JP6069269B2 - Oxide superconducting wire, superconducting equipment, and oxide superconducting wire manufacturing method - Google Patents

Description

  The present invention relates to an oxide superconducting wire, a superconducting device, and a method for manufacturing an oxide superconducting wire.

The RE123-based oxide superconductor is represented by a composition of RE ₁ Ba ₂ Cu ₃ O _7-x (RE: rare earth elements such as Y and Gd), and has a critical temperature higher than the liquid nitrogen temperature (77 K). Researches have been conducted in various places to apply these oxide superconducting conductors to various superconducting devices such as superconducting magnets, transformers, current limiters, and motors.

  In order to use an oxide superconductor for various superconducting devices, the oxide superconductor is generally processed into a wire and used as an oxide superconducting wire such as a power supply conductor or a magnetic coil. Specifically, an oxide superconducting wire in which an oxide superconducting tape having an Ag layer provided on the surface of an oxide superconductor layer and a stabilizing material tape (stabilizing layer) are joined via solder is known. Yes. By providing the Ag layer on the surface of the oxide superconducting layer, it is possible to protect the oxide superconducting layer and to prevent the oxide superconducting layer from being deteriorated by moisture.

However, when solder is joined to the Ag layer, an alloy layer is formed at the interface between the Ag layer and the solder, resulting in a decrease in electrical stability. Further, when Ag is alloyed, it becomes brittle and the strength deteriorates, so that there is a problem that the stabilizing layer peels off from the Ag layer.
Therefore, in Patent Document 1, a plated layer made of an alloy such as Cu is provided on the Ag layer, and the embrittlement of Ag is suppressed by restricting the contact between the Ag layer and the solder.

JP 2013-218915 A

  In the technique described in Patent Document 1, since the plating layer provided between the Ag layer and the solder layer is formed by plating, it is very thick and costs about 20 μm. In some cases, pinholes may occur in the Ag layer. When plating is performed in such a case, the plating solution may come into contact with the oxide superconducting layer below the Ag layer, and the superconducting characteristics may be deteriorated.

  This invention is made | formed in view of the said subject, Comprising: It aims at providing the oxide superconducting wire excellent in cost and a superconducting characteristic, suppressing peeling of the stabilization layer by embrittlement of Ag.

In order to solve the above problems, an oxide superconducting wire according to the present invention includes a laminate in which a tape-shaped base material, an intermediate layer, and an oxide superconducting layer are laminated, and a main surface of the oxide superconducting layer of the laminate. A first protective layer stacked on the first protective layer, a second protective layer stacked on the main surface of the first protective layer, a stabilization layer bonded to the main surface of the second protective layer via a solder layer, The first protective layer is made of Ag or an Ag alloy, the thickness formed by one film forming step of the second protective layer is 2.1 μm or less, and the final thickness is 0.3 μm or more. 10 μm or less.
According to this configuration, the second protective layer is formed between the first protective layer made of Ag or an Ag alloy and the solder layer. Thereby, Ag or an Ag alloy does not contact with the solder, and it can be suppressed that the solder is alloyed with Ag and embrittled. Therefore, it is possible to prevent the stabilization layer from peeling from the oxide superconducting wire.
In addition, by setting the second protective layer made of Cu or Cu alloy to 0.3 μm or more and 10 μm or less, the thickness of the second protective layer in the cross section of the oxide superconducting wire is reduced, thereby reducing cost. , Peeling of the stabilization layer due to embrittlement of Cu can be prevented.
Not only Ag but also Cu is embrittled by alloying with solder. As a result of intensive studies by the present inventors, it has been found that embrittlement occurs when Cu and solder are alloyed when Cu is less than 0.3 μm. Accordingly, by setting the second protective layer made of Cu or Cu alloy to 0.3 μm or more, it is possible to prevent the stabilization layer from peeling off due to Cu alloying.
The second protective layer having such a thickness can be obtained by forming a film of Cu or Cu alloy by sputtering. If an attempt is made to deposit Cu or a Cu alloy exceeding 2.1 μm in a single deposition process in the sputtering method, oxygen in the oxide superconducting layer may escape and the crystal structure may be damaged, leading to deterioration of superconducting characteristics. . By setting the thickness formed by one film formation process of the second protective layer to 2.1 μm or less, the characteristics of the oxide superconducting wire are not deteriorated.

In the above oxide superconducting wire, the oxide superconducting layer may be formed to include a neutral surface in the thickness direction of the entire wire.
According to this configuration, the neutral surface of the oxide superconducting wire is arranged on the oxide superconducting layer, and the load applied to the oxide superconducting layer with respect to bending can be minimized.

In the above oxide superconducting wire, it has a back layer made of Cu or Cu alloy laminated on the back surface of the laminate on the substrate side, and the stabilizing layer has side surfaces on both sides from the main surface of the laminate. It may be arranged so as to reach the back surface and be joined to the back surface layer via a solder layer.
According to this configuration, the stabilization layer can be bonded to the back surface side via the solder layer by forming the back surface layer made of Cu or Cu alloy having excellent adhesion to the solder on the back surface of the laminate. Therefore, the oxide superconducting wire can improve the airtightness of the oxide superconducting wire by bringing the stabilization layer into close contact with the outer periphery of the cross section of the laminate.

In the above oxide superconducting wire, the stabilization layer may be made of any one of a group consisting of Ni—Cr alloy, Ni alloy, stainless steel, and brass.
According to this structure, the electrical resistance at room temperature of the oxide superconducting wire can be increased by using a metal having a relatively high electrical resistance value as the stabilization layer. Therefore, the effect of suppressing instantaneously the overcurrent generated when quenching occurs and transitions to the normal conducting state is high, and an oxide superconducting wire suitable for a superconducting current limiter can be supplied.

A superconducting device of one embodiment has the oxide superconducting wire described above.
According to this configuration, it is possible to provide a superconducting device having high reliability.

