JP2012150981A - Oxide superconducting wire material and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconducting wire material capable of suppressing infiltration of water to an oxide superconducting layer and also to provide a method of manufacturing the oxide superconducting wire material.SOLUTION: The method of manufacturing the oxide superconducting wire material includes: a first step of preparing a superconducting laminate 5 formed by laminating a base material 11, an intermediate layer 12, an oxide superconducting layer 13 and a silver layer 14 in this order; and a second step of sandwiching the superconducting laminate 5 from the base material 11 side and the silver layer 14 side by a first metal tape 1 and a second metal tape 2 which are wider than the superconducting laminate 5; and a third step of seam-welding end sections 1a, 2a of the first metal tape 1 and second metal tape 2 in the width direction thereof. At least one of the first metal tape 1 and the second metal tape 2 are made of a resistant-weldable metal material.

Description

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

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

  In the oxide superconducting wire, the stability of the two-layer structure in which a thin silver stabilizing layer is formed on the oxide superconducting layer and a thick stabilizing layer made of a highly conductive metal material such as copper is provided thereon. A structure in which a chemical layer is laminated is employed. The silver stabilizing layer is also provided for the purpose of adjusting fluctuations in the amount of oxygen when the oxide superconducting layer is subjected to oxygen heat treatment, and the copper stabilizing layer is formed from the oxide superconducting layer in a superconducting state. It is provided for the purpose of functioning as a bypass for commutating the current in the oxide superconducting layer when attempting to transition to the normal conducting state.

  As an example of a technique for forming a stabilization layer having a two-layer structure, a thin silver stabilization layer is formed by sputtering on an oxide superconducting layer, and then the entire wire is immersed in a copper sulfate aqueous plating bath to perform electroplating. A technique for forming a copper stabilization layer on a silver stabilization layer is known (see Patent Document 1). In addition, a wire rod provided with a silver stabilization layer on an oxide superconducting layer and a copper stabilization tape are overlapped with solder and passed through a heating / pressurizing roll. A technique for forming a copper stabilization layer is also known (see Patent Document 2).

JP 2007-80780 A JP 2009-48987 A

The RE-123-based oxide superconducting layer having a specific composition is easily deteriorated by moisture, and the oxide superconducting layer is obtained when the wire is stored in an environment with a lot of moisture or when the wire is left in a state where moisture is attached. If moisture penetrates into the film, it becomes a factor of deteriorating superconducting properties.
In the structure in which the copper stabilization layer is formed by plating as in the cited document 1, if there is a defect in the copper plating part, moisture enters from the plating defect part and reaches the oxide superconducting layer. There is a risk of deterioration.
In the technique of forming a copper stabilization layer by laminating a copper stabilization material tape on a silver stabilization layer as in Cited Document 2, there is no problem that a plating defect portion is formed in the copper stabilization layer. . However, since only the upper surface of the silver stabilization layer is protected by the copper stabilization layer, the side surface of the oxide superconducting layer that is easily damaged by moisture is exposed to the outside, and thus during the manufacturing process, etc. There is a risk that superconducting properties may be deteriorated due to the ingress of moisture.

  The present invention has been made in view of the conventional situation as described above, and an object thereof is to provide an oxide superconducting wire capable of suppressing the intrusion of moisture into the oxide superconducting layer and a method for producing the same.

  In order to solve the above problems, the oxide superconducting wire manufacturing method of the present invention includes a first step of preparing a superconducting laminate in which a base material, an intermediate layer, an oxide superconducting layer, and a silver layer are laminated in this order; A second step of sandwiching the superconducting laminate from the base material side and the silver layer side by the first metal tape and the second metal tape wider than the superconducting wire laminate, and the first metal tape and the second metal tape. A third step of seam welding the width direction end of the metal tape is provided, and at least one of the first metal tape and the second metal tape is made of a metal material capable of resistance welding.

In the method of manufacturing an oxide superconducting wire according to the present invention, a superconducting laminate is sandwiched between a first metal tape and a second metal tape, and ends of the first metal tape and the second metal tape are seam welded to continuously join them. It is a configuration. Therefore, the end portions of the first metal tape and the second metal tape can be joined without a gap, and an oxide superconducting wire having a structure in which the entire peripheral surface of the superconducting laminate is shielded from the outside can be manufactured. Therefore, according to the method for manufacturing an oxide superconducting wire of the present invention, it is possible to prevent moisture from entering the oxide superconducting layer and prevent the oxide superconducting layer from being damaged by moisture and deteriorating superconducting characteristics. An oxide superconducting wire can be provided. In addition, by joining the first metal tape and the second metal tape by seam welding, the joint strength of the seam weld portion to be formed is strong, so that an oxide superconducting wire with high mechanical strength can be provided.
Moreover, the manufacturing method of the oxide superconducting wire according to the present invention ensures that at least one of the first metal tape and the second metal tape is made of a metal material that can be resistance welded. Therefore, the end portions of the first metal tape and the second metal tape can be welded by seam welding which is resistance welding.

In the method for producing an oxide superconducting wire according to the present invention, in the second step, the first metal tape made of a resistance-weldable metal material is arranged on the substrate side, and the second metal made of a highly conductive material. It is preferable that a tape is disposed on the silver layer side, and in the third step, the first metal tape is in contact with a roller electrode for seam welding.
In this case, since the second metal tape is made of a highly conductive material, when the oxide superconducting layer attempts to transition from the superconducting state to the normal conducting state, the second metal tape together with the silver layer is combined with the oxide superconducting layer. It functions as a bypass where the current flows. Therefore, an oxide superconducting wire in which the oxide superconducting layer is stabilized can be provided. In addition, since the seam welding is performed in a state where the first metal tape is in contact with the roller electrode for seam welding, the contact portion between the metal tape and the roller electrode is sufficiently heated by resistance heat generation. Two metal tapes can be welded.

In the method for producing an oxide superconducting wire according to the present invention, the first metal tape or the second metal tape may be disposed on the silver layer via a conductive bonding layer.
In this case, the manufactured oxide superconducting wire has a silver layer and a metal tape that are electrically and mechanically joined to each other by the joining layer, and the joining is strengthened. The stabilizing effect is improved.

