Method and apparatus for plating superconducting wire rod

Abstract

Provided are a method and an apparatus for plating a superconducting wire rod, the method and apparatus making it possible to form a plating layer while suppressing the dog bone effect on the surface of a superconducting wire rod by electroplating, through a method different from a conventional method. Provided is a method for plating a superconducting wire rod, the method including forming a copper plating layer 11 by performing electroplating on the surface of a tape-shaped superconducting wire rod 10 that includes a superconductor layer, wherein the electroplating is performed in a state in which a plurality of superconducting wire rods 10 are arranged in parallel at intervals from each other on the same plane 50.

Description

Superconducting wire plating method and plating apparatus

[0001] The present invention relates to a method and apparatus for plating a superconducting wire.

[0002] Conventionally, a technique for forming a copper plating layer on the surface of a superconducting wire by electroplating has been known (see, for example, Non-Patent Documents 1 and 2). Electroplating can be performed at a lower cost than physical deposition methods.

[0003] However, electroplating can cause a phenomenon known as "dogbone," in which the electric field concentrates at the edges of the superconducting wire, causing the plating layer to thicken at those edges. The occurrence of dogbone causes the shape of the superconducting wire to become non-uniform, making it difficult to use the superconducting wire in superconducting coils or cables, where precision and packing density are important.

[0004] Non-Patent Document 1 discusses a parallel shield method to suppress dog-bone formation. Non-Patent Document 2 discloses another method for suppressing dog-bone formation, which is to use a Cu cathode near the superconducting wire to shield the electric field.

[0005] Abraimov D, Ballarino A, Barth C, Bottura L, Dietrich R, Francis A, Jaroszynski J, Majkic GS, McCallister J, Polyanskii A, Rossi L. Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field. Superconductor Science and Technology. 2015 Oct 9;28(11):114007.Floegel-Delor U, Riedel T, Rothfeld R, Schirrmeister P, Koenig R, Werfel FN. High-efficient copper shunt deposition technology on REBCO tape surfaces. IEEE Transactions on Applied Superconductivity. 2016 Apr 1;26(3):1-5.

[0006] An object of the present invention is to provide a plating method and plating apparatus for superconducting wire that is different from conventional methods and that can form a plating layer on the surface of superconducting wire by electroplating while suppressing dog bones.

[0007] In order to achieve the above object, one aspect of the present invention provides the following plating method and plating apparatus for a superconducting wire.

[0008] [1] A method for plating superconducting wire, in which a copper plating layer is formed by electroplating the surface of a tape-shaped superconducting wire including a superconductor layer, wherein the electroplating is performed on a plurality of the superconducting wires arranged in parallel with a gap between them on the same plane. [2] The method for plating superconducting wire according to [1] above, wherein the gap is 0.3 mm or more and is equal to or less than the width of the superconducting wire. [3] The method for plating superconducting wire according to [1] or [2] above, wherein the plurality of superconducting wires are parts of a single superconducting wire wound in a spiral shape. [4] The method for plating superconducting wire according to [3] above, wherein the number of the plurality of superconducting wires is 3 or more. [5] A plating apparatus used for electroplating a superconducting wire, comprising: a treatment tank containing a plating solution; an electrode disposed in the plating solution; and a plurality of guide reel assemblies each including a plurality of stacked guide reels that guide the transport of the superconducting wire, wherein the superconducting wire is wound around the plurality of guide reel assemblies, and a voltage is applied between the superconducting wire and the electrode in the plating solution, with a plurality of strip-shaped portions that are parts of the wound superconducting wire being aligned parallel to one another at intervals on the same plane, to form a copper plating layer on the surface of the superconducting wire. [6] The plating apparatus described in [5] above, wherein the interval is 0.3 mm or more and is equal to or less than the width of the superconducting wire. [7] The plating apparatus described in [5] or [6] above, wherein the plurality of guide reel assemblies can wind the superconducting wire three or more times. [8] The plating apparatus described in [5] or [6] above, wherein the plurality of guide reel assemblies include a contact reel installed outside the plating solution that supplies current to the superconducting wire, and the wound superconducting wire contacts the contact reel at each turn, so that an equal potential is supplied to each turn portion.

