JP5775810B2 - Manufacturing method of oxide superconducting wire - Google Patents

Description

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

The Re-123 oxide superconductor (ReBa ₂ Cu ₃ O _7-X : Re is a rare earth element including Y) exhibits superconductivity at a liquid nitrogen temperature and has a low current loss. A superconducting conductor or a superconducting coil for supplying power has been manufactured. As an example of a structure obtained by processing this oxide superconductor into a wire, an oxide superconducting wire in which an oxide superconducting layer is formed on a base material of a metal tape via an intermediate layer is provided.

At present, a tape-shaped substrate made of Ni alloy called Hastelloy (registered trademark) is applied to the metal tape substrate, and a substrate having high strength and excellent flexibility is provided.
The intermediate layer uses a crystalline ceramic thin film that functions as a buffer layer interposed between a metal substrate and an oxide superconducting layer, and is a crystal called an IBAD method (ion beam assisted deposition method). An intermediate layer having a good crystal orientation is formed by biaxial orientation on a metal substrate by a film forming method using an orientation technique. An intermediate thin film called a cap layer is formed on the intermediate layer, and is laminated for the purpose of excellent crystal orientation and preventing impurity diffusion from the intermediate layer or the substrate side.
The oxide superconducting layer is laminated as a ceramic thin film made of an oxide superconductor typified by ReBa ₂ Cu ₃ O _7-X , and a protective layer mainly made of Ag is formed on the oxide superconducting layer. It is provided for the purpose of protecting the water from moisture. In addition, a stabilizing metal layer made of Cu is laminated on the protective layer, and the oxide superconducting layer is configured to be a current bypass when the oxide superconducting layer receives a disturbance and transitions to a normal conducting state. An insulating layer is provided on the oxide superconducting wire.

Among Re-123 oxide superconductors, it is known that oxide superconductors such as Y-based oxides are affected by moisture to disturb the crystal structure and deteriorate the superconducting properties when exposed to a humid environment. Therefore, it is necessary to protect the oxide superconducting layer from moisture, and for this purpose, an Ag protective layer (stabilizing layer) or the like is formed.
For example, a structure in which an oxide superconducting layer is plated as described in Patent Document 1 or a composite material in which a superconducting tape and a stabilizer tape are sandwiched between solders as described in Patent Document 2 is heated. There is a method of manufacturing by pressing with a pressure roll.

JP 2007-080780 A JP 2009-048987 A

  However, in the structure where the plating process is performed, if there is a defect in the plated portion, moisture enters the superconducting layer from this portion, so that the superconducting characteristics may be deteriorated in a humid environment. Further, in the structure manufactured by stacking solder, since a sufficient stabilization layer is not formed on the side surface, moisture enters the superconducting layer from the side surface, so that the superconducting characteristics may deteriorate in a humid environment.

  The present invention has been made in view of the above-described conventional situation, and the oxide superconducting layer is deteriorated due to the influence of moisture as a structure in which the oxide superconducting layer is wrapped by a stabilization layer obtained by bending the oxide superconducting laminate. It is an object to provide an oxide superconducting conductor and a manufacturing method thereof.

The method of manufacturing an oxide superconducting wire according to claim 1 of the present invention includes an oxide superconducting laminate formed by laminating a tape-like base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order. A tape-shaped stabilization layer having a U-shaped cross section covering the peripheral surface leaving one side surface laminated from the protective layer to the substrate of the oxide superconducting laminate, and protruding outward in the width direction of the oxide superconducting laminate In the extended end portion of each of the tape-shaped stabilization layers, the oxide superconducting laminate is positioned on one side surface and has a diameter corresponding to the height direction of the oxide superconducting laminate in the stacking direction. said oxide superconducting laminate the tape-shaped stabilizing layer bonded to the extending end portion to each other in a stabilizing material thin wire protruding outward in the width direction of Ri Na is sealed is surrounded by, the tape-shaped stabilizer The extended end of the layer and the stabilizer thin wire are joined by solder A method of manufacturing the oxide superconducting wire, wherein the tape-shaped stabilizing layer covers a peripheral surface in a U-shaped cross section leaving one side of the oxide superconducting laminate, and the stabilization Inserting a thin wire into the extended end of each tape-shaped stabilization layer protruding outward in the width direction of the oxide superconducting laminate, and the extending end of the tape-shaped stabilization layer and the stabilizing material And a step of joining the thin wire by heating and pressing, wherein the diameter of the stabilizing material thin wire to be inserted is set to be larger than the height in the stacking direction of the oxide superconducting laminate. .
In the method for producing an oxide superconducting wire according to claim 2 of the present invention, an oxide superconducting laminate formed by laminating a tape-like base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order, A tape-shaped stabilization layer having a U-shaped cross section covering the peripheral surface leaving one side surface laminated from the protective layer to the substrate of the oxide superconducting laminate, and protruding outward in the width direction of the oxide superconducting laminate In the extended end portion of each of the tape-shaped stabilization layers, the oxide superconducting laminate is positioned on one side surface and has a diameter corresponding to the height direction of the oxide superconducting laminate in the stacking direction. said oxide superconducting laminate the tape-shaped stabilizing layer bonded to the extending end portion to each other in a stabilizing material thin wire protruding outward in the width direction of Ri Na is sealed is surrounded by, the tape-shaped stabilizer The extended end of the layer and the stabilizing wire are A method of manufacturing a bonded oxide superconducting wire, the step of covering the circumferential surface in a U-shaped cross section leaving one side of the oxide superconducting laminate with the tape-shaped stabilization layer, and the stabilization Inserting a chemical thin wire into the extending end of each tape-shaped stabilizing layer protruding outward in the width direction of the oxide superconducting laminate, and stabilizing the extending end of the tape-shaped stabilizing layer A step of joining the thin metal wires by laser welding, wherein the diameter of the inserted thin wire for stabilizing material is set to be smaller than the height in the stacking direction of the oxide superconducting laminate .