  In order to solve the above problems, an oxide superconducting wire according to the present invention comprises a substrate, an intermediate layer, an oxide superconducting layer, and a silver layer laminated in this order to form a superconducting laminate, and the superconducting laminate is the base A first metal tape disposed on a material side and wider than the superconducting laminate and sandwiched between a second metal tape disposed on the silver layer side and wider than the superconducting laminate, and the first metal tape and the second metal tape Ends in the width direction of the metal tape are joined by seam welds, and at least one of the first metal tape and the second metal tape is made of a metal material that can be resistance welded.

  In the oxide superconducting wire of the present invention, the superconducting laminate is sandwiched between the first metal tape and the second metal tape, and the end portions of the first metal tape and the second metal tape are continuously joined by the seam welded portion by seam welding. It is the structure which was made. Therefore, the end part of the 1st metal tape and the 2nd metal tape is joined without gap, and the structure where all the peripheral surfaces of the superconducting layered product were shielded from the outside is realizable. With such a configuration, it is possible to prevent moisture from entering the oxide superconducting layer and prevent the oxide superconducting layer from being damaged by moisture and deteriorating superconducting characteristics. In addition, since the first metal tape and the second metal tape are joined by seam welding, the oxide superconducting wire has high joining strength and high mechanical strength. Therefore, for example, even if coil processing is performed for forming a superconducting coil, the joint portion is not broken.

In the oxide superconducting wire of the present invention, the first metal tape is made of a metal material that can be resistance welded, the second metal tape is made of a highly conductive material, and a conductive bonding layer is formed on the silver layer. The second metal tape is preferably arranged.
In this case, since the second metal tape is made of a highly conductive material, when the oxide superconducting layer attempts to transition from the superconducting state to the normal conducting state, the second metal tape together with the silver layer is combined with the oxide superconducting layer. It functions as a bypass where the current flows. Further, since the second metal tape and the silver layer are electrically and mechanically connected by the conductive bonding layer, the bonding between the silver layer and the second metal tape becomes strong and the connection resistance is lowered. The effect of stabilizing the superconductivity can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the oxide superconducting wire which can suppress the penetration | invasion of the water | moisture content to an oxide superconducting layer, and its manufacturing method are provided.

It is a section perspective view showing one embodiment of an oxide superconducting wire concerning the present invention. It is a cross-sectional perspective view which shows an example structure of the superconducting laminated body integrated in the oxide superconducting wire shown in FIG. It is process explanatory drawing for demonstrating the process of one Embodiment of the manufacturing method of the oxide superconducting wire which concerns on this invention. It is sectional drawing which shows other embodiment of the oxide superconducting wire which concerns on this invention. It is a schematic diagram which shows the other example of seam welding. It is a graph which shows the durability test result of the oxide superconducting wire of an Example and Comparative Examples 1 and 2.

Hereinafter, embodiments of an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic sectional view schematically showing one embodiment of an oxide superconducting wire according to the present invention, and FIG. 2 shows an example structure of a superconducting laminate incorporated in the oxide superconducting wire shown in FIG. It is a cross-sectional perspective view.

  The superconducting laminate 5 shown in FIG. 2 is formed by sequentially laminating an intermediate layer 12, an oxide superconducting layer 13, and a silver layer 14 on a long tape-like base material 11. The oxide superconducting wire 10 shown in FIG. 1 is provided with the first metal tape 1 so as to cover the surface of the superconducting laminate 5 on the substrate 11 side, and so as to cover the surface of the superconducting laminate 5 on the silver layer 14 side. The second metal tape 2 is arranged, and the superconducting laminate 5 is sandwiched between the first metal tape 1 and the second metal tape 2. The first metal tape 1 and the second metal tape 2 are wider (longer in the width direction) than the superconducting laminate 5, and the first metal tape 1 and the second metal tape 2 are arranged in the width direction thereof. The end portions 1 a and 2 a on both sides are joined by a seam welded portion 7. The first metal tape 1 is bent at the bent portion 1K from the base material 11 side to the side surface side of the superconducting laminate 5, and is overlapped with the end portion 2a of the planar second metal tape 2 at the end portion 1a. And joined by the seam weld 7.

The base material 11 may be any material that can be used as a base material for ordinary superconducting wires, and is preferably in the form of a long plate, sheet, or tape, and is preferably made of a heat-resistant metal. Among heat resistant metals, an alloy is preferable, and a nickel (Ni) alloy or a copper (Cu) alloy is more preferable. Among them, if it is a commercial product, Hastelloy (trade name, manufactured by Haynes) is suitable, and the amount of components such as molybdenum (Mo), chromium (Cr), iron (Fe), cobalt (Co) is different, Hastelloy B, Any kind of C, G, N, W, etc. can be used. Further, an oriented metal base material in which a texture is introduced into a nickel (Ni) alloy or the like may be used as the base material 11, and the intermediate layer 12 and the oxide superconducting layer 13 may be formed thereon.
What is necessary is just to adjust the thickness of the base material 11 suitably according to the objective, Usually, it is preferable that it is 10-500 micrometers, and it is more preferable that it is 20-200 micrometers. By setting the lower limit value or more, the strength can be further improved, and by setting the upper limit value or less, the critical current density of the overall can be further improved.

The intermediate layer 12 controls the crystal orientation of the oxide superconducting layer 13 and prevents diffusion of the metal element in the base material 11 into the oxide superconducting layer 13. Furthermore, it functions as a buffer layer that alleviates the difference in physical properties (thermal expansion coefficient, lattice constant, etc.) between the base material 11 and the oxide superconducting layer 13, and the material has physical properties that are different from those of the base material 11 and oxide. A metal oxide showing an intermediate value with the superconducting layer 13 is preferable. Specifically, preferred materials for the intermediate layer 12 are Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd _2. Examples thereof include metal oxides such as O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ .
The intermediate layer 12 may be a single layer or a plurality of layers. For example, the layer made of the metal oxide (metal oxide layer) preferably has crystal orientation, and when it is a plurality of layers, the outermost layer (the layer closest to the oxide superconducting layer 13). Preferably have at least crystal orientation.

