Oxide superconducting wire, superconducting coil, and method for manufacturing oxide superconducting wire

Abstract

To provide an oxide superconducting wire capable of reducing a compressive force applied on an oxide superconducting layer during operation of the superconducting coil to suppress deterioration of characteristics.SOLUTION: An oxide superconducting wire includes a tape-shaped superconducting laminate including a substrate having a first surface and a second surface opposite to the first surface, and an oxide superconducting layer having a third surface facing the second surface of the substrate and a fourth surface opposite to the third surface; a first portion facing the first surface of the substrate; a second portion facing the fourth surface of the oxide superconducting layer; a third portion connecting the first portion and the second portion; a stabilizing layer covering the superconducting laminate; and a metal tape, wherein a widthwise dimension of the metal tape is greater than the widthwise dimension of the stabilizing layer, and the metal tape is connected to only one of the first portion and the second portion of the stabilizing layer.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an oxide superconducting wire, a superconducting coil, and a method for manufacturing an oxide superconducting wire.

Background Art

[0002] Patent Document 1 discloses an oxide superconducting wire including a superconducting laminate including a substrate and an oxide superconducting layer, a stabilizing layer covering the superconducting laminate, and a metal tape reinforcing the superconducting laminate and the stabilizing layer. Further, Patent Document 2 discloses a superconducting coil in which a plurality of pancake coils formed by winding an oxide superconducting wire are prepared and laminated in the longitudinal direction of the winding cylinder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, during the operation of a superconducting coil as in Patent Document 2, it is known that a force (compressive force) that compresses in the stacking direction of the pancake coil acts due to the interaction between the current flowing through the oxide superconducting wire and the generated magnetic field. At this time, in the oxide superconducting wire constituting the pancake coil, there is a problem that the oxide superconducting layer at the widthwise end of the oxide superconducting wire deteriorates due to the compressive force from the adjacent pancake coils in the stacking direction, and the characteristics of the oxide superconducting wire deteriorate.

[0005] The present invention has been made in consideration of such circumstances, and an object thereof is to provide an oxide superconducting wire capable of reducing the compressive force applied to the oxide superconducting layer during the operation of a superconducting coil and suppressing a decrease in characteristics.

Means for Solving the Problem

[0006] To solve the above problems, an oxide superconducting wire according to one aspect of the present invention includes a substrate having a first surface and a second surface opposite to the first surface, and an oxide superconducting layer having a third surface facing the second surface of the substrate and a fourth surface opposite to the third surface. A tape-shaped superconducting laminate including the oxide superconducting layer, a first portion facing the first surface of the substrate, a second portion facing the fourth surface of the oxide superconducting layer, and a third portion connecting the first portion and the second portion. A stabilizing layer covering the superconducting laminate, and a metal tape. The dimension of the metal tape in the width direction is larger than the dimension of the stabilizing layer in the width direction, and the metal tape is joined only to one of the first portion and the second portion of the stabilizing layer.

[0007] According to the above aspect of the present invention, since the width of the metal tape is larger than the width of the stabilizing layer, the compressive force from adjacent pancake coils is applied to the metal tape and does not reach the superconducting laminate and the stabilizing layer which are narrower than the metal tape. Therefore, during the operation of the superconducting coil, the widthwise ends of the oxide superconducting layer are less likely to deteriorate, and a decrease in the characteristics of the oxide superconducting wire can be suppressed.

[0008] Here, the metal tape may be connected to the second portion of the stabilizing layer.

[0009] In this case, for example, compared with the case where the metal tape is joined to the first portion of the stabilizing layer, the oxide superconducting layer approaches the neutral plane in the thickness direction of the oxide superconducting wire. For this reason, the stress applied to the oxide superconducting layer when the oxide superconducting wire is bent is reduced.

[0010] Further, the metal tape may have a recess in which at least a part of the stabilizing layer is accommodated.

[0011] In this case, the compressive force applied to the oxide superconducting layer via the metal tape can be reduced.

[0012] Also, in the superconducting coil according to one aspect of the present invention, any of the above oxide superconducting wire materials may be wound.

[0013] In this case, for example, compared with a superconducting coil using an oxide superconducting wire material in which the width of the metal tape is equal to the width of the stabilization layer, the compressive force applied to the oxide superconducting layer during operation of the superconducting coil can be reduced. Therefore, the oxide superconducting layer is less likely to deteriorate, and a decrease in the characteristics of the superconducting coil can be suppressed.

