JP4934155B2 - Superconducting wire and method of manufacturing superconducting wire - Google Patents

Description

  The present invention relates to a superconducting wire and a method of manufacturing a superconducting wire, and more particularly to a superconducting wire and a method of manufacturing a superconducting wire that can improve the yield of the superconducting wire and reduce the manufacturing cost.

  Currently, a superconducting wire using a bismuth-based superconductor mainly composed of Bi2223 phase produced by a powder-in-tube method (hereinafter also referred to as “bismuth-based superconducting wire”), and a metal substrate. The development of two types of superconducting wires, particularly superconducting wires using RE123-based superconductors formed by a vapor phase method or a liquid-phase method (hereinafter sometimes referred to as “RE123-based superconducting wires”), is being promoted. ing.

  Among these, the RE123-based superconducting wire has an advantage that the critical current density at the liquid nitrogen temperature (77.3 K) is higher than that of the bismuth-based superconducting wire. Further, the RE123-based superconducting wire has an advantage that the critical current value is high under a low temperature and a constant magnetic field. Therefore, RE123-based superconducting wires are expected as next-generation high-temperature superconducting wires.

  Hereinafter, a conventional method for manufacturing a RE123-based superconducting wire will be described (for example, see Patent Document 1).

  First, as shown in a schematic cross-sectional view of FIG. 14, an intermediate layer 102 made of YSZ (yttria stabilized zirconia) or the like is formed on a base material 101 made of Hastelloy C-276 by RF sputtering (Patent Document). 1 paragraph [0021]).

Next, as shown in the schematic cross-sectional view of FIG. 15, an oxide superconducting layer made of RE123-based superconductor such as Y ₁ Ba ₂ Cu ₃ O _7-x based on the laser deposition method on the intermediate layer 102. 103 (see paragraph [0021] of Patent Document 1).

  Next, as shown in the schematic cross-sectional view of FIG. 16, a base stabilization thin film 104 made of silver is formed on the oxide superconducting layer 103 by sputtering (see paragraph [0023] of Patent Document 1). Thereafter, the element conductor 106, which is a laminate of the base material 101, the intermediate layer 102, the oxide superconducting layer 103, and the base stabilizing thin film 104, is subjected to heat treatment in an atmosphere containing oxygen gas (paragraph [0023] of Patent Document 1). reference).

  Thereafter, as shown in the schematic cross-sectional view of FIG. 17, a stabilization layer 105 made of copper is formed on the underlying stabilization thin film 104 of the element conductor 106 by electroplating (paragraph [0024] of Patent Document 1). reference). Here, the plating solution used for forming the stabilization layer 105 has a cyan composition.

  Finally, the tape-shaped RE123-based superconducting wire is manufactured by heat-treating the element conductor 106 after the formation of the stabilization layer 105 in a nitrogen gas atmosphere (see paragraph [0024] of Patent Document 1).

JP-A-7-73759

  In the above-described conventional RE123-based superconducting wire manufacturing method, the element conductor 106 before the formation of the stabilization layer 105 such as copper is arranged in the longitudinal direction of the element conductor 106 as shown in the schematic plan view of FIG. It is divided into element conductor main body part 106a and element conductor ear part 106b whose width is reduced by being slit along. Thereafter, the element conductor ear portion 106b is discarded, but the element conductor main body portion 106a is immersed in the plating solution, and the stabilization layer 105 is formed by electroplating.

  Here, the slit processing of the element conductor 106 is performed at the same time as pressing the block upper blade 107a downward from the upper surface of the element conductor 106 using a conventionally known gang slitter as shown in the schematic side view of FIG. This is performed by pressing the block lower blade 107b upward from the lower surface of the element conductor 106 to cut the element conductor 106.

  FIG. 20 is a schematic cross-sectional view of the element conductor main body 106a obtained by cutting the element conductor 106 using a gang slitter. Here, strain (tensile stress) is generated in the side portion of the base stabilizing thin film 104 of the element main body 106a by cutting using a gang slitter.

  However, when the element main body 106a in a state where such strain (tensile stress) is generated is immersed in a cyan plating solution, the oxide superconducting layer 103 is dissolved by the plating solution to stabilize the base. The strain (tensile stress) of the thin film 104 is released. As a result, as shown in the schematic cross-sectional view of FIG. 21, there is a problem that the base stabilizing thin film 104 is peeled off and cannot be used as a superconducting wire.

  In the production of RE123-based superconducting wires, it is required to eliminate the above problems as much as possible to improve the yield of superconducting wires and to reduce the production cost.

  In view of the above circumstances, an object of the present invention is to provide a superconducting wire and a method of manufacturing a superconducting wire that can improve the yield of the superconducting wire and reduce the manufacturing cost.

The present invention includes a metal substrate, an intermediate layer disposed on the metal substrate, a superconducting layer disposed on the intermediate layer, a first silver stabilizing layer disposed on the superconducting layer, an intermediate layer between the metal substrate and the intermediate layer. A second silver stabilizing layer covering at least a part of the outer surface of the laminate including the layer, the superconducting layer, and the first silver stabilizing layer; and at least a part of the outer surface of the second silver stabilizing layer. A superconducting wire comprising a covering copper stabilizing layer, wherein the second silver stabilizing layer covers at least a side surface of the laminate .

