JP2013134856A - Oxide superconducting wire material and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconducting wire material which enhances adhesiveness between a protective layer made of Ag or Ag alloy on an oxide superconducting layer and a metal stabilizing layer, and to provide a method for manufacturing the same.SOLUTION: (1) An oxide superconducting wire material 1 comprises: a substrate 2; intermediate layers 3, 4 and 5 provided on an upper side of the substrate 2; an oxide superconducting layer 6; and a protective layer 7 made of Ag or Ag alloy. A metal stabilizing layer 8 is formed on the protective layer 7. The protective layer 7 has a surface roughness Rz ( maximum height) of 1,500 nm or more. (2) The metal stabilizing layer 8 has a thickness of 20 μm-300 μm.

Description

  The present invention relates to an oxide superconducting wire and a method for producing the same.

An RE-123-based oxide superconductor (REBa ₂ Cu ₃ O _7-X : RE is a rare earth element including Y) exhibits superconductivity at a liquid nitrogen temperature and has a low current loss. Therefore, it is an extremely promising material for practical use. It is desired to process this into a wire and use it as a power supply conductor or electromagnetic coil. As an example of the structure of this oxide superconducting wire, a tape-shaped metal substrate with high mechanical strength is used, and an intermediate layer with good crystal orientation is formed on its surface by ion beam assisted film formation (IBAD method). Then, an oxide superconducting layer is formed on the surface of the intermediate layer by a film forming method, a protective layer made of a highly conductive material such as Ag is formed on the surface, and a Cu metal foil or the like is further formed on the surface of the protective layer. An oxide superconducting wire having a stabilizing layer is known.

The significance of forming the protective layer and the stabilization layer is that there is a risk of transition from the superconducting state to the normal conducting state due to disturbance or the like when a current is passed through the oxide superconducting layer. This is for diversion. The stabilizing layer that plays an important role as described above needs to be in close contact with the protective layer and be in a state without peeling. As a method of forming this stabilization layer, a method of forming a stabilization layer having a necessary thickness by Cu plating and a method of bonding a copper foil are performed. In the case of fusing a metal stabilizing layer typified by copper foil, soldering is the mainstream.
For example, Patent Document 1 discloses a method of reducing the separation of an oxide superconducting layer, a protective layer, and a stabilizing layer by wrapping an oxide superconducting wire with a reinforcing material and soldering the reinforcing material to the superconducting wire. ing. A structure in which the entire oxide superconducting wire is covered with a polyimide insulating resin is also known.

JP2011-3494A

  However, in the conventional method disclosed in Patent Document 1, since the end portion of the reinforcing material is bent and both ends of the tape-like superconducting wire are sandwiched, the stabilization layer is merely pressed against the protective layer. . Therefore, it is difficult to apply a pressing force over the entire length of the wire, and the pressing force cannot be made constant by bending the wire. For this reason, it has been required to improve the essential adhesion between the stabilizing layer and the protective layer.

  The present invention has been made in view of the above circumstances, and an oxide superconducting wire having improved adhesion between a protective layer made of Ag or an Ag alloy on the oxide superconducting layer and a metal stabilizing layer, and its production. It aims to provide a method.

  The oxide superconducting wire according to claim 1 of the present invention includes a base material, an intermediate layer provided above the base material, an oxide superconducting layer, and a protective layer of Ag or an Ag alloy, and the protective layer. An oxide superconducting wire having a metal stabilizing layer formed thereon, wherein the protective layer has a surface roughness Rz (maximum height) of 1500 nm or more.

  When the surface roughness Rz of the protective layer of Ag or Ag alloy is 1500 nm or more, the anchoring effect that the metal stabilizing layer adhered to the protective layer easily bites into minute irregularities formed on the surface of the protective layer Thereby, the adhesiveness (adhesiveness) of a protective layer and a metal stabilization layer can be improved.