The manufacturing method according to an embodiment of the oxide superconducting wire described above provides a laminate in which an intermediate layer and an oxide superconducting layer are formed on a tape-shaped base material, and the main surface of the oxide superconducting layer of the laminate In addition, a first protective layer forming step of forming a first protective layer made of Ag or an Ag alloy by a sputtering method, and a main surface of the first protective layer made of Cu or a Cu alloy by a sputtering method has a thickness of 0. A second protective layer forming step for forming a second protective layer of 3 μm or more and 2.1 μm or less, and a stabilization layer by bonding a metal tape to the main surface of the second protective layer via a solder layer The second protective layer film forming step includes one or more film forming steps, and a film formation of 2.1 μm or less is performed in one film forming step.
According to this configuration, it is possible to form an oxide superconducting wire in which Ag or an Ag alloy is not brought into contact with solder. This can provide an oxide superconducting wire in which the stabilization layer is difficult to peel off.
Further, a thin second protective layer of 2.1 μm or less can be formed by forming a film of Cu or Cu alloy by sputtering. By setting the film thickness of the second protective layer to 2.1 μm or less, the characteristics of the oxide superconducting wire are not deteriorated only by performing a single film formation step.

In the above-described oxide superconducting wire manufacturing method, before the step of forming the stabilization layer, a back layer made of Cu or a Cu alloy is formed by sputtering on the back surface of the laminate on the substrate side. In the step of forming the stabilization layer, the metal tape is disposed so as to wrap around from the main surface of the laminate to the back surface through the side surfaces on both sides, and through the solder layer. You may join to the said back surface layer.
According to this configuration, the back surface layer made of Cu or Cu alloy having excellent adhesion to the solder is formed on the back surface of the laminated body, and the stabilization layer is closely adhered to the outer periphery of the cross section of the laminated body, thereby improving the airtightness. Oxide superconducting wire can be manufactured. Thereby, it can prevent that a water | moisture content permeates into an oxide superconducting layer, and can suppress that a superconducting characteristic deteriorates.

In the oxide superconducting wire of the present invention, a second protective layer is formed between the first protective layer made of Ag or an Ag alloy and the solder layer. Therefore, Ag or an Ag alloy does not come into contact with the solder and can suppress the alloying of the solder with Ag and embrittlement. Therefore, it is possible to prevent the stabilization layer from peeling from the oxide superconducting wire.
In addition, by setting the second protective layer made of Cu or Cu alloy to be 0.3 μm or more and 2.1 μm or less, the thickness of the second protective layer in the cross section of the oxide superconducting wire is reduced and the cost is reduced. , Peeling of the stabilization layer due to embrittlement of Cu can be prevented.

1 is a cross-sectional perspective view schematically showing an oxide superconducting wire according to a first embodiment of the present invention. It is a section inclination figure showing typically the oxide superconducting wire of a 2nd embodiment concerning the present invention. An example of a superconducting coil is shown. FIG. 3A is a perspective view showing a laminated body of superconducting coils, and FIG. 3B is a perspective view showing a single superconducting coil. It is sectional drawing which shows an example of a superconducting fault current limiter.

  Hereinafter, embodiments of an oxide superconducting wire according to the present invention will be described with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent. The present invention is not limited to the following embodiment.

<First Embodiment>
FIG. 1 is a schematic cross-sectional view of the oxide superconducting wire 1 according to the first embodiment. The oxide superconducting wire 1 of this embodiment includes a laminated body 16 in which an intermediate layer 11 and an oxide superconducting layer 12 are laminated on a tape-like base material 10, and a main surface 12a of the oxide superconducting layer 12 of the laminated body 16. The first protective layer 13 laminated on the first protective layer 13, the second protective layer 14 laminated on the main surface 13 a of the first protective layer 13, and the main surface 14 a of the second protective layer 14 joined via the solder layer 19. And a stabilizing layer 18 to be configured.
In FIG. 1, the width direction of the wire is the X direction, the longitudinal direction is the Y direction, and the thickness direction is the Z direction.

As the base material 10, a nickel alloy represented by Hastelloy (trade name, manufactured by Haynes, USA), an oriented Ni—W alloy in which a texture is introduced into a nickel alloy is applied.
The thickness _{T 10} of the substrate 10 may be appropriately adjusted according to the purpose, it may be in the range of 10 to 500 [mu] m.

The intermediate layer 11 is formed on the base material 10. As an example, the intermediate layer 11 may have a laminated structure of a diffusion prevention layer, a bed layer, an alignment layer, and a cap layer in order from the base material side, but one or both of the diffusion prevention layer and the bed layer are omitted. May be.
The thickness _{T 10} of the intermediate layer 11 is about 0.01 m to 5 m.
The diffusion prevention layer is made of Si ₃ N ₄ , Al ₂ O ₃ , GZO (Gd ₂ Zr ₂ O ₇ ), etc., and is formed to a thickness of 10 to 400 nm, for example.
The bed layer is a layer for reducing the interfacial reactivity and obtaining the orientation of the film formed thereon. 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 , La ₂ O _3, etc., and the thickness is, for example, 10 to 100 nm.
The orientation layer is formed from a biaxially oriented material in order to control the crystal orientation of the cap layer thereon. As the material of the alignment layer, 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 , Zr ₂ Examples thereof include metal oxides such as O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ . This alignment layer is preferably formed by an IBAD (Ion-Beam-Assisted Deposition) method.
The cap layer is formed on the surface of the above-described alignment layer and is made of a material that allows crystal grains to self-orient in the in-plane direction. Specifically, CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd _{2 O 3, ZrO 2, YSZ,} Ho 2 O 3, Nd 2 O 3, consist of LaMnO ₃ like. The film thickness of the cap layer can be formed in the range of 50 to 5000 nm.

The oxide superconducting layer 12 may be a known oxide superconductor, and specifically, REBa ₂ Cu ₃ O _7-X (RE is a rare earth element, Sc, Y, La, Ce). , Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are represented. Examples of the oxide superconducting layer 12 include Y123 (YBa ₂ Cu ₃ O _7-X ) or Gd123 (GdBa ₂ Cu ₃ O _7-X ).
The thickness _{T 12} of the oxide superconducting layer 12 is preferably be about 0.5 to 5 [mu] m, a uniform thickness.

  The laminate 16 is configured by the base material 10, the intermediate layer 11, and the oxide superconducting layer 12 described above.

  The first protective layer 13 is a layer made of Ag or an Ag alloy formed on the main surface 12 a of the oxide superconducting layer 12. The first protective layer 13 may be formed not only on the main surface 12 a but also on the side surface 16 b and the back surface 16 c of the stacked body 16.