The present invention also includes a step of forming an intermediate layer on a metal substrate, a step of forming a superconducting layer on the intermediate layer, a step of forming a first silver stabilizing layer on the superconducting layer, Forming a second silver stabilizing layer covering at least a part of the outer surface of the laminate including the intermediate layer, the superconducting layer, and the first silver stabilizing layer; and the outer surface of the second silver stabilizing layer the look-containing and forming a copper stabilization layer overlying at least a portion, and, forming a second silver stabilization layer, the second silver stabilization layer to cover at least the side surface of laminate It is a manufacturing method of the superconducting wire to be formed .

In the method for producing a superconducting wire of the present invention, in the step of forming the second silver stabilizing layer, the second silver stabilizing layer is preferably formed by electroplating. Here, the second silver stabilizing layer is preferably formed using a neutral cyan bath. The second silver stabilizing layer is preferably formed at a current density of 10 A / dm ² or more.

  In the method for producing a superconducting wire of the present invention, in the step of forming the first silver stabilizing layer, the first silver stabilizing layer can be formed by physical vapor deposition.

  Moreover, in the manufacturing method of the superconducting wire of this invention, it is preferable to include the process of slit-processing a laminated body before the process of forming a 2nd silver stabilization layer.

In the method for manufacturing a superconducting wire of the present invention, the step of forming the copper stabilization layer may include a step of forming the copper stabilization layer by an electroplating method. Here, the copper stabilization layer is preferably formed at a current density of 5 A / dm ² or more.

  ADVANTAGE OF THE INVENTION According to this invention, while being able to improve the yield of a superconducting wire, the superconducting wire which can reduce manufacturing cost and the manufacturing method of a superconducting wire can be provided.

(A) is a typical top view of an example of the superconducting wire of the present invention, and (b) is a typical sectional view along 1b-1b of (a). It is a flowchart of an example of the manufacturing method of the superconducting wire shown to Fig.1 (a) and FIG.1 (b). It is typical sectional drawing illustrating a part of manufacturing process of an example of the manufacturing method of the superconducting wire shown to Fig.1 (a) and FIG.1 (b). It is typical sectional drawing illustrating other one part of the manufacturing process of an example of the manufacturing method of the superconducting wire shown to Fig.1 (a) and FIG.1 (b). FIG. 10 is a schematic cross-sectional view illustrating still another part of the manufacturing process of the example of the method for manufacturing the superconducting wire shown in FIGS. 1 (a) and 1 (b). FIG. 10 is a schematic cross-sectional view illustrating still another part of the manufacturing process of the example of the method for manufacturing the superconducting wire shown in FIGS. It is a typical top view illustrating the method of slit-processing the laminated body used for the superconducting wire shown to Fig.1 (a) and FIG.1 (b). 1A and 1B illustrate an example of a method for forming a second silver stabilizing layer by electroplating on a laminate after slit processing of the laminate used in the superconducting wire shown in FIG. 1A and FIG. It is a schematic diagram. A state in which the second silver stabilizing layer is being formed by electroplating on the laminated body after slit processing of the laminated body used in the superconducting wire shown in FIG. 1 (a) and FIG. 1 (b). It is a typical sectional view illustrated. 1A and 1B illustrate the state after the second silver stabilizing layer is formed by electroplating on the laminate after slit processing of the laminate used in the superconducting wire shown in FIG. It is typical sectional drawing. (A) is a typical top view of other examples of the superconducting wire material of the present invention, and (b) is a typical sectional view which followed 11b-11b of (a). It is a flowchart of another example of the manufacturing method of the superconducting wire shown to Fig.11 (a) and FIG.11 (b). A method of forming a second silver stabilization layer and a copper stabilization layer by electroplating on the laminate after slit processing of the laminate used in the superconducting wire shown in FIGS. 11 (a) and 11 (b) It is a schematic diagram illustrating an example. It is typical sectional drawing illustrating a part of manufacturing process of the manufacturing method of the conventional RE123 type superconducting wire. It is typical sectional drawing illustrating other one part of the manufacturing process of the manufacturing method of the conventional RE123 type superconducting wire. It is typical sectional drawing illustrating still another one part of the manufacturing process of the manufacturing method of the conventional RE123 type superconducting wire. It is typical sectional drawing illustrating still another one part of the manufacturing process of the manufacturing method of the conventional RE123 type superconducting wire. It is a schematic plan view illustrating a method of slitting a conventional RE123-based superconducting wire. It is typical sectional drawing illustrating the method of slitting the element conductor used for preparation of the conventional RE123 type superconducting wire with a gang slitter. It is typical sectional drawing before forming a stabilization layer by the electroplating method on the outer surface of the elementary conductor used for preparation of the conventional RE123 type superconducting wire. FIG. 6 is a schematic cross-sectional view illustrating a state in which an underlying stabilization thin film has been peeled off when a stabilization layer is formed on the outer surface of an element conductor used for manufacturing a conventional RE123-based superconducting wire by electroplating.