  The oxide superconducting wire according to claim 2 of the present invention is characterized in that, in claim 1, the metal stabilizing layer has a thickness of 20 μm to 300 μm.

When the thickness of the metal stabilizing layer is in the above range, it becomes easier to prevent peeling of the metal stabilizing layer.
When the thickness of the metal stabilization layer is not more than the upper limit of the above range, the rigidity of the metal stabilization layer is prevented from becoming excessively high, and the metal stabilization layer is prevented from peeling from the protective layer due to stress during use. it can.

  In the method for producing an oxide superconducting wire according to claim 3 of the present invention, an intermediate layer and an oxide superconducting layer are formed above a substrate, and then a pre-protective layer made of Ag or an Ag alloy on the oxide superconducting layer. Is formed by a film forming method, and further oxygen annealing is performed at a temperature at which Ag is recrystallized in an oxygen atmosphere, thereby forming a protective layer of Ag or an Ag alloy having a surface roughness Rz (maximum height) of 1500 nm or more. Then, a metal stabilizing layer is formed on the protective layer.

  By performing oxygen annealing, Ag forming the protective layer is recrystallized, whereby the surface of the protective layer can be roughened so that the surface roughness Rz is 1500 or more. For this reason, the metal stabilizing layer can be more closely adhered to the surface of the protective layer due to the anchor effect, so that the adhesion on the entire bonding interface between the protective layer and the metal stabilizing layer can be improved. In addition, by oxygen annealing, oxygen can be supplied to the oxide superconducting layer to improve the superconducting characteristics.

The method for producing an oxide superconducting wire according to claim 4 of the present invention is characterized in that, in claim 3, the temperature of the oxygen annealing is 300 to 600 ° C.
When the temperature is not less than the lower limit of the above temperature range, oxygen can be sufficiently supplied to the oxide superconducting layer, and it becomes easier to recrystallize Ag contained in the protective layer, and the surface roughness Rz of the protective layer. Can be roughened.
It can prevent that an oxide superconductor layer deteriorates with a heat | fever as it is below the upper limit of the said temperature range.

The method for producing an oxide superconducting wire according to claim 5 of the present invention is characterized in that, in claim 3 or 4, the oxygen annealing is performed for 10 hours or more.
When it is not less than the lower limit of the above time range, the surface roughness Rz of the protective layer can be reliably set to 1500 nm or more.

  In the oxide superconducting wire of the present invention, the metal stabilization layer is in close contact with the protective layer having a surface roughness (maximum height) Rz 1500 nm or more via solder or directly. hard. As a result, the protective layer and the oxide superconducting layer can be physically protected from disturbance, and a current can be flowed stably even when the superconducting state is changed to the normal conducting state by the disturbance.

  According to the method for manufacturing an oxide superconducting wire of the present invention, the surface roughness (maximum height) Rz of the protective layer is set to 1500 nm or more by oxygen annealing at a temperature at which Ag recrystallizes. The effect is improved and the metal stabilizing layer can be strongly adhered to the surface of the protective layer. In addition, oxygen annealing can be sufficiently supplied to the oxide superconducting layer by oxygen annealing in an oxygen atmosphere, so that the superconducting characteristics can be further improved. further,

It is a fragmentary sectional view of a 1st embodiment of an oxide superconducting wire concerning the present invention. It is a schematic diagram which shows the mode of a peeling test.

<Oxide superconducting wire>
Hereinafter, embodiments of the oxide superconducting wire according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.
FIG. 1 is a schematic cross-sectional view schematically showing an oxide superconducting wire 1 according to a first embodiment of the present invention.
In the oxide superconducting wire 1 of this embodiment, an intermediate layer composed of a base layer 3, an alignment layer 4, and a cap layer 5 is formed above a tape-shaped substrate 2, and the oxide superconducting layer 6 and a protective layer are formed thereon. The layer 7 and the metal stabilizing layer 8 are laminated in this order. Furthermore, the insulating coating layer 9 covers the peripheral surface of the oxide superconducting wire 1.

