JP2015222700A - Superconductive tape wire and superconductive coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive tape wire and a superconductive coil which are strong to load stress generated in individual layers of a superconductive wire and reduce eddy currents occurring during AC electrification while minimizing decrease of the current density.SOLUTION: A superconductive tape wire 10 includes a superconductive part 14 which is composed of a thin-film superconductive wire 1 with its outer periphery coated with a good-conductivity metal and a reinforcing part which is fastened to the outer surface, on the side of the superconductive layer 4, of the thin-film superconductive wire 1 constituting the superconductive part 14 and composed of a reinforcing tape wire 11. In the superconductive part 14, there is provided a partition part 13 which divides the superconductive part 14 into a plurality of sections in the width direction of the thin-film superconductive wire 1 to fragment superconductive connections among the individual sections of the superconductive part 14.

Description

  The present invention relates to a superconducting tape wire and a superconducting coil.

  A conventional multilayer superconducting tape wire has a structure in which an intermediate layer is formed on a substrate, an oxide superconducting layer is formed on the intermediate layer, and a protective layer is formed on the oxide superconducting layer. It is common. When a superconducting coil is prepared using this conventional multilayer superconducting tape wire and AC operation is performed, an eddy current is generated in the superconducting coil, resulting in an AC loss.

  As a technique for reducing such AC loss, there has been proposed a superconducting tape wire in which a thinning groove that divides an oxide superconducting layer into a plurality in the width direction is formed so as to reach the base material (for example, Patent Documents). 1).

Japanese Patent No. 4777749

  However, in the superconducting tape wire described in Patent Document 1, each layer above the substrate is divided by a groove, so that this groove forms a hollow portion inside the superconducting tape wire, and the superconducting tape wire. There is a concern in terms of strength compared to a superconducting tape wire having a multilayer structure in which no hollow portion is formed.

  In addition, even when a superconducting coil is created using a multi-layer superconducting tape wire in which no hollow portion is formed inside the superconducting tape wire and operated, the load stress generated in each layer constituting the superconducting tape wire Since the layer can be peeled, deformed, and cracked, it can be said that it is desirable to avoid a slight decrease in strength of the superconducting tape wire.

  The present invention has been made in consideration of the above-mentioned problems. For a superconducting coil formed by winding a superconducting tape wire, the present invention is strong against load stress generated in each layer of the superconducting wire, and is an eddy current generated during AC energization. It is an object of the present invention to provide a superconducting tape wire and a superconducting coil capable of suppressing the above-described conventional problems.

  In order to solve the above-described problem, a superconducting tape wire according to an embodiment of the present invention has a superconducting portion formed of a superconducting wire whose outer periphery is covered with a highly conductive metal layer, and the superconducting portion forming the superconducting portion. A reinforcing portion formed of a reinforcing tape wire fixed to the outer surface of the wire on the superconducting layer side, and the superconducting portion is divided into a plurality of the superconducting portions in the width direction of the superconducting wire, The present invention is characterized in that an isolating portion for separating superconducting connection between each section of the superconducting portion is provided.

  A superconducting coil according to an embodiment of the present invention is formed by winding the superconducting tape wire around a winding frame.

  ADVANTAGE OF THE INVENTION According to this invention, it is strong with respect to the load stress which arises in each layer of a superconducting wire about the superconducting coil produced by winding a superconducting tape wire, and can suppress the eddy current which generate | occur | produces at the time of alternating current conduction more than before.

The block diagram which shows an example of the thin film superconducting wire (conventional superconducting tape wire) applied to the superconducting tape wire which concerns on embodiment of this invention. The cross-sectional view of the superconducting tape wire which concerns on embodiment of this invention. It is a block diagram which shows the structure of the superconducting coil which concerns on embodiment of this invention, (A) is a top view, (B) is a longitudinal cross-sectional view, (C) is an expanded sectional view of a coil | winding part. Explanatory drawing (table) which shows the item list and evaluation result of the Example of a superconducting coil which concerns on embodiment of this invention, and a comparative example. Explanatory drawing which shows the relationship of n value and the current density with respect to the reinforcement tape wire thickness about the Example and comparative example of the superconducting coil which concern on embodiment of this invention.