The intermediate layer 12 may have a multi-layer structure in which a bed layer is interposed on the substrate 11 side. The bed layer has high heat resistance and is used for reducing interfacial reactivity, and is used for obtaining the orientation of a film disposed thereon. Such a bed layer is arranged as necessary, and is made of, for example, yttria (Y ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), or the like. Is done. The bed layer is formed by a film forming method such as a sputtering method, and has a thickness of 10 to 200 nm, for example.

Further, in the present invention, the intermediate layer 12 may have a multi-layer structure in which a diffusion prevention layer and a bed layer are laminated on the base material 11 side. In this case, a diffusion preventing layer is interposed between the base material 11 and the bed layer. The diffusion preventing layer is formed for the purpose of preventing the diffusion of the constituent elements of the substrate 11, and is composed of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ ), rare earth metal oxide, or the like. The thickness is, for example, 10 to 400 nm. Note that since the crystallinity of the diffusion preventing layer is not questioned, it may be formed by a film forming method such as a normal sputtering method.
In this way, by interposing the diffusion preventing layer between the base material 11 and the bed layer, when forming the other layer constituting the intermediate layer 12, the oxide superconducting layer 13 or the like, it is inevitably heated. When receiving a thermal history as a result of the heat treatment, it is possible to effectively suppress a part of the constituent elements of the base material 11 from being diffused to the oxide superconducting layer 13 side through the bed layer. As an example of the case where a diffusion preventing layer is interposed between the base material 11 and the bed layer, a combination using Al ₂ O ₃ as the diffusion preventing layer and Y ₂ O ₃ as the bed layer can be exemplified.

  The intermediate layer 12 may have a multi-layer structure in which a cap layer is further laminated on the metal oxide layer. The cap layer has a function of controlling the orientation of the oxide superconducting layer 13, diffuses the elements constituting the oxide superconducting layer 13 into the intermediate layer 12, and uses a gas and an intermediate used when the oxide superconducting layer 13 is laminated. It has a function of suppressing the reaction with the layer 12 and the like.

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

The thickness of the intermediate layer 12 may be appropriately adjusted according to the purpose, but is usually 0.1 to 5 μm.
When the intermediate layer 12 has a multi-layer structure in which a cap layer is laminated on the metal oxide layer, the thickness of the cap layer is usually 0.1 to 1.5 μm.

The intermediate layer 12 is formed by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, ion beam assisted vapor deposition (hereinafter abbreviated as IBAD); chemical vapor deposition (CVD). ); Coating pyrolysis method (MOD method); lamination can be performed by a known method for forming an oxide thin film such as thermal spraying. In particular, the metal oxide layer formed by the IBAD method is preferable in that the crystal orientation is high and the effect of controlling the crystal orientation of the oxide superconducting layer 13 and the cap layer is high. The IBAD method is a method of orienting crystal axes by irradiating an ion beam at a predetermined angle with respect to a crystal deposition surface during deposition. Usually, an argon (Ar) ion beam is used as the ion beam. For example, the intermediate layer 12 made of Gd ₂ Zr ₂ O ₇ , MgO, or ZrO ₂ —Y ₂ O ₃ (YSZ) can reduce the value of ΔΦ (FWHM: full width at half maximum) that is an index representing the degree of orientation in the IBAD method. Therefore, it is particularly suitable.

The oxide superconducting layer 13 can be widely applied with an oxide superconductor having a generally known composition, such as REBa ₂ Cu ₃ O _y (RE is Y, La, Nd, Sm, Er, Gd, etc. A material made of a material that represents a rare earth element, specifically, Y123 (YBa ₂ Cu ₃ O _y ) or Gd123 (GdBa ₂ Cu ₃ O _y ) can be exemplified. Further, other oxide superconductors, for _{example, Bi 2 Sr 2 Ca n-} 1 Cu n for _{O 4 + 2n + δ} becomes may be used in compositions such as those made of other oxide superconductors having high critical temperatures representative Of course.
The oxide superconducting layer 13 is laminated by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, or electron beam vapor deposition; chemical vapor deposition (CVD); coating pyrolysis (MOD). Among them, the laser vapor deposition method is preferable.
The oxide superconducting layer 13 has a thickness of about 0.5 to 5 μm and preferably a uniform thickness.

The silver layer 14 laminated on the oxide superconducting layer 13 is formed by a film forming method such as a sputtering method, and has a thickness of about 1 to 30 μm.
The reason why the silver layer 14 is provided on the oxide superconducting layer 13 is that silver is highly conductive, has a low contact resistance with the oxide superconducting layer 13, and is compatible with the oxide superconducting layer 13. The point which has the property which makes it difficult to escape oxygen doped from the oxide superconducting layer 13 in the annealing process to dope can be mentioned.

  At least one of the first metal tape 1 and the second metal tape 2 is made of a metal material that can be resistance welded. As a result, the first metal tape 1 and the second metal tape 2 are obtained by performing seam welding in a state where a metal tape made of a metal material that can be resistance welded is in contact with a roller electrode for seam welding, as will be described in detail in a manufacturing method described later. Can be joined, and the seam weld 7 can be formed. As the first metal tape 1 and the second metal tape 2, those previously processed into a long tape shape are used.

As the metal material that can be resistance welded, a conventionally known metal material can be used as a material to be welded by resistance welding, the thermal conductivity is 30 W / (m · K) or less, and the electric resistance is 4 × 10 ^−. A metal material of ⁸ Ω · m or more is preferable. Both the first metal tape 1 and the second metal tape 2 are formed of a material having a thermal conductivity of more than 30 W / (m · K) or an electric resistance of less than 4 × 10 ⁻⁸ Ω · m. If the current is applied from the roller electrode to the metal tape during seam welding, the resistance heat generated by the metal tape is small or the heat generated by the resistance heat is too fast. The metal tape 1 and the second metal tape 2 may not be joined. Therefore, at least one of the first metal tape 1 and the second metal tape 2 from a metal material having a thermal conductivity of 30 W / (m · K) or less and an electric resistance of 4 × 10 ⁻⁸ Ω · m or more. Is preferably formed.

