JP2011134610A - Superconducting connection structure and connection method of superconducting wire rod and superconducting coil device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a superconducting connection structure with high connection strength, a connection method of a superconducting wire rod capable of being formed in a simple connection work, and a superconducting coil device. <P>SOLUTION: The superconducting connection structure 1A includes a base material 11, an oxide superconducting layer 17 fitted on the base material 11, and a stabilizing layer 19 fitted on the oxide superconducting layer 17, as well as at least two superconducting wire rods 2, 3 with one end part each to be a connecting end 21, 31, and a plurality of connection superconducting tapes 4 connecting the connecting ends 21, 31 themselves of the wire rods 2, 3. Each superconducting wire rod 2, 3 has a surface 21a, 31a of each stabilized layer 19 side so arranged to be on the same side, and that, to have side-end faces of the connecting ends 21, 31 adjacent to each other, and each connection superconducting tape 4 has its surface 4a at a stabilized layer 19 side jointed to over all surfaces 21a, 31a at each stabilized layer 19 side of each connecting end 21, 31 so as to be arrayed with intervals. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a superconducting connection structure in which at least two superconducting wires are connected to each other, a superconducting wire connecting method, and a superconducting coil device.

The RE-123 oxide superconductor discovered recently (REBa ₂ Cu ₃ O _{7-X, where} RE is a rare earth element including Y) is extremely promising in practice because it exhibits superconductivity above liquid nitrogen temperature. There is a strong demand for processing this into a wire and using it as a conductor for power supply. Then, as a method for processing the oxide superconductor into a wire, a metal having high strength, heat resistance, and easy to be processed into a wire is processed into a long tape shape on the metal base A method for forming an oxide superconductor into a thin film has been studied.

In addition, since the oxide superconductor has electrical anisotropy, it is necessary to control the crystal orientation when forming the oxide superconductor on the substrate. However, since the metal substrate itself is amorphous or polycrystalline, and its crystal structure is also significantly different from that of the oxide superconductor, an oxide superconductor film with good crystal orientation as described above is formed on the substrate. It is difficult to form.
Therefore, in order to solve the above problems, first, MgO, on which a physical characteristic value such as a coefficient of thermal expansion and a lattice constant is an intermediate value between the base material and the oxide superconductor on the metal base material, An intermediate layer made of a material such as YSZ (yttria stabilized zirconium) or SrTiO ₃ is formed, and an oxide superconducting thin film is formed on the intermediate layer.

As an example of the method for producing the intermediate layer, an ion beam assisted method (IBAD method) is known. This method uses constituent particles struck from a target by a sputtering method on a substrate. It is known as a method of depositing an intermediate layer while irradiating argon ions generated from an ion gun or the like simultaneously from an oblique direction (for example, 45 degrees). According to this IBAD method, an intermediate layer having high c-axis orientation and a-axis in-plane orientation can be obtained with respect to the film-forming surface on the substrate. Therefore, an oxide superconducting thin film is formed on this intermediate layer. An oxide superconducting conductor with excellent superconducting properties can be obtained by forming
In such an oxide superconductor, a stabilization layer made of a highly conductive metal material such as silver or copper is generally provided on the oxide superconducting layer. The stabilization layer functions as a bypass that commutates the current of the superconducting layer when the superconducting layer attempts to transition from the superconducting state to the normal conducting state.

By the way, in order to apply such an oxide superconducting conductor as a wire to a practical device, it is indispensable to establish a connection technology for the oxide superconducting wire, and studies on the connection technology are underway (for example, patent documents). 1-4).
First, in Patent Document 1, two oxide superconducting wires having an oxide superconducting layer and a stabilized silver layer provided in this order on a base tape are opposed to each other on the surface of the stabilized silver layer, A structure connected via solder has been proposed.
However, this connection structure has a problem that the front and back surfaces of the superconducting wires are reversed. When the stabilizing silver layers of the superconducting wires are facing the same side, the surfaces of the stabilizing silver layers are opposed to each other. Therefore, there is a problem that the end of one coil wire must be reversed.
Further, Patent Document 1 discloses a structure in which superconducting layers at the ends of superconducting wires are arranged flush with each other, and then a superconducting tape for connection is placed on and covered with a stabilized silver layer. However, it is not satisfactory in terms of connection strength. In addition, the oxide superconducting layer of the superconducting tape for connection is selected to have a lower melting point than the oxide superconducting layer to be connected, and the oxide superconducting layer having a low melting point is connected to each oxide superconducting layer on the connection target side. However, in order to satisfy the above-described melting point relationship, there is a problem that the constituent material of each oxide superconducting layer is limited.

Further, in Patent Documents 2 to 4, a connection superconducting layer is formed on each connection end of two oxide superconducting wires so as to contact each oxide superconducting layer across each connection end. A connection method in which the oxide superconducting layers are connected to each other has been proposed.
Here, since the connecting superconducting layer is formed by a vapor deposition technique, a large-scale film forming apparatus is required to perform this connecting method, and the connecting superconducting layer is formed. It takes time and the connection work takes a long time. Therefore, this connection method is not suitable for use at the work site and has a problem of lack of practicality.