The substrate 2 is preferably in the form of a tape, a sheet, or a thin plate in order to make a long cable, and is preferably made of a heat-resistant metal. Examples thereof include various heat-resistant metal materials such as nickel alloys such as hastelloy, copper alloys, and stainless steel, or ceramics disposed on these various metal materials. Among various refractory metals, nickel alloys are preferred, and Hastelloy (trade name, manufactured by Haynes, USA) is suitable for commercial products. Any kind of Hastelloy B, C, G, N, W, etc., having different amounts of components such as molybdenum, chromium, iron, cobalt and the like can be used. Further, as the base material 2, an oriented Ni—W alloy tape base material in which a texture is introduced into a nickel alloy can be used.
What is necessary is just to adjust the thickness of the base material 2 suitably according to the objective, Usually, it can be set as the range of 10-500 micrometers.

  The underlayer 3 can have a multi-layer structure of a diffusion preventing layer and a bed layer, which will be described below, or a structure composed of one of these layers.

The diffusion preventing layer provided as the underlayer 3 is usually formed for the purpose of preventing the diffusion of the constituent elements or improving the film quality of other layers formed thereon. When a diffusion prevention layer is provided as the underlayer 3, the diffusion prevention layer is formed of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), or GZO (Gd ₂ Zr ₂ O ₇ ). It is preferable that the layer has a single-layer structure or a multi-layer structure composed of the like.

  The thickness in particular of the said diffusion prevention layer is not restrict | limited, For example, it can be 10-400 nm. When the thickness of the diffusion preventing layer is less than 10 nm, there is a possibility that the diffusion of the constituent elements of the substrate 2 cannot be sufficiently prevented only by the diffusion preventing layer. On the other hand, when the thickness of the diffusion preventing layer exceeds 400 nm, the internal stress of the diffusion preventing layer increases, and there is a possibility that the whole including the other layers is easily peeled from the substrate 2. Further, since the crystallinity of the diffusion preventing layer is not particularly limited, it may be formed by a film forming method such as a normal sputtering method.

The bed layer provided as the underlayer 3 is usually formed for the purpose of reducing the interfacial reactivity or obtaining the orientation of the film disposed thereon. When a bed layer is provided as the foundation layer 3, the bed layer is preferably formed of a material having high heat resistance. Examples of such materials include rare earth oxidation such as Y ₂ O ₃ , Er ₂ O ₃ , CeO ₂ , Dy ₂ O _3, Er ₂ O ₃ , Eu ₂ O ₃ , Ho ₂ O ₃ , and La ₂ O _3. Things. The layer structure may be a single layer structure or a multilayer structure.

The thickness of the bed layer is not particularly limited, and can be, for example, 10 to 100 nm. Further, since the crystallinity of the bed layer is not particularly limited, it may be formed by a film forming method such as a normal sputtering method.
The underlayer 3 may be a two-layer structure including a diffusion prevention layer and a bed layer, or may be a single layer structure made of either of these layers. In some cases, the underlayer 3 may be omitted. When the base layer 3 is omitted, an alignment layer 4 described below is formed directly on the substrate 2.

The alignment layer 4 functions as a buffer layer for controlling the crystal orientation of the oxide superconducting layer 6 and is preferably made of a metal oxide having good lattice matching with the oxide superconducting layer 6. The alignment layer 4 is preferably formed by IBAD (ion beam assisted vapor deposition). An alignment layer formed by the IBAD method is excellent in alignment.
Examples of preferable materials for the alignment layer 4 include 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 O. ₃ , metal oxides such as Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ . The alignment layer 4 may be a single layer or a multilayer structure.

