JP2016091880A - Connection structure of superconductive wire, superconductive wire, and connection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive wire which has high connection strength and is adequately conducted; a connection structure thereof; and a connection method thereof.SOLUTION: In a connection structure 100 in which two superconductive wires 10 having a superconductor layer 3 formed on one face side of a substrate 1 through an intermediate layer 2 are connected to each other on mutual connection ends. the superconductor layers of the two superconductive wires are aligned along the same plane, and the substrates of the two superconductive wires are aligned along the same plane. The connection structure 100 includes a first intermediate superconductor layer 32 which is grown and formed in any range between the end surface on the connection end side of one superconductive wire to the end surface of the connection end side of the other superconductive wire. Any one of the positions of the end surfaces on the connection end side of the substrate of the two superconductive wires is out-of-range of the first intermediate superconductor layer in the longitudinal direction of the two superconductive materials.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a superconducting wire connecting structure, a superconducting wire, and a connecting method.

In recent years, for example, YBCO-based (yttrium-based) high-temperature oxide superconductors have attracted attention as oxide superconductors whose critical temperature (Tc) is higher than the liquid nitrogen temperature (about 77 K).
In this high-temperature oxide superconducting wire, a superconducting conductor layer is formed by depositing an oxide superconducting film on a substrate of a long and flexible metal or by depositing an oxide superconducting film on a single crystal substrate. Things are known. An intermediate layer may be provided between the substrate and the superconducting conductor layer as necessary.

The YBCO-based high-temperature oxide superconductor has a property that current easily flows along a so-called ab plane (CuO ₂ plane), and current hardly flows in the c-axis direction perpendicular thereto. A superconducting wire made of a YBCO-based high-temperature oxide superconductor is formed so that the longitudinal direction of the wire is parallel to the ab surface and the superconducting conductor layer is along the ab surface.
Therefore, when connecting the superconducting wire, if the superconducting conductor layers of one superconducting wire and the superconducting conductor layer of the other superconducting wire are overlapped and connected with the planes of the superconducting conductors facing each other, the connection of the superconducting wires In the portion, current flows in the c-axis direction, and it becomes difficult for current to flow, so that the superconducting characteristics are deteriorated.

For this reason, in patent document 1, the superconducting conductor layer of the connection end part side of a mutual superconducting wire was removed, the end surfaces of the connection end part of a base material were connected, and the superconducting conductor layer of each superconducting wire was removed. A connection method has been proposed in which a superconducting conductor layer is newly grown on the portion.
Moreover, in patent document 2, the front-end | tips of superconducting wire to connect are arrange | positioned apart, the board | substrate is overlapped and connected so that it may oppose the superconducting conductor layer of each superconducting wire, and it opposes the superconducting conductor layer of this board | substrate. There has been proposed a connection method in which a superconducting conductor layer is newly formed in a portion between the superconducting conductor layer and the superconducting conductor layer, and the superconducting wires are connected to each other.

  According to these connection methods, since the superconducting conductor layer of the superconducting wire connected to each other and the newly formed superconducting conductor layer are connected side by side on the same plane, current can flow along the ab plane. The superconducting characteristics can be improved.

JP 2001-319750 A Japanese Patent Laying-Open No. 2005-063695

  However, in the connection method of Patent Document 1, if a step is generated between the connected base materials, the superconducting conductor layer is liable to grow poorly on the connected base materials. The connection work has been very difficult.

Moreover, although the connection method of patent document 2 does not produce the problem of the level | step difference of a base material, since the base materials of the superconducting wire were not connected directly, there existed a problem that a mutual connection strength became low.
In addition, in this connection method, since the position to be formed on the superconducting conductor layer is close to the end of the base material, there has also been a problem that the superconducting characteristics of the superconducting conductor layer deteriorate due to metal diffusion from the end of the base material. .

  An object of the present invention is to provide a superconducting wire connecting structure, a superconducting wire, and a connecting method that have high connection strength and allow a current to flow well.

The invention described in claim 1
A connection structure in which two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer are connected to each other at connection ends,
The superconducting conductor layers of the two superconducting wires are arranged along the same plane, and the base materials of the two superconducting wires are arranged along the same plane,
A first intermediate formed in any range between the end surface on the connection end portion side of the superconducting conductor layer of one of the superconducting wires and the end surface on the connection end portion side of the superconducting conductor layer of the other superconducting wire. With a superconducting conductor layer,
The positions of the end surfaces of the two superconducting wires on the connecting end side of the base material are both outside the range of the first intermediate superconducting conductor layer in the longitudinal direction of the two superconducting wires. .

The invention described in claim 2 is the superconducting wire connecting structure according to claim 1,
The base material and the base material of the base material are in any range between the end surface on the connection end portion side of the superconducting conductor layer of one of the superconducting wires and the end surface on the connection end portion side of the superconducting conductor layer of the other superconducting wire. A second intermediate superconducting conductor layer comprising a superconducting conductor layer of the first connecting wire provided with a superconducting conductor layer formed on one side,
With respect to the longitudinal direction of the two superconducting wires, the positions of the end faces of the connection end portions of the superconducting conductor layers of the two superconducting wires and the first connecting wire are both based on the two superconducting wires. It is different from the position of the end surface on the connection end side of the material.

The invention according to claim 3 is the connection structure of the superconducting wire according to claim 1,
Between the base materials of the two superconducting wires, other base materials arranged along the same plane as these base materials are interposed,
In the longitudinal direction of the two superconducting wires, the positions of the end faces on both sides of the other base material are different from the positions of the end faces of the superconducting conductor layer.

The invention described in claim 4 is the superconducting wire connecting structure according to claim 1,
With respect to the longitudinal direction of the two superconducting wires, the position of the end face of the intermediate layer of one of the superconducting wires is on the other superconducting wire side than the position of the end face on the connecting end side of the base material of the two superconducting wires It is located in.

The invention according to claim 5 is the superconducting wire connecting structure according to claim 4,
In the longitudinal direction of the two superconducting wires, there is a portion where the thickness of the intermediate layer is thicker than other portions within a predetermined range including the position of the end surface of the superconducting conductor layer of at least one of the superconducting wires. And

The invention according to claim 6 is the connection structure of the superconducting wire according to any one of claims 1 to 5,
With respect to the longitudinal direction of the two superconducting wires, at least the position of the end surface of the connecting end portion of the superconducting conductor layer of the two superconducting wires and the position of the end surface of the connecting end portion of the base material of the two superconducting wires are at least 1 [μm] or more apart.

The invention according to claim 7 is a superconducting wire,
A connection structure according to any one of claims 1 to 6 is provided.

The invention according to claim 8 is a method for connecting a superconducting wire,
It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A first removal step of removing a part or all of the superconducting conductor layer at the connecting end of the two superconducting wires in the thickness direction;
A joining step for joining the connection ends of the base materials of the two superconducting wires; and
A first connecting wire provided with a base material and a superconducting conductor layer formed on one side of the base material in a portion where the superconducting conductor layer is removed, the superconducting conductor layer of the two superconducting wires and the A first disposing step of disposing the superconducting conductor layer of the first connecting wire so as to be positioned on the same plane;
The second superconducting conductor layer of the two superconducting wire rods is connected between the end surface of each of the connecting end portions and the end surfaces of the second intermediate superconducting conductor layer composed of the superconducting conductor layer of the first connecting wire rod. And a first forming step of newly forming one intermediate superconducting conductor layer.

The invention according to claim 9 is a method for connecting a superconducting wire,
It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A second removal step of removing the base material at the connection end of the two superconducting wires;
An intermediate layer of a second connecting wire comprising a base material and an intermediate layer located on one side of the base material is in contact with the intermediate layer of the two superconducting wires exposed by the second removal step, and A second disposing step of disposing the second connecting wire so that the base material of the two superconducting wires and the base material of the second connecting wire are located on the same plane;
A first intermediate superconducting conductor layer is newly formed between an end surface of the superconducting conductor layer of one of the superconducting wires and an end surface of the other superconducting wire on the side of the connecting end of the superconducting conductor layer. And a second forming step.

The invention according to claim 10 is a method of connecting a superconducting wire,
It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A third removal step of removing part or all of the superconducting conductor layer at the connection end of the one superconducting wire in the thickness direction;
A fourth removal step of removing the base material of the connection end of the other superconducting wire;
A third disposing step of disposing the two superconducting wires so that the superconducting conductor layer or the exposed intermediate layer of the one superconducting wire remains and the exposed intermediate layer of the other superconducting wire are polymerized. When,
A third intermediate superconducting conductor layer is formed between the end face on the connection end side of the superconducting conductor layer of one of the superconducting wires and the end face on the connection end side of the superconducting conductor layer of the other superconducting wire. And a forming step.