JP 2000-133067 A JP 2001-319750 A JP 2005-63695 A JP 2008-66399 A

  The present invention has been made in view of the above-described conventional situation, and a superconducting connection structure capable of joining a plurality of superconducting wires with low connection resistance and high connection strength, and such a superconducting connection structure. It is an object of the present invention to provide a superconducting wire connecting method that can be formed by a simple connection operation without using a special device, and a superconducting coil device using such a superconducting connection structure.

The present invention has the following configuration in order to solve the above problems.
The superconducting connection structure of the present invention comprises a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer, and at least two of which end portions are connected ends. A plurality of superconducting wires, a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer, and connecting a plurality of connecting ends of the superconducting wires. A superconducting tape for connection, and the superconducting wires are arranged such that the surfaces of the conductive layers are on the same side, and the side end surfaces of the connection ends are adjacent to each other, Each of the superconducting tapes for connection has its surface on the conductive layer side bonded to both of the surfaces on the side of each of the conductive layers of the respective connection ends so as to be arranged at intervals. And

In the present invention, a metal plate is interposed between each connection end and each connection superconducting tape, and each metal plate has a surface on the conductive layer side of each connection end; A structure bonded to the surface of the connecting superconducting tape on the conductive layer side can be employed.
In the present invention, it is possible to employ a structure in which the metal plate is joined to both the surfaces of the connection ends on the side of the conductive layers side by side with the arrangement of the connection superconducting tapes.
In the present invention, the superconducting tapes for connection arranged in the length direction of the connection ends are covered, and at least both ends are bonded to the conductive layer surfaces of the connection ends over both the conductive layer side surfaces of the connection ends. It is possible to adopt a structure provided with a metal cover.

  The superconducting wire connecting method of the present invention includes a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer. A layer side surface is the same side, and the side end surfaces of the connection ends are adjacent to each other; a base material; a superconducting layer provided on the base material; and the superconducting layer. A plurality of superconducting tapes for connection comprising a conductive layer provided, the superconducting tapes for connection are arranged with a space between each other, and the surface on the conductive layer side is arranged for each of the connection ends. And a step of joining via solder over both surfaces of the conductive layer side.

The superconducting wire connecting method of the present invention includes a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer. The step of arranging the surface on the layer side to be the same side and the side end surfaces of each connection end being adjacent to each other, and arranging a plurality of metal plates at intervals, respectively, The step of joining via the first solder over both the conductive layer side surfaces, the base material, the superconducting layer provided on the base material, and the conductive layer provided on the superconducting layer Preparing a plurality of connecting superconducting tapes, and bonding the surface of each connecting superconducting tape on the conductive layer side to the surface of each of the metal plates via a second solder. And
In the present invention, the second solder preferably has a melting point lower than that of the first solder.

  The superconducting coil device of the present invention has at least two superconducting coils made of a wound body of superconducting wire wound with the surface on the conductive layer side facing outside, and each superconducting wire is connected to each connection end. A superconducting coil device constituting a superconducting connection structure, wherein the superconducting connection structure is the superconducting connection structure of the present invention.

  According to the superconducting connection structure of the present invention, at least two superconducting wires are arranged such that the surfaces of the respective conductive layers are on the same side, and the connection ends are adjacent to each other, and each connection superconductivity is provided. Since the tapes are arranged with a space between each other, and the respective conductive layer side surfaces are bonded to both the conductive layer side surfaces of each connection end, each connection end has a plurality of superconducting tapes for connection. Connected through. Thereby, a superconducting connection structure with low connection resistance and high connection strength can be obtained.

In addition, since this superconducting connection structure has a plurality of connecting superconducting tapes spaced apart from each other, when the temperature changes between room temperature and a low temperature in a cooled state, the connecting material and joining of the connecting superconducting tape The stress resulting from the difference in thermal expansion that occurs in the bonded portion with the material is dispersed, and the connection state of each connection superconducting tape to the surface of each connection layer on each conductive layer side is maintained.
Further, in this superconducting connection structure, the connected superconducting wires have the same front and back, so that good handling properties can be obtained as a superconducting connection structure.

In addition, this superconducting connection structure has a connecting portion formed by a connecting superconducting tape when a metal plate is interposed between the surface of each connecting end of each superconducting wire and each connecting superconducting tape. Reinforced by the metal plate, higher connection strength can be obtained.
When the metal plate is joined to both the conductive layer side surfaces of each connection end alongside the array of the plurality of connection superconducting tapes, each connection end is connected to each connection superconducting tape. In addition to being coupled with each other by a metal plate, higher connection strength can be obtained.
When a metal cover is provided so as to cover each connection superconducting tape over both conductive layer side surfaces of each connection end, each connection end is connected by each connection superconducting tape. Also, it is connected by a metal cover, and higher connection strength can be obtained.
Further, the superconducting tape for connection is covered with a metal cover, and at least both ends of the metal cover are joined to the surface side of the connection end. Since the metal cover material has a larger coefficient of thermal expansion, the metal cover presses the superconducting tape for each connection against the superconducting wire as a result of more shrinkage, so that the superconducting tape for each connection adheres to the surface of each connection end. Improves. Thereby, the contact resistance between each superconducting tape for connection and each superconducting wire can be lowered during actual use when the superconducting wire is energized after being cooled with a refrigerant.
Further, according to the method for connecting superconducting wires of the present invention, the superconducting connection structure as described above can be connected by a simple connecting operation without using a special apparatus such as a film forming apparatus. For this reason, even in the connection work site, each superconducting wire can be connected in a short time without any trouble in the work.