[0014] Also, a method for manufacturing an oxide superconducting wire material according to one aspect of the present invention includes a lamination step of laminating at least one or more layers including an oxide superconducting layer on a tape-shaped substrate to form a superconducting laminate, a stabilization layer forming step of forming a stabilization layer around the superconducting laminate, and a bonding step of bonding a metal tape having a dimension in the width direction larger than the dimension in the width direction of the stabilization layer to only one surface of the stabilization layer.

[0015] In this case, the end portion of the oxide superconducting layer covered with the stabilization layer is less likely to be compressed, and the compressive force applied to the oxide superconducting layer during operation of the superconducting coil can be reduced.

[0016] Also, a method for manufacturing an oxide superconducting wire material according to one aspect of the present invention includes a lamination step of laminating at least one or more layers including an oxide superconducting layer on a tape-shaped substrate to form a superconducting laminate, a cutting step of cutting the superconducting laminate in the longitudinal direction and cutting out a thinned superconducting laminate, a stabilization layer forming step of forming a stabilization layer around the thinned superconducting laminate, and a bonding step of bonding a metal tape having a dimension in the width direction larger than the dimension in the width direction of the stabilization layer to only one surface of the stabilization layer.

[0017] In this case, the end portion of the oxide superconducting layer covered with the stabilization layer is less likely to be compressed, and the compressive force applied to the oxide superconducting layer during operation of the superconducting coil can be reduced.

Advantages of the Invention

[0018] According to the above aspect of the present invention, it is possible to provide a superconducting oxide wire that can reduce the compressive force applied to the oxide superconducting layer during operation of the superconducting coil and suppress the degradation of characteristics.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

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Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0020] (First Embodiment) Hereinafter, a superconducting oxide wire 1, a superconducting coil C, and a method for manufacturing the superconducting oxide wire 1 according to the first embodiment will be described with reference to the drawings. As shown in Fig. 1, the oxide superconducting wire 1 includes a tape-shaped superconducting laminate 10, a stabilizing layer 20 covering the superconducting laminate 10, and a metal tape 30 joined to the stabilizing layer 20. The superconducting laminate 10 includes a substrate 11, an intermediate layer 12, an oxide superconducting layer 13, and a protective layer 14. Each of the substrate 11, the intermediate layer 12, the oxide superconducting layer 13, and the protective layer 14 is formed in a tape shape and laminated in the thickness direction of the superconducting laminate 10. The stabilizing layer 20 covers the outer periphery of the superconducting laminate 10 and serves as a detour path when an excessive current flows through the oxide superconducting layer. The metal tape 30 reinforces the superconducting laminate 10 and the stabilizing layer 20 by being joined to the stabilizing layer 20. Also, by being electrically joined to the stabilizing layer 20, it functions as a detour path for excessive current in the same manner as the stabilizing layer 20.

[0021] (Direction Definition) Here, in the present embodiment, an XYZ orthogonal coordinate system is set to explain the positional relationship of each component. The Z-axis direction is the direction along the longitudinal direction of the superconducting laminate 10. The Y-axis direction is the direction orthogonal to the Z-axis direction and along the thickness direction of the superconducting laminate 10. The Y-axis direction is also the direction in which the layers 11 to 14 of the superconducting laminate 10 are laminated. The X-axis direction is the direction orthogonal to both the Z-axis direction and the Y-axis direction and along the width direction of the superconducting laminate 10. In this specification, the X-axis direction may be referred to as the width direction X, the Y-axis direction may be referred to as the thickness direction Y, and the Z-axis direction may be referred to as the longitudinal direction Z. One direction along the width direction X is referred to as the +X direction or the right direction. The direction opposite to the +X direction is referred to as the -X direction or the left direction. Along the thickness direction Y, the direction from the substrate 11 toward the oxide superconducting layer 13 is referred to as the +Y direction, the upper direction, or the front side. The direction opposite to the +Y direction is referred to as the -Y direction, the lower direction, or the back side. One direction along the longitudinal direction Z is referred to as the +Z direction. The direction opposite to the +Z direction is referred to as the -Z direction.

[0022] Hereinafter, in this specification, the dimension in the width direction X may be simply referred to as the "width". Similarly, the dimension in the thickness direction Y may be simply referred to as the "thickness". The dimension in the longitudinal direction Z may be simply referred to as the "length".

[0023] (Oxide superconducting wire) In the superconducting laminate 10 according to the present embodiment, the substrate 11, the intermediate layer 12, the oxide superconducting layer 13, and the protective layer 14 are laminated in this order in the direction from the bottom to the top. However, the superconducting laminate 10 may not include at least one of the intermediate layer 12 and the protective layer 14. The width of the superconducting laminate 10 is, for example, in the range of 2 to 12 mm. The thickness of the superconducting laminate 10 is, for example, in the range of 10 to 500 μm. The length of the superconducting laminate 10 is, for example, in the range of 1 to 100 m.

