JP2013084382A - Oxide superconductive wire, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oxide superconductive wire formed into a sealed structure by covering an oxide superconductive layer with a base material and to provide a manufacturing method of the same.SOLUTION: An oxide superconductive laminate formed by laminating the base material, an intermediate layer, an oxide superconductive layer, and a conductive protection layer in this order is folded in two with the protection layer placed inside through a grooved portion reaching the base material from the protection layer. The folded parts of two oxide superconductive laminates are positioned at the end part sides of a beltlike conductor in the width direction thereof and the whole circumference of the conductor is surrounded by the two oxide superconductive laminates through a solder layer.

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 or the like is formed.
However, since Ag is an expensive metal and it is desirable that the amount used be small, the protective layer of Ag is formed thin, but there is a possibility that satisfactory moisture resistance cannot be obtained with a thin protective layer of Ag. Various structures are provided.
For example, an oxide superconducting conductor having a structure in which a stabilizing metal layer is formed by Cu plating and the entire circumference including the Ag protective layer and the oxide superconducting layer is covered with a Cu plating layer having a predetermined thickness up to the back side of the substrate. It has been known. (See Patent Document 1)
In addition, the oxide superconducting layer and the base material are covered with a copper foil for the purpose of forming a sealed structure, not a structure provided with an Ag protective layer, and the end of the copper foil covering the oxide superconducting laminate and the base material. An oxide superconductor having a structure in which edges are sealed with solder is provided. (See Patent Document 2)

JP 7-335051 A Japanese Patent No. 3949960

As described above, the oxide superconducting conductor having a structure in which the surface of the oxide superconducting layer is covered with a thin Ag protective layer has a structure that cannot cope with the intrusion of moisture from the side of the oxide superconducting layer. In addition, when a thin Ag protective layer is formed, if there is a pinhole in the protective layer, the Cu plating formed on the protective layer becomes uneven and the structure is easy for moisture to enter, and the superconducting characteristics deteriorate in a humid environment. There is a risk.
In addition, the oxide superconducting conductor with a structure in which the oxide superconducting layer and the base material are covered with copper foil has pinholes in the solder joint where the copper foil covering the base material is overlapped and joined with solder. Then, since moisture permeates into the oxide superconducting layer through this pinhole, the superconducting characteristics may deteriorate in a humid environment.

  The present invention has been made in view of the conventional situation as described above, and has a structure in which a base material provided with an oxide superconducting layer is bent and the oxide superconducting layer is wrapped by the base material, and thereby the oxide superconducting effect due to the influence of moisture. An object of the present invention is to provide an oxide superconducting conductor in which deterioration of the layer is eliminated and a method for producing the same.

  In order to solve the above-mentioned problems, the oxide superconducting wire of the present invention has an oxide superconducting laminate formed by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order. The two oxide superconducting laminates are folded in two with the protective layer inside through the grooved portion reaching the material, and the two bent portions are positioned on the widthwise end side of the strip-shaped conductor. The entire circumference of the conductor is surrounded by an oxide superconducting laminate via a solder layer.

The oxide superconducting wire having a structure in which the periphery of the oxide superconducting layer is surrounded by a base material and sealed since the two oxide superconducting laminates having a bent structure are surrounded by the solder layer around the entire circumference of the strip-shaped conductor Can provide. That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.
Since the base material is bent at an accurate position with the grooved portion as a base point through the grooved portion, when the conductor is surrounded by a bi-fold oxide superconducting laminate, the bent portion is accurately positioned at both ends of the conductor. In addition, the entire circumference of the conductor can be reliably covered with the oxide superconducting laminate having a bi-fold structure, and the oxide superconducting layer can be reliably sealed.
Since the oxide superconducting layer is divided through the grooved part and folded in half with the grooved part as the boundary, the strain and stress load associated with the bending is applied to the oxide superconducting layer in the part other than the grooved part. It is possible to suppress the deterioration of superconducting characteristics due to strain or stress load on the oxide superconducting layer.

  In order to solve the above-mentioned problems, the oxide superconducting wire of the present invention has an oxide superconducting laminate formed by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order. It is bent with the protective layer inside through two parallel grooved portions reaching the material, and a band-like conductor is encapsulated inside the bent portion via a solder layer, so that the conductor of the conductor is formed by the oxide superconducting laminate. The entire circumference is surrounded.

Since the oxide superconducting laminate with a bent structure is surrounded by a solder layer around the entire circumference of the conductor, the oxide superconducting wire with a structure in which the periphery of the oxide superconducting layer is enclosed by a solder layer and a base material is sealed. Can be provided. That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.
Since the base material is bent at an accurate position with the grooved portion as a base point through the grooved portion, the oxide superconducting laminate is placed on the peripheral surface side of the conductor when the conductor is surrounded by the bent oxide superconducting laminate. The oxide superconducting laminate having a folded structure can be accurately positioned along the conductor, so that the entire circumference of the conductor can be reliably covered, and a closed structure of the oxide superconducting layer with less risk of moisture intrusion can be realized.
Since the oxide superconducting layer is divided through the grooved part and bent at the grooved part, it is possible to suppress the strain and stress load associated with bending on the oxide superconducting layer other than the grooved part. In addition, it is possible to suppress deterioration of superconducting characteristics due to strain or stress load on the oxide superconducting layer.

