JP2017152210A - Oxide superconducting wire and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconducting wire capable of suppressing detachment of an oxide superconducting layer from an edge part of a wide direction as an origin and a manufacturing method therefor.SOLUTION: There is provided an oxide superconducting wire containing a superconductive laminate 6 having an intermediate layer 2 and an oxide superconducting layer 3 laminated on one surface 1b of a metal substrate 1 in this order, further a protective layer 4 covering at least a surface of the oxide superconducting layer 3, and a non-oriented area 3b over a longer direction at an edge part in a width direction of the oxide superconductive layer 3.SELECTED DRAWING: Figure 2

Description

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

In recent years, oxide superconducting wires using yttrium-based superconductors represented by the general formula REBa ₂ Cu ₃ O _7-δ (RE123) have been developed vigorously because of their high tensile strength and critical current in magnetic fields. Is underway. The rare earth element RE is not limited to yttrium (Y).

  Yttrium-based oxide superconducting wire has a force in a direction perpendicular to the main surface of the metal substrate due to the structure in which an oxide thin film including an oxide superconducting layer is laminated on one surface (main surface) of the metal substrate. Is known to be relatively weak. Also, the superconducting coil produced by impregnating the winding of tape-like yttrium oxide superconducting wire into a resin such as epoxy has a direction perpendicular to the wire during cooling due to the difference in coefficient of linear expansion of each component. There is a risk that the oxide superconducting layer may be broken or deteriorated by the tensile stress of.

  As a method for producing an yttrium-based oxide superconducting wire, an intermediate layer, an oxide superconducting layer, a protective layer, etc. are laminated on a wide metal substrate of 10 mm, 12 mm, etc., and then thinned to a width of 4 mm, 5 mm, etc. There are cases (see, for example, Patent Document 1).

JP 2012-226857 A

  When a laminated body including an oxide superconducting layer is processed into fine wires, damage such as cracks is applied to the oxide superconducting layer. Therefore, when peeling stress acts on the wire, the oxide superconductivity starts from the cut surface at the end in the width direction. May cause delamination.

  This invention is made | formed in view of the said situation, and provides the oxide superconducting wire which can suppress peeling of the oxide superconducting layer from the edge part of the width direction, and its manufacturing method. Let it be an issue.

  In order to solve the above problems, the present invention provides an intermediate layer and an oxide superconducting layer laminated in this order on one surface of a metal substrate, and further provided with a protective layer covering at least the surface of the oxide superconducting layer. There is provided an oxide superconducting wire comprising the superconducting laminate formed, wherein the oxide superconducting wire has a non-oriented region extending in the longitudinal direction at an end in the width direction of the oxide superconducting layer.

It is preferable that the intermediate layer includes two or more layers, and has a non-oriented region extending in the longitudinal direction at the end in the width direction of each layer of the intermediate layer.
The intermediate layer includes two or more layers below the orientation region of the oxide superconducting layer, and at least one layer that is a part of the two or more layers constituting the intermediate layer is the oxide superconducting layer. It is preferable that it is missing below the non-oriented region.
The width of the non-oriented region at the end in the width direction of the oxide superconducting layer is preferably in the range of 0.1 to 100 μm over the longitudinal direction.
It is preferable to have a stabilization layer on the outer periphery of the superconducting laminate.

  Further, the present invention is a method for producing the oxide superconducting wire, wherein an intermediate layer and an oxide superconducting layer are laminated in this order on one surface of a metal substrate, and at least the oxide superconducting layer In the laminate having a protective layer covering the surface and wider than the oxide superconducting wire, a laminate having a non-oriented region extending in the longitudinal direction is prepared at least in the intermediate portion in the width direction of the oxide superconducting layer. Cutting the laminated body in the longitudinal direction at a position having the non-oriented region, and the superconducting laminated body having a non-oriented region extending in the longitudinal direction at least at the end in the width direction of the oxide superconducting layer. And a manufacturing method of an oxide superconducting wire characterized by comprising the steps of:

  The step of preparing a laminate having a non-oriented region extending in the longitudinal direction at least in the intermediate portion in the width direction of the oxide superconducting layer, the step of forming the intermediate layer on the metal substrate, and the step of the metal substrate A step of forming an alignment-inhibiting region extending in the longitudinal direction in one surface or an intermediate portion in the width direction of at least one layer constituting the intermediate layer, and the non-oriented region corresponding to the alignment-inhibiting region It is preferable to include a step of forming an oxide superconducting layer on the intermediate layer and a step of forming the protective layer on the oxide superconducting layer.

After forming at least one layer constituting the intermediate layer on the metal substrate, performing the step of forming the alignment inhibition region, and after forming the alignment inhibition region, the oxide on the intermediate layer A step of forming a superconducting layer can be performed.
Prior to the step of forming the intermediate layer on the metal substrate, it is possible to have a step of forming an alignment-inhibiting region extending in the longitudinal direction at the intermediate portion in the width direction of the one surface of the metal substrate. .

  According to the oxide superconducting wire of the present invention, the oxide superconducting layer has a non-oriented region extending in the longitudinal direction at the end in the width direction of the oxide superconducting layer. Can be suppressed.

  According to the method for producing an oxide superconducting wire of the present invention, a superconducting laminate is produced by cutting a laminate having a non-oriented region in the middle in the width direction of the oxide superconducting layer in the longitudinal direction. Damage to the superconducting layer such as cracks can be suppressed.

It is sectional drawing showing 1st Embodiment of the laminated body which has a non-orientation area | region in an intermediate part. It is sectional drawing showing 1st Embodiment of the oxide superconducting wire of this invention. It is sectional drawing showing 2nd Embodiment of the laminated body which has a non-orientation area | region in an intermediate part. It is sectional drawing showing 2nd Embodiment of the oxide superconducting wire of this invention. It is sectional drawing showing 3rd Embodiment of the laminated body which has a non-orientation area | region in an intermediate part. It is sectional drawing showing 3rd Embodiment of the oxide superconducting wire of this invention.