The invention according to claim 11 is a method of connecting a superconducting wire.
It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A fifth removal step of removing part or all of the superconducting conductor layer at the connection end of one of the superconducting wires in the thickness direction;
A sixth removal step of removing the base material at the connection end of the other superconducting wire;
In one of the superconducting wires, the two superconducting wires are placed in a state where the superconducting conductor layer is partially or entirely removed, with the other superconducting wire facing the one superconducting wire. A fourth arrangement step for arranging the superconducting conductor layer of the wire to be located on the same plane;
And a fourth forming step of newly forming another superconducting conductor layer between the end faces on the connecting end side of the superconducting conductor layers of the two superconducting wires.

  In the said invention, it becomes possible to provide the connection structure of the superconducting wire which can flow an electric current favorably, the connection method, and a superconducting wire with said structure.

It is a perspective view of a superconducting wire. 2A to 2C are cross-sectional views showing a connection method for forming a connection structure of superconducting wires according to the first embodiment. It is a diagram which shows the temperature dependence of the self-diffusion coefficient of Ni. 4A to 4C are cross-sectional views showing a connection method for forming a connection structure for a superconducting wire according to the second embodiment. FIGS. 5A to 5C are cross-sectional views showing a connection method for forming a connection structure for a superconducting wire according to a third embodiment. 6 (A) to 6 (C) are cross-sectional views showing a connection method for forming a superconducting wire connection structure according to the fourth embodiment.

[First embodiment]
Hereinafter, a preferred first embodiment for carrying out the present invention will be described with reference to the drawings. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples. In the drawings, the same or corresponding elements are denoted by the same reference numerals as appropriate, and repeated descriptions are omitted as appropriate. Furthermore, it should be noted that the drawings are schematic, and dimensional relationships between elements may differ from actual ones. Even between the drawings, there are cases in which portions having different dimensional relationships and ratios are included.

[Superconducting wire]
FIG. 1 is a perspective view of a superconducting wire according to the first embodiment of the present invention.
As shown in FIG. 1, a superconducting wire 10 is placed on one main surface (hereinafter referred to as a film-forming surface 11) in the thickness direction of a substrate 1 for superconducting film formation (hereinafter referred to as “base material 1”). Layer 2 and oxide superconducting conductor layer 3 are laminated in this order. That is, the superconducting wire 10 has a laminated structure including a base material 1, an intermediate layer 2, and an oxide superconducting conductor layer 3 (hereinafter referred to as “superconducting conductor layer 3”).

As the substrate 1, a tape-like low magnetic metal substrate or ceramic substrate is used. As the material of the metal substrate, for example, a metal such as Co, Cu, Cr, Ni, Ti, Mo, Nb, Ta, W, Mn, Fe, and Ag, which is excellent in strength and heat resistance, or an alloy thereof is used. . In particular, from the viewpoint of excellent corrosion resistance and heat resistance, it is preferable to use Ni-based alloys such as Hastelloy (registered trademark) and Inconel (registered trademark), or Fe-based alloys such as stainless steel.
Various ceramics may be arranged on these various metal materials. Moreover, as a material of the ceramic substrate, for example, MgO, SrTiO ₃ , yttrium stabilized zirconia, or the like is used. In addition, sapphire may be used as a base material.

The film formation surface 11 is a substantially smooth surface, and for example, the surface roughness of the film formation surface 11 is preferably 10 nm or less.
The surface roughness is the arithmetic average roughness Ra in the “amplitude average parameter in the height direction” of the surface roughness parameter defined in JISB-0601-2001.

The intermediate layer 2 is a layer for realizing, for example, high biaxial orientation in the superconducting conductor layer 3. For such an intermediate layer 2, for example, physical characteristic values such as a coefficient of thermal expansion and a lattice constant indicate intermediate values between the substrate 1 and the superconductor constituting the superconducting conductor layer 3.
The intermediate layer 2 may have a single layer structure or a multilayer structure. In the case of a multilayer structure, the number and types of layers are not limited, but a bed layer containing amorphous Gd ₂ Zr ₂ O _7-δ (δ is an oxygen non-stoichiometric amount), Al ₂ O _3, Y ₂ O _3, or the like. And a forced alignment layer formed by IBAD (Ion Beam Assisted Deposition) method including crystalline MgO and the like, and an LMO layer including LaMnO _{3 + δ} (δ is an oxygen non-stoichiometric amount) are sequentially stacked. May be. Further, a cap layer containing CeO ₂ or the like may be further provided on the LMO layer.
The thickness of each of the above layers is 30 nm for the LMO layer, 40 nm for the MgO layer for forced alignment layer, 7 nm for the Y ₂ O ₃ layer for bed, and 80 nm for the Al ₂ O ₃ layer. These numerical values are only examples.

A superconducting conductor layer 3 is laminated on the surface of the intermediate layer 2. The superconducting conductor layer 3 preferably contains an oxide superconductor, particularly a copper oxide superconductor. As the copper oxide superconductor, REBa ₂ Cu ₃ O _7-δ (hereinafter referred to as RE superconductor) as a high-temperature superconductor is preferable. Note that RE in the RE-based superconductor is a single rare earth element or a plurality of rare earth elements such as Y, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu. Further, δ is an oxygen non-stoichiometric amount and is, for example, 0 or more and 1 or less, and is preferably closer to 0 from the viewpoint that the superconducting transition temperature is high. The oxygen non-stoichiometric amount may be less than 0, that is, take a negative value when high-pressure oxygen annealing or the like is performed using an apparatus such as an autoclave.

Further, the superconducting conductor layer 3 may be formed with a stabilization layer covering the surface (the surface opposite to the intermediate layer 2). Moreover, you may cover the whole surface of the base material 1, the intermediate | middle layer 2, and the superconducting conductor layer 3 of a laminated state not only by the surface of the superconducting conductor layer 3, but by the stabilization layer.
The stabilization layer may have a single layer structure or a multilayer structure. In the case of a multilayer structure, the number and types of the layers are not limited, but a silver stabilization layer made of silver and a copper stabilization layer made of copper may be laminated in order.

[Connection structure of superconducting wire]
This embodiment shows a superconducting wire connecting structure 100, a superconducting wire having the superconducting wire connecting structure 100, and a superconducting wire connecting method. The “superconducting wire having the superconducting wire connection structure 100” refers to a superconducting wire having the first and second superconducting wires 10A and 10B connected by the connection structure 100.

As shown in FIG. 2C, the superconducting wire connecting structure 100 according to the present embodiment is connected by a connecting method described later in a state where the connecting ends of the first and second superconducting wires 10A and 10B are abutted to each other. It is formed by doing. However, the superconducting wire connecting structure 100 is not limited to one formed by a connecting method described later, and may be formed by another connecting method.
The first and second superconducting wires 10A and 10B have the same structure as the superconducting wire 10, and the same reference numerals as those of the superconducting wire 10 are used for the layers 1 to 3.
Here, as an example, the thickness of the substrate 1 is approximately 50 μm, the thickness of the intermediate layer 2 is approximately 200 nm, and the thickness of the superconducting conductor layer 3 is approximately 1 μm. This value is an example, and is not limited to these values and can be arbitrarily changed as long as the intermediate layer 2 is thinner than the superconducting conductor layer 3.

  In this connection structure 100, the base materials 1 and 1 of the connection ends of the first and second superconducting wires 10A and 10B are joined together by welding, and the connection ends of the first and second superconducting wires 10A and 10B are joined. The superconducting conductor layers 3 and 3 are connected to each other via the superconducting conductor layer 3C of the first connecting wire 10C.

That is, the base materials 1 and 1 and the intermediate layers 2 and 2 of the respective superconducting wires 10A and 10B are in a state in which the end surfaces 12, 12, 21, and 21 on the connection end side face each other. , 1 are joined together by welding at the end faces 12, 12 on the connection end side.
In addition, the superconducting conductor layers 3 and 3 on the connection end side of each superconducting wire 10A and 10B are predetermined in the longitudinal direction L (hereinafter simply referred to as “longitudinal direction L”) of each connected superconducting wire 10A and 10B. The first connecting wire 10C is disposed in the portion where the superconducting conductor layers 3 and 3 are removed from each of the superconducting wires 10A and 10B.