[0024] The substrate 11 is a tape-shaped metal substrate. The substrate 11 has a first surface 11a and a second surface 11b opposite to the first surface 11a. Specific examples of the metal constituting the substrate 11 include nickel alloys typified by Hastelloy (registered trademark), stainless steel, and oriented Ni-W alloys in which a structure is introduced into the nickel alloy. In the present embodiment, the substrate 11 has the largest thickness among the layers 11 to 14. The thickness of the substrate 11 is, for example, in the range of 10 to 500 μm.

[0025] The intermediate layer 12 is laminated on the second surface 11b of the substrate 11. The configuration of the intermediate layer 12 is not limited to the example of FIG. 1. For example, the intermediate layer 12 may have a multilayer structure. In this case, the intermediate layer 12 may have a diffusion prevention layer, a bed layer, an orientation layer, a cap layer, etc. in order in the direction from the substrate 11 toward the oxide superconducting layer 13.

[0026] The oxide superconducting layer 13 is laminated on the intermediate layer 12. The oxide superconducting layer 13 has a third surface 13a and a fourth surface 13b opposite to the third surface 13a. The third surface 13a faces the second surface 11b of the substrate 11 in the thickness direction Y. However, in this specification, the term "opposite" includes both cases where there is an intervening substance between two members and cases where there is no intervening substance between two members.

[0027] The oxide superconducting layer 13 is composed of an oxide superconductor. Examples of the oxide superconductor constituting the oxide superconducting layer 13 include RE-Ba-Cu-O based oxide superconductors (REBCO based oxide superconductors) represented by the general formula RE1Ba2Cu3O y (RE123) and the like. Examples of the rare earth element RE include one or more of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. In the general formula of RE123, y is 7 - x (oxygen deficiency amount x: about 0 to 1). The thickness of the oxide superconducting layer 13 is, for example, in the range of 0.5 to 5 μm.

[0028] The protective layer 14 is laminated on the fourth surface 13b of the oxide superconducting layer 13. The protective layer 14 has functions such as bypassing the overcurrent generated during an accident and suppressing the chemical reaction that occurs between the oxide superconducting layer 13 and the layer provided on the protective layer 14. Examples of the material of the protective layer 14 include silver (Ag), copper (Cu), gold (Au), an alloy of gold and silver, other silver alloys, copper alloys, gold alloys, and the like.

[0029] The stabilization layer 20 according to this embodiment is formed in an annular shape in a cross-sectional view perpendicular to the longitudinal direction Z. The stabilization layer 20 has a first portion 21, a second portion 22, and a pair of third portions 23. The first portion 21 extends in the width direction X. The first portion 21 faces the first surface 11a of the substrate 11 in the thickness direction Y. The second portion 22 extends in the width direction X. The second portion 22 faces the fourth surface 13b of the oxide superconducting layer 13 in the thickness direction Y. The pair of third portions 23 extend in the thickness direction Y. The third portion 23 connects both ends in the width direction X of the first portion 21 and both ends in the width direction X of the second portion 22.

[0030] The first portion 21 has a back surface 21a facing downward (the back side). In the present embodiment, the first portion 21 is in contact with the first surface 11a of the substrate 11. The second portion 22 has a front surface 22a facing upward (the front side). In the present embodiment, the second portion 22 is in contact with the upper surface of the protective layer 14. Each third portion 23 has a side surface 23a facing outward in the width direction X. In the present embodiment, each third portion 23 is in contact with the side surfaces of the respective layers 11 to 14 of the superconducting laminate 10. Further, in the present embodiment, the distance in the thickness direction Y between the fourth surface 13b of the oxide superconducting layer 13 and the front surface 22a of the second portion 22 is shorter than the distance in the thickness direction Y between the third surface 13a of the oxide superconducting layer 13 and the back surface 21a of the first portion 21.

[0031] The stabilization layer 20 has a role of diverting (bypassing) an overcurrent generated when the oxide superconducting layer 13 transitions to the normal conducting state. Examples of the stabilizing material constituting the stabilization layer 20 include metals such as copper, copper alloys (e.g., Cu-Zn alloy, Cu-Ni alloy, etc.), aluminum, aluminum alloys, and silver. The thickness of the first portion 21 is within the range of 10 to 500 μm. The same applies to the thickness of the second portion 22 and the width of each third portion 23. The stabilization layer 20 can be formed, for example, by plating (e.g., electroplating). In the present embodiment, the first portion 21, the second portion 22, and the pair of third portions 23 are integrally formed.