  In the oxide superconducting wire of the present invention, an oxide superconducting laminate in which a tape-like base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer are laminated in this order is the oxide superconducting laminate. A tape-shaped stabilization layer having a U-shaped cross-section covering the peripheral surface leaving one side surface laminated from the protective layer to the substrate, and each of the tape-shaped stability protruding outward in the width direction of the oxide superconducting laminate The oxide superconducting laminate has a diameter dimension corresponding to a height dimension in the stacking direction of the oxide superconducting laminate and located on one side of the oxide superconducting laminate within the extended end portion of the oxide layer. The stabilizing wire is surrounded and sealed by the stabilizing thin wires joined to the extending ends of the tape-shaped stabilizing layer protruding outward in the width direction. In this oxide superconducting wire, the oxide Three surfaces of the superconducting laminate are taped The also 1 side in Joka layer is sealed by a stabilizing material thin line. Thus, the U-shaped tape-shaped stabilization layer, the extended end portions of the attached stabilization layer, and the stabilizing material thin wire are sealed by bonding at the side position of the oxide superconducting laminate. Therefore, it becomes possible to perform bonding without adversely affecting the oxide superconducting laminate.

In the oxide superconducting wire according to the present invention, the tape-shaped stabilizing layer leaves one side of the oxide superconducting laminate to cover a circumferential surface in a U-shaped cross section, and the stabilizing material thin wire is oxidized. A step of inserting into the extended end portion of each of the tape-shaped stabilization layers protruding outward in the width direction of the superconductor laminate, and heating the extended end portion of the tape-shaped stabilization layer and the stabilizing material thin wire By the manufacturing method having the step of joining by pressurization, the extended end portion of the tape-shaped stabilizing layer and the stabilizing material thin wire can be joined by solder, thereby reducing the number of operations. Further, it is possible to perform sealing while reducing the influence on the oxide superconducting laminate only by heating and pressurizing the extended end portion and the stabilizing material thin wire.
At this time, the diameter of the thin stabilizer wire to be inserted is set to be larger than the height dimension in the stacking direction of the oxide superconducting laminate, so that the extended end portion and the stabilizer thin wire are brought into contact with each other. The joining process can be performed in a state, and the sealing degree in the joining can be further improved.
In the present invention, the diameter dimension of the stabilizer thin wire to be inserted is “larger” than the height dimension in the stacking direction of the oxide superconducting laminate. It means a dimension that can be inserted between the extended end portions as long as the shape can be maintained.

In the oxide superconducting wire according to the present invention, the tape-shaped stabilizing layer leaves one side of the oxide superconducting laminate to cover a circumferential surface in a U-shaped cross section, and the stabilizing material thin wire is oxidized. Laser welding the step of inserting into the extending end of each tape-shaped stabilization layer protruding outward in the width direction of the superconducting laminate, and the extending end of the tape-shaped stabilizing layer and the stabilizing wire The extending end portion of the tape-shaped stabilization layer and the stabilizing material thin wire can be joined by a laser welded portion, thereby reducing the number of operations. By simply joining the extended end portion and the stabilizing material thin wire, it is possible to reliably perform sealing while reducing the influence on the oxide superconducting laminate.
At this time, the diameter of the thin stabilizer wire to be inserted is set to be smaller than the height in the stacking direction of the oxide superconducting laminate, so that it contacts three surfaces of the oxide superconducting laminate during heating and pressurization. It is possible to join the extended end portion and the stabilizing material thin wire without being affected by the solder moving from the surface of the tape-like stabilizing layer or the like, and to further improve the sealing degree in the joining.

  In the present invention, a solder layer is provided on the inner surface side of the stabilizing material thin wire and joined to the peripheral surface of the oxide superconducting laminate, or a solder layer is provided on the inner surface side of the stabilizing tape-shaped stabilization layer. And can be bonded to the peripheral surface of the oxide superconducting laminate.

  According to the present invention, since the periphery of the oxide superconducting laminate is hermetically sealed with the tape-shaped stabilizing layer and the stabilizing material thin wire, the tape-shaped stabilization layer can be obtained simply by processing the tape-shaped stabilizing layer into a U-shaped cross section. Oxide superconducting laminate while reducing the work man-hours by joining without further processing of the extended end part that becomes the U-shape of the layer and reducing the influence on the oxide superconducting laminate during the sealing process It is possible to prevent the deterioration of superconducting characteristics by sealing.

