JP2014110104A - Oxide superconductive wire rod, method for producing the same, superconductive coil and superconductive cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconductive wire rod melted to a length direction by a laser beam and free from the generation of oblique motion.SOLUTION: Provided is an oxide superconductive wire rod formed in such a manner that an oxide superconductive laminated body obtained by laminating intermediate layers, oxide superconductive layers and stabilization layers on a tape-shaped base material is irradiated with a laser beam from the outer part of the stabilization layer forming side along the length direction of the oxide superconductive laminated body, and the oxide superconductive laminated body is plurally melted in a vertical split way, in which oblique quantity is 5 mm or lower per m in a length direction.

Description

  The present invention relates to an oxide superconducting wire, a manufacturing method thereof, a superconducting coil, and a superconducting cable.

RE-123 series superconducting wire REBa ₂ Cu ₃ O _(7-x) (RE123: RE is a rare earth element including Y, Gd, etc.) exhibits superconductivity at liquid nitrogen temperature and has low current loss. A superconducting conductor or a superconducting coil for supplying electric power is manufactured by processing into a superconducting wire. As a method for processing this oxide superconductor into a wire, a method of forming an oxide superconducting thin film on a metal base tape via an intermediate layer and forming a stabilization layer on the oxide superconducting thin film Has been implemented.
In addition, since the oxide superconductor crystals have electrical anisotropy, it is necessary to control the crystal orientation when forming the oxide superconducting layer on the base tape. A technique of laminating an oxide superconducting layer on a base tape via an intermediate layer has been implemented. As an example of a technique using this intermediate layer, an ion beam assisted film formation method (IBAD method: Ion Beam Assisted Deposition) is known, and an intermediate layer exhibiting high biaxial orientation is formed on a base tape by this IBAD method. An oxide superconducting laminate having excellent superconducting characteristics can be obtained by forming an oxide superconducting layer on the intermediate layer.

  In order to obtain the target line width in this kind of oxide superconducting laminate, a base tape having the target line width is prepared from the start of production, and an intermediate layer and an oxide superconducting layer are formed thereon. A method of forming an oxide superconducting wire by forming a stabilizing layer is employed. Alternatively, a base tape having a certain line width is prepared in advance, an intermediate layer and an oxide superconducting layer are formed thereon, a stabilizing layer is formed into an oxide superconducting laminate, and the target line is then formed. Research has also been conducted on a method of cutting to a width. Also, considering the ease of manufacturing and the ability to handle various line widths among these manufacturing methods, an oxide superconducting laminate is prepared in advance with a constant line width, and then cut to the target line width. Thus, it is considered that the method of using an oxide superconducting wire is advantageous in terms of production efficiency.

  The dimensions (width, length, thickness) of the oxide superconducting wire are determined according to the purpose of use. However, in the present situation, when producing an oxide superconducting laminate with a certain line width, A superconducting conductor is produced with a width of 10 to 30 mm, and an oxide superconducting wire is obtained by cutting into a line width according to the purpose of use. As an example of the cutting method, a cutter tool having a plurality of sets of two cutting parts is used, and the tape-shaped oxide superconducting laminate is mechanically sandwiched between the cutting edges of the cutting part of the cutter tool, and the width of the oxide superconducting laminate is determined. A method of cutting into a plurality of oxide superconducting wires along the direction is known. However, when such a cutting method is adopted, the oxide superconducting laminate has a laminated structure, and therefore, the oxide superconducting layer is inevitably peeled or deformed near the cut surface, which may lead to deterioration of superconducting characteristics. is there.

  Therefore, a method of fusing by irradiating a continuous wave laser beam, which is a thermal melting type laser beam, on a tape-shaped oxide superconducting laminate has been proposed (see Patent Document 1). This fusing method irradiates a thermal melting type laser beam from the outside of the stabilization layer of the oxide superconducting laminate and heats the stabilization layer, oxide superconducting layer, intermediate layer, and base material of the oxide superconducting laminate. It is known as a method in which peeling or deformation is unlikely to occur in the oxide superconducting layer, which is sequentially melted and melted by a laser beam.

JP 2012-156047 A

However, in the fusing method described in Patent Document 1, as shown in FIG. 8, for example, a plurality of oxide superconducting laminates 101 (two in FIG. 8) are irradiated by irradiating a thermal melting type laser beam. When the oxide superconducting wire 110 is melted, the melted oxide superconducting wire 110 has a problem of bending to the laser beam irradiation part S side (hereinafter referred to as skew).
In the process of irradiating the thermal melting type laser beam to melt the oxide superconducting laminate 101, the oxide superconducting laminate is melted and re-solidified in the vicinity of the laser beam irradiation portion S. At this time, it is considered that the edge 110a of the oxide superconducting wire 110 melted by the thermal melting type laser beam is distorted in the shrinking direction due to re-solidification, thereby causing the oxide superconducting wire 110 to skew.
Such skewing becomes more prominent when the fusing is performed using a continuous wave laser beam capable of speeding up the fusing of the thermal melting type laser beam.