[0009] According to the present invention, a plating method and plating apparatus for superconducting wire can be provided that, by a method different from conventional methods, can form a plating layer on the surface of superconducting wire by electroplating while suppressing dog bones.

[0010] FIG. 1A is a perspective view schematically illustrating the structure of a superconducting wire according to an embodiment of the present invention. FIG. 1B is a vertical cross-sectional view in the width direction schematically illustrating the structure of a superconducting wire according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating the position of a superconducting wire in a plating solution contained in a treatment tank of a plating apparatus in a method for plating a superconducting wire according to an embodiment of the present invention. The upper cross-sectional view of FIG. 3 is a vertical cross-sectional view in the width direction of a single superconducting wire with no other superconducting wires present on either side. The lower graph of FIG. 3 is a graph illustrating the electric field distribution during electroplating on a plane on which the single superconducting wire shown in the upper cross-sectional view is placed, calculated by finite element method modeling. FIG. 4 is a vertical cross-sectional view in the width direction of a superconducting wire in which a dogbone has occurred. FIG. 5A is a scanning electron microscope (SEM) image illustrating the shape of a copper plating layer near one end of a single superconducting wire obtained by electroplating the single superconducting wire shown in the cross-sectional view of FIG. 3. Fig. 5B is an SEM image showing the shape of a copper plating layer near the center of a single superconducting wire obtained by electroplating the superconducting wire shown in the cross-sectional view of Fig. 3. Fig. 5C is an SEM image showing the shape of a copper plating layer near the other end of the superconducting wire obtained by electroplating the single superconducting wire shown in the cross-sectional view of Fig. 3. The upper cross-sectional view of Fig. 6 is a vertical cross-sectional view in the width direction of three superconducting wires arranged in parallel and spaced apart on the same plane. The lower graph of Fig. 6 is a graph showing the electric field distribution when electroplating is performed on a plane on which the three superconducting wires shown in the cross-sectional view of the upper side are placed, calculated by finite element method modeling. FIG. 7A is an SEM observation image showing the shape of a copper plating layer near one end of a superconducting wire obtained by electroplating a superconducting wire in a state where other superconducting wires are present on both sides, such as the superconducting wire located in the center shown in the cross-sectional view of FIG. 6 .Fig. 7B is an SEM image showing the shape of a copper plating layer near the center of a superconducting wire obtained by electroplating a superconducting wire in a state where other superconducting wires are present on both sides, such as the superconducting wire located at the center in the cross-sectional view of Fig. 6. Fig. 7C is an SEM image showing the shape of a copper plating layer near the other end of a superconducting wire obtained by electroplating a superconducting wire in a state where other superconducting wires are present on both sides, such as the superconducting wire located at the center in the cross-sectional view of Fig. 6. Fig. 8A is a schematic diagram showing the configuration of a plating apparatus for electroplating a superconducting wire. Fig. 8B is a perspective view of a guide reel assembly.

[0011] 1A and 1B are a perspective view and a vertical cross-sectional view in the width direction, respectively, schematically illustrating the structure of a superconducting wire 1 according to an embodiment of the present invention. Here, a superconducting wire 10 having a copper plating layer 11 formed on its surface is referred to as a superconducting wire 1.

[0012] The superconducting wire 10 is a tape-shaped wire having a superconductor layer for passing a superconducting current. The superconductor layer included in the superconducting wire 10 is, for example, REBa. ２ Cu ３ O ６＋ｙ The layer is mainly composed of a REBCO superconductor having a composition expressed by (0≦y≦1) (RE is a rare earth element).

[0013] In the superconducting wire 10, a superconductor layer is formed on a tape-shaped substrate made of an alloy or metal such as Hastelloy (registered trademark) via a buffer layer, etc. More specifically, the superconducting wire 10 has a structure in which a Hastelloy substrate having a thickness of 10 to 100 μm, a multilayer oxide buffer layer having a highly selectively oriented uppermost layer, an epitaxial superconducting film as a superconductor layer, and an Ag film as a protective layer are stacked.