The cap layer 5 is preferably formed through a process of epitaxially growing on the surface of the alignment layer 4 and then selectively growing crystal grains in the in-plane direction. Such a cap layer 5 may have a higher in-plane orientation degree than the orientation layer 4.
Preferred materials for the cap layer 5 include, for example, CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , Nd ₂ O _{3 and the} like. When the material of the cap layer 5 is CeO ₂ , the cap layer 5 may include a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion (M). .
The cap layer 5 can be formed by a PLD method (pulse laser deposition method), a sputtering method, or the like. The film thickness of the cap layer 5 made of CeO ₂ is usually 50 nm or more, but is preferably 100 nm or more in order to obtain sufficient orientation. However, since crystal orientation may deteriorate if it is too thick, the thickness is preferably in the range of 50 to 5000 nm.

For the oxide superconducting layer 6, materials widely used for known oxide superconductors can be widely applied. For example, ReBa ₂ Cu ₃ O _7-x (Re is Y, La, Nd, Sm, Er, Gd Represents a rare earth element, etc.). More _{specifically, Y123 (YBa 2 Cu 3 O} 7-x) or _{Gd123 (GdBa 2 Cu 3 O 7} -x) can be exemplified as a preferable. _{Further, Bi 2 Sr 2 Ca n-} 1 Cu n O 4 + 2n + δ is represented by the formula, may be used materials used in high oxide superconductor critical temperature.

  The thickness of the oxide superconducting layer 6 is preferably about 500 to 5000 nm, and preferably has a uniform thickness. The oxide superconducting layer 6 is formed by a physical vapor deposition method (PVD method) such as sputtering, vacuum vapor deposition, laser vapor deposition, or electron beam vapor deposition, chemical vapor deposition (CVD), or pyrolysis of metal organic coating. It can be formed by a method (MOD method) or the like.

  The protective layer 7 is formed so as to cover the upper surface of the oxide superconducting layer 6 and is made of Ag or an Ag alloy. As described later, the protective layer 7 of Ag or Ag alloy of the present embodiment is formed as a pre-protective layer by a physical vapor deposition method such as a sputtering method, and then at a high temperature of about 300 to 600 ° C. in an oxygen atmosphere. Those formed by heat treatment (oxygen annealing treatment) are preferred. The silver particles constituting the protective layer 7 are recrystallized by oxygen annealing, whereby fine irregularities are formed on the surface of the protective layer 7, and the surface roughness Rz (maximum height) is 1500 nm or more. preferable.

  Here, in the present specification and claims, “surface roughness Rz” means “maximum height” described in JIS B 0601: 2001.

In the oxide superconducting wire according to the present invention, the surface roughness Rz of the upper surface of the protective layer 7 is 1500 nm or more, and the unevenness of the surface exerts an anchor effect. Therefore, the adhesion (adhesion) of the metal stabilizing layer 8 to the protective layer 7 Sex) is increased.
When the metal stabilization layer 8 is a metal foil such as Cu, the metal foil is in close contact with the protective layer 7 through solder. In this case, an anchor effect in which the solder bites into the irregularities on the surface of the protective layer 7 is exerted, and the metal stabilizing layer 8 (metal foil 8) and the protective layer 7 pasted over the protective layer 7 through the solder. Adhesion is improved.
When the metal stabilizing layer 8 is a plated layer made of Cu or the like, the anchor effect that the plated layer bites into the irregularities on the surface of the protective layer 7 is exerted, and the metal stabilizing layer 8 made of the plated layer and the protective layer 7 Adhesion is improved.

  As the surface roughness Rz is larger, the solder tends to bite into the surface and the adhesion is further improved. The upper limit of the surface roughness Rz is not particularly limited, and for example, about 2500 nm is a suitable upper limit. The surface roughness Rz of the protective layer 7 is preferably 1500 nm to 2000 nm, and more preferably 1500 nm to 1660 nm.

  The thickness of the protective layer 7 is not particularly limited, but is preferably 1 μm to 30 μm.