If the oxide superconducting wire 110 is skewed, when it is wound and coiled, the windings become uneven and the quality of the superconducting coil may be degraded.
This skew can be suppressed to some extent by devising the laser output or the like, but if the laser output is suppressed, the cutting speed becomes low and the productivity is poor.

  The present invention has been made in view of the above-described circumstances, and provides an oxide superconducting wire that has been melted and melted using a heat-melting type laser beam and that has a small amount of skew. Objective.

  The present inventor has found that when the amount of skew is 5 mm or less per 1 m in the length direction, it is possible to wind uniformly and to produce a superconducting coil exhibiting stable performance. . Accordingly, the inventors have found an oxide superconducting wire and a method for manufacturing the same, in which the amount of skewing is 5 mm or less per 1 m in the length direction even when melted by a heat melting type laser beam, and have completed the present invention.

In order to solve the above-mentioned problems, the oxide superconducting wire of the present invention provides a laser beam to the oxide superconducting laminate in which an intermediate layer, an oxide superconducting layer and a stabilizing layer are laminated on a tape-like substrate. An oxide superconducting wire formed by irradiating along the length direction of the oxide superconducting laminate from the outer side of the layer forming side and fusing the oxide superconducting laminate into a plurality of pieces, Is 5 mm or less per 1 m in the length direction.
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the oxide superconducting wire which can be wound evenly because the amount of skewing is 5 mm or less per 1 m in the length direction.

The oxide superconducting wire of the present invention is the oxide superconducting wire described above, wherein the oxide superconducting wire is formed by fusing using a continuous wave laser beam as the laser beam.
According to the present invention, since fusing is performed by a continuous wave laser beam, it is possible to provide an oxide superconducting wire that is highly productive and inexpensive.

The superconducting cable of the present invention is characterized by having the oxide superconducting wire.
By producing a superconducting cable using the oxide superconducting wire, the amount of skew of the oxide superconducting wire is small, so the forming accuracy when producing a superconducting cable by spirally winding the oxide superconducting wire is high. Thus, the oxide superconducting wire can be wound at a higher density, and a high-performance superconducting cable can be produced.
In addition, since the superconducting cable has the oxide superconducting wire uniformly wound inside, the superconducting cable has no locality in terms of flexibility and is easy to handle.

The superconducting coil of the present invention is characterized by having the oxide superconducting wire.
Since the superconducting coil produced by winding the oxide superconducting wire has a small skew amount of the oxide superconducting wire, the deviation in the coil height direction (that is, the wire width direction) is small. Therefore, when this superconducting coil is laminated and a cooling plate is disposed between the superconducting coils, the oxide superconducting wire constituting the superconducting coil uniformly contacts the cooling plate, so that the contact area between the superconducting coil and the cooling plate is reduced. Increases cooling efficiency.
In addition, since the winding accuracy at the time of winding the coil is high, the separation between the analysis value and the actual measurement value can be suppressed, and the superconducting coil can exhibit the performance as designed.

The method for producing an oxide superconducting wire according to the present invention comprises a step of laminating an intermediate layer, an oxide superconducting layer and a stabilizing layer on a tape-like substrate to form an oxide superconducting laminate, and the oxide superconducting laminate. Then, a laser beam is irradiated along the length direction of the oxide superconducting laminate from the outside on the stabilization layer forming side to cut the oxide superconducting laminate into a plurality of pieces, thereby forming an oxide superconducting wire. The step of irradiating the oxide superconducting laminate by irradiating the laser beam and expanding the portion that has already been fused to the irradiation path of the laser beam, and applying strain. It is characterized by fusing.
ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the oxide superconducting wire which can be wound evenly because the amount of skewing is 5 mm or less per 1 m in the length direction. In addition, since fusing is performed by a laser beam, an oxide superconducting wire that is highly productive and inexpensive can be provided.

Moreover, the manufacturing method of the oxide superconducting wire of the present invention is characterized in that the strain is 0.02 to 0.33%.
According to the present invention, by setting the strain to 0.02 to 0.33%, the skew amount of the oxide superconducting wire can be set to 5 mm or less per 1 m in the length direction. In addition, providing the oxide superconducting wire in which the crystal structure of the oxide superconducting layer 6 of the oxide superconducting wire 10 is not cracked and the superconducting properties are not deteriorated by setting the strain to 0.33% or less. can do.

Moreover, the manufacturing method of the oxide superconducting wire of the present invention is characterized by fusing using a continuous wave laser beam as the laser beam.
According to the present invention, since fusing is performed by a continuous wave laser beam, it is possible to provide an oxide superconducting wire that is highly productive and inexpensive.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the oxide superconducting wire which can be wound evenly because the amount of skewing is 5 mm or less per 1 m in the length direction. In addition, an oxide superconducting wire whose superconducting properties are not deteriorated can be provided.
Further, in the case of fusing with a continuous wave laser beam, an oxide superconducting wire with high productivity and low cost can be provided.