Examples of the metal material that can be resistance welded include nickel alloy and stainless steel. Specifically, for example, SUS301 (thermal conductivity: 16.3 W / (m · K), electric resistance: 7.2 × 10 ⁻⁷ Ω) M), SUS304 (thermal conductivity 16.3 W / (m · K), electrical resistance 7.2 × 10 ⁻⁷ Ω · m), SUS310 (thermal conductivity 14.2 W / (m · K), electrical resistance 9.2 × 10 ⁻⁷ Ω · m), SUS316 (thermal conductivity 16.3 W / (m · K), electrical resistance 7.4 × 10 ⁻⁷ Ω · m), austenitic stainless steel, SUS430 (heat Ferritic stainless steel such as conductivity 26.0 W / (m · K), electric resistance 6.0 × 10 ⁻⁷ Ω · m), SUS403 (thermal conductivity 24.9 W / (m · K), electric resistance 5 .7 × ^{10 -7} Ω · m) martensitic stainless steels such as, in Nell (Special Metals Corporation, trade name: heat conductivity of 15.1W / (m · K), the electric resistance ^{1.0 × 10 -6 Ω · m)} , Hastelloy B (US Haynes Corporation, trade name: heat conductivity 11 .3 W / (m · K), electric resistance 1.4 × 10 ⁻⁶ Ω · m), Hastelloy C (trade name, manufactured by Haynes, USA; thermal conductivity 11.3 W / (m · K), electric resistance 1. Nickel alloys such as 4 × 10 ⁻⁶ Ω · m), Kovar (thermal conductivity: 17.0 W / (m · K), electric resistance: 4.9 × 10 ⁻⁸ Ω · m).

In the superconducting wire 10 of the present embodiment, the first metal tape 1 disposed on the base material 11 side is made of a resistance-weldable metal material, and the second metal tape 2 disposed on the silver layer 14 side is highly conductive. It is preferable to be comprised from a material.
When the second metal tape 2 is made of a highly conductive material, when the oxide superconducting layer 13 is about to transition from the superconducting state to the normal conducting state, the second metal tape 2 together with the silver layer 14 is an oxide superconducting material. It functions as a bypass where the current of the layer 13 commutates. The second metal tape 2 is preferably made of a highly conductive material, which is preferable because the oxide superconducting wire 10 is stabilized.
In addition, when using the oxide superconducting wire 10 for a superconducting fault current limiter, it is preferable that both the 1st metal tape 1 and the 2nd metal tape 2 are comprised from the metal material which can be resistance-welded. This is because the superconducting fault current limiter performs the current operation by utilizing the difference between the conductor electrical resistances in the superconducting state and the normal conducting state, so that the superconducting wire to be used requires a high conductor resistance in the normal conducting state. In this case, the materials constituting the first metal tape 1 and the second metal tape 2 may be the same or different.

As the highly conductive material constituting the second metal tape 2, it is preferable to use a material made of a relatively inexpensive material such as Cu, brass (Cu—Zn alloy), a copper alloy such as a Cu—Ni alloy, and stainless steel. Among them, Cu is preferable because it has high conductivity and is inexpensive.
The thickness of the second metal tape 2 is not particularly limited and can be adjusted as appropriate. However, when the second metal tape 2 is made of a highly conductive material, the thickness is preferably 10 to 300 μm. By setting the lower limit value or more, a higher effect of stabilizing the oxide superconducting layer 13 can be obtained, and by setting the upper limit value or less, the oxide superconducting wire 10 can be thinned.

The thickness of the 1st metal tape 1 is not specifically limited, It can adjust suitably, For example, it is about 10-300 micrometers. When the 2nd metal tape 2 is comprised from the metal material which can be resistance-welded, the thickness is not specifically limited, It can adjust suitably, for example, is about 10-300 micrometers.
The widths of the first metal tape 1 and the second metal tape 2 are not particularly limited, and can be appropriately adjusted according to the width and thickness of the superconducting laminate 5. The widths of the first metal tape 1 and the second metal tape 2 are set larger than the width of the superconducting laminate 6, and the end portions 1a and 2a on both sides of the first metal tape 1 and the second metal tape 2 are seam welds. It is sufficient that the width is such that the superconducting laminate 5 can be accommodated between the first metal tape 1 and the second metal tape 2 in the state where they are joined together.

The width of the first metal tape 1 and the width of the second metal tape 2 may be the same or different. Considering the ease of seam welding in the oxide superconducting wire manufacturing process, when performing parallel seam welding, the width of the metal tape in contact with the roller electrode for seam welding is slightly smaller than the width of other metal tapes. It is preferable to shorten it.
FIG. 1 shows an example in which the width of the first metal tape 1 and the second metal tape 2 is about twice the width of the superconducting laminate 5, but in this example, the vicinity of the seam weld 7 is easily visible. It is drawn exaggeratingly. Actually, it is only necessary to secure a width capable of seam welding. When the oxide superconducting wire 10 is coiled into a superconducting coil, the width of the first metal tape 1 and the second metal tape 2 is reduced in order to suppress a decrease in the proportion of the superconducting laminate 5 in the superconducting coil. It is preferable to set so that it does not become too wide compared to the width of the superconducting laminate 5. As an example, when the width of the superconducting laminate 5 is 5 mm, the width of the first metal tape 1 can be set to 5.5 mm, and the width of the second metal tape 2 can be set to 6 mm.

The second metal tape 2 and the silver layer 14 are preferably laminated via the conductive bonding layer 9. In particular, when the second metal tape 2 is made of the above-described highly conductive material, the second stabilizing layer 2 and the silver layer 14 are electrically and mechanically connected by the conductive bonding layer 9. Since the bonding between the silver layer 14 and the second metal tape 2 becomes strong and the connection resistance is lowered, the effect of stabilizing the oxide superconductor 13 can be improved.
Even when the second metal tape 2 is not composed of a highly conductive material, the superconducting laminate 5 and the second metal tape are obtained by laminating the second metal tape 2 and the silver layer 14 via the bonding layer 9. This is preferable because the bonding structure 2 is strong.
In addition, lamination | stacking with the 1st metal tape 1 and the base material 11 may be via the joining layer, and does not need to be via the joining layer. Further, when a bonding layer is interposed between the first metal tape 1 and the substrate 11, the bonding layer may be either conductive or non-conductive.