[0032] The metal tape 30 has a bonding surface 30a perpendicular to the thickness direction Y and a pair of side surfaces 30b facing outward in the width direction X. The bonding surface 30a is bonded only to either the first portion 21 (back surface 21a) or the second portion 22 (front surface 22a) of the stabilization layer 20. In the present embodiment, the metal tape 30 is bonded to the front surface 22a of the second portion 22. On the other hand, no metal tape is bonded to the first portion 21. Examples of the metal constituting the metal tape 30 include metals such as copper, copper alloys (e.g., Cu-Zn alloy, Cu-Ni alloy, etc.), aluminum, aluminum alloys, and silver. The thickness of the metal tape 30 is, for example, 50 to 500 μm.

[0033] The bonding surface 30a of the metal tape 30 and the surface 22a of the second portion 22 are bonded to each other by a bonding layer 40. Examples of the bonding material constituting the bonding layer 40 include metals such as solder, Sn, Sn alloy, In (indium), and In alloy. Examples of the solder include alloys such as Sn-Pb based, Pb-Sn-Sb based, Sn-Pb-Bi based, Bi-Sn based, Sn-Cu based, Sn-Pb-Cu based, and Sn-Ag based. However, if the stabilizing layer 20 and the metal tape 30 are electrically bonded, the oxide superconducting wire 1 may not have the bonding layer 40. In this case, the metal tape 30 and the stabilizing layer 20 may be bonded by diffusion bonding or the like.

[0034] As shown in FIG. 1, the width L1 of the metal tape 30 is larger than the width L2 of the stabilizing layer 20. In other words, each side surface 30b of the metal tape 30 is located outside in the width direction X than each side surface 23a of the stabilizing layer 20.

[0035] (Superconducting coil) Next, the superconducting coil C according to the present embodiment will be described. As shown in FIG. 2, the superconducting coil C has a plurality of superconducting coil units CU (pancake coils) laminated in a direction parallel to the central axis O. However, the superconducting coil C may have only one superconducting coil unit CU. In each superconducting coil unit CU, the above-described oxide superconducting wire 1 is wound in a coil shape around the central axis O. The superconducting coil units CU may be electrically connected by a known connection structure. A separator may be provided between two adjacent superconducting coil units CU.

[0036] In the following description, the direction parallel to the central axis O of the superconducting coil C may be referred to as the axial direction. The axial direction is also the direction in which a plurality of superconducting coil units CU are stacked (stacking direction). The direction orthogonal to the central axis O may be referred to as the radial direction. Along the radial direction, the direction approaching the central axis O may be referred to as the inner radial side, and the direction departing from the central axis O may be referred to as the outer radial side. As viewed from the axial direction, the direction of orbiting around the central axis O may be referred to as the circumferential direction or the winding direction.

[0037] In each superconducting coil unit CU, the oxide superconducting wire 1 is wound around the central axis O such that the width direction X of the oxide superconducting wire 1 coincides with the axial direction of the superconducting coil C. In particular, in the present embodiment, the oxide superconducting wire 1 is wound around the central axis O such that the surface 22a (oxide superconducting layer 13) faces the inner radial side and the back surface 21a (substrate 11) faces the outer radial side. That is, the oxide superconducting wire 1 is wound around the central axis O such that the metal tape 30 is located on the inner radial side of the superconducting laminate 10 and the stabilizing layer 20.

[0038] (Method for manufacturing oxide superconducting wire) Next, an example of the method for manufacturing the oxide superconducting wire 1 according to the present embodiment will be described. The method for manufacturing the oxide superconducting wire 1 according to the present embodiment includes a lamination step, a stabilizing layer formation step, and a bonding step.

[0039] In the lamination step, first, a tape-shaped substrate 11 is prepared. Next, an intermediate layer 12, an oxide superconducting layer 13, and a protective layer 14 are sequentially laminated (formed) on the substrate 11. By laminating the layers 12 to 14 on the substrate 11, a tape-shaped superconducting laminate 10 is manufactured. The lamination (film formation) method used in the lamination step is not particularly limited, and a known film formation method may be used. After forming the protective layer 14, oxygen annealing treatment may be performed. The intermediate layer 12 and the protective layer 14 may not be deposited.