In the first connecting wire 10C, a superconducting conductor layer 3C is formed on one side of the substrate 1C via an intermediate layer 2C. The base material 1C, intermediate layer 2C, and superconducting conductor layer 3C of the first connecting wire 10C are made of the same material as the base material 1, intermediate layer 2, and superconducting conductor layer 3 of the superconducting wire 10, respectively.
Superconducting conductor layer 3C is not the same material as superconducting conductor layer 3, but may be the same type of superconducting conductor layer. Here, the same kind of superconducting conductor layer means a material of the same system as the superconducting conductor layer 3. For example, when the superconducting conductor layer 3 is a Y (yttrium) -based high-temperature copper oxide superconductor, the superconducting conductor layer 3C may be a Y-based high-temperature copper oxide superconductor, and the substances are completely matched. Not necessary. When the superconducting conductor layer 3C is formed from the same material, the material of the intermediate layer 2C may be appropriately changed according to the superconducting conductor layer 3C.
The thicknesses of the base material 1C, the intermediate layer 2C and the superconducting conductor layer 3C of the first connecting wire 10C are the same as those of the base material 1, the intermediate layer 2 and the superconducting conductor of the first and second superconducting wires 10A and 10B described above. Although it is desirable to make it equal to the thickness of the layer 3, a different thickness may be selected as long as they are approximate.

The first connecting wire 10C is disposed such that the superconducting conductor layer 3C side faces the superconducting wires 10A and 10B, and thereby the first connecting wire 10C and the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B are connected to the first connecting wire 10C. The superconducting conductor layer 3C of the wire rod 10C is in a state of being arranged on the same plane parallel to the longitudinal direction L. That is, the superconducting conductor layer 3C of the first connecting wire 10C functions as a “second intermediate superconducting conductor layer”.
Note that “aligned on the same plane” is sufficient if there is a portion where the connecting end faces partially overlap in the thickness direction. The same shall apply hereinafter. It is more preferable that the superconducting conductor layers 3 and 3 and the superconducting conductor layer 3C are arranged on the same straight line. Moreover, it is more preferable that the base materials 1 and 1 described later are arranged on the same straight line.
The length of the first connecting wire 10C in the longitudinal direction L is shorter than the total length of the removed portions of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B. ing. Accordingly, the end faces 31C and 31C at both ends of the superconducting conductor layer 3C of the first connecting wire 10C are connected to the connecting end portions of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B. It is spaced apart from the end surfaces 31 and 31 (refer FIG. 2 (B)). For this reason, between the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A and the one end surface 31C of the superconducting conductor layer 3C of the first connecting wire 10C, and the second superconducting wire. Between the end surface 31 on the connection end side of the 10B superconducting conductor layer 3 and the other end surface 31C of the superconducting conductor layer 3C of the first connecting wire 10C, the first intermediate superconducting conductor layers 32 and 32, respectively. Is formed by growth formation of a superconducting material.
The first intermediate superconducting conductor layers 32 and 32 are also formed of the same or the same kind of superconducting material as the superconducting conductor layer 3.

Thereby, the superconducting conductor layers 3 and 3 of the respective superconducting wires 10A and 10B, the superconducting conductor layer 3C of the first connecting wire 10C, and the first intermediate superconducting conductor layers 32 and 32 are on the same plane parallel to the longitudinal direction L. It is in a state of being lined up. It is more preferable that the superconducting conductor layers 3 and 3, the superconducting conductor layer 3C, and the first intermediate superconducting conductor layers 32 and 32 are arranged on the same straight line.
Further, the end surfaces 31, 31 on the connecting end side of the superconducting conductor layers 3, 3 of each superconducting wire 10A, 10B are joined to one end surfaces 321, 321 of the first intermediate superconducting conductor layers 32, 32, respectively. The end faces 31C and 31C of the superconducting conductor layer 3C of the connecting wire 10C are joined to the other end faces 321 and 321 of the first intermediate superconducting conductor layers 32 and 32, and the end faces 31, 31, 31C, 31C, 321 and 321 are All are generally perpendicular to the longitudinal direction L.
As a result, a current can flow along the ab surface from the superconducting conductor layer 3 of the first superconducting wire 10A to the superconducting conductor layer 3 of the second superconducting wire 10B, and a good superconducting state can be formed.

Also, the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L, the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B, The positions of the end surfaces 31C and 31C at both ends of the superconducting conductor layer 3C of the first connecting wire 10C do not coincide with the positions of the end surfaces 12 and 12 on the connecting end side of the base materials 1 and 1, and are sufficiently It is separated.
For this reason, the end surfaces 31, 31 on the connection end side of the superconducting conductor layers 3, 3 of the superconducting wires 10A, 10B, the end surfaces 321, 321 on both ends of the first intermediate superconducting conductor layers 32, 32, and the first connection. The influence of metal diffusion from the end face on the connection end side of each of the base materials 1 and 1 to the end faces 31C and 31C at both ends of the superconducting conductor layer 3C of the wire rod 10C is sufficiently reduced.

FIG. 3 is a diagram showing the temperature dependence of the self-diffusion coefficient of general Ni as a main material contained in the substrate 1. In FIG. 3, the horizontal axis represents Tu / T (Tu is the melting point of Ni, T is the heating temperature), and the vertical axis represents the self-diffusion coefficient. Since the heating temperature in the operation of forming the connection structure 100 of the superconducting wire is less than 1000 ° C., when the heating temperature is set to 1000 ° C. and the self-diffusion coefficient is obtained according to the relationship of FIG. Ni diffuses to a distance of about 1 [μm].
Actually, since the heating temperature is less than 1000 ° C., the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L from the end surface 12 on the connection end portion side of the substrate 1; The distance between the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B and the end surfaces 31C and 31C at both ends of the superconducting conductor layer 3C of the first connecting wire 10C is 1 [μm] or more. If so, it is possible to sufficiently reduce the influence of diffusion from the substrate 1. These end faces 31, 31, 31C, 31C are all sufficiently separated from the end face 12 on the connection end portion side of the base material 1 in the longitudinal direction L by more than 1 [μm]. Can be reduced.

  Moreover, as for the two 1st intermediate | middle superconducting conductor layers 32 and 32, as for all, the position of the end surfaces 12 and 12 by the side of the connection end part of the base materials 1 and 1 of 1st and 2nd superconducting wire 10A and 10B is, The longitudinal direction L is outside the range of the first intermediate superconducting conductor layers 32 and 32.

[Connection method of superconducting wire]
A method for connecting the superconducting wires forming the connection structure 100 will be described with reference to FIGS. 2 (A) to 2 (C).
First, as shown in FIG. 2 (A), the superconducting conductor layers 3 and 3 at the connection ends of the first and second superconducting wires 10A and 10B have a predetermined length in the longitudinal direction L and all in the thickness direction. It removes and the surface of the intermediate | middle layers 2 and 2 is exposed (1st removal process). These removals are performed by mechanical polishing, chemical polishing (for example, etching treatment), or a combination thereof.

Note that the predetermined length for removing the superconducting conductor layers 3 and 3 in the longitudinal direction L is such that the two first intermediate superconducting conductor layers 32 and 32 formed in this removal range are individually formed. The first and second superconducting wires 10A and 10B may have a length that can be individually stored in the heating tank, for example, several tens [cm]. Moreover, when not heating 1st and 2nd superconducting wire 10A, 10B separately, you may shorten.
Further, some, but not all, of the superconducting conductor layers 3 and 3 in the thickness direction may be removed and partially left. When a part of each superconducting conductor layer 3, 3 is left, first intermediate superconducting conductor layers 32, 32 to be described later are formed on the remaining superconducting conductor layers 3, 3.
Further, it is desirable that the surface roughness of the portion where the superconducting conductor layers 3 and 3 are removed be sufficiently small. For example, the surface roughness (centerline average roughness Ra) is preferably 50 nm or less, and more preferably 10 nm or less.

  Further, as shown in FIG. 2 (B), the connection end of the base material 1 of the first superconducting wire 10A and the connection end of the base material 1 of the second superconducting wire 10B are opposed to each other and the connection ends of each other. The end faces 12 and 12 on the part side are joined by welding (joining process). Thus, the first superconducting wire 10A and the second superconducting wire 10B are connected with sufficient strength through the base materials 1 and 1.

  Furthermore, as shown in FIG. 2 (B), the first connecting wire 10C is placed in the first and second superconducting conductor layers 3 and 3 from the first and second superconducting wires 10A and 10B. The superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B and the superconducting conductor layer 3C of the first connecting wire 10C are arranged on the same plane (first arranging step).