  Hereinafter, based on a preferred embodiment, the present invention will be described with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size. The dimensions and ratios of each component are appropriately changed from the actual ones. Further, the present invention is not limited to the following embodiment.

<First Embodiment>
FIG. 1 shows a first embodiment of a laminate having a non-oriented region in the middle in the width direction. FIG. 2 shows a first embodiment of an oxide superconducting wire having an end non-oriented region in the width direction. A laminated body 5 shown in FIG. 1 and a superconducting laminated body 6 shown in FIG. 2 have an intermediate layer 2 (underlying layer 2A, alignment layer 2B, cap layer 2C), oxide superconducting layer 3 on the main surface 1b of the metal substrate 1. And the protective layer 4 has the laminated structure laminated | stacked in this order. In the intermediate layer 2 and the oxide superconducting layer 3, non-oriented regions 2b and 3b are formed.

  Note that in this specification, the non-oriented region means a region which does not show orientation in a layer including a region where a crystal shows orientation. The orientation-inhibiting region is a region that inhibits the crystal orientation of the layer laminated thereon. Note that the orientation-inhibiting region can also inhibit the orientation of a layer laminated through another layer.

  In the laminate 5 shown in FIG. 1, a concave groove 2Ba reaching the inside of the intermediate layer 2 or the metal substrate 1 is formed on the main surface 2Bb of the alignment layer 2B constituting the intermediate layer 2. On the metal substrate 1, a plurality of concave groove portions 2Ba extend in parallel at intervals. Examples of the method for forming the concave groove 2Ba include a method of moving the metal substrate 1 by pressing a processing tool against the main surface 2Bb of the alignment layer 2B.

  By forming the groove 2Ba on the main surface 2Bb of the alignment layer 2B, the orientation of the alignment layer 2B located immediately below and around the groove 2Ba is disturbed, and a non-alignment region is formed in the alignment layer 2B. . On the edge (both sides in the width direction) of the concave groove 2Ba, a raised portion where the alignment layer 2B is raised may be formed. Therefore, the alignment layer 2B does not have orientation in the recessed groove portion 2Ba and the raised portion, and the region where the recessed groove portion 2Ba or the raised portion is formed functions as a non-oriented region. In addition, the recessed groove 2Ba and the raised portion function as an alignment inhibition region that inhibits the orientation of the cap layer 2C and the oxide superconducting layer 3 laminated thereon.

  The width W1 of the concave groove 2Ba is preferably 0.3 μm or more and 40 μm or less. By setting the width W1 of the concave groove 2Ba to 0.3 μm or more, the non-oriented region 3b can be reliably formed in the oxide superconducting layer 3. In addition, by setting the width W1 of the recessed groove portion 2Ba to 40 μm or less, the width of the non-oriented region 3b of the oxide superconducting layer 3 can be narrowed to increase the critical current density.

  In the present specification, the concave groove 2Ba means a region where the alignment layer 2B is recessed from the main surface 2Bb and is thinner than the film thickness. Further, the raised portion means a region where the alignment layer 2B protrudes from the main surface 2Bb. The depth D1 of the recessed groove portion 2Ba is a distance in the depth direction from the main surface 2Bb of the alignment layer 2B to the deepest portion of the recessed groove portion 2Ba.

  The depth D1 of the groove 2Ba is preferably 0.3 μm or more and 10 μm or less. By setting the depth D1 of the recessed groove 2Ba to 0.3 μm or more, the non-oriented region 3b can be more reliably formed in the oxide superconducting layer 3. Moreover, the strength reduction of the metal substrate 1 can be suppressed by setting the depth D1 of the groove 2Ba to 10 μm or less. Note that the cross-sectional shape of the concave groove 2Ba is not limited to the substantially arc shape shown in FIG. 1, and may be a V-shaped groove, for example.

  Of the cap layer 2C, the portion of the alignment layer 2B laminated on the concave groove 2Ba or the raised portion does not have orientation. Therefore, the intermediate layer 2 has a non-oriented region 2b as a whole in the thickness direction of the recessed groove portion 2Ba or the raised portion.

  Since the orientation of the oxide superconducting layer 3 is controlled by the intermediate layer 2 (particularly the orientation layer 2B and the cap layer 2C), the portion formed on the non-orientation region 2b of the intermediate layer 2 has orientation. I can't. In the oxide superconducting layer 3, a portion formed on the non-oriented region 2b of the intermediate layer 2 becomes a non-oriented region 3b having no orientation.

  Since the non-oriented region 3b of the oxide superconducting layer 3 does not have superconducting characteristics or has a remarkably low critical current, it becomes a high resistance region during use, and current does not easily flow. A region where the intermediate layer 2 and the oxide superconducting layer 3 are formed in parallel to the main surface 1b of the metal substrate 1 becomes an alignment region 10 in which the intermediate layer 2 and the oxide superconducting layer 3 have orientation.

  As illustrated in FIG. 1, the stacked body 5 according to the first embodiment includes non-oriented regions 2 b and 3 b in the intermediate portion in the width direction of the stacked body 5. These non-oriented regions 2 b and 3 b extend in the longitudinal direction of the oriented region 10. When the laminated body 5 is cut in the longitudinal direction at a position where the laminated body 5 has the non-oriented regions 2b and 3b, as shown in FIG. 2, the superconducting laminated body 6 having the non-oriented regions 2b and 3b at the ends in the width direction. Can be produced. This superconducting laminate 6 can be used as an oxide superconducting wire. The oxide superconducting wire may have a stabilization layer around the superconducting laminate 6.