[0040] After the lamination process is completed, a cutting process may be performed on the superconducting laminate 10. By performing the cutting process, the superconducting laminate 10 (oxide superconducting layer 13) is cut in the longitudinal direction Z. When the superconducting laminate 10 is cut in this way, a tape-shaped and thinned superconducting laminate 10' having a width smaller than that of the superconducting laminate 10 is cut out from the superconducting laminate 10. The method of cutting the superconducting laminate 10 in the longitudinal direction Z is not particularly limited. For example, the superconducting laminate 10 may be cut using a blade, a laser, or the like.

[0041] In the stabilization layer formation process, a stabilizer is deposited around the superconducting laminate 10 after the lamination process is completed, or around the thinned superconducting laminate 10' after the cutting process is completed, to form the stabilization layer 20. For example, an electroplating method is used for the deposition of the stabilization layer 20. As the metal (stabilizer) used in the electroplating method, for example, the metals described above can be adopted.

[0042] In the bonding process, the stabilization layer 20 and the metal tape 30 are bonded to each other by a bonding material. That is, a bonding layer 40 that bonds the stabilization layer 20 and the metal tape 30 to each other is formed. As the bonding material constituting the bonding layer 40, for example, the metals described above can be used. In the bonding process, a metal tape 30 having a width L1 larger than the width L2 of the stabilization layer 20 is used. The metal tape 30 is bonded to only one of the back surface 21a and the front surface 22a of the stabilization layer 20. In the present embodiment, the metal tape 30 is bonded to the front surface 22a of the stabilization layer 20.

[0043] By performing the lamination process, the stabilization layer formation process, and the bonding process described above, the oxide superconducting wire 1 shown in FIG. 1 is manufactured. A cutting process may be performed after the lamination process. Also, after the bonding process, known processes such as cleaning may be performed.

[0044] Next, the operation of the oxide superconducting wire 1 and the superconducting coil C configured as described above will be described.

[0045] A pancake coil was fabricated using a superconducting oxide wire in which the width L1 of the metal tape 30 is equal to the width L2 of the stabilization layer 20, and a superconducting coil in which these pancake coils are stacked was manufactured. When the superconducting coil is manufactured in this way, in the stacking direction of the superconducting coil (the width direction X of the superconducting oxide wire), one of two adjacent pancake coils and the other pancake coil face each other via a separator. Here, when a current is flowing through the superconducting coil C, an electromagnetic force (Lorentz force) caused by the current flowing through the superconducting oxide wire 1 is applied to the superconducting coil C. Specifically, a force (compressive force) that attempts to compress the superconducting coil C inward in the axial direction and a force (expansive force) that attempts to expand the superconducting coil C outward in the radial direction are applied to the superconducting coil C. When the above-described compressive force is applied to the superconducting coil C, the pancake coils adjacent to each other in the stacking direction compress each other, and a load is applied to the superconducting oxide layer 13 via the stabilization layer 20, which may cause damage or deterioration to the superconducting oxide layer 13.

[0046] On the other hand, in the superconducting oxide wire 1 according to the present embodiment, the width L1 of the metal tape 30 is larger than the width L2 of the stabilization layer 20. With this configuration, even if the pancake coils adjacent to each other in the stacking direction compress each other within the superconducting coil C, although the compressive force is directly applied to the metal tape 30, it does not directly act on the superconducting laminate 10 and the stabilization layer 20. Therefore, it becomes difficult for the superconducting oxide layer 13 to be compressed in the width direction X, and the compressive force applied to the superconducting oxide layer 13 during the operation of the superconducting coil C can be reduced. As a result, the possibility of damage or deterioration occurring in the superconducting oxide layer 13 can be reduced.

[0047] Incidentally, as described above, when manufacturing the superconducting laminate 10´ thinned by cutting using a blade or a laser, the end portions in the width direction X of the oxide superconducting layer 13 may deteriorate, and it is conceivable that the oxide superconducting layer 13 becomes vulnerable to compressive forces in the width direction X. Even in such a case, since the oxide superconducting wire 1 according to the present embodiment has the above-described features, the compressive force applied to the oxide superconducting layer 13 is reduced, and it can be suitably used while suppressing damage to the oxide superconducting layer 13.

[0048] Further, in the oxide superconducting wire 1 according to the present embodiment, the metal tape 30 is joined to only one of the front surface 22a and the back surface 21a of the stabilization layer 20. For this reason, for example, compared with the case where the oxide superconducting wire 1 has two metal tapes 30 and one metal tape 30 is joined to each of the front surface 22a and the back surface 21a of the stabilization layer 20, the thickness of the oxide superconducting wire 1 can be reduced. Further, by manufacturing the superconducting coil C using the oxide superconducting wire 1 having a small thickness, the winding of the oxide superconducting wire 1 can be made denser (see also FIG. 2).