  Moreover, according to the superconducting coil device of the present invention, since the above-described superconducting connection structure is used, the connection resistance between the superconducting wires (coil wires) can be kept low, and good coil characteristics can be obtained. Further, even when the temperature changes between normal temperature and low temperature, the bonding state of each connection superconducting tape to the superconducting wire can be maintained, and low connection resistance and high connection strength can be maintained.

The schematic perspective view which shows 1st Embodiment of the superconducting connection structure of this invention. The schematic perspective view which shows the 1st superconducting wire and 2nd superconducting wire with which the superconducting connection structure shown in FIG. 1 is provided. The schematic perspective view which shows 2nd Embodiment of the superconducting connection structure of this invention. The schematic perspective view which shows 3rd Embodiment of the superconducting connection structure of this invention. The schematic perspective view which shows 4th Embodiment of the superconducting connection structure of this invention. The schematic perspective view which shows embodiment of the superconducting coil apparatus of this invention.

Hereinafter, a first embodiment of a superconducting connection structure according to the present invention will be described.
FIG. 1 is a schematic perspective view showing a first embodiment of the superconducting connection structure of the present invention, and FIG. 2 is a schematic view showing a first superconducting wire and a second superconducting wire provided in the superconducting connection structure shown in FIG. It is a perspective view. In FIG. 1 and FIGS. 3 to 5 to be described later, some layers of each superconducting wire are omitted for simplicity of explanation.

A superconducting connection structure 1A shown in FIG. 1 includes a plurality of superconducting wires (first superconducting wire 2 and second superconducting wire 3) and a plurality of superconducting wires 2 and 3 electrically and mechanically connected to each other. And a superconducting tape 4 for connection.
Each of the first superconducting wire 2 and the second superconducting wire 3 has a surface opposite to each substrate 11 (a surface of each stabilizing layer 19 described later) on the upper side, and each of the connection ends 21 and 31. One side end surfaces are arranged adjacent to each other, and a plurality of (three in the form of FIG. 1) connections are provided on the upper surfaces (surfaces of the stabilization layer 19) 21a and 31a of the connection ends 21 and 31, respectively. The superconducting tape 4 is adhered. In the following description, the upper surface 21a of the connection end 21 of the first superconducting wire 2 is referred to as “first connection region 21a”, and the upper surface 31a of the connection end 31 of the second superconducting wire is referred to as “second connection region 31a”. ".
As shown in FIG. 2, each of the superconducting wires 2 and 3 has a bed layer 12, an intermediate layer 15, a cap layer 16, and an oxide superconducting layer 17 laminated on a tape-like base material 11, respectively. A stabilization base layer 18 and a stabilization layer (conductive layer) 19 are laminated on the oxide superconducting layer 17, and the entire structure is covered with an insulating coating layer 20. In each superconducting wire 2 and 3, the bed layer 12 can be omitted. Further, the coating layer 20 is removed from the end portions of the first superconducting wire 2 and the second superconducting wire 3, and the portions of the connection ends 21 and 31 drawn from the coating layer 20 are joined as described later. .

The base material 11 applicable to each of the superconducting wires 2 and 3 of the present embodiment can be used as a base material of a normal superconducting wire, has only to be high strength, and is in the form of a tape to make a long cable. Preferably, those made of a heat resistant metal are preferred. For example, various metal materials such as silver, platinum, stainless steel, copper, nickel alloys such as Hastelloy, or ceramics arranged on these various metal materials can be used. Among various heat resistant metals, nickel alloys are preferable. Especially, if it is a commercial item, Hastelloy (trade name made by US Haynes Co., Ltd.) is suitable, and Hastelloy B, C, G, N, W, which have different component amounts such as molybdenum, chromium, iron, cobalt, etc. Any type can be used. What is necessary is just to adjust the thickness of the base material 11 suitably according to the objective, and it is 10-500 micrometers normally.
The bed layer 12 has high heat resistance and is intended to reduce interfacial reactivity, and is used to obtain the orientation of a film disposed thereon. Such a bed layer 12 is arranged as necessary, and is made of, for example, yttria (Y ₂ O ₃ ), silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), or the like. Composed. The bed layer is formed by a film forming method such as a sputtering method, and has a thickness of 10 to 200 nm, for example.

The intermediate layer 15 may have either a single layer structure or a multilayer structure, and is selected from materials that are biaxially oriented in order to control the crystal orientation of the oxide superconducting layer 17 laminated thereon. Specifically, preferred materials for the intermediate layer 15 are Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O 3, Gd ₂ O. ₃ , metal oxides such as Zr ₂ O ₃ , Ho ₂ O ₃ and Nd ₂ O ₃ can be exemplified.
If the intermediate layer 15 is formed with a good crystal orientation (for example, a crystal orientation of 15 ° or less) by the IBAD method, the crystal orientation of the cap layer 16 formed thereon has a good value (for example, the crystal orientation). Thus, the oxide superconducting layer 17 formed on the cap layer 16 can have a good crystal orientation and can exhibit excellent superconducting characteristics.