  Embodiments of the present invention will be described below. In the drawings of the present invention, the same reference numerals represent the same or corresponding parts.

<Embodiment 1>
FIG. 1 (a) shows a schematic plan view of an example of the superconducting wire of the present invention, and FIG. 1 (b) shows the superconducting wire shown in FIG. 1 (a) along 1b-1b of FIG. 1 (a). A schematic cross-sectional view is shown.

  Here, as shown in FIG. 1A, the superconducting wire 10 of the present invention has a tape-like shape. Moreover, as shown in FIG.1 (b), the superconducting wire 10 is the 1st silver stabilization layer 4a, the metal substrate 1 installed on the surface of the 1st silver stabilization layer 4a, and the metal substrate 1 The intermediate layer 2 installed on one surface of the substrate, the superconducting layer 3 installed on the surface of the intermediate layer 2, and the first silver stabilizing layer 4a installed on the surface of the superconducting layer 3 are It has the laminated body laminated | stacked in order, It has the structure by which the 2nd silver stabilization layer 4b was formed so that the outer surface of this laminated body might be covered.

  FIG. 2 shows a flowchart of an example of a method for manufacturing the superconducting wire 10 shown in FIGS. 1 (a) and 1 (b). Hereinafter, an example of a method of manufacturing the superconducting wire 10 shown in FIGS. 1A and 1B will be described along the flowchart of FIG.

  First, in step S1a, the intermediate layer 2 is formed on the surface of the metal substrate 1. Here, the intermediate layer 2 can be formed on the surface of the metal substrate 1, for example, as shown in the schematic cross-sectional view of FIG.

  As the metal substrate 1, for example, a tape-shaped conductive substrate made of an alloy containing nickel as a main component can be used. Especially, as the metal substrate 1, it is preferable to use an alloy containing nickel as a main component, and in particular, the alloy containing nickel as a main component preferably contains tungsten. In the present invention, the “main component” means 50% or more of the total number of atoms constituting the metal substrate.

  Further, the thickness of the metal substrate 1 is not particularly limited, but may be, for example, 80 μm or more and 120 μm or less.

  Further, as the intermediate layer 2, for example, a cerium oxide layer, a yttria-stabilized zirconia layer (YSZ layer), a GdZrO layer made of gadolinia and zirconia, and at least one ceramic layer selected from the group of magnesium oxide layers, etc. Can be used.

  In particular, as the intermediate layer 2, it is preferable to use a three-layer laminate in which the cerium oxide layer, the YSZ layer, and the cerium oxide layer are laminated in this order from the metal substrate 1 side. In this case, for example, the thickness of the YSZ layer can be set to 0.3 μm or less, and the thickness of the cerium oxide layers disposed on both sides of the YSZ layer can be set to 0.1 μm or less, respectively.

The YSZ layer can be represented by the following composition formula (1).
(ZrO ₂ ) _1-x (Y ₂ O ₃ ) _x (1)
In the composition formula (1), 1-x represents a composition ratio of ZrO ₂ (zirconia), and x represents a composition ratio of Y ₂ O ₃ (yttria). In the composition formula (1), x is a real number that satisfies 0.03 ≦ x ≦ 0.1.

  The intermediate layer 2 can be formed by, for example, at least one method selected from the group consisting of sputtering, laser ablation, electron beam evaporation, and IBAD (Ion Beam Assist Deposition).

  Next, in step S2a, the superconducting layer 3 is formed on the surface of the intermediate layer 2. Here, the superconducting layer 3 can be formed on the surface of the intermediate layer 2 on the metal substrate 1, for example, as shown in the schematic cross-sectional view of FIG.

  As the superconducting layer 3, for example, a RE123-based superconductor which is a RE-Ba-Cu-O-based oxide superconductor can be used. Note that RE is a rare earth element (lanthanum (La), neodymium (Nd), samarium (Sm), gadolinium (Gd), holmium (Ho), yttrium (Y), dysprosium (Dy), erbium (Er), thulium (Tm). ), At least one selected from the group consisting of ytterbium (Yb) and ruthenium (Lu), Ba represents barium, Cu represents copper, and O represents oxygen.

  Here, the composition of the RE-Ba-Cu-O-based oxide superconductor can be expressed by the following composition formula (2).

RE _a Ba _{B c c} O _d (2)
In the above composition formula (2), a represents the composition ratio of rare earth elements, b represents the composition ratio of barium, c represents the composition ratio of copper, and d represents the composition ratio of oxygen. In the composition formula (2), a is a real number that satisfies 0.7 ≦ a ≦ 1.3, b is a real number that satisfies 1.7 ≦ b ≦ 2.3, and c is 2.7. ≦ c ≦ 3.3 is a real number, and d is a real number that satisfies 6 ≦ d ≦ 8. Among the RE-Ba-Cu-O-based oxide superconductors, the superconducting layer 3 is Ho-Ba-Cu- whose composition is represented by a composition formula in which RE in the composition formula (2) is Ho. It is preferable to use an O-based oxide superconductor.