  The first protective layer 13 serves to protect the oxide superconducting layer 12. It also bypasses overcurrent that occurs in the event of an accident. In addition, the chemical reaction occurring between the oxide superconducting layer 12 and a layer provided on the upper surface of this layer is suppressed, and a part of the elements of one layer penetrates into the other layer and the composition is broken. It has functions such as preventing deterioration of superconducting properties. The first protective layer 13 can be formed by a film formation method such as sputtering at room temperature.

The thickness _{T 13} in the oxide superconducting layer 12 on the first protective layer 13 may be a 1μm or 2μm or less. It is possible to reduce the cost by suppressing the amount of Ag to use the thickness T ₁₃ in the first protective layer 13 by a 2μm or less. Further, by setting the thickness T ₁₃ or more 1 [mu] m, even Ag is agglomerated by heat treatment during oxygen annealing can be suppressed pinholes first protective layer 13 is generated. If a pinhole is generated in the first protective layer 13, the oxide superconducting layer 12 is exposed, and the exposed portion is not protected by the first protective layer 13, and the superconducting characteristics may be deteriorated. The T ₁₃ With more than 1 [mu] m, it is possible to reliably protect the oxide superconducting layer 12.

The second protective layer 14 is a layer made of Cu or a Cu alloy formed on the main surface 13 a of the first protective layer 13. The second protective layer 14 may be formed not only on the main surface 13 a but also on the side surface 16 b and the back surface 16 c of the stacked body 16.
The second protective layer 14 protects the oxide superconducting layer 12 together with the first protective layer 13 and bypasses an overcurrent generated at the time of an accident. Further, the metal (for example, Sn) constituting the solder layer 19 is prevented from diffusing into the first protective layer 13. Thereby, Ag which is a constituent element of the first protective layer 13 and a metal (for example, Sn) constituting the solder layer are prevented from being alloyed.
Even if a pinhole is formed in the first protective layer 13, the formation of the second protective layer 14 can cover the pinhole and reliably protect the oxide superconducting layer 12. it can.

The second protective layer 14, the thickness _{T 14} of the portion formed on the main surface 13a of the first protective layer 13 is preferably 0.3μm or more 10μm or less. The thickness _{T 14} is, 0.3 [mu] m or more, and more preferably less 2.1 .mu.m.
By setting the thickness T ₁₄ and 10μm or less, the oxide superconducting wire 1 can suppress the amount of the material (Cu or Cu alloy) constituting the second protective layer 14 at the cross section, it is possible to reduce the cost it can.

The second protective layer 14 is obtained by forming a film of Cu or Cu alloy by a sputtering method described later. If the second protective layer 14 having a thickness exceeding 2.1 μm is formed in a single film formation step by sputtering, the oxide superconducting layer 12 may be deteriorated. Therefore, the thickness of the second protective layer 14 formed at a time is more preferably 2.1 μm or less. In order to suppress the deposition cost by suppressing the deposition number, the final thickness T ₁₄ of the second protective layer 14 is also preferably less 2.1 .mu.m.
Further, the film formation performed a plurality of times, when the thickness T ₁₄ of the second protective layer 14 to a thickness of more than 2.1μm is stabilized layer due to a solder alloyed with Cu of the second protective layer 14 18 can be more reliably prevented.

  Moreover, peeling of the stabilization layer 18 by alloying of Cu can be prevented by making the 2nd protective layer 14 into 0.3 micrometer or more. When the solder layer 19 is formed on the second protective layer 14 made of Cu or Cu alloy, the metal (for example, Sn) constituting the solder layer 19 diffuses into the second protective layer 14. Thereby, Cu which is a constituent element of the second protective layer 14 and a metal (for example, Sn) constituting the solder layer are alloyed to cause embrittlement of the second protective layer 14. When the embrittlement reaches the entire thickness of the second protective layer 14, the stabilization layer 18 easily peels from the boundary between the first protective layer 13 and the second protective layer 14. Since the diffusion of the metal constituting the solder into Cu or Cu alloy is less than 0.3 μm, the stabilization of the stabilization layer 18 due to Cu alloying can be achieved by setting the second protective layer 14 to 0.3 μm or more. Can be prevented.

The second protective layer 14 can be formed by a film forming method such as a sputtering method at room temperature. An example of forming the second protective layer 14 by sputtering will be described below.
First, the laminated body 16 in which the target which consists of Cu or Cu alloy, and the 1st protective layer 13 was formed is arrange | positioned in the processing container which pressure-reduced the inside to the vacuum state and introduce | transduced Ar gas. At this time, the first protective layer 13 is arranged in the target direction. Next, plasma is generated by ionizing Ar gas by applying a voltage to the target to cause discharge. Ar ions generated in the plasma sputter the target to sputter Cu (or Cu alloy) sputtered particles from the target, and the sputtered particles are deposited on the first protective layer 13 for second protection. Layer 14 is deposited.

In film formation by sputtering, when sputtered particles (Cu particles) collide with the film formation target (first protective layer 13), the kinetic energy at the time of collision is converted into thermal energy, and the temperature of the film formation increases. When this heat is transmitted to the oxide superconducting layer 12 and the temperature of the oxide superconducting layer 12 rises, oxygen in the oxide superconducting layer 12 may escape and the crystal structure may be damaged, leading to deterioration of superconducting characteristics.
The temperature rise of the deposition target has a correlation with the film thickness (film formation rate) of the second protective layer 14 formed at a time. In order to suppress deterioration of the superconducting characteristics of the oxide superconducting layer 12, it is preferable that the film thickness of the second protective layer 14 formed at one time be 2.1 μm or less.
Further, Ag in the first protective layer 13 may be recrystallized due to the temperature rise of the deposition target in the formation of the second protective layer 14 by sputtering. Ag aggregates by recrystallization and forms a pinhole. When the film thickness of the second protective layer 14 is set to 2.1 μm or less at a time, the temperature rise can be suppressed and Ag recrystallization can be prevented.

The solder layer 19 is disposed between the second protective layer 14 and the stabilization layer 18 made of a metal tape, and joins them.
The solder layer 19 can be formed as Sn plating formed on one surface of the metal tape. By placing a metal tape on which Sn plating has been applied on the second protective layer 14 and applying heat, the Sn plating can be melted and solidified to join the metal tape and the second protective layer 14.
The thickness T ₁₉ of the solder layer 19 is about 2 μm.