  In order to solve the above-mentioned problems, the oxide superconducting wire of the present invention has an oxide superconducting laminate formed by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order. The conductor is bent with the protective layer inside through a plurality of parallel grooved portions reaching the material, and a conductor having a polygonal cross section is aligned with the outer peripheral corner of the conductor and the bent portion inside the bent portion. It is characterized in that it is enclosed via a layer, and the entire circumference of the conductor is surrounded by the solder layer and the oxide superconducting laminate.

Since the oxide superconducting laminate with a bent structure is surrounded by a solder layer around the entire circumference of the conductor, the oxide superconducting wire with a structure in which the periphery of the oxide superconducting layer is enclosed by a solder layer and a base material is sealed. Can be provided. That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.
Since the grooved portion is aligned with the outer corner of the conductor provided inside the folded oxide superconducting laminate, the folded oxide superconducting laminate can be accurately folded along the outer circumference of the conductor. In addition, since the oxide superconducting laminate having a bent structure can be accurately adhered along the outer periphery of the polygonal conductor, an oxide superconducting wire having a sealed structure that reliably covers the oxide superconducting layer can be provided.

In order to solve the above-mentioned problems, the oxide superconducting wire according to the present invention is characterized in that the butted portions of the edges of the oxide superconducting laminate provided so as to surround the entire circumference of the conductor are welded. And
The edges of the oxide superconducting laminate covering the entire circumference of the conductor are welded together, so that the oxide superconducting layer is sealed with the solder layer, and the oxide superconducting laminate is welded between the edges. Covering the oxide superconducting layer can further improve the hermeticity and provide a structure in which moisture hardly enters the oxide superconducting layer.

  In order to solve the above problems, the oxide superconducting wire manufacturing method of the present invention includes two oxide superconducting laminates in which a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer are laminated in this order. Prepare and form a straight grooved portion extending from the protective layer to the base material in these oxide superconducting laminates, with the two oxide superconducting laminates individually facing the protective layer through the grooved portion. The solder layer and the strip-shaped conductor are sandwiched between these oxide superconducting laminates as a double fold, and the entire circumference of the conductor is covered with the solder layer and the oxide superconducting laminate, and the solder layer is solidified after melting. A conductor and the oxide superconducting laminate are joined.

  The oxide superconducting wire with a structure in which the entire circumference of the conductor is covered so that two oxide superconducting laminates with a bent structure surround the solder layer, so that the periphery of the oxide superconducting layer is surrounded by the solder layer and the base material. Can be provided. That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.

  In order to solve the above problems, an oxide superconducting wire manufacturing method of the present invention provides an oxide superconducting laminate in which a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer are laminated in this order. In this oxide superconducting laminate, two straight grooved portions extending in parallel from the protective layer to the substrate are formed in parallel, and the oxide superconducting laminate is placed with the protective layer inside through these two grooved portions. The solder layer and the strip-shaped conductor are sandwiched between these bent portions, the entire circumference of the conductor is covered with the solder layer and the oxide superconducting laminate, and the solder layer is melted and solidified to be solidified with the conductor. The oxide superconducting laminate is bonded.

  Since the oxide superconducting laminate having a folded structure is surrounded by the solder layer around the entire circumference of the conductor, an oxide superconducting wire having a structure in which the periphery of the oxide superconducting layer is surrounded by the solder layer and the base material can be provided. . That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.

In order to solve the above problems, an oxide superconducting wire manufacturing method of the present invention provides an oxide superconducting laminate in which a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer are laminated in this order. Three or more linear grooved portions extending from the protective layer to the base material are formed in parallel in the oxide superconducting laminate, and the oxide superconducting laminate is attached to the protective layer via the three or more grooved portions. Folded inward, sandwiched between the striped conductor and the solder layer inside the oxide superconducting laminate, covered the entire circumference of the conductor with the solder layer and the oxide superconducting laminate, and solidified after melting the solder layer The conductor and the oxide superconducting laminate are joined together.
Since the oxide superconducting laminate having a folded structure is surrounded by the solder layer around the entire circumference of the conductor, an oxide superconducting wire having a structure in which the periphery of the oxide superconducting layer is surrounded by the solder layer and the base material can be provided. . That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.

In order to solve the above problems, the method of manufacturing an oxide superconducting wire according to the present invention includes welding the butted portions of the edges of the oxide superconducting laminate provided to surround the entire circumference of the conductor. Features.
By welding the edges of the oxide superconducting laminate covering the entire circumference of the conductor, the oxide superconducting layer is covered with a solder layer and sealed, and the welded oxide superconducting laminate is sealed with an oxide. Covering the superconducting layer can improve the hermeticity and provide a structure in which moisture hardly enters the oxide superconducting layer from the outside.

  According to the present invention, the entire circumference of the oxide superconducting layer is covered so that the folded oxide superconducting laminate is surrounded by the solder layer, so that the oxide superconducting layer is sealed with the oxide superconducting laminate. An oxide superconducting wire can be provided. That is, it is possible to provide an oxide superconducting wire having a hermetically sealed structure that can prevent moisture from entering the oxide superconducting layer from the outside of the substrate.