The thickness of the intermediate layer 15 may be adjusted as appropriate according to the purpose, but is usually in the range of 0.005 to 2 μm.
The intermediate layer 15 is formed by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, ion beam assisted vapor deposition (hereinafter abbreviated as IBAD), chemical vapor deposition (CVD). Method: Thermal coating decomposition method (MOD method); It can be laminated by a known method for forming an oxide thin film such as thermal spraying. In particular, the metal oxide layer formed by the IBAD method is preferable in that the crystal orientation is high and the effect of controlling the crystal orientation of the oxide superconducting layer 17 and the cap layer is high. The IBAD method is a method of orienting crystal axes by irradiating an ion beam at a predetermined angle with respect to an underlying vapor deposition surface during vapor deposition. Usually, an argon (Ar) ion beam is used as the ion beam. For example, the intermediate layer 15 made of Gd ₂ Zr ₂ O ₇ , MgO, or ZrO ₂ —Y ₂ O ₃ (YSZ) reduces the value of ΔΦ (FWHM: full width at half maximum), which is an index representing the degree of crystal orientation in the IBAD method. This is particularly preferable because it can be performed.

The cap layer 16 is formed through a process of epitaxial growth on the surface of the intermediate layer 15, and then grain growth (overgrowth) in the lateral direction (plane direction), and crystal grains are selectively grown in the in-plane direction. The ones made are preferred. Such a cap layer has a higher in-plane orientation degree than the intermediate layer 15 made of the metal oxide layer.
The material of the cap layer is not particularly limited as long as it can exhibit the above functions, but specifically, preferred examples include CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , and Zr ₂ O. ₃ , Ho ₂ O ₃ , Nd ₂ O _{3 and the} like. When the material of the cap layer is CeO ₂ , the cap layer may contain a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.

The CeO ₂ layer can be formed by a PLD method (pulse laser deposition method), a sputtering method, or the like, but it is desirable to use the PLD method from the viewpoint of obtaining a high film formation rate. The film formation conditions for the CeO2 layer by the PLD method can be performed in an oxygen gas atmosphere at a substrate temperature of about 500 to 1000 ° C. and about 0.6 to 100 Pa.
The film thickness of the CeO ₂ layer may be 50 nm or more, but is preferably 100 nm or more, and more preferably 500 nm or more in order to obtain sufficient orientation. However, if it is too thick, the crystal orientation deteriorates.

The oxide superconducting layer 17 may be a known one, and specifically, a material made of REBa ₂ Cu ₃ O _y (RE represents a rare earth element such as Y, La, Nd, Sm, Er, Gd) is exemplified. it can. Examples of the oxide superconducting layer 17 include Y123 (YBa ₂ Cu ₃ O _7-X ) or Gd123 (GdBa ₂ Cu ₃ O _7-X ).
The oxide superconducting layer 17 is laminated by a physical vapor deposition method such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, chemical vapor deposition (CVD), or thermal coating decomposition (MOD). In particular, from the viewpoint of productivity, it is preferable to use the TFA-MOD method (organic metal deposition method using trifluoroacetate, coating pyrolysis method), PLD method or CVD method.
This MOD method is a method in which a metal organic acid salt is applied and then thermally decomposed. After a solution in which a metal component organic compound is uniformly dissolved is applied onto a substrate, the substrate is heated and thermally decomposed. This is a method of forming a thin film on top, and is suitable for the production of a long tape-shaped oxide superconducting conductor because it does not require a vacuum process and enables high-speed film formation at low cost.

  Here, as described above, when the oxide superconducting layer 17 is formed on the cap layer 16 having a good orientation, the oxide superconducting layer 17 laminated on the cap layer 16 also matches the orientation of the cap layer 16. Crystallize as follows. Therefore, the oxide superconducting layer 17 formed on the cap layer 16 has almost no disorder in the crystal orientation, and in each of the crystal grains constituting the oxide superconducting layer 17, The c-axis that hardly allows electricity to flow in the thickness direction is oriented, and the a-axis or the b-axis is oriented in the length direction of the metal substrate 11. Therefore, the obtained oxide superconducting layer 16 is excellent in quantum connectivity at the crystal grain boundary, and hardly deteriorates in the superconducting characteristics at the crystal grain boundary, so that it is easy to flow electricity in the length direction of the metal base 2. A sufficiently high critical current density is obtained.

The stabilizing base layer 18 laminated on the oxide superconducting layer 17 is formed as a layer made of a metal material having good conductivity, such as Ag, and a low contact resistance with the oxide superconducting layer 17.
The stabilizing layer 2 is made of a highly conductive metal material, and when the oxide superconducting layer 17 transitions from the superconducting state to the normal conducting state, the current of the oxide superconducting layer 17 commutates together with the stabilizing base layer 18. Acts as a bypass.
The metal material constituting the stabilization layer 2 is not particularly limited as long as it has good conductivity, but it is preferable to use a relatively inexpensive material such as Cu. This makes it possible to increase the thickness of the stabilization layer 2 while keeping the material cost low, and the superconducting wires 2 and 3 that can withstand accidental currents can be obtained at low cost.