FIGS. 1A and 1B are partial cross-sectional perspective views before melting and FIG. 1B are partial cross-sectional perspective views after fusing. FIGS. It is a perspective schematic diagram which shows the fusing method of the oxide superconducting laminated body which concerns on this invention. It is a schematic diagram which shows the mode at the time of fusing of an oxide superconducting laminated body. It is a schematic diagram which shows an example of the state which irradiates the thermal fusion type laser beam to the oxide superconducting laminated body by the laser beam irradiation apparatus, and is blown out. It is a perspective schematic diagram which shows the state which formed the insulation coating by the insulating tape in the oxide superconducting wire after fusing. It is a partial section schematic diagram showing an example of a superconducting cable. It is a perspective view which shows an example of a superconducting coil. It is a plane schematic diagram which shows the fusing method of the oxide superconducting laminated body 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.
Although the present invention relates to an oxide superconducting wire formed by fusing an oxide superconducting laminate with a laser beam, it is preferable to use a thermal melting type laser beam as the laser beam, which is used in this embodiment. The laser beam to be used is a heat melting type laser beam.

(Oxide superconducting wire)
The oxide superconducting laminate 1 to be cut in the present invention has an intermediate layer 5, an oxide superconducting layer 6 and a first stable layer on a metal tape-like substrate 3 as shown in FIG. The oxide superconducting laminate 1 is cut by a thermal melting type laser beam B as will be described later, so that the width is smaller than that of the oxide superconducting laminate 1 as shown in FIG. A plurality (two in FIG. 1B) of oxide superconducting wires 10 can be obtained.
Since this oxide superconducting wire 10 is formed by cutting the oxide superconducting laminate 1 in the width direction, the oxide superconducting wire 10 has exactly the same structure except for its narrow width. An intermediate layer 5a, an oxide superconducting layer 6a, and a first stabilizing layer 7a are laminated on a metal tape-like substrate 3a.

More specifically, as shown in FIG. 5, the oxide superconducting wire 10 has an intermediate layer 5a composed of a diffusion prevention layer 11, a bed layer 12, an alignment layer 15, and a cap layer 16 laminated on the upper surface of the base material 3a. The oxide superconducting layer 6a and the first stabilizing layer 7a are laminated thereon, but in FIG. 1, the intermediate layer 5a is drawn as one layer for the sake of simplicity of illustration. Note that the diffusion preventing layer 11, the bed layer 12, and the cap layer 16 are not essential and may be omitted in some cases.
The oxide superconducting wire 10 shown in FIG. 5 shows a state in which a thicker second stabilizing layer 8 is laminated on the first stabilizing layer 7a, and the oxide superconducting wire 10 and the second stabilizing layer are shown. An insulating layer 18 is formed by winding a resin tape 17 around the entire circumference of the laminate composed of the layer 8.
The second stabilization layer 8 is bonded or plated after the oxide superconducting wire 10 is obtained as shown in FIG. 1B by cutting the thermal melting type laser beam B along the irradiation path P. Is formed.
As the structure shown in FIG. 5, the oxide superconducting wire 10 insulated with the insulating layer 18 can be coiled to be used for applications such as a superconducting coil, and the oxide superconducting wire 10 insulated with the insulating layer 18 is used. It can be used for applications such as superconducting cables for power transmission.
Hereinafter, each element of the oxide superconducting wire 10 will be described.

  The base material 3 (3a) 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. The material used for the base material 3 (3a) is preferably a material having high mechanical strength, heat resistance, and a metal that can be easily processed into a wire, such as stainless steel, hastelloy, etc. And various heat-resistant metal materials such as nickel alloys, 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. Further, as the base material 3 (3a), an oriented Ni—W alloy tape base material in which a texture is introduced into a nickel alloy can also be applied. What is necessary is just to adjust the thickness of the base material 3 (3a) suitably according to the objective, Usually, 10-500 micrometers, Preferably it is 20-200 micrometers.

The diffusion prevention layer 11 is formed for the purpose of preventing the diffusion of the constituent elements of the base material 3 (3a), and has a relatively high effect of preventing the mixing of impurities, Al ₂ O ₃ , Si ₃ N ₄ , or GZO. A single-layer structure or a multi-layer structure composed of (Gd ₂ Zr ₂ O ₇ ) or the like is desirable, and the film is formed by a film forming method such as a sputtering method.
The bed layer 12 has high heat resistance and is intended to reduce interfacial reactivity, and is used to obtain the orientation of a film disposed thereon. Such a bed layer 12 is made of, for example, rare earth such as Y ₂ O ₃ , CeO ₂ , La ₂ O ₃ , Dy ₂ O ₃ , Er ₂ O ₃ , Eu ₂ O ₃ , and Ho ₂ O ₃ with high heat resistance. A single layer structure or a multilayer structure composed of an oxide is desirable.

