JP2014130793A - Connection structure of oxide superconductive wire material and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a connection structure of an oxide superconductive wire material and its manufacturing method.SOLUTION: There is provided a connection structure of an oxide superconductive wire material 30 which a pair of oxide superconductive wire materials 2 and 3 obtained by laminating an intermediate layer 11, an oxide superconductive wire layer 12 and a stabilization layer 14 on a tape-like base material 10 is joined each other, the stabilization layers 14 and 14 near each ends 2a and 3a of a pair of the oxide superconductive wire material 2 and 3 are arranged to form an overlapping part 50 by facing each other, a connection area 51 connected by a conductive joint material 22 at least a part of the overlapping part 50 is formed, and non-connection area 52 not connected by a conductive connection material having a length in the longer direction of 1 mm to 100 mm at least at a part of end in the longer direction in the overlapping part 50.

Description

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

In recent years, Bi-based superconducting wire Bi ₂ Sr ₂ CaCu ₂ O _{8 + δ} (Bi2212), Bi ₂ Sr ₂ Ca ₂ Cu ₃ O _{10 + δ} (Bi2223) and RE-123-based superconducting wire REBa ₂ Cu ₃ O _7-x (RE123: RE is Development of oxide superconducting wires such as rare earth elements including Y and Gd is underway. These oxide superconducting wires have a critical temperature of about 90-100K and exhibit superconductivity above the liquid nitrogen temperature. Therefore, these oxide superconducting wires are considered to be extremely promising materials for practical use. There is a demand for use as a conductor or a superconducting coil.

  The Bi-based superconducting wire has a structure manufactured by the Powder In Tube method (PIT method) or the like so that the Bi-based superconducting layer is covered with an Ag sheath material. On the other hand, in the RE-123 series superconducting wire, an oxide superconducting layer is laminated on a tape-shaped metal substrate by a film forming method through an intermediate layer, and the first stabilization of thin silver is further performed on the oxide superconducting layer. A structure in which a layer is formed and a second stabilization layer made of a highly conductive metal material such as copper is provided thereon is employed.

  In order to apply the RE-123 series oxide superconducting wire to a practical device, a technique for connecting the oxide superconducting wire is desired. For example, in Patent Document 1, as shown in FIG. 25, end portions of a pair of oxide superconducting wires 211 and 212 in which an intermediate layer 203, an oxide superconducting layer 204, and a stabilizing layer 205 are laminated on a base material 202. A connection structure 200 is disclosed in which the overlapping portions 220 are formed by overlapping the vicinity, the overlapping portions 220 are joined by solder (not shown), and further reinforced by a connection plate 206.

JP 2007-266149 A

However, in the connection structure 200 described in Patent Document 1, it is possible to improve the mechanical strength of the connection portion by reinforcing the connection portion with the connection plate 206, but the connection structure 200 is bent to the connection structure 200. When this is added, the oxide superconducting layer 204 may be deteriorated.
In the connection structure 200 described in Patent Document 1, the entire surface of the overlapping portion 220 of the pair of oxide superconducting wires 211 and 212 is joined by soldering. When joining the entire surface of the overlapping portion 220, it is necessary to pressurize the overlapping portion 220 of the pair of oxide superconducting wires 211 and 212, and excess solder causes the superposition of the oxide superconducting wires 211 and 212 due to the pressing. It protrudes from the part 220 and solidifies by adhering to each end face. As a result, the thickness of the solder locally increases on both outer sides of the overlapping portion 220, and when the connection structure 200 is bent, a load is concentrated in the vicinity of both sides in the longitudinal direction of the overlapping portion 220 and the oxide superconducting layer 204. There was a possibility that the crystal structure of this was damaged, and the structure was weak against bending.

  This invention is made | formed in view of the above situations, and it aims at providing the connection method of the connection structure of an oxide superconducting wire strong to a bending, and an oxide superconducting wire.

In order to solve the above problems, the oxide superconducting wire connecting structure of the present invention is a tape-like base material in which a pair of oxide superconducting wires are formed by laminating an intermediate layer, an oxide superconducting layer, and a stabilizing layer. The stabilization structure is arranged such that the stabilizing layers in the vicinity of the ends of the pair of oxide superconducting wires are opposed to each other to form an overlapping portion, and at least a part of the overlapping portion And a joining region joined by a conductive joining material is formed, and at least one of the longitudinal end portions in the overlapping portion is not joined by a conductive joining material having a longitudinal length of 1 mm or more and 100 mm or less. A non-joining region is formed.
The non-bonding region at the inner end of the overlapping portion suppresses the conductive bonding material from protruding from the overlapping portion. Therefore, it does not solidify on both outer sides of the overlapped portion, and since the joint portion made of the conductive joint material is not locally thickened in the connection structure, a portion that is not easily bent is not generated.
Note that if the length of the non-bonded region is less than 1 mm, it is difficult to insert the masking material, and the non-bonded region may not be reliably ensured. Moreover, when it exceeds 100 mm, a connection part becomes long and the handling of a connection structure worsens and is unpreferable.
In the present invention, a structure is adopted in which the length of one non-bonded region is longer than the length of the other non-bonded region in the length of the paired non-bonded region located on both sides of the overlapping portion. Also good.
When a bending along the stacking direction is applied to the connection structure, a load may be greatly applied to the end portion side of the oxide superconducting wire located outside. In this case, by increasing the longitudinal length of the non-bonded region on the end side of the outer oxide superconducting wire, the load on the outer connection structure can be more effectively reduced.

The connection structure of the oxide superconducting wire of the present invention includes the first oxide superconducting wire, the second oxide superconducting wire, and the third oxide superconducting wire which are the three oxide superconducting wires, The first and second oxide superconducting wires are arranged adjacent to each other with a predetermined gap between the ends to be connected, with the side on which the oxide superconducting layer is formed aligned with the base material, The stabilization layer of the third oxide superconducting wire is bridged to the stabilization layer of the first and second oxide superconducting wires so as to straddle the adjacent ends, and the first and second overlapping layers are bridged. A bonding region bonded to at least a part of the first overlapping portion by a conductive bonding material, and at least one of longitudinal end portions in the first overlapping portion. The length in the longitudinal direction is 1 mm or more and 100 mm or less A non-bonded region that is not bonded by the conductive bonding material is formed, a bonding region bonded by the conductive bonding material is formed in at least a part of the second overlapping portion, and the second overlapping region is formed. A non-joining region that is not joined by a conductive joining material having a length in the longitudinal direction of 1 mm or more and 100 mm or less is formed on at least one of the end portions in the longitudinal direction in the mating portion.
According to the present invention, since the pair of oxide superconducting wires to be connected is arranged with the stacking direction aligned, there is no reverse inversion of the oxide superconducting wire at the connecting portion. Moreover, the non-joining region at the inner end of the overlapping portion suppresses the conductive bonding material from protruding from the overlapping portion. Therefore, it does not solidify on both outer sides of the overlapped portion, and since the joint portion made of the conductive joint material is not locally thickened in the connection structure, a portion that is not easily bent is not generated. Furthermore, by arranging the end portions of the first and second oxide superconducting wires apart from each other, the end portions do not interfere with each other at the time of bending application, and the third is located above the interfered portion. No stress that pushes up the oxide superconducting wire.

Further, the oxide superconducting wire connecting structure according to the present invention includes the third oxide superconducting wire of the third oxide superconducting wire in the non-bonded region formed at the longitudinal ends in the first and second overlapping portions. The longitudinal length of the non-joining region formed on the end side is compared with the longitudinal length of the non-joining region formed on the end side of the first or second oxide superconducting wire. It is characterized by being long.
When bending along the stacking direction is applied to the connection structure, the load is greatest on the end side of the third oxide superconducting wire. Therefore, by making the longitudinal length of the non-joining region on the end side of the third oxide superconducting wire longer than the length of the non-joining region on the end side of the first or second oxide superconducting wire, The load concerning the connection structure can be reduced more effectively.

Further, the oxide superconducting wire connecting structure according to the present invention is characterized in that two or more joining regions are formed in the overlapped portion, and the joining regions are separated from each other by a non-joining region.
Due to the structure in which two or more joining regions are formed and the joining regions are separated from each other by a non-joining region, a part of the conductive joining material flows into the non-joining region formed between the joining regions, and the overlapping portion Therefore, the conductive bonding material is not locally thickly formed outside the overlapping portion. That is, no locally weak portion is generated.

In the connection structure of the oxide superconducting wire of the present invention, the end surfaces of the end portions of the first and second oxide superconducting wires close to the joining region are orthogonal to the longitudinal direction of the oxide superconducting wires, In the joining region, an oblique side portion inclined in plan view with respect to the longitudinal direction of the oxide superconducting wire is formed at the boundary with the non-joining region.
A configuration in which the end portion on the non-joining region side of the joining region is partially joined in the width direction of the oxide superconducting wire and the unjoined region by forming the oblique side portion in the joining region It becomes. By providing this region, an unbonded region is generated on the end side of the bonded region. Therefore, when bending is applied to the bonded portion of the oxide superconducting wire, a region that is freed from stress is generated. The stress applied to the oxide superconducting layer close to is reduced. For this reason, it is possible to provide a connection structure in which the superconducting characteristics are not easily deteriorated even if bending acts on the joint portion between the oxide superconducting wires.

The connection structure of the oxide superconducting wire according to the present invention is characterized in that an auxiliary joining region narrower than the non-joining region is formed in the non-joining region on the side opposite to the joining region side.
When bending acts on the joints between the oxide superconducting wires, the auxiliary joining region connects the oxide superconducting wires in addition to the joining region to cause deformation following the bending, so the oxide superconducting wire outside the auxiliary joining region. It is possible to suppress the phenomenon that the gap between the end portion side of the oxide and the oxide superconducting wire opposite to the gap is opened more than necessary. For this reason, even if it is a case where a bending acts on the junction part of oxide superconducting wire, the connection structure which cannot generate | occur | produce the open space | gap on the edge part side of an oxide superconducting wire can be provided.

Moreover, the superconducting device of the present invention is characterized by having a connection structure of the oxide superconducting wire.
According to the present invention, it becomes possible to improve the protection performance of a superconducting device against a mechanical load, so that a superconducting device having higher reliability than the conventional one can be realized.

The method for connecting oxide superconducting wires according to the present invention includes the steps of forming first and second oxide superconducting wires formed by laminating an intermediate layer, an oxide superconducting layer, and a stabilizing layer on a tape-like substrate. And a stabilizing layer surface of the first oxide superconducting wire or the second oxide superconducting wire, and the end portions of the first oxide superconducting wire and the second oxide superconducting wire. 1 mm at a position corresponding to the end portion of the first oxide superconducting wire and the end portion of the second oxide superconducting wire in the portion where the wires cover each other when the adjacent stabilizing layers are opposed to each other. The step of disposing a masking material with a width of 100 mm or less, the step of disposing a conductive bonding material in a space formed between the masking materials, the first oxide superconducting wire and the second oxide superconducting Joining the wire, Characterized by a step of removing the serial masking material.
The non-bonding region at the inner end of the overlapping portion suppresses the conductive bonding material from protruding from the overlapping portion. Therefore, it does not solidify on both outer sides of the overlapped portion, and since the joint portion made of the conductive joint material is not locally thickened in the connection structure, a portion that is not easily bent is not generated.