  The material of the protective layer 7 is Ag or an Ag alloy. These are preferable because the adhesion to the metal protective layer 8 or the solder is good and the surface can be roughened by oxygen annealing.

The metal stabilization layer 8 is made of a highly conductive metal material foil, a plating layer, or the like. When the oxide superconducting layer 6 is about to transition from the superconducting state to the normal conducting state, the oxide superconducting layer together with the protective layer 7 is used. 6 functions as a bypass to which current of 6 commutates.
The metal material constituting the metal stabilizing layer 8 is not particularly limited as long as it is a highly conductive material that can be formed into a thin foil or a material that can be formed by plating. However, copper (Cu), NiCr (Ni-Cr alloy), Copper alloys such as stainless steel, brass (Cu—Zn alloy) and Cu—Ni alloy are preferable, and among these, a copper alloy having high conductivity and being inexpensive is more preferable. When the oxide superconducting wire 1 is used for a superconducting fault current limiter, the metal stabilizing layer 8 is preferably a high-resistance metal material, for example, a Ni-based alloy such as Ni—Cr.

Although the thickness of the metal stabilization layer 8 is not specifically limited, It is preferable that they are 10 micrometers-500 micrometers, and it is more preferable that they are 20 micrometers-300 micrometers.
When the thickness of the metal stabilizing layer 8 is equal to or more than the lower limit of the above range, the oxide superconducting layer 6 and the protective layer 7 are physically protected from disturbances and the like, and pinholes and tears occur during manufacture and use. Can be prevented.
If the thickness of the metal stabilization layer 8 is not more than the upper limit of the above range, the metal stabilization layer 8 is prevented from becoming too rigid, and the metal stabilization layer 8 is peeled off from the protective layer 7 due to stress during use. Can be suppressed. If the rigidity of the metal stabilizing layer 8 becomes excessively high, the degree of deformation of the metal stabilizing layer 8 and the degree of deformation of the protective layer 7 are largely dissociated when an external force such as bending or twisting is applied. 8 may easily peel from the protective layer 7.

The outer periphery of the oxide superconducting wire 1 according to the first embodiment is covered with an insulating coating layer 9. The insulating coating layer 9 may be formed by winding an insulating tape, or may be coated with an insulating resin. Although the insulating coating layer 9 is not necessarily provided, the oxide superconducting wire according to the present invention is protected from disturbance, and the protective layer 7 and the metal stabilizing layer 8 are physically pressed to be in close contact with each other. Can do.
The material of the insulating tape and the insulating resin is not particularly limited, and a known material such as a polyimide resin can be applied. The thickness of the insulating coating layer 9 is not particularly limited, and may be appropriately adjusted according to the application, and may be set to, for example, 100 μm to 1 mm.

<Oxide superconducting wire manufacturing method>
Below, the manufacturing method of the oxide superconducting wire 1 which concerns on this invention is demonstrated.
First, the intermediate layer and the oxide superconducting layer 6 including the base layer 3, the alignment layer 4, and the cap layer 5 are formed above the base material 2.
As a method of forming the base layer 3 on the base material 2 such as Hastelloy, a known film forming method such as sputtering can be applied as described above.

As a method of forming the alignment layer 4 on the underlayer 3 by the IBAD method, for example, the target is irradiated with an ion beam so that the constituent particles of the target fly on the substrate 2 and are deposited. In contrast, there is a method of irradiating an assist ion beam at a predetermined incident angle. This method can be realized by a known ion beam assisted sputtering apparatus.
When ion irradiation is performed at a predetermined incident angle while depositing target constituent particles on the surface of the underlayer 3, the specific crystal axis of the formed sputtered film is fixed in the ion incident direction, and the c-axis of the crystal Is oriented in the direction perpendicular to the surface of the metal substrate, and the a-axis (or b-axis) of the crystal is oriented in a fixed direction (biaxially oriented) in the plane. For this reason, the alignment layer 4 formed on the underlayer 3 by the IBAD method exhibits a high degree of in-plane alignment.