The perspective view which shows 1st Embodiment of the oxide superconducting wire which concerns on this invention. The block diagram which shows an example of the oxide superconducting laminated body applied to the oxide superconducting wire shown in FIG. FIG. 3A shows a process of manufacturing the oxide superconducting wire shown in FIG. 1, and FIG. 3A is a perspective view showing a state in which a groove processed portion is formed in two oxide superconducting laminates, FIG. FIG. 3C is a perspective view showing a state in which a solder layer is formed on two grooved oxide superconducting laminates, FIG. 3C is a perspective view showing a state in which a strip conductor is installed on the solder layer, and FIG. ) Is a perspective view showing a state in which two oxide superconducting laminates are bent through a grooved portion, and FIG. 3E is a perspective view showing an example of the obtained oxide superconducting wire. The block diagram which shows an example of the apparatus which manufactures the oxide superconducting wire shown in FIG. The perspective view which shows the oxide superconducting wire of 2nd Embodiment which concerns on this invention. FIG. 6A is a perspective view showing a state in which a grooved portion is formed in two oxide superconducting laminates, showing a process of manufacturing the oxide superconducting wire according to the second embodiment of the present invention. FIG. 6B is a perspective view showing a state in which a solder layer is formed on two grooved oxide superconducting laminates, and FIG. 6C shows a state in which a strip-shaped conductor is installed on the solder layer. A perspective view, FIG.6 (d) is a perspective view which shows the state which is bending the two oxide superconducting laminated bodies through a groove process part, FIG.6 (e) is an example of the obtained oxide superconducting wire. FIG. The perspective view which shows 3rd Embodiment of the oxide superconducting wire which concerns on this invention. The perspective view which shows 4th Embodiment of the oxide superconducting wire which concerns on this invention. The perspective view which shows 5th Embodiment of the oxide superconducting wire which concerns on this invention. The perspective view which shows the structure in the case of interconnecting the oxide superconducting wire of 1st Embodiment which concerns on this invention.

Hereinafter, an oxide superconducting wire according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view in which a part of the oxide superconducting wire according to the first embodiment of the present invention is shown in cross section, and the oxide superconducting wire A according to this embodiment is folded in two via a grooved portion 1. The processed oxide superconducting laminates 2 and 2 have an oxide superconducting layer 3 inside.
FIG. 2 is a partial cross-sectional perspective view showing the oxide superconducting laminate body 5 that is the basis of the double-folded oxide superconducting laminate 2 incorporated in the oxide superconducting wire A shown in FIG. In the oxide superconducting laminate body 5 shown in FIG. 2, an intermediate layer 6, an oxide superconducting layer 3, and a protective layer 7 are sequentially laminated on a tape-like substrate 4. Using the oxide superconducting laminate body 5 having this structure, the oxide superconducting laminate 2 shown in FIG. The oxide superconducting wire A is configured by enclosing a strip-shaped conductor (stabilizing conductor) 8 between the superconducting laminates 2 and 2 in a state surrounded by a solder layer 9.

  The oxide superconducting laminates 2 and 2 that are folded in a U-shaped cross section are integrated by abutting each other in the width direction edge 4a so that the entire circumference of the conductor 8 is surrounded by the solder layer 9. Has been placed. The butted portions of the end edges 4a of the oxide superconducting laminates 2 and 2 are preferably welded and integrated, and the oxide superconducting layer 3 provided inside the oxide superconducting laminates 2 and 2 is The entire circumference (outer circumference) is surrounded and sealed by the intermediate layer 6 and the substrate 4.

  The base material 4 applied to the oxide superconducting laminate body 5 shown in FIG. 2 is preferably in the form of a tape, a sheet or a thin plate in order to make a long wire, and is made of a heat-resistant metal. preferable. Among various refractory metals, a nickel alloy is preferable. Especially, if it is a commercial item, Hastelloy (US Haynes Corporation brand name) is suitable. The thickness of the base material 4 is usually 10 to 500 μm. Moreover, as the base material 4, an oriented Ni—W alloy tape base material in which a texture is introduced into a nickel alloy can also be applied.

The intermediate layer 6 is provided for the purpose of adjusting the crystal structure between the substrate 4 and the oxide superconducting layer 3 and preventing element diffusion of the constituent elements of the substrate. As an example, the intermediate layer 6 includes an underlayer, an alignment layer, a cap layer, Consists of
The underlayer can have a multi-layer structure of a diffusion prevention layer and a bed layer, which will be described below, or a structure composed of one of these layers.
In the case of providing a diffusion prevention layer as an underlayer, it is composed of silicon nitride (Si ₃ N ₄ ), aluminum oxide (Al ₂ O ₃ , also referred to as “alumina”), GZO (Gd ₂ Zr ₂ O ₇ ), or the like. A single layer structure or a multilayer structure is desirable, and the thickness is, for example, 10 to 400 nm.
When a bed layer is provided as an underlayer, the bed layer has high heat resistance, reduces interfacial reactivity, and is used for obtaining the orientation of a film disposed thereon. Such a bed layer is, for example, a rare earth oxide such as yttria (Y ₂ O ₃ ), and more specifically, 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 and the} like can be exemplified, and a single layer structure or a multilayer structure made of these materials can be adopted. The thickness of the bed layer is, for example, 10 to 100 nm. Further, the crystallinity of the diffusion preventing layer and the bed layer is not particularly limited, and may be formed by a film forming method such as a normal sputtering method.

The alignment layer functions as a buffer layer for controlling the crystal orientation of the oxide superconducting layer 3 and is made of a metal oxide having good lattice matching with the oxide superconducting layer, and is formed by the IBAD method (ion beam assisted deposition method). It is preferable that the film has a good orientation. Specifically, preferred materials for 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 , metal oxides such as Zr ₂ O ₃ , Ho ₂ O ₃ and Nd ₂ O ₃ can be exemplified. The alignment layer may be a single layer or a multilayer structure.