As shown in FIG. 1, in the 1st superconducting wire 2 and the 2nd superconducting wire 3 which were comprised as mentioned above, the surface (1st connection area | region) of each stabilization layer 19 of each connection end 21 and 31 is shown. A plurality of (three in the present embodiment) connecting superconducting tapes 4 are joined to 21a and the second connecting region 31a). Each connection superconducting tape 4 electrically and mechanically connects the respective superconducting wires 2 and 3, and has approximately the same length as the total width W of the first connection region 21 and the second connection region 31. It has a strip shape.
As each superconducting tape 4 for connection, the same thing as each superconducting wire 2 and 3 can be used. Here, each superconducting wire 2, 3 and each connecting superconducting wire 4 may have the same layer configuration (the same kind of layers and constituent materials are provided) or different layer configurations, It is easier to use the same layer structure because a part of each superconducting wire 2 and 3 can be cut and used as the connecting superconducting tape 4. In the present embodiment, the case where the same superconducting wire 2 and 3 as each superconducting wire 4 is used as an example is used as each superconducting tape 4 for connection.

Each superconducting tape 4 for connection has a surface 4a of the stabilization layer 19 facing each connection region 21a, 31a of each superconducting wire 2, 3, and the length direction of each connection region 21a, 31a. as the width direction substantially perpendicular to, the connection region 21a, are disposed across the boundary of and what 31a, are arranged in parallel with an interval W ₂ to each other. And the surface 4a of each stabilization layer 19 of each connection superconducting tape 4 is joined to each connection region 21a, 31a of each superconducting wire 2, 3 via solder.
As a result, the first superconducting wire 2 and the second superconducting wire 3 are connected electrically and mechanically by connecting the connection ends 21 and 31 to each other by the connecting superconducting tape 4. By connecting the superconducting wires 2 and 3 via the connecting superconducting tape 4 in this way, the connection resistance can be kept low and the superconducting wires 2 and 3 can be firmly connected.

The superconductive connection structure 1A of this embodiment, a plurality of connecting the superconducting tape 4, is characterized in that provided at a distance W ₂ from each other. Thereby, even if the temperature of the superconducting connection structure 1A changes between normal temperature and low temperature, the bonding state of each connection superconducting tape 4 to each connection region 21a, 31a is maintained, and low connection resistance and high connection strength are maintained. can do.
That is, the superconducting connection structure 1A may be subjected to a temperature change (normal temperature / low temperature cycle) from normal temperature to low temperature and from low temperature to normal temperature. Along with this temperature change, each part constituting the superconducting connection structure 1A may be loaded depending on the coefficient of thermal expansion.

Here, unlike the present invention, when a wide superconducting tape for connection is used, when the temperature of the superconducting connection structure 1A changes from room temperature to low temperature and from low temperature to room temperature, it is relatively large in the solder and the bonding portion with the solder. Stress is generated. As a result, a part of the solder joining the wide connecting superconducting tape may be peeled off and the adhesion may be impaired.
On the other hand, when a plurality of narrow connection superconducting tapes 4 are used and spaced apart from each other, even if the temperature of the superconducting connection structure 1A changes between normal temperature and low temperature, Since the stress generated in the bonding material and the bonding portion with the bonding material can be dispersed, it is easy to maintain the bonding state of each connection superconducting tape 4 to each connection region 21a, 31a.
Moreover, in this superconducting connection structure 1A, since the front and back of the connected superconducting wires 2 and 3 coincide, good handleability can be obtained.

Next, a first embodiment of the superconducting wire connecting method according to the present invention will be described by taking as an example the case of forming the superconducting connection structure 1A shown in FIG.
First, two superconducting wires (first superconducting wire 2 and second superconducting wire 3) to be connected and a plurality (three in this embodiment) of connecting superconducting tapes 4 are prepared.
Next, each connection superconducting tape 4 is bonded to the connection region of each connection superconducting tape in each connection region 21a, 31a via solder.
The solder is not particularly limited. For example, in addition to Pb—Sn alloy solder, lead-free solder such as Sn—Ag alloy, Sn—Bi alloy, Sn—Cu alloy, Sn—Zn alloy, etc. Of these, one or a combination of two or more can be used. Of these, solder having a melting point of 300 ° C. or lower is preferably used. As a result, soldering can be performed at a temperature of 300 ° C. or lower, so that it is possible to prevent the oxide superconducting layer 17 from being desorbed by heat of soldering and deteriorating its characteristics.

  As described above, in the superconducting wire connecting method of the present embodiment, the two superconducting wires 2 and 3 can be connected by a simple soldering operation without using a special device. For this reason, according to this superconducting wire connecting method, the superconducting wires 2 and 3 can be connected without difficulty in a short time without selecting a place. In addition, about solder, the method of carrying out the thermocompression bonding of what was previously formed in the surface of the stabilization layer 19 of the superconducting tape 4 for a connection by the plating method is employable.