  Hereinafter, a superconducting tape wire according to an embodiment of the present invention and a superconducting coil using the superconducting tape wire will be described with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a transverse section of a thin film superconducting wire (conventional superconducting tape wire) 1 applied to a superconducting tape wire 10 which is an example of a superconducting tape wire according to an embodiment of the present invention. 1 is a cross-sectional view of a superconducting tape wire 10. FIG. In FIG. 1, the thickness direction of the thin film superconducting wire 1 is the vertical direction, and in FIG. 2, the thickness direction of the thin film superconducting wire 1 is the left and right direction.

  As shown in FIG. 2, the superconducting tape wire 10 is composed of a multi-layered wire having a predetermined thickness and a predetermined width, such as a thickness of 0.13 mm and a width of 5.0 mm, and the outer periphery is a highly conductive metal. The thin film superconducting wire 1 and the reinforcing tape wire 11 are brazed with a brazing material 12 such as solder so that the superconducting layer 4 side of the thin film superconducting wire 1 covered with (stabilizing layer 6) and the reinforcing tape wire 11 face each other. By being fixed, it is configured.

  That is, the superconducting tape wire 10 is formed of a thin film superconducting wire 1 corresponding to a general (conventional) superconducting tape wire, and is formed of a superconducting portion 14 having superconducting properties and a reinforcing tape wire 11, and the superconducting portion 14 is formed. It is the structure provided with the reinforcement part to reinforce. The reinforcing portion of the superconducting tape wire 10 is fixed to the outer surface of the thin film superconducting wire 1 on the superconducting layer 4 side so as to be energized with solder or the like.

  In addition, the superconducting tape wire 10 divides the superconducting portion 14 into a plurality of, for example, three in the width direction of the thin film superconducting wire 1 (the length in the horizontal direction in FIG. 1 and the length in the vertical direction in FIG. 2). In addition to (separation), a separating portion 13 is provided that divides the superconducting connection between the sections of the superconducting portion 14.

  A superconducting tape wire 10 illustrated in FIG. 2 has three thin film superconducting wires 1 having a thickness of 0.13 mm and a width of 1.6 mm arranged in parallel in the same direction in the width direction (vertical direction in FIG. 2). Each separation portion 13 between the wires 1 has a 0.1 mm gap, and a reinforcing tape wire 11 having a thickness of 0.01 to 0.08 mm (see FIG. 4 described later) and a width of 5.0 mm is brazed with a brazing material 12. Thus, the superconducting tape wire 10 having a thickness of 0.14 to 0.21 mm and a width of 5.0 mm formed by fixing the thin film superconducting wire 1 and the reinforcing tape wire 11 to each other.

  The thickness of the brazing material 12 is usually about several to several tens of microns [μm], which is about an order of magnitude smaller than the thickness of the thin film superconducting wire 1 and the reinforcing tape wire 11 and can be ignored. In the present description, the thickness of the brazing filler metal 12 is not taken into account (ignored) because it is not thick.

  As shown in FIG. 1, the thin film superconducting wire 1 has, for example, an intermediate layer 3 formed on a tape substrate 2, a superconducting layer 4 formed on the intermediate layer 3, and a superconducting layer 4 on the superconducting layer 4. The protective layer 5 is formed, and the surface of the laminate of the tape substrate 2, the intermediate layer 3, the superconducting layer 4, and the protective layer 5 is covered with the stabilization layer 6.

  The tape substrate 2 is formed of a material such as a nickel alloy such as stainless steel or Hastelloy (registered trademark), a silver alloy, or the like.

  The intermediate layer 3 is a diffusion prevention layer and is made of a material such as cerium oxide, YSZ, magnesium oxide, yttrium oxide, ytterbium oxide, barium zirconia, and is formed on the tape substrate 2.

The superconducting layer 4 is made of, for example, a superconducting thin film having a RE123-based composition (RE ₁ B ₂ C ₃ O ₇ or the like). Note that “RE” in “RE ₁ B ₂ C ₃ O ₇ ” is at least one of rare earth elements (for example, neodymium (Nd), gadolinium (Gd), holmium (Ho), samarium (Sm), etc.) and yttrium elements. “B” means barium (Ba), “C” means copper (Cu), and “O” means oxygen (O).