[0049] Further, in the oxide superconducting wire 1 according to the present embodiment, the metal tape 30 is joined to the front surface 22a of the stabilization layer 20. Thereby, for example, compared with the case where the metal tape 30 is joined to the back surface 21a of the stabilization layer 20, the oxide superconducting layer 13 approaches the neutral plane in the thickness direction Y of the oxide superconducting wire 1. For this reason, the stress applied to the oxide superconducting layer 13 when the oxide superconducting wire 1 is bent is reduced. Thereby, for example, when manufacturing the superconducting coil C by winding the oxide superconducting wire 1, the bending strain (compressive strain, tensile strain) generated in the oxide superconducting layer 13 can be reduced. Further, compared with the case where the metal tape 30 is joined to the back surface 21a of the stabilization layer 20, the distance between the metal tape 30 and the oxide superconducting layer 13 can be shortened. Thereby, the overcurrent generated when the oxide superconducting layer 13 transitions to the normal conducting state is likely to be diverted (bypassed) to the metal tape 30.

[0050] However, the configuration of the oxide superconducting wire 1 is not limited to the configuration in which the metal tape 30 is joined to the surface 22a of the stabilization layer 20. For example, as in the oxide superconducting wire 1A shown in FIG. 3, the metal tape 30 may be joined to the back surface 21a of the stabilization layer 20.

[0051] As described above, in each superconducting coil unit CU of the superconducting coil C, the oxide superconducting wire 1A is wound around the central axis O such that the surface 22a faces the radially inner side and the back surface 21a faces the radially outer side. Therefore, when the metal tape 30 is joined to the back surface 21a of the stabilization layer 20, the stabilization layer 20 and the superconducting laminate 10 are located radially inward of the metal tape 30. For this reason, the oxide superconducting layer 13 and the central axis O of the superconducting coil C are close to each other. As a result, when the oxide superconducting wire 1 is wound, a compressive strain is generated in the oxide superconducting layer 13 in the longitudinal direction Z (winding direction).

[0052] As described above, when a current flows through the superconducting coil C, an expansion force that tends to push and expand the superconducting coil C outward in the radial direction is applied to the superconducting coil C. Here, this expansion force acts to extend the oxide superconducting wire 1A (oxide superconducting layer 13) in the longitudinal direction Z. Therefore, by joining the metal tape 30 to the back surface 21a of the stabilization layer 20, the expansion force generated during the operation of the superconducting coil C can be canceled by the compressive strain of the oxide superconducting layer 13. That is, by joining the metal tape 30 to the back surface 21a of the stabilization layer 20, the load applied to the oxide superconducting layer 13 during the operation of the superconducting coil C can be reduced.

[0053] As described above, the oxide superconducting wire 1 according to the present embodiment includes a tape-shaped superconducting laminate 10 including a substrate 11 having a first surface 11a and a second surface 11b opposite to the first surface 11a, and an oxide superconducting layer 13 having a third surface 13a facing the second surface 11b of the substrate 11 and a fourth surface 13b opposite to the third surface 13a; a first portion 21 facing the first surface 11a of the substrate 11; a second portion 22 facing the fourth surface 13b of the oxide superconducting layer 13; and a third portion 23 connecting the first portion 21 and the second portion 22; a stabilizing layer 20 covering the superconducting laminate 10; and a metal tape 30. The width L1 of the metal tape 30 is larger than the width L1 of the stabilizing layer 20, and the metal tape 30 is joined only to either one of the first portion 21 and the second portion 22 of the stabilizing layer 20.

[0054] According to this configuration, since the width L1 of the metal tape 30 is larger than the width L2 of the stabilizing layer 20, in the superconducting coil C, although the compressive force received from the pancake coils adjacent in the stacking direction is applied to the metal tape 30, it does not directly act on the superconducting laminate 10 and the stabilizing layer 20 having a smaller width than the metal tape 30. Therefore, the X-end portion in the width direction of the oxide superconducting layer 13 is less likely to be compressed, and the compressive force applied to the oxide superconducting layer 13 during the operation of the superconducting coil C can be reduced.

[0055] Further, the metal tape 30 is joined to the second portion 22 of the stabilizing layer 20. According to this configuration, for example, compared with the case where the metal tape 30 is joined to the first portion 21 of the stabilizing layer 20, the oxide superconducting layer 13 approaches the neutral plane in the thickness direction Y of the oxide superconducting wire 1. Therefore, the stress applied to the oxide superconducting layer 13 when the oxide superconducting wire 1 is bent is reduced.