FIG. 1 is a cross-sectional view showing a first embodiment of an oxide superconducting wire according to the present invention. FIG. 2 is a perspective view of a superconducting laminate of the same oxide superconducting wire. FIG. 3 is a cross-sectional view showing the steps of the first embodiment in the method for manufacturing an oxide superconducting wire according to the present invention. FIG. 4 is a flowchart showing the steps of the first embodiment in the method for manufacturing an oxide superconducting wire according to the present invention. FIG. 5 is a cross-sectional view showing a second embodiment of the oxide superconducting wire according to the present invention. FIG. 6 is a cross-sectional view showing the steps of the second embodiment in the method for manufacturing an oxide superconducting wire according to the present invention. FIG. 7 is a cross-sectional view showing a process of another embodiment in the method of manufacturing an oxide superconducting wire according to the present invention. FIG. 8 is a cross-sectional view showing a process of another embodiment in the method for manufacturing an oxide superconducting wire according to the present invention. FIG. 9 is a graph showing an example in the method for producing an oxide superconducting wire according to the present invention.

Hereinafter, a first embodiment of an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an oxide superconducting wire according to this embodiment. In the figure, reference numeral 1 denotes an oxide superconducting wire, and reference numeral 10 denotes a superconducting laminate constituting a part of the oxide superconducting wire 1. FIG. 2 is a perspective view of the superconducting laminate 10, and FIG. 3 is a cross-sectional view showing the steps of the method for manufacturing an oxide superconducting wire according to this embodiment.

  As shown in FIG. 1, the oxide superconducting wire 1 in this embodiment is an oxide formed by laminating a tape-like base material 11, an intermediate layer 14, an oxide superconducting layer 16, and a conductive protective layer 17 in this order. The superconducting laminate 10 is hermetically sealed with its peripheral surface surrounded by a stabilization layer 20.

As shown in FIG. 1, the tape-shaped stabilization layer 20 has a tape-shaped stabilization layer 21 bent in a U-shaped cross section along the peripheral surface of the oxide superconducting laminate 10 and a stabilizing material thin wire 22. doing. A solder layer 23 is formed on the tape-shaped stabilization layer 21 as described later.
As shown in FIG. 3A, the tape-shaped stabilization layer 21 is formed as a flat sheet as a whole with a solder layer 23 disposed on the entire surface on one side which is the inside thereof.
As shown in FIG. 1, the tape-shaped stabilizing layer 21 is bent from the protective layer 17 of the oxide superconducting laminate 10 so that the solder layer 23 is on the inner side in the width direction. 11 is formed in a U-shaped cross section along the oxide superconducting laminate 10, and the width direction of the oxide superconducting laminate 10 is wider than that of the one side 10 a. Extending end portions 21a, 21a extending outward are formed. The extended end portions 21 a and 21 a are extended outward in the width direction into a shape aligned beyond the other surface 10 a of the superconducting laminate 10.

As shown in FIG. 3B, the stabilizer thin wire 22 has a diameter dimension 22t corresponding to the height dimension in the stacking direction of the oxide superconducting laminate 10, and the solder layer 23 is disposed on the entire surface thereof. .
The stabilizing material thin wire 22 is an inner position sandwiched between the extended end portions 21a of the respective tape-shaped stabilization layers 21 protruding outward in the width direction of the oxide superconducting laminate 10 and the oxide superconducting laminate 10. It is arrange | positioned in one side surface 10a side part position.

The metal material constituting the stabilization layer 20 is not particularly limited as long as it has good conductivity, and it is preferable to use a relatively inexpensive material such as Cu. Thereby, it is possible to improve the sealing degree by the stabilization layer 20 while keeping the material cost low. The thickness of the tape-shaped stabilization layer 21 is preferably 20 to 150 μm, and more preferably about 50 μm. As will be described later, the diameter of the stabilizer thin wire 22 is about 10% larger than the height of the oxide superconducting laminate 10 in the stacking direction, and is deformed under pressure with respect to the extended end 21a. And is bonded and closed by the solder layer 23.
The solder layer 23 is made of, for example, tin (Sn), Sn—Pb, Pb—Sn—Sb, Sn—Sb, Sn—Pb—Bi, Bi—Sn, Sn—Cu, Sn—Pb—. It is formed of a Sn alloy such as Cu, Sn—In, Sn—Ag, or Sn—Pb—Ag, and the thickness is preferably 2 to 10 μm, and more preferably about 6 μm.

  As shown in FIG. 2, the superconducting laminate 10 of this embodiment has a diffusion prevention layer 12, a bed layer 13, an intermediate layer 14, a cap layer 15, and an oxide superconducting layer 16 on a tape-like metal substrate 11. The protective layer 17 is laminated in this order.

  The metal substrate 11 applicable to the superconducting laminate 10 of the present embodiment can be used as a substrate of a normal superconducting laminate, has only to have high strength and certain flexibility, and is a tape for making a long cable. It is preferably in the form of a heat-resistant metal. For example, various metal materials such as nickel alloys such as stainless steel and Hastelloy (registered trademark, trade name manufactured by Haynes, USA), or ceramics disposed on these various metal materials can be used. Among various heat resistant metals, nickel alloys are preferable. Especially, if it is a commercial item, Hastelloy is suitable, and any kind of Hastelloy B, C, G, N, W, etc. which have different amounts of components such as molybdenum, chromium, iron and cobalt can be used as Hastelloy. . What is necessary is just to adjust the thickness of the metal base material 11 suitably according to the objective, and it is 10-500 micrometers normally. An oriented Ni—W alloy base material in which a texture is introduced into a nickel alloy can also be applied as the metal base material 11.