The conductive bonding layer 9 is made of a conductive material, and adheres and fixes the second metal tape 2 and the silver layer 14. The conductive bonding layer 9 is made of solder, plating, brazing material, or the like.
The thickness of the bonding layer 9 is not particularly limited and can be adjusted as appropriate. For example, the thickness can be about 2 to 20 μm.
The bonding layer 9 may be formed on the entire surface of the second metal tape 2 on the silver layer side, or may be formed only on a portion in contact with the silver layer 14.

  When the conductive bonding layer 9 is made of solder, a conventionally known solder can be used, for example, Sn—Ag alloy, Sn—Bi alloy, Sn—Cu alloy, Sn—Zn alloy. Lead-free solder such as Pb—Sn alloy solder, eutectic solder, low-temperature solder and the like can be used, and these solders can be used alone or in combination. Among these, it is preferable to use solder having a melting point of 300 ° C. or less. As a result, the second metal tape 2 and the silver layer 14 can be soldered at a temperature of 300 ° C. or lower. Therefore, it is possible to suppress the deterioration of the characteristics of the oxide superconducting layer 13 due to the heat of soldering. it can.

The first metal tape 1 and the second metal tape 2 have end portions 1 a and 2 a on both sides thereof overlapped and seam welded, and are joined by a seam welded portion 7. Seam welding in the present embodiment refers to resistance heat generated in a material to be welded by bringing a pair of roller electrodes into contact with the material to be welded at an appropriate pressure and rotating the roller electrode while energizing the roller electrode. This is a welding method in which welding is continuously performed by heating. Therefore, in the vicinity of the seam welded portion 7 of the oxide superconducting wire 10, a trace pressed by the roller electrode is formed, and the periphery of the seam welded portion 7 has a shape that follows the joint surface with the roller electrode.
When a seam weld 7 is formed by parallel seam welding performed by arranging a pair of tapered roller electrodes on one end 1a and the other end 1a of the first metal tape 1 (FIG. 3 to be described later). (See (b)), traces of a shape following the tapered surface of the tapered roller electrode are formed on the periphery of the seam weld 7. In addition, when the seam weld 7 is formed by seam welding performed by sandwiching a laminated body of the first metal tape 1 and the second metal tape 2 between a pair of roller electrodes (see FIG. 5 described later), seam welding is performed. A trace having a shape following the outer peripheral surface of the roller electrode is formed on the periphery of the portion 7.

  In the oxide superconducting wire 10 of the present embodiment, the superconducting laminate 5 is sandwiched between the first metal tape 1 and the second metal tape 2 which are wider than the superconducting laminate 5. The ends 1a and 2a are continuously joined by a seam weld 7 by seam welding. Therefore, the end portions 1a and 2a of the first metal tape 1 and the second metal tape 2 are joined without a gap, and a structure in which the entire peripheral surface of the superconducting laminate 5 is shielded from the outside can be realized. By adopting such a configuration, it is possible to prevent moisture from entering the oxide superconducting layer 13 and prevent the oxide superconducting layer 13 from being damaged by moisture and degrading the superconducting characteristics. Moreover, since the 1st metal tape 1 and the 2nd metal tape 2 are joined by seam welding, it becomes the oxide superconducting wire 10 with strong joint strength and high mechanical strength. Therefore, for example, even if coil processing is performed for forming a superconducting coil, the joint portion is not broken.

  In the oxide superconducting wire 10 of the present embodiment, the second metal tape 2 laminated on the silver layer 14 is previously processed into a tape shape. Therefore, unlike the case where the stabilization layer is formed by plating as in the conventional superconducting wire, no pinhole such as a plating defect portion is formed in the second metal tape 2, and thus the superconducting laminate 5 Can be completely shielded from the outside, and moisture does not enter the oxide superconducting layer 13 to deteriorate the superconducting characteristics.

As in the oxide superconducting wire 10 of this embodiment, as a structure in which the superconducting laminate is sandwiched and protected by two metal tapes, a structure in which both ends of the two metal tapes are soldered and joined is also possible. Conceivable. However, in the case of a structure in which two metal tapes are joined by solder, if the wire is exposed to a high temperature environment above the melting point of the solder for some reason in the wire manufacturing process or processing process, the solder will melt. There is a possibility that moisture enters from the gap formed between the two metal tapes and the oxide superconducting layer 13 is deteriorated.
On the other hand, in the oxide superconducting wire 10 of the present embodiment, the superconducting laminate 5 is sandwiched between the first metal tape 1 and the second metal tape 2, so that both sides of the first metal tape 1 and the second metal tape 2 are sandwiched. The end portions 1a and 2a are superposed and joined by a seam welded portion 7 by seam welding. Therefore, even when the oxide superconducting wire 10 is exposed to a high temperature environment for some reason in the manufacturing process or processing step of the oxide superconducting wire 10, the seam joint 7 is firmly joined and the joining structure is maintained. Therefore, moisture does not enter the oxide superconducting layer 13 and the superconducting characteristics are not deteriorated.

Next, an embodiment of a method for manufacturing the oxide superconducting wire 10 according to the present invention will be described with reference to the drawings.
FIG. 3 is a process explanatory diagram for explaining a process of an embodiment of the method for manufacturing an oxide superconducting wire according to the present invention.
The manufacturing method of the oxide superconducting wire according to this embodiment includes a first step of preparing a superconducting laminate 5 in which a base material 11, an intermediate layer 12, an oxide superconducting layer 13, and a silver layer 14 are laminated in this order; A second step of sandwiching the superconducting laminate 5 from the substrate 11 side and the silver layer 14 side by the first metal tape 1 and the second metal tape 2 which are wider than the superconducting wire laminate 5, and the first metal tape 1 and the second metal tape 2 A third step of seam welding the width direction end portions 1a and 1b of the metal tape 2 is provided.

First, the above-described long oxide superconducting laminate 5 is prepared (first step).
Next, the first metal tape 1 and the second metal tape 2 in the form of a long tape having the material, width and thickness described above are prepared, and superconducting lamination is performed on the second metal tape 2 as shown in FIG. The body 5 is laminated with the silver layer 14 facing down, and the first metal tape 1 is laminated on the substrate 11 of the superconducting laminate 5 (second step). As a result, the superconducting laminate 5 is sandwiched between the first metal tape 1 and the second metal tape 2.