The cap layer is preferably formed through a process of epitaxially growing on the surface of the alignment layer and then selectively growing crystal grains in the in-plane direction. Such a cap layer may have a higher in-plane orientation degree than the orientation layer.
The material of the cap layer is not particularly limited as long as it can exhibit the above functions, but specifically, preferred examples include CeO ₂ , Y ₂ O ₃ , Al ₂ O ₃ , Gd ₂ O ₃ , and Zr ₂ O. ₃ , Ho ₂ O ₃ , Nd ₂ O _{3 and the} like. When the material of the cap layer is CeO ₂ , the cap layer may contain a Ce—M—O-based oxide in which part of Ce is substituted with another metal atom or metal ion.
The cap layer can be formed by a PLD method (pulse laser deposition method), a sputtering method, or the like. The thickness of the CeO ₂ cap layer may be 50 nm or more, but is preferably 100 nm or more in order to obtain sufficient orientation. However, if it is too thick, the crystal orientation deteriorates, so the thickness can be in the range of 50 to 5000 nm.

The oxide superconducting layer 3 can be widely applied to an oxide superconductor having a generally known composition. ReBa ₂ Cu ₃ O _7-x (Re is Y, La, Nd, Sm, Er, Gd For example, Y123 (YBa ₂ Cu ₃ O _7-x ) or Gd123 (GdBa ₂ Cu ₃ O _7-x ) can be exemplified. Further, other oxide superconductors, for _{example, Bi 2 Sr 2 Ca n-} 1 Cu n for _{O 4 + 2n + δ} becomes may be used in compositions such as those made of other oxide superconductors having high critical temperatures representative Of course. The oxide superconducting layer 3 has a thickness of about 0.5 to 5 μm and preferably a uniform thickness.
The protective layer 7 formed so as to cover the upper surface of the oxide superconducting layer 3 is made of Ag, and is formed by a normal sputtering apparatus such as a DC sputtering apparatus or an RF sputtering apparatus. It is about 30 μm.

The band-like conductor 8 included in the oxide superconducting laminates 2 and 2 processed into two folds is made of a highly conductive metal material, and the oxide superconducting layer 3 is changed from the superconducting state to the normal conducting state. Together with the protective layer 7, it functions as a bypass for commutating current. The metal material constituting the conductor 8 is not particularly limited as long as it has good conductivity, but is not limited to copper alloy such as copper, brass (Cu—Zn alloy), Cu—Ni alloy, Al, Cu—Al. It is preferable to use a material made of a relatively inexpensive material such as an alloy. Among them, it is preferable that the material is made of copper because it has high conductivity and is inexpensive. When the oxide superconducting wire is used for a superconducting fault current limiter, the conductor 8 is made of a high resistance metal material, and is made of, for example, a Ni-based alloy such as Ni—Cr. The thickness of the conductor 8 is not particularly limited and can be adjusted as appropriate, but is preferably 50 to 300 μm.
The oxide superconducting wire A in this example is used for winding a superconducting coil in a state where the outer periphery of the oxide superconducting wire A is insulated and coated by means such as winding an insulating tape.

In order to manufacture the oxide superconducting wire A having the structure shown in FIG. 1, a tape-shaped oxide superconducting laminate body 5 having the laminated structure shown in FIG. 2 is produced.
As an example of a method for manufacturing the oxide superconducting laminate body 5, after forming a diffusion prevention layer and a bed layer on the substrate 4 by a sputtering method, an alignment layer is formed on the bed layer by an IBAD method, A cap layer is formed by the PLD method to form the intermediate layer 6, and the oxide superconducting layer 3 is further formed thereon by the PLD method. Next, an Ag protective layer is formed on the upper surface of the oxide superconducting layer 3 by sputtering. 7 can be formed to produce the oxide superconducting laminate body 5 having the structure shown in FIG. The thickness of the Ag protective layer 7 is in the range of about 1 to 30 μm. After forming the protective layer 7 of Ag, the oxide superconducting laminate body 5 is subjected to an annealing process of heating to about 500 ° C. in an oxygen atmosphere, and oxygen is supplied to the crystal of the oxide superconducting layer 3 and the crystal Arrange the structure.

Next, with the protective layer 7 of the oxide superconducting laminate body 5 facing upward, the groove is formed so as to reach the base material 4 from the protective layer 7 along the longitudinal direction from the intermediate portion in the width direction of the oxide superconducting laminate body 5. The straight groove processing portion 11 is formed by processing. The formation method of the groove processing part 11 is not particularly limited, and a conventionally known method can be applied, but it can be formed by a method such as laser irradiation or groove processing with a rotary blade. As shown in FIG. 3, when using a laser processing machine (laser irradiation apparatus) 13, there is no possibility that the oxide superconducting laminate body 5 is deformed by stress or pressure during processing. The width and depth of the grooved portion 11 can be easily adjusted by adjusting the laser output and the thickness of the rotary blade.
The width of the groove processing portion 11 is set to about 20 to 100 μm, and the depth of the groove processing portion 11 is formed to a depth of about 1/3 to 1/2 of the thickness of the base material 4.

  Next, as shown in FIG. 3 (b), two oxide superconducting laminate bodies 5 in which the grooved portions 11 are formed are horizontally arranged adjacent to each other, and two oxide superconducting laminate bodies 5 are arranged adjacent to each other. A solder layer 12 is formed along the entire upper surface of the protective layer 7 with a solder tape or the like. The thickness of the solder layer 12 is about 20 to 30 μm. The solder layer may be either a solder tape applied or a solder layer applied. Further, as the material of the solder layer 12, tin, a tin-silver alloy, a tin-bismuth alloy, or the like can be used as appropriate.