Next, each 2nd Embodiment of the connection method of the superconducting connection structure of this invention and a superconducting wire is described.
FIG. 3 is a schematic perspective view showing a second embodiment of the superconducting connection structure of the present invention.
Hereinafter, the superconducting connection structure and the superconducting wire connecting method according to the second embodiment will be described. However, differences from the first embodiment will be mainly described, and description of similar matters will be omitted.
The superconducting connection structure 1B according to the present embodiment is configured except that the metal plate 5 is interposed between the connection regions 21a and 31a of the superconducting wires 2 and 3 and the superconducting tape 4 for connection. The superconducting connection structure 1A of the first embodiment has the same configuration.

Each metal plate 5 has the same planar shape as each connection superconducting tape 4 provided thereabove, and is joined to each connection region 21a, 31a via a first solder.
In addition, each superconducting tape 4 for connection has a surface 4a on the stabilization layer 19 side opposed to the surface on the opposite side of each connection region 21a, 31a side of each metal plate 5, and more than the first solder. It is joined via a second solder having a low melting point.

In the second embodiment, the same effect as in the first embodiment can be obtained.
Further, in the superconducting connection structure 1B of the second embodiment, each metal plate 5 is interposed between each connection region 21a, 31a and each connection superconducting tape 4, in particular. The superconducting tape 4 is reinforced by the respective metal plates 5, and higher connection strength can be obtained.
As a constituent material of each metal plate 5, it is preferable that it is excellent in mechanical strength and has good conductivity. As a constituent material of each metal plate 5, silver or copper is suitable.

Next, a second embodiment of the superconducting wire connecting method of the present invention will be described by taking as an example the case of forming the superconducting connection structure 1B shown in FIG.
First, two superconducting wires (first superconducting wire 2 and second superconducting wire 3) to be connected, a plurality (three in this embodiment) of connecting superconducting tapes 4, and each connecting superconducting device The same number of metal plates 5 as the tape 4 are prepared.
And after installing each superconducting wire 2 and 3 so that the surface (each connection area | region 21a, 31a) by the side of the stabilization layer 19 becomes upper and the side end surface of each connection edge part 21 and 31 adjoins, each superconductivity Each metal plate 5 is soldered to each metal plate joining region of each connection region 21a, 31a of the wires 2 and 3 via the first solder.
Next, each connection superconducting tape 4 is soldered on each metal plate 5 via a second solder having a melting point lower than that of the first solder.
Here, by using a second solder having a melting point lower than that of the first solder as the solder for bonding each connection superconducting tape 4, each connection superconducting tape at a lower temperature than the bonding process of each metal plate 5. 4 can be soldered. Thereby, it can suppress that the 1st solder fuse | melts at this process and the metal plate 5 shifts | deviates, and each metal plate 4 and each superconducting tape 4 for connection can be adhere | attached with a sufficient positional accuracy.
Through the above steps, the superconducting connection structure 1B shown in FIG. 3 can be formed.

Next, each 3rd Embodiment of the connection method of the superconducting connection structure of this invention and a superconducting wire is described.
FIG. 4 is a schematic perspective view showing a third embodiment of the superconducting connection structure of the present invention.
Hereinafter, although the superconducting connection structure and the superconducting wire connecting method according to the third embodiment will be described, differences from the first embodiment will be mainly described, and description of similar matters will be omitted.

The superconducting connection structure 1C according to the present embodiment has a configuration in which the metal plate 6 is disposed in each connection region 21a, 31a of each superconducting wire 2 and 3 along with the arrangement of the superconducting tape 4 for connection. The configuration is the same as that of the superconducting connection structure 1A of the first embodiment.
The metal plate 6 has a strip shape having a length substantially the same as the total width W of the first connection region 21 a and the second connection region 31 a of each superconducting wire 2, 3.
The metal plate 6 is arranged across the boundary between the connection regions 21a and 31a so that the length direction thereof is substantially orthogonal to the width direction of the connection regions 21a and 31a. In front of 4, the connecting superconducting tape 4 is spaced apart. And this metal plate 6 is joined to each connection area | region 21a, 31a via solder.

In the third embodiment, the same effect as in the first embodiment can be obtained.
Further, in the superconducting connection structure 1C of the third embodiment, in particular, the metal plates 6 are arranged in the connection regions 21a and 31a of the superconducting wires 2 and 3 along with the arrangement of the superconducting tapes 4 for connection. Accordingly, the connection ends 21 and 31 of the superconducting wires 2 and 3 are connected by the connecting superconducting tape 4 and also by the metal plate 6. Therefore, higher connection strength can be obtained.
Further, in the configuration in which the connection superconducting tape 4 and the metal plate 6 are arranged on the surfaces of the connection ends 21 and 31, the connection ends 21 and 31 are compared with the configuration in which the connection superconducting tape 4 is stacked on the metal plate. The effect that the thickness of 31 can be made thin is also acquired.

Next, each 4th Embodiment of the connection method of the superconducting connection structure of this invention and a superconducting wire is described.
FIG. 5 is a schematic perspective view showing a fourth embodiment of the superconducting connection structure of the present invention.
Hereinafter, the superconducting connection structure and the superconducting wire connecting method according to the fourth embodiment will be described. However, differences from the first embodiment will be mainly described, and description of similar matters will be omitted.