[0014] The width of the superconducting wire 1 is, for example, 1 to 12 mm, and the thickness of the superconducting wire 1 is, for example, 30 to 150 μm.

[0015] Copper plating layer 11 is a layer made of copper formed on the surface of superconducting wire 10 by a plating method according to an embodiment of the present invention, which will be described later. Copper plating layer 11 typically covers the entire surface of superconducting wire 10, i.e., the main surfaces (upper and lower surfaces in FIG. 1B ) and side surfaces (left and right surfaces in FIG. 1B ) of superconducting wire 10. The thickness of copper plating layer 11 is, for example, 3 to 40 μm.

[0016] The copper plating layer 11 is electrically connected to the superconducting wire 10, and when the superconductor layer of the superconducting wire 10 transitions from a superconducting state to a normal conducting state, heat generation can be suppressed by passing an electric current through the copper plating layer 11, which has a higher conductivity than the superconducting wire 10.

[0017] Copper plating layer 11 may be formed on the surface of superconducting wire 10 via a conductive underlayer. The underlayer may be, for example, a metal film formed by sputtering or the like.

[0018] (Method for plating superconducting wire) Figure 2 is a schematic diagram showing the position of superconducting wire 10 in plating solution (electrolyte) 20 contained in treatment tank 21 of plating device 2 in a method for plating superconducting wire relating to an embodiment of the present invention.

[0019] The method for plating a superconducting wire according to an embodiment of the present invention is a method for electroplating the surface of a tape-shaped superconducting wire 10 including a superconductor layer to form a copper plating layer 11. As shown in Fig. 2, the electroplating is performed in a state where a plurality of superconducting wires 10 are arranged in parallel with a gap between them on the same plane 50. When electroplating is performed, the same potential is supplied to the plurality of superconducting wires 10.

[0020] By electroplating a plurality of superconducting wires 10 arranged parallel to one another on the same plane 50, electric field concentration at the edge portions (ends in the width direction) of the superconducting wires 10 is alleviated, improving the uniformity of the electric field distribution on the surface of the superconducting wires 10. As a result, dog bones are suppressed, and the thickness of the copper plating layer 11 formed on the surface of the superconducting wires 10 is improved in uniformity.

[0021] In addition, when the above-mentioned electroplating is performed, the multiple superconducting wires 10 may each be independent wires, or may be part of a single superconducting wire (superconducting wire 100 described later) that is spirally wound using a guide reel assembly or the like, as described later.

[0022] When electroplating is performed, the distance D between the multiple superconducting wires 10 arranged on the same plane 50 is, for example, 0.3 mm or more and the width W of the superconducting wires 10 or less. If the distance is 0.3 mm or more, contact between the copper plating layers 11 of adjacent superconducting wires 10 can be effectively prevented. Furthermore, if the distance is the width W of the superconducting wires 10 or less, electric field concentration at the edge portions of the superconducting wires 10 can be effectively alleviated, and dog-bone formation can be suppressed. The width W of the superconducting wires 10 is, for example, 1 mm or more. Furthermore, in practice, the distance D is more preferably 0.5 mm or more and 2 mm or less.

[0023] Note that the phrase "superconducting wires 10 are on the same plane" not only means that the main surfaces of the superconducting wires 10 are on the exact same plane, but also includes a state in which the main surfaces of the superconducting wires 10 are unintentionally slightly misaligned from the same plane due to the precision of the dimensions and arrangement of the device. For example, if the superconducting wires 10 intersect on the same plane and the angle (acute angle) between the main surfaces of the superconducting wires 10 and the same plane is of a magnitude (preferably 0.5° or less) that does not significantly affect the effect of suppressing dog-bone formation, then the superconducting wires 10 are considered to be on the same plane.