  Further, the superconducting layer 3 is formed by, for example, at least one method selected from the group consisting of sputtering, laser ablation, MOD (Metal Organic Deposition), and MOCVD (Metal Organic Chemical Vapor Deposition). Can do.

  Next, in step S3a, the first silver stabilizing layer 4a is formed on the surface of the superconducting layer 3. Here, the first silver stabilizing layer 4a can be formed on the surface of the superconducting layer 3 as shown in the schematic cross-sectional view of FIG.

  The first silver stabilizing layer 4a on the surface of the superconducting layer 3 can be formed, for example, by forming a film made of silver on the superconducting layer 3 using a physical vapor deposition method such as a sputtering method. .

  The thickness of the first silver stabilizing layer 4a on the surface of the superconducting layer 3 is not particularly limited, but is preferably formed to a thickness of 8 μm or less, for example. When the thickness of the first silver stabilizing layer 4a is formed to be thicker than 8 μm, the production cost tends to be increased by using a large amount of silver for forming the first silver stabilizing layer 4a. Due to the low mechanical strength, there is a tendency that sufficient mechanical strength of the superconducting wire cannot be obtained.

  The thickness of the first silver stabilizing layer 4a on the surface of the superconducting layer 3 is not particularly limited, but is preferably formed to a thickness of 2 μm or more, for example. When the thickness of the first silver stabilizing layer 4a on the surface of the superconducting layer 3 is formed to be thinner than 2 μm, the protection of the superconducting layer 3 may be insufficient. Therefore, for the above reason, the thickness of the silver stabilizing layer 4 is preferably 2 μm or more and 8 μm or less.

  Next, in step S4a, a first silver stabilizing layer 4a is formed on the back surface, which is the surface opposite to the installation side of the intermediate layer 2 of the metal substrate 1. Here, the first silver stabilizing layer 4a is formed on the back surface which is the surface opposite to the installation side of the intermediate layer 2 of the metal substrate 1, as shown in the schematic cross-sectional view of FIG. Can do. Thereby, the laminated body 6 in which the first silver stabilizing layer 4a, the metal substrate 1, the intermediate layer 2, the superconducting layer 3, and the first silver stabilizing layer 4a are laminated in this order is formed.

  Next, in step S5a, the outer surface of the laminated body 6 in which the first silver stabilizing layer 4a, the metal substrate 1, the intermediate layer 2, the superconducting layer 3, and the first silver stabilizing layer 4a are laminated in this order. A second silver stabilizing layer 4b is formed so as to cover.

  Here, before forming the 2nd silver stabilization layer 4b, it is preferable that said laminated body 6 is slit-processed. For example, as shown in the schematic plan view of FIG. 7, the slit processing of the laminated body 6 is performed by cutting the laminated body 6 along the longitudinal direction of the laminated body 6 to reduce the width and the ears of the laminated body. This can be done by dividing into 6b. In addition, as a method of cut | disconnecting the laminated body 6, there exists the method of using the conventionally well-known gang slitter demonstrated above, for example.

  The second silver stabilizing layer 4b is formed by electroplating so as to cover the outer surface of the laminate 6 described above. Here, the 2nd silver stabilization layer 4b can be formed as shown, for example in the schematic diagram of FIG.

  First, the laminated body 6a after the slit processing is spanned between the first roll 7a and the second roll 7b.

  Next, after unwinding the laminated body 6a from the first roll 7a, the laminated body 6a is immersed in the silver plating solution 9 accommodated in the silver plating tank 8, and the outer surface of the laminated body 6a is obtained by electroplating. Then, silver is deposited from the silver plating solution 9 so as to cover the surface, and the second silver stabilizing layer 4b is formed to form the superconducting wire 10.

  Thereafter, the superconducting wire 10 formed by covering the outer surface of the laminate 6a with the second silver stabilizing layer 4b is wound around the second roll 7b and collected.

  As described above, the superconducting wire 10 of the present invention shown in FIGS. 1A and 1B is manufactured.

  Here, the electroplating method is, for example, by applying a positive potential to the electrode immersed in the silver plating solution 9 and applying a negative potential to the laminate 6a immersed in the silver plating solution 9. This can be done by forming an electric field between the electrode in the silver plating solution 9 and the laminate 6a.

  In the present invention, before the end of the superconducting layer 3 is dissolved in the silver plating solution 9 and the first silver stabilizing layer 4a is peeled off, the outer surface of the laminate 6a is covered by electroplating. The second silver stabilizing layer 4b is formed. For this purpose, the formation rate of the second silver stabilization layer 4b by electroplating is required to be faster than the dissolution rate of the superconducting layer 3.

  For example, as shown in the schematic cross-sectional view of FIG. 9, since the current is less likely to flow at the end of the superconducting layer 3 as compared to the metal substrate 1 and the first silver stabilizing layer 4a, It is difficult to cover with the silver stabilizing layer 4b.