  The protective layer 5 is provided for the purpose of preventing the superconducting layer 4 from deteriorating due to contact with moisture in the air, and is made of silver or the like. The protective layer 5 also serves to prevent the superconducting layer 4 from burning when electricity flows excessively through the superconducting layer 4.

  The stabilization layer 6 is provided for the purpose of preventing the superconducting layer 4 from burning when excessive electricity flows through the superconducting layer 4, for example, plating with a metal having good conductivity such as copper or silver. Formed by.

  The reinforcing tape wire 11 has a function as a base material for fixing the thin film superconducting wire 1 in which a plurality of wires are arranged in parallel at the end. Further, the reinforcing tape wire 11 is a layer of a superconducting wire (corresponding to the thin film superconducting wire 1, the same applies hereinafter) by bending stress, cooling, or electromagnetic force of the superconducting coil 50 (FIG. 3) formed by winding. It has a function to reinforce the superconducting wire against the load stress generated in.

  The reinforcing tape wire 11 is selected from, for example, a material made of at least one of stainless steel, copper-beryllium (Cu—Be) alloy, aluminum, copper, nickel, and copper-nickel (Cu—Ni) alloy.

  The brazing material 12 has a function of physically adhering the thin film superconducting wire 1 (more specifically, the stabilization layer 6) and the reinforcing tape wire 11 while electrically connecting them. The brazing material 12 fixes the thin film superconducting wire 1 and the reinforcing tape wire 11 so as to be conductive. The brazing material 12 is preferably a brazing material that has good conductivity and can be joined at a relatively low temperature, such as solder.

  The isolation part 13 has a function of cutting off the superconducting connection in the width direction of the thin film superconducting wire 1. The isolation portion 13 is, for example, a gap or an interface between different thin film superconducting wires 1 (they may be in contact with each other as long as they are separated).

  The superconducting tape wire 10 includes a superconducting portion 14 formed of the thin film superconducting wire 1 and a reinforcing tape wire 11 fixed to the stabilization layer 6 (outer surface) on the superconducting layer 4 side of the thin film superconducting wire 1 with a brazing material 12. The isolation part 13 which cuts off the superconducting connection of the width direction in the superconducting part 14 is provided. The reason why such a configuration is adopted is from the viewpoint of solving three problems of strength, eddy current, and workability of the superconducting portion 14 (thin film superconducting wire 1).

  More specifically, the wider the width of the thin film superconducting wire 1 is, the better the workability is, but the eddy current is likely to occur. On the other hand, when the width of the thin film superconducting wire 1 is narrow, eddy currents are hardly generated, but workability is impaired. Therefore, in the superconducting tape wire 10, the narrow thin film superconducting wire 1 is arranged in parallel in the same direction in the width direction of the thin film superconducting wire 1, and the end portions of the reinforcing tape wire 11 wider than the thin film superconducting wire 1. In such a structure, a superconducting connection of the superconducting portion 14 is maintained without providing a hollow portion such as a groove or a gap in the thin film superconducting wire 1 (width of one thin film superconducting wire 1). And the superconducting tape wire 10 as a whole maintains the conventional width.

  In this way, the thin film superconducting wire 1 having a narrow width is arranged in parallel in the same direction in the width direction of the thin film superconducting wire 1, and these end portions are fixed to the reinforcing tape wire 11 wider than the thin film superconducting wire 1. Thus, the superconducting portion 14 itself is not changed without reducing the strength of the thin film superconducting wire 1 without changing the width of the superconducting portion 14 itself (the sum of the width of each thin film superconducting wire 1 and the width of each separating portion 13). By reducing the width at which the superconducting connection is maintained, the effect of suppressing the generation of eddy currents is enhanced without reducing the strength of the superconducting portion 14 (thin film superconducting wire 1) and without impairing workability. ing.

  Further, by giving the necessary thickness to the reinforcing tape wire 11, not only as a base material for fixing the thin film superconducting wire 1 at one end in the thickness direction but also due to load stress generated in each layer of the thin film superconducting wire 1. It can function as a reinforcing member that enhances the effect of preventing the occurrence of peeling, deformation, cracks, and the like. That is, by providing the reinforcing tape wire 11 with a necessary thickness, the superconducting coil 50 (FIG. 3) can be made stronger against coil deterioration.