[0024] Furthermore, the phrase "superconducting wires 10 are arranged parallel to one another" not only means that the length directions of the superconducting wires 10 are completely parallel to one another, but also includes a state in which the superconducting wires 10 are unintentionally slightly deviated from parallel due to the precision of the dimensions and arrangement of the device. For example, if the angle (acute angle) formed by the length directions of adjacent superconducting wires 10 is a size (preferably 0.6° or less) that does not significantly affect the effect of suppressing dog bones, the superconducting wires 10 are considered to be arranged parallel to one another.

[0025] The upper cross-sectional view of Figure 3 is a vertical cross-sectional view in the width direction of a single superconducting wire 10 with no other superconducting wires 10 present on either side, and the lower graph of Figure 3 is a graph showing the electric field distribution when electroplating is performed on a plane 50 on which the single superconducting wire 10 shown in the upper cross-sectional view is placed, calculated by finite element method modeling.

[0026] The position [mm] on the horizontal axis of the graph in Fig. 3 corresponds to the position on plane 50 in the width direction of superconducting wire 10 shown in the upper cross-sectional view. Here, width W of a single superconducting wire 10 shown in the cross-sectional view of Fig. 3 is 4 mm.

[0027] The graph in Fig. 3 shows that the electric field is concentrated at the edge portion of the superconducting wire 10, resulting in high electric field strength. Since the copper plating layer 11 is formed thickly at the portion of the superconducting wire 10 where the electric field strength is high, a dogbone occurs in which the copper plating layer 11 covering the edge portion of the superconducting wire 10 becomes thick, as illustrated in Fig. 4.

[0028] Figures 5A, 5B, and 5C are scanning electron microscope (SEM) images showing the shape of copper plating layer 11 obtained by electroplating a single superconducting wire 10 as shown in the cross section of Figure 3. Figures 5A, 5B, and 5C are observation images of the vicinity of the left end, the center, and the right end, respectively, of a cross section in the width direction of superconducting wire 1. Figures 5A, 5B, and 5C show that dog bones actually occur when electroplating is performed on a single superconducting wire 10.

[0029] The upper cross-sectional view of Figure 6 is a vertical cross-sectional view in the width direction of three superconducting wires 10 arranged parallel to each other at intervals on the same plane 50, and the lower graph of Figure 6 is a graph showing the electric field distribution when electroplating is performed on the plane 50 on which the three superconducting wires 10 shown in the upper cross-sectional view are placed, calculated by finite element method modeling.

[0030] The position [mm] on the horizontal axis of the graph in Fig. 6 corresponds to the position on plane 50 in the width direction of superconducting wire 10 shown in the upper cross-sectional view. Here, width W of three superconducting wires 10 shown in the cross-sectional view in Fig. 6 is 4 mm, and spacing D is 1 mm.

[0031] 6 shows that the electric field concentration is alleviated and the electric field strength is suppressed at the edge portions on both sides of the central superconducting wire 10, which is flanked by other superconducting wires 10. Therefore, an increase in the thickness of the copper plating layer 11 is suppressed at the edge portions of the superconducting wire 10 where the electric field strength is suppressed.

[0032] Specifically, according to the graph of Fig. 6, the electric field strength at both edge portions of the central superconducting wire 10 flanked by other superconducting wires 10 is approximately 300 V / m. On the other hand, according to the graph of Fig. 3, the electric field strength at both edge portions of a single superconducting wire 10 flanked by no other superconducting wires 10 is approximately 1500 V / m. In other words, the presence of other superconducting wires 10 on both sides can reduce the electric field strength at the edge portions of the superconducting wire 10 to approximately one-fifth, thereby improving the uniformity of the thickness of the copper plating layer 11.