  Therefore, by increasing the formation rate of the second silver stabilization layer 4b by the electroplating method than the dissolution rate of the superconducting layer 3, for example, as shown in the schematic cross-sectional view of FIG. And the second silver stabilizing layer 4b covering the first silver stabilizing layer 4a on the superconducting layer 3 are connected before the superconducting layer 3 is dissolved, The second silver stabilizing layer 4 b covers the end of the superconducting layer 3.

  Here, the silver plating solution 9 includes, for example, a conventionally known cyanide ion and silver ion capable of forming silver by electroplating to form the second silver stabilizing layer 4b. In particular, a neutral cyan bath is preferably used. When a neutral cyan bath is used as the silver plating solution 9, there is a greater tendency that the second silver stabilizing layer 4b can be formed while the dissolution of the superconducting layer 3 is suppressed. The neutral cyan bath means a plating solution containing cyanide ions and silver ions and having a pH of 8 or more and 9 or less.

  In addition, conventionally well-known additives, such as a smoothing agent, may be suitably added to the silver plating solution 9, for example.

Further, in the formation of the second silver stabilization layer 4b by electroplating, a second silver stabilization layer 4b is preferably formed of a 10A / dm ² or more current density, 15A / dm ² or more current More preferably, it is formed with a density. When the current density at the time of forming the second silver stabilizing layer 4b by electroplating is 10 A / dm ² or more, particularly when it is 15 A / dm ² or more, the first silver by dissolution of the superconducting layer 3 is used. There is a tendency that peeling of the stabilization layer 4a can be more effectively suppressed.

  Thus, the first silver stabilization by dissolution of the superconducting layer 3 is achieved by making the formation rate of the second silver stabilization layer 4b by electroplating faster than the dissolution rate of the superconducting layer 3 by the silver plating solution 9. Since the peeling of the layer 4a can be suppressed, the yield of the superconducting wire 10 can be improved.

  Furthermore, since the formation speed of the 2nd silver stabilization layer 4b by an electroplating method can be made quick, the manufacturing cost of the superconducting wire 10 can also be reduced.

  That is, conventionally, as described in Patent Document 1, from the viewpoint of reducing the manufacturing cost of the superconducting wire, as described in Patent Document 1, as a stabilizing layer of the superconducting layer, a silver layer, A combination of copper layers made of copper that is less expensive than silver has been used. This is because copper is less expensive than silver.

  However, in the electroplating method, when the plating film having the same film thickness is formed, the silver plating film can be formed more than 10 times faster than the copper plating film, so that the first roll 7a shown in FIG. The speed from the feeding of the body 6a to the winding of the second roll 7b can be made 10 times or more.

  Thus, in the present invention, the stabilizing layer covering the outer surface of the laminate 6a is not the copper layer formed by electroplating as in Patent Document 1, but the first formed by electroplating. By using the second silver stabilizing layer 4b, the processing cost of electroplating can be reduced to about 1/10 compared with the method described in Patent Document 1.

  In other words, since the manufacturing cost of superconducting wire greatly depends on the sum of processing cost and material cost, in the present invention, even when expensive silver is used and the material cost is increased, the processing cost is greatly reduced further. By doing so, the manufacturing cost of the entire superconducting wire can be reduced.

<Embodiment 2>
In the present embodiment, the second silver stabilizing layer that covers the outer surface of the laminate in which the first silver stabilizing layer, the metal substrate, the intermediate layer, the superconducting layer, and the first silver stabilizing layer are laminated in this order. The outer surface of the crystallization layer 4b is further covered with a copper stabilization layer.

  That is, by replacing a part of the second silver stabilizing layer 4b described in the first embodiment with a copper stabilizing layer, the second reason of the present invention is the same as the reason described in the first embodiment. Compared with the method described in Patent Document 1 in which all of the portion corresponding to the silver stabilizing layer 4b is formed of a copper layer, the yield of the superconducting wire can be improved and the manufacturing cost of the superconducting wire can be reduced. it can.

  FIG. 11A shows a schematic plan view of the superconducting wire according to the present embodiment, which is another example of the superconducting wire of the present invention, and FIG. 11B is taken along 11b-11b of FIG. 11A. The typical sectional view of superconducting wire 20 shown in Drawing 11 (a) is shown.

  Here, as shown in FIG. 11A, the superconducting wire 20 of the present invention has a tape-like shape. 11B, the superconducting wire 20 includes a first silver stabilizing layer 4a, a metal substrate 1 installed on the surface of the first silver stabilizing layer 4a, and a metal substrate 1 The intermediate layer 2 installed on one surface of the substrate, the superconducting layer 3 installed on the surface of the intermediate layer 2, and the first silver stabilizing layer 4a installed on the surface of the superconducting layer 3 are It has the laminated body laminated | stacked in order, and while the 2nd silver stabilizing layer 4b is formed so that the outer surface of this laminated body may be covered, the outer surface of the 2nd silver stabilizing layer 4b is covered In this way, the copper stabilizing layer 5 is formed.