  In addition, before this 1st connection wire 10C is arrange | positioned, the end surface of the both ends of the base material 1C is previously removed by the etching process etc. only in the longitudinal direction L by length e. The removal length e is preferably 1 [μm] or more. By removing both ends of the substrate 1C, in the formation of the first intermediate superconducting conductor layers 32 and 32 on both sides of the first connecting wire 10C, the influence of metal diffusion from the end surfaces of both ends of the substrate 1C is affected. It becomes possible to reduce.

Further, when the superconducting conductor layer 3C of the first connecting wire 10C is disposed in the removal range of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B, the superconducting conductor layer 3C and Bonding by heating may be performed between the intermediate layers 2 and 2 of the first and second superconducting wires 10A and 10B.
In addition, even when a part of the superconducting conductor layers 3 and 3 is left in the thickness direction in the removal range of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B, the first connection The superconducting conductor layer 3C of the wire rod 10C and the remaining superconducting conductor layers 3 and 3 may be joined by heating.

  Next, as shown in FIG. 2C, the end surfaces 31, 31 on the connection end side of the superconducting conductor layers 3, 3 of the first and second superconducting wires 10A, 10B and the first connecting wire. First intermediate superconducting conductor layers 32, 32 are newly formed between the end faces 31C, 31C on both sides of the 10C superconducting conductor layer 3C (first forming step).

The first intermediate superconducting conductor layers 32 and 32 are formed by the MOD method (Metal Organic Deposition method / Organic metal deposition method). That is, the MOD liquid is applied to the locations where the first intermediate superconducting conductor layers 32 and 32 are formed. This MOD liquid contains, for example, RE (rare earth elements such as Y (yttrium), Gd (gadolinium), Sm (samarium), and Ho (holmium)), Ba, and Cu in a ratio of about 1: 2: 3. Acetylacetonate MOD solutions are used.
And the temporary baking process for removing the organic component contained in the apply | coated MOD liquid, and the main baking process for forming the 1st intermediate | middle superconducting conductor layers 32 and 32 by epitaxial growth are predetermined pressure environment. Implemented below.
As a specific example, in the preliminary firing step, the first intermediate superconducting conductor layers 32 and 32 are heat-treated at a temperature range of 400 ° C. or higher and 500 ° C. or lower. It is desirable to heat-treat the portions where the conductor layers 32 and 32 are formed in a temperature range of 750 ° C. or higher and 830 ° C. or lower.

  The first forming step is not limited to the MOD method, and any known publicly known method that enables the formation of a Y-based superconducting conductor layer, such as a chemical vapor deposition method (CVD method) or a laser vapor deposition method (PLD method). A method may be used.

In addition, after the first intermediate superconducting conductor layers 32 and 32 are formed by the first forming step, the first intermediate superconducting conductor layers 32 and 32 and the superconducting conductor layer 3C of the first connecting wire 10C are formed. In addition, it is desirable to perform oxygen annealing treatment for doping oxygen on the connection end portions of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B. This oxygen annealing treatment is performed by connecting the first intermediate superconducting conductor layers 32 and 32 to the superconducting conductor layer 3C of the first connecting wire 10C and the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B. The end portion is accommodated in an oxygen atmosphere, and is carried out in a predetermined heating environment.
As a specific example, an oxygen annealing target part is placed in an oxygen atmosphere in a temperature range of 350 ° C. or higher and 500 ° C. or lower, and oxygen doping is performed under this condition.

  Further, after the oxygen annealing step, silver is deposited on the surface of each superconducting conductor layer 3, 3, 3C, 32, 32 of the connection structure 100 or the entire surface of the connection structure 100, or a silver paste is applied. A silver stabilization layer may be formed by baking after coating, and a stabilization layer forming step of forming a copper stabilization layer thereon by electrolytic plating may be added.

  By each of these steps, the superconducting wire connecting structure 100 is formed.

[Technical effects of the first embodiment]
In the superconducting wire connecting structure 100, the superconducting conductor layers 3, 3, 3C of the first and second superconducting wires 10A, 10B and the first connecting wire 10C are arranged along the same plane, and the first and second superconducting wires 10A, 10B are arranged along the same plane. The base materials 1 and 1 of the two superconducting wires 10A and 10B are arranged along the same plane. Further, in the superconducting wire connecting structure 100, the end surfaces 31 and 31 on the connecting end side of the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B and the first side in the longitudinal direction L of the connected superconducting wires 10A and 10B. Connection of the end surfaces 31C and 31C of the superconducting conductor layer 3C of the connecting wire 10C (which coincides with the positions of the four end surfaces 321 of the first intermediate superconducting conductor layers 32 and 32) and the base materials 1 and 1 The positions of the end faces 12 and 12 on the end side are both separated by 1 [μm] or more.
By these, the end surfaces 31, 31, 31C, 31C of the respective superconducting conductor layers 3, 3, 3C can all be separated from the end surface on the connecting end side of the base material 1, 1 that can cause metal diffusion such as Ni, The influence of metal diffusion in the base materials 1 and 1 can be reduced, and the connection structure 100 can be energized with sufficiently reduced electrical resistance with good superconducting characteristics.
In addition, the connection structure 100 can sufficiently increase the superconducting critical current density between the first superconducting wire 10A and the second superconducting wire 10B, and maintain a superconducting state well even at a large current. Is possible.

  Further, in the superconducting wire connecting structure 100, the first connecting wire 10C is disposed at the positions of the end surfaces 12 and 12 on the connecting end side of the bases 1 and 1 of the superconducting wires 10A and 10B. Since it is not necessary to form the superconducting conductor layer so as to straddle the boundary of 1, the formation of the first intermediate superconducting conductor layer 32 is possible even if the base materials 1, 1 are not accurately aligned in the thickness direction. Does not affect the membrane. For this reason, it becomes possible to connect the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B satisfactorily, and to reduce the burden of forming the connection structure 100.

Moreover, in the connection structure 100 of the superconducting wire, the connection ends of the base materials 1 and 1 of the superconducting wires 10A and 10B are joined, so that the connection strength of the connection structure 100 can be improved.
Also, a first intermediate between the end surfaces 31 and 31 of the superconducting conductor layers 3 and 3 of each superconducting wire 10A and 10B and the end surfaces 31C and 31C of the superconducting conductor layer 3C of the first connecting wire 10C. Since the superconducting conductor layers 32 and 32 are formed, the oxygen annealing after the film formation is favorably performed unlike the case where the film is formed inside the deep dent, for example, between the substrates. Is possible.
Moreover, as for the two 1st intermediate | middle superconducting conductor layers 32 and 32, as for all, the position of the end surfaces 12 and 12 by the side of the connection end part of the base materials 1 and 1 of 1st and 2nd superconducting wire 10A and 10B is, The longitudinal direction L is outside the range of the first intermediate superconducting conductor layers 32 and 32. For this reason, the first intermediate superconducting conductor layers 32 and 32 can be satisfactorily formed on a smooth surface without a step, and the respective superconducting conductor layers 3, 3, and 3C can be satisfactorily connected.

  Further, since the superconducting wire connecting structure 100 is formed by the first removing step, the joining step, the first arranging step, and the first forming step, the connecting structure 100 can be formed more easily. It becomes possible.

[Second Embodiment]
FIG. 4 shows a superconducting wire connecting structure 100D according to the second embodiment. About this connection structure 100D, about the structure same as the connection structure 100 mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

[Connection structure of superconducting wire]
The present embodiment shows a superconducting wire connecting structure 100D and a superconducting wire connecting method 100D and a superconducting wire connecting method.
As shown in FIG. 4, the superconducting wire connecting structure 100D according to the present embodiment is connected by a connecting method described later in a state in which the connecting ends of the first and second superconducting wires 10A and 10B are in contact with each other. It is formed. However, the superconducting wire connecting structure 100 </ b> D is not limited to the connection method described below, and may be formed by other connection methods.

In the connection structure 100D, the connection end portions of the first and second superconducting wires 10A and 10B are connected via the second connection wire 10D.
As for 2nd connecting wire 10D, intermediate | middle layer 2D is formed in the single side | surface side of base material 1D. The base material 1D and the intermediate layer 2D of the second connecting wire 10D are formed of the same material as the base material 1 and the intermediate layer 2 of the superconducting wire 10, respectively.