[0033] 7A, 7B, and 7C are SEM observation images showing the shape of copper plating layer 11 obtained by electroplating superconducting wire 10 in a state where other superconducting wires 10 are present on both sides, such as superconducting wire 10 located in the center as shown in the cross-sectional view of Fig. 6. Figures 7A, 7B, and 7C are observation images of the vicinity of the left end, the center, and the right end of a cross section of superconducting wire 10 in the width direction, respectively. Figures 7A, 7B, and 7C show that when electroplating is performed on superconducting wire 10 in a state where other superconducting wires 10 are present on both sides, dog-bone formation is actually suppressed, and the thickness of copper plating layer 11 is approximately equal near the center and near the ends of superconducting wire 10.

[0034] 8A is a schematic diagram showing a configuration example of a plating apparatus 2 for electroplating a superconducting wire 100. The plating apparatus 2 includes a treatment tank 21 containing a plating solution 20 containing copper ions, an electrode 22 disposed in the plating solution 20, a plurality of guide reel assemblies 23 for guiding the transportation of the superconducting wire 100, and an electrolyte tank 24 for preventing drying of the plated superconducting wire 100. The electrode 22 may be an electrode made of copper or a metal equipped with an electrocatalyst, such as a copper electrode or a dimensionally stable anode (DSA).

[0035] The plating solution 20 contains, for example, 230 to 280 g / L of copper sulfate (CuSO ４ ・5H ２ O), 60-100 g / L sulfuric acid (H ２ SO ４ ), and 60 to 130 mg / L of sodium chloride. Sodium chloride can increase the electrical conductivity of the plating solution 20 and affect the deposition process, thereby making the finish of the copper plating layer 11 brighter.

[0036] The guide reel assemblies 23 are installed so that their axial directions (the lengthwise direction of the shafts 233, which will be described later) are parallel to one another.

[0037] In the plating device 2, one superconducting wire 100 is spirally wound around a plurality of guide reel assemblies 23, and in the plating solution 20, a plurality of strip-shaped portions (the above-mentioned plurality of superconducting wires 10) that are part of the wound superconducting wire 100 are arranged parallel to each other with spaces between them on the same plane 50. Then, a voltage is applied between the superconducting wire 100 and the electrode 22, and a copper plating layer 11 is formed on the surface of the plurality of superconducting wires 10 with the plurality of superconducting wires 10 having the same potential and voltage.

[0038] The plating apparatus 2 typically includes at least two sets (for example, two sets, or alternatively, four sets), each set consisting of two guide reel assemblies 23 installed closely to each other, one inside and one outside the plating solution 20. These multiple sets of guide reel assemblies 23 are positioned parallel to each other at a distance according to the size of the plating apparatus 2.

[0039] In the example shown in Fig. 8A, the plating apparatus 2 is equipped with four guide reel assemblies 23. Here, the guide reel assembly 23 at the top left in Fig. 8A is referred to as guide reel assembly 23a, the guide reel assembly 23 at the bottom left as guide reel assembly 23b, the guide reel assembly 23 at the top right as guide reel assembly 23c, and the guide reel assembly 23 at the bottom right as guide reel assembly 23d.

[0040] Furthermore, a set of guide reel assemblies 23a and 23b installed at different heights on the inlet side (left side in FIG. 8A ) of superconducting wire 100 will be referred to as a first set, and a set of guide reel assemblies 23c and 23d installed at different heights on the outlet side (right side in FIG. 8A ) of superconducting wire 100 will be referred to as a second set. When four sets of guide reel assemblies 23 are used, two structures in which superconducting wire 100 is wound around the first set and the second set are arranged side by side.

[0041] Guide reel assembly 23a and guide reel assembly 23c, which are installed outside plating solution 20, are contact reels that supply current to superconducting wire 100. Since wound superconducting wire 100 contacts guide reel assembly 23a and guide reel assembly 23c at each turn, an equal potential is supplied to each turn. Therefore, a plurality of superconducting wires 10 can be arranged parallel to each other at intervals on the same plane 50 as calculated.

[0042] Guide reel assembly 23b and guide reel assembly 23d installed in plating solution 20 are guide reels for adjusting the position of superconducting wire 100 in plating solution 20. Note that if plating apparatus 2 has only two guide reel assemblies 23, one must be a contact reel installed outside plating solution 20, and the other must be a guide reel installed in plating solution 20.