  The solder used for the solder layer 19 is not particularly limited, and a conventionally known solder can be used. For example, lead-free solder, Pb-Sn alloy alloy, Sn, Sn—Ag alloy, Sn—Bi alloy, Sn—Cu alloy, Sn—Zn alloy, etc. Crystal solder, low-temperature solder, and the like can be mentioned, and these solders can be used singly or in combination of two or more. Among these, it is preferable to use solder having a melting point of 300 ° C. or less. Thereby, since it becomes possible to solder a metal tape and the 2nd protective layer 14 at the temperature of 300 degrees C or less, it can suppress that the characteristic of the oxide superconducting layer 12 deteriorates with the heat of soldering.

The stabilization layer 18 is made of a metal tape bonded onto the second protective layer 14 via the solder layer 19.
The material of the metal tape constituting the stabilization layer 18 is not particularly limited as long as it has good conductivity. For example, it is preferable to use a copper alloy such as copper, brass (brass, Cu—Zn alloy), Cu—Ni alloy, etc., a relatively inexpensive material such as Ni alloy, stainless steel, etc. However, copper is preferable because it is relatively inexpensive.
In the oxide superconducting wire 1, the stabilization layer 18 serves as a bypass for commutating overcurrent generated at the time of an accident.
In addition, when the oxide superconducting wire 1 is used for a superconducting fault current limiter, the stabilization layer 18 is used to instantaneously suppress an overcurrent that occurs when a quench occurs and transitions to a normal conducting state. In this case, the stabilization layer 18 is preferably made of a high-resistance metal made of any one of the group consisting of Ni—Cr alloy, Ni alloy, stainless steel, and brass. In particular, as the Ni alloy, Inconel (registered trademark) or Hastelloy (registered trademark) can be used.
The thickness _{T 18} of the stabilizing layer 18 can be appropriately adjusted, it is possible, for example, 10μm or 150μm or less. If the thickness of the metal tape is too thin, it may be broken during the processing step. Also, if too thick a thickness T ₁₈ of the stabilizing layer 18, on the bending of the wire is damaged, the oxide superconducting wire 1, the occupancy of the stabilizing layer 18 is increased in cross section, the entire wire The critical current density Jc (overall Jc) becomes small.

In the present embodiment, the example in which the stabilization layer 18 is formed by joining the metal tape only on the second protective layer 14 via the solder layer 19 has been described. However, the configuration of the stabilization layer 18 is not limited thereto. It is not a thing.
For example, a metal tape may be molded into a substantially C-shaped cross section and joined via solder so as to cover the back surface 16c side of the laminate 16. Further, a metal tape may be spirally wound around the outer periphery of the wire through solder. As described above, by forming a stabilization layer that covers the peripheral surface of the wire, an airtight structure that does not allow moisture to enter the oxide superconducting layer can be realized, and deterioration of superconducting characteristics can be suppressed.

In the oxide superconducting wire 1 of the present embodiment configured as described above, the oxide superconducting layer 12 is preferably formed so as to include a neutral surface in the thickness direction of the entire wire.
When it is assumed that the rigidity of each layer is substantially the same, the oxide superconducting layer 12 is preferably formed so as to include a position that is half the thickness of the entire wire. More specifically, the thickness of each layer is preferably configured to satisfy the following relationship.
The thickness _{T 13} of the first protective layer 13, and the sum of the thickness _{T 18} of the second thickness _{T 14} of the protective layer 14, the thickness _{T 19} of the solder layer 19, and stabilizing layer 18, the thickness _{T 10} of the base 10 and, The difference from the sum of the thickness T ₁₁ of the intermediate layer 11 is less than half of the thickness T ₁₂ of the oxide superconducting layer 12.
That is, it is preferable to satisfy the following formula.

  When satisfying this relationship, the oxide superconducting layer 12 is disposed in the center of the thickness of the oxide superconducting wire 1, and the neutral surface when the oxide superconducting wire 1 is bent in the thickness direction is the oxide superconducting layer. Configured inside. Therefore, when the oxide superconducting wire 1 is bent, the bending stress applied to the oxide superconducting layer among the bending stress applied to each layer is minimized. Therefore, the load applied to the oxide superconducting layer 12 can be reduced, and deterioration of the superconducting characteristics can be suppressed.

Second Embodiment
The schematic diagram of the cross section of the oxide superconducting wire 2 of 2nd Embodiment is shown in FIG. The oxide superconducting wire 2 according to the second embodiment differs from the oxide superconducting wire 1 according to the first embodiment in that the oxide superconducting wire 2 has a configuration in which the outer periphery of the laminate 16 is covered with the stabilization layer 28. .
In addition, about the component of the same aspect as the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. Also in FIG. 2, as in FIG. 1, the width direction of the wire is the X direction, the longitudinal direction is the Y direction, and the thickness direction is the Z direction.

  The oxide superconducting wire 2 has a laminate 16 in which an intermediate layer 11 and an oxide superconducting layer 12 are laminated on a tape-like substrate 10. A first protective layer 13 is laminated on the main surface 12 a of the oxide superconducting layer 12 of the multilayer body 16. Further, a second protective layer 24 is formed on the main surface 13 a of the first protective layer 13. Further, the back surface layer 26 is laminated on the back surface 16 c on the substrate 10 side of the laminate 16, and the side layer 25 is laminated on the side surface 16 b of the laminate 16. Therefore, the outer periphery (transverse outer periphery) of the multilayer body 16 is covered with the second protective layer 24, the side surface layer 25, and the back surface layer 26. Further, a stabilization layer 28 is bonded to the second protective layer 24, the side layer 25, and the back layer 26 via a solder layer 29.

The second protective layer 24 is a layer made of Cu or Cu alloy formed on the main surface 13 a of the first protective layer 13. The second protective layer 24 is formed integrally with the side surface layer 25 and the back surface layer 26.
The second protective layer 24 protects the oxide superconducting layer 12 together with the first protective layer 13 and bypasses an overcurrent generated at the time of an accident. Further, the metal (for example, Sn) constituting the solder layer 29 is prevented from diffusing into the first protective layer 13 and being alloyed.
Even if a pinhole is formed in the first protective layer 13, the second protective layer 24 is formed to cover the pinhole and prevent the solder from reaching the oxide superconducting layer 12. be able to.