[0056] Further, in the superconducting coil C according to the present embodiment, the above-described oxide superconducting wire 1 is wound. According to this configuration, for example, compared with a superconducting coil using an oxide superconducting wire in which the width L1 of the metal tape 30 and the width L2 of the stabilizing layer 20 are equal, the compressive force applied to the oxide superconducting layer 13 during the operation of the superconducting coil C can be reduced.

[0057] Further, the method for manufacturing the oxide superconducting wire 1 according to the present embodiment includes a lamination step of laminating at least one or more layers 12 to 14 including the oxide superconducting layer 13 on the tape-shaped substrate 11 to form the superconducting laminate 10, a stabilizing layer forming step of forming the stabilizing layer 20 around the superconducting laminate 10, and a bonding step of bonding the metal tape 30 having a width L1 larger than the width L2 of the stabilizing layer 20 to only one surface of the stabilizing layer 20. Another method for manufacturing the oxide superconducting wire 1 according to the present embodiment includes a lamination step of laminating at least one or more layers 12 to 14 including the oxide superconducting layer 13 on the tape-shaped substrate 11 to form the superconducting laminate 10, a cutting step of cutting the superconducting laminate 10 in the longitudinal direction Z and cutting out the thinned superconducting laminate 10', a stabilizing layer forming step of forming the stabilizing layer 20 around the thinned superconducting laminate 10', and a bonding step of bonding the metal tape 30 having a width L1 larger than the width L2 of the stabilizing layer 20 to only one surface of the stabilizing layer 20. According to this configuration, the oxide superconducting layer 13 covered by the stabilizing layer 20 is less likely to be compressed, and the compressive force applied to the oxide superconducting layer 13 during the operation of the superconducting coil C can be reduced.

[0058] (Second Embodiment) Next, the second embodiment will be described. The basic configuration is the same as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals and their description is omitted, and only the differences will be described.

[0059] As shown in FIG. 4, in the oxide superconducting wire 2 according to the present embodiment, a recess 31 is formed in the metal tape 30. The recess 31 is recessed upward from the bonding surface 30a of the metal tape 30. The bonding layer 40 is located in the recess 31. At least a part of the stabilizing layer 20 is accommodated in the recess 31.

[0060] According to this configuration, since at least a part of the stabilization layer 20 is accommodated in the recess 31, for example, compared with the case where the recess 31 is not formed in the metal tape 30, the contact area between the stabilization layer 20 and the bonding layer 40 becomes wider. As a result, during the operation of the superconducting coil C, the compressive force transmitted to the stabilization layer 20 (oxide superconducting layer 13) through the metal tape 30 is dispersed, and the compressive force applied to the oxide superconducting layer 13 is further reduced. Also, compared with the case where the recess 31 is not formed in the metal tape 30, the thickness of the oxide superconducting wire 2 can be further reduced.

[0061] As described above, the oxide superconducting wire 2 according to the present embodiment has the recess 31 in which at least a part of the stabilization layer 20 is accommodated. With this configuration, the compressive force applied to the oxide superconducting layer 13 via the metal tape 30 can be reduced.

[0062] Note that the technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0063] For example, like the oxide superconducting wire 3A shown in FIG. 5, the side surface of the bonding layer 40 may not be parallel to the thickness direction Y. As shown in FIG. 5, the side surface of the bonding layer 40 may be inclined so as to gradually face inward in the width direction X in the direction from the metal tape 30 toward the stabilization layer 20. Note that the shape of the side surface of the bonding layer 40 may be a flat surface or a curved surface.

[0064] Like the oxide superconducting wire 3B shown in FIG. 6, the bonding layer 40 may cover at least a part of the third portion 23 of the stabilization layer 20. Alternatively, like the oxide superconducting wire 3C shown in FIG. 7, the bonding layer 40 may cover the first portion 21 of the stabilization layer 20. That is, the bonding layer 40 may cover the entire stabilization layer 20.

[0065] Also, in the superconducting coil C, although it has been described that the oxide superconducting wires 1 and 1A are wound around the central axis O such that the surface 22a (oxide superconducting layer 13) faces radially inward and the back surface 21a (substrate 11) faces radially outward, the configuration of the superconducting coil C is not limited to this. The oxide superconducting wires 1 and 1A may be wound such that the back surface 21a faces radially inward and the surface 22a faces radially outward. However, when the surface 22a faces radially inward and the back surface 21a faces radially outward, the oxide superconducting layer 13 is pressed against the substrate 11 by the expansion force caused by the electromagnetic force described above. Therefore, it is possible to suppress a decrease in superconducting characteristics caused by the oxide superconducting layer 13 being peeled off from the substrate 11.