  FIG. 12 shows a flowchart of an example of a method of manufacturing the superconducting wire 20 shown in FIGS. 11 (a) and 11 (b). Hereinafter, an example of a method for manufacturing the superconducting wire 20 shown in FIGS. 11A and 11B will be described along the flowchart of FIG.

  First, after forming the intermediate layer 2 on the surface of the metal substrate 1 in step S1b, the superconducting layer 3 is formed on the surface of the intermediate layer 2 in step S2b.

  Next, after forming the first silver stabilizing layer 4a on the surface of the superconducting layer 3 in step S3b, on the back surface which is the surface opposite to the installation side of the intermediate layer 2 of the metal substrate 1 in step S4b. A first silver stabilizing layer 4a is formed.

  Next, in step S5b, the outer surface of the stacked body 6 in which the first silver stabilizing layer 4a, the metal substrate 1, the intermediate layer 2, the superconducting layer 3, and the first silver stabilizing layer 4a are stacked in this order is applied. A second silver stabilizing layer 4b is formed so as to cover.

  Also in the present embodiment, before the second silver stabilizing layer 4b is formed, the laminate 6 is preferably slit processed.

  Next, in step S6b, a copper stabilization layer 5 that covers the outer surface of the second silver stabilization layer 4b is formed. Here, the 2nd silver stabilization layer 4b and the copper stabilization layer 5 can be formed as shown, for example in the schematic block diagram of FIG.

  First, the laminated body 6a after the slit processing is spanned between the first roll 7a and the second roll 7b.

  Next, after unwinding the laminated body 6a from the first roll 7a, the laminated body 6a is immersed in the silver plating solution 9 accommodated in the silver plating tank 8, and the outer surface of the laminated body 6a is obtained by electroplating. Then, silver is deposited from the silver plating solution 9 so as to cover the surface, and the second silver stabilization layer 4b is formed.

  Subsequently, the laminated body 6a after the formation of the second silver stabilizing layer 4b is immersed in a copper plating solution 29 accommodated in the copper plating tank 28, and the second silver stabilizing layer 4b is electroplated. The copper stabilization layer 5 is formed by depositing copper from the copper plating solution 29 so as to cover the outer surface.

  Thereafter, the superconducting wire 20 formed by covering the outer surface of the second silver stabilizing layer 4b with the copper stabilizing layer 5 is wound around the second roll 7b and collected.

  As described above, the superconducting wire 20 of the present invention shown in FIGS. 11A and 11B is manufactured.

  Here, the copper stabilization layer 5 applies, for example, a positive potential to the electrode immersed in the copper plating solution 29, and after the formation of the second silver stabilization layer 4b immersed in the copper plating solution 29. By applying a negative potential to the laminate, an electric field can be formed between the electrode in the copper plating solution 29 and the laminate.

  Here, as the copper plating solution 29, for example, one capable of forming copper stabilization layer 5 by depositing copper by electroplating can be used. From the viewpoint of formation, it is preferable to use an aqueous solution of copper sulfate pentahydrate and sulfuric acid.

  In addition, conventionally well-known additives, such as a brightener, may be suitably added to the copper plating solution 29, for example.

In forming the copper stabilization layer 5 by electroplating, the copper stabilization layer 5 is preferably formed at a current density of 5 A / dm ² or more, and preferably formed at a current density of 10 A / dm ² or more. Is more preferable. When the current density during the formation of the copper stabilization layer 5 by electroplating is 5 A / dm ² or more, particularly 10 A / dm ² or more, the manufacturing cost of the superconducting wire 20 can be greatly reduced. There is a tendency.

  Since the description other than the above in the present embodiment is the same as that in the first embodiment, the description thereof is omitted.

Example 1
First, an oriented metal substrate made of a tape-like nickel-tungsten alloy having a width of 10 mm, a length of 100 m, and a thickness of 0.1 mm was prepared. Here, in the metal substrate, nickel occupied 95% of the total number of atoms constituting the metal substrate, and tungsten accounted for 5% of the total number of atoms constituting the metal substrate.

Next, a first cerium oxide layer having a thickness of 0.1 μm was formed on the metal substrate by RF sputtering. Subsequently, a YSZ layer having a thickness of 0.3 μm was formed on the first cerium oxide layer by RF sputtering. Further, a second cerium oxide layer having a thickness of 0.1 μm was formed on the YSZ layer by RF sputtering. Thus, an intermediate layer composed of a three-layered structure in which the first cerium oxide layer, the YSZ layer, and the second cerium oxide layer were stacked in this order from the substrate side was formed on the substrate. Here, the YSZ layer was a solid solution of ZrO ₂ and Y ₂ O ₃ represented by a composition formula of (ZrO ₂ ) _0.92 (Y ₂ O ₃ ) _0.08 .