The thickness of the second protective layer 24 is preferably 0.3 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 2.1 μm or less.
By setting the thickness of the second protective layer 24 to 10 μm or less, the amount of material (Cu or Cu alloy) constituting the second protective layer 24 can be suppressed, and cost reduction can be achieved.
The second protective layer 24 can be formed by a film forming method such as a sputtering method at room temperature. By setting the thickness of the second protective layer 24 formed at a time to 2.1 μm or less, heat generated during film formation can be reduced and oxygen in the oxide superconducting layer 12 can be prevented from being desorbed. In addition, Ag of the first protective layer 13 can be prevented from being recrystallized when the second protective layer 24 is formed.
By setting the second protective layer 24 to 0.3 μm or more, it is possible to prevent the stabilization layer 28 from being peeled off due to alloying of Cu.

The back surface layer 26 is a layer made of Cu or Cu alloy formed on the back surface 16 c of the laminate 16 on the base material 10 side.
The back layer 26 is electrically connected to the second protective layer 24 via the side layer 25 and the stabilization layer 28.
Further, the back surface layer 26 is bonded to the back surface portion 28 c of the stabilization layer 28 disposed on the back surface 16 c side of the stacked body 16 via the solder layer 29. Since the back surface layer 26 is made of Cu or Cu alloy, it has high adhesiveness with solder. Therefore, it is easily joined to the back surface portion 28 c of the stabilization layer 28.

  As an example, a means for forming the back layer 26 made of Cu will be described. The back layer 26 made of Cu can be formed by sputtering as with the second protective layer 24. The back surface layer 26 is formed by placing a Cu target on the substrate 10 side (back surface 16c side) of the laminate 16 and applying a voltage to the Cu target to discharge the Cu sputtered particles to the back surface 16c of the laminate 16. Can be deposited and performed.

The thickness of the back layer 26 is preferably 0.3 μm or more and 2.1 μm or less.
When an attempt is made to form the back surface layer 26 having a film thickness exceeding 2.1 μm in a single film forming process by sputtering, the heat during film formation is transferred to the oxide superconducting layer 12 and oxygen in the oxide superconducting layer 12 is desorbed. There is a risk of separation. Moreover, peeling of the stabilization layer 28 by Cu alloying can be prevented by making the back surface layer 26 into 0.3 micrometer or more.

  In addition, when performing the film-forming process of the back surface layer 26 in multiple times, the back surface layer 26 exceeding 2.1 micrometers is formed by setting the film thickness in one film-forming process to 2.1 micrometers or less. Also good. In this case, it is preferable to make the thickness of the back surface layer 26 in the range of 10 μm or less in consideration of the cost of the film forming process. The back surface layer 26 is bonded to the end portion of the transverse section of the stabilization layer 28 covering the stacked body 16 in a C shape via the solder layer 29. For this reason, the solder bonding between the back surface layer 26 and the stabilization layer 28 tends to be a starting point of peeling of the stabilization layer 28. By setting the back surface layer 26 to a film thickness exceeding 2.1 μm, peeling due to embrittlement due to alloying of solder and Cu can be prevented more reliably.

The side layer 25 is a layer made of Cu or a Cu alloy formed on the side surface 16b of the laminate 16 on the base material 10 side. The side layer 25 is formed integrally with the second protective layer 24 and the back layer 26.
The side layer 25 is formed at the same time when the second protective layer 24 and the back layer 26 are formed by sputtering. In the formation of the second protective layer 24 by the sputtering method, the sputtered particles (Cu particles) wrap around the side surface 16b of the stacked body 16 and the Cu particles are stacked. Similarly, Cu particles are stacked on the back surface 16c of the stacked body 16 in the formation of the back surface layer 26 by sputtering. This is because the sputtered particles collide with an inert gas (for example, Ar) in the processing container to change the movement direction.
By forming in this way, the side surface layer 25, the second protective layer 24, and the back surface layer 26 integrally surround the transverse section of the multilayer body 16.

The stabilization layer 28 is made of a metal tape arranged in a substantially C-shaped cross section along the second protective layer 24, the side layer 25, and the back layer 26. The stabilization layer 28 is disposed so as to extend from the main surface of the multilayer body 16 to both side surfaces 16b and 16b and reach the back surface 16c. The stabilization layer 28 is bonded to the second protective layer 24, the side surface layer 25, and the back surface layer 26 via the solder layer 29.
The stabilization layer 28 is made of copper, brass (brass, Cu—Zn alloy), a copper alloy such as a Cu—Ni alloy, Ni alloy, stainless steel, or the like, and serves as a bypass for commutating overcurrent generated at the time of an accident. . In addition, the stabilization layer 28 is used to instantaneously suppress an overcurrent that occurs when the oxide superconducting wire 2 is used in a superconducting fault current limiter and a quench occurs and the state is changed to a normal conducting state.

The stabilization layer 28 is a laminate 16 in which the first protective layer 13, the second protective layer 24, the side layer 25, and the back layer 26 are laminated on the surface of the metal tape provided with the solder layer 29 by plating or the like. It can be formed by wrapping and bending the peripheral surface so as to form a substantially C-shaped cross section, melting the solder layer 29 by heating and pressing it with a roll.
The stabilizing layer 28 is disposed on the main surface portion 28a disposed on the oxide superconducting layer 12 side of the stacked body 16, the side surface portion 28b disposed on the side surface 16b side of the stacked body 16, and the back surface 16c side of the stacked body 16. And a back surface portion 28c. The main surface portion 28 a of the stabilization layer 28 is joined to the second protective layer 24 via the solder layer 29. Similarly, the side surface portion 28 b of the stabilization layer 28 is bonded to the side surface layer 25, and the back surface portion 28 c of the stabilization layer 28 is bonded to the back surface layer 26 via the solder layer 29.

  In the oxide superconducting wire 2 of the second embodiment, the stabilization layer 28 is soldered via a second protective layer 24 made of Cu or a Cu alloy. Thereby, the 1st protective layer 13 which consists of Ag or an Ag alloy can control that a solder does not alloy with Ag and becomes embrittled, without contacting with solder, and can prevent exfoliation of stabilization layer 28. .