  In the stacked body 5 according to the first embodiment, a part of the intermediate layer 2 that controls the orientation of the oxide superconducting layer 3 is directly processed to form the concave groove 2Ba. Thereby, the non-oriented region 2b can be formed in the intermediate layer 2 more reliably.

  In the oxide superconducting wire including the superconducting laminate 6 according to the present embodiment, even after the oxide superconducting layer 3 is laminated and the laminate 5 is cut, damage such as cracks is caused in the non-oriented regions 2b and 3b. The influence on the alignment region 10 can be suppressed. For this reason, the superconducting property of the oxide superconducting layer 3 in the alignment region 10 does not deteriorate. Further, the peel resistance (peel strength) of each layer in the alignment region 10 does not deteriorate.

  When the oxide superconducting layer is oriented over the entire width direction of the wire, if a defect such as a microcrack occurs due to fine wire processing, the oxide superconducting layer There is a risk that most or the entire surface in the width direction peels off. However, when a non-oriented region is provided at the end in the width direction, since there are many crystal grain boundaries in the non-oriented region of the oxide superconducting layer, the progress of delamination is hindered even if defects such as cracks occur. , Peeling resistance can be improved.

  In general, it is known that the oxide superconducting layer 3 formed by stacking is weak in peeling resistance with respect to a layer located under the oxide superconducting layer 3. According to the oxide superconducting wire according to this embodiment, it is possible to improve the peeling resistance between the oxide superconducting layer 3 and the intermediate layer 2 positioned under the oxide superconducting layer 3 and to suppress the peeling of the oxide superconducting layer 3. . The concave groove 2Ba of the alignment layer 2B is formed by pressing a processing tool against the main surface 2Bb of the alignment layer 2B, and fine irregularities due to processing are formed on the surface. In the cap layer 2C formed on the recessed groove portion 2Ba having the unevenness, fine unevenness is formed on the surface of the cap layer 2C following the fine unevenness formed in the alignment layer 2B. When the oxide superconducting layer 3 is formed on the cap layer 2C, the bonding strength between the cap layer 2C and the oxide superconducting layer 3 is increased due to the anchor effect caused by fine irregularities. Peelability increases. Thereby, it is considered that the oxide superconducting layer 3 is difficult to peel off.

In addition, this embodiment is an example of the structure which forms the ditch | groove part 2Ba in the orientation layer 2B among the intermediate | middle layers 2. FIG. That is, after any one of a plurality of layers constituting the intermediate layer 2 is laminated, an alignment inhibition region is formed along the length direction of the wire on the main surface of the laminated layers. The recessed groove portion formed in the intermediate layer 2 can be formed on the main surface of any one of the plurality of layers constituting the intermediate layer 2 (stacked layer). The non-oriented region 2b can be formed in the intermediate layer 2 by the recessed groove portion. That is, the non-orientation region 2b of the intermediate layer 2 may be a region in which the orientation is disturbed by the concave groove formed in any one of the plurality of layers constituting the intermediate layer 2.
When one or more of the plurality of layers constituting the intermediate layer 2 are at least partially missing in the groove 2Ba, the orientation-inhibiting region is easily formed by removing any of the layers, and the oxide The non-oriented region 3b of the superconducting layer 3 can be more reliably formed.

Further, as illustrated in the present embodiment, by forming the groove 2Ba in the alignment layer 2B, the groove 2Ba is covered with the cap layer 2C formed on the alignment layer 2B. When forming the groove 2Ba in the alignment layer 2B, each layer of the alignment layer 2B, which is a portion located in the groove 2Ba, and the underlying layer 2A located under the portion is thinned or partially removed, The metal substrate 1 is exposed. By forming the cap layer 2C also on the concave groove portion 2Ba, the metal substrate 1 and the oxide superconducting layer 3 are not in direct contact within the region of the concave groove portion 2Ba. Thereby, it can suppress that the metal material which comprises the metal substrate 1 diffuses into the oxide superconducting layer 3. FIG. Therefore, it is preferable that the groove 2Ba is formed in the alignment layer 2B and the groove 2Ba is covered with the cap layer 2C.
In the present embodiment, when both the base layer 2A and the alignment layer 2B are at least partially missing in the concave groove 2Ba, the cap layer 2C can have a portion in direct contact with the metal substrate 1. In order to prevent the metal substrate 1 and the oxide superconducting layer 3 from coming into direct contact with each other in the non-oriented region, the missing portion is part of the intermediate layer 2, and either one of the plurality of layers constituting the intermediate layer 2 or 2 More than one layer is preferably interposed between the metal substrate 1 and the oxide superconducting layer 3.

Second Embodiment
FIG. 3 shows a second embodiment of a laminate having a non-oriented region in the middle in the width direction. FIG. 4 shows a second embodiment of an oxide superconducting wire having an end non-oriented region in the width direction. The laminate 15 shown in FIG. 3 and the superconducting laminate 16 shown in FIG. 4 have an intermediate layer 12 (underlayer 12A, alignment layer 12B, cap layer 12C), oxide superconducting layer 13 on the main surface 11b of the metal substrate 11. And the protective layer 14 has a laminated structure laminated in this order. In the intermediate layer 12 and the oxide superconducting layer 13, non-oriented regions 12b and 13b are formed.

  The oxide superconducting wire according to the second embodiment is different from the oxide superconducting wire according to the first embodiment in that the groove portion is formed on the main surface of the metal substrate. The other parts can be generally the same as in the first embodiment.

  In the laminate 15 shown in FIG. 3, the main surface 11 b of the metal substrate 11 is formed with a plurality of concave grooves 11 a that are arranged in parallel at intervals. The recessed groove portion 11 a is a groove formed in the main surface 11 b of the metal substrate 11 and extends in the longitudinal direction of the metal substrate 11. As a method of forming the concave groove portion 11a, a method of moving the metal substrate 11 by pressing a processing tool against the main surface 11b of the metal substrate 11 can be cited.