The alignment layer 15 controls the crystal orientation of the cap layer 16 and the oxide superconducting layer 6 (6a) formed thereon, or the constituent element of the substrate 3 (3a) is the oxide superconducting layer 6 (6a). It has a function of suppressing diffusion to the base material, and relaxing a difference in physical properties such as a coefficient of thermal expansion and a lattice constant between the base material 3 (3a) and the oxide superconducting layer 6 (6a). . The material of the alignment layer 15 is not particularly limited as long as it can exhibit 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 a later-described ion beam assisted vapor deposition method (hereinafter sometimes referred to as IBAD method), a layer having high crystal orientation is obtained, and the crystal orientation of the cap layer 16 and the oxide superconducting layer 6 (6a) is further improved. Since it can be made favorable, it is particularly suitable.

The cap layer 16 is epitaxially grown by being formed on the surface of the orientation layer 15 in which the in-plane crystal axes are oriented as described above, and then grows laterally, so that the crystal grains are self-oriented in the in-plane direction. Although it if not particularly limited and may be _{material, CeO 2, LaMnO 3, Y} 2 O 3, Al 2 O 3, Gd 2 O 3, ZrO 2, Ho 2 O 3, Nd 2 O 3, Zr 2 O 3 , etc. The metal oxide is preferable from the viewpoint of lattice matching with the oxide superconducting layer 6 (6a). Among these, CeO ₂ and LaMnO ₃ are particularly preferable from the viewpoint of matching with the oxide superconducting layer 6 (6a).
Here, when CeO ₂ is used for the cap layer 16, the cap layer 16 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 6 (6a) has a function of flowing current when in the superconducting state. As the material used for the oxide superconducting layer 6 (6a), a material composed of an oxide superconductor having a generally known composition can be widely applied. For example, RE-123 series superconductor, Bi series superconductor. And copper 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 6 (6a) used in the present invention is a copper oxide superconductor. Unless otherwise specified, the material used for the oxide superconducting layer 6 (6a) is copper-oxidized. A superconductor.

The first stabilization layer 7 (7a) laminated on the oxide superconducting layer 6 (6a) has good conductivity such as Ag and has low contact resistance with the oxide superconducting layer 6 (6a). It is formed as a layer made of a metal material. The thickness of the Ag first stabilizing layer 7 (7a) can be formed to about 1 to 30 μm.
The second stabilization layer 8 is provided for stabilization of the oxide superconducting layer 6a, and is formed from a highly conductive metal material such as Cu or Cu alloy. In addition, when applying the oxide superconducting wire 10 for the purpose of a current limiting device or the like, it is preferable to use a high resistance material as the second stabilization layer 8, and thus a metal material having a high resistance to Cu or Ag such as NiCr. Can be configured. The second stabilization layer 8 can be formed to a thickness of about 100 to 300 μm.

  In the wire composed of the oxide superconducting wire 10 and the second stabilizing layer 8 formed as described above, the insulating layer 18 is formed by winding the resin tape 17 around the entire circumference. The wire on which the insulating layer 18 is formed can be used as a superconducting coil by winding it into a coil. In that case, the oxide superconducting wire 10 is wound around the winding core made of a material such as FRP by a predetermined number of turns. Further, the coil itself is impregnated with a thermosetting resin such as an epoxy resin for the purpose of fixing and reinforcing the oxide superconducting wire 10 to have a structure strong against external force.

(Fusing method)
Below, the schematic structure of the laser beam irradiation apparatus 20 used for this invention and the fusing method of the oxide superconducting laminated body 1 by the thermal fusion type laser beam B using the said laser beam irradiation apparatus 20 are demonstrated.
In the present embodiment, a case where the oxide superconducting laminate 1 is blown at a high speed by irradiating a continuous wave laser beam as the thermal melting type laser beam B will be described. However, the present invention is applicable to the fusing of the oxide superconducting laminate 1 using, for example, a pulsed laser beam, as long as the laser beam output form is any heat melting type laser beam.
FIG. 4 shows a schematic configuration of a laser beam irradiation apparatus 20 used for generating the thermal melting type laser beam B to cut the oxide superconducting laminate 1. The laser beam irradiation device 20 of this example includes a plurality of (three in the example of FIG. 4) excitation laser light emitting devices 21 and a beam complier that couples the excitation lasers from the plurality of light sources through the connection fibers 21a. A coupler 22 as an inner, an amplification fiber 23 composed of a double clad fiber connected to the coupler 22, a transmission fiber 24 connected to the amplification fiber 23, and a tip of the transmission fiber 24. The connected output unit 25 is mainly used.

  As an example, the amplifying fiber 23 may be a rare earth-doped fiber that is an optical amplifying medium. As a rare earth-doped fiber, a rare-earth element, for example, a core to which rare-earth elements such as Yb (ytterbium), Er (erbium), Tm (thulium), Nd (neodymium), Pr (praseodymium) are added, and the outer periphery of the core are surrounded. A rare earth-doped double clad fiber composed of a first clad and a second clad surrounding the first clad can be used.