Next, a Ho—Ba—Cu—O-based oxide having a composition represented by the composition formula of HoBa ₂ Cu ₃ O _7-δ satisfying the above composition formula (2) is formed on the intermediate layer by a pulse laser deposition method. A superconducting layer having a thickness of 1 μm made of a superconductor was formed.

  Then, a first silver stabilizing layer having a thickness of 3 μm was formed on the superconducting layer by DC sputtering.

  Next, a first silver stabilizing layer having a thickness of 3 μm was also formed on the surface of the metal substrate opposite to the side where the intermediate layer was placed by DC sputtering.

  Thereafter, a tape-like laminate 6 having a width of 10 mm in which the first silver stabilizing layer, the metal substrate, the intermediate layer, the superconducting layer, and the first silver stabilizing layer are laminated in this order is formed using a gang slitter. A slit-shaped laminate 6a having a width of 2 mm was obtained by slitting as shown in FIG.

  And as shown in FIG. 8, using the electroplating apparatus provided with the 1st roll 7a for feeding, the silver plating tank 8 in which the silver plating solution 9 was accommodated, and the 2nd roll 7b for winding, The superconductivity of Example 1 is formed by depositing silver on the outer surface of the first silver stabilizing layer of the laminate 6a by electroplating to form a second silver stabilizing layer made of a 20 μm thick silver plating film. A wire rod 10 was produced.

  Here, as the silver plating solution 9, an aqueous solution having the composition shown in Table 1 below was used, and as the smoothing agent shown in Table 1, one having the composition shown in Table 2 below was used. In addition, the numerical value in Table 1 has shown content (g / l) with respect to 1 liter of water of each component which comprises the silver plating solution 9, and the numerical value in Table 2 shows each component which comprises a smoothing agent. The mass ratio is shown.

In addition, the formation of the second silver stabilizing layer by the electroplating method described above is such that the current density on the outer surface of the first silver stabilizing layer of the laminate 6a to be the negative electrode is 10 A / dm ² or more and 20 A / dm ² or less. The current amount is adjusted so as to be in the range, and the temperature of the silver plating solution 9 (pH = 8-9) that is a neutral cyan bath is 45 ° C. This was performed by passing a current between the outer surface of the stabilization layer and the positive electrode immersed in the silver plating solution 9.

  And when it checked visually about whether the 1st silver stabilization layer of superconducting wire material 10 of the above-mentioned example 1 had peeled off, the 1st silver stabilization layer did not peel.

  Therefore, in the formation of the superconducting wire 10 of Example 1, the second silver stabilizing layer could be formed by electroplating before the superconducting layer was dissolved in the silver plating solution 9.

(Example 2)
As shown in FIG. 13, a first roll 7a for feeding, a silver plating tank 8 containing a silver plating solution 9, a copper plating tank 28 containing a copper plating solution 29, and a second roll for winding. The second silver stabilization comprising a silver plating film having a thickness of 18 μm by depositing silver on the outer surface of the first silver stabilization layer of the laminate 6a by electroplating using an electroplating apparatus having 7b In addition to forming a layer and depositing copper on the outer surface of the second silver stabilizing layer to form a copper stabilizing layer made of a copper plating film having a thickness of 2 μm, the same as in Example 1, A superconducting wire 20 of Example 2 was produced.

  Here, as the silver plating solution 9, an aqueous solution having the composition shown in Table 1 was used, and as the smoothing agent shown in Table 1, one having the composition shown in Table 2 was used.

  As the copper plating solution 29, an aqueous solution having the composition shown in Table 3 below was used, and as the brightener shown in Table 3, conventionally known brighteners were used. In addition, the numerical value in Table 1 has shown content (g / l) with respect to 1 liter of water of each component which comprises the copper plating solution 29. FIG.

In addition, the formation of the second silver stabilizing layer by the electroplating method described above is such that the current density on the outer surface of the first silver stabilizing layer of the laminate 6a to be the negative electrode is 10 A / dm ² or more and 20 A / dm ² or less. The first current of the laminate 6a to be the negative electrode is adjusted under the condition that the temperature of the silver plating solution 9 (pH = 8 to 9) as a neutral cyan bath is 45 ° C. This was performed by passing a current between the outer surface of the silver stabilizing layer and the positive electrode immersed in the silver plating solution 9.

Further, the formation of the copper stabilization layer by the above electroplating method is performed by adjusting the amount of current so that the current density on the outer surface of the second silver stabilization layer to be the negative electrode is 5 A / dm ² , This was performed by passing a current between the outer surface of the second silver stabilizing layer serving as the negative electrode and the positive electrode immersed in the copper plating solution 29 under the condition that the temperature of the liquid 29 was 25 ° C.

  And when it checked visually about whether the 1st silver stabilization layer of superconducting wire 20 of the above-mentioned example 2 had peeled off, the 1st silver stabilization layer did not peel.

  Therefore, also in the formation of the superconducting wire 20 of Example 2, the second silver stabilizing layer could be formed by electroplating before the superconducting layer was dissolved in the silver plating solution 9.