The superconducting connection structure 1D according to this embodiment is provided with a metal cover 7 so as to cover each connection superconducting tape 4 over both connection regions 21a and 31a of each superconducting wire 2 and 3. Is configured similarly to the superconducting connection structure 1A of the first embodiment.
The metal cover 7 has a belt-like shape in which the central region is bent, and has a width substantially the same as the total width W of the first connection region 2 and the second connection region 3 of each superconducting wire 2, 3, and superconducting for connection. The length is longer than the arrangement length of the tapes 4.
The metal cover 7 covers the connection superconducting tape 4 so that the concave surface faces the connection regions 21a and 31a and the longitudinal direction thereof substantially coincides with the longitudinal direction of the superconducting wires 2 and 3. Arranged on the connection regions 21a and 31a and the superconducting tapes 4 for connection via solder.

Also in the fourth embodiment, the same effect as in the first embodiment can be obtained.
In the superconducting connection structure 1D of the fourth embodiment, in particular, each connection region 21a, 31a is provided with a metal cover 7 so as to cover each connection superconducting tape 4, thereby each superconducting wire 2, 3 are connected by the superconducting tape 4 for connection and also by the metal cover 7. Each connection superconducting tape 4 is reinforced by a metal cover 7. Therefore, higher connection strength can be obtained.

  As a constituent material of the metal cover, it is preferable that it is excellent in mechanical strength and has good conductivity. Since the metal plate 7 has good conductivity, when the superconducting layer of the superconducting wires 2 and 3 tries to transition from the superconducting state to the normal conducting state, the metal cover 7 commutates the current of the superconducting wires 2 and 3. To act as a bypass. As a result, it is possible to prevent heat generation at the joint portions of the superconducting wires 2 and 3 and the portions of the superconducting tapes 4 for connection. From such a point, as the constituent material of the metal plate cover 7, highly conductive silver or copper is suitable.

  Further, the metal cover 7 is made of a highly conductive metal material such as copper or silver, ceramics constituting the oxide superconducting layer 17 of each superconducting wire 2, 3, heat-resistant alloy such as Hastelloy constituting the substrate 11, or rare earth. Since the thermal expansion coefficient is larger than that of the oxide superconducting material, the superconducting connection structure 1D tends to shrink more than the superconducting wires 2 and 3 when cooled by the refrigerant. As a result, the metal cover 7 is reduced while being pulled from both sides in the longitudinal direction, and the pressing force is applied to each connection superconducting tape 4 so as to press them against the connection regions 21a and 31a. Works. Thereby, the adhesiveness of each superconducting tape 4 for connection and each connection area | region 21a, 31a can be made high.

In order to form the superconducting connection structure 1D shown in FIG. 5, after the structure shown in FIG. 1 is fabricated, the connection superconducting tape 4 is covered with the connection regions 21a and 31a of the superconducting wires 2 and 3, respectively. The metal cover 7 may be soldered to the surfaces of the connection ends 21 and 31 through solder.
Here, since the connecting superconducting tapes 4 are provided with a space therebetween, solder can be filled between the connecting superconducting tapes 4. As a result, the metal cover 7 can be uniformly and more firmly bonded to each connection superconducting tape 4.
Through the above steps, the superconducting connection structure 1D shown in FIG. 5 can be formed.
As described above, in the superconducting wire connecting method of the present embodiment, the two superconducting wires 2 and 3 can be connected by a simple connecting operation without using a special device. For this reason, according to this superconducting wire connecting method, it is possible to connect the superconducting wires 2 and 3 without difficulty in a short time without selecting a work place.

Next, an embodiment of a superconducting coil device according to the present invention will be described.
FIG. 6 shows one embodiment of the superconducting coil device of the present invention. FIG. 6 (a) is a schematic perspective view, and FIG. 6 (b) is a side view.
The superconducting coil device 100 includes a first superconducting coil 101 composed of a first superconducting wire 2, a second superconducting coil 102 composed of a second superconducting wire 3, and each superconducting wire 2,3. A plurality of (three in the present embodiment) connecting superconducting tapes 4 are connected.
As each superconducting wire 2, 3 and each superconducting tape 4 for connection, the same ones as in the first embodiment can be used.
The first superconducting coil 101 is configured by winding the first superconducting wire 2 many times counterclockwise with the surface of the stabilization layer 19 facing outside.
Further, the second superconducting coil 102 is stacked above the first superconducting coil 101, and the second superconducting wire 3 is wound many times clockwise with the surface of the stabilization layer 19 facing outside. Has been.
And each edge part (connection end 21 and 31) of the outer side of the 1st superconducting wire 2 and the 2nd superconducting wire 3 is distribute | arranged so that the side end surfaces may adjoin each other, A plurality of connecting superconducting tapes 4 are bonded to the outer surface.
In the following description, the outer surface of the connection end 21 of the first superconducting wire 2 is referred to as “first connection region 21a”, and the outer surface of the connection end 31 of the second superconducting wire 3 is referred to as “second connection region”. 31a ".