  Furthermore, as will be described later, by setting the thickness of the reinforcing tape wire 11 appropriately (over 0.020 mm and 0.068 mm or less, more preferably 0.350 mm or more and 0.065 mm or less), the decrease in current density is also minimized. It can be stopped to the limit. That is, it is possible to achieve both minimization of current density reduction and prevention of deterioration of the superconducting coil 50.

  Then, the superconducting coil which concerns on embodiment of this invention, and its evaluation result (current density and n value) are demonstrated.

  FIG. 3 is a configuration diagram showing a configuration of a superconducting coil 50 which is an example of a superconducting coil according to an embodiment of the present invention, where (A) is a plan view, (B) is a longitudinal sectional view, and (C) is a winding. It is an expanded sectional view of a part.

  A superconducting coil 50 which is an example of a superconducting coil according to an embodiment of the present invention is obtained by, for example, attaching a multilayer superconducting tape wire 10 as described above to a winding frame 51 and further winding an insulating tape wire 15 in an overlapping manner. The winding portion 52 is formed, and the whole is an impregnated coil impregnated with a resin such as an epoxy resin.

  Here, in the superconducting coil 50 illustrated as an example in FIG. 3, the inner diameter of the winding frame 51 is 30 mm, the width of the insulating tape wire 15 is 5.0 mm, and the thickness is 0.08 mm. The superconducting tape wire 10 has a width of 5.0 mm and a thickness of 0.14 to 0.21 mm.

  In the superconducting coil 50 configured in this manner, the superconducting portion 14 of the superconducting tape wire 10 is provided with the separating portion 13 that cuts off the superconducting connection, so that the width direction of the winding portion 52 (the top and bottom shown in FIG. (Direction), the superconducting connection can be cut off, and the length of the winding portion 52 in the width direction is shorter than that in the prior art, so that generation of eddy currents during AC energization can be suppressed more than in the past.

  Moreover, according to the superconducting coil 50, since the superconducting tape wire 10 has a reinforcing portion, each layer of the thin film superconducting wire 1 is formed in the superconducting coil 50 formed by winding the superconducting tape wire 10 during the production or operation of the superconducting coil 50. It is possible to adopt a configuration that is resistant to coil deterioration caused by the load stress generated in.

  Further, according to the superconducting coil 50, as will be described later, the thickness of the reinforcing tape wire 11 as the reinforcing portion is appropriately (over 0.020 mm and 0.068 mm or less, more preferably 0.350 mm or more and 0.065 mm or less). By setting, the decrease in current density is kept to a minimum, and the occurrence of peeling, deformation, cracks, etc. due to the load stress generated in each layer of the thin film superconducting wire 1 is prevented, and the superconducting coil 50 is deteriorated. Can be prevented.

[Example]
Then, the Example and comparative example of the superconducting coil which concern on embodiment of this invention are demonstrated. Examples and Comparative Examples to be described later confirm the effectiveness and effective range of the reinforcing portion of the superconducting tape wire 10 that is wound when the superconducting coil 50 that is an example of the superconducting coil according to the embodiment of the present invention is created. Is for.

  FIG. 4 is an explanatory diagram (table) showing a list of specifications and evaluation results (current density and n value) of examples and comparative examples of the superconducting coil 50 as the superconducting coil according to the embodiment of the present invention.

  Here, the created superconducting coils (coil numbers # 1 to # 21) have copper tape wires (reinforcing portions) as reinforcing tape wires fixed to the outer surface (stabilizing layer 6) on the superconducting layer side of the thin film superconducting wires. This is an impregnated coil formed by attaching a superconducting tape wire to the winding frame 51 (FIG. 3) and further winding the insulating tape wire 15 (FIG. 3). The width of each superconducting tape wire is 5. 0 mm.

  Among the coil numbers # 1 to # 21, the superconducting coils of the coil numbers # 1 to # 14 are formed by extending the thin film superconducting wire 1 having a thickness of 0.13 mm and a width of 1.6 mm in the same direction in the width direction (in FIG. ), And the width of the superconducting part 14 is set to 5.0 mm with each separating part 13 between the thin film superconducting wires 1 having a gap of 0.1 mm, and the thickness of the copper tape wire having a width of 5.0 mm. By attaching the superconducting tape wire 10 (FIG. 2) whose thickness is changed in 8 ways in the range of 0 mm (no) to 0.080 mm (present) to the winding frame 51, and further winding the insulating tape wire 15 in an overlapping manner. It is an impregnated coil to be formed.