  The concave groove portion 11a of the metal substrate 11 functions as an alignment inhibition region. That is, the orientation of the intermediate layer 12 and the oxide superconducting layer 13 formed on the groove 11a is hindered, and the intermediate layer 12 and the oxide superconducting layer 13 formed on the groove 11a are not aligned in the non-oriented regions 12b and 13b. Is formed.

  The width W2 of the groove 11a of the metal substrate 11 is preferably 10 μm or more and 500 μm or less. By setting the width W2 of the concave groove portion 11a to 10 μm or more, the non-oriented region 12b having a sufficient width in the intermediate layer 12 can be formed. In addition, by setting the width W2 of the recessed groove portion 11a to 500 μm or less, the width of the non-oriented region 13b of the oxide superconducting layer 13 can be narrowed to increase the critical current density.

  The depth D2 of the concave groove portion 11a of the metal substrate 11 is preferably 0.3 μm or more and 10 μm or less. By setting the depth D2 of the concave groove portion 11a to 0.3 μm or more, the non-oriented region 12b can be more reliably formed in the intermediate layer 12. Moreover, the strength reduction of the metal substrate 11 can be suppressed by setting the depth D2 of the concave groove portion 11a to 10 μm or less. In addition, the cross-sectional shape of the recessed groove part 11a is not limited to the V shape shown in FIG. 3, and may be a substantially arc-shaped groove, for example.

  In this embodiment, since the inclined surface by the groove 11a is formed on the metal substrate 11, the orientation of the intermediate layer 12 formed on the groove 11a is disturbed. Thereby, in the intermediate layer 12, a non-oriented region 12b corresponding to the groove 11a is formed in a portion formed on the groove 11a of the metal substrate 11. Moreover, the groove part 12a corresponding to the shape of the groove part 11a is formed in the surface of the intermediate | middle layer 12 formed on the groove part 11a. In addition, the cross-sectional shape of the concave groove portion 12a of the intermediate layer 12 is not limited to the V shape shown in FIG. 3, and may be a substantially arc-shaped groove, for example.

  The orientation of the oxide superconducting layer 13 is controlled by the intermediate layer 12 (particularly, the orientation layer 12B and the cap layer 12C). Therefore, the portion formed on the non-oriented region 12b of the intermediate layer 12 does not have sufficient orientation to develop a superconducting state. In the oxide superconducting layer 13, the portion formed on the non-oriented region 12b of the intermediate layer 12 becomes a non-oriented region 13b in which the crystal orientation is disturbed. Further, in this non-oriented region 13b, a groove 13a corresponding to the groove 12a of the intermediate layer 12 is formed. Note that the cross-sectional shape of the concave groove portion 13a of the oxide superconducting layer 13 is not limited to the V shape shown in FIG. 3, and may be a substantially arc-shaped groove, for example.

  The orientation of the oxide superconducting layer 13 depends not only on the orientation of the intermediate layer 12 but also on the surface properties of the intermediate layer 12. Oxide superconductivity formed on the groove 12a and the non-oriented region 12b by providing the intermediate layer 12 with the non-oriented region 12b and forming the groove 12a on the surface of the intermediate layer 12. The crystals constituting the layer 13 are less likely to be oriented, and the non-orientation of the non-orientation region 13b becomes remarkable.

  The non-oriented region 13b of the oxide superconducting layer 13 does not have superconducting properties or has a remarkably low critical current, so that it becomes a high resistance region during use, and current does not flow easily. A region where the intermediate layer 12 and the oxide superconducting layer 13 are formed in parallel to the main surface 11b of the metal substrate 11 becomes an alignment region 20 in which the intermediate layer 12 and the oxide superconducting layer 13 have orientation. A groove 14 a corresponding to the shape of the groove 13 a may be formed on the surface of the protective layer 14 formed on the groove 13 a of the oxide superconducting layer 13.

  As illustrated in FIG. 3, the stacked body 15 according to the second embodiment includes non-oriented regions 12 b and 13 b in the intermediate portion in the width direction of the stacked body 15. These non-oriented regions 12 b and 13 b extend in the longitudinal direction of the oriented region 20. When the laminate 15 is cut in the longitudinal direction at the position where the laminate 15 has the non-oriented regions 12b and 13b, as shown in FIG. 4, the superconducting laminate 16 having the non-oriented regions 12b and 13b at the end portions in the width direction. Can be produced. This superconducting laminate 16 can be used as an oxide superconducting wire. The oxide superconducting wire may have a stabilization layer around the superconducting laminate 16.

  In the laminate 15 according to the second embodiment, a part of the metal substrate 11 is directly processed to form the groove 11a. For this reason, the method of forming the intermediate layer 12 and the oxide superconducting layer 13 on the main surface 11b of the metal substrate 11 having the groove 11a may be a conventionally known method. The layers constituting the intermediate layer 12 and the oxide superconducting layer 13 are laminated on the groove 11a of the metal substrate 11 to form the non-oriented regions 12b and 13b.

  In the oxide superconducting wire including the superconducting laminate 16 according to the present embodiment, even after the oxide superconducting layer 13 is laminated and the laminate 15 is cut, damage such as cracks is caused in the non-oriented regions 12b and 13b. The influence on the alignment region 20 can be suppressed. For this reason, the superconducting property of the oxide superconducting layer 13 in the alignment region 20 does not deteriorate. Further, the peel resistance (peel strength) of each layer in the alignment region 20 does not deteriorate.

<Third Embodiment>
FIG. 5 shows a third embodiment of a laminate having a non-oriented region in the middle in the width direction. FIG. 6 shows a third embodiment of an oxide superconducting wire having an end non-oriented region in the width direction. The laminated body 25 shown in FIG. 5 and the superconducting laminated body 26 shown in FIG. 6 have an intermediate layer 22 (underlayer 22A, alignment layer 22B, cap layer 22C), oxide superconducting layer 23 on the main surface 21b of the metal substrate 21. And the protective layer 24 has a laminated structure laminated in this order. In the intermediate layer 22 and the oxide superconducting layer 23, non-oriented regions 22b and 23b are formed.