Further, a Ni-based alloy (for example, Hastelloy) that is generally suitable as a material for the base material 10 is known as a material having low adhesion to solder, and is stable to the base material 10 via the solder layer 29. It was difficult to join the chemical layer 28.
In the oxide superconducting wire 2 of the present embodiment, the outer periphery (especially the back surface 16c) of the laminate 16 has a layer (second protective layer 24, side layer 25, back surface) made of Cu or Cu alloy having good adhesion to the solder. Covered with layer 26). Therefore, the stabilization layer 28 can be brought into close contact with the outer periphery of the cross section of the multilayer body 16 via the solder layer 29 and can improve the airtightness of the oxide superconducting wire 2. Thereby, it can prevent that a water | moisture content permeates into the oxide superconducting layer 12, and can suppress that a superconducting characteristic deteriorates.

  In addition, when using the material with low adhesiveness with solder, such as Ni base alloy (for example, Hastelloy), as the metal material which comprises the stabilization layer 28, adhesiveness with solder is previously attached to the surface of the stabilization layer 28. It is preferable to perform a surface treatment or the like for enhancing the surface.

  In the oxide superconducting wire 2 according to the second embodiment, the side layers 25 and 25 are formed on the two side surfaces 16b and 16b of the multilayer body 16, respectively, and the side portions 28b and 28b of the stabilization layer 28 are interposed via the solder layer 29. It is joined. However, even if the side layers 25 and 25 are not provided and the stabilization layer 28 is not joined to the side surface 16b of the stacked body 16, the back surface 16c of the stacked body 16 is the back surface portion of the stabilization layer 28. What is necessary is just to join with 28c. In this case, the back surface portion 28 c of the stabilization layer 28 is airtightly bonded to the back surface layer 26 formed on the back surface 16 c of the stacked body 16 via the solder layer 29, so that moisture reaches the oxide superconducting layer 12. This can be suppressed.

The oxide superconducting wire 1 (or oxide superconducting wire 2) described above can be used for various superconducting devices. As an example of a superconducting device provided with the oxide superconducting wire 1, a superconducting coil laminate 100 and a superconducting coil 101 will be described with reference to FIGS. 3 (a) and 3 (b).
The superconducting coil 101 shown in FIG. 3B can be formed by winding the oxide superconducting wire 1 (or the oxide superconducting wire 2). Also, the superconducting coil laminate 100 shown in FIG. 3A can be formed by laminating a plurality of superconducting coils 101 and connecting the superconducting coils 101 to each other.
The superconducting coil 101 and the superconducting coil laminated body 100 can generate a strong magnetic force by passing a current through the oxide superconducting wire 1 (or the oxide superconducting wire 2).

(Superconducting fault current limiter)
FIG. 4 shows a superconducting fault current limiter 99 as an embodiment of the present invention.
In the superconducting current limiter 99, the oxide superconducting wire 1 (or the oxide superconducting wire 2) is wound around a winding drum in a plurality of layers to form a superconducting current limiting module 90, and the superconducting current limiting module 90 As a liquid nitrogen container 95 filled with liquid nitrogen 98. Further, the liquid nitrogen container 95 is stored inside a vacuum container 96 that blocks heat from the outside.
The liquid nitrogen container 95 has a liquid nitrogen filling part 91 and a refrigerator 93 in the upper part, and a heat anchor 92 and a hot plate 97 are provided below the refrigerator 93.
The superconducting current limiter 99 has a current lead portion 94 for connecting an external power source (not shown) to the superconducting current limiter module 90.
When the oxide superconducting wire 1 (or oxide superconducting wire 2) is used as the superconducting current limiting module 90 of the superconducting current limiter 99 as described above, the oxide superconducting wire 1 (or oxide superconducting wire 2). The stabilization layer 18 (or the stabilization layer 28) is preferably made of any one of the group consisting of Ni—Cr alloy, Ni alloy, stainless steel, and brass. Thereby, the overcurrent which generate | occur | produces when quenching occurs and it transfers to a normal conducting state can be suppressed instantaneously.

By using the above-described oxide superconducting wire 1 (or oxide superconducting wire 2) for a superconducting device, it is possible to realize a superconducting device having high reliability.
Here, the superconducting device is an oxide other than the superconducting coil 101 and the superconducting coil laminate 100 described based on FIGS. 3A and 3B and the superconducting fault current limiter 99 described based on FIG. It will not specifically limit if it has the superconducting wire 1 (or oxide superconducting wire 2), For example, a superconducting cable, a superconducting motor, a superconducting transformer, a superconducting power storage device etc. can be illustrated.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.
<Test 1>
As test 1, an oxide superconducting wire having the structure shown in FIG. 1 was evaluated.
<Preparation of sample>
First, the surface of a tape-like base material having a width of 10 mm, a thickness of 0.075 mm, and a length of 1000 mm made of Hastelloy C-276 (trade name of Haynes, USA) was polished using alumina having an average particle diameter of 3 μm. Next, the surface of the substrate was degreased and washed with acetone.
Al ₂ O ₃ (diffusion prevention layer; film thickness 100 nm) is formed on the main surface of the base material by sputtering, and Y ₂ O ₃ (bed layer; film thickness 30 nm) is formed thereon by ion beam sputtering. Was deposited.
Next, MgO (metal oxide layer; film thickness: 5 to 10 nm) is formed on the bed layer by ion beam assisted vapor deposition (IBAD method), and 500 nm thick is formed thereon by pulsed laser vapor deposition (PLD method). CeO ₂ (cap layer) was formed. Next, a 2.0 μm thick GdBa ₂ Cu ₃ O _7-x (oxide superconducting layer) was formed on the CeO ₂ layer by the PLD method.
The sample A thus prepared is commonly used in the following sample preparation in Test 1.

(Sample No. 1, No. 2)
For sample A described above, a first protective layer made of Ag was formed on the oxide superconducting layer by sputtering.
Next, oxygen annealing was performed on this sample.
Next, a metal tape having a width of 10 mm, a thickness of 0.075 mm, and a length of 1000 mm made of Cu plated with 2 μm thick Sn on one side was prepared. The metal tape and the sample were overlapped so that the Sn plating and the first protective layer faced each other, and passed through a furnace heated to 280 ° C. As a result, Sn was melted to form a solder layer, and the metal tape and the first protective layer were joined.
Through the above procedure, sample no. 1, no. 2 oxide superconducting wire was obtained. The thickness of the first protective layer is described in Table 1 below.