Also, the method for connecting oxide superconducting wires of the present invention comprises first, second and third oxide superconducting wires comprising a tape-like base material laminated with an intermediate layer, an oxide superconducting layer and a stabilizing layer. Aligning the side on which the oxide superconducting layer is formed with respect to the base material of the first and second oxide superconducting wires, and adjoining the ends to be connected with a predetermined gap therebetween. The first oxide superconductor stabilization layer is bridged between the first oxide superconductor wire stabilization layer and the first oxide superconductor stabilization layer so as to straddle the adjacent ends. And when the stabilizing layers in the vicinity of the end portions of the third oxide superconducting wire are opposed to each other, the end portions of the first oxide superconducting wire and the third oxide are covered with each other. The width corresponding to the end of the superconducting wire is 1 mm or more and 100 mm or less. The step of arranging the masking material and the second oxide superconductivity at the portion where the wires cover each other when the stabilizing layers in the vicinity of the ends of the second and third oxide superconducting wires are opposed to each other. A step of disposing a masking material with a width of 1 mm or more and 100 mm or less at a position corresponding to an end of the wire and the end of the third oxide superconducting wire, and a conductive bonding material in a space formed between the masking materials Disposing, joining the first oxide superconducting wire and the third oxide superconducting wire, joining the second oxide superconducting wire and the third oxide superconducting wire, and And a step of removing the masking material.
According to the present invention, since the pair of oxide superconducting wires to be connected are arranged in the same stacking direction, it is possible to configure a connection structure in which the oxide superconducting wire is not reversed in the connection portion. Moreover, the non-joining region at the inner end of the overlapping portion suppresses the conductive bonding material from protruding from the overlapping portion. Therefore, it does not solidify on both outer sides of the overlapped portion, and since the joint portion made of the conductive joint material is not locally thickened in the connection structure, a portion that is not easily bent is not generated. Furthermore, by arranging the end portions of the first and second oxide superconducting wires apart from each other, the end portions do not interfere with each other at the time of bending application, and the third is located above the interfered portion. No stress that pushes up the oxide superconducting wire.
Note that if the length of the non-bonded region is less than 1 mm, it is difficult to insert the masking material, and the non-bonded region may not be reliably ensured. Moreover, when it exceeds 100 mm, a connection part becomes long and the handling of a connection structure worsens and is unpreferable.

In the method of connecting oxide superconducting wires according to the present invention, the first and third oxide superconducting wires and the stabilization layers in the vicinity of the end portions of the second and third oxide superconducting wires are opposed to each other. In some cases, the width of the masking material arranged on the end side of the third oxide superconducting wire is arranged on the end side of the first or second oxide superconducting wire in the portion where the wires are covering each other. It is characterized by being longer than the width of.
When bending along the stacking direction is applied to the connection structure, the load is greatest on the end side of the third oxide superconducting wire. Therefore, by making the longitudinal length of the non-joining region on the end side of the third oxide superconducting wire longer than the length of the non-joining region on the end side of the first or second oxide superconducting wire, The load concerning the connection structure can be reduced more effectively. Such a non-bonding region can be formed by the masking material arrangement method as described above.

Also, the oxide superconducting wire connecting method of the present invention is characterized in that the overlapping portion is masked, and both sides thereof are bonded by the conductive bonding material to form a bonding region.
According to the present invention, it is possible to form a structure in which the bonding regions are separated by the non-bonding region, whereby a part of the conductive bonding material flows to the non-bonding region formed between the bonding regions, Since it does not protrude outside the overlapping portion, the conductive bonding material is not locally thickly formed outside the overlapping portion. That is, no locally weak portion is generated.

The connection method of the oxide superconducting wire of the present invention uses, as the oxide superconducting wire, an oxide superconducting wire in which the end surface on the side close to the joining region is orthogonal to the longitudinal direction of these oxide superconducting wires. In the joining region, a joining region having an oblique side inclined in plan view with respect to the longitudinal direction of the oxide superconducting wire is formed at the boundary with the non-joining region.
By forming the hypotenuse in the bonding region, a configuration is formed in which the end of the bonding region on the non-bonding region side is mixed with a region that is partially bonded in the width direction of the oxide superconducting wire and a region that is not bonded it can. By providing this region, a non-bonded region is generated on the bonding region end side, so that when bending stress is applied to the bonded portion of the oxide superconducting wire, a region that is freed from stress application is generated. Stress concentration on the oxide superconducting layer close to the region can be reduced. For this reason, it is possible to provide a connection structure in which the superconducting characteristics are not easily deteriorated even if bending acts on the joint portion between the oxide superconducting wires.

The method for connecting oxide superconducting wires according to the present invention is characterized in that in the non-joining region, an auxiliary joining region narrower than the non-joining region is formed on the side opposite to the joining region side.
Since a structure with an auxiliary junction region can be manufactured, when bending acts on the junction between oxide superconducting wires, the auxiliary junction region joins the oxide superconducting wires in addition to the junction region to cause deformation following the bending. A structure can be obtained. With this structure, it is possible to suppress a phenomenon in which a gap between the end of the oxide superconducting wire outside the auxiliary junction region and the opposing oxide superconducting wire is opened more than necessary. For this reason, even if it is a case where a bending acts on the junction part of oxide superconducting wire, the connection structure which cannot generate | occur | produce the open space | gap on the edge part side of an oxide superconducting wire can be provided.

  According to the present invention, the non-bonding region is formed at least one of the end portions in the overlapping portion in the connection portion. The non-bonding region at the inner end of the overlapping portion suppresses the conductive bonding material from protruding from the overlapping portion. Therefore, it does not solidify on both outer sides of the overlapped portion, and since the joint portion made of the conductive joint material is not locally thickened in the connection structure, a portion that is not easily bent is not generated.

It is a schematic diagram which shows the oxide superconducting wire which concerns on this invention, and its edge part. It is a schematic diagram which shows 1st Embodiment of the connection structure which concerns on this invention, Fig.2 (a) is a front schematic diagram, FIG.2 (b) is a cross-sectional schematic diagram. The modification of 1st Embodiment of the connection structure which concerns on this invention is represented, FIG. 3 (a), (b) is a front schematic diagram of each modification. It is a schematic diagram which shows 2nd Embodiment of the connection structure which concerns on this invention, Fig.4 (a) is a front schematic diagram, FIG.4 (b) is a cross-sectional schematic diagram. The 1st modification of 2nd Embodiment of the connection structure which concerns on this invention is represented, Fig.5 (a), (b), (c) is a front schematic diagram of the 2nd and 3rd modification, respectively. is there. The manufacturing method of the connection structure which concerns on this invention is represented, Fig.6 (a) is a front schematic diagram of a manufacturing method, FIG.6 (b) is a front schematic diagram of the modification of a manufacturing method. It is a cross-sectional schematic diagram showing the other modification of 1st Embodiment of the connection structure which concerns on this invention. It is the elements on larger scale of the modification shown in FIG. It is a cross-sectional schematic diagram showing the 4th modification of 2nd Embodiment of the connection structure which concerns on this invention. FIG. 10 is a partially enlarged plan sectional view of a fourth modification shown in FIG. 9. It is a partial expanded plane sectional view showing the 5th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 6th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 7th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 8th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 9th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 10th modification of a 2nd embodiment of the connection structure. It is a partial expanded plane sectional view showing the 11th modification of 2nd Embodiment of the connection structure. It is a partial section schematic diagram showing an example of a superconducting cable. It is sectional drawing which shows an example of a superconducting fault current limiter. An example of a superconducting motor is shown, FIG. 20A is a partial cross-sectional view showing the overall configuration, and FIG. 20B is a schematic diagram showing the positional relationship of each component. An example of a superconducting coil is shown, FIG. 21A is a perspective view showing a laminated body of superconducting coils, and FIG. 21B is a perspective view showing a single superconducting coil. It is a graph which shows the result of the bending test of an Example and a comparative example. It is a graph which shows the result of the bending test of an Example and a comparative example. It is a graph which shows the result of the bending test of an Example and a comparative example. It is sectional drawing which shows the connection structure of the oxide superconducting wire as a prior art example.

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

(Oxide superconducting wire)
FIG. 1 is a schematic diagram showing an end 1a of an oxide superconducting wire 1 according to the present invention. Based on FIG. 1, each component of the tape-shaped oxide superconducting wire 1 is demonstrated in detail. However, the present invention is not limited to the following embodiments.
The oxide superconducting wire 1 has a structure in which an intermediate layer 11, an oxide superconducting layer 12, a first stabilizing layer 13, and a second stabilizing layer 14 are laminated on a tape-shaped substrate 10. In the present embodiment, the metal constituting the second stabilization layer 14 also serves as a metal layer that covers the outer periphery of the oxide superconducting wire 1.

  The base material 10 may be any material that can be used as a base material for a normal oxide superconducting wire, and is preferably a long tape having flexibility. In addition, the material used for the base material 10 preferably has a metal having high mechanical strength, heat resistance, and easy to be processed into a wire, for example, a nickel alloy such as stainless steel or hastelloy. And various heat-resistant metal materials, or materials in which ceramics are arranged on these metal materials. Among them, Hastelloy (trade name, manufactured by Haynes, USA) is preferable as a commercial product. This kind of Hastelloy includes Hastelloy B, C, G, N, W, etc., which have different amounts of components such as molybdenum, chromium, iron, cobalt, etc., and any kind can be used here. Moreover, what is necessary is just to adjust the thickness of the base material 10 suitably according to the objective, and is 10-500 micrometers normally, Preferably it is 20-200 micrometers.

As the intermediate layer 11, a structure in which a diffusion prevention layer, a bed layer, an alignment layer, and a cap layer are laminated in this order can be applied.
As a result of heat treatment when forming another layer on the upper surface of this layer, the diffusion preventing layer diffuses part of the constituent elements of the base material 10 when the base material 10 or other layers receive a thermal history. And it has a function which suppresses mixing into the oxide superconducting layer 12 side as an impurity. The specific structure of the diffusion preventing layer is not particularly limited as long as it can exhibit the above-described function, but Al ₂ O ₃ , Si ₃ N ₄ , or GZO (which has a relatively high effect of preventing contamination of impurities) A single layer structure or a multilayer structure composed of Gd ₂ Zr ₂ O ₇ ) or the like is desirable.

The bed layer is used to suppress the reaction of the constituent elements at the interface between the base material 10 and the oxide superconducting layer 12 and to improve the orientation of the layer provided on the upper surface than this layer. The specific structure of the bed layer is not particularly limited as long as it can exhibit the above functions, but Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ , Dy ₂ O ₃ , Er ₂ O, which have high heat resistance. ₃ , a single layer structure or a multilayer structure composed of rare earth oxides such as Eu ₂ O ₃ and Ho ₂ O ₃ is desirable.

The alignment layer controls the crystal orientation of the cap layer and the oxide superconducting layer 12 formed thereon, suppresses the constituent elements of the substrate 10 from diffusing into the oxide superconducting layer 12, 10 and the oxide superconducting layer 12 have a function of reducing a difference in physical characteristics such as a coefficient of thermal expansion and a lattice constant. The material of the alignment layer is not particularly limited as long as it can express the above function, but when a metal oxide such as Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ) is used, In an ion beam assisted vapor deposition method (hereinafter also referred to as IBAD method), which will be described later, a layer having high crystal orientation is obtained, and the crystal orientation of the cap layer and the oxide superconducting layer 12 is improved. This is particularly suitable.

The cap layer is used when controlling the crystal orientation of the oxide superconducting layer 12 more strongly than the orientation layer, diffusing elements constituting the oxide superconducting layer 12 into the intermediate layer 11, or laminating the oxide superconducting layer 12. And a function of suppressing the reaction between the gas to be generated and the intermediate layer 11. The material of the cap layer is not particularly limited as long as it can exhibit the above functions, but is CeO ₂ , LaMnO ₃ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , ZrO ₂ , Ho ₂ O _3. From the viewpoint of lattice matching with the oxide superconducting layer 12, metal oxides such as Nd ₂ O ₃ and YSZ are preferable. Among them, CeO ₂ and LaMnO ₃ are particularly preferable because a layer having a higher degree of orientation than that of the intermediate layer 11 can be obtained.
Here, when CeO ₂ is used for the cap layer, the cap layer may include a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.

The oxide superconducting layer 12 has a function of flowing current when in the superconducting state. As the material used for the oxide superconducting layer 12, a material composed of an oxide superconductor having a generally known composition can be widely applied. For example, copper such as RE-123 series superconductor, Bi series superconductor, etc. Examples include oxide superconductors. The composition of the RE-123 series superconductor is, for example, REBa ₂ Cu ₃ O _(7-x) (RE represents a rare earth element such as Y, La, Nd, Sm, Er, Gd, and x represents oxygen deficiency). mentioned, _{specifically, Y123 (YBa 2 Cu 3 O} (7-x)), Gd123 (GdBa 2 Cu 3 O (7-x)) and the like. The composition of the Bi-based superconductor, for _{example, Bi 2 Sr 2 Ca n-} 1 Cu n O 4 + 2n + δ (n is the number of layers of CuO _2, [delta] represents an excess oxygen.) Include. In this copper oxide superconductor, although the base material is an insulator, it becomes a superconductor by taking in oxygen, and has the property of exhibiting superconducting properties. Here, the material of the oxide superconducting layer 12 used in the present invention is a copper oxide superconductor. Unless otherwise specified, the material used for the oxide superconducting layer 12 is a copper oxide superconductor.