  The oxide superconducting wire according to the third embodiment is different from the oxide superconducting wire according to the second embodiment in the configuration of the alignment inhibition region. Specifically, rough surface portions 21a and 22a are provided instead of the concave groove portions 11a, 12a and 13a of the second embodiment. The other parts can be generally the same as in the second embodiment.

  In the laminated body 25 shown in FIG. 5, a plurality of rough surface portions 21 a are formed on the main surface 21 b of the metal substrate 21 so as to be spaced in parallel. Examples of the method of forming the rough surface portion 21a include laser irradiation on the main surface 21b of the metal substrate 21. The rough surface portion 21a of the metal substrate 21 is preferably a region having an arithmetic surface roughness Ra of 5 nm to 1000 nm. The arithmetic average roughness Ra of the main surface 21b of the metal substrate 21 is preferably in the range of 3 nm to 4 nm.

  The width W3 of the rough surface portion 21a of the metal substrate 21 is preferably 10 μm or more and 500 μm or less. By setting the width W3 of the rough surface portion 21a to 10 μm or more, the non-oriented region 22b having a sufficient width in the intermediate layer 22 can be formed. Further, by setting the width W3 of the rough surface portion 21a to 500 μm or less, the width of the non-oriented region 23b of the oxide superconducting layer 23 can be narrowed to increase the critical current density.

  In the present embodiment, since the rough surface portion 21a is formed on the metal substrate 21, the orientation of the intermediate layer 22 formed on the rough surface portion 21a is disturbed. Thereby, in the intermediate layer 22, a non-oriented region 22b corresponding to the rough surface portion 21a is formed in a portion formed on the rough surface portion 21a of the metal substrate 21. Since the orientation of the intermediate layer 22 depends on the surface properties of the metal substrate 21 existing under the intermediate layer 22, the rough surface portion 21a of the metal substrate 21 functions as an orientation-inhibiting region. A rough surface portion 22a corresponding to the rough surface portion 21a is formed on the surface of the intermediate layer 22 formed on the rough surface portion 21a.

  The orientation of the oxide superconducting layer 23 is controlled by the intermediate layer 22 (particularly the orientation layer 22B and the cap layer 22C). Therefore, the portion formed on the non-orientation region 22b of the intermediate layer 22 does not have sufficient orientation to develop a superconducting state. In addition, a rough surface portion 22 a is formed on the surface of the non-oriented region 22 b of the intermediate layer 22. Therefore, the oxide superconducting layer 23 formed on the non-oriented region 22b becomes the non-oriented region 23b.

  The non-oriented region 23b of the oxide superconducting layer 23 does not have superconducting characteristics or has a remarkably low critical current, so that it becomes a high resistance region during use, and current does not easily flow. A region where the intermediate layer 22 and the oxide superconducting layer 23 are formed in parallel to the main surface 21b of the metal substrate 21 becomes an alignment region 30 in which the intermediate layer 22 and the oxide superconducting layer 23 have orientation.

  As illustrated in FIG. 5, the stacked body 25 according to the third embodiment includes non-oriented regions 22 b and 23 b in the intermediate portion of the stacked body 25 in the width direction. These non-oriented regions 22 b and 23 b extend in the longitudinal direction of the oriented region 30. When the laminate 25 is cut in the longitudinal direction at the position where the laminate 25 has the non-oriented regions 22b and 23b, as shown in FIG. 6, the superconducting laminate 26 having the non-oriented regions 22b and 23b at the ends in the width direction. Can be produced. The superconducting laminate 26 can be used as an oxide superconducting wire. The oxide superconducting wire may have a stabilization layer around the superconducting laminate 26.

  In the oxide superconducting wire including the superconducting laminate 26 according to the present embodiment, even after the oxide superconducting layer 23 is laminated and the laminate 25 is cut, damage such as cracks is caused in the non-oriented regions 22b and 23b. The influence on the alignment region 30 can be suppressed. For this reason, the superconducting property of the oxide superconducting layer 23 in the alignment region 30 does not deteriorate. Further, the peel resistance (peel strength) of each layer in the alignment region 30 does not deteriorate.

<Oxide superconducting wire>
Hereinafter, the structure of each part which forms an oxide superconducting wire is demonstrated in detail.

  As long as the metal substrates 1, 11, and 21 are substrates (base materials) that can be used for superconducting wires, the type of the metal substrate is not limited. The metal substrate is preferably formed of a metal having heat resistance. As a material for the metal substrate, among heat resistant metals, an alloy is preferable, and a nickel (Ni) alloy or a copper (Cu) alloy is more preferable. Especially, if it is a commercial item, Hastelloy (registered trademark) is suitable, and the amount of components such as molybdenum (Mo), chromium (Cr), iron (Fe), cobalt (Co) is different, Hastelloy B, C, Any kind of G, N, W, etc. can be used. Further, as the metal substrate, an alignment substrate in which the alignment of metal crystals is uniform may be used. In the present embodiment, the shape of the metal substrate is a long tape shape, but may be a sheet shape, for example. What is necessary is just to adjust the thickness of a metal substrate suitably according to the objective, and it can be set as the range of 10-500 micrometers.

  The intermediate layers 2, 12, 22 are formed on the main surfaces 1b, 11b, 21b of the metal substrates 1, 11, 21. As the structure of the intermediate layers 2, 12, and 22, a structure in which the base layers 2A, 12A, and 22A, the alignment layers 2B, 12B, and 22B, and the cap layers 2C, 12C, and 22C are stacked in this order can be applied. . The underlayer can be composed of one or both of a diffusion prevention layer and a bed layer.