  Here, the first metal tape 1 and the second metal tape 2 are wider than the superconducting laminate 5 (long in the width direction), and the first metal tape 1 and the second metal tape are used. 2 are arranged so that the end portions 1 a and 2 a on both sides are located outside the superconducting laminate 5. Further, the width of the first metal tape 1 and the width of the second metal tape 2 may be the same or different. Considering the ease of seam welding in the third step described later, when parallel seam welding is performed as shown in FIG. 3B, the width of the metal tape in contact with the roller electrode for seam welding is set to other metal. It is preferable to make it slightly shorter than the width of the tape. In the example shown in FIG. 3, it is preferable that the width of the first metal tape 1, which is a metal tape located above, is slightly shorter than the width of the second metal tape 2.

In the second step, when the second metal tape 2 having a conductive bonding layer 9 such as solder, plating or brazing material formed on the surface thereof is used in advance, on the silver layer 14 of the superconducting laminate 5. The silver layer 14 and the second metal tape 2 are electrically and mechanically bonded by the bonding layer 9 by passing a heating / pressurizing roll in a state where the second metal tape 2 is laminated on the bonding layer 9. It is preferable to join. Thereby, in particular, when the second metal tape 2 is made of the above-described highly conductive material, the bonding between the silver layer 14 and the second metal tape 2 becomes strong and the connection resistance is lowered. The effect of stabilizing the layer 13 can be improved.
Even when the second metal tape 2 is not composed of a highly conductive material, the superconducting laminate 5 and the second metal tape are obtained by laminating the second metal tape 2 and the silver layer 14 via the bonding layer 9. This is preferable because the bonding structure 2 is strong.
In some cases, the first metal tape 1 having a surface on which a bonding layer capable of bonding to the base material 11 is formed is used, and the first metal tape 1 and the base material 11 are interposed via the bonding layer. And may be joined in advance.

In the second step, the first metal tape 1 made of a metal material that can be resistance welded is disposed on the base material 11 side of the superconducting laminate 5, and the superconducting laminate 5 is made of a highly conductive material on the silver layer 14 side. It is preferable to arrange the second metal tape 2 made. In this case, the second metal tape 2 made of a highly conductive material is laminated on the silver layer 14 of the oxide superconducting wire 10 to be manufactured. Therefore, in the oxide superconducting wire 10, when the oxide superconducting layer 13 attempts to transition from the superconducting state to the normal conducting state, the second metal tape 2 made of a highly conductive material together with the silver layer 14 becomes an oxide. This is preferable because it can function as a bypass through which the current of the superconducting layer 13 commutates and the oxide superconducting wire 10 is stabilized.
In addition, when using the oxide superconducting wire 10 for a superconducting fault current limiter, it is preferable that both the 1st metal tape 1 and the 2nd metal tape 2 are comprised from the metal material which can be resistance-welded.

  Next, as shown in FIG. 3A, a laminate in which the second metal tape 2, the superconducting laminate 5, and the first metal tape 1 are laminated is a pedestal (shown in the figure) with the second metal tape 2 side down. Set on (Omitted). Next, as shown in FIG. 3B, a pair of tapered roller electrodes 20 and 20 made of a highly conductive material such as copper are provided on one end 1a and the other end 1a of the first metal tape 1. Are placed opposite each other. Here, the roller electrode 20 is a roller having a tapered portion 20a on the peripheral surface and having a tapered cross section so as to increase the diameter from one to the other. The roller electrode 20 is shown in FIG. 3B, with the roller electrode 20 having a smaller diameter on the superconducting laminate 5 side and the larger diameter on the end 1a side of the first metal tape 1. Arrange as follows. In FIG. 3B, the inclination of the tapered portion 20a of the roller electrode 20 is exaggerated, but actually, the inclination of the tapered portion 20a is gentle, as shown in FIG. 3C. The one having a shape that can form the seam weld 7 having the structure is used.

  Subsequently, the taper portion 20a of the roller electrode 20 is brought into contact with the end portion 1a of the first metal tape 1 with an appropriate pressure, and the first metal tape 1 is bent toward the second metal tape 2 to bend the bent portion 1K. And the end 1a of the first metal tape 1 and the end of the second metal tape 2 overlap each other. Then, while applying a pulse current to the seam welding roller electrodes 20, 20, the roller electrodes 20, 20 are rotated along the longitudinal direction of the superconducting laminate 5 to cause the first metal tape 1 and the second metal tape 2. Seam welding (parallel seam welding) is performed on the end portions 1a and 2a on both sides (third step). A conventionally known seam welding apparatus can be used.

In the present embodiment, as described above, at least one of the first metal tape 1 and the second metal tape 2 is made of a metal material that can be resistance welded, but the seam welding in the third step can be resistance welding. It is necessary to carry out in a state where a metal tape made of a metal material is in contact with the roller electrode 20.
When seam welding is performed in a state in which a metal tape made of a metal material that can be resistance welded does not contact the roller electrode 20, even when an electric current is applied from the roller electrode 20 to the metal tape, the resistance heat generation at the metal tape is small, or resistance Since the heat release is too fast, the metal tape is not sufficiently heated, and the first metal tape 1 and the second metal tape 2 are not joined.

  In the manufacturing method of the oxide superconducting wire according to the present embodiment, when the first metal tape 1 and the second metal tape 2 are made of a metal material that can be resistance welded, the laminate shown in FIG. Can also be seam welded. However, in the case where the second metal tape 2 is made of the above-described highly conductive material, in particular, Cu or the like has good conductivity and low electrical resistance and is not suitable for resistance welding. Therefore, in this case, it is necessary to use the first metal tape 1 made of a resistance-weldable metal material and perform seam welding in a state where the first metal tape 1 is in contact with the roll electrode 20 as shown in FIG. is there.