The output unit 25 is connected to a cylindrical guide unit 26 for introducing a laser output from the transmission fiber 24, an optical device 27 accommodated on the upper side of the guide unit 26, and a lower side of the guide unit 26. The nozzle body 28 and the gas supply source 29 connected to the lower side of the nozzle body 28 are mainly configured.
The optical device 27 includes a plurality of optical lenses, and by adjusting the mutual position of these optical lenses, the spot diameter of the laser light incident from the transmission fiber 24 is reduced and the tip of the nozzle body 28 is removed. On the other hand, the laser beam can be condensed and irradiated so as to have an appropriate spot diameter.
A gas introduction part 30 is formed on the upper side wall of the nozzle body 28, and a gas supply source 29 such as an inert gas is connected to the gas introduction part 30. The shield gas G can be ejected from the opening of the tip of the nozzle body 28 by sending a shield gas G such as an inert gas from the gas supply source 29 into the nozzle body 28.

  Using the laser beam irradiation apparatus 20 described above, as shown in FIG. 1, the tip of the nozzle body 28 is positioned at the center in the width direction of the oxide superconducting laminate 1 installed horizontally and irradiated with the thermal melting type laser beam B. While irradiating along the path P, the oxide superconducting laminate 1 is moved at a predetermined speed while applying tension in its length direction. Note that the tension applied to the oxide superconducting laminate 1 is a tension that does not deteriorate the superconducting characteristics of the oxide superconducting laminate 1 and that enables smooth movement. Specifically, it is preferably 1 to 20 kgf.

  In the laser beam irradiation device 20, the multimode excitation light input from the excitation light emitting device 21 to the coupler 22 via the connection fiber 21a is optically coupled by the coupler 22 and input to the amplification fiber 23, and is used for amplification. Wavelength amplification and output amplification are performed in the fiber 23, converted into a single mode, and output as a thermal melting type laser beam B through the transmission fiber 24.

As an example of the thermal melting type laser beam B applied in the present embodiment, a continuous wave laser beam having a center wavelength of 1080 nm can be used, and the thermal melting type laser beam B is collected outside the tip of the nozzle body 28 with a beam output of 300 W. The spot diameter on the beam tip side in the case of light irradiation can be about 10 μm to 500 μm. The center wavelength of the heat melting type laser beam can be set to a wavelength of about 1050 to 1100 nm.
As an example, the spot diameter of the laser beam irradiation part S is about 20 μm. If the spot diameter of the laser beam irradiation part S is too large, the fusing width of the base material 3 is increased, and the oxide superconducting layer 6 is lost with a large width. Therefore, the spot diameter is preferably 500 μm or less. Is preferably set to 100 μm or less.

  When the spot diameter is reduced to about 20 μm by adjusting the optical device 27 with respect to the thermal melting type laser beam B and the surface of the oxide superconducting laminate 1 is irradiated from the tip of the nozzle body 28 as described above, the oxide superconducting laminate The first stabilizing layer 7, the oxide superconducting layer 6, the intermediate layer 5, and the base material 3 can be blown out by the heat melting type laser beam B along the longitudinal direction of the oxide superconducting laminate 1.

  Further, since the thermal melting type laser beam B is irradiated from the outside of the first stabilizing layer 7, the first stabilizing layer 7, the oxide superconducting layer 6, and the intermediate layer 5 in the oxide superconducting laminate 1. The laser beam irradiation part S can be sequentially melted in the order of the base material 3, but the amorphous melt generated at that time is removed by being blown off by the shield gas G ejected from the tip of the nozzle body 28.

In performing this fusing, as shown in FIG. 2, the pair of oxide superconducting wires 10 and 10 sent in the feed direction Y and cut in the laser beam irradiation section S are guided by guide rolls 40 and 40, respectively. It is held in a direction perpendicular to the direction Y.
However, FIG. 2 is a schematic diagram showing an enlarged portion that is a feature for convenience in order to make the characteristics of the fusing method according to the present embodiment easier to understand. Not always.

The guide rolls 40 are individually rotatably installed along the feed direction Y of the oxide superconducting wire 10. Further, the guide roll 40 is a disc that guides both sides of the melted oxide superconducting wire 10 along the feed direction Y along the shaft portion 40b on which the oxide superconducting wire 10 is placed and both sides thereof. Shaped guide portions 40a, 40a. The guide portions 40a and 40a are arranged slightly apart from the width (= D / 2) of the oxide superconducting wire 10 fused through the shaft portion 40b.
The guide rolls 40 and 40 are arranged at a distance H along the feed direction Y with respect to the laser beam irradiation unit S, and guide the oxide superconducting wires 10 and 10.