When a metal substrate or other layer receives a thermal history as a result of heat treatment when forming another layer (a layer different from the diffusion prevention layer) on the upper surface of the diffusion prevention layer, the diffusion prevention layer is a metal substrate. A part of the constituent elements is diffused and has a function of suppressing entry into the oxide superconducting layer as impurities. The diffusion prevention layer is made of Si ₃ N ₄ , Al ₂ O ₃ , GZO (Gd ₂ Zr ₂ O ₇ ) or the like. The thickness of the diffusion preventing layer is, for example, 10 to 400 nm.

The bed layer is provided in order to suppress the reaction of constituent elements at the interface between the metal substrate and the oxide superconducting layer and to improve the orientation of the layer provided above the bed layer (upper surface of the bed layer). Examples of the material of the bed layer include Y ₂ O ₃ , CeO ₂ , Dy ₂ O ₃ , Er ₂ O ₃ , Eu ₂ O ₃ , Ho ₂ O ₃ , La ₂ O _{3 and the} like. The thickness of the bed layer is, for example, 10 to 100 nm.

The orientation layer is formed from a biaxially oriented material in order to control the crystal orientation of the cap layer thereon. Examples of the material of the alignment layer include Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , Examples thereof include metal oxides such as Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ . This alignment layer is preferably formed by an IBAD (Ion-Beam-Assisted Deposition) method.

The cap layer is formed on the surface of the above-described alignment layer, and is made of a material that allows crystal grains to self-align in the in-plane direction. The material of the cap layer, for _{example, CeO 2, Y 2 O 3} , Al 2 O 3, Gd 2 O 3, ZrO 2, YSZ, Ho 2 O 3, Nd 2 O 3, LaMnO 3 , and the like. Examples of the thickness of the cap layer include a range of 50 to 5000 nm.

The oxide superconducting layers 3, 13, and 23 are made of an oxide superconductor. The oxide superconductor is not particularly limited, for example, the general formula _{REBa 2 Cu 3 O X (RE123} ) with rare earth-based oxide superconductor represented the like. Examples of the rare earth element RE include one or more of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. It is done. Among these, one of Y, Gd, Eu, and Sm, or a combination of two or more of these elements is preferable. The thickness of the superconducting layer is, for example, about 0.5 to 5 μm. This thickness is preferably uniform in the longitudinal direction. The oxide superconducting layer is deposited by sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, physical vapor deposition such as chemical vapor deposition (CVD), thermal coating decomposition (MOD), or the like. be able to.

  The protective layers 4, 14, and 24 suppress the chemical reaction that occurs between an oxide superconducting layer and a layer (for example, a stabilization layer) provided on the protective layer, bypassing overcurrent generated in the event of an accident. It has a function such as. Examples of the material of the protective layer include metals such as silver (Ag), copper (Cu), gold (Au), alloys of gold and silver, other silver alloys, copper alloys, and gold alloys. The protective layer covers at least the surface of the oxide superconducting layer (the surface opposite to the metal substrate side in the thickness direction). Further, the protective layer may cover part or all of the region selected from the side surface of the oxide superconducting layer, the side surface of the intermediate layer, the side surface and the back surface of the metal substrate.

  As thickness of a protective layer, about 1-30 micrometers is mentioned, for example. When the oxide superconducting layer has a non-planar surface shape in the non-oriented region of the oxide superconducting layer, the protective layer may have a non-flat surface shape as well, and the protective layer so that the surface of the protective layer is flat. The thickness may be distributed. When the protective layer is thinly formed by sputtering, vapor deposition, or the like, and a groove (for example, the groove 14a in FIG. 3) is formed on the surface of the protective layer on the non-oriented region of the oxide superconducting layer, the protective layer extends along the non-oriented region. This is preferable because the laminate can be easily cut.

  In the above-described embodiment, the oxide superconducting layer of the superconducting laminate is divided from the outside in the width direction by the non-oriented regions at both ends in the width direction. Since the protective layer covering the surface of the oxide superconducting layer has conductivity, the oxide superconducting layer can be electrically connected to the outside (such as a stabilization layer). When oxygen annealing of the oxide superconducting layer is performed after or before cutting the laminate, it is preferable to form the protective layer under conditions that allow oxygen gas to pass through the protective layer and reach the oxide superconducting layer during annealing. .

  When producing the superconducting laminates 6, 16, and 26 by cutting the laminates 5, 15, and 25 having the non-oriented regions in the intermediate portion in the width direction, the cutting method includes a continuous wave or pulsed laser beam. It is done. The laser is not particularly limited, and examples thereof include an optical fiber laser using a rare earth-doped optical fiber, a solid laser, and a gas laser. From the viewpoint of productivity, a continuous wave optical fiber laser is preferable.

  The spot diameter of the laser beam is, for example, about 20 μm, and is preferably 500 μm or less, 100 μm or less, and 10 μm or more. The laminated structure when the laminated body is cut preferably includes a metal substrate, an intermediate layer, an oxide superconducting layer, a protective layer, and no stabilizing layer, metal tape, or the like. The width of the cut part from which a part of the laminate is removed is preferably 100 μm or less. Moreover, it is preferable that the width | variety of a cut part is narrower than the width | variety of the non-orientation area | region provided in the intermediate part of the width direction of the laminated body before cutting | disconnection.

  When a part of the laminate is melted by cutting and an amorphous melt is generated, it is preferable to blow off the melt from the laminate by spraying a shielding gas such as an inert gas. The center wavelength of the laser is preferably in the near infrared region, for example, a wavelength of about 1050 to 1100 nm. The laser beam output is preferably about 10 W to 1 kW, for example, although it depends on the material and thickness of the laminate.