  In addition, coil numbers # 15 to # 21 have a 5.0 mm width copper tape wire (reinforcing portion) and a 5.0 mm width corresponding to a general (conventional) superconducting tape wire not provided with the separation portion 13. A superconducting tape wire is prepared which is fixed to the thin film superconducting wire 1 and the thickness of the copper tape wire is changed in seven ways within a range of 0.010 mm to 0.080 mm. This is the same as the coil numbers # 1 to # 14. It is an impregnation coil formed by attaching to the winding frame 51 and further winding the insulating tape wire 15 in an overlapping manner.

  In this description, among coil numbers # 1 to # 21, # 6 to # 13 and # 16 to # 19 are examples, and the others (# 1 to # 5, # 14, # 15, # 20, # 21) are It is a comparative example. In addition, as an index for evaluating the superconducting coils according to Examples and Comparative Examples, current density (relative value) is used for performance, and n value is used for deterioration of the superconducting coil.

  As for the current density, the case where there is no reinforcing portion, that is, the case where the thickness of the copper tape wire is 0 mm is defined as 100%, and the current density (relative value) with respect to the case where there is no reinforcing portion is obtained. If it is 95.0% or more, which is a range of 5% reduction or less, it is judged that the performance is good.

  As the n value, a voltage characteristic with respect to a current when energized in liquid nitrogen is obtained, and a value derived from the obtained result is used. If the n value is 20.00 or more, it is generally determined that the superconducting coil is in a good state without deterioration. If the n value is 20.00, the superconducting coil is in a good state without deterioration. Judge.

  According to FIG. 4, in coil number # 1, which represents the case where there is no copper tape wire (reinforcing tape wire 11: FIG. 2), the n value is 5.30, which is less than 20.00, and the superconducting coil deteriorates. Can be judged.

  Subsequently, in the case where there is a copper tape wire (reinforcement tape wire 11: FIG. 2) and the thickness is 0.010 mm, the coil numbers # 2 and 3 each represent a current density of 95% or more. However, since the n values are 9.25 and 3.25, respectively, both being less than 20.00, it can be determined that the superconducting coil is deteriorated.

  Moreover, in coil numbers # 4 and 5 representing the case where the thickness of the copper tape wire is 0.020 mm, the current density is 95% or more, but the n values are 26.90 and 14.00, respectively. is there. Therefore, with respect to the coil # 4, the deterioration of the coil due to the load stress generated in each layer of the superconducting wire is suppressed while minimizing the decrease in the current density (while ensuring a current density of 95% or more). Although the result that the n value of 20 or more could be obtained was obtained, the decrease in current density was suppressed to the minimum for the other coil number # 5, but it occurred in each layer of the superconducting wire. The result that the coil deterioration resulting from load stress was not suppressed was obtained.

  Furthermore, in the coil numbers # 6 and 7 representing the case where the thickness of the copper tape wire is 0.035 mm which exceeds 0.020 mm, the current density is 95% or more, and the n value is 30. The result of 20.00 or more of 90, 30.80 could be obtained. Therefore, as for coil numbers # 6 and 7, it was obtained that the deterioration of the coil due to the load stress generated in each layer of the superconducting wire was suppressed while minimizing the decrease in current density.

  From the results of these coil numbers # 1 to # 7, even if the reinforcing tape wire (copper tape wire) 11 is fixed to the thin film superconducting wire 1, the thickness of the reinforcing tape wire 11 is sufficiently small, such as less than 0.020 mm. If not, it has been found that it is not possible to sufficiently obtain the effect of suppressing coil deterioration caused by load stress generated in each layer of the superconducting wire.

  Moreover, although it was divided into good or bad when the thickness of the copper tape wire is 0.020 mm, since it is good at any more than that, the thickness of the reinforcing tape wire 11 near 0.020 mm is the load. It is estimated that this is the boundary of whether or not the effect of suppressing the coil deterioration caused by the stress can be obtained. Therefore, in order to suppress coil deterioration caused by load stress generated in each layer of the superconducting wire, the thickness of the reinforcing tape wire 11 is preferably more than 0.020 mm, and more preferably 0.035 mm or more. It was discovered.