Next, with respect to the two oxide superconducting laminate bodies 5 arranged adjacent to each other, as shown in FIG. 3C, a conductor 8 made of a strip-shaped metal tape having a width equal to the width of one oxide superconducting laminate body 5 is used. Are placed evenly across the two oxide superconducting laminate bodies 5 and 5. When the conductor 8 is installed as shown in FIG. 3 (c), the grooved portions 11, 11 are aligned below the both ends of the conductor 8 in the width direction.
Next, the two oxide superconducting laminate bodies 5 are sequentially folded in half along the longitudinal direction of each oxide superconducting laminate body 5 as shown in FIG. . In addition, from the viewpoint of improving the workability at the time of bending, the grooved portion 11 is provided so as to reach a depth of about 1/3 to 1/2 of the thickness of the base material 4 as described above. Is preferred.

When the base materials 4 and 4 are bent over the entire length in the length direction of each oxide superconducting laminate body 5, the structure shown in FIG. 3 (e) can be obtained. When heated, the solder layer 12 can be melted, and then cooled to room temperature to solidify the molten solder so that the oxide superconducting laminate 2 brazed around the conductor 8 is brazed. Superconducting wire A is obtained. As the solder, tin solder, tin-silver alloy solder, or tin-bismuth alloy solder can be used.
Thereafter, the sealing structure can be further strengthened by welding and integrating the butted portions of the width direction end edges 4a of the substrates 4 and 4 as necessary.

In the manufacturing process, if the base material 4 is processed in half without providing the groove processing portion 11, stress concentrates on the bent portion of the oxide superconducting layer 3, and as a result, the oxide superconducting layer 3 has an indefinite shape. Therefore, there is a high possibility that the superconducting characteristics of the oxide superconducting wire A will be greatly deteriorated. On the other hand, when the oxide superconducting laminate body 5 is processed in two by providing the groove processing portion 11, there is no possibility of applying unnecessary stress to the oxide superconducting layer 3 around the bent portion, and the oxide superconducting layer. Therefore, it is possible to obtain an oxide superconducting wire A having excellent superconducting characteristics which does not cause deterioration of superconducting characteristics due to generation of cracks or stress load.
The oxide superconducting layer 3 is a crystalline ceramic thin film and is particularly vulnerable to bending loads and physical impacts. Therefore, it is particularly effective to prevent the deterioration of the superconducting characteristics by forming the grooved portion 11 and bending it at the boundary. It is.

Next, the case where the manufacturing method of the oxide superconducting wire A of the present embodiment is performed using the manufacturing apparatus 30 having the configuration shown in FIG. 4 will be described.
As shown in FIG. 4, the manufacturing apparatus 30 includes laser processing machines (laser irradiation apparatuses) 13 and 13 for grooving the oxide superconducting laminate body 5, and the solder tape 20 along the oxide superconducting laminate body 5. A solder alignment mechanism 50 for laminating and forming the solder layer 12, a conductor alignment mechanism 52 for aligning the tape-like conductor 21 serving as a stabilizing material on the solder tape 20, and the conductor 21 for two oxides. A laminating mechanism 53 for positioning and temporarily fixing the superconducting laminate body 5, a folding mechanism 40 for processing the oxide superconducting laminate body 5 into two folds through a groove processing portion, and a folded oxide superconducting laminate And a fixing mechanism 60 for fixing the main body 5.

  A tape-shaped oxide superconducting laminate body 5 is wound around the introduction side of the manufacturing apparatus 30, and two first reel devices 31 capable of feeding the oxide superconducting laminate body 5 and a solder tape 20 are provided. A second reel device 32 that is wound and capable of feeding the solder tape 20 and a third reel device 33 around which the tape-like conductor 21 is wound and capable of feeding the conductor 21 are provided. Further, a conveying roller 51 for guiding the two superconducting laminate bodies 5 sent out in parallel with the solder 50 and a winding device 34 for winding up the oxide superconducting wire A formed by the fixing mechanism 60 are provided. It has been.

As shown in FIG. 4, the fixing mechanism 60 includes a main heating mechanism (heating unit) 61 that heats the oxide superconducting laminate in which the solder layers are laminated and folded in half to a temperature equal to or higher than the melting point of the solder layers, A pair of pressure rolls 62 are provided for gradually cooling while pressing the folded oxide superconducting laminate so as to fix them.
The two oxide superconducting laminates that have been folded in two are heated to a predetermined temperature by passing through the heating mechanism 61. The pressure roll 62 has a heater (not shown) and a brush (not shown) attached on the outer peripheral surface of the pressure roll 62.

  In the manufacturing apparatus 30 configured as described above, the oxide superconducting laminate main bodies 5 and 5 are supplied from the first reel apparatuses 31 and 31 to the solder alignment mechanism 50 and the conductor alignment mechanism 52, and the solder tape 20 and the conductor 21 are sequentially supplied. Then, the conductor 21 is supplied to the conductor alignment mechanism 52, and the conductor 21 is positioned and temporarily fixed by the bonding mechanism 53, and then the oxide superconducting laminate body 5, 5 is bent via the groove processing portion 11 by the bending mechanism 40. The oxide superconducting wire A can be continuously manufactured by being heated and pressurized by the heating mechanism 61 and the pressure roller 62 and can be wound around the winding device 34.