The bed layer 13 has high heat resistance and is used for reducing interfacial reactivity, and is used for obtaining the orientation of a film disposed thereon. Such a bed layer 13 is arranged according to need, for example, Er 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 . A single-layer structure or a multi-layer structure made of a material made of the rare earth oxide shown. The bed layer 13 has a thickness of 10 to 200 nm, for example.
In the present embodiment, the diffusion prevention layer 12 is interposed between the metal substrate 11 and the bed layer 13, but the diffusion prevention layer 12 is not an essential configuration. The diffusion prevention layer 12 is formed for the purpose of preventing the constituent elements of the metal substrate 11 from diffusing. GZO (Gd ₂ Zr ₂ O ₇ ), amorphous aluminum oxide Al ₂ O ₃ , yttria (Y ₂ O ₃ ) , Silicon nitride (Si ₃ N ₄ ), etc., and the thickness thereof is, for example, 10 to 400 nm.

The diffusion preventing layer 12 is interposed between the metal substrate 11 and the bed layer 13 in this way when the other layers such as the intermediate layer 14, the cap layer 15, and the oxide superconducting layer 16 are formed. In order to suppress diffusion of some of the constituent elements of the metal substrate 11 to the oxide superconducting layer 16 side through the bed layer 13 at that time. is there. The element diffusion from the metal substrate 11 side can be effectively suppressed by adopting the two-layer structure of the diffusion prevention layer 12 and the bed layer 13 as in the present embodiment. An example of the case where the diffusion preventing layer 12 is interposed between the metal substrate 11 and the bed layer 13 includes a combination using Al ₂ O ₃ as the diffusion preventing layer 12 and Y ₂ O ₃ as the bed layer 13. it can.

The intermediate layer 14 may have either a single layer structure or a multilayer structure, and is selected from materials that are biaxially oriented in order to control the crystal orientation of the oxide superconducting layer 16 laminated thereon. Specifically, preferred materials for the intermediate layer 14 are Gd ₂ Zr ₂ O ₇ , MgO, ZrO ₂ —Y ₂ O ₃ (YSZ), SrTiO ₃ , CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd _2. Examples thereof include metal oxides such as O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , and Nd ₂ O ₃ .
If the intermediate layer 14 is formed with good crystal orientation (for example, a crystal orientation degree of 15 ° or less) by ion beam assisted deposition (IBAD method), the crystal orientation of the cap layer 15 formed on the intermediate layer 14 Therefore, the oxide superconducting layer 16 formed on the cap layer 15 has a good crystal orientation and excellent superconducting characteristics. Can be demonstrated.

The thickness of the intermediate layer 14 may be adjusted as appropriate according to the purpose, but is usually in the range of 0.005 to 2 μm.
The intermediate layer 14 is formed by physical vapor deposition such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, ion beam assisted vapor deposition (hereinafter abbreviated as IBAD), chemical vapor deposition (CVD). Method: coating pyrolysis method (MOD method); lamination can be performed by a known method for forming an oxide thin film such as thermal spraying. In particular, the metal oxide layer formed by the IBAD method is preferable in that it has a high crystal orientation and a high effect of controlling the crystal orientation of the oxide superconducting layer 16 and the cap layer 15. The IBAD method is a method of orienting crystal axes by irradiating an ion beam at a predetermined angle with respect to an underlying vapor deposition surface during vapor deposition. Usually, an argon (Ar) ion beam is used as the ion beam. For example, the intermediate layer 14 made of Gd ₂ Zr ₂ O ₇ , MgO or ZrO ₂ —Y ₂ O ₃ (YSZ) has a small value of ΔΦ (FWHM: full width at half maximum), which is an index representing the degree of crystal orientation in the IBAD method. This is particularly preferable because it can be performed.

The cap layer 15 is preferably formed through a process of epitaxial growth on the surface of the intermediate layer 14 and selective growth of crystal grains in the in-plane direction. Such a cap layer 15 has a higher in-plane orientation than the intermediate layer 14 made of the metal oxide layer.
The material of the cap layer 15 is not particularly limited as long as it can exhibit the above function, but specific examples of preferable materials include CeO ₂ , LMO (LaMnO ₃ ), Y ₂ O ₃ , Al ₂ O ₃ , Gd. Examples include ₂ O ₃ , Zr ₂ O ₃ , Ho ₂ O ₃ , Nd ₂ O _{3 and the} like. When the material of the cap layer 15 is CeO ₂ , the cap layer 15 may include a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.

    The thickness of the cap layer 15 may be 50 nm or more, but is preferably 100 nm or more, and more preferably 300 nm or more in order to obtain sufficient orientation. However, if the thickness is too thick, the crystal orientation deteriorates, so the thickness is preferably 300 to 1000 nm.

The oxide superconducting layer 16 may be a known material, specifically, a material made of REBa ₂ Cu ₃ Oy (RE represents a rare earth element such as Y, La, Nd, Sm, Er, Gd), Y123 ( YBa ₂ Cu ₃ O _7-X ) or Gd123 (GdBa ₂ Cu ₃ O _7-X ) and other oxide superconductors, such as Bi ₂ Sr ₂ Can-1CunO _{4 + 2n + δ} The thing which consists of another high oxide superconductor can be illustrated.
The oxide superconducting layer 16 has a thickness of about 0.5 to 5 μm and preferably a uniform thickness.
The oxide superconducting layer 16 is laminated by a physical vapor deposition method such as sputtering, vacuum vapor deposition, laser vapor deposition, electron beam vapor deposition, chemical vapor deposition (CVD), or coating pyrolysis (MOD). In particular, from the viewpoint of productivity, TFA-MOD method (organic metal coating pyrolysis method using trifluoroacetate), PLD method or CVD method can be used.