In each of the superconducting wires 10A and 10B, the base materials 1 and 1 at the connection end are removed in a predetermined length in the longitudinal direction L, and the intermediate layers 2 and 2 of the superconducting wires 10A and 10B exposed thereby The intermediate layer 2D of the second connecting wire 10D is in close contact with each other, and the end surfaces 12 and 12 on the connecting end side of each of the substrates 1 and 1 and both ends of the substrate 1D of the second connecting wire 10D. End faces 12D and 12D are joined by welding.
In addition, the length in the longitudinal direction L of the second connecting wire 10D is longer than the total removal length of the base materials 1 and 1 at the connecting end portions of the respective superconducting wires 10A and 10B. There is a gap between the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the superconducting wire 10A and the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B. A first intermediate superconducting conductor layer 32D is formed in this gap by growing a superconducting material. The first intermediate superconducting conductor layer 32D is formed of the same or the same kind of superconducting material as the superconducting conductor layer 3.
With these structures, the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B and the first intermediate superconducting conductor layer 32D are arranged on the same plane parallel to the longitudinal direction L. Further, the base materials 1 and 1 of the superconducting wires 10A and 10B and the base material 1D of the second connecting wire 10D are also arranged on the same plane parallel to the longitudinal direction L. It is more preferable that the superconducting conductor layers 3 and 3 and the first intermediate superconducting conductor layer 32D are on the same straight line. Moreover, it is more preferable that the base materials 1, 1, 1D are on the same straight line.
Further, the end faces 31, 31 on the connection end side of the superconducting conductor layers 3, 3 of the superconducting wires 10A, 10B are joined to the end faces 321D, 321D of the first intermediate superconducting conductor layer 32D, and the end faces 31, 31, 321D are joined. , 321D are generally perpendicular to the longitudinal direction L.
As a result, a current can flow along the ab surface from the superconducting conductor layer 3 of the first superconducting wire 10A to the superconducting conductor layer 3 of the second superconducting wire 10B, and a good superconducting state can be formed.

Further, the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L and the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B are These do not coincide with the positions of the end surfaces 12 and 12 on the connection end side of the base materials 1 and 1, and are sufficiently separated from each other by 1 [μm].
For this reason, each base material 1 with respect to the end surfaces 31 and 31 on the connection end side of the superconducting conductor layers 3 and 3 of each superconducting wire 10A and 10B and the end surfaces 321D and 321D on both ends of the first intermediate superconducting conductor layer 32D. The influence of metal diffusion from the 1 and 1D end faces 12 and 12D is sufficiently reduced.

  In addition, the first intermediate superconducting conductor layer 32D is arranged such that the positions of the end faces 12, 12 on the connection end side of the bases 1, 1 of the first and second superconducting wires 10A, 10B are both in the longitudinal direction L. This is outside the range of the first intermediate superconducting conductor layer 32D.

[Connection method of superconducting wire]
A method for connecting the superconducting wires forming the connection structure 100D will be described with reference to FIGS. 4 (A) to 4 (C).
First, as shown in FIG. 4A, the base materials 1 and 1 at the connection ends of the first and second superconducting wires 10A and 10B are removed in a predetermined length in the longitudinal direction L and in the thickness direction. Then, the surfaces of the intermediate layers 2 and 2 are exposed (second removal step). These removals are performed by mechanical polishing, chemical polishing (for example, etching treatment), or a combination thereof.

Further, as shown in FIG. 4B, the connection end of the base material 1 of the first superconducting wire 10A and the connection end of the base material 1 of the second superconducting wire 10B are opposed to each other to remove the second. The second connecting wire 10D is arranged so that the intermediate layer 2D is in contact with each of the intermediate layers 2 and 2 exposed in the process, and the base materials 1 and 1 and the base material 1D are aligned on the same plane along the longitudinal direction L. It arrange | positions between the connection end part of 10 A of one superconducting wire, and the connection end part of 10B of 2nd superconducting wire (2nd arrangement | positioning process).
At this time, the end surfaces 12 and 12 of the first and second superconducting wires 10A and 10B on the connection end portion side of the substrates 1 and 1 and the end surfaces 12D and 12D of the substrate 1D of the second connecting wire 10D and Are joined individually by welding. Thus, the first superconducting wire 10A, the second superconducting wire 10B, and the second connecting wire 10D are coupled with sufficient strength through the bases 1, 1, 1D.

By the second arrangement step, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B are positioned on the same plane along the longitudinal direction L.
And as shown in FIG.4 (C), it is between the end surfaces 31 and 31 by the side of the connection end part of each superconducting conductor layer 3 and 3 of 1st and 2nd superconducting wire 10A, 10B, and it is 2nd connection. First intermediate superconducting conductor layer 32D is formed on the upper surface of intermediate layer 2D of wire rod 10D (second forming step).
The intermediate layer 2D of the second connecting wire 10D has a sufficiently small surface roughness (for example, the center line average roughness Ra is 50 nm or less, more preferably 10 nm or less). desirable.

The formation of the first intermediate superconducting conductor layer 32D is performed by the MOD method. The details of the MOD method are the same as the formation of the first intermediate superconducting conductor layer 32 of the first embodiment.
The first intermediate superconducting conductor layer 32D is not limited to the MOD method, and any known method capable of forming a Y-based superconducting conductor layer such as a CVD method or a PLD method may be used.

Also, in the case of the first intermediate superconducting conductor layer 32D, after its formation, oxygen annealing treatment is performed in the same manner as in the case of the first intermediate superconducting conductor layer 32, and a stabilization layer forming step is added. May be.
Through these steps, a superconducting wire connection structure 100D is formed.

[Technical effects of the second embodiment]
In the superconducting wire connecting structure 100D, the superconducting conductor layers 3 and 3 and the first intermediate superconducting conductor layer 32D of the first and second superconducting wires 10A and 10B are arranged along the same plane, and the first and second The base materials 1 and 1 of the superconducting wires 10A and 10B and the base material 1D of the first connecting wire 10D are arranged along the same plane.
In the superconducting wire connecting structure 100D, the end surfaces 31, 31 on the connecting end side of the superconducting conductor layers 3, 3 of the superconducting wires 10A, 10B in the longitudinal direction L of the first and second superconducting wires 10A, 10B. (They coincide with the positions of the two end faces 321D of the first intermediate superconducting conductor layer 32D) and the positions of the end faces 12 and 12 on the connecting end side of the substrates 1 and 1 (these are the first positions) The connecting wire 10D is disposed at a distance of 1 [μm] from the end surfaces 12D and 12D of the base 1D.
Accordingly, the superconducting wire connecting structure 100D also reduces the influence of metal diffusion on each of the superconducting conductor layers 3, 3, and 32D in the same way as the superconducting wire connecting structure 100, and has sufficient superconducting characteristics and sufficient electric resistance. It is possible to reduce the power supply.
In addition, the above connection structure 100D can sufficiently increase the superconducting critical current density between the first superconducting wire 10A and the second superconducting wire 10B, and maintain a superconducting state well even at a large current. Is possible.

  In the superconducting wire connecting structure 100D, the first intermediate superconducting conductor layer 32D is formed on the surface of the intermediate layer 2D of the second connecting wire 10D. Even if it is not aligned with accuracy, the film formation of the first intermediate superconducting conductor layer 32D is not affected. For this reason, it becomes possible to connect the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B satisfactorily, and to reduce the burden of forming the connection structure 100D.

In the superconducting wire connecting structure 100D, the connection ends of the base materials 1 and 1 of the superconducting wires 10A and 10B and the base material 1D of the second connecting wire 10D are joined. It is possible to improve.
In addition, since the first intermediate superconducting conductor layer 32D is formed between the end surfaces 31 and 31 on the connecting end side of the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B, for example, the base material and the base material Unlike the case where a film is formed inside a deep dent, such as between, the oxygen annealing after the film formation can be performed satisfactorily.
In addition, the first intermediate superconducting conductor layer 32D is arranged such that the positions of the end faces 12, 12 on the connection end side of the bases 1, 1 of the first and second superconducting wires 10A, 10B are both in the longitudinal direction L. This is outside the range of the first intermediate superconducting conductor layer 32D. For this reason, the first intermediate superconducting conductor layer 32D can be satisfactorily formed on a smooth surface without a step, and the respective superconducting conductor layers 3 and 3 can be satisfactorily connected.

  Moreover, in the connection structure 100D of the superconducting wire, in the longitudinal direction L, the range from the end surface 12 on the connection end portion side of the substrate 1 of the first superconducting wire 10A to the end surface 31 on the connection end portion side of the superconducting conductor layer 3 In the range from the end face 12 of the substrate 1 of the second superconducting wire 10B to the end face 31 on the connecting end side of the superconducting conductor layer 3, the intermediate layers 2 and 2 are superposed on the intermediate layer 2D of the second connecting wire 10D. The thickness of the intermediate layer in the polymerization portion is thicker than that in other portions, so that the influence of metal diffusion can be more effectively reduced.