(Comparative Example 1)
A superconducting wire of Comparative Example 1 was produced in the same manner as in Example 1 except that an aqueous solution having the composition shown in Table 4 below was used as the silver plating solution 9 and the electroplating conditions in the electroplating method were changed. As the brighteners shown in Table 4, those containing conventionally known antimony and selenium were used.

In addition, the formation of the second silver stabilizing layer by the electroplating method described above is such that the current density on the outer surface of the first silver stabilizing layer of the laminate 6a to be the negative electrode is 5 A / dm ² or more and less than 10 A / dm ^2. The outer surface of the first silver stabilization layer 6a to be the negative electrode under the condition that the amount of current is adjusted so that the temperature of the silver plating solution 9 (pH = 11) is 42 to 45 ° C. And a positive electrode immersed in the silver plating solution 9 by passing a current.

  And when it checked visually whether the 1st silver stabilization layer of the superconducting wire of comparative example 1 had peeled, it was confirmed that the 1st silver stabilization layer had peeled. It was.

  Therefore, in the formation of the superconducting wire of Comparative Example 1, the superconducting layer was dissolved before the second silver stabilizing layer was formed by electroplating.

(Evaluation)
Table 5 below summarizes the relationship between the electroplating conditions and the presence or absence of peeling of the first silver stabilizing layer in the production of the respective superconducting wires of Example 1, Example 2 and Comparative Example 1.

  As shown in Table 5, under the silver plating conditions in the production of the superconducting wires of Example 1 and Example 2, the second silver stabilizing layer could be formed by performing silver plating faster than the dissolution rate of the superconducting layer. However, silver plating could not be performed faster than the dissolution rate of the superconducting layer under the silver plating conditions in the production of the superconducting wire of Comparative Example 1.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The superconducting wire of the present invention includes, for example, a superconducting cable, a superconducting motor, a generator, a magnetic separation device, a magnet for a single crystal pulling furnace, MRI (Magnetic Resonance Imaging), NMR (Nuclear Magnetic Resonance), a linear motor car or a transformer. There is a possibility that it can be used for superconducting equipment.

  1 metal substrate, 2 intermediate layer, 3 superconducting layer, 4a first silver stabilizing layer, 4b second silver stabilizing layer, 5 copper stabilizing layer, 6, 6a laminate, 6b ear, 7a first Roll, 7b Second roll, 8 Silver plating tank, 9 Silver plating solution, 10, 20 Superconducting wire, 28 Copper plating tank, 29 Copper plating bath, 101 Base material, 102 Intermediate layer, 103 Oxide superconducting layer, 104 Base Stabilized thin film, 105 Stabilized layer, 106 Element conductor, 106a Element conductor body part, 106b Element conductor ear part, 107a Block upper blade, 107b Block lower blade.

Claims (9)

A metal substrate;
An intermediate layer installed on the metal substrate;
A superconducting layer installed on the intermediate layer;
A first silver stabilizing layer disposed on the superconducting layer;
A second silver stabilizing layer covering at least a part of the outer surface of the laminate including the metal substrate, the intermediate layer, the superconducting layer, and the first silver stabilizing layer ;
A copper stabilization layer covering at least part of the outer surface of the second silver stabilization layer,
The superconducting wire, wherein the second silver stabilizing layer covers at least a side surface of the laminate . Forming an intermediate layer on a metal substrate;
Forming a superconducting layer on the intermediate layer;
Forming a first silver stabilizing layer on the superconducting layer;
Forming a second silver stabilizing layer covering at least a part of the outer surface of the laminate including the metal substrate, the intermediate layer, the superconducting layer, and the first silver stabilizing layer;
Forming a copper stabilization layer overlying at least a portion of the outer surface of the second silver stabilization layer, only including,
The method of forming the second silver stabilizing layer includes a step of forming the second silver stabilizing layer so as to cover at least a side surface of the laminate . In the step of forming the second silver stabilization layer, said second silver stabilization layer is characterized by being formed by electroplating method of manufacturing a superconducting wire according to claim 2. 4. The method of manufacturing a superconducting wire according to claim 3 , wherein in the step of forming the second silver stabilizing layer, the second silver stabilizing layer is formed using a neutral cyan bath. 5. Method. In the step of forming the second silver stabilization layer, said second silver stabilization layer is characterized by being formed by 10A / dm ² or more current density, according to claim 3 or 4 Manufacturing method of superconducting wire. In the step of forming the first silver stabilization layer, the first silver stabilization layer is characterized by being formed by a physical vapor deposition, according to claims 2 to any one of 5 Manufacturing method of superconducting wire. The method of manufacturing a superconducting wire according to any one of claims 2 to 6 , further comprising a step of slitting the stacked body before the step of forming the second silver stabilizing layer. The method for producing a superconducting wire according to any one of claims 2 to 7 , wherein the step of forming the copper stabilization layer includes a step of forming the copper stabilization layer by electroplating. . The method for producing a superconducting wire according to claim 8 , wherein in the step of forming the copper stabilization layer, the copper stabilization layer is formed at a current density of 5 A / dm ² or more.

Images