  The first stabilization layer 13 bypasses an overcurrent generated at the time of an accident, suppresses a chemical reaction occurring between the oxide superconducting layer 12 and a layer provided on the upper surface of this layer, and an element of one layer It has a function of preventing the superconducting properties from being deteriorated due to a part of the material entering the other layer side and breaking the composition. Moreover, in order to make it easy to take in oxygen to the oxide superconducting layer 12, it has a function which permeate | transmits oxygen easily at the time of a heating. For this reason, a material mainly composed of Ag, such as Ag or an Ag alloy, is used for the first stabilization layer 13. The material of the first stabilization layer 13 used in the present invention is Ag. Hereinafter, unless otherwise specified, the material used for the first stabilization layer 13 is Ag.

  The second stabilization layer 14 laminated on the first stabilization layer 13 is made of a highly conductive metal material, and the oxide superconducting layer 12 attempts to transition from the superconducting state to the normal conducting state for some reason. Sometimes, it functions as a bypass along with the first stabilizing layer 13 where the current of the oxide superconducting layer 12 commutates. The first stabilization layer 13 can be regarded as a part of the second stabilization layer 14 due to its function.

The metal material constituting the second stabilization layer 14 is not particularly limited as long as it has good conductivity, but is not limited to copper alloys such as copper, brass (Cu—Zn alloy), Cu—Ni alloy, stainless steel, and the like. It is preferable to use a material made of a relatively inexpensive material such as copper, and copper is preferable because it has high conductivity and is inexpensive. Further, when the oxide superconducting wire 1 is used for a superconducting fault current limiter, the second stabilization layer 14 is used to instantaneously suppress an overcurrent generated when a quench occurs and the state transitions to a normal conducting state. In the case of this application, examples of the material used for the second stabilization layer 14 include a high resistance metal such as a Ni-based alloy such as Ni—Cr.
The thickness of the 2nd stabilization layer 14 is not specifically limited, Although it can adjust suitably, it can be 10-300 micrometers.

  The method for forming the second stabilization layer 14 is not particularly limited, but in the present embodiment, a metal tape made of a highly conductive material such as copper is attached to the first stabilization layer via a conductive bonding material (not shown) such as solder. It is formed by being laminated on the stabilization layer 13. The second stabilization layer 14 covers the entire circumference of the laminate 15 in which the base material 10, the intermediate layer 11, the oxide superconducting layer 12, and the first stabilization layer 13 are laminated.

  When solder is used as a conductive bonding material (not shown) used when a metal tape is stuck on the first stabilization layer 13, the solder is not particularly limited, and a conventionally known solder can be used. . For example, lead-free solder, Pb-Sn alloy alloy, Sn, Sn—Ag alloy, Sn—Bi alloy, Sn—Cu alloy, Sn—Zn alloy, etc. Crystal solder, low-temperature solder, and the like can be mentioned, and these solders can be used singly or in combination of two or more. Among these, it is preferable to use solder having a melting point of 300 ° C. or less. Thereby, since it becomes possible to solder a metal tape and the 1st stabilization layer 13 at the temperature of 300 degrees C or less, it can suppress that the characteristic of the oxide superconducting layer 12 deteriorates with the heat of soldering.

  The second stabilization layer 14 is attached to the first stabilization layer 13 via solder, and the base material 10, the intermediate layer 11, the oxide superconducting layer 12, and the first stabilization layer 13 are laminated. The entire periphery of the laminate 15 thus formed is covered. That is, the second stabilization layer 14 covers the peripheral surface of the laminate 15 excluding the central portion of the back surface on the side where the intermediate layer 11 is not formed in the base material 10 so as to form a C-shaped cross section. . The second stabilization layer 14 can be formed as a metal layer by forming a metal tape with a roll or the like and depositing it around the laminate 15. The central portion on the back surface side of the substrate 10 that is not covered with the second stabilization layer 14 is covered with the solder layer 16, and the solder layer 16 fills the recess formed by the edges of the second stabilization layer 14. It is formed as follows.

The outer periphery of the oxide superconducting wire 1 is covered with a metal layer (second stabilizing layer 14) made of a metal tape or the like and the solder layer 16, thereby preventing moisture from entering from the side surface of the oxide superconducting wire 1. Further, deterioration of the oxide superconducting layer 12 can be prevented.
In addition to forming the metal tape so as to cover the peripheral surface of the laminate 15 as described above, the entire outer periphery of the laminate 15 is covered by plating, and the metal on the outer periphery of the laminate 15 is covered. The layer and the second stabilization layer 14 may be integrally formed. In this case, by setting the thickness of the plating layer to 10 μm or more, a plating layer without a pinhole can be formed, and moisture can be reliably prevented from entering.

  Here, as described above, the oxide superconducting wire 1 in which a metal tape or a plating layer is formed as the second stabilization layer 14 is exemplified. However, the oxide superconducting wire of the present invention is not limited to this. For example, the oxide superconducting wire does not have the second stabilizing layer 14, that is, only the first stabilizing layer 13 serves as a stabilizing layer. It may be a configuration.

(First embodiment)
Hereinafter, an embodiment of a connection structure according to the present invention will be described with reference to the drawings.
A connection structure 30 in which the first and second oxide superconducting wires 2 and 3 according to the first embodiment of the present invention are connected to each other will be described with reference to FIG.
In addition, the 1st and 2nd oxide superconducting wire 2 and 3 connected in the connection structure 30 of this embodiment are the same forms as the oxide superconducting wire 1 demonstrated based on FIG.

As shown in FIGS. 2A and 2B, the connection structure 30 is a structure that connects the first oxide superconducting wire 2 and the second oxide superconducting wire 3. second oxide superconducting wire 2,3 another end 2a, the second stabilizing layer 14 between the 3a near to face, are arranged to form a superposition portion 50 of length H _50, the superimposed A joining region 51 located at the center in the longitudinal direction of the mating portion 50 is joined by the conductive joining material 22. In addition, non-joined regions 52 and 52 that are not joined are formed on both sides of the joining region 51 that is joined by the conductive joining material 22 in the overlapping portion 50. 2A and 2B, the bonding region 51 is a region represented as a longitudinal length H ₅₁ , and a region represented as a longitudinal length H ₅₂ of the non-joining region 52. It is.

A connection method for connecting the first and second oxide superconducting wires 2 and 3 to form the connection structure 30 will be described below.
First, the second stabilization layers 14 and 14 in the vicinity of the end portions 2a and 3a of the first and second oxide superconducting wires 2 and 3 are opposed to each other to form an overlapping portion 50. . At this time, in the overlapping portions 50, the longitudinal ends, masking non-bonding regions 52, 52 by a predetermined length H ₅₂ only masking material. Next, the portions other than the non-bonding regions (masking portions) 52, 52 of the overlapping portion 50 are connected by bonding with the conductive bonding material 22. When solder is used as the conductive bonding material 22, masking is performed when the overlapping portion 50 is formed, and a solder foil is sandwiched between the bonding regions 51 located at the center in the longitudinal direction of the overlapping portion 50 to overlap the overlapping portions 50. By heating the part 50 while applying pressure, the solder is melted and joined. In this case, the masking material is removed as necessary after the solder is fixed, and the non-joining regions 52 and 52 are formed.
In the case where solder is used as the conductive bonding material 22, the apparatus and method for pressurizing and heating the connection portion will be described in detail later together with the connection method of the second embodiment.
The masking material is not particularly limited as long as the solder is not fixed, and for example, a tape or sheet made of Kapton (registered trademark), Teflon (registered trademark), or the like can be used.

  As shown in FIG. 2B, in the connection structure 30, the oxide superconducting layer 12 is laminated on the base material 10 in the first oxide superconducting wire 2 and the second oxide superconducting wire 3. It is desirable to overlap with the sides facing each other. By overlapping in this way, the connection structure 30 having a low electrical resistance at the connection portion can be configured.

  As described above, solder can be used as the conductive bonding material 22 for bonding the first and second oxide superconducting wires 2 and 3. As the conductive bonding material 22, the same solder as the conductive bonding material used when a metal tape is attached onto the first stabilization layer 13 can be used.

The overlapping portion 50 in the vicinity of the end portions 2a and 3a of the first and second oxide superconducting wires 2 and 3 to be connected has a longitudinal length H51 of the joining region ₅₁ and a longitudinal length of the non-joining regions 52 and 52. This is the sum of the direction lengths H ₅₂ and H ₅₂ .
By increasing the length H ₅₁ in the longitudinal direction of the joining region 51, the first oxide superconducting wire 2 to the second oxide superconducting wire 3 or the second oxide superconducting wire 3 to the first oxide In the current path to the superconducting wire 2, the cross-sectional area of the conductive bonding material 22 in the current direction can be increased, and the resistance value at the connection portion of the connection structure 30 can be suppressed as a whole. Therefore, the length H ₅₁ in the longitudinal direction of the joining region 51 is preferably longer from the viewpoint of the electrical resistance of the connection portion, and specifically, it is desirably 10 mm or more. However, when the length H ₅₁ in the longitudinal direction of the joining region 51 exceeds 120 mm, the connecting portion becomes too long, and the flexibility of the connecting structure 30 is deteriorated. Therefore, the length H ₅₁ in the longitudinal direction of the joining region 51 is desirably 120 mm or less.

The length H ₅₂ in the longitudinal direction of the non-bonded regions 52, ₅₂ is preferably 1 mm or more and 100 mm or less. When the length H ₅₂ of the non-bonding region 52 is less than 1 mm, the insertion of the masking material is difficult, there is a possibility that the non-bonding region 52 is not reliably ensured. If the non-bonding region 52 is not secured reliably, excess solder accumulates at the end of the overlapping portion 50 and solidifies, and the thickness of the conductive bonding material 22 locally increases at the end of the overlapping portion 50. Therefore, when the connection structure 30 is bent, stress concentrates at the end of the overlapping portion 50, and the crystal structure of the oxide superconducting layer 12 may be damaged. That is, the structure is weak against bending.
On the other hand, when the length H ₅₂ in the longitudinal direction of the non-bonded region 52 exceeds 100 mm, the connecting portion becomes long, and the handling of the connection structure 30 is deteriorated.

(Modification of the first embodiment)
FIGS. 3A and 3B are schematic views showing connection structures 31 and 32 which are first and second modifications of the first embodiment of the present invention. In addition, about the component same as the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The connection structures 31 and 32 that are the first and second modifications of the first embodiment are structures that connect the first oxide superconducting wire 2 and the second oxide superconducting wire 3, and Compared with the connection structure 30 of the embodiment, the positional configurations of the bonding region 51 and the non-bonding region 52 in the overlapping portion 50 are different.
Hereinafter, the connection structures 31 and 32 which are the first and second modifications of the first embodiment will be described with reference to FIGS.

The overlapping portions 50 in the connecting structure 31 of the first modification shown in FIG. 3 (a), junction region formed over the first oxide superconducting wire second end 2a length from H ₅₁ 51 is joined by the conductive joining material 22. Further, an the superposed section 50, over the second oxide superconducting wire 3 of the end portion 3a to the length H _52, non-bonding region 52 which is not joined by the conductive joining member 22 is formed Yes.

  Since the non-bonding region 52 is formed in the vicinity of the end 3 a of the second oxide superconducting wire 3, the conductive bonding material 22 does not protrude and solidify outside the overlapping portion 50. On the other hand, the non-bonding region 52 is not formed on the end portion 2a side of the first oxide superconducting wire 2 in the overlapped portion 50, and the conductive bonding material 22 overflows and protrudes in that portion. An overflow portion 53 in which the bonding material 22 is thick is formed.

When bending is applied to the connection structure 31 so that the first oxide superconducting wire 2 is on the outside and the second oxide superconducting wire 3 is on the inside, the overflow portion 53 is subjected to the first and second oxidations. Tensile stress is applied in the stacking direction of the superconducting wire rods 2 and 3. The overflow portion 53 has high rigidity because the conductive bonding material 22 is formed thick, and if a tensile stress is applied to the overflow portion 53, an excessive load is applied to the oxide superconducting layer 12 in the vicinity thereof, and the superconducting characteristics are deteriorated. There is a fear.
However, when compressive stress is applied, the load on the oxide superconducting layer 12 is almost the same as the portion where the conductive bonding material 22 is uniformly formed. Therefore, the connection structure 31 is unlikely to deteriorate in superconducting characteristics against bending in a direction in which the overflow portion 53 is subjected to compressive stress.
In other words, in the present embodiment, the connection structure 31 is applied with bending so that the first oxide superconducting wire 2 is on the inside and the second oxide superconducting wire 3 is on the outside (FIG. 3A). In the case where the overlapping portion 50 is bent in an inverted U shape so that it becomes the uppermost point), the superconducting characteristics are hardly deteriorated.