  The pair of guide rolls 40, 40 are arranged apart from each other in the direction perpendicular to the feed direction Y of the oxide superconducting wire 10 (the width direction of the oxide superconducting wire 10). Thereby, the melted oxide superconducting wires 10 and 10 are gradually separated as they are sent in the feeding direction Y, and when they reach the guide rolls 40 and 40, the width of the oxide superconducting wire 10 is increased. They are separated by a distance L in the direction. That is, in the laser beam irradiation section S, the edge portions 10a and 10a on the laser beam irradiation section S side of the oxide superconducting wires 10 and 10 formed adjacent to each other are fed in the feed direction Y by a distance H. The distance L is separated in the direction perpendicular to the direction Y.

  The oxide superconducting wires 10 and 10 are expanded by the guide rolls 40 and 40 outward in the width direction with respect to the irradiation path P of the thermal melting type laser beam B as they are sent along the feed direction Y. Therefore, between the laser beam irradiation part S and the guide rolls 40, 40, the pair of oxide superconducting wires 10, 10 is bent in a direction away from each other (that is, outward direction with respect to the irradiation path P). Stress is applied. This bending stress can be described as a tensile stress in the feed direction Y that maximizes the edges 10a and 10a in the width (D / 2) of the oxide superconducting wire 10, and the edges 10a and 10a A strain in the tensile direction according to the tensile stress occurs. This distortion is in a direction opposite to the contraction in the contraction direction that occurs when the laser beam irradiation unit S melts and re-solidifies, and suppresses skew caused by melting and re-solidification. Hereinafter, this distortion is called reverse distortion.

The reverse strain (hereinafter referred to as ε) represents a strain in the tensile direction according to the tensile stress at the edge 10a of the oxide superconducting wire 10, and the width (D / 2) of the oxide superconducting wire 10 in FIG. The distance (H) along the feed direction Y of the guide roll 40 with respect to the laser beam irradiation unit S and the distance (L / 2) in the X direction orthogonal to the feed direction Y can be calculated.
Hereinafter, a method for calculating the inverse strain ε will be described with reference to FIG. 3 schematically showing FIG. 2. It is assumed that the oxide superconducting wire 10 and the guide roll 40 are in point contact at a point Q in FIG.

The oxide superconducting wire 10 is bent in the X direction by the guide roll 40, so that the edge thereof is bent as shown in FIG. This curved curve can be approximated as an arc having a constant curvature, and the radius of curvature at this time is R. In addition, a linear distance from the laser beam irradiation part S to the contact point Q between the oxide superconducting wire 10 and the guide roll 40 (that is, the chord length of a circle having a radius R) is x.
Further, two equal angles of an isosceles triangle connecting the arc center and the chord having a chord length x are defined as θ.

式（１）〜（４）によって、曲率半径Ｒを求めることができる。 At this time, the following relational expression holds.

The curvature radius R can be obtained by the equations (1) to (4).

式（５）に、ｒ、ｄ、並びに式（１）〜（４）によって算出されるＲを代入してまとめると、

となる。 Here, by assuming that the oxide superconducting wire 10 generates a symmetrical stress in the cross section by bending, the reverse strain ε is expressed by the following equation (5). In equation (5), r represents the distance from the point where the reverse strain ε occurs to the neutral point (the point at which the stress becomes 0), and d represents the position of the neutral point. Therefore, r = D / 4 and d = D / 4.

Substituting r calculated by Equations (5) and R and Equations (1) to (4) into Equation (5),

It becomes.

In the present specification, the inverse strain ε is calculated using the equation (6).
Further, the distance H along the feed direction Y between the guide roll 40 and the laser beam irradiation unit S is fixed, and the distance L between the pair of oxide superconducting wires 10 and 10 is appropriately changed at the distance H. Can be adjusted as appropriate.

  By the way, as explained based on FIG. 8, when the conventional oxide superconducting laminate 101 is blown (that is, when reverse strain is not applied at the time of fusing), the pair of oxide superconducting wires 110 and 110 includes: The laser beam irradiating part S is curved (ie, inward), and a skew exceeding 5 mm per 1 m in the length direction appears. Oxide superconducting wire 110 having a skew of more than 5 mm per meter makes stable winding difficult, and the quality of the superconducting coil having such winding may be lowered. If the amount of skew is 5 mm or less per meter, uniform winding can be performed, and a superconducting coil that exhibits stable performance can be produced.

  As described above, since the oxide superconducting wires 10 and 10 are reversely strained at the time of melting, skewing is suppressed. However, if the reverse strain is excessively increased (that is, if the distance L is excessively increased), the oxide superconducting wire 10 bends on the side opposite to the laser beam irradiation part S side (that is, outward) and exceeds 5 mm. Show. In addition, there is a possibility that the crystal structure of the oxide superconducting layer 6 of the oxide superconducting wire 10 is cracked and the superconducting properties are deteriorated. The present inventor has found that it is effective to apply a reverse strain of 0.02% or more and 0.33% or less through intensive studies. That is, by setting the reverse strain to 0.02% or more and 0.33% or less, it is possible to obtain the oxide superconducting wire 10 having a skew amount per 1 m in the length direction of 5 mm or less. If the reverse strain is 0.33% or less, the superconducting characteristics of the oxide superconducting wire 10 are not deteriorated.