  In the seam welding in the third step, the current value applied to the roller electrode 20 may be appropriately adjusted depending on the material and thickness of the first metal tape 1 and the second metal tape 2. Further, the pressurization by the roller electrode 20 may be appropriately adjusted according to the material and thickness of the first metal tape 1 and the second metal tape 2. For example, when a stainless steel tape having a thickness of 50 μm is used as the first metal tape 1 and a copper tape having a thickness of 50 μm is used as the second metal tape 2, a current value of about 100 to 500 A is applied while pressing at a pressure of about 10 to 20 MPa. The seam welding can be performed by applying the current. The rotational traveling speed of the roller electrode 20 can also be adjusted as appropriate.

  Through the above steps, as shown in FIG. 3C, the end portions 1a, 2a on both sides of the first metal tape 1 and the second metal tape 2 are joined by the seam welded portion 7, and the superconducting laminate 5 is joined to the first metal tape. The oxide superconducting wire 10 covered with the first and second metal tapes 2 can be manufactured.

  The oxide superconducting wire manufacturing method of the present embodiment includes a superconducting laminate 5 sandwiched between a first metal tape 1 and a second metal tape 2, and ends 1a on both sides of the first metal tape 1 and the second metal tape 2, 2a is seam-welded and continuously joined. Therefore, the end portions 1a and 2a of the first metal tape 1 and the second metal tape 2 can be joined without gaps, and an oxide superconducting wire having a structure in which the entire peripheral surface of the superconducting laminate 5 is shielded from the outside is manufactured. it can. Therefore, according to the manufacturing method of the oxide superconducting wire of the present embodiment, it is possible to prevent moisture from entering the oxide superconducting layer 13 and prevent the oxide superconducting layer 13 from being damaged by moisture and deteriorating superconducting characteristics. An oxide superconducting wire that can be provided can be provided. Also, by joining the first metal tape 1 and the second metal tape 2 by seam welding, the joint strength of the seam welded portion 7 to be formed is strong, so that an oxide superconducting wire having high mechanical strength can be provided.

  The manufacturing method of the oxide superconducting wire of this embodiment uses metal tapes 1 and 2 that have been processed into a tape shape in advance. Therefore, since the metal tapes 1 and 2 do not have a defect such as a pinhole, the manufactured oxide superconducting wire can completely shield the superconducting laminate 5 from the outside, and the oxide superconducting layer 13 has moisture. Does not penetrate and the superconducting properties are not deteriorated.

As mentioned above, although the embodiment of the oxide superconducting wire of the present invention and the manufacturing method thereof has been described, in the above embodiment, each part of the oxide superconducting wire is an example, and is appropriately changed without departing from the scope of the present invention. It is possible.
For example, in the above embodiment, the oxide superconducting wire 10 having a structure in which the first metal tape 1 arranged on the base material 11 side of the superconducting laminate 5 is bent to the side surface side of the superconducting laminate 5 is illustrated. The invention is not limited to this example. FIG. 4 is a sectional view showing another embodiment of the oxide superconducting wire according to the present invention. In FIG. 4, the same code | symbol is attached | subjected to the component same as the oxide superconducting wire 10 of the said embodiment, and description is abbreviate | omitted.

In the oxide superconducting wire 10B shown in FIG. 4, the second metal tape 2 disposed on the silver layer 14 side of the superconducting laminate 5 is bent toward the side surface of the superconducting laminate 5, and the planar first metal tape 1 is formed. It differs from the oxide superconducting wire 10 of the above embodiment in that it is seam welded to the end 1a.
In the oxide superconducting wire 10B having such a configuration, as in the oxide superconducting wire 10 of the first embodiment, the entire peripheral surface of the oxide superconducting laminate 5 including the oxide superconducting layer 13 is shielded from the outside. Since the configuration can be realized, it is possible to prevent moisture from entering the oxide superconducting layer 13 and to prevent the oxide superconducting layer 13 from being damaged by moisture and deteriorating superconducting characteristics.

When the second metal tape 2 is made of a resistance-weldable metal material, the oxide superconducting wire 10B of the present embodiment has a superconducting laminate 5 and the first metal tape 1 in the manufacturing process shown in FIG. The laminated body in which the second metal tape 2 is laminated can be manufactured by making the laminate upside down and performing seam welding in a state where the second metal tape 2 is in contact with the roller electrode 20.
In the oxide superconducting laminate 10B of the present embodiment, when the second metal tape 2 is made of the above-described highly conductive material and the first metal tape 1 is made of a metal material that can be resistance welded, it is shown in FIG. Oxide superconducting wire 10B can be manufactured by performing such seam welding.
The seam welding method shown in FIG. 5 is a pair of roller electrodes so that the end 1a of the first metal tape 1 and the end 2a of the second metal tape 2 are overlapped, and the ends 1a and 2a are sandwiched from both sides. In this method, 20B and 20B are arranged to face each other and welded. In the case of the welding method shown in FIG. 5, if at least one of the first metal tape 1 and the second metal tape 2 is made of a metal material capable of resistance welding, the first metal tape 1 and the second metal tape. The two end portions 1 a and 2 a can be welded and joined by the seam welded portion 7. Of course, the seam welding method shown in FIG. 5 can be used in the third step of the manufacturing method of the oxide superconducting wire of the above embodiment.

  The oxide superconducting wire of the present invention is not limited to the oxide superconducting wires 10 and 10B described above, and both the first metal tape 1 and the second metal tape 2 are bent toward the side surface of the superconducting laminate 5. It may be a structure. In that case, an oxide superconducting wire can be manufactured using the seam welding method shown in FIG.

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

"Example"
An intermediate layer of Gd ₂ Zr ₂ O ₇ (GZO) having a thickness of 1.2 μm by an IBAD method on a metal substrate made of Hastelloy C276 (trade name, manufactured by Haynes, USA) having a width of 10 mm and a thickness of 0.1 mm. Further, a cap layer having a composition of CeO _{2 having a} thickness of 1.0 μm was formed on the intermediate layer by the PLD method. Next, an oxide superconducting layer having a composition of GdBa ₂ Cu ₃ O _7-x having a thickness of 1.0 μm is formed on the cap layer by a PLD method, and further a thickness of 10 μm is formed on the oxide superconducting layer by a sputtering method. A silver layer was formed. By cutting the obtained laminate along the longitudinal direction, a superconducting laminate having a width of 5 mm, a length of 10 m, and a critical current value Ic0 = 100 A at a liquid nitrogen temperature (77 K) was produced.