[0043] When plating the superconducting wire 100, the electrode 22 is used as an anode and the superconducting wire 100 is used as a cathode, and a voltage is applied between them. In the plating solution 20 containing copper ions, copper is precipitated on the surface of the superconducting wire 100 (i.e., the plurality of superconducting wires 10) to form a copper plating layer 11. When DSA is used as the electrode 22, specifically, Ti is replaced with RuO２ or IrO ２ Coated with (RuO ２ and IrO ２ In this case, Cu is supplied to the plating solution 20 by circulation of the electrolyte through a soluble source of Cu.

[0044] 8B is a perspective view of guide reel assembly 23. Guide reel assembly 23 includes a plurality of stacked, disk-shaped guide reels 230 and a single shaft 233 that passes through holes provided in the centers of the guide reels 230 and holds the guide reels 230. Spacers are disposed between adjacent guide reels 230. The thickness of the spacer is, for example, about 0.3 mm, but can be set appropriately depending on the size of the spacing D between the plurality of superconducting wires 10 during electroplating.

[0045] 8B , guide reel assembly 23 includes 22 guide reels 230. Each guide reel 230 includes a body 231 that contacts the main surface of superconducting wire 100, and flanges 232 provided on both sides of body 231.

[0046] Superconducting wire 100 sent to plating device 2 is spirally wound around guide reel assemblies 23a to 23d a number of times corresponding to the number of guide reels 230 included in each of guide reel assemblies 23a to 23d.

[0047] In plating device 2, electroplating is performed while superconducting wire 100 is being fed. Superconducting wire 100 is fed while circling around 23a to 23d, and is plated while passing through plating solution 20.

[0048] Superconducting wire 100 sent from the first set, which is a set of guide reel assemblies 23a and 23b, toward the second set, which is a set of guide reel assemblies 23c and 23d, changes direction and returns from the second set to the first set.

[0049] Guide reel assembly 23b, which is the lower guide reel assembly 23 of the first set, and guide reel assembly 23d, which is the lower guide reel assembly 23 of the second set, are placed in plating solution 20, and superconducting wire 100 is subjected to plating treatment mainly during the process of returning from the second set to the first set.

[0050] The electrolyte tank 24 installed between the guide reel assembly 23a and the guide reel assembly 23c is a tank containing an electrolyte similar to the plating solution 20, and the superconducting wire 100 passes through the electrolyte tank 24, thereby preventing the superconducting wire 100 from drying out after coming out of the plating solution 20 until it enters the plating solution 20 again. If the superconducting wire 100 comes out of the plating solution 20 and dries out, the electrolyte will precipitate, which will interfere with the plating process in the next turn. Note that instead of the electrolyte tank 24, a shower may be used to spray the electrolyte onto the superconducting wire 100.

[0051] In each of guide reel assemblies 23a to 23d, superconducting wire 100 passes through a plurality of guide reels 230 (usually all guide reels 230) in order starting from guide reel 230 located at one end. That is, in the nth winding, superconducting wire 100 passes through the nth guide reel 230 from one end of guide reel assemblies 23a to 23d (n is a natural number having a maximum value equal to the number of guide reels 230 included in each of guide reel assemblies 23a to 23d).

[0052] The diameters of the barrels 231 of the multiple guide reels 230 included in each of guide reel assemblies 23a to 23d are the same. Furthermore, in each of guide reel assemblies 23a to 23d, the multiple guide reels 230 are arranged parallel to one another. Furthermore, in each of guide reel assemblies 23a to 23d, a predetermined distance is provided between the barrels 231 of adjacent guide reels 230 by means of flanges 232 of the guide reels 230 and spacers between adjacent guide reels 230. This distance between the barrels 231 of adjacent guide reels 230 corresponds to the distance D between the multiple superconducting wires 10 described above.