(Sample No. 3 to No. 9)
For sample A described above, a first protective layer made of Ag was formed on the oxide superconducting layer by sputtering.
Next, oxygen annealing was performed on this sample.
Next, a second protective layer made of Cu was formed on the first protective layer by sputtering for this sample. In the film formation by the sputtering method, the first protective layer is formed by a single film formation process (not formed by a plurality of film formation processes).
Next, a metal tape having a width of 10 mm, a thickness of 0.075 mm, and a length of 1000 mm made of Cu plated with 2 μm on one side was prepared. The metal tape and the sample were overlapped so that the Sn plating and the second protective layer faced each other, and passed through a furnace heated to 280 ° C. Thus, Sn was melted to form a solder layer, and the metal tape and the second protective layer were joined.
Through the above procedure, the sample Nos. Shown in Table 1 in the lower row were used. 3-No. 9 oxide superconducting wire was obtained. About the thickness of a 1st protective layer and a 2nd protective layer, it describes in Table 1 of a back | latter stage collectively.

Sample No. described above 1-No. In the oxide superconducting wire No. 9, the temperature and time of oxygen annealing were changed according to the thickness of the protective layer.
The protective layer having a thickness of 2 μm was subjected to oxygen annealing at 500 ° C. for 10 hours and taken out after 26 hours of furnace cooling. Those having a protective layer thickness of 1 μm (samples No. 2 and No. 5) were subjected to oxygen annealing at 300 ° C. for 15 hours, and were taken out after 20 hours of furnace cooling.

<Evaluation>
(Critical current characteristics)
Sample No. 1-No. Three oxide superconducting wires 9 were prepared, and their critical current values (Ic) were measured using a four-terminal method. Table 1 shows the average values of Ic of the three oxide superconducting wires.

(Peel strength)
Sample No. 1-No. The peel strength of the metal tape was measured with respect to 9 oxide superconducting wire.
The measurement measured the strength at which the metal tape peels by the stud pull peel test. The peel strength was measured by fixing the tip of a 2.7 mm diameter stud pin to the surface of the metal tape with an epoxy resin (adhesive area of the pin tip of 5.72 mm ² ), and attaching the stud pin to the film-forming surface of the wire. The tensile load at the moment when the stress was reduced by pulling in the vertical direction was taken as the peel stress (peel strength).
In the stud pull peel test, measurement was performed at 10 locations for each sample. Table 1 shows the average of the measured values.
The peel strength was measured until the stress reached 30 MPa. In Table 1 below, “> 30” means that peeling did not occur when a stress of 30 MPa was applied, and indicates that the peel strength is 30 MPa or more.

Of the results shown in Table 1, referring to the critical current value Ic, the sample No. The critical current value of the oxide superconducting wire No. 3 is relatively low. Sample No. In the oxide superconducting wire No. 3, a second protective layer having a thickness of 2.2 μm is formed in a film forming process by one sputtering method. For this reason, it is considered that heat was applied to the oxide superconducting layer and the superconducting characteristics were deteriorated.
On the other hand, the deterioration of superconducting properties is not observed in other samples.

Among the results shown in Table 1, referring to the peel strength, sample No. 1, no. 2, No. The peel strength of the oxide superconducting layer 4 is relatively low.
Of these, sample no. 1, no. The oxide superconducting wire No. 2 does not have the second protective layer. When the peeling surface after peeling of these samples was observed, the peeling surface was between the first protective layer and the stabilization layer. From this, it is considered that Ag of the first protective layer and Sn of the solder layer are alloyed to cause embrittlement, and the peel strength is lowered.

  Sample No. Although the oxide superconducting wire No. 4 has the second protective layer, its film thickness is 0.2 μm. When the peeling surface after peeling of this sample was observed, the peeling surface was between the 2nd protective layer and the stabilization layer. From this, it is considered that Cu of the second protective layer and Sn of the solder layer are alloyed to cause embrittlement, and the peel strength is lowered. That is, it was confirmed that the second protective layer is easily embrittled when the second protective layer is less than 0.3 μm.

  Sample No. 3, no. 5-No. In No. 9, the peel strength between the stabilization layer and the first and second protective layers is a value of 30 MPa or more, and the peel strength is relatively high. From this, it was confirmed that the first and second protective layers were not embrittled and the stabilization layer could be prevented from peeling off. That is, it was confirmed that the peel strength of the stabilizing layer can be improved by forming a second protective layer having a thickness of 0.3 μm or more on the first protective layer made of Ag.

<Test 2>
As test 2, an oxide superconducting wire having the structure shown in FIG. 2 was evaluated.
<Preparation of sample>
First, sample A used in Test 1 is prepared. Sample A is commonly used in the following sample preparation in Test 2.

(Sample No. 10)
For sample A described above, Ag was formed to a thickness of 2 μm on the oxide superconducting layer by sputtering.
Subsequently, oxygen annealing treatment was performed at 500 ° C. for 10 hours, and the furnace was taken out after cooling for 26 hours.
Next, this sample was cut with a laser beam and divided into two to obtain a 5 mm-wide wire.
Next, a 6 μm thick Ag film was further formed on the 2 μm thick Ag layer of this wire by sputtering to form a first protective layer having a total thickness of 8 μm.
Subsequently, a 1 μm-thick Ag back surface layer was formed on the back surface of the wire on the base material side by sputtering, again subjected to oxygen annealing at 500 ° C. for 10 hours, and taken out after 26 hours of furnace cooling.
Next, prepare a metal tape with 5 μm thick Sn plating (melting point 230 ° C., solder layer), fold it into a substantially C shape so as to wrap around the outer periphery of the wire, and pass it heated to 280 ° C. A stabilization layer made of a metal tape was formed on the substrate.
Through the above procedure, sample no. Ten oxide superconducting wires were obtained. The material and thickness of each layer are listed in Table 2 below.

(Sample No. 11 to No. 13)
For sample A described above, a first protective layer made of Ag and having a thickness of 2 μm was formed on the oxide superconducting layer by sputtering.
Next, an oxygen annealing treatment was performed at 300 ° C. for 15 hours, and the sample was taken out after 20 hours of furnace cooling.
Next, this sample was cut with a laser beam and divided into two to obtain a 5 mm-wide wire.
Next, a second protective layer made of Cu having a thickness of 1 μm was formed on the main surface of the first protective layer of the wire by sputtering.
Next, a 1 μm-thick back surface layer made of Cu was formed on the back surface of the wire on the base material side by sputtering.
Next, prepare a metal tape with 5 μm thick Sn plating (melting point 230 ° C., solder layer), fold it into a substantially C shape so as to wrap around the outer periphery of the wire, and pass it heated to 280 ° C. A stabilization layer made of a metal tape was formed on the substrate.
Through the above procedure, sample no. 11-No. 13 oxide superconducting wires were obtained. The material and thickness of each layer are listed in Table 2 below.