  The method for controlling the cutting position of the laminated body is not particularly limited, but a method for numerically controlling the distance from the reference to the cutting position by providing a reference (line or point) on the metal substrate or the like, or a cutting position on the metal substrate or the like. And a method of providing marks on both ends in the longitudinal direction. The width (per one side) of the non-oriented region remaining at the end in the width direction of the superconducting laminate after cutting is preferably about 0.1 to 100 μm, or about 0.3 to 50 μm. If the width of the non-oriented region is too wide, the width of the oriented region is narrow and the critical current density may be reduced. If the width of the non-oriented region is too narrow, the effect of suppressing peeling is reduced. The number and positions of the non-oriented regions and the cut portions in the width direction of the laminate are not particularly limited, but may be two or more at equal intervals or at arbitrary intervals.

  Regarding the laminated structure of the intermediate layer, as described in the first embodiment, at least one or two or more layers (for example, an underlayer or an alignment layer) constituting the intermediate layer in the non-oriented region at the end in the width direction of the superconducting laminate. Constituting the layer) may be missing. It is preferable that at least one or two or more layers constituting the intermediate layer are laminated under the oxide superconducting layer continuously from the oriented region to the non-oriented region. The layer that continues from the oriented region to the non-oriented region preferably includes a layer (for example, a cap layer) in contact with the oxide superconducting layer in the oriented region. It is preferable that the layer missing at the end in the width direction of the intermediate layer is one or more of the layers stacked below the cap layer. In this case, since at least one layer exists continuously from the alignment region between the missing layer in the non-alignment region and the oxide superconducting layer, it is between the alignment region and the non-alignment region of the oxide superconducting layer. The discontinuity which arises can be relieved and it is preferable.

  Regarding the manufacturing method, when the intermediate layer is composed of two or more layers, the step of forming the alignment inhibition region first may be a step of forming the alignment inhibition region on the metal substrate before the intermediate layer is laminated. It may be after laminating one or more layers, or after laminating all the layers constituting the intermediate layer. As described in the first embodiment, an alignment-inhibiting region is formed after a part of layers (for example, an alignment layer) constituting the intermediate layer is stacked, and then the remaining layer (for example, a cap layer) that further forms the intermediate layer. You may have the process of laminating | stacking. In this case, since the remaining layer constituting the intermediate layer is interposed between the alignment inhibition region initially formed in a part of the layers constituting the intermediate layer and the oxide superconducting layer, the orientation of the oxide superconducting layer is The discontinuity generated between the region and the non-oriented region can be relaxed, which is preferable.

  As a stabilization layer, the structure by which metal layers, such as a metal tape, a plating layer, and a vapor deposition layer, were laminated | stacked on the protective layer may be sufficient. A metal tape may be laminated on a protective layer, a plating layer, a vapor deposition layer, a metal substrate, or the like, or around the superconducting laminate via a bonding material layer such as solder. Two or more kinds of stabilization layers can be laminated. After cutting the laminate, a metal layer similar to the protective layer or the stabilization layer may be laminated on the cut surface.

  As the metal tape, a relatively inexpensive conductive metal material such as copper, a copper alloy such as a Cu—Zn alloy and a Cu—Ni alloy, aluminum or an aluminum alloy, and stainless steel can be used. As the bonding material, for example, Sn-Pb-based, Pb-Sn-Sb-based, Sn-Pb-Bi-based, Bi-Sn-based, Sn-Cu-based, Sn-Pb-Cu-based, Sn-Ag-based solder, Examples thereof include metals such as Sn, Sn alloy, In, In alloy, Zn, Zn alloy, Ga, and Ga alloy. Examples of the plating layer and the vapor deposition layer include Ag, Cu, and alloys thereof.

  The oxide superconducting wire may be further entirely covered with an insulating coating layer. By covering the oxide superconducting wire with the coating layer, the entire oxide superconducting wire is protected, and an oxide superconducting wire with stable performance can be obtained. The coating layer is preferably formed of a known material such as various resins or oxides that are usually used for insulating coating such as oxide superconducting wire.

Specific examples of the resin constituting the coating layer include polyimide resin, polyamide resin, epoxy resin, acrylic resin, phenol resin, melamine resin, polyester resin, silicon resin, silicon resin, alkyd resin, and vinyl resin. Moreover, an ultraviolet curable resin is preferable. As the oxide constituting the coating _{layer, CeO 2, Y 2 O 3} , Gd 2 Zr 2 O 7, Gd 2 O 3, ZrO 2 -Y 2 O 3 (YSZ), Zr 2 O 3, Ho 2 O ₃ etc. can be illustrated.

  When the winding of the tape-shaped superconducting wire is a superconducting coil, it is preferable to impregnate the resin between the wires of the winding. By filling the resin between the wires, the wires are bonded to each other and an electrical short circuit is prevented. Moreover, the superconducting wire can have an external terminal. The portion having the external terminal may have a different cross-sectional structure from other portions.

  As mentioned above, although this invention has been demonstrated based on suitable embodiment, this invention is not limited to the above-mentioned embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  Examples of the alignment inhibition region formed in the metal substrate or intermediate layer include the groove portion of the metal substrate or intermediate layer, the raised portion of the metal substrate or intermediate layer, the rough surface portion of the metal substrate or intermediate layer, and the intermediate layer of the intermediate layer. It is not limited to non-oriented regions. Two or more of these orientation-inhibiting regions can be combined. A raised portion can be formed on the side along with the recessed groove portion, and the raised portion can be formed on the main surface without accompanying the recessed groove portion. The ridges (projections) extending in the longitudinal direction can be formed by applying a material different from that of the metal substrate or the intermediate layer on the main surface of either the metal substrate or the intermediate layer.