Subsequently, the cap layer 5 and the oxide superconducting layer 6 are formed. When the oxide superconducting layer 6 is formed on the cap layer 5 having good orientation, the oxide superconducting layer 6 is also crystallized so as to match the orientation of the cap layer 5.
Therefore, the obtained oxide superconducting layer 6 is excellent in quantum connectivity at the crystal grain boundary, and hardly deteriorates in the superconducting characteristics at the crystal grain boundary. High critical current is obtained, and excellent superconductivity is exhibited.

Next, a pre-protection layer made of Ag or an Ag alloy is formed by a film forming method so as to cover the upper surface of the oxide superconducting layer 6.
The pre-protection layer can be formed by sputtering using Ag or an Ag alloy as a target.

  Subsequently, the oxide superconducting layer 6 provided with the pre-protection layer is heated (oxygen annealing) in an oxygen atmosphere. By performing oxygen annealing, oxygen is supplied to the oxide superconducting layer 6 to improve its superconducting characteristics.

  In addition, in oxygen annealing, the surface roughness Rz of the upper surface of the protective layer 7 can be set to 1500 nm or more by heating at a temperature at which Ag particles recrystallize. As a mechanism for roughening the surface of the upper surface, recrystallization of Ag or coarsening of the Ag crystal may be cited as one factor, and other factors include stress accumulated in the pre-protection layer during sputtering during oxygen annealing. It may be released by heating.

The temperature of the oxygen annealing is preferably 300 to 600 ° C.
When it is at least the lower limit value of the above temperature range, Ag contained in the protective layer 7 can be recrystallized more reliably, and the surface roughness Rz of the protective layer 7 can be reliably roughened.
It can prevent that the oxide superconducting layer 6 and an intermediate | middle layer deteriorate with heat as it is below the upper limit of the said temperature range.

The oxygen annealing is preferably performed for 10 hours or more.
It becomes easier for the surface roughness Rz of the protective layer 7 to be 1500 nm or more when it is at least the lower limit of the above time range. If it is less than 10 hours, a region having a rough surface and a region not yet rough may be mixed. In this case, the adhesion between the protective layer 7 and the metal stabilizing layer 8 may not be sufficient.

  Next, the metal stabilization layer 8 can be formed on the protection layer 7 by a method such as laminating the metal stabilization layer 8 with a solder layer on the protection layer 7 and performing roll pressure bonding. Or you may form the metal stabilization layer 8 which consists of a plating layer on the protective layer 7 with a well-known plating method.

First, an Al ₂ O ₃ diffusion-preventing layer (thickness: 80 nm), which is a base layer, is formed on a tape-shaped base body having a width of 10 mm, a thickness of 100 μm, and a length of 1000 mm made of Hastelloy C-276 (trade name of Haynes, USA). And a Y ₂ O ₃ bed layer (thickness 30 nm) as an underlayer, an MgO orientation layer (thickness 10 nm) formed by the IBAD method, and a CeO ₂ cap layer (thickness 300 nm) formed by the PLD method. An intermediate layer and an oxide superconducting layer (thickness 1 μm) having a composition represented by YBa ₂ Cu ₃ O _7-x formed by the PLD method were laminated in this order.

Next, a pre-protection layer (thickness 10 μm) of AgO was formed by a sputtering method using an Ag plate as a target so as to cover the upper surface of the oxide superconducting layer.
It was 820 nm when the surface roughness (maximum height) Rz of the upper surface of the formed pre protective layer was measured.

  Subsequently, the tape-shaped substrate on which the pre-protection layer was formed was accommodated in a heating furnace having an oxygen-containing atmosphere, and oxygen annealing treatment was performed using a plurality of samples at 500 ° C. for the time shown in Table 1. It was. The results of measuring the surface roughness (maximum height) Rz of the upper surface of the protective layer made of Ag of each sample obtained thereafter are also shown in Table 1.