<Evaluation>
(Room temperature resistance)
Sample No. 10-No. The electrical resistance (room temperature resistance) at room temperature (25 ° C.) of 13 oxide superconducting wires was measured by a four-terminal method. Since the oxide superconducting layer does not exhibit superconducting properties at room temperature, the room temperature resistance is mainly a combined resistance of the first protective layer, the second protective layer, the back layer, the stabilization layer, and the like.
The test results are summarized in Table 3.

Sample No. 10, no. For the 11 oxide superconducting wire, the peel strength of the metal tape (stabilized layer) was measured by the same stud pull peel test as in Test 1.
The measurement was performed on the surface side of the oxide superconducting wire (the side on which the oxide superconducting layer is disposed) and the back surface side (the side on which the base material is disposed).
The test results are summarized in Table 3.

Sample No. 10 and no. The thickness and room temperature resistance of 11 oxide superconducting wires are compared.
The peel strength on the front side and back side is sample No. 11 is higher. From this, it was confirmed that the peel strength can be increased by providing the second protective layer.
Sample No. In the oxide superconducting wire No. 10, a first protective layer (Ag) having a thickness of 8 μm is formed on the surface side. On the other hand, sample no. 11 oxide superconducting wire has a first protective layer (Ag) having a thickness of 2 μm and a second protective layer (Cu) having a thickness of 1 μm formed on the surface side, and the total thickness thereof is 3 μm. By providing the second protective layer, the oxide superconducting wire can be formed thin. Further, since the first protective layer and the second protective layer serve as current paths at room temperature, it is possible to increase the room temperature resistance by reducing their thickness, which is suitable for an oxide superconducting wire for a superconducting current limiter. Can be used.

  Furthermore, sample no. 11 and sample no. 12 and no. Comparison with 13 confirmed that the room temperature resistance was further increased by using a Ni—Cr alloy or brass (brass) as the material constituting the stabilization layer.

Moreover, as shown in Table 2, the Ni—Cr alloy and brass (brass) have a lower thermal conductivity than Cu.
When oxide superconducting wire is used in a superconducting fault current limiter, the thermal conductivity of the stabilization layer is lowered (ie, the heat capacity is increased), so that local heat generation spreads over the entire superconducting fault current limiter. Can be suppressed. Therefore, the region where the superconducting characteristics are destroyed can be made difficult to spread.
By covering the periphery of the oxide superconducting wire with a stabilization layer made of a Ni—Cr alloy or brass (brass), the thermal stability can be improved and the oxide superconducting wire for a superconducting fault current limiter can be suitably used.

  Although the embodiments of the present invention have been described above, the configurations and combinations thereof in the embodiments are examples, and the addition, omission, replacement, and other configurations of the configurations are within the scope not departing from the spirit of the present invention. It can be changed. Further, the present invention is not limited by the embodiment.

DESCRIPTION OF SYMBOLS 1, 2 ... Oxide superconducting wire, 10 ... Base material, 11 ... Intermediate layer, 12 ... Oxide superconducting layer, 12a, 13a, 14a ... Main surface, 13 ... First protective layer, 14, 24 ... Second protective layer 16 ... Laminate, 16b ... Side, 16c ... Back, 18, 28 ... Stabilization layer, 19, 29 ... Solder layer, 25 ... Side layer, 26 ... Back layer, 99 ... Superconducting current limiting device, 100 ... Superconducting coil Laminated body, 101 ... superconducting coil

Claims (7)

A laminated body in which a tape-shaped substrate, an intermediate layer, and an oxide superconducting layer are laminated;
A first protective layer laminated on the main surface of the oxide superconducting layer of the laminate;
A second protective layer laminated on the main surface of the first protective layer;
A stabilizing layer bonded to the main surface of the second protective layer via a solder layer,
The first protective layer is made of Ag or an Ag alloy,
The second protective layer is made of Cu or a Cu alloy, the thickness formed by one film forming process of the second protective layer is 2.1 μm or less, and the final thickness is 0.3 μm or more and 10 μm or less. An oxide superconducting wire.   The oxide superconducting wire according to claim 1, wherein the oxide superconducting layer is formed so as to include a neutral surface in the thickness direction of the entire wire.   It has a back surface layer made of Cu or Cu alloy laminated on the back surface on the base material side of the laminate, and the stabilizing layer is arranged so as to reach the back surface around the side surfaces on both sides from the main surface of the laminate, The oxide superconducting wire according to claim 1, wherein the oxide superconducting wire is bonded to the back surface layer via a solder layer.   The oxide superconducting wire according to any one of claims 1 to 3, wherein the stabilization layer is made of any one of a group consisting of a Ni-Cr alloy, a Ni alloy, stainless steel, and brass.   The superconducting apparatus which has an oxide superconducting wire as described in any one of Claims 1-4. Prepare a laminate in which an intermediate layer and an oxide superconducting layer are formed on a tape-shaped substrate,
A first protective layer forming step of forming a first protective layer made of Ag or an Ag alloy on the main surface of the oxide superconducting layer of the laminate by a sputtering method;
A second protective layer forming step of forming a second protective layer made of Cu or a Cu alloy with a thickness of 0.3 μm or more and 2.1 μm or less on the main surface of the first protective layer;
Forming a stabilization layer by bonding a metal tape to the main surface of the second protective layer via a solder layer,
The manufacturing method of an oxide superconducting wire in which the second protective layer film forming step includes one or more film forming steps, and the film formation is 2.1 μm or less in one film forming step. Before the step of forming the stabilization layer, a back surface layer forming step of forming a back layer made of Cu or Cu alloy by sputtering on the back surface of the laminate on the base material side,
7. In the step of forming the stabilization layer, the metal tape is disposed so as to wrap around the back surface via the side surfaces on both sides from the main surface of the laminate, and is bonded to the back layer via a solder layer. The manufacturing method of the oxide superconducting wire described in 1.

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