  The oxide superconducting wire of the above embodiment has non-oriented regions extending in the longitudinal direction of the oxide superconducting layer and the intermediate layer at both ends in the width direction of the superconducting laminate. Further, in the oxide superconducting wire of the above embodiment, the non-oriented region is provided only at both ends in the width direction of the superconducting laminate, and the intermediate portion in the width direction is an oriented region. In another embodiment, a non-oriented region can also be provided in the middle part of the superconducting laminate. In addition, a non-oriented region provided in the middle part of the superconducting laminate may be provided continuously in the longitudinal direction, thereby providing a multifilament structure in which two or more oriented regions are provided divided in the width direction. it can. The filament width by the alignment region is preferably 100 μm or more.

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not limited only to these Examples.

On a Hastelloy (trade name, Haynes, USA) substrate, an Al ₂ O ₃ diffusion prevention layer (film thickness: 100 nm) was formed by sputtering. Next, a Y ₂ O ₃ bed layer (thickness: 30 nm) was formed on the diffusion prevention layer by ion beam sputtering. Next, an MgO alignment layer (film thickness: 5 to 10 nm) was formed on the bed layer by ion beam assisted vapor deposition (IBAD method). A groove portion was formed by a continuous scratch in the longitudinal direction from the surface of the alignment layer, and the alignment layer in the groove portion was removed. In the groove portion, the underlayer (diffusion prevention layer and bed layer) may be further removed, and the main surface of the metal substrate may be damaged.

A CeO ₂ cap layer (thickness: 500 nm) was formed on the alignment layer by pulsed laser deposition (PLD method). Next, an oxide superconducting layer (film thickness: 2 μm) of GdBa ₂ Cu ₃ O _X was formed on the cap layer by the PLD method. An Ag protective layer was formed on the outer periphery of the laminate including the oxide superconducting layer by sputtering. The protective layer can be formed not only on the surface and the side surface of the oxide superconducting layer, but also on the side surface of the intermediate layer and the metal substrate and the back surface of the metal substrate. Thereafter, fine wire processing was performed by laser cutting along the concave groove formed in the intermediate layer. When the crystal state of the cut surface (surface) of the intermediate layer and the oxide superconducting layer was confirmed on the cut surface of the obtained superconducting wire, it had a non-oriented region due to the groove.

1,11,21 ... Metal substrate, 1b, 11b, 21b ... Main surface (one surface), 2,12,22 ... Intermediate layer, 2A, 12A, 22A ... Underlayer, 2B, 12B, 22B ... Alignment layer, 2C, 12C, 22C ... cap layer, 2b, 12b, 22b ... non-oriented region of intermediate layer, 3, 13, 23 ... oxide superconducting layer, 3b, 13b, 23b ... non-oriented region of oxide superconducting layer, 4, 14, 24 ... protective layer, 5, 15, 25 ... laminate, 6, 16, 26 ... superconducting laminate, 10, 20, 30 ... orientation region.

Claims (9)

An oxide superconducting wire comprising a superconducting laminate in which an intermediate layer and an oxide superconducting layer are laminated in this order on one surface of a metal substrate, and further a protective layer covering at least the surface of the oxide superconducting layer is provided. Because
An oxide superconducting wire characterized by having a non-oriented region extending in the longitudinal direction at an end in the width direction of the oxide superconducting layer.   2. The oxide superconducting wire according to claim 1, wherein the intermediate layer includes two or more layers, and has a non-oriented region extending in a longitudinal direction at an end in a width direction of each layer of the intermediate layer.   The intermediate layer includes two or more layers below the orientation region of the oxide superconducting layer, and at least one layer that is a part of the two or more layers constituting the intermediate layer is the oxide superconducting layer. The oxide superconducting wire according to claim 1, wherein the oxide superconducting wire is missing below the non-oriented region.   The width of the non-oriented region at the end in the width direction of the oxide superconducting layer is in the range of 0.1 to 100 µm over the longitudinal direction. The oxide superconducting wire described.   The oxide superconducting wire according to any one of claims 1 to 4, further comprising a stabilizing layer on an outer periphery of the superconducting laminate. It is a manufacturing method of the oxide superconducting wire given in any 1 paragraph of Claims 1-5,
On one surface of the metal substrate, an intermediate layer and an oxide superconducting layer are laminated in this order, and a protective layer covering at least the surface of the oxide superconducting layer is provided, which is wider than the oxide superconducting wire. In the laminate, a step of preparing a laminate having a non-oriented region extending in the longitudinal direction at least in the intermediate portion in the width direction of the oxide superconducting layer;
The step of cutting the laminate in the longitudinal direction at a position having the non-oriented region and producing the superconducting laminate having a non-oriented region extending in the longitudinal direction at least at the end in the width direction of the oxide superconducting layer. And a method of manufacturing an oxide superconducting wire.   The step of preparing a laminate having a non-oriented region extending in the longitudinal direction at least in the intermediate portion in the width direction of the oxide superconducting layer, the step of forming the intermediate layer on the metal substrate, and the step of the metal substrate A step of forming an alignment-inhibiting region extending in the longitudinal direction in one surface or an intermediate portion in the width direction of at least one layer constituting the intermediate layer, and the non-oriented region corresponding to the alignment-inhibiting region The method for producing an oxide superconducting wire according to claim 6, comprising: forming an oxide superconducting layer on the intermediate layer; and forming the protective layer on the oxide superconducting layer. Method.   After forming at least one layer constituting the intermediate layer on the metal substrate, performing the step of forming the alignment inhibition region, and after forming the alignment inhibition region, the oxide on the intermediate layer The method for producing an oxide superconducting wire according to claim 7, wherein a step of forming a superconducting layer is performed.   Prior to the step of forming the intermediate layer on the metal substrate, the method includes a step of forming an alignment-inhibiting region extending in the longitudinal direction at an intermediate portion in the width direction of the one surface of the metal substrate. The manufacturing method of the oxide superconducting wire of Claim 7.

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