  Subsequently, when the thickness of the copper tape wire exceeds 0.020 mm and increases to 0.035 mm, 0.050 mm, 0.065 mm, 0.070 mm, 0.080 mm, the n value is 20.00 or more. Are satisfied, but the current density gradually decreases and eventually falls below 95%.

  Specifically, in the coil numbers # 8 to 11, the n values are 28.70, 26.60, 29.40, and 27.80, respectively, which are 20.00 or more. Are 96.3, 96.3, 95.2 and 95.2, respectively, which are 95% or more. Therefore, when the thickness of the copper tape wire is in the range of 0.035 to 0.065 mm, it is possible to minimize the decrease in current density (to ensure a current density of 95% or more) and to use a superconducting wire (thin film superconducting wire). As a result, the coil deterioration caused by the load stress generated in each layer of 1) can be suppressed.

  On the other hand, in the coil numbers # 12 to 14 in which the thickness of the copper tape wire is 0.070 mm or more, the n values are 29.30, 29.20, and 24.70, respectively, and 20.00 or more, respectively. However, the current densities are 94.9, 94.9, and 94.2%, respectively, which are less than 95%. Therefore, in the range where the thickness of the copper tape wire is 0.070 mm or more (0.080 mm or less), coil deterioration caused by load stress generated in each layer of the superconducting wire (thin film superconducting wire 1) is suppressed (n value). On the other hand, the current density is greatly reduced, and the decrease in current density cannot be minimized (a current density of 95% or more cannot be secured).

  From the results of these coil numbers # 8 to # 14, when the thickness of the reinforcing tape wire (copper tape wire) 11 has a sufficient thickness exceeding 0.020 mm, from the viewpoint of suppressing coil deterioration caused by load stress. Is effective, but when the thickness is increased too much, it is not preferable from the viewpoint of maintaining the current density. Specifically, it has been found that when the thickness is 0.070 mm or more, a current density of 95% or more cannot be ensured, and a decrease in current density cannot be minimized.

  Since the current density depends on the coil shape of the superconducting coil, the thickness (theoretical value) of the copper tape wire at which the current density is 95% can be calculated. The thickness (theoretical value) of the copper tape wire with a current density of 95% calculated from the shape of the superconducting coil that was prototyped this time is about 0.068 mm, and the results of the above examples and comparative examples are the theoretical values. The result is supported.

  Therefore, in order to minimize the decrease in current density (to ensure a current density of 95% or more), the thickness of the reinforcing tape wire 11 is preferably 0.068 mm or less, and 0.065 mm or less. Has been found to be more preferable.

  On the other hand, in addition to the superconducting coil 50 formed by winding the superconducting tape wire 10 provided with the separation portion 13, a superconductivity in which a reinforcing portion is added to a general (conventional) superconducting tape wire not provided with the separation portion 13. The superconducting coils of coil numbers # 15 to # 21, which are superconducting coils formed by winding a tape wire, are similar to the results of the superconducting coil 50 formed by winding the superconducting tape wire 10 provided with the separation portion 13. It was confirmed that the results were obtained.

  Specifically, in the superconducting coil of coil number # 15 in which the thickness of the reinforcing tape wire (copper tape wire) 11 is 0.010 mm, the current density can be secured at 99.2%, which is 95% or more. However, since the n value is 6.25 and less than 20.00, it can be determined that the superconducting coil is deteriorated.

  In the superconducting coils of coil numbers # 16 to # 19 in which the thickness of the reinforcing tape wire (copper tape wire) 11 is 0.020 mm to 0.065 mm, the n values are 24.60, 30.80, 27.50 and 29.00, both of which are 20.00 or more, and the current densities are 98.5, 97.4, 96.3, 95.2, both of which are 95% or more. Yes. Therefore, when the thickness of the reinforcing tape wire (copper tape wire) 11 is in the range of 0.020 mm to 0.065 mm, the coil caused by the load stress generated in each layer of the superconducting wire while minimizing the decrease in current density. The result that the deterioration was also suppressed was obtained.