In the connection structure 32 of the second modified example shown in FIG. 3B, a non-joining region 52 and a joining region 51 are sequentially formed in the overlapping portion 50 in the longitudinal direction. The non-joining area | region 52 is formed in the longitudinal direction both ends. The three non-joining regions 52 are each formed over a region having a length H _{52 in} the longitudinal direction, and the two joining regions 51 are each formed over a region having a length H _{51 in} the longitudinal direction. .

  The connection structure 32 can obtain the same effects as various effects obtained by the connection structure 30 of the first embodiment. Further, since the bonding regions 51 and 51 are separated from each other by the non-bonding region 52, a part of the conductive bonding material 22 flows to the non-bonding region 52 formed between the bonding regions 51 and 51. Further, it is possible to suppress the protrusion of the overlapping portion 50 from the outside, and the conductive bonding material 22 is not locally thickly formed outside the overlapping portion 50. That is, no locally weak portion is generated.

(Second Embodiment)
Hereinafter, an embodiment of a connection structure according to the present invention will be described with reference to the drawings.
A connection structure 33 in which the first and second oxide superconducting wires 4 and 5 according to the second embodiment of the present invention are connected to each other will be described with reference to FIG. The same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.
In addition, the 1st and 2nd oxide superconducting wire 4 and 5 connected in the connection structure 33 of this embodiment are the same structures as the oxide superconducting wire 1 demonstrated based on FIG.

As shown in FIGS. 4A and 4B, the connection structure 33 connects the first oxide superconducting wire 4 and the second oxide superconducting wire 5 via the third oxide superconducting wire 6. It has a configuration.
The connection structure 33 according to the second embodiment is different from the connection structure 30 according to the first embodiment described above in one end of the first oxide superconducting wire 4 (in the vicinity of the end 4a) and one end of the third oxide superconducting wire 6. (Applied to and near the first end portion 6a), and connected to the other end of the third oxide superconducting wire 6 (near the second end portion 6b) and one end (end portion) of the second oxide superconducting wire 5. 5a)) and connected.

A method for forming the connection structure 33 according to the second embodiment will be described with reference to FIGS.
First, the first and second oxide superconducting wires 4 and 5 are adjacent to each other with the end portions 4a and 5a to be connected apart from each other by a distance e. At this time, the first and second oxide superconducting wires 4 and 5 are arranged with the bases 10 and 10 on the side where the oxide superconducting layers 12 and 12 are formed.

Next, the third oxide superconducting wire 6 is bridged across the end portions 4a and 5a of the adjacent first and second oxide superconducting wires 4 and 5. As a result, the first oxide superconducting wire 4, the first overlapping portion 60 where the third oxide superconducting wire 6 overlaps, the second oxide superconducting wire 5, and the third oxide superconducting wire 6. Are formed with the second overlapping portion 70. The third oxide superconducting wire 6 and the first and second oxide superconducting wires 4 and 5 are overlapped with the base 10 facing the side on which the oxide superconducting layer 12 is laminated. 4A and 4B, the first overlapping portion 60 is a region represented as a longitudinal length H ₆₀ , and the second overlapping portion 70 has a longitudinal length H An area represented as ₇₀ . Further, when the first overlapping portion 60 is formed, the portions corresponding to the non-bonding regions 62 and 72 are masked next. Further, the bonding regions 61 and 72 are bonded by the conductive bonding material 22.

The lengths H ₆₁ and H ₇₁ in the longitudinal direction of the joining regions 61 and 71 joined by the conductive joining material 22 are the same as the connection structure 30 of the first embodiment in the electrical resistance and flexibility of the connection structure 33. From the viewpoint of 10 to 120 mm, it is desirable.
In addition, the lengths H ₆₂ and H ₇₂ in the longitudinal direction of the non-bonded regions ₆₂ and ₇₂ are preferably 1 mm or more and 100 mm or less from the viewpoint of masking workability and handling of the connection structure 33.
The distance e between the end portions 4a and 5a to be connected to the first and second oxide superconducting wires 4 and 5 is preferably 1 mm or more. By arranging the first and second oxide superconducting wires 4 and 5 apart from each other by 1 mm or more, the connection structure 33 is bent such that the third oxide superconducting wire 6 is outside (FIG. 4A ), The ends 4a and 5a of the first and second oxide superconducting wires 4 and 5 do not interfere with each other when an inverted U-shaped bend in which the center is the top point is applied. No stress is generated to push up the third oxide superconducting wire 6 located above the interfering portion.

  In addition, as shown in FIG. 4B, in the connection structure 33, the first oxide superconducting wire 4 and the third oxide superconducting wire 6 are composed of the oxide superconducting layer with respect to the base materials 10 and 10. It is desirable that the sides on which the layers 12 and 12 are stacked are opposed to each other. Further, the third oxide superconducting wire 6 and the second oxide superconducting wire 5 may be overlapped with the bases 10 and 10 facing each other where the oxide superconducting layers 12 and 12 are laminated. desirable. By overlapping in this way, the connection structure 33 having a low electrical resistance at the connection portion can be configured. In addition, since the first oxide superconducting wire 4 and the second oxide superconducting wire 5 to be connected are laminated in the same direction, the first and second oxide superconducting wires 4 are connected at the connecting portion. There is no inversion of the front and back of 5 and handling becomes easy.

The connection structure 33 of the second embodiment can obtain the same effects as various effects obtained by the connection structure 30 of the first embodiment.
In addition, since the first oxide superconducting wire 4 and the second oxide superconducting wire 5 to be connected are laminated in the same direction, the first and second oxide superconducting wires 4 are connected at the connecting portion. 5 is easy to handle.

(Modification of the second embodiment)
FIGS. 5A, 5 </ b> B, and 5 </ b> C are schematic views illustrating connection structures 34, 35, and 36 that are first to third modifications of the second embodiment of the present invention. In addition, about the component same as the above-mentioned 2nd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. The connection structures 34, 35, and 36, which are the first to third modifications of the second embodiment, include the first oxide superconducting wire 4 and the second oxide superconducting wire 5 as the third oxide superconducting wire. 6, compared with the connection structure 33 of the second embodiment, the bonding regions 61 and 71 and the non-bonding regions 62 and 72 in the first and second overlapping portions 60 and 70, respectively. The position configuration differs.
Hereinafter, the connection structures 34, 35, and 36, which are modifications of the second embodiment, will be described with reference to FIGS. 5 (a), (b), and (c).

  In the connection structure 34 of the first modified example shown in FIG. 5A, the first and second superposed portions 60 and 70 have end portions of the first and second oxide superconducting wires 4 and 5, respectively. Since the non-bonding regions 62 and 72 are formed in the vicinity of 4a and 5a, the conductive bonding material 22 does not protrude and solidify outside the overlapping portion 50. On the other hand, the first and second overlapping portions 60 are provided. 70, the non-bonding regions 62, 72 are not formed on the first and second end portions 6a, 6b side of the third oxide superconducting wire 6, and the conductive bonding material 22 protrudes in the portion. The overflow parts 63 and 73 in which the conductive bonding material 22 is thick are formed.

When bending is applied to the connecting structure 34 such that the first and second oxide superconducting wires 4 and 5 are inside and the third oxide superconducting wire 6 is outside, the overflow parts 63 and 73 Tensile stress is applied in the stacking direction of the first, second, and third oxide superconducting wires 4, 5, 6. The overflow parts 63 and 73 have high rigidity because the conductive bonding material 22 is formed thick. If tensile stress is applied to the overflow parts 63 and 73, an excessive load is applied to the oxide superconducting layer 12 in the vicinity thereof. There is a risk of deteriorating characteristics.
However, when compressive stress is applied, the load on the oxide superconducting layer 12 is almost the same as the portion where the conductive bonding material 22 is uniformly formed. Therefore, the connection structure 34 is less susceptible to deterioration of the superconducting characteristics against bending in the direction in which the overflow portions 63 and 73 are subjected to compressive stress.
That is, the connection structure 34 is bent so that the first and second oxide superconducting wires 4 and 5 are on the outside and the third oxide superconducting wire 6 is on the inside (in FIG. 5A). In the case where the central portion is bent into a U-shape with the lowest point, the superconducting characteristics are unlikely to deteriorate.

  The connection structure 35 of the second modified example shown in FIG. 5B is bonded at the first and second overlapping portions 60 and 70 as compared with the connection structure 34 of the first modified example. It can be explained that the positional relationship between the regions 61 and 71 and the non-bonded regions 62 and 72 is reversed.

  Compared with the connection structure 34, the connection structure 35 also has a reverse bending direction in which stress in the compression direction is applied to the overflow parts 63 and 73, and a bending direction in which deterioration is unlikely to occur. That is, when bent so that the first and second oxide superconducting wires 4 and 5 are on the inside and the third oxide superconducting wire 6 is on the outside (in FIG. 5B, the central portion is the highest point). In such a case, the superconducting characteristics are hardly deteriorated.

  The connection structure 36 of the third modification shown in FIG. 5C is described based on FIG. 3B in the vicinity of the first and second end portions 6a and 6b of the third oxide superconducting wire 6. The connection structure 32 which is a modification of the first embodiment is continuously connected. Therefore, the same effect as that of the connection structure 32 which is a modification of the first embodiment can be obtained.

(Connection of conductive bonding material: manufacturing method of connection structure)
The bonding of the conductive bonding material 22 is desirably performed by bonding devices 152 and 153 described below with reference to FIGS. 6 (a) and 6 (b). In the description based on FIGS. 6A and 6B, solder is used as the conductive bonding material 22 unless otherwise specified. Moreover, the joining method using this connection apparatus is applicable in the connection structures 30, 31, 32, 33, 34, 35, and 36 described above.

The joining device 152 shown in FIG. 6A is schematically shown from an upper plate 150, a lower plate 155, a pressure device (not shown), and a heater (not shown) that sandwich and pressurize the connection structure 33 from above and below. Composed.
A procedure for joining the connection structure 33 by the joining device 152 will be described below.
First, the first oxide superconducting wire 4 and the second oxide superconducting wire 5 are placed adjacent to each other on the lower plate 155, and a masking material 160 is pasted thereon, and further, solder foil, solder paste, etc. The conductive bonding material 22 is provided in the bonding regions 61 and 71 where the masking material 160 is not applied. Next, the third oxide superconducting wire 6 is bridged across the end portions 4a and 5a of the adjacent first and second oxide superconducting wires 4 and 5, and the upper plate 150 is connected to the third plate The oxide superconducting wire 6 is covered from above, and the protrusion 150 a of the upper plate 150 is disposed so as to cover the third oxide superconducting wire 6. The upper plate 150 is provided with a pressurizing device, and can uniformly pressurize the third oxide superconducting wire 6 downward at a predetermined pressure.

Next, the upper plate 150 and the lower plate 155 are heated above the melting point of the conductive bonding material 22 by a heater. The heat of the upper plate 150 and the lower plate 155 is transmitted to the connection structure 33, and the conductive bonding material 22 is melted. At this time, if the temperature is too high, the oxide superconducting layer 12 (see FIG. 1) is deteriorated. Therefore, it is preferable to perform heating while measuring the temperature of the upper plate 150 and the lower plate 155.
Finally, the heater is turned off and cooled, and after the conductive bonding material 22 is solidified, the upper plate 150 is removed, the connection structure 33 is taken out, and the masking material is removed as necessary.
By using the joining device 152 along the above procedure, the connection structure 33 can be formed without depending on the skill level of the operator.