  In the present embodiment, the case where one oxide superconducting laminate 1 having a width D by the thermal melting type laser beam B is fused to two oxide superconducting wires 10 and 10 having a width D / 2 has been described. However, even when one oxide superconducting laminate 1 is divided into three or more oxide superconducting wires 10, 0.02 to 0.33 in order from the widthwise end of the oxide superconducting laminate 1. The oxide superconducting wire 10 having a skew amount of 5 mm or less per 1 m in the length direction can be obtained by fusing while applying reverse strain of%.

(Superconducting cable)
The oxide superconducting wire 10 manufactured as described above 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 10 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 forming the superconducting cable 80 using the oxide superconducting wire 10, the forming accuracy when the superconducting cable 80 is formed by spirally winding the oxide superconducting wire 10 is increased, and the oxide superconducting is denser. The wire 10 can be wound and the high-performance superconducting cable 80 can be manufactured.
In addition, since the superconducting cable 80 has the oxide superconducting wire 10 spirally wound inside, the superconducting cable 80 has no locality in terms of flexibility and is easy to handle.

(Superconducting coil)
As an example, a superconducting coil 90 shown in FIG. 7 can be configured using the oxide superconducting wire 10 manufactured as described above. Superconducting coil 90 has a structure in which a plurality of pancake coils 91 produced by winding oxide superconducting wire 10 (not shown in FIG. 7) are stacked. Hereinafter, the structure of the superconducting coil 90 will be described with reference to FIG.
A pair of donut-shaped pancake coils 91, 91 are laminated coaxially in the thickness direction to constitute a double pancake coil 92. The double pancake coil 92 is laminated in three layers in the thickness direction to form a coil laminate 93. The flange plates 94 and 95 are in contact with the upper end surface 93a and the lower end surface 93b of the coil laminate 93, respectively. Has been placed. A cooling plate 97 is interposed between the stacked double pancake coils 92, 92. Further, a superconducting coil 90 is configured by mounting a coil laminate 93 on a bobbin C in which opposed flange plates 94 and 95 are integrated by a winding drum 96.

Since the pancake coil 91 produced by winding the oxide superconducting wire 10 has a small amount of skew of the oxide superconducting wire 10, the deviation in the coil height direction (that is, the wire width direction) is small.
Therefore, the oxide superconducting wire 10 constituting the pancake coil 91 uniformly contacts the cooling plate 97 inserted above or below the pancake coil 91 and the contact area between the pancake coil 91 and the cooling plate 97 increases. Therefore, the cooling efficiency of the superconducting coil 90 is improved.
In addition, since the winding accuracy at the time of coil winding is high, the separation between the analysis value and the actual measurement value can be suppressed, and the superconducting coil 90 can exhibit the performance as designed.

The oxide superconducting wire 10 of the present invention can be used for various superconducting devices.
Here, the superconducting device is not particularly limited as long as it has the oxide superconducting wire 10, and examples thereof include 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)
A tape-shaped substrate having a width of 10 mm, a thickness of 0.075 mm, and a length of 30 m made of Hastelloy C276 (trade name of Haynes, USA) is prepared, and the surface roughness Ra is obtained by Al ₂ O ₃ abrasive grains having an average particle diameter of 2 nm. After polishing to 4-5 nm, it was washed with an organic solvent (ethanol or acetone). Next, a diffusion prevention layer having a thickness of 100 nm made of Al ₂ O ₃ was formed on the surface of the base material by ion beam sputtering. Further, a 30 nm thick bed layer made of Y ₂ O ₃ was formed on the diffusion preventing layer by ion beam sputtering. Next, an alignment layer of MgO having a thickness of 5 to 10 nm was formed on the bed layer using the IBAD method. Subsequently, a cap layer of CeO _{2 having} a thickness of 500 nm was formed on the MgO alignment layer using a pulsed laser deposition method (PLD method). Furthermore, an oxide superconducting layer having a thickness of 2 μm of GdBa ₂ Cu ₃ O _(7-x) was formed on the cap layer by a pulse laser deposition method. Next, an Ag stabilizing base layer having a thickness of 2 μm was formed on the oxide superconducting layer by sputtering, oxygen annealing was performed at 500 ° C. for 10 hours, and the furnace was cooled for 26 hours and then taken out. An oxide superconducting laminate was produced by the above method.
This oxide superconducting wire is commonly used in the following examples and comparative examples.

  The above-described oxide superconducting laminate is irradiated with a continuous wave laser beam, which is a thermal melting type laser beam having the output shown in Table 1, at the center in the width direction, and is given in Table 1 at a feed rate of 800 m / h while applying a tension of 9 kgf. The oxide superconducting laminate was melted and cut into two oxide superconducting wires having a width of 5 mm while applying reverse strain of Examples 1 to 12 and comparative examples were prepared. Sample No. The comparative example of 8 does not apply reverse strain.