  In addition, since the superconducting wire connecting structure 100D is formed by the second removing step, the second arranging step, and the second forming step, the connecting structure 100D can be formed more easily. .

[Third embodiment]
FIG. 5 shows a superconducting wire connecting structure 100E according to the third embodiment. Regarding the connection structure 100E, the same components as those of the connection structure 100 described above are denoted by the same reference numerals and redundant description is omitted.

[Connection structure of superconducting wire]
The present embodiment shows a superconducting wire connecting structure 100E and a superconducting wire connecting method 100E and a superconducting wire connecting method.
As shown in FIG. 5, the superconducting wire connecting structure 100E according to the present embodiment is connected by a connecting method described later in a state where the connecting end portions of the first and second superconducting wires 10A and 10B are abutted to each other. It is formed. However, the superconducting wire connection structure 100E is not limited to the connection method described later, and may be formed by other connection methods.

  This connection structure 100E connects the base materials 1 and 1 of the first and second superconducting wires 10A and 10B, and the superconducting conductor layers 3 and 3 are connected via the first intermediate superconducting conductor layer 32E. .

In the first superconducting wire 10A, the superconducting conductor layer 3 at the connection end is removed with a predetermined length in the longitudinal direction L, and in the second superconducting wire 10B, the base 1 at the connecting end is in the longitudinal direction L. Is removed with a length shorter than the removal length of the superconducting conductor layer 3 of the first superconducting wire 10A.
And as for the 1st and 2nd superconducting wire 10A, 10B, the end surfaces 12 and 12 by the side of the connection edge part of the mutual base materials 1 and 1 are joined by welding, The intermediate | middle layer 2 of the 2nd superconducting wire 10B The connection end of the superconducting conductor layer 3 is placed on the upper surface of the connection end of the intermediate layer 2 of the first superconducting wire 10A.

  In the longitudinal direction L, the position of the end surface 21 of the intermediate layer 2 of the second superconducting wire 10B and the position of the end surface 31 on the connecting end side of the superconducting conductor layer 3 are the first and second superconducting wires 10A, 10B. Are extended to the first superconducting wire 10 </ b> A side from the positions of the end faces 12, 12 on the connecting end side of the base materials 1, 1. As a result, the intermediate layer 2 of the first superconducting wire 10A and the intermediate layer 2 of the second superconducting wire 10B are partially polymerized.

  Further, as described above, since the removal length of the superconducting conductor layer 3 of the first superconducting wire 10A is longer than the removal length of the base material 1 of the second superconducting wire 10B, the superconducting conductor of the first superconducting wire 10A. A gap is generated between the end surface 31 on the connection end portion side of the layer 3 and the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B. A first intermediate superconducting conductor layer 32E is formed in the gap by growing the superconducting material. The first intermediate superconducting conductor layer 32E is formed of the same or the same kind of superconducting material as the superconducting conductor layer 3.

With these structures, the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B and the first intermediate superconducting conductor layer 32E are arranged on the same plane parallel to the longitudinal direction L. Further, the base materials 1 and 1 of the superconducting wires 10A and 10B are also arranged on the same plane parallel to the longitudinal direction L. It is more preferable that the superconducting conductor layers 3 and 3 and the first intermediate superconducting conductor layer 32E are on the same straight line. Moreover, it is more preferable that the base materials 1 and 1 are on the same straight line.
Further, the end surfaces 31, 31 on the connection end side of the superconducting conductor layers 3, 3 of the superconducting wires 10A, 10B are joined to the end surfaces 321E, 321E of the first intermediate superconducting conductor layer 32E, and the end surfaces 31, 31, 321E are joined. , 321E are generally perpendicular to the longitudinal direction L.
As a result, a current can flow along the ab surface from the superconducting conductor layer 3 of the first superconducting wire 10A to the superconducting conductor layer 3 of the second superconducting wire 10B, and a good superconducting state can be formed.

Further, the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L and the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B are These do not coincide with the positions of the end surfaces 12 and 12 on the connection end side of the base materials 1 and 1, and are sufficiently separated from each other by 1 [μm].
Thereby, each base material 1, with respect to the end surfaces 31, 31 of the superconducting conductor layers 3, 3 of each superconducting wire 10A, 10B and the end surfaces 321E, 321E of both ends of the first intermediate superconducting conductor layer 32E. The influence of metal diffusion from the end faces 12 and 12 on the side of the connection end 1 is sufficiently reduced.

  Further, the first intermediate superconducting conductor layer 32E has the first and second superconducting wires 10A and 10B whose end surfaces 12 and 12 on the connection end portions side of the bases 1 and 1 are positioned in the first direction in the longitudinal direction L. Of the intermediate superconducting conductor layer 32E.

[Connection method of superconducting wire]
A method for connecting the superconducting wires forming the connection structure 100E will be described with reference to FIGS. 5 (A) to 5 (C).
First, as shown in FIG. 5A, the superconducting conductor layer 3 at the connection end of the first superconducting wire 10A is removed in a predetermined length in the longitudinal direction L and in the thickness direction. The surface is exposed (third removal step). Further, the base material 1 at the connection end of the second superconducting wire 10B is removed in the thickness direction in a length shorter than the removal length of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L, The surface (lower surface in the drawing) of the intermediate layer 2 is exposed (fourth removal step).
The removal in the third removal step and the fourth removal step is performed by mechanical polishing, chemical polishing (for example, etching treatment), or a combination thereof.
Note that either the third removal step or the fourth removal step may be performed first or simultaneously.

Further, as shown in FIG. 5 (B), the connection end of the intermediate layer 2 of the second superconducting wire 10B is superposed on the connection end of the intermediate layer 2 of the first superconducting wire 10A. The first superconducting wire 10A and the second superconducting wire 10B are arranged so that the base materials 1 and 1 are aligned on the same plane along the longitudinal direction L (third arranging step).
At this time, the end faces 12 and 12 on the connection end side of the bases 1 and 1 of the first and second superconducting wires 10A and 10B are joined together by welding. Thereby, the first superconducting wire 10A and the second superconducting wire 10B are connected with sufficient strength.

By the third arrangement step, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B are positioned on the same plane along the longitudinal direction L.
And as shown in FIG.5 (C), it is between the end surfaces 31 and 31 by the side of the connection edge part of each superconducting conductor layer 3 and 3 of 1st and 2nd superconducting wire 10A, 10B, and it is 1st superconducting. First intermediate superconducting conductor layer 32E is formed on the upper surface of intermediate layer 2 of wire 10A (third forming step).
It is desirable that the intermediate layer 2 of the first superconducting wire 10A has a sufficiently small surface roughness (for example, centerline average roughness Ra is 50 nm or less, more preferably 10 nm or less). .
In addition, the superconducting conductor layer 3 may partially remain in the thickness direction at the connection end of the second superconducting wire 10A. Even in this case, it is desirable that the surface roughness of the remaining superconducting conductor layer 3 is sufficiently small (for example, the center line average roughness Ra is 50 nm or less, more preferably 10 nm or less).

The formation of the first intermediate superconducting conductor layer 32E is performed by the MOD method. The details of the MOD method are the same as the formation of the first intermediate superconducting conductor layer 32 of the first embodiment.
The first intermediate superconducting conductor layer 32E is not limited to the MOD method, and any known method capable of forming a Y-based superconducting conductor layer, such as a CVD method or a PLD method, may be used.

Also, in the case of the first intermediate superconducting conductor layer 32E, after the formation, oxygen annealing treatment is performed in the same manner as in the case of the first intermediate superconducting conductor layer 32, and a stabilization layer forming step is added. May be.
Through these steps, the superconducting wire connection structure 100E is formed.

[Technical effects of the third embodiment]
In the superconducting wire connecting structure 100E, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B and the first intermediate superconducting conductor layer 32E are arranged along the same plane, and the first and second The base materials 1 and 1 of the superconducting wires 10A and 10B are arranged along the same plane.
Further, in the superconducting wire connecting structure 100E, the end surfaces 31, 31 on the connecting end side of the superconducting conductor layers 3, 3 of the superconducting wires 10A, 10B in the longitudinal direction L of the first and second superconducting wires 10A, 10B. (They coincide with the positions of the two end faces 321E of the first intermediate superconducting conductor layer 32E) and the positions of the end faces 12, 12 on the connecting end side of the substrates 1, 1 are 1 [μm] or more. It is distantly arranged.
Therefore, the superconducting wire connecting structure 100E also reduces the influence of metal diffusion on the superconducting conductor layers 3, 3, and 32E, as well as the superconducting wire connecting structure 100, and has sufficient superconducting characteristics and sufficient electric resistance. It is possible to reduce the power supply.
In addition, with the above connection structure 100E, the superconducting critical current density can be sufficiently increased between the first superconducting wire 10A and the second superconducting wire 10B, and the superconducting state can be satisfactorily maintained even at a large current. Is possible.