FIG. 6B shows a joining device 153 that is a modification of the joining device 152 described above. The joining device 153 differs from the joining device 152 in the shape of the upper plate 151.
The upper plate 151 of the joining device 153 has substantially the same longitudinal length as the longitudinal lengths of the joining regions 61 and 71 of the connection structure 33 (H ₆₁ and H ₇₁ in FIGS. 4A and 4B). It has a protrusion 151a.
When the pressing portion 151 a of the upper plate 151 is pressed from above the connection structure 33, only the region where the conductive bonding material 22 is provided is pressed. Therefore, the conductive bonding material 22 in a molten state can be uniformly pressed without being affected by the unevenness and waviness on the surface of the oxide superconducting wire, and the conductive bonding material 22 having a uniform thickness can be formed. it can. In addition, since the portion where the conductive bonding material 22 is to be melted is intensively heated, the energy efficiency is high.

(Other variations of the first embodiment)
FIG. 7 is a schematic diagram showing a connection structure 30A that is a third modification of the first embodiment of the present invention. In addition, about the component same as the above-mentioned 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted. A connection structure 30A, which is a fourth modification of the first embodiment, is a structure that connects the first oxide superconducting wire 2 and the second oxide superconducting wire 3, and the connection structure of the first embodiment. Compared with the body 30, the shape of the joining region 51A and the non-joining regions 52A ₁ and A _{2 in} the overlapping portion 50A is slightly different.
Hereinafter, a connection structure 30A, which is a third modification of the first embodiment, will be described with reference to FIGS.

In the connection structure 30A shown in FIG. 7, the overlapping portion 50A has a conductive region 51A formed over the length H _51A from the end 2a to the end 3a of the first oxide superconducting wire 2. It is formed of the material 22A. Further, an the overlapping portions 50A, a non-bonding region 52A ₁ which are not joined by the conductive joining material 22A over the length H _52A from the first oxide end 2a of the superconducting wire 1 is formed, unbonded area 52A ₂ are formed which are not joined by the second oxide superconducting wire 3 of the end portion 3a from over the length H _52A conductive bonding material 22A.
An end face 2 b formed at the end 2 a of the first oxide superconducting wire 2 is formed so as to be orthogonal to the longitudinal direction of the oxide superconducting wire 2. In addition, that this end surface 2b is orthogonal means that the end surface of the tape-shaped base material 10 used at the time of manufacturing the oxide superconducting wire 2 was formed so as to be orthogonal to the longitudinal direction of the base material 10. It is inherited. Similarly, the end face 3 b of the oxide superconducting wire 3 is formed so as to be orthogonal to the longitudinal direction of the oxide superconducting wire 3.
In the connection structure 30A of the third modified example, the width of the joining region 51A and the width of the non-joining regions 52A ₁ and 52A ₂ are different for each position in the width direction of the oxide superconducting wires 2 and 3. Has been.

As shown in FIG. 8, the joining region 51A provided in the connection structure 30A has a hypotenuse 22a on the end 3a side of the oxide superconducting wire 3 when the joining portion of the oxide superconducting wires 2 and 3 is viewed in plan view. And the hypotenuse 22b is formed on the end 2a side of the oxide superconducting wire 2.
The joining region 51A (conductive joining material 22A) is formed in a parallelogram shape in plan view having the same width as that of the oxide superconducting wires 2 and 3 in a region located between the oblique sides 22a and 22b. In the structure of this example, since the oblique side portion 22a and the oblique side portion 22b are formed in parallel in plan view, the non-joined regions 52A ₁ and 52A ₂ are each formed in a triangular shape in plan view. Therefore, the widths of the non-joining regions 52A ₁ and 52A ₂ are formed so as to be different for each position in the length direction of the oxide superconducting wires 2 and 3. In FIG. 8, a rectangular region K is a rectangular shape including the outer shape of the end portions 2a and 3a of the oxide superconducting wires 2 and 3 in addition to the bonding region 51A and the non-bonding regions 52A ₁ and 52A _{2 formed} by the conductive bonding material 22A. It is expressed as an area.

7, at the end 3a of the oxide superconducting wire 3, as shown in FIG. 8, the width of the non-bonding region 52A ₂ is formed so as to gradually wider toward the end 3a, with distance from the end portion 3a while being formed so as to gradually decrease at the end 2a of the oxide superconducting wire 2, the width of the non-bonding region 52A ₁ is formed so as to gradually wider toward the end 2a, from the end 2a It is formed so that it gradually becomes narrower as it leaves. In other words, the hypotenuse part 22b or the hypotenuse part 22a is formed so that the width of the joining region 51A becomes narrower as it approaches the end part 2a or the end part 3a.
Accordingly, in this example, the width of the bonding region 51A and the width of the non-bonding regions 52A ₁ and 52A ₂ are different for each position in the longitudinal direction of the oxide superconducting wires 2 and 3 on the end 2a side and the end 3a side. However, the non-joining regions 52A ₁ and 52A ₂ are formed so that the maximum length is 1 mm or more and 100 mm or less in the longitudinal direction of the oxide superconducting wires 2 and 3. The inclination angle of the oblique sides 22a and 22b can be adjusted to an arbitrary angle according to the size of the non-bonded regions 52A ₁ and 52A ₂ , and the oblique sides 22a and 22b are not limited to a straight line, but are curved, Any shape such as a staircase may be used.

As an example, in the oxide superconducting wires 2 and 3 as shown in FIG. 8, the region indicated by the arrow H _51A in FIG. 8 is the bonding region 51A, and the white region among the regions indicated by the symbol H _52A is not bonded. The regions 52A ₁ and 51A ₂ and the region filled in gray are part of the joining region joining region 51A.
In the non-bonding regions 52A ₁ and 51A ₂ , as in the case of the previous embodiment, a masking material is provided in a portion corresponding to the non-bonding regions 52A ₁ and 52A ₂ and solder is used as the conductive bonding material 22A. In this case, when the oxide superconducting wires 2 and 3 are joined by sandwiching the solder foil and melting the solder, the regions where the masking material is disposed can be formed as the non-joining regions 52A ₁ and 52A ₂ . As described in the previous embodiment, the masking material such as tape or sheet made of Kapton (registered trademark) or Teflon (registered trademark) does not adhere to the conductive bonding material 22A such as solder. The places become non-joining regions 52A ₁ and 52A ₂ even when the conductive joining material is present. The masking material may be left as it is or may be removed after bonding. Further, if a masking material is disposed in the non-bonding regions 52A ₁ and 52A ₂ and the conductive bonding material 22A such as solder is shaped to match the outer shape of the non-bonding region 51, the non-bonding regions 52A ₁ and 52A ₂ Can have a structure without a conductive bonding material.

Also in the connection structure 30A of this example, the non-joining regions 52A ₁ and 52A ₂ having a maximum length of 1 mm or more and 100 mm or less are formed in the longitudinal direction of the oxide superconducting wires 2 and 3. If the maximum length of _{one of} the non-joining regions 52A ₁ and 52A ₂ is less than 1 mm, it is difficult to insert the masking material, and the non-joining regions 52A ₁ and 52A ₂ may not be ensured reliably. If the non-bonding regions 52A ₁ and 52A ₂ are not ensured, excess solder accumulates and solidifies at the end of the overlapping portion 50, and the thickness of the conductive bonding material 22A is locally at the end of the overlapping portion 50. Therefore, when the connection structure 30A is bent, stress is concentrated at the end of the overlapping portion 50, and the crystal structure of the oxide superconducting layer 12 may be damaged. That is, the structure is weak against bending.

Further, if the maximum length in one longitudinal direction of the non-joining regions 52A ₁ and 52A ₂ exceeds 100 mm, the connecting portion becomes long, and the handling of the connecting structure 30A becomes unfavorable. Since the non-bonded regions 52A ₁ and 52A ₂ having a maximum length of 1 mm or more and 100 mm or less are formed in the longitudinal direction of the oxide superconducting wires 2 and 3, the oxide superconducting wires 2 and 3 are reversed from the state shown in FIG. Even if it is bent in the U-shaped direction, the stress concentration load on the oxide superconducting layer 12 is reduced, and a connection structure 30A having excellent superconducting characteristics that does not cause a decrease in Ic value can be provided.
Furthermore, since the oblique sides 22a and 22b are formed in the joining regions 51A ₁ and 52A _{2 as} in this example, the conductive joining material 22A is formed on the end 2a side and the end 3a side of the oxide superconducting wires 2 and 3. However, the region to be bonded to the oxide superconducting wires 2 and 3 and to restrain the oxide superconducting wires 2 and 3 can be made smaller as it approaches the end portions 2a and 3a. As a result, the amount of strain applied to the oxide superconducting wires 2 and 3 can be reduced. As a result, stress concentration on the oxide superconducting layer 12 around the junction regions 51A ₁ and 52A ₂ can be suppressed, and deterioration of superconducting characteristics can be suppressed.
Further, the shape of the end surfaces 2b and 3b of the oxide superconducting wires 2 and 3 remains at right angles to the longitudinal direction of the wire, and only the oblique sides 22a and 22b of the conductive bonding material 22A are formed. Therefore, there is an effect that can be easily realized.
On the other hand, for example, when the end portions of the oxide superconducting wires 2 and 3 are obliquely cut along the oblique sides 22a and 22b to form the conductive bonding material 22A having the oblique sides 22a and 22b, the oxide Since an extra cutting operation is required to cut the ends of the superconducting wires 2 and 3 obliquely with a cutting device such as a scissors, the oxide superconducting layer 12 is damaged at the time of cutting, or the stabilization layers 13 and 14 are damaged. This may cause problems and may deteriorate the superconducting properties.
In the connection structure 30 </ b> A of this example, it is possible to obtain the same effects as the connection structure 30 of the first embodiment with respect to other functions and effects.

(Other modifications of the second embodiment)
FIG. 9 is a schematic diagram showing a connection structure 33A according to a fourth modification of the second embodiment of the present invention. In addition, about the component same as the above-mentioned 2nd Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
The connection structure 33A according to the fourth modification of the second embodiment is a structure that connects the first oxide superconducting wire 4 and the second oxide superconducting wire 5 via the third oxide superconducting wire 6. It is an example. Compared with the connection structure 33 of the second embodiment described above, the shapes of the joining regions 61A and 71A and the non-joining regions 62A and 72A in the first and second overlapping portions 60 and 70 are different.

  The connection structure 33A of this example is similar to the connection structure 30A of the previous embodiment in one end of the first oxide superconducting wire 4 (in the vicinity of the end 4a) and one end of the third oxide superconducting wire 6. (Applied to and near the first end portion 6a), and connected to the other end of the third oxide superconducting wire 6 (near the second end portion 6b) and one end (end portion) of the second oxide superconducting wire 5. 5a)) and connected. Also in the structure of this example, the end faces 4c, 5c, 6c of the oxide superconducting wires 4, 5, 6 are all formed so as to be orthogonal to the longitudinal direction of the oxide superconducting wires 4, 5, 6.

A short third oxide superconducting wire 6 for connection is disposed so as to straddle the end portions 4a, 5a of the first oxide superconducting wire 4 and the second oxide superconducting wire 5. As a result, the first oxide superconducting wire 4, the first overlapping portion 60 </ b> A where the third oxide superconducting wire 6 overlaps, the second oxide superconducting wire 5, and the third oxide superconducting wire 6. A second overlapping portion 70A is formed. The third oxide superconducting wire 6 is overlapped with the first and second oxide superconducting wires 4 and 5 so that the side on which the oxide superconducting layer 12 is laminated is opposed to the base 10. . In FIG. 9, the first overlapping portion 60A is a region expressed as a longitudinal length H _60A , and the second overlapping portion 70A is a region expressed as a longitudinal length H _70A. is there. Further, when the first overlapping portion 60A is formed, a masking material is disposed in a portion corresponding to the non-bonding regions 62A ₁ , 62A ₂ , 72A ₁ , 72A ₂ to mask the necessary regions, thereby making each non-bonding region 62A ₁ , 62A ₂ , 72A ₁ , 72A ₂ The point of forming the junction region is the same as in the previous example. Further, the bonding region 61A is bonded by the conductive bonding material 22B, and the bonding region 71A is bonded by the conductive bonding material 22C.