[0053] 2, between guide reel assemblies 23, for example, between guide reel assembly 23b and guide reel assembly 23d, a plurality of superconducting wires 10 are arranged parallel to one another at intervals on the same plane 50. Therefore, in plating apparatus 2, electroplating is performed on a plurality of superconducting wires 10 arranged parallel to one another at intervals on the same plane.

[0054] Furthermore, since there are other superconducting wires 10 on both sides of the superconducting wires 10 other than the two at both ends (the superconducting wires 10 included in the first and last turns of the superconducting wire 100), the number of times the superconducting wire 100 is wound around the guide reel assemblies 23a to 23d increases, and the greater the number of superconducting wires 10, the more effectively dog ​​bones are suppressed and the more uniform the thickness of the copper plating layer 11 formed.

[0055] For example, the number of superconducting wires 10 arranged parallel to one another at intervals on the same plane 50 during the plating process is preferably three or more, and therefore, it is preferable that the guide reel assemblies 23a to 23d can wind the superconducting wire 100 three or more times, i.e., the superconducting wire 100 can pass through the plating solution 20 three or more times. Furthermore, if the guide reel assemblies 23a to 23d wind the superconducting wire 100 too many times, it becomes difficult to control the tension of the superconducting wire 100, so it is preferable that the number of times is 30 or less. That is, the number of superconducting wires 10 arranged parallel to one another at intervals on the same plane 50 during the plating process is preferably 30 or less.

[0056] Effect of the Embodiments According to the above-described embodiments of the present invention, a plating layer can be formed on the surface of a superconducting wire by electroplating while suppressing dog bones, using a novel method not previously known.

[0057] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit of the invention. Furthermore, the components of the above-described embodiments can be combined in any manner without departing from the spirit of the invention.

[0058] Furthermore, the above-described embodiments do not limit the scope of the invention as claimed, and it should be noted that not all of the combinations of features described in the embodiments are necessarily essential to the means for solving the problems of the invention.

[0059] To provide a plating method for a superconducting wire by electroplating, which is different from conventional methods and can form a plating layer on the surface of the superconducting wire while suppressing dog bones.

[0060] REFERENCE SIGNS LIST 1, 10, 100 Superconducting wire 11 Copper plating layer 50 Plane 2 Plating device 20 Plating solution 23, 23a to 23d Guide reel assembly 230 Guide reel

Claims

1. A method for plating a superconducting wire, which comprises electroplating the surface of a tape-shaped superconducting wire containing a superconductor layer to form a copper plating layer, wherein the electroplating is performed on a plurality of the superconducting wires arranged in parallel with a gap between them on the same plane.

2. The method for plating a superconducting wire according to claim 1, wherein the interval is 0.3 mm or more and equal to or less than the width of the superconducting wire.

3. The method for plating a superconducting wire according to claim 1 or 2, wherein the plurality of superconducting wires are parts of a single superconducting wire wound in a spiral shape.

4. The method for plating a superconducting wire according to claim 3, wherein the number of the plurality of superconducting wires is three or more.

5. A plating apparatus used for electroplating a superconducting wire, comprising: a treatment tank containing a plating solution; an electrode placed in the plating solution; and a plurality of guide reel assemblies, each having a plurality of stacked guide reels that guide the transport of the superconducting wire; wherein the superconducting wire is wound around the plurality of guide reel assemblies, and in the plating solution, a voltage is applied between the superconducting wire and the electrode in a state where a plurality of strip-shaped portions that are part of the wound superconducting wire are arranged parallel to each other with spaces between them on the same plane, thereby forming a copper plating layer on the surface of the superconducting wire.

6. The plating apparatus according to claim 5, wherein the gap is 0.3 mm or more and equal to or less than the width of the superconducting wire.

7. The plating apparatus according to claim 5 or 6, wherein the plurality of guide reel assemblies are capable of winding the superconducting wire three or more times.

8. A plating apparatus as set forth in claim 5 or 6, wherein the plurality of guide reel assemblies include a contact reel installed outside the plating solution for supplying current to the superconducting wire, and the wound superconducting wire comes into contact with the contact reel at each turn, so that an equal potential is supplied to each turn portion.

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