  As described above, when the oxide superconducting layer 16 is formed on the cap layer 15 having good orientation, the oxide superconducting layer 16 laminated on the cap layer 15 also matches the orientation of the cap layer 15. Crystallize as follows. Therefore, the oxide superconducting layer 16 formed on the cap layer 15 is hardly disturbed in the crystal orientation, and the thickness of the metal substrate 11 is one for each crystal grain constituting the oxide superconducting layer 16. The c-axis is oriented in the vertical direction, and the a-axis or the b-axis is oriented in the length direction of the metal substrate 11. Therefore, since the obtained oxide superconducting layer 16 is hardly deteriorated in superconducting characteristics at the crystal grain boundary, it becomes easy to flow electricity in the length direction of the metal substrate 11, and a sufficiently high critical current density can be obtained.

The protective layer 17 laminated on the oxide superconducting layer 16 is formed as a layer made of a metal material that has good conductivity such as Ag and has low contact resistance with the oxide superconducting layer 16 and is compatible. . The protective layer 17 is made of a highly conductive metal material and functions as a bypass through which the current of the oxide superconducting layer 16 commutates when the oxide superconducting layer 16 attempts to transition from the superconducting state to the normal conducting state.
Of each configuration of the superconducting laminate 10 described so far, the diffusion prevention layer 12, the bed layer 13, and the cap layer 15 are not essential elements, and are appropriately used depending on the design conditions of the superconducting laminate 10.

Next, the manufacturing method of the oxide superconducting wire 1 of this embodiment is demonstrated. FIG. 4 is a flowchart showing a method for manufacturing the oxide superconducting wire 1 of the present embodiment.
In the manufacturing method of the present embodiment, the tape-shaped stabilization layer 21 is bent to cover the peripheral surface of the oxide superconducting laminate 10 in a U-shaped cross section, and the tape-shaped stabilization layer 21 is covered. Are provided with an insertion step S2 for accommodating the stabilizing material thin wire 22 inside the extending end portions 20a, 20a, and a joining step S3 for joining the extending end portions 20a, 20a and the stabilizing material thin wire 22.

In the manufacturing method of the present embodiment, the oxide superconducting laminate 10 is formed on the tape-shaped stabilization layer 21 having the solder layer 23 as shown in FIG. Is arranged so that the protective layer 17 side contacts. The solder layer 23 may contain tin (Sn).
At this time, the oxide superconducting laminate 10 is arranged so as to be shifted from the widthwise end of the tape-shaped stabilization layer 21 by a width corresponding to an extended end 21a described later, and the oxide superconducting laminate 10 and the tape-shaped stabilizing layer 21 are arranged. The wire layer position is temporarily fixed by heating the conversion layer 21 higher than the melting point of the solder layer 23.
The longer part of the tape-like stabilization layer 21 on the right side in the figure is bent and processed with respect to the temporarily fixed oxide superconducting laminate 10, and as shown in FIG. The layer 21 is formed in a U shape so as to come into contact with the peripheral surface of the oxide superconducting laminate 10. Thereby, the extended end portions 21a and 21a protruding in the width direction from the one surface 10a of the oxide superconducting laminate 10 are formed.

  Next, in the insertion step S2 shown in FIG. 4, as shown in FIG. 3 (c), the oxide superconducting laminate 10 is in contact with the one surface 10a between the opposing extended end portions 21a and 21a. The stabilizing material thin wire 22 is inserted over the entire length of the superconducting laminate 10, and the stabilizing material thin wire 22 is slightly thicker than the dimension in the stacking direction of the oxide superconducting laminate 10. For example, the stabilizer thin wire 22 may be about 10% thicker than the thickness of the oxide superconducting laminate 10. Further, as the stabilizing material thin wire 22, one having a solder layer 23 on the surface can be used. Thereby, as shown in FIG.3 (c), the extension end parts 21a and 21a deform | transform slightly in the direction (the up-down direction in the figure) which mutually spaces apart. Stabilizer thin wire 22 without solder layer 23 (without Sn plating) may be used.

Next, in the joining step S3 shown in FIG. 4, as shown in FIG. 3 (d), the stabilizer thin wire 22 slightly thicker than the oxide superconducting laminate 10 is formed in the extended end portions 21a and 21a. In a state of being disposed between them, the stabilizer thin wire 22 and the extended end portions 21a and 21a are joined to each other by applying pressure while heating to a temperature equal to or higher than the melting point of the solder layer 23 with a heating roller (not shown).
At this time, the solder layer 23 on the surface of the stabilizing material thin wire 22 and the extended end portions 21a and 21a is melted by heating with a heating roller, and at the same time, stable by pressing in the thickness direction of the oxide superconducting laminate 10. The chemical thin wire 22 is deformed to join the extended end portions 21 a and 21 a, and the extended end portions 21 a and 21 a are in close contact with the oxide superconducting laminate 10. At this time, the melted solder layer 23 fills the deformed stabilizer thin wire 22, the extended end portions 21 a and 21 a, and the gap portion of the oxide superconducting laminate 10. When the heating / pressurization by the heating roller is released, the cooled solder layer 23 is cooled and solidified, and the deformed stabilizing material thin wire 22, the extended end portions 21a and 21a, the oxide superconducting laminate 10 and the solder layer 23 are integrated. It becomes.
Thereby, the oxide superconducting wire 1 in which the oxide superconducting laminate 10 is sealed with one tape-shaped stabilizing layer 21, the stabilizing material thin wire 22, and the solder layer 23 is manufactured.