The planar shape of the conductive joining material 22B joining the first oxide superconducting wire 4 and the third oxide superconducting wire 6 in the connection structure 33A shown in FIG. 9, the second oxide superconducting wire 5 and The planar shape of the conductive bonding material 22C bonding the third oxide superconducting wire 6 is shown in FIG.
Conductive bonding material 22B is formed in the longitudinal length H _60A and the rectangular region K4 equivalent length of the oxide superconducting wire 4,6 equivalent width and overlapping portions 60A. Conductive bonding material 22B is formed in plan view trapezoidal shape obtained by subtracting the rectangular unbonded regions 62A ₁ and triangular unbonded region 62A ₂ from the rectangular region K4. The boundary portion of the non-bonding region 62A ₂ side of the conductive bonding material 22B is formed oblique side 22a shown in FIG. 10, the straight line portion 22d is formed in the non-bonding region 62A ₁ side. The rectangular region K4 shown in FIG. 10 includes the end portion 4a of the first oxide superconducting wire 4 and the third oxide by combining the joining region 61A and the non-joining regions 62A ₁ and 62A ₂ in the first overlapping portion 60A. It is indicated as a planar view region defined by the end 6a of the superconducting wire 6.

Junction region 71A (conductive bonding material 22C) is formed in the longitudinal length H _70A and the rectangular region K5 equivalent length of the oxide superconducting wire 5, 6 equal width and overlapping portions 70A. Conductive bonding material 22C is formed in plan view trapezoidal shape obtained by subtracting the rectangular unbonded regions 72A ₁ and triangular unbonded region 72A ₂ from the rectangular region K5. The non-bonding region 72A ₂ side of the conductive bonding material 22C is oblique side 22b shown in FIG. 10 is formed, the linear portion 22d is formed in the non-bonding region 72A ₁ side. The oblique side portion 22a and the oblique side portion 22b are arranged so as to be inclined with respect to the longitudinal direction of the wire and parallel to each other when the conductive bonding materials 22B and 22C are viewed in plan as shown in FIG. Yes. The rectangular region K5 shown in FIG. 10 includes the end portion 5a of the second oxide superconducting wire 5 and the third oxide by combining the joining region 71A and the non-joining regions 72A ₁ and 72A ₂ in the second overlapping portion 70A. It is indicated as a planar view region defined by the end 6b of the superconducting wire 6.
As described above, in the connection structure 33A shown in FIG. 9, on both sides of the junction region 61A is non-bonding region 62A ₁ and the non-bonding region 62A ₂ as shown in FIG. 10 are formed on both sides of the junction region 71A the unbonded regions 72A ₁ and the non-bonding region 72A ₂ is formed as shown in FIG. 10.

In the connection structure 33A shown in FIG. 9 and FIG. 10, the oblique side portion 22a is formed in the conductive bonding material 22B, and the oblique side portion 22b is formed in the conductive bonding material 22C. As in the case of the connection structure 30A, the amount of strain applied to the oxide superconducting wires 4, 5, and 6 when they are bent can be reduced. As a result, it is possible to suppress the stress concentration on the oxide superconducting layer 12 on both sides of the conductive bonding materials 22B and 22C, thereby suppressing the deterioration of the superconducting characteristics. Further, in the connection structure 33A, the non-bonding regions 62A ₁ and 62A ₂ are provided on both sides of the conductive bonding material 22B, and the non-bonding regions 72A ₁ and 72A ₂ are provided on both sides of the conductive bonding material 22C. As in the structure of the second embodiment described above based on FIG. 4, stress concentration on the oxide superconducting layer 12 can be suppressed, and deterioration of superconducting characteristics can be suppressed.

FIG. 11 shows a conductive bonding material, a bonding region, and a non-bonding region provided in a connection structure according to a fifth modification of the second embodiment of the present invention. In this example, the structure is the same as that of the previous example. In addition to the conductive bonding materials 22B and 22C, auxiliary bonding regions 22e made of dotted conductive bonding materials are provided at the corners of the non-bonding regions 62A ₂ and 72A _{2 that} are triangular in plan view.
If the auxiliary junction region 22e is provided as shown in FIG. 11, when the oxide superconducting wires 4, 5, 6 are bent in an inverted U shape so that the oxide superconducting wire 6 is on top, the oxide superconducting Both end portions 6a and 6b of the wire 6 are deformed along the curvature of the oxide superconducting wires 4 and 5 located below them. Therefore, even if the oxide superconducting wires 4, 5, 6 are curved as described above, both ends 6 a, 6 b and the surfaces of the oxide superconducting wires 4, 5 facing each other (the surface of the second stabilization layer 14). ) Does not widen.

  This is because the distal end side of the oblique side portion 22a is positioned on one side of the outer end portion of the rectangular region K4, and the auxiliary junction region 22e is provided on the other end side of the outer side of the rectangular region K4. This is because the end 6 a of 6 can be deformed following the oxide superconducting wire 4. In addition, the distal end side of the oblique side portion 22b is positioned on one side of the outer end of the rectangular region K5, and the auxiliary bonding region 22e made of a conductive bonding material is provided on the other end of the outer side of the rectangular region K5. The influence of tensile stress on the end 6b of the oxide superconducting wire 6 along the oxide superconducting wire 5 is small.

It should be noted that the oxide superconducting wire is obtained by positioning the distal end side of the oblique side 22a on one side of the outer end of the rectangular region K4 and positioning the distal end side of the oblique side 22b on the other end of the outer side of the rectangular region K5. 6 can be deformed so as to follow the curvature of the oxide superconducting wires 4 and 5 to some extent, and a certain effect can be obtained that the gap between the ends 6a and 6b and the second stabilization layer 14 does not widen. . However, in addition to them, by providing the point-like auxiliary junction region 22e, both ends of the oxide superconducting wire 6 can be faithfully followed and deformed with respect to the oxide superconducting wires 4 and 5. As a result, the oxide superconducting wire Even if 4, 5, and 6 are curved, it is possible to more effectively prevent the phenomenon that the gaps formed at both ends of the oxide superconducting wire 6 are widened.
If the gap formed at both ends of the connecting oxide superconducting wire 6 seems to widen, when the oxide superconducting wires 4, 5, 6 are bent, peeled portions are formed at both ends of the oxide superconducting wire 6. Appearance of appearance that seems to have occurred. By adopting the above-described structure, it is possible to provide a structure in which the gaps at both ends of the oxide superconducting wire 6 are not widened even if the oxide superconducting wires 4, 5, 6 are curved.

FIG. 12 shows a conductive bonding material, a bonding region, and a non-bonding region provided in a connection structure according to a sixth modification of the second embodiment of the present invention. In this example, the conductive bonding of the previous example is shown. In this structure, rectangular conductive bonding materials 22D and 22E made of the same material as the materials 22B and 22C are provided in the first and second overlapping portions 60A and 70A. Unbonded area 62A ₁ and the non-bonding region 62A ₃ so as to sandwich the conductive bonding material 22D is provided. Rectangular auxiliary junction area 22f is formed in the rectangular region K4 outside the non-bonding region 62A _3, rectangular auxiliary junction region 22f is formed on the outside of the non-bonding region 72A ₃ in the rectangular region K5.
In the structure shown in FIG. 12, since the non-bonding region 62A ₃ so as to sandwich the conductive bonding material 22D unbonded region 62A ₁ is provided, the bonding of the second embodiment described above on the basis of FIG. 2 structure The same effects as the body 30 are exhibited. Moreover, since the non-bonding region 72A ₁ and the non-bonding region 72A ₃ so as to sandwich the conductive bonding material 22E is provided, the equivalent joint structure 30 of the second embodiment described above on the basis of FIG. 2 Has an effect.
In addition, since the auxiliary junction region 22f is formed at positions corresponding to both end portions of the oxide superconducting wire 6, when the joining portion of the oxide superconducting wires 4, 5, 6 is curved, the oxide superconducting wire 6 The effect that the gaps at both ends do not widen can be obtained as in the case of the fifth modification.

FIG. 13 shows a conductive bonding material, a bonding region, and a non-bonding region provided in a connection structure according to a seventh modification of the second embodiment of the present invention. In this example, the conductive bonding of the previous example is shown. In this structure, rectangular conductive bonding materials 22F and 22G made of the same material as the materials 22B and 22C are provided in the first and second overlapping portions 60A and 70A. Unbonded area 62A ₁ and the non-bonding region 62A ₃ so as to sandwich the conductive bonding material 22F is provided. In the rectangular region K4, (2 one in the width direction of the rectangular region K4 in the example of FIG. 13) punctate auxiliary junction region 22g at a portion of from the outside of the non-bonding region 62A ₃ multiple is formed. In the rectangular region K5, (2 one in the width direction of the rectangular region K5 in the example of FIG. 13) punctate auxiliary junction region 22g at a portion of from the outside of the non-bonding region 72A ₃ multiple is formed.

In the structure shown in FIG. 13, since the non-bonding region 62A ₃ so as to sandwich the conductive bonding material 22F unbonded region 62A ₁ is provided, the bonding of the second embodiment described above on the basis of FIG. 2 structure The same effects as the body 30 are exhibited. Moreover, since the non-bonding region 72A ₁ and the non-bonding region 72A ₃ so as to sandwich the conductive bonding material 22G is provided, comparable to the joined structure 30 of the second embodiment described above on the basis of FIG. 2 Has an effect.
Further, as in the previous modification, both ends of the oxide superconducting wire 6 can be deformed so as to follow the curvature of the oxide superconducting wires 4 and 5, and a structure in which a gap is hardly generated at both ends of the oxide superconducting wire 6 is obtained. be able to.

FIG. 14 shows a conductive bonding material provided in a connection structure according to an eighth modification of the second embodiment of the present invention. In this example, the same material as the conductive bonding materials 22B and 22C of the previous example is shown. This is a structure in which rectangular conductive bonding materials 22H and 22I made of are provided in the first and second overlapping portions 60A and 70A. Unbonded area 62A ₁ and the non-bonding region 62A ₂ so as to sandwich the conductive bonding material 22H are provided. In the rectangular region K4, partially in dots auxiliary joining region 22g than the outer unbonded region 62A ₁ is formed with a plurality punctate auxiliary bonding region 22e is formed at a portion of from the corner portion of the non-bonding region 62A ₂ ing. In the rectangular region K5, partially in dots auxiliary joining region 22g than the outer unbonded region 72A ₁ is formed with a plurality punctate auxiliary bonding region 22e is formed at a portion of from the corner portion of the non-bonding region 72A ₂ ing.

In the structure shown in FIG. 14, since to sandwich the conductive bonding material 22H and the non-bonding region 62A ₂ unbonded region 62A ₁ is provided, the bonding of the second embodiment described above on the basis of FIG. 2 structure The same effects as the body 30 are exhibited. Moreover, since the non-bonding region 72A ₁ and the non-bonding region 72A ₂ so as to sandwich the conductive bonding material 22I is provided, comparable to the joined structure 30 of the second embodiment described above on the basis of FIG. 2 Has an effect.
Moreover, since both ends of the oxide superconducting wire 6 can be deformed so as to follow the curvature of the oxide superconducting wires 4 and 5 as in the previous modification, the gap on both ends of the oxide superconducting wire 6 cannot be widened. The same effects as those of the modified example are achieved.

FIG. 15 shows a conductive bonding material, a bonding region, and a non-bonding region provided in a connection structure according to a ninth modification of the second embodiment of the present invention. In this example, the conductive bonding of the previous example is shown. In this structure, conductive bonding materials 22J and 22K made of the same material as the materials 22B and 22C are provided in the first and second overlapping portions 60A and 70A.
In the structure shown in FIG. 15, the non-bonding region 62A ₄ triangular is formed on one of the corners than the outer rectangular region K4, triangular non-bonding region 72A at one corner than the outer rectangle K5 ₄ is formed. That is, the oblique side portion 22a is formed at the outer corner portion of the conductive bonding material 22J in the bonding region 61C, and the oblique side portion 22f is formed at the outer corner portion of the conductive bonding material 22K in the bonding region 71C. In this modified example, the oblique side portion 22a and the oblique side portion 22f are not arranged in parallel, but non-joining regions 62A ₄ and 72A ₄ are formed on both sides of the conductive joining materials 22J and 22K.

In the structure shown in FIG. 15, the non-bonding region 62A ₄ is provided outside of the conductive bonding material 22J, because the non-bonding region 72A ₄ is provided outside of the conductive bonding material 22K, previously based on Figure 2 There exists an effect equivalent to the joining structure 30 of 2nd Embodiment demonstrated in (2). Moreover, since it has a non-bonding region 62A _4, 72A ₄ triangular, it can be obtained preceding figures 9, the same effects as the modification shown in FIG. 10.