FIG. 5 is a perspective view in which a part of the oxide superconducting wire according to the second embodiment of the present invention is shown in cross section. As shown in FIG. 5, the oxide superconducting wire B of the second embodiment has an oxide superconducting layer 3 on the inner side of an oxide superconducting laminate 16 in which both ends are folded through groove processing portions 1 arranged on both sides in the width direction. The structure is embedded.
The oxide superconducting wire B having the structure shown in FIG. 5 uses a laminate body having the same structure as the oxide superconducting laminate body 5 shown in FIG. 2, but the oxide superconducting laminate body of the first embodiment described above. A laminate body that is about twice as wide as 5 is used. The oxide superconducting laminate 16 is applied by folding both ends of the laminate body so as to have a C-shaped cross section.

To manufacture the oxide superconducting wire B of the second embodiment, a wide oxide superconducting laminate body 17 is used as shown in FIG. 6A, and the laser processing machine 13 is formed on the upper surface of the laminate body 17. , 13 are used to form two parallel grooved portions 11. The interval between the two parallel grooved portions 11 is the same width as the conductor 8 used later.
After the groove processing, as shown in FIG. 6B, the solder layer 12 is formed in the same manner as described with reference to FIG. 3B, and then the conductor 8 is formed as shown in FIG. 6C. 3 (c), and the oxide superconducting laminate main body 17 is shown in FIG. 6 (d) as in the case described with reference to FIG. 3 (d). The oxide superconducting wire B having the structure shown in FIG. 6 (e) can be obtained by bending in this manner and then melting and cooling the solder layer 12.
In addition, if the butt portion of the edge 16a of the oxide superconducting laminate 16 is welded, a structure with better sealing property can be obtained as a joint structure.

  The oxide superconducting wire B of the second embodiment can obtain the same effects as the oxide superconducting wire A of the first embodiment, but from one oxide superconducting laminate body 17 to the oxide superconducting wire B. Has the advantage that can be obtained.

FIG. 7 is a perspective view, partly in section, of an oxide superconducting wire according to a third embodiment of the present invention. As shown in FIG. 7, in the oxide superconducting wire C of the third embodiment, the oxide superconducting layer 3 is encapsulated inside the oxide superconducting laminates 22 and 22 processed in a folded manner via the groove processing portion 1A. Structure.
The oxide superconducting wire C having the structure shown in FIG. 7 covers the oxide superconducting laminate body 5 shown in FIG. 2 with a stabilizing layer 28 made of a metal such as Cu to be a stabilizing material on the protective layer 7. The oxide superconducting laminate 22 is applied by using the above-described oxide superconducting laminate body and folding the laminate body into two in a U-shaped cross section.
And the oxide superconducting wire C is comprised by enclosing the strip | belt-shaped conductor (stabilizing conductor) 8 which consists of metals between the two oxide superconducting laminated bodies 22 and 22 in the state enclosed by the solder layer 29. FIG. . Note that if the butt portion of the end edge 22a of the oxide superconducting laminate 22 is welded, a structure with better sealing properties can be obtained as a joint structure.

The oxide superconducting wire C of the third embodiment shown in FIG. 7 can be manufactured by a manufacturing method equivalent to the manufacturing method of the oxide superconducting wire A of the first embodiment described above. The oxide superconducting wire A according to the first embodiment is manufactured in accordance with the process shown in FIG. 3 using the oxide superconducting laminate body 5 having the structure shown in FIG. 2, but the oxide superconducting laminate body is the stabilizing layer 28 described above. By manufacturing according to the process shown in FIG. 3 as an attached oxide superconducting laminate body, the oxide superconducting wire C of the third embodiment can be obtained.
Although the oxide superconducting wire C of the third embodiment can obtain the same effects as the oxide superconducting wire A of the first embodiment, the oxide superconducting wire C of this embodiment is stable with the conductor 8. It is possible to realize a structure including a stabilizing material having a two-layer structure composed of the stabilizing layer 28.

  FIG. 8 is a perspective view with a cross section of a part of the oxide superconducting wire according to the fourth embodiment of the present invention. As shown in FIG. 8, the oxide superconducting wire D according to the fourth embodiment has oxide superconducting materials inside the oxide superconducting laminates 42 and 42 processed into a J-shaped cross section through the grooved portion 1B. The layer 3 is included. The folded oxide superconducting laminates 42 and 42 are integrated by the solder layer 9. Further, it is more preferable that the oxide superconducting laminates 42 and 2 are integrated by abutting and welding the both end edges 42a and 42a in the width direction, so that the entire circumference of the oxide superconducting layer 3 is oxidized. A structure surrounded and sealed by the superconducting laminates 42 and 42 is applied.

  When the oxide superconducting laminate main body 5 having the above-described laminated structure shown in FIG. 2 is folded in half, when it is equally folded in half so as to have a U-shaped cross section with respect to the width of the base material 4 In addition, as shown in FIG. 8, it may be bent with a non-uniform width so as to have a J-shaped cross section with respect to the width of the substrate 4. In the present embodiment, the main point is that the oxide superconducting laminates 42 and 42 need only be bent into a shape that can surround the entire periphery of the oxide superconducting layer 3.

FIG. 9 is a perspective view, partly in section, of an oxide superconducting wire according to the fifth embodiment of the present invention. As shown in FIG. 9, the oxide superconducting wire E of the fifth embodiment has an oxide superconducting layer 3 inside an oxide superconducting laminate 45 processed into a C-shaped cross section through four grooved portions 1C. It has a structure in which a thick conductor 38 having a rectangular cross section is disposed in the center. The oxide superconducting laminate 45 and the conductor 38 at the center thereof are integrated by a solder layer 39.
Further, it is more preferable that the oxide superconducting laminate 45 processed into a C-shape is integrated by butt-welding both end edges 45a and 45a in the width direction. With this structure, the oxide superconducting layer 3 is integrated. A sealed structure in which the entire periphery is more firmly surrounded by the base material 4 is provided.

