a tin solder fillet is filled between the Cu tapes, and the oxide superconducting laminate is encapsulated by the solder fillets. An oxide superconducting wire was prepared.
The prepared oxide superconducting wire was held in an atmosphere of a temperature of 123 ° C. and a humidity of 85% for 300 hours, and then the superconducting properties of the oxide superconducting wire were measured. As a result, the critical current value Ic was degraded to almost 0A.

  The present invention can be used for an oxide superconducting wire used in various electric power devices such as a superconducting motor and a current limiting device.

  DESCRIPTION OF SYMBOLS 1 ... Base material, 2 ... Intermediate | middle layer, 3 ... Oxide superconducting layer, 4 ... Stabilization base layer, 5 ... Oxide superconducting laminated body, 6 ... 1st solder layer, 7 ... 1st stabilization layer, 8 ... 2nd Solder layer, 9 ... second stabilization layer, 10 ... oxide superconducting wire, 11, 13 ... first stabilization layer tape, 12, 9b ... second stabilization layer tape.

Claims (7)

  An oxide superconducting laminate comprising a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer; The first solder layer and the first stabilization layer formed by winding the metal tape are covered in this order so as to cover the entire peripheral surface on the peripheral surface side of the oxide superconducting laminate. Characteristic oxide superconducting wire.   A second solder layer and a second stabilization layer formed by winding a metal tape so as to cover the entire outer peripheral surface of the first stabilization layer on the peripheral surface side of the first stabilization layer The oxide superconducting wire according to claim 1, wherein the oxide superconducting wires are coated in this order.   The metal tape so as to cover the contact portion between the widthwise ends of the metal tape of each turn adjacent to the longitudinal direction of the oxide superconducting laminate of the first stabilization layer formed by winding the metal tape. The oxide superconducting wire according to claim 2, wherein the second stabilizing layer is formed by winding a wire. An oxide superconducting laminate comprising a base material, an intermediate layer provided on the base material, an oxide superconducting layer, and an Ag stabilizing base layer provided on the oxide superconducting layer; An oxide in which a first solder layer and a first stabilization layer formed by winding a metal tape are covered in this order so as to cover the entire peripheral surface of the oxide superconducting laminate. A method of manufacturing a superconducting wire,
A first stabilization layer tape having a first solder layer formed on at least one surface of the metal tape is placed on the outer peripheral surface of the oxide superconducting laminate at each turn adjacent to the longitudinal direction of the oxide superconducting laminate. Manufacturing the oxide superconducting wire, wherein the first solder layer and the first stabilization layer are formed by butt wrap winding in which the end portions in the width direction of the first stabilization layer tape are in contact with each other Method.   A first stabilization layer tape having a first solder layer formed on one surface of a metal tape is wound around the outer peripheral surface of the oxide superconducting laminate by the butt wrap, and the first solder layer and the first solder layer are wound. After forming the first stabilizing layer, the first stabilizing layer tape formed on the outer peripheral surface of the oxide superconducting laminate is formed with a second stabilizing layer tape having a second solder layer formed on one surface of the metal tape. 5. The method of manufacturing an oxide superconducting wire according to claim 4, wherein the second solder layer and the second stabilization layer are formed by winding the outer peripheral surface of the layer by the butt wrap winding.   A first stabilization layer tape having a first solder layer formed on one surface of the metal tape and a second solder layer formed on the other surface of the metal tape is disposed on the outer peripheral surface of the oxide superconducting laminate. After winding by the butt wrap winding to form the first solder layer, the first stabilization layer, and the second solder layer, a second stabilization layer tape made of a metal tape is attached to the oxide superconducting laminate. 5. The oxide superconducting wire according to claim 4, wherein the second stabilization layer is formed by winding the second solder layer formed on the outer peripheral surface around the outer peripheral surface by the butt wrap winding. 6. Method.   Wrapping the second stabilization layer tape so as to cover the contact portion between the widthwise ends of the first stabilization layer tape of each turn adjacent to the longitudinal direction of the oxide superconducting laminate. The manufacturing method of the oxide superconducting wire of Claim 5 or 6.

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