The shape of the non-bonded region provided on both sides of the conductive bonding material is not limited to the above-described structure, and a triangular shape having a bottom corresponding to the entire width of the rectangular region K4 as in the tenth modification shown in FIG. unbonded area 62A ₅ are formed, it may be employed a structure in which non-bonding region 72A ₅ similar triangular in rectangular region K5 are formed.
In the example shown in FIG. 16, a V-shaped oblique side portion 22h is formed on the end portion side of the conductive bonding material 22L in the bonding region 61D, and a V-shaped shape is formed on the end portion side of the conductive bonding material 22M in the bonding region 71D. In this example, the oblique side portion 22h is formed.
Also with this structure, the same effects as those of the modified examples shown in FIGS. 9 and 10 can be obtained.

Also, as in the modification of the 11 shown in FIG. 17, the structure unbonded regions 62A ₆ of triangular which are two forms with a base corresponding to half the width of the rectangular region K4, the rectangular region K5 equivalent unbonded area 72A ₆ triangular may be employed two formed structure.
In the eleventh modification shown in FIG. 17, the oblique side portion 22i having a triangular protrusion shape in plan view is formed on the outer end portion of the conductive bonding material 22N in the bonding region 61E, and the outer edge portion of the conductive bonding material 22P in the bonding region 71E. This is an example in which a hypotenuse 22i having a triangular projection shape in plan view is formed.
Also in the modified example shown in FIG. 17, the same effects as the modified examples shown in FIGS. 9 and 10 can be obtained.
As described above, the shape of the hypotenuse formed at the boundary between the joining region and the non-joining region can be variously changed, and the shape of the non-joining region can be variously changed even in the structure in which the hypotenuse is not provided. Of course.

(Superconducting cable)
The oxide superconducting wire 1 (that is, the oxide superconducting wire 2, 3, 4, 5) connected by the connection structure 30, 31, 32, 33, 34, 35, 36 manufactured as described above is shown in FIG. 18 can be used as a superconducting cable 80 shown in FIG. A cable core 85 at the center of the superconducting cable 80 is formed by winding a plurality of tape-shaped oxide superconducting wires 1 around a metal (for example, copper) former 81 in a spiral manner over two layers with an insulating layer 82 interposed therebetween. And is covered with a conductive cable stabilization layer 83. The cable core 85 is accommodated in a metal double insulation tube 84 having flexibility. The double heat insulating tube 84 has an inner tube 84a and an outer tube 84c, and a vacuum heat insulating layer 84b is formed between the inner tube 84a and the outer tube 84c to eliminate the influence of heat from the outside. It has become.
By using the oxide superconducting wire 1 connected to the superconducting cable 80 as described above, the superconducting cable 80 having various lengths can be produced regardless of the size of the production line.
Further, when connecting a plurality of superconducting cables 80, the connection structure 30, 31, 32, 33, 34, 35, 36 can be adopted at the connecting portion to connect the oxide superconducting wire 1. .

(Superconducting fault current limiter)
In addition, the superconducting fault current limiter shown in FIG. 19 as an example using the oxide superconducting wire 1 connected by the connection structure 30, 31, 32, 33, 34, 35, 36 of the first or second embodiment described above. 99 can be made.
In the superconducting fault current limiter 99, the oxide superconducting wire 1 connected by the connection structures 30, 31, 32, 33, 34, 35, 36 is wound around the winding drum in a plurality of layers, and the superconducting current limiting module. 90 and is stored in a liquid nitrogen container 95 filled with liquid nitrogen 98 as the superconducting current limiting module 90. Further, the liquid nitrogen container 95 is stored inside a vacuum container 96 that blocks heat from the outside.
The liquid nitrogen container 95 has a liquid nitrogen filling part 91 and a refrigerator 93 in the upper part, and a heat anchor 92 and a hot plate 97 are provided below the refrigerator 93.
The superconducting current limiter 99 has a current lead portion 94 for connecting an external power source (not shown) to the superconducting current limiter module 90.
When used as the superconducting fault current limiter module 90 of the superconducting fault current limiter 99 as described above, the oxide superconducting wire 1 has Ni—Cr as the second stabilizing layer 14 as described with reference to FIG. Use a high-resistance metal such as

(Superconducting motor)
20A and 20B, an example of a superconducting motor 130 configured using the oxide superconducting wire 1 connected by the connection structures 30, 31, 32, 33, 34, 35, and 36 described above. Show. The superconducting motor 130 includes a cylindrical rotor 132 that is rotatably supported in a cylindrical sealed container 131.

A plurality of superconducting motor coils 135 are attached around the central portion of the rotary shaft 133 around the shaft, and a plurality of copper coils made of copper coils supported on the inner wall side of the container 131 around the plurality of superconducting motor coils 135. The normal conducting coil 136 is arranged.
The superconducting motor coil 135 is formed by winding the oxide superconducting wire 1 connected by the connection structures 30, 31, 32, 33, 34, 35, 36 around a rectangular bobbin having an appropriate sumi R. ing.
The rotating shaft 133 is provided with a plurality of pipes for allowing the cooling gas to flow in or out, and the cooling gas is introduced into the container 131 from a refrigerant supply device (not shown) separately provided outside to cool the cooling gas. The superconducting motor coil 135 can be cooled to a critical temperature or lower by gas. The superconducting motor coil 135 is cooled below the critical temperature, while the normal conducting coil 136 is configured as a normal temperature part.

  The superconducting motor 130 shown in FIGS. 20A and 20B introduces a cooling gas into the container 131 and uses the cooling gas to cool the superconducting motor coil 135 to a critical temperature or lower. A necessary current is supplied to the normal conducting coil 136 from a power supply (not shown) separately, and a necessary current is supplied to the superconducting motor coil 135 from a power supply (not shown) separately, resulting in a magnetic field generated by both coils. The rotating shaft 133 can be rotated by the rotational force thus used, and can be used as the superconducting motor 130.

(Superconducting coil)
The superconducting coil 101 shown in FIG. 21B is configured by winding the oxide superconducting wire 1 connected by the connection structures 30, 31, 32, 33, 34, 35, and 36 manufactured as described above. be able to. In addition, a plurality of superconducting coils 101 are stacked, and the superconducting coils 101 are connected to each other by the connection structures 30, 31, 32, 33, 34, 35, and 36, so that the strong magnetic force shown in FIG. Can be formed.

As described above, the oxide superconducting wire 1 connected by the connection structures 30, 31, 32, 33, 34, 35, and 36 described above can be used for various superconducting devices.
Here, the superconducting device is not particularly limited as long as it has the oxide superconducting wire 1, and examples thereof include a superconducting cable, a superconducting motor, a superconducting transformer, a superconducting current limiter, and a superconducting power storage device.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.
(Sample preparation)
An Al ₂ O ₃ (diffusion prevention layer; film thickness 150 nm) film was formed by sputtering on a tape-shaped Hastelloy (trade name, manufactured by Haynes, USA) having a width of 5 mm and a thickness of 0.1 mm. On top, Y ₂ O ₃ (bed layer; film thickness 20 nm) was formed by ion beam sputtering. Next, MgO (metal oxide layer; film thickness: 10 nm) is formed on the bed layer by ion beam assisted vapor deposition (IBAD method), and 0.5 μm thick is formed thereon by pulse laser vapor deposition (PLD method). CeO ₂ (cap layer) was formed. Next, a 2.0 μm-thick GdBa ₂ Cu ₃ O _7-δ (oxide superconducting layer) is formed on the CeO ₂ layer by the PLD method, and further a 10 μm-thick Ag layer (first film) is formed on the oxide superconducting layer by the sputtering method. In addition, a 0.1 mm thick Cu tape is formed on the Ag layer so as to form a C-shaped cross section, and a laminate (base material, intermediate layer, oxide superconducting layer) is formed. The peripheral surface of the first stabilization layer laminate) was covered and deposited with solder. Thus, a plurality of oxide superconducting wires 1 shown in FIG. 1 were produced. This oxide superconducting wire 1 is commonly used in the following examples and comparative examples.

Example 1
Using the above-described oxide superconducting wire, Example 1 having the connection structure 33 (see FIGS. 4A and 4B) of the second embodiment was produced. The first and second oxide superconducting wires 4 and 5 having a length of 500 m and the third oxide superconducting wire 6 having a length of 65 mm, which are the oxide superconducting wires described above, were used. In FIGS. 4A and 4B, the distance e between the end portions 4a and 5b of the first and second oxide superconducting wires 4 and 5 is set to 5 mm. Further, the lengths H ₆₁ and H ₇₁ of the joining regions ₆₁ and ₇₁ were 20 mm, and the lengths H ₆₂ and H ₇₂ of the non-joining regions ₆₂ and ₇₂ were 1 mm.
Furthermore, in the manufacturing procedure of Example 1 described above, Comparative Example 1 having a structure in which the entire overlapping portions 60 and 70 (20 mm in length) are bonded by the conductive bonding material 22 was manufactured.
In Example 1 and Comparative Example 1, In solder was used as the conductive bonding material 22.

The connection structure of Example 1 and Comparative Example 1 was subjected to a bending test. In the bending test, the connecting structure of each sample is bent along the stacking direction so that the first and second oxide superconducting wires 4 and 5 are inside and the third oxide superconducting wire 6 is outside. Bending was performed only once at 30 mm, and the ratio (deterioration rate) of critical current before and after that was measured. The results are shown in FIG.
Referring to FIG. 22, in Example 1, the critical current hardly deteriorates, whereas in Comparative Example 1, the deterioration rate is greatly deteriorated to about 0.92.
Thereby, it was confirmed that the deterioration due to bending is suppressed by providing a non-joining region of 1 mm from the end in the overlapping portion.

(Example 2)
In the manufacturing procedure of the first embodiment described above, the second embodiment in which the lengths H ₆₂ and H ₇₂ of the non-joining regions ₆₂ and ₇₂ are 5 mm and the lengths H ₆₁ and H ₇₁ of the joining regions ₆₁ and ₇₁ are 20 mm is manufactured. did.
In addition, in the manufacturing procedure of Example 1 described above, Comparative Example 2 having a structure in which the entire overlapping portions 60 and 70 (20 mm in length) are bonded by the conductive bonding material 22 was manufactured.
In Example 2 and Comparative Example 2, In solder was used as the conductive bonding material 22.

The connection structure of Example 2 and Comparative Example 2 was subjected to a bending test. The bending test is performed in a predetermined manner so that the first and second oxide superconducting wires 4 and 5 are inside and the third oxide superconducting wire 6 is outside along the stacking direction. After bending once at the bending radius, the first and second oxide superconducting wires 4 and 5 are on the outside and the third oxide superconducting wire 6 is on the inside along the stacking direction, and 1 with the same bending radius. The ratio (deterioration rate) of critical current before and after the turn bending was measured. FIG. 23 shows the relationship between the bending radius and the deterioration rate in Example 2 and Comparative Example 2.
Referring to FIG. 23, in Example 1, the critical current is significantly deteriorated at a bending radius of 20 to 30 mm, whereas in Comparative Example 1, the deterioration is already remarkable at a bending radius of 50 mm.
Thereby, it was confirmed that deterioration due to bending is suppressed by providing a non-bonded region 5 mm from the end in the overlapped portion. Further, it was confirmed that the connection structure of Example 1 hardly caused any deterioration if the bending was 30 mm or more.

(Example 3)
Example 3 having the connection structure 35 (see FIG. 5B) in which the non-joining regions 62 and 72 are provided only in the vicinity of both ends of the third oxide superconducting wire 6 in the manufacturing procedure of Example 1 described above. Was made. Note that the lengths H ₆₂ and H ₇₂ of the non-joining regions ₆₂ and ₇₂ were 5 mm, and the lengths H ₆₁ and H ₇₁ of the joining regions ₆₁ and ₇₁ were 20 mm.
In addition, in the manufacturing procedure of Example 3 described above, Comparative Example 3 having a structure in which the entire overlapping portions 60 and 70 (length 20 m) are bonded by the conductive bonding material 22 was manufactured.
In Example 3 and Comparative Example 3, Sn solder was used as the conductive bonding material 22.