The laminated structure of the oxide superconducting laminate 45 applied to the present embodiment is the same structure as the oxide superconducting laminate body 5 described above with reference to FIG. The difference is that four lines are formed at predetermined intervals in parallel.
This embodiment is an embodiment in which a strip-like conductor 38 thicker than the conductor 8 of the first embodiment shown in FIG. 1 is provided at the center of the oxide superconducting wire C. When the conductor 38 disposed in the center is thick and the groove processed portion formed in the oxide superconducting laminate main body cannot be handled by only two, the conductor 38 is positioned outside the outer peripheral corner of the conductor 38 having a rectangular cross section. A structure in which the groove processing portions 1C of the book are arranged can be adopted.
With this structure, the oxide superconducting laminate 45 can be disposed in close contact with the outer periphery of the thick conductor 38 in a state where the risk of applying a load such as strain to the oxide superconducting layer 3 of the oxide superconducting laminate 45 is reduced. it can.

  The conductor 38 disposed at the center as in this embodiment is not limited to a rectangular cross section, but may be a polygonal shape such as a triangular, pentagonal, hexagonal cross section, and any of these shapes. However, the oxide superconducting laminate 45 is formed with a necessary number of grooved portions and closely adhered along the periphery of the conductor 38, and then the solder layer is melted, and then cooled to the oxide 38 in the conductor 38. The laminated body 45 can be integrated as a sealed structure.

  As shown in FIG. 9, an oxide having a structure in which the oxide superconducting layer 3 is enclosed and sealed by providing a plurality of grooved portions 1 </ b> C corresponding to a polygonal conductor with one oxide superconducting laminate 45. Superconducting wire E can be provided.

FIG. 10 is a perspective view for explaining a structure suitable for joining two oxide superconducting wires A having the structure shown in FIG.
When two oxide superconducting wires A are joined, the bases 4 and 4 are removed by a predetermined length at the end of one oxide superconducting wire A, and the conductor 8 is connected to the ends of the bases 4 and 4 by a predetermined length. The base material 4 and 4 are opened by a predetermined length at the end of the other oxide superconducting wire A to expose the conductor 8. From this state, after superposing the conductor 8 of one oxide superconducting wire A and the conductor 8 of the other oxide superconducting wire A, the base materials 4 and 4 of both oxide superconducting wires A are bent again to conduct the conductor 8. , 8 can be sealed and soldered so that the oxide superconducting wires A and A can be electrically joined.
Although the oxide superconducting wires A and the oxide superconducting layers 3 and 3 of the A are not directly superconductingly joined, the electrical resistance corresponding to the presence of the conductors 8 and 8 at the joint is generated. By performing the bonding shown in FIG. 10, the oxide superconducting wires A and A can be electrically bonded.

EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to the Example described below.
"Example 1"
On a tape-shaped base body having a width of 10 mm, a thickness of 0.1 mm and a length of 100 m made of Hastelloy C-276 (trade name of Haynes, USA), an Al ₂ O ₃ diffusion prevention layer (thickness 80 nm), Bed layer (thickness 30 nm) of Y ₂ O ₃ , MgO intermediate layer (thickness 10 nm) by ion beam assisted vapor deposition, and CeO ₂ cap layer (thickness 300 nm) by PLD method (pulse laser vapor deposition) And an oxide superconducting layer having a composition represented by YBa ₂ Cu ₃ O _7-x by PLD method and a protective layer of Ag (thickness 10 μm) by sputtering and forming a tape-like oxide superconducting layer Prepared the body.

The oxide superconducting laminate is subjected to an oxygen annealing treatment at 500 ° C., then, as shown in FIG. 3 (a), a YAG laser processing machine is used to reach a width of 100 μm from the protective layer to the base material. A groove processed portion reaching half of the width was formed in the central portion of the width of the oxide superconducting laminate over the entire length. Two oxide superconducting laminates with grooves formed thereon were adjacent to each other in parallel and covered with a tin solder tape covering the entire upper surface thereof. A conductor for forming a stabilizing material made of Cu having a width of 10 mm and a thickness of 0.1 mm was disposed at the center of the solder tape.
The oxide superconducting laminates adjacent to the left and right are bent into U-shapes through the grooved portions, respectively, and the entire circumference of the conductor is surrounded by the oxide superconducting laminate, and then the solder tape melting temperature 270 The solder was melted by heating to 0 ° C., and then cooled to room temperature to obtain an oxide superconducting wire in which the oxide superconducting laminate was surrounded by a solder layer.

When this oxide superconducting wire was subjected to a pressure cooker test (left in an environment of a temperature of 120 ° C. and a humidity of 100%), the critical current value of the oxide superconducting wire did not decrease even after 100 hours had elapsed.
Two oxide superconducting wires were prepared, immersed in liquid nitrogen, and measured for superconducting properties at 77K. The critical current value (Ic) was 200A.
From this test result, the oxide superconducting laminate that surrounds the oxide superconducting laminate with the oxide superconducting laminate and that the entire circumference of the conductor is joined to the oxide superconducting laminate by soldering can exhibit excellent moisture resistance. It became clear.