According to the present embodiment, the oxide superconducting laminate 10 is formed as a single tape-shaped stabilizing layer 21 by the solder layer 23 while crushed the stabilizer thin wire 22 that is slightly thicker than the dimension in the stacking direction of the oxide superconducting laminate 10. Since the stabilizing material thin wire 22 is connected, the stabilizing material thin wire 22 is deformed and compressed without applying a high pressure to the oxide superconducting laminate 10, and the oxide superconducting laminate 10 is hermetically sealed. It is possible to provide a structure that does not deteriorate.
At the same time, since the periphery of the oxide superconducting laminate 10 is hermetically sealed with the tape-shaped stabilizing layer 21 and the stabilizing material thin wire 22, the tape-shaped stabilizing layer can be obtained simply by processing the tape-shaped stabilizing layer 21 into a U-shaped cross section. The extending end portion 21a of 21 is joined without further bending to reduce the work man-hours, and the oxide superconducting laminate 10 is sealed while reducing the influence on the oxide superconducting laminate 10 during the sealing process. Thus, it is possible to prevent the deterioration of the superconducting characteristics.

As a result, the tape-shaped stabilization layer 21 can be simply folded in a U-shape, so that a simple structure can be obtained. Further, since one side of the oxide superconducting laminate 10 has a structure in which the tape-like stabilization layer 21 is simply bent, only the tape-like stabilization layer 21 located on the other side needs to be processed. Since the extended end portions 21 a and 21 a located on the other side of the oxide superconducting laminate 10 are spaced apart in parallel by the thickness dimension of the oxide superconducting laminate 10, processing is necessary for sealing. It is very difficult to bend the metal which is such a short tape-shaped stabilization layer 21, but a stabilizer thin wire 22 which is slightly thicker than the stacking direction dimension of the oxide superconducting laminate 10 is inserted and joined. Thus, the gap between the extended end portions 21a and 21a is closed. By providing a solder layer 23 on the surface of the tape-shaped stabilizing layer 21 and / or the stabilizing material thin wire 22 and heating / pressing it, the tape-shaped stabilizing layer 21 and the stabilizing material thin wire 22 are formed by soldering. Can be joined to form a sealed structure. Also, the solder layer 23 can be provided on the surface of the oxide superconducting laminate 10.
Further, as described above, it is not necessary to pressurize the oxide superconducting laminate 10 with a simple structure, and the oxide superconducting wire 1 capable of preventing deterioration of superconducting characteristics can be manufactured.

Hereinafter, 2nd Embodiment of the oxide superconducting wire which concerns on this invention is described based on drawing.
FIG. 5 is a cross-sectional view showing the oxide superconducting wire according to this embodiment. In the figure, reference numeral 1 denotes an oxide superconducting wire, and reference numeral 10 denotes a superconducting laminate constituting a part of the oxide superconducting wire 1. FIG. 6 is a cross-sectional view showing the steps of the method for manufacturing an oxide superconducting wire according to this embodiment.

  In the present embodiment, the only difference from the above-described first embodiment is the portion related to the stabilizing material thin wire 24 and the joining step S3. Is abbreviated.

In the insertion step S2 in the present embodiment, the stabilizing material thin wire 22 inserted in the first embodiment is set to be thicker than the dimension in the stacking direction of the oxide superconducting laminate 10, whereas FIG. As shown in c), the stabilizing material thin wire 24 of the present embodiment is set to be the same as or slightly thinner than the stacking direction dimension of the oxide superconducting laminate 10.
Specifically, the stabilizing material thin wire 24 of the present embodiment can be set to about 1.0 to 0.8 with respect to the stacking direction dimension of the oxide superconducting laminate 10.

  In joining process S3 in this embodiment, it heats and presses with a heating roller to such an extent that solder melts, and tape-like stabilization layer 21 and oxide superconducting layered product 10 are fixed. At this time, as shown in FIG. 6 (d), the gap between the stabilizing material thin wire 22, the extended end portions 21 a and 21 a and the oxide superconducting laminate 10 is filled with the molten solder layer 23. When the heating / pressurization by the heating roller is released, the cooled solder layer 23 is cooled and solidified, and the stabilizing material thin wire 22, the extended end portions 21a and 21a, the oxide superconducting laminate 10 and the solder layer 23 are integrated. The

  Next, as shown in FIG. 6 (e), the extended end portions 21a and 21a containing the integrated stabilizer thin wire 22 are made into a nitrogen atmosphere and laser irradiation is performed to locally heat the tape to stabilize it. The layer 21 and the stabilizing material thin wire 22 are laser welded. From the dimension setting of the stabilizing material thin wire 22, there is a slight gap between the tape-like stabilizing layer 21 and the stabilizing material thin wire 22, but it is deformed so that the stabilizing material (copper) melted by laser heating fills the gap. And integrated. Further, the solder (Sn) around the stabilizer thin wire 22 is melted by laser heating, but is deformed and moved so as to fill the gaps between the tape-like stabilizer layer 21, the stabilizer thin wire 22, and the oxide superconducting laminate 10. The welding of the tape-shaped stabilization layer 21 and the stabilizing material thin wire 22 is not affected.