  Further, in the superconducting wire connecting structure 100E, the other superconducting conductor layer 32F is formed on the surface of the intermediate layer 2 of the first superconducting wire 10A, so that the base materials 1 and 1 are aligned with high accuracy in the thickness direction. Even without this, the film formation of the first intermediate superconducting conductor layer 32E is not affected. For this reason, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B can be satisfactorily connected to each other, and the burden of forming the connection structure 100E can be reduced.

Further, in the superconducting wire connecting structure 100E, the bases 1 and 1 of the superconducting wires 10A and 10B are joined, so that the connection strength of the connecting structure 100E can be improved.
In addition, since the first intermediate superconducting conductor layer 32E is formed between the end surfaces 31 and 31 on the connection end side of the superconducting conductor layers 3 and 3 of the respective superconducting wires 10A and 10B, for example, the base material and the base material Unlike the case where a film is formed inside a deep dent, such as between, the oxygen annealing after the film formation can be performed satisfactorily.
Further, the first intermediate superconducting conductor layer 32E has the first and second superconducting wires 10A and 10B whose end surfaces 12 and 12 on the connection end portions side of the bases 1 and 1 are positioned in the first direction in the longitudinal direction L. Of the intermediate superconducting conductor layer 32E. For this reason, the first intermediate superconducting conductor layer 32E can be satisfactorily formed on a smooth surface without a step, and the respective superconducting conductor layers 3 and 3 can be satisfactorily connected.

  Moreover, in the connection structure 100E of the superconducting wire, in the longitudinal direction L, the second superconducting wire 10B extends from the end surfaces 12, 12 on the connecting end side of the bases 1, 1 of the first and second superconducting wires 10A, 10B. Since the intermediate layers 2 and 2 are polymerized in the range up to the end surface 31 on the connection end side of the superconducting conductor layer 3, and the thickness of the intermediate layer is thicker than other portions in the superposed portion, the influence of metal diffusion is more effective. It becomes possible to reduce it.

  In addition, since the superconducting wire connecting structure 100E is formed by the third and fourth removing steps, the third arranging step, and the third forming step, the connecting structure 100E can be formed more easily. It becomes possible.

[Fourth embodiment]
FIG. 6 shows a superconducting wire connecting structure 100F according to the fourth embodiment. Regarding the connection structure 100F, the same components as those of the connection structure 100 described above are denoted by the same reference numerals and redundant description is omitted.

[Connection structure of superconducting wire]
This embodiment shows a superconducting wire connecting structure 100F, and a superconducting wire connecting method 100F and a superconducting wire connecting method.
As shown in FIG. 6, the superconducting wire connecting structure 100F according to the present embodiment is connected by a connecting method described later in a state where the connecting ends of the first and second superconducting wires 10A and 10B are polymerized. It is formed by. However, the superconducting wire connecting structure 100F is not limited to one formed by a connecting method described later, and may be formed by another connecting method.

  In this connection structure 100F, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B are connected to each other via another superconducting conductor layer 32F.

In the first superconducting wire 10A, the superconducting conductor layer 3 at the connection end is removed with a predetermined length in the longitudinal direction L, and in the second superconducting wire 10B, the base 1 at the connecting end is in the longitudinal direction L. Is removed with a length shorter than the removal length of the superconducting conductor layer 3 of the first superconducting wire 10A.
The removal length of the superconducting conductor layer 3 of the first superconducting wire 10A only needs to be long enough to place the tip of the second superconducting wire 10B on the removed portion.
Further, the removal length of the base material 1 of the second superconducting wire 10B is made shorter than the length of overlapping the connection end portion of the second superconducting wire 10B on the removed portion of the superconducting conductor layer 3 of the first superconducting wire 10A. In addition, it is desirable that the length of the end face 12 on the connection end portion side of the base material 1 is such that the influence of metal diffusion can be sufficiently reduced with respect to the other superconducting conductor layer 32F. For example, when Ni is used for the base material 1, it is desirable that the thickness be at least 1 [μm].

  Then, the second superconducting wire 10B has the first and second in a state in which the orientation of the superconducting conductor layer 3 with respect to the substrate 1 is reversed so that the arrangement in the thickness direction is opposite to that of the first superconducting wire 10A. The connection end of the second superconducting wire 10B is connected to the first superconducting wire 10A so that the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B are aligned along the same plane along the longitudinal direction L. However, it is disposed so as to be placed on the upper surface of the intermediate layer 2.

  Further, a gap is formed between the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A and the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B. The other superconducting conductor layer 32F is formed in the gap. The other superconducting conductor layer 32F is formed of the same or the same kind of superconducting material as the superconducting conductor layer 3.

With these structures, the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B and the other superconducting conductor layer 32F are arranged on the same plane parallel to the longitudinal direction L. It is more preferable that the superconducting conductor layers 3 and 3 and the other superconducting conductor layer 32F are on the same straight line.
Also, the end surfaces 31, 31 on the connection end side of the superconducting conductor layers 3, 3 of each superconducting wire 10A, 10B are joined to the end surfaces 321F, 321F of the other superconducting conductor layer 32F, and the end surfaces 31, 31, 321F, 321F are joined. Are generally perpendicular to the longitudinal direction L.
As a result, a current can flow along the ab surface from the superconducting conductor layer 3 of the first superconducting wire 10A to the superconducting conductor layer 3 of the second superconducting wire 10B, and a good superconducting state can be formed.

Further, the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L and the position of the end surface 31 on the connection end portion side of the superconducting conductor layer 3 of the second superconducting wire 10B are These do not coincide with the positions of the end surfaces 12 and 12 on the connection end side of the base materials 1 and 1, and are sufficiently separated from each other by 1 [μm].
Thereby, each base material 1 and 1 with respect to the end surfaces 31 and 31 of the connection end part side of the superconducting conductor layers 3 and 3 of each superconducting wire 10A and 10B, and the end surfaces 321F and 321F of the both ends of the other superconducting conductor layer 32F. The influence of metal diffusion from the end faces 12, 12 on the connecting end side is sufficiently reduced.

[Connection method of superconducting wire]
A method of connecting the superconducting wires forming the connection structure 100F will be described with reference to FIGS. 6 (A) to 6 (C).
First, as shown in FIG. 6A, the superconducting conductor layer 3 at the connection end of the first superconducting wire 10A is removed in a predetermined length in the longitudinal direction L and in the thickness direction. The surface is exposed (fifth removal step). Further, the base material 1 at the connection end of the second superconducting wire 10B is removed in the thickness direction in a length shorter than the removal length of the superconducting conductor layer 3 of the first superconducting wire 10A in the longitudinal direction L, The surface of the intermediate layer 2 is exposed (sixth removal step).
The removal in the fifth removal step and the sixth removal step is performed by mechanical polishing, chemical polishing (for example, etching treatment), or a combination thereof.
Note that either the fifth removal step or the sixth removal step may be performed first or simultaneously.

  Further, as shown in FIG. 6 (B), the second superconducting wire 10B is inverted over the thickness direction, and the second superconducting wire is formed on the connection end portion of the intermediate layer 2 of the first superconducting wire 10A. The superconducting conductor layer 3 at the connecting end of the wire 10B is polymerized, and the first superconducting wire 10A and the second superconducting wire are arranged so that the superconducting conductor layers 3 and 3 are aligned on the same plane along the longitudinal direction L. 10B is arranged (fourth arrangement step).

As shown in FIG. 6 (C), the first superconductivity is provided between the end surfaces 31 and 31 on the connection end portion side of the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B. Another superconducting conductor layer 32F is formed on the upper surface of the intermediate layer 2 of the wire 10A (fourth forming step).
It is desirable that the intermediate layer 2 of the first superconducting wire 10A has a sufficiently small surface roughness (for example, centerline average roughness Ra is 50 nm or less, more preferably 10 nm or less). .
In addition, the superconducting conductor layer 3 may partially remain in the thickness direction at the connection end of the second superconducting wire 10A. Even in this case, it is desirable that the surface roughness of the remaining superconducting conductor layer 3 is sufficiently small (for example, the center line average roughness Ra is 50 nm or less, more preferably 10 nm or less).