The surface roughness Rz (maximum height) was measured by the following method.
For the pre-protection layer before the oxygen annealing treatment or the protection layer after the oxygen annealing treatment, 10 Rz values were measured using a contact-type surface roughness measuring device, and the average value was calculated.

  In addition, about the oxide superconducting wire which concerns on this invention, the method using the said contact-type surface roughness measuring device is applicable as a method of investigating the surface roughness Rz of the protective layer distribute | arranged to the inside.

Next, for each sample, a Cu foil or NiCr foil tape with a solder layer was bonded to obtain an oxide superconducting wire having Cu or NiCr as a metal stabilizing layer.
Next, as shown in FIG. 2, each obtained oxide superconducting wire 21 is bent in a U shape, one end is fixed to a pedestal 22, and a spring balance 23 is connected to the other end to form a U-shaped superconductivity. The central portion of the wire 21 was wound around a cylindrical roll 24. The diameter of the roll 24 (roll diameter) was as shown in Table 2. The spring scale 23 was pulled in a direction away from the roll 24 (in the direction of the arrow in the figure), and a peeling test was performed by applying a force so as to apply tension to the wire using the circumferential surface of the roll 24. The tension applied by the spring balance was 5 kgf.

  In this peeling test, it was examined whether peeling occurred. The evaluation results are also shown in Table 2 with “X” when the metal foil peels off and “◯” when the metal foil does not peel off.

From the above results, it is clear that the adhesiveness of the metal foil is improved when the surface roughness Rz of the upper surface of the protective layer is 1500 nm or more.
Further, as the thickness of the metal stabilizing layer (metal foil) increases, peeling tends to occur. (1) The thicker the metal stabilizing layer, the larger the tensile moment applied when it is bent. This is probably because Hastelloy, which is a material, is hard, and the tensile stress is maintained by Hastelloy, but when the metal stabilization layer becomes thick, the stress is also applied to the metal stabilization layer.
Moreover, it is considered that the NiCr foil is more easily peeled than the Cu foil because the NiCr foil is more rigid than the Cu foil.

  The present invention provides an oxide superconducting wire that can be used for, for example, an oxide superconducting power transmission line or a coil winding for a superconducting magnet.

DESCRIPTION OF SYMBOLS 1 ... Oxide superconducting wire, 2 ... Base material, 3 ... Underlayer, 4 ... Orientation layer, 5 ... Cap layer, 6 ... Oxide superconducting layer, 7 ... Protective layer, 8 ... Metal stabilization layer (metal foil), 9: Insulating coating layer.

Claims (5)

An oxide superconducting wire comprising a base material, an intermediate layer provided above the base material, an oxide superconducting layer, and a protective layer of Ag or an Ag alloy, wherein a metal stabilizing layer is formed on the protective layer; There,
An oxide superconducting wire, wherein the protective layer has a surface roughness Rz (maximum height) of 1500 nm or more.   The oxide superconducting wire according to claim 1, wherein the metal stabilizing layer has a thickness of 20 μm to 300 μm.   After forming the intermediate layer and the oxide superconducting layer above the substrate, a pre-protection layer made of Ag or an Ag alloy is formed on the oxide superconducting layer by a film forming method, and Ag is recrystallized in an oxygen atmosphere. By performing oxygen annealing at a temperature, a protective layer of Ag or an Ag alloy having a surface roughness Rz (maximum height) of 1500 nm or more is formed, and then a metal stabilizing layer is formed on the protective layer. A method for producing an oxide superconducting wire.   The temperature of the said oxygen annealing is 300-600 degreeC, The manufacturing method of the oxide superconducting wire of Claim 3 characterized by the above-mentioned.   The method for producing an oxide superconducting wire according to claim 3 or 4, wherein the oxygen annealing is performed for 10 hours or more.

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