  In the present embodiment, the same effects as those of the first embodiment described above can be obtained, and furthermore, the tape-shaped stabilization layer 21 and the stabilizing material thin wire 22 can be more reliably sealed by laser welding. Therefore, the oxide superconducting laminate 10 can be further prevented from being affected by moisture.

  In the first and second embodiments described above, the stabilizer thin wire 22 has been described as having a round cross-section, but in addition to this, as shown in FIG. 7, the oxide superconducting laminate 10 has a dimension in the stacking direction. The wire has a rectangular cross section having a corresponding one side dimension, and similarly has a thickness dimension corresponding to the stacking direction dimension of the oxide superconducting laminate 10 as shown in FIG. It is possible to use a tape-like thin wire having a width dimension of the body 10 larger than this. In the case of the wire having a rectangular cross section shown in FIG. 7, the sealing can be made more reliable by increasing the area where the wire 22 and the tape-shaped stabilization layer 21 are connected. In addition, when the tape-like thin wire 22 shown in FIG. 8 is used, the influence on the oxide superconducting laminate 10 due to pressurization is reduced by increasing the width dimension of the tape-like wire during processing by the heating roller. It becomes possible to do.

  Examples according to the present invention will be described below.

<Example 1>
An Al ₂ O ₃ diffusion prevention layer (thickness: 150 nm) by sputtering is formed on a tape-shaped base body having a width of 10 mm and a thickness of 100 μm made of Hastelloy C-276 (trade name of Haynes, USA), Y ₂ O ₃ bed layer (thickness 30 nm), MgO intermediate layer (thickness 10 nm) by IBAD method, CeO ₂ cap layer (thickness 300 nm) by PLD method (pulse laser deposition method), YBa by PLD method A tape-shaped oxide superconducting laminate in which an oxide superconducting layer (thickness: 1.0 μm) having a composition represented by ₂ Cu ₃ O _7-x and an Ag protective layer (thickness: 11 μm) formed by sputtering is formed. Prepared.

Next, the superconducting laminate is placed on a copper tape (width 20.5 mm, thickness 20 μm) with a solder layer that is Sn-plated on both sides. The position of the wire rod is temporarily fixed by heating (240 ° C.) the superconducting laminate and the copper tape by placing 0.2 mm away from the end of the Sn-plated copper tape. Then, the temporarily fixed superconducting laminate and the longer copper tape portion of the copper tape are aligned with the wire and bent into a U-shape. Next, a thin copper wire is put in a portion where the copper tape is in a U shape in the molded superconducting laminate. Use a copper wire that is slightly thicker than the superconducting laminate. Since the thickness of the superconducting laminate is 0.11 mm, the copper fine wire is thicker than 110 μm and has a thickness of 120 to 130 μm. The copper thin wire used was Sn plated (2 to 4 μm) (a copper thin wire not plated with Sn may be used). By heating (240 ° C.) and pressing with a heating roller a thin copper wire slightly thicker than the superconducting laminate, the copper tape Sn and the copper thin wire Sn are melted by heating, and at the same time the copper thin wire is heated. It is deformed and molded so that the U-shaped copper tape is in close contact with the superconducting laminate. The copper thin wire deformed by the melted Sn, the copper tape, and the gap of the superconducting laminate are filled. The wire that has passed through the heating roller is cooled to solidify Sn, and the superconducting laminate is integrated. As a result, the superconducting laminate was sealed with a piece of copper tape, copper fine wire, and melted Sn.
Ic was measured after holding the produced wire in an atmosphere of 121 ° C., 100%, 2 atm for 100 hours, and compared with the initial value, but Ic did not deteriorate. The result is shown in FIG.

<Example 2>
Similar to Example 1, a superconducting laminate (superconducting wire 10 mm, Hastelloy substrate 100 μm, thickness after Ag sputtering 11 μm) is prepared. Next, the superconducting laminate is placed on a copper tape (width 20.5 mm, thickness 20 μm) with a solder layer that is Sn-plated on both sides. The position of the wire rod is temporarily fixed by heating (240 ° C.) the superconducting laminate and the copper tape by placing 0.2 mm away from the end of the Sn-plated copper tape. Then, the temporarily fixed superconducting laminate and the longer copper tape portion of the copper tape are aligned with the wire and bent into a U-shape. Next, a thin copper wire is put in a portion where the copper tape is in a U shape in the molded superconducting laminate. Use a thin copper wire that is slightly thinner than the superconducting laminate. Since the thickness of the superconducting laminate is 0.11 mm, a thin copper wire having the same thickness as 110 μm or thinner (90 to 110 μm) is used. The copper thin wire used was Sn plated (2 to 4 μm) (a copper thin wire not plated with Sn may be used). Copper tape and superconductivity are melted by heating by heating (240 ° C) and pressurizing a thin copper wire slightly thinner than the superconducting laminate by heating (240 ° C) and pressurizing. Fix the laminate. Since the copper tape is slightly thinner than the superconducting laminate, it is fixed with almost no deformation. The melted Sn fills the fixed portion of the copper fine wire and the copper tape or the gap portion of the superconducting laminate. The wire rod that has passed through the heating roller is cooled, Sn is solidified, and the superconducting laminate is integrated.