Next, a stainless steel tape having a thickness of 50 μm and a width of 5.5 mm (thermal conductivity: 16.3 W / (m · K), electric resistance: 7.2 × 10 ⁻⁷ Ω · m) was used as the first metal tape, As a second metal tape, a 5 μm thick tin plating (melting point: 230 ° C., bonding layer) formed on one side is a 50 μm thick, 6.0 mm wide copper tape (thermal conductivity 394 W / (m · K), electrical resistance. 1.7 × 10 ⁻⁸ Ω · m), the superconducting laminate formed above is laminated on the copper plating tin plating with the silver layer facing down, and heated at 240 ° C. to bond the copper tape and the silver layer. After being joined via the joining layer, a stainless steel tape was laminated on the base material of the superconducting laminate as shown in FIG.
Subsequently, as shown in FIG. 3 (b), both ends of the copper tape and the stainless steel tape in the width direction are welded by parallel seam welding to obtain an oxide superconducting wire having a structure shown in FIG. 3 (c). Produced. Seam welding was performed under the following conditions.
Material of roller electrode: copper, current value: 500 A, welding time 10 ms, cooling time 30 ms, welding speed 5 mm / s, applied pressure: 100 g.

  The prepared oxide superconducting wire was held in an atmosphere of temperature 121 ° C., humidity 100%, 2 atm for 100 hours, and then the superconducting characteristics of the oxide superconducting wire were measured. The critical current value at liquid nitrogen temperature (77K) Ic was 100 A, and the superconducting characteristics were not deteriorated.

“Comparative Example 1”
A superconducting laminate having a critical current value Ic0 = 100 A at a width of 5 mm, a length of 10 m, and a liquid nitrogen temperature (77 K) was produced in the same manner as in the example.
Next, the superconducting laminate produced was immersed in a copper sulfate aqueous plating bath, and a copper plating layer having a thickness of 20 μm was formed on the outer periphery of the superconducting laminate by electroplating to produce an oxide superconducting wire.

  The prepared oxide superconducting wire was held in an atmosphere of 121 ° C., 100% humidity and 2 atmospheres for 72 hours, and then the superconducting properties of the oxide superconducting wire were measured. The critical current value at liquid nitrogen temperature (77K) was measured. Ic was 10 A, and the superconducting characteristics were deteriorated. When the plating layer of the oxide superconducting wire of Comparative Example 1 was observed, there was a portion where a pinhole defect portion was formed, and it was thought that the oxide superconducting layer deteriorated due to moisture entering from the defect portion.

"Comparative Example 2"
A superconducting laminate having a critical current value Ic0 = 100 A at a width of 5 mm, a length of 10 m, and a liquid nitrogen temperature (77 K) was produced in the same manner as in the example.
Next, an oxide superconducting wire was produced by soldering and bonding a copper tape having a thickness of 100 μm and a width of 5 mm onto the silver layer of the superconducting laminate produced.

  The superconducting properties of the oxide superconducting wire were measured after holding the prepared oxide superconducting wire for 48 hours in an atmosphere of a temperature of 121 ° C., a humidity of 100%, and 2 atmospheres. The critical current value at a liquid nitrogen temperature (77K) was measured. Ic was 0 A, and the superconducting characteristics were deteriorated. In the oxide superconducting wire of Comparative Example 2, since the side surface of the oxide superconducting layer was exposed, it was considered that moisture entered from this exposed portion and the oxide superconducting layer deteriorated.

The durability test results of the oxide superconducting wires of Examples and Comparative Examples 1 and 2 are shown in FIG. FIG. 6 is a plot of the ratio Ic / Ic0 of the critical current value Ic after the test to the critical current value Ic0 before the test against the test time. It shows that durability is so high that vertical axis | shaft Ic / Ic0 is near 1.0.
From the results of FIG. 6, it is clear that the oxide superconducting wire of the example according to the present invention can suppress the penetration of moisture into the oxide superconducting layer.

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

  DESCRIPTION OF SYMBOLS 1 ... 1st metal tape, 1a ... End part, 2 ... 2nd metal tape, 2a ... End part, 5 ... Superconducting laminated body, 7 ... Seam weld part, 9 ... Joining layer, 10, 10B ... Oxide superconducting wire, DESCRIPTION OF SYMBOLS 11 ... Base material, 12 ... Intermediate | middle layer, 13 ... Oxide superconducting layer, 14 ... Silver layer, 20, 20B ... Roller electrode.

Claims (5)

  A first step of preparing a superconducting laminate in which a base material, an intermediate layer, an oxide superconducting layer, and a silver layer are laminated in this order; and a first metal tape and a second metal tape that are wider than the superconducting wire laminate A second step of sandwiching the superconducting laminate from the base material side and the silver layer side, and a third step of seam welding the widthwise ends of the first metal tape and the second metal tape, At least one of 1 metal tape and the said 2nd metal tape consists of a metal material which can be resistance-welded, The manufacturing method of the oxide superconducting wire characterized by the above-mentioned. In the second step, the first metal tape made of a resistance-weldable metal material is arranged on the base material side, and the second metal tape made of a highly conductive material is arranged on the silver layer side,
The method for producing an oxide superconducting wire according to claim 1, wherein in the third step, the first metal tape is in contact with a roller electrode for seam welding.   3. The method of manufacturing an oxide superconducting wire according to claim 1, wherein the first metal tape or the second metal tape is disposed on the silver layer via a conductive bonding layer.   A substrate, an intermediate layer, an oxide superconducting layer, and a silver layer are laminated in this order to constitute a superconducting laminate, and the superconducting laminate is arranged on the substrate side and is wider than the superconducting laminate. Between the first metal tape and the second metal tape in a seam welded portion. The first metal tape and the second metal tape are joined by a seam welded portion. An oxide superconducting wire, wherein at least one of the first metal tape and the second metal tape is made of a metal material that can be resistance welded.   The first metal tape is made of a metal material that can be resistance welded, the second metal tape is made of a highly conductive material, and the second metal tape is disposed on the silver layer via a conductive bonding layer. The oxide superconducting wire according to claim 4, wherein

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