Each of the superconducting tapes 4 for connection has a surface 4a of the stabilization layer 19 facing the connection regions 21a and 31a of the superconducting wires 2 and 3, respectively, and its length direction is the width of each connection region 21a and 31a. as a direction substantially orthogonal, each connection region 21a, are disposed across the boundary of and what 31a, are arranged in parallel at an interval W ₂ to each other. And the surface of each stabilization layer 19 of each superconducting tape 4 for connection is joined to each connection area | region 21a, 31a of each superconducting wire 2 and 3 via solder. That is, each connecting the superconducting tape 4, so as to be arranged at a distance W ₂ from each other, respectively, the surface 4a of the stabilizing layer 19 is joined each connection area 21a, over both 31a.
As a result, the first superconducting wire 2 (first superconducting coil 101) and the second superconducting wire 3 (second superconducting coil 102) are connected to each other at the connection ends 21 and 31 by the connection superconducting tape 4. Connected, electrically and mechanically connected. Thus, by connecting the superconducting wires 2 and 3 via the connecting superconducting tapes 4, the connection resistance can be kept low, and good coil characteristics can be obtained. Further, the superconducting wires 2 and 3 are firmly connected to each other, and an excellent connection strength can be obtained.

  The superconducting connection structure, the superconducting wire connecting method, and the superconducting coil device of the present invention have been described above. In each embodiment, each part of the superconducting connecting structure, each step of the superconducting wire connecting method, and the superconducting coil device are configured. Each part to be performed is an example, and can be appropriately changed without departing from the scope of the present invention. For example, although the superconducting connection device of the first embodiment is used in the superconducting coil device of the fourth embodiment, the superconducting connection device of the second embodiment to the third embodiment is used as the superconducting coil device of the present invention. May be used.

  The present invention can be used for a superconducting connection structure used in various power devices such as a superconducting motor and a current limiting device.

  DESCRIPTION OF SYMBOLS 1A, 1B, 1C, 1D ... Superconducting connection structure, 2 ... 1st superconducting wire, 21 ... Connection end, 21a ... 1st connection area, 3 ... 2nd superconducting wire, 31 ... Connection end, 31a ... 1st 2 connection regions, 4 ... superconducting tape for connection, 5, 6 ... metal plate, 7 ... metal cover, 11 ... base material, 12 ... bed layer, 15 ... intermediate layer, 16 ... cap layer, 17 ... oxide superconducting layer , 18 ... Stabilization base layer, 19 ... Stabilization layer, 100 ... Superconducting coil device, 101 ... First superconducting coil, 102 ... Second superconducting coil.

Claims (8)

A substrate, a superconducting layer provided on the substrate, and a conductive layer provided on the superconducting layer, and at least two superconducting wires whose ends are connected ends;
A substrate, a superconducting layer provided on the substrate, and a conductive layer provided on the superconducting layer, and a plurality of superconducting tapes for connecting the connection ends of the superconducting wires. Have
The superconducting wires are arranged such that the surfaces on the conductive layer side are the same side, and the side end surfaces of the connection ends are adjacent to each other.
Each of the superconducting tapes for connection is bonded to both the surfaces of the respective conductive layers at the respective connection ends so as to be arranged at intervals. A superconducting connection structure. A metal plate is interposed between each connection end and each connection superconducting tape,
2. The superconducting connection structure according to claim 1, wherein each of the metal plates is bonded to a surface of the connection end on the conductive layer side and a surface of the connection superconducting tape on the conductive layer side. body.   The superconductivity according to claim 1 or 2, wherein a metal plate is joined to both the surfaces of the respective connection ends on the side of each conductive layer side by side with the array of the superconducting tapes for connection. Connection structure.   A metal cover that covers each of the connection superconducting tapes arranged in the length direction of the connection end and has at least both ends bonded to the conductive layer surface of each connection end across both surfaces of the connection layer on the conductive layer side. The superconducting connection structure according to claim 1, wherein the superconducting connection structure is provided. At least two superconducting wires comprising a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer, the surfaces of the respective conductive layers are on the same side, and , A step of arranging the side end surfaces of each connection end to be adjacent to each other;
A plurality of superconducting tapes for connection comprising a substrate, a superconducting layer provided on the substrate, and a conductive layer provided on the superconducting layer are prepared, and the connecting superconducting tapes are spaced apart from each other. Connecting the superconducting wires, characterized in that they have a step of joining them via soldering over the respective conductive layer side surfaces of the respective connection ends. Method. At least two superconducting wires comprising a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer, the surfaces of the respective conductive layers are on the same side, and , A step of arranging the side end surfaces of each connection end to be adjacent to each other;
A plurality of metal plates are arranged with a space between each other, and the surface on the conductive layer side is bonded to both the conductive layer side surfaces of the connection ends via the first solder. Process,
A plurality of superconducting tapes for connection comprising a base material, a superconducting layer provided on the base material, and a conductive layer provided on the superconducting layer are prepared, and the surface on the conductive layer side of each superconducting tape for connection A method of joining the surface of each metal plate to the surface of the metal plate via a second solder.   The superconducting wire connecting method according to claim 6, wherein the second solder has a melting point lower than that of the first solder. It has at least two superconducting coils composed of a wound body of superconducting wire wound with the surface on the conductive layer side outside, and each superconducting wire is connected to each connection end to constitute a superconducting connection structure. A superconducting coil device comprising:
The superconducting connection device according to any one of claims 1 to 4, wherein the superconducting connection structure is a superconducting coil device.

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