Using a fiber laser (wavelength: 1065 μm, laser output: 300 W, spot diameter: 20 μm), the end of the integrated wire containing the copper fine wire is locally heated with a welding speed of 10 m / min and the laser irradiation location as a nitrogen atmosphere. Weld the copper tape and the copper wire. The copper tape and the copper thin wire portion have a small gap, but the copper melted by laser heating is deformed and integrated so as to fill the gap. Further, Sn around the copper fine wire is melted by laser heating, but the copper tape, the copper fine wire, and the superconducting laminate are deformed and moved so as to fill a gap portion of the superconducting laminate.
Thereby, it was set as the structure where a superconducting laminated body is sealed at the location where the copper tape of one sheet, the copper tape, and the copper fine wire were welded.
FIG. 9 shows the results of measuring Ic after holding the prepared wire in an atmosphere of 121 ° C., 100%, 2 atm for 100 hours and comparing it with the initial value, but no deterioration of Ic occurred.

<Comparative Example 1>
A copper tape (width 10 mm, thickness 20 μm) was bonded to the superconducting laminate produced in Example 1 with Sn.
Ic was measured after holding the prepared wire in an atmosphere of 121 ° C., 100%, 2 atm for 100 hours, and compared with the initial value, but Ic was deteriorated.

<Comparative Example 2>
The wire is processed in the same manner as in Example 1, and heated (240 ° C.) and pressurized with a heating roller without forming a copper fine wire, and then molded.
The Sn of the copper tape and the Sn of the copper thin wire are melted by the heating roller, and are fixed so that the copper tape and the superconducting laminate are in close contact with each other by pressurizing the superconducting laminate. Since the copper tape is U-shaped, one side is sealed, but one side is not sealed.
Ic was measured after holding the produced wire in an atmosphere of 121 ° C., 100%, 2 atm for 100 h, and Ic was deteriorated compared to the initial value. The result is shown in FIG.

  From these results, it can be seen that according to the present invention, the oxide superconducting laminate 10 is sealed without being deteriorated.

DESCRIPTION OF SYMBOLS 1 ... Oxide superconducting wire, 10 ... Superconducting laminated body, 10a ... One side surface, 11 ... Metal base material, 14 ... Intermediate | middle layer, 16 ... Oxide superconducting layer, 17 ... Protective layer, 20 ... Stabilization layer, 21 ... Tape Stabilizing layer, 21a ... extended end, 22, 24 ... stabilizing material thin wire, 23 ... solder layer

Claims (2)

An oxide superconducting laminate formed by laminating a tape-like base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order,
A tape-shaped stabilization layer having a U-shaped cross section covering the peripheral surface leaving one side surface laminated from the protective layer to the substrate of the oxide superconducting laminate;
The stacking direction of the oxide superconducting laminate is located on one side of the oxide superconducting laminate within the extending end of each of the tape-shaped stabilization layers protruding outward in the width direction of the oxide superconducting laminate A stabilizing material thin wire joined to the extending ends of the tape-shaped stabilization layer having a diameter corresponding to the height and protruding outward in the width direction of the oxide superconducting laminate. Ri name is sealed Te,
A method for producing an oxide superconducting wire in which the extending end of the tape-shaped stabilizing layer and the stabilizing material thin wire are joined by solder,
The step of covering the peripheral surface in a U-shaped cross section leaving one side of the oxide superconducting laminate by the tape-shaped stabilization layer;
Inserting the stabilizer thin wire into the extended end of each tape-shaped stabilization layer protruding outward in the width direction of the oxide superconducting laminate;
A step of joining the extending end portion of the tape-shaped stabilizing layer and the stabilizing material thin wire by heating and pressing,
A method for producing an oxide superconducting wire, characterized in that the diameter of the stabilizing thin wire to be inserted is set larger than the height in the stacking direction of the oxide superconducting laminate . An oxide superconducting laminate formed by laminating a tape-like base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order,
A tape-shaped stabilization layer having a U-shaped cross section covering the peripheral surface leaving one side surface laminated from the protective layer to the substrate of the oxide superconducting laminate;
The stacking direction of the oxide superconducting laminate is located on one side of the oxide superconducting laminate within the extending end of each of the tape-shaped stabilization layers protruding outward in the width direction of the oxide superconducting laminate A stabilizing material thin wire joined to the extending ends of the tape-shaped stabilization layer having a diameter corresponding to the height and protruding outward in the width direction of the oxide superconducting laminate. Ri name is sealed Te,
A method for producing an oxide superconducting wire in which the extending end of the tape-shaped stabilization layer and the stabilizing material thin wire are joined by a laser weld,
The step of covering the peripheral surface in a U-shaped cross section leaving one side of the oxide superconducting laminate by the tape-shaped stabilization layer;
Inserting the stabilizer thin wire into the extended end of each tape-shaped stabilization layer protruding outward in the width direction of the oxide superconducting laminate;
A step of joining the extended end portion of the tape-shaped stabilization layer and the stabilizing material thin wire by laser welding,
A method for producing an oxide superconducting wire, characterized in that the diameter of the stabilizing thin wire to be inserted is set smaller than the height in the stacking direction of the oxide superconducting laminate .

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