The formation of the other superconducting conductor layer 32F is performed by the MOD method. The details of the MOD method are the same as the formation of the first intermediate superconducting conductor layer 32 of the first embodiment.
Further, the other superconducting conductor layer 32F is not limited to the MOD method, and any known method capable of forming a Y-based superconducting conductor layer, such as a CVD method or a PLD method, may be used.

Also, in the case of the other superconducting conductor layer 32F, after the formation, oxygen annealing treatment is performed similarly to the case of the first intermediate superconducting conductor layer 32, and further, a stabilization layer forming step is added. good.
Through these steps, a superconducting wire connecting structure 100F is formed.

[Technical effects of the fourth embodiment]
In the superconducting wire connecting structure 100F, the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B and the other superconducting conductor layer 32F are arranged along the same plane.
Further, in the superconducting wire connecting structure 100F, the end surfaces 31 and 31 on the connecting end side of the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B in the longitudinal direction L of the first and second superconducting wires 10A and 10B. (They coincide with the positions of the two end faces 321F of the other superconducting conductor layer 32F) and the positions of the end faces 12 and 12 on the connecting end side of the substrates 1 and 1 are separated by 1 [μm] or more. It is arranged.
Therefore, the superconducting wire connecting structure 100F also reduces the influence of metal diffusion on each of the superconducting conductor layers 3, 3, and 32F in the same manner as the superconducting wire connecting structure 100, and has sufficient superconducting characteristics and sufficient electric resistance. It is possible to reduce the power supply.
In addition, the above connection structure 100F can sufficiently increase the superconducting critical current density between the first superconducting wire 10A and the second superconducting wire 10B, and maintain a superconducting state well even at a large current. Is possible.

  Further, in the superconducting wire connecting structure 100F, the other superconducting conductor layer 32F is formed on the surface of the intermediate layer 2 of the first superconducting wire 10A, so that the base materials 1 and 1 are aligned with high accuracy in the thickness direction. Even if not, it does not affect the film formation of the other superconducting conductor layer 32F. For this reason, it becomes possible to connect the superconducting conductor layers 3 and 3 of the first and second superconducting wires 10A and 10B satisfactorily, and to reduce the burden of forming the connection structure 100F.

  In addition, since the other superconducting conductor layer 32F is formed between the end faces 31, 31 on the connecting end side of the superconducting conductor layers 3 and 3 of the superconducting wires 10A and 10B, for example, between the base material and the base material Unlike the case where a film is formed inside a deep dent for the purpose, oxygen annealing after film formation can be performed satisfactorily.

  Further, since the superconducting wire connecting structure 100F is formed by the fifth and sixth removing steps, the fourth arranging step, and the fourth forming step, the connecting structure 100F can be formed more easily. It becomes possible.

1,1C, 1D Base material 2,2C, 2D Intermediate layer 3 Oxide superconducting conductor layer 3C Superconducting conductor layer (second intermediate superconducting conductor layer)
32, 32D, 32E First intermediate superconducting conductor layer 32F Other superconducting conductor layers 10, 10A, 10B Superconducting wire 10C First connecting wire 10D Second connecting wire 11 Film forming surfaces 12, 12D, 21, 31 , 31C, 321, 321D, 321E, 321F End face 100, 100D, 100E, 100F Connection structure

Claims (11)

A connection structure in which two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer are connected to each other at connection ends,
The superconducting conductor layers of the two superconducting wires are arranged along the same plane, and the base materials of the two superconducting wires are arranged along the same plane,
A first intermediate formed in any range between the end surface on the connection end portion side of the superconducting conductor layer of one of the superconducting wires and the end surface on the connection end portion side of the superconducting conductor layer of the other superconducting wire. With a superconducting conductor layer,
The positions of the end surfaces of the two superconducting wires on the connecting end side of the base material are both outside the range of the first intermediate superconducting conductor layer in the longitudinal direction of the two superconducting wires. Superconducting wire connection structure. The base material and the base material of the base material are in any range between the end surface on the connection end portion side of the superconducting conductor layer of one of the superconducting wires and the end surface on the connection end portion side of the superconducting conductor layer of the other superconducting wire. A second intermediate superconducting conductor layer comprising a superconducting conductor layer of the first connecting wire provided with a superconducting conductor layer formed on one side,
With respect to the longitudinal direction of the two superconducting wires, the positions of the end faces of the connection end portions of the superconducting conductor layers of the two superconducting wires and the first connecting wire are both based on the two superconducting wires. The superconducting wire connecting structure according to claim 1, wherein the connecting structure is different from the position of the end face on the connecting end side of the material. Between the base materials of the two superconducting wires, other base materials arranged along the same plane as these base materials are interposed,
2. The superconducting wire connection structure according to claim 1, wherein, in the longitudinal direction of the two superconducting wires, the positions of the end faces on both sides of the other base material are different from the positions of the end faces of the superconducting conductor layer.   With respect to the longitudinal direction of the two superconducting wires, the position of the end face of the intermediate layer of one of the superconducting wires is on the other superconducting wire side than the position of the end face on the connecting end side of the base material of the two superconducting wires The superconducting wire connecting structure according to claim 1, wherein   In the longitudinal direction of the two superconducting wires, there is a portion where the thickness of the intermediate layer is thicker than other portions within a predetermined range including the position of the end surface of the superconducting conductor layer of at least one of the superconducting wires. The superconducting wire connecting structure according to claim 4.   With respect to the longitudinal direction of the two superconducting wires, at least the position of the end surface of the connecting end portion of the superconducting conductor layer of the two superconducting wires and the position of the end surface of the connecting end portion of the base material of the two superconducting wires are at least The superconducting wire connecting structure according to any one of claims 1 to 5, wherein the connecting structure is separated by 1 [μm] or more.   A superconducting wire comprising the connection structure according to any one of claims 1 to 6. It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A first removal step of removing a part or all of the superconducting conductor layer at the connecting end of the two superconducting wires in the thickness direction;
A joining step for joining the connection ends of the base materials of the two superconducting wires; and
A first connecting wire provided with a base material and a superconducting conductor layer formed on one side of the base material in a portion where the superconducting conductor layer is removed, the superconducting conductor layer of the two superconducting wires and the A first disposing step of disposing the superconducting conductor layer of the first connecting wire so as to be positioned on the same plane;
The second superconducting conductor layer of the two superconducting wire rods is connected between the end surface of each of the connecting end portions and the end surfaces of the second intermediate superconducting conductor layer composed of the superconducting conductor layer of the first connecting wire rod. And a first forming step of newly forming one intermediate superconducting conductor layer. A method for connecting a superconducting wire. It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A second removal step of removing the base material at the connection end of the two superconducting wires;
An intermediate layer of a second connecting wire comprising a base material and an intermediate layer located on one side of the base material is in contact with the intermediate layer of the two superconducting wires exposed by the second removal step, and A second disposing step of disposing the second connecting wire so that the base material of the two superconducting wires and the base material of the second connecting wire are located on the same plane;
A first intermediate superconducting conductor layer is newly formed between an end surface of the superconducting conductor layer of one of the superconducting wires and an end surface of the other superconducting wire on the side of the connecting end of the superconducting conductor layer. A method for connecting a superconducting wire comprising a second forming step. It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A third removal step of removing part or all of the superconducting conductor layer at the connection end of the one superconducting wire in the thickness direction;
A fourth removal step of removing the base material of the connection end of the other superconducting wire;
A third disposing step of disposing the two superconducting wires so that the superconducting conductor layer or the exposed intermediate layer of the one superconducting wire remains and the exposed intermediate layer of the other superconducting wire are polymerized. When,
A third intermediate superconducting conductor layer is formed between the end face on the connection end side of the superconducting conductor layer of one of the superconducting wires and the end face on the connection end side of the superconducting conductor layer of the other superconducting wire. A method of connecting a superconducting wire, comprising the step of: It is a connection method of connecting two superconducting wires having a superconducting conductor layer formed on one side of a base material via an intermediate layer at each connection end,
A fifth removal step of removing part or all of the superconducting conductor layer at the connection end of one of the superconducting wires in the thickness direction;
A sixth removal step of removing the base material at the connection end of the other superconducting wire;
In one of the superconducting wires, the two superconducting wires are placed in a state where the superconducting conductor layer is partially or entirely removed, with the other superconducting wire facing the one superconducting wire. A fourth arrangement step for arranging the superconducting conductor layer of the wire to be located on the same plane;
And a fourth forming step of newly forming another superconducting conductor layer between the end faces of each of the two superconducting conductors on the side of the connecting end of the superconducting conductor layer. .

Images