  Furthermore, in the superconducting coils of coil numbers # 20 and # 21 in which the thickness of the reinforcing tape wire (copper tape wire) 11 is 0.070 mm and 0.080 mm, the n values are 28.20 and 25.10, respectively. Although both are 20.00 or more, the current densities are 94.9 and 94.2%, respectively, and both are less than 95%. Therefore, in the range where the thickness of the copper tape wire is 0.070 mm or more (0.080 mm or less), coil deterioration caused by load stress generated in each layer of the superconducting wire (thin film superconducting wire 1) is suppressed (n value). On the other hand, the current density is greatly reduced, and the decrease in current density cannot be minimized (a current density of 95% or more cannot be secured).

  Summarizing the above results, the superconducting coil 50 (FIG. 3) formed by winding the superconducting tape wire 10 (FIGS. 2 and 3) is thinner than the conventional one while minimizing the decrease in current density. 1 (FIGS. 1 and 2), in order to prevent deterioration of the superconducting coil 50 due to the load stress generated in each layer, the thickness of the reinforcing tape wire (copper tape wire) 11 should be more than 0.020 mm and not more than 0.068 mm. Preferably, it is 0.035 mm or more and 0.065 mm or less.

  Further, a reinforced tape wire that is more useful in preventing deterioration of the superconducting coil 50 (FIG. 3) due to load stress generated in each layer of the thin film superconducting wire 1 (FIG. 2) than in the past while minimizing the decrease in current density. 11 (FIG. 2), the thickness of the superconducting tape wire 10 is substantially different (even if there is a difference in the effect on the eddy current) depending on whether or not the separator 13 is provided in the superconducting tape wire 10 (the presence or absence of the separator 13). There was no difference, and it was found that the thickness of the reinforcing tape wire (copper tape wire) 11 is preferably more than 0.020 mm and 0.068 mm or less, more preferably 0.035 mm or more and 0.065 mm or less.

  FIG. 5 is an explanatory diagram summarizing the evaluation results shown in FIG. 4, and more specifically, examples of superconducting coils according to the embodiment of the present invention and comparative examples (superconducting tape wires without reinforcing portions ( N value and current density with respect to reinforcing tape wire thickness for coil number # 1 created by winding thin film superconducting wire 1) and coil numbers # 2- # 14 created by winding superconducting tape wire 10) It is explanatory drawing which shows these relationships.

  In FIG. 5, the horizontal axis is the reinforcing tape wire thickness [mm], the left vertical axis is the n value, and the right vertical axis is the current density (the thickness of the reinforcing tape wire is 0 mm (no reinforcing tape wire) as a reference). 100%) relative value) [%].

  In addition, the region R1, the region R2, and the region R3 are respectively a range that achieves a current density of 95% theoretically derived from the shape of the superconducting coil, a range that achieves an n value of 20 or more, and a current. This is a range (product set of the regions R1 and R2) in which the density is 95% and the n value is 20 or more. Further, symbols L1 and P are a function indicating the relationship of the current density with respect to the reinforcing tape wire thickness and a point indicating the n value with respect to the reinforcing tape wire thickness (black diamond in FIG. 5).

  In FIG. 5, it is possible to suppress a decrease in current density to a minimum (a current density of 95% or more is ensured) (region R1) and a coil caused by load stress generated in each layer of the superconducting wire (thin film superconducting wire 1). The range in which deterioration can be suppressed (region R2) is the range of region R3. That is, the thickness of the reinforcing tape wire (copper tape wire) 11 may be more than 0.020 mm and 0.068 mm or less. Moreover, if the Example and comparative example mentioned above are considered, as for the thickness of the reinforcement tape wire (copper tape wire) 11, 0.035 mm or more and 0.065 mm or less are more preferable.

  As described above, according to the superconducting tape wire 10 and the superconducting coil 50 using the superconducting tape wire 10, the load stress generated in the superconducting portion 14 (each layer of each thin film superconducting wire 1) is suppressed while minimizing the decrease in current density. The resulting coil deterioration and eddy currents generated during AC energization can be reduced as compared with the conventional case.

  Further, in order to obtain an effect of suppressing eddy current by using a plurality of narrower thin film superconducting wires 1 without providing a gap for dividing the superconducting layer inside the thin film superconducting wire 1, The strength is not impaired.