Of the two oxide superconducting wires, end treatment of one superconducting wire is performed to remove the base material at the end, the inner conductor protrudes 50 mm, and the base material of the other superconducting wire material is opened to open Cu. The conductors of 50 mm were laminated and bonded together, the base material of the part where the conductors were overlapped was bent again, the solder was melted again, and two oxide superconducting wires were joined.
After joining, the superconducting property at 77K was measured by immersing in liquid nitrogen including the joined part, and the critical current value (Ic) was 180A.
This value can be regarded as an effective joining as an electrical joining portion between the oxide superconducting wires.

With respect to the total length of the oxide superconducting wire having the same structure as the sample subjected to the pressure cooker test, an abutted portion of the base edge was laser welded over the entire length to obtain an oxide superconducting wire sample having a sealed structure.
When this oxide superconducting wire sample was subjected to a pressure cooker test (temperature: 120 ° C., humidity: 100%), no deterioration of superconducting properties was observed even after 150 hours.
From this test result, the oxide superconducting wire of this example surrounds the oxide superconducting laminate with the oxide superconducting laminate, solders the oxide superconducting laminate to the conductor, and welds the butt edge portion. As a result, it has been clarified that since the soldered portion and the welded portion are double-bonded, the sealing structure is excellent and the moisture resistance is superior to the previous example.

  The technology of the present invention can be used for oxide superconducting wires used in various power devices such as superconducting power transmission lines, superconducting motors, and current limiters.

  A, B, C, D, E ... oxide superconducting wire, 1, 1A, 1B, 1C ... grooved portion, 2, 16, 22, 42 ... oxide superconducting laminate, 3 ... oxide superconducting layer, 4 ... Base material, 4a ... edge, 5 ... oxide superconducting laminate body, 6 ... intermediate layer, 7 ... protective layer, 8 ... conductor (stabilizing material), 9 ... solder layer, 11 ... grooved portion, 12 ... solder Layer: 13 ... Laser processing machine (laser irradiation device), 16a ... edge, 20 ... solder tape, 21 ... conductor, 22a ... edge, 30 ... production device, 31 ... first reel device, 32 ... second reel device 33 ... 3rd reel device, 34 ... winding device, 42a ... edge, 51 ... conveying roller, 52 ... conductor alignment mechanism, 53 ... bonding mechanism, 60 ... fixing mechanism, 62 ... pressure roll.

Claims (8)

  An oxide superconducting laminate formed by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order is arranged with the protective layer inside through a grooved portion reaching from the protective layer to the base material. The two oxide superconducting laminates are folded in a folded manner, and the bent portions thereof are positioned on the end portions in the width direction of the strip-shaped conductor, and the entire circumference of the conductor is interposed via the solder layer by these two oxide superconducting laminates. An oxide superconducting wire characterized by being surrounded.   An oxide superconducting laminate formed by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order is formed through the two parallel groove processing portions extending from the protective layer to the base material. The oxide superconducting wire is characterized in that the conductor is surrounded by the oxide superconducting laminate by enclosing a strip-shaped conductor inside the bent portion via a solder layer. .   The oxide superconducting laminate formed by laminating the base material, the intermediate layer, the oxide superconducting layer, and the conductive protective layer in this order is provided with the protective layer via a plurality of parallel groove processing portions extending from the protective layer to the base material. The strip-shaped conductor having a polygonal cross section is encapsulated via a solder layer with the outer peripheral corner of the conductor aligned with the bent portion inside the bent portion, and the oxide superconducting laminate is used to An oxide superconducting wire characterized by being surrounded by a conductor.   The oxide superconducting wire according to any one of claims 1 to 3, wherein edges of the oxide superconducting laminate are butted together and the butted portion is welded.   Two oxide superconducting laminates are prepared by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order, and these oxide superconducting laminates form a straight line extending from the protective layer to the base material. A grooved portion is formed, and two oxide superconducting laminates are individually folded in two through the grooved portion with the protective layer inside, and a solder layer and a strip-shaped conductor are interposed between the oxide superconducting laminates. Covering the entire circumference of the sandwiched conductor with the solder layer and the oxide superconducting laminate, and melting and solidifying the solder layer to join the conductor and the oxide superconducting laminate A manufacturing method of a wire.   An oxide superconducting laminate is prepared by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order, and a linear groove extending from the protective layer to the base material on the oxide superconducting laminate. Two processed portions are formed in parallel, the oxide superconducting laminate is bent with the protective layer inside through the two groove processed portions, and a solder layer and a strip-shaped conductor are sandwiched between the bent portions, An oxide superconducting wire characterized by covering the entire circumference of a conductor with the solder layer and the oxide superconducting laminate, and solidifying the solder layer after melting and joining the conductor and the oxide superconducting laminate. Production method.   An oxide superconducting laminate is prepared by laminating a base material, an intermediate layer, an oxide superconducting layer, and a conductive protective layer in this order, and a linear groove extending from the protective layer to the base material on the oxide superconducting laminate. Three or more processed parts are formed in parallel, the oxide superconducting laminate is bent with the protective layer inside through the three or more grooved parts, and a strip-shaped conductor and solder are placed inside the oxide superconducting laminate. An oxide comprising sandwiching the layers, covering the entire circumference of the conductor with the solder layer and the oxide superconducting laminate, and solidifying the solder layer after melting, thereby joining the conductor and the oxide superconducting laminate Manufacturing method of superconducting wire.   8. A solder layer is used as the conductive bonding material, and the oxide superconducting laminate is electrically bonded to a metal conductor by melting and solidification of the solder layer accompanying heat treatment and cooling treatment. The manufacturing method of the oxide superconducting wire as described in any one of these.

Images