The connection structure of Example 3 and Comparative Example 3 was subjected to a bending test. In the bending test, the connection structure of each sample is variously arranged so that the first and second oxide superconducting wires 4 and 5 are inside and the third oxide superconducting wire 6 is outside along the stacking direction. Bending was performed only once at the bending radius, and the ratio (deterioration rate) of critical current before and after that was measured. FIG. 24 shows the relationship between the bending radius and the deterioration rate in Example 3 and Comparative Example 3.
Referring to FIG. 23, Example 1 gradually deteriorates as the bending radius is reduced, but the deterioration rate is about 0.97 even at a bending radius of 40 mm. In contrast, in Comparative Example 1, the deterioration rate is already about 0.97 at a bending radius of 80 mm.
Thereby, the non-joining regions 62 and 72 are formed only in one of the end portions of the overlapping portions 60 and 70 as in the connection structure 35 (see FIG. 5B) of the modification of the second embodiment. It was confirmed that the deterioration due to bending can be suppressed even in the case of doing so.

  From the results of Examples 1 to 3, the superiority of the connection structure and the connection method according to the present invention was confirmed.

Example 4
Using the above-described oxide superconducting wire, Example 4 having the connection structure 33A (see FIGS. 9 and 10) of the fourth modification of the second embodiment was produced. The first and second oxide superconducting wires 4 and 5 having a length of 500 m and the third oxide superconducting wire 6 having a length of 65 mm, which are the oxide superconducting wires described above, were used. 9 and 10, the distance e between the end portions 4a and 5a of the first and second oxide superconducting wires 4 and 5 is set to 5 mm. Further, the maximum length of the joining regions 61A and 71A was 20 mm, and the minimum length of the non-joining regions 62A ₁ and 72A ₁ was 1 mm. The slope of the hypotenuse part formed on the conductive bonding material is the slope taking the value a shown in FIG. The a value shown in FIG. 10 indicates the maximum length that the hypotenuse 22a formed in the conductive bonding material 22B occupies in the longitudinal direction of the oxide superconducting wire.
Further, Comparative Example 1 having a structure in which the overlapping portions 60 </ b> A and 70 </ b> A (length: 10 mm) are joined by the conductive joining material 22 in the same production procedure as in Example 1 described above was produced.
In Example 4 and Comparative Example 4, In solder was used as the conductive bonding material 22.

  The connection structure of Example 4 and Comparative Example 4 was subjected to a bending test. In the bending test, the connecting structure of each sample is bent along the stacking direction so that the first and second oxide superconducting wires 4 and 5 are inside and the third oxide superconducting wire 6 is outside. Bending operation that is bent once at 50 mm, and then bent once at a bending radius of 50 mm so that the first and second oxide superconducting wires 4 and 5 are on the outer side and the third oxide superconducting wire 6 is on the inner side on the opposite side. As a reciprocating bending operation, the reciprocating bending operation was repeated three times, a three reciprocating bending test was performed, and the ratio (deterioration rate) of critical current before and after that was measured. The results are shown in Table 1 below.

In Table 1, an a value of 0 indicates that there is no oblique side and the end side of the conductive bonding material has a shape that is orthogonal to the length direction of the oxide superconducting wire.
From the results shown in Table 1, when a triangular non-bonded region is formed at the end of the conductive bonding material, no decrease in the Ic value is observed even when three reciprocating bendings act. On the other hand, when the end side of the conductive bonding material is orthogonal to the length direction of the oxide superconducting wire and no non-bonded region is formed on the end side of the conductive bonding material, the Ic value is obtained by three repetitive bendings. Decrease was observed.
Further, for the sample in which the a value was set to 5 mm, a 10 reciprocating bending test was tried, but no decrease in Ic value was observed after the 10 reciprocating bending test.
Next, instead of the conductive bonding material shown in FIG. 10, the shape of the conductive bonding material with the auxiliary bonding region shown in FIG. 11 was adopted, and an equivalent test was performed. That is, a 10-round repetitive bending test was tried on a sample with the a value set to 5 mm and a point-shaped auxiliary joining region (diameter: 2 mm) provided, but a decrease in the Ic value after the 10-way repetitive bending test was observed. I couldn't. In addition, about the auxiliary joining area | region, although the sample of diameter 1mm was also created and tested, the effect equivalent to the auxiliary joining area | region of diameter 2mm was acquired.
From the above results, the effect of providing the oblique side portion in the conductive bonding material and the effect of providing the auxiliary bonding region were confirmed.

DESCRIPTION OF SYMBOLS 1 ... Oxide superconducting wire, 1a, 2a, 3a, 4a, 5a ... edge part, 2, 4 ... 1st oxide superconducting wire, 3, 5 ... 2nd oxide superconducting wire, 6 ... 3rd oxidation Superconducting wire, 6a ... first end, 6b ... second end, 11 ... intermediate layer, 12 ... oxide superconducting layer, 13 ... first stabilizing layer, 14 ... second stabilizing layer, 15 ... Laminate, 16 ... solder layer, 22 ... conductive bonding material, 22A, 22B, 22C, 22D, 22E, 22F, 22G, 22H, 22I, 22J, 22K, 22L, 22M, 22N, 22P ... conductive bonding material, 22a, 22b, 22f, 22g, 22i ... hypotenuse, 22e, 22f, 22g ... auxiliary joint region, 30, 31, 32, 33, 34, 35, 36 ... connection structure, 30A, 33A ... connection structure, 50 ... Overlapping part, 51, 61, 71 ... Joining region, 51A 61A, 61B, 61C, 61D, 61E, 71A, 71C, 71D, 71E ... junction region, 52, 62, 72 ... non-bonding _{region, 52A 1, 52A 2, 62A} 1, 62A 2, 72A 1, 72A 2 ... non Joining region 53, 63, 73 ... overflow portion, 60 ... first overlapping portion, 70 ... second overlapping portion, 80 ... superconducting cable, 99 ... superconducting current limiter, 100 ... superconducting coil laminate, 101 ... superconducting coil, 130 ... superconducting motor, 135 ... superconducting motor coil, 136 ... normal conducting _{coil, L, H 50, H 51} , H 52, H 60, H 61, H 62, H 70, H 71, H 72 ... length, e ... distance, _H51A , _H52A , _H60A , _H61A , _H62A , _H70A , _H71A , _H72A ... length.

Claims (14)

A connection structure in which a pair of oxide superconducting wires are formed by laminating an intermediate layer, an oxide superconducting layer, and a stabilizing layer on a tape-shaped substrate,
The stabilizing layers in the vicinity of the ends of the pair of oxide superconducting wires are arranged to face each other to form an overlapping portion,
A joining region joined by a conductive joining material is formed on at least a part of the overlapping portion,
An oxide superconducting wire characterized in that a non-joined region that is not joined by a conductive joining material having a longitudinal length of 1 mm or more and 100 mm or less is formed on at least one of longitudinal ends in the overlapped portion. Connection structure.   2. The oxide superconductivity according to claim 1, wherein the length of one non-joining region is longer than the length of the other non-joining region in the length of a pair of non-joining regions located on both sides of the overlapping portion. Wire connection structure. A first oxide superconducting wire that is the three oxide superconducting wires, a second oxide superconducting wire, and a third oxide superconducting wire;
The first and second oxide superconducting wires are arranged adjacent to each other with a predetermined gap between the ends to be connected, with the side on which the oxide superconducting layer is formed aligned with the base material,
The stabilization layer of the third oxide superconducting wire is bridged to the stabilization layer of the first and second oxide superconducting wires so as to straddle the adjacent ends, and the first and second overlapping layers are bridged. Forming part,
A bonding region bonded with a conductive bonding material is formed on at least a part of the first overlapping portion, and at least one of the longitudinal end portions in the first overlapping portion has a longitudinal length. A non-joining region that is not joined by a conductive joining material of 1 mm or more and 100 mm or less is formed,
A bonding region bonded with a conductive bonding material is formed on at least a part of the second overlapping portion, and at least one of the longitudinal ends in the second overlapping portion has a longitudinal length. 3. The oxide superconducting wire connecting structure according to claim 1, wherein a non-bonded region is formed by a conductive bonding material of 1 mm or more and 100 mm or less.   Of the non-joining regions formed at the longitudinal ends in the first and second overlapping portions, the longitudinal length of the non-joining region formed on the end side of the third oxide superconducting wire 4 is longer than a length in a longitudinal direction of a non-joining region formed on an end side of the first or second oxide superconducting wire. Connection structure of oxide superconducting wire.   5. The oxide superconductivity according to claim 1, wherein two or more joining regions are formed in the overlapping portion, and the joining regions are separated by a non-joining region. Wire connection structure.   The end surfaces of the end portions of the first and second oxide superconducting wires on the side close to the joining region are orthogonal to the longitudinal direction of the oxide superconducting wires, and the oxidation occurs at the boundary between the joining region and the non-joining region. The connecting structure according to any one of claims 1 to 5, wherein an oblique side portion that is inclined in plan view with respect to a longitudinal direction of the superconductor wire is formed.   The connection structure according to claim 1, wherein an auxiliary joining region narrower than the non-joining region is formed in the non-joining region on the side opposite to the joining region side.   A superconducting apparatus comprising the oxide superconducting wire connection structure according to any one of claims 1 to 7. Forming a first and a second oxide superconducting wire formed by laminating an intermediate layer, an oxide superconducting layer and a stabilizing layer on a tape-shaped substrate;
A stabilization layer surface of the first oxide superconducting wire or the second oxide superconducting wire, in the vicinity of the end portions of the first oxide superconducting wire and the second oxide superconducting wire. 1 mm or more and 100 mm at positions corresponding to the end portions of the first oxide superconducting wire and the end portions of the second oxide superconducting wire in the portions where the wires are covering each other when the stabilizing layers are opposed to each other. A step of arranging a masking material with the following width;
Arranging a conductive bonding material in a space formed between the masking materials;
Bonding the first oxide superconducting wire and the second oxide superconducting wire;
And a step of removing the masking material. A method of manufacturing a connection structure of oxide superconducting wire. Forming a first, second and third oxide superconducting wire by laminating an intermediate layer, an oxide superconducting layer and a stabilizing layer on a tape-shaped substrate;
Aligning the side on which the oxide superconducting layer is formed with respect to the base material of the first and second oxide superconducting wires, and arranging adjacent ends with a predetermined gap between them;
By bridging the stabilization layer of the third oxide superconductor to the stabilization layer of the first and second oxide superconducting wires so as to straddle the adjacent ends,
When the stabilization layers in the vicinity of the end portions of the first and third oxide superconducting wires are opposed to each other, the end portions of the first oxide superconducting wire and the third portion are covered with each other. A step of arranging a masking material with a width of 1 mm or more and 100 mm or less at a position corresponding to the end portion of the oxide superconducting wire;
When the stabilizing layers in the vicinity of the end portions of the second and third oxide superconducting wires are opposed to each other, the end portions of the second oxide superconducting wire and the third portion are covered with each other. A step of arranging a masking material with a width of 1 mm or more and 100 mm or less at a position corresponding to the end portion of the oxide superconducting wire;
Arranging a conductive bonding material in a space formed between the masking materials;
Joining the first oxide superconducting wire and the third oxide superconducting wire, joining the second oxide superconducting wire and the third oxide superconducting wire;
The method for manufacturing a connection structure for an oxide superconducting wire according to claim 9, further comprising a step of removing the masking material. When the first and third oxide superconducting wires and the stabilizing layers in the vicinity of the end portions of the second and third oxide superconducting wires are opposed to each other, in the portion where the wires cover each other,
The width of the masking material disposed on the end side of the third oxide superconducting wire is longer than the width of the masking disposed on the end side of the first or second oxide superconducting wire. The manufacturing method of the connection structure of the oxide superconducting wire of Claim 10 characterized by these.   The superposed wire connecting structure according to any one of claims 9 to 11, wherein the overlapping portion is masked, and both sides thereof are bonded by the conductive bonding material to form a bonding region. Body manufacturing method.   As the oxide superconducting wire, an oxide superconducting wire whose end surface near the joining region is orthogonal to the longitudinal direction of the oxide superconducting wire is used, and the boundary between the joining region and the non-joining region is used. The connection structure of the oxide superconducting wire according to any one of claims 9 to 12, wherein a joining region having a hypotenuse inclined in plan view with respect to a longitudinal direction of the oxide superconducting wire is formed. Manufacturing method.   The method for manufacturing a connection structure according to any one of claims 9 to 13, wherein an auxiliary joining region narrower than the non-joining region is formed on a side opposite to the joining region side in the non-joining region. .

Images