  Further, if the length in the width direction showing the superconducting characteristics is increased in the winding portion of the superconducting coil, an eddy current is likely to be generated when alternating current is applied, but the superconducting coil 50 formed by winding the superconducting tape wire 10 (FIG. In the winding part 52 of 3), a plurality of narrower thin film superconducting wires 1 (FIG. 2) are arranged in parallel, and the end surface on the superconducting layer side 4 is fixed to one wide reinforcing tape wire 11. Therefore, the length in the width direction of the superconducting portion 14 (FIG. 2) showing the superconducting characteristics can be shortened, and the eddy current generated when alternating current is applied can be reduced. Furthermore, since the reinforcing tape wire 11 is fixed, the superconducting tape wire 10 and the superconducting coil 50 can be configured to withstand load stress generated in each layer of the thin film superconducting wire 1.

  Furthermore, according to the superconducting tape wire 10 and the superconducting coil 50 using the superconducting tape wire 10, the thickness of the reinforcing tape wire 11 as a reinforcing portion is appropriately set (over 0.020 mm to 0.068 mm or less, more preferably 0.8 mm). By setting to 350 mm or more and 0.065 mm or less, deterioration of the superconducting coil 50 due to the load stress generated in each layer of the thin film superconducting wire 1 can be reduced more effectively than before. That is, it is possible to suppress the occurrence of peeling, deformation, cracks, and the like due to the load stress generated in each layer of the thin film superconducting wire 1 while minimizing the decrease in current density.

  In addition, although several embodiment was described in this specification, these embodiment is shown as an example and this invention is not limited to the said embodiment as it is. That is, in the implementation stage, it is possible to implement in various forms other than the above-described embodiments, and various omissions, additions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1 Thin film superconducting wire (conventional superconducting tape wire)
2 Tape substrate 3 Intermediate layer 4 Superconducting layer 5 Protective layer 6 Stabilizing layer 10 Superconducting tape wire 11 Reinforcing tape wire 12 Brazing material 13 Separating part 15 Insulating tape wire 50 Superconducting coil 51 Winding frame 52 Winding part

Claims (9)

A superconducting portion formed of a superconducting wire whose outer periphery is covered with a highly conductive metal layer;
The superconducting wire that forms the superconducting part is fixed to the outer surface on the superconducting layer side of the superconducting wire.
A superconducting tape wire characterized in that the superconducting portion is provided with a separating portion that divides the superconducting portion into a plurality in the width direction of the superconducting wire and divides the superconducting connection between the sections of the superconducting portion. . The superconducting part is a configuration in which a plurality of superconducting wires are arranged in parallel in the same direction in the width direction of the superconducting wires,
The reinforcing portion is fixed to each of the outer surfaces on the superconducting layer side of the superconducting wires arranged in parallel,
2. The superconducting tape wire according to claim 1, wherein the separating portion is one of an interface and a gap between the superconducting wires. The superconducting tape wire according to claim 1, wherein the outer surface of the superconducting wire on the superconducting layer side and the reinforcing portion are fixed by brazing using a brazing material. The reinforcing tape wire is selected from materials consisting of at least one of stainless steel, copper-beryllium alloy, aluminum, copper, nickel, and copper-nickel alloy. The superconducting tape wire according to the item. 5. The superconducting tape wire according to claim 1, wherein a thickness of the reinforcing tape wire is more than 0.020 mm and 0.068 mm or less. 6. The superconducting tape wire according to claim 5, wherein a thickness of the reinforcing tape wire is not less than 0.350 mm and not more than 0.065 mm. A superconducting portion formed of a superconducting wire whose outer periphery is covered with a highly conductive metal layer, and a reinforcing tape wire fixed to the outer surface of the superconducting wire forming the superconducting portion on the superconducting layer side. With a reinforcing part,
The thickness of the said reinforcement tape wire is more than 0.020mm and 0.068mm or less, The superconducting tape wire characterized by the above-mentioned. 6. The superconducting tape wire according to claim 5, wherein a thickness of the reinforcing tape wire is not less than 0.350 mm and not more than 0.065 mm. A superconducting coil formed by winding the superconducting tape wire according to any one of claims 1 to 8.

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