(Evaluation method)
Sample No. Table 1 shows the results of measuring the amount of skew per 1 m in the length direction of 1 to 12 oxide superconducting wires.
As defined in JIS H4551, the method of measuring the amount of skew is to cut each sample 1 m, place the sample on a surface plate with both ends grounded, and place the center part (ie 50 mm from the end part). The gap with the surface plate of (part) was measured.
The two values of the amount of skew are the measurement results of the two cut oxide superconducting wires.
Further, the amount of skew is described with the inside skew as positive with respect to the path of the laser beam irradiation part. That is, a negative value indicates that the laser beam is skewed outward with respect to the path of the laser beam irradiation unit.

  Moreover, the critical current before and after fusing was measured as an evaluation of the superconducting characteristics. The critical current is determined by a magnetization measuring device (made by THEVA) at 77K. The critical current values before and after fusing were compared, and those with a critical current value decrease of 5% or more were shown in Table 1 with x being less than 5%.

(Comparison of Examples and Comparative Examples)
Sample No. In the examples of 2 to 7 and 9 to 11, various reverse distortions are applied, but the skew amount is 5 mm or less. In addition, an oxide superconducting wire having no deterioration in superconducting properties could be obtained. In addition, Sample No. with 0.02% reverse strain applied thereto. In Example 9, since the implementation result of 5 mm, which is the boundary value of the skew amount of the present invention, was obtained, by applying a reverse strain of 0.02% or more, the oxidation having the skew amount of 5 mm or less. It is thought that a superconducting wire can be obtained.
On the other hand, Sample No. with reverse strain exceeding 0.33% applied. In the comparative examples 1 and 12, the amount of skew is large (5 mm or more). Sample No. Regarding No. 1, since the superconducting characteristics were deteriorated, it is considered that the crystal structure of the oxide superconducting layer was cracked by the application of reverse strain.
In addition, sample no. In the comparative example of 8, the skew amount is large (5 mm or more).
From these, the superiority of the oxide superconducting wire according to the present invention was confirmed.

DESCRIPTION OF SYMBOLS 1,101 ... Oxide superconducting laminated body, 3, 3a ... Base material, 5, 5a ... Intermediate | middle layer, 6, 6a ... Oxide superconducting layer, 7, 7a ... 1st stabilization layer, 8 ... 2nd stability 10 ... 110 oxide superconducting wire, 10a ... edge, 11 ... diffusion prevention layer, 12 ... bed layer, 15 ... alignment layer, 16 ... cap layer, 17 ... resin tape, 18 ... insulating layer, 20 ... Laser beam irradiation device, 21 ... light emitting device, 21a ... connecting fiber, 22 ... coupler, 23 ... amplifying fiber, 24 ... transmitting fiber, 25 ... output unit, 26 ... guide unit, 27 ... optical device, 28 ... Nozzle body, 29 ... gas supply source, 30 ... gas introduction part, 40 ... guide roll, 40a ... guide part, 40b ... shaft part, 80 ... superconducting cable, 90 ... superconducting coil, B ... heat melting type laser beam, G ... Shield gas, H, L ... Distance , P ... illumination pathway, S ... laser beam irradiation unit, Y ... feeding direction

Claims (7)

The oxide superconducting laminate in which an intermediate layer, an oxide superconducting layer, and a stabilizing layer are laminated on a tape-like base material is irradiated with a laser beam from the outside of the stabilizing layer forming side to the length of the oxide superconducting laminate. An oxide superconducting wire formed by irradiating along the length direction and vertically cutting the oxide superconducting laminate into a plurality of pieces,
An oxide superconducting wire characterized by having a skew amount of 5 mm or less per 1 m in the length direction.   The oxide superconducting wire according to claim 1, wherein the oxide superconducting wire is formed by fusing using a continuous wave laser beam as the laser beam.   A superconducting cable comprising the oxide superconducting wire according to claim 1 or 2.   A superconducting coil comprising the oxide superconducting wire according to claim 1. A step of laminating an intermediate layer, an oxide superconducting layer and a stabilizing layer on a tape-shaped substrate to form an oxide superconducting laminate;
The oxide superconducting laminate is irradiated with a laser beam along the length direction of the oxide superconducting laminate from the outside on the stabilization layer forming side, and the oxide superconducting laminate is cut into a plurality of pieces, and then oxidized. Forming a superconducting wire material,
In the step of fusing the oxide superconducting laminate by irradiating with the laser beam, a portion that has already been fused with respect to the irradiation path of the laser beam is spread outward in the width direction, and is melted by applying strain. A method of manufacturing an oxide superconducting wire.   6. The method for producing an oxide superconducting wire according to claim 5, wherein the strain is 0.02 to 0.33%.   The method for producing an oxide superconducting wire according to claim 5 or 6, wherein the laser beam is melted by using a continuous wave laser beam.

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