[0066] Also, in the above embodiment, the cutting process was performed in a state where all of the layers 12 to 14 were deposited on the superconducting laminate 10, but the timing at which the cutting process is performed is not limited to this. For example, the cutting process may be performed when two layers, the intermediate layer 12 and the oxide superconducting layer 13, are deposited on the superconducting laminate 10. In this case, the protective layer 14 may be deposited on the oxide superconducting layer 13 cut out in a tape shape.

[0067] In addition, within the scope not departing from the gist of the present invention, it is possible to appropriately replace the components in the above-described embodiment with well-known components, and the above-described embodiment and modification examples may be appropriately combined.

[0068] For example, the oxide superconducting wire 1A according to the modification example of the first embodiment and the oxide superconducting wire 2 according to the second embodiment may be combined such that the metal tape 30 having the recess 31 is joined to the first portion 21 (back surface 21a) of the stabilization layer 20. Also, a superconducting coil C may be manufactured by winding the oxide superconducting wire 2 provided with the metal tape 30 having the recess 31.

Explanation of Reference Numerals

[0069] 1, 1A, 2, 3A, 3B, 3C... oxide superconducting wire 10... superconducting laminate 11... substrate 11a... first surface 11b... second surface 13... oxide superconducting layer 13a... third surface 13b... fourth surface 13c... side end (end) 20... stabilization layer 21... first portion 22... second portion 23... third portion 30... metal tape 31... recess C... superconducting coil X... width direction

Claims

1. A tape-shaped superconducting laminate including a substrate having a first surface and a second surface opposite to the first surface, and a superconducting oxide layer having a third surface facing the second surface of the substrate and a fourth surface opposite to the third surface; A stabilizing layer having a first portion facing the first surface of the substrate, a second portion facing the fourth surface of the superconducting oxide layer, and a third portion connecting the first portion and the second portion, the stabilizing layer covering the superconducting laminate; A metal tape; wherein a dimension in the width direction of the metal tape is larger than a dimension in the width direction of the stabilizing layer; wherein the metal tape is joined only to one of the first portion and the second portion of the stabilizing layer; The metal tape has a recess in which at least a part of the stabilizing layer is accommodated, the oxide superconducting wire.

2. The oxide superconducting wire according to claim 1, wherein the metal tape is connected to the second portion of the stabilizing layer.

3. A superconducting coil in which the oxide superconducting wire according to claim 1 or 2 is wound.

4. A lamination step of forming a superconducting laminate by laminating at least one layer including a superconducting oxide layer on a tape-shaped substrate; A stabilizing layer forming step of forming a stabilizing layer around the superconducting laminate; A joining step of joining a metal tape having a dimension in the width direction larger than a dimension in the width direction of the stabilizing layer to only one surface of the stabilizing layer, wherein the metal tape has a recess in which at least a part of the stabilizing layer is accommodated, the method for manufacturing an oxide superconducting wire.

5. A lamination step of forming a superconducting laminate by laminating at least one layer including a superconducting oxide layer on a tape-shaped substrate; A cutting step of cutting the superconducting laminate in the longitudinal direction to cut out a thinned superconducting laminate; A stabilizing layer forming step of forming a stabilizing layer around the thinned superconducting laminate; A joining step of joining a metal tape having a dimension in the width direction larger than a dimension in the width direction of the stabilizing layer to only one surface of the stabilizing layer, wherein the metal tape has a recess in which at least a part of the stabilizing layer is accommodated, the method for manufacturing an oxide superconducting wire.

6. A tape-shaped superconducting laminate including a substrate having a first surface and a second surface opposite to the first surface, and a superconducting oxide layer having a third surface facing the second surface of the substrate and a fourth surface opposite to the third surface; A first portion facing the first surface of the substrate, a second portion facing the fourth surface of the oxide superconducting layer, and a third portion connecting the first portion and the second portion, and a stabilizing layer covering the superconducting laminate; A metal tape; A bonding layer bonding the stabilizing layer and the metal tape, and is provided; The dimension in the width direction of the metal tape is larger than the dimension in the width direction of the stabilizing layer; The metal tape is bonded only to one of the first portion and the second portion of the stabilizing layer; An oxide superconducting wire, wherein a side surface of the bonding layer is inclined inward in the width direction as going from the metal tape toward the stabilizing layer.

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