JP6438342B2 - Superconducting wire and connection structure of superconducting wire - Google Patents

Description

  The present invention relates to a superconducting wire, and more particularly to a superconducting wire including a main body portion including a superconducting material portion and a reinforcing portion that mechanically reinforces the main body portion including the superconducting material portion.

  In applying the superconducting material to the wire, it is necessary to mechanically reinforce the main body including the superconducting material. There is known a superconducting wire including a main body part including a superconducting material part and a reinforcing part for mechanically reinforcing the main body part including the superconducting material part (see Patent Documents 1 to 3).

US Pat. No. 5,801,124 US Pat. No. 6,649,280 International Publication No. 2009/022484

  It is necessary to prepare superconducting wires having different materials, thicknesses, and the like of components (for example, a superconducting material portion and a reinforcing portion) constituting the superconducting wire according to various demands of customers. Therefore, it is necessary to design the material, thickness, etc. of the components constituting the superconducting wire according to various specifications of the superconducting wire required by the customer.

  Conventionally, in response to various requirements for the reinforcing portion of the superconducting wire, a material suitable for the reinforcing portion of the superconducting wire has been searched from various materials each time. However, in accordance with various requirements for the reinforcing portion of the superconducting wire, it is troublesome to search for a material suitable for the reinforcing portion of the superconducting wire from various materials each time.

  In addition, since a material suitable for the requirement for the reinforcing portion of the superconducting wire cannot be found, the design of the superconducting wire has to be reviewed so as to sacrifice some characteristics of the superconducting wire. For this reason, the degree of freedom in designing the superconducting wire has been limited.

  The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to reduce the effort for searching for a material suitable for the reinforcing portion of the superconducting wire and to increase the degree of freedom in designing the superconducting wire. is there.

  A superconducting wire according to an aspect of the present invention includes a main body portion including a superconducting material portion and a reinforcing portion that mechanically reinforces the main body portion including the superconducting material portion. The reinforcing portion is substantially composed of a non-solid-soluble copper-based alloy made of a first material made of copper or a copper-containing alloy and a second material different from the first material. In the present specification, the non-solid-soluble copper-based alloy refers to an alloy in which a second material different from the first material is not dissolved in the first material made of copper or a copper-containing alloy. In this specification, the copper-containing alloy refers to an alloy containing copper and other elements, and the other elements may or may not dissolve in copper. In this specification, being substantially composed of a non-solid-soluble copper-based alloy means that inevitable impurities may be included in addition to the non-solid-soluble copper-based alloy.

  According to the above, it is possible to reduce time and labor for searching for a material suitable for the reinforcing portion of the superconducting wire, and to increase the degree of freedom in designing the superconducting wire.

It is a fragmentary sectional perspective view which shows roughly the structure of the superconducting wire which concerns on Embodiment 1 of this invention. It is a figure which shows the change of the thermal expansion coefficient of copper molybdenum (CuMo) with respect to the mole fraction of copper in copper molybdenum (CuMo) which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the Young's modulus of copper molybdenum (CuMo) with respect to the mole fraction of copper in copper molybdenum (CuMo) which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the thermal expansion coefficient of copper tungsten (CuW) with respect to the molar fraction of copper in copper tungsten (CuW) which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the Young's modulus of copper tungsten (CuW) with respect to the molar fraction of copper in copper tungsten (CuW) which is a non-solid-soluble copper-type alloy. It is a fragmentary sectional perspective view which shows roughly the structure of the superconducting wire which concerns on Embodiment 2 of this invention. It is a fragmentary sectional perspective view which shows roughly the structure of the superconducting wire which concerns on Embodiment 3 of this invention. It is a fragmentary sectional perspective view which shows roughly the structure of the superconducting wire which concerns on Embodiment 4 of this invention. It is a figure which shows the change of the thermal expansion coefficient of a brass molybdenum with respect to the molar fraction of the brass in the brass molybdenum which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the Young's modulus of a brass molybdenum with respect to the molar fraction of the brass in the brass molybdenum which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the thermal expansion coefficient of brass tungsten with respect to the molar fraction of the brass in the brass tungsten which is a non-solid-soluble copper-type alloy. It is a figure which shows the change of the Young's modulus of brass tungsten with respect to the molar fraction of the brass in the brass tungsten which is a non-solid-soluble copper-type alloy. It is sectional drawing which shows roughly the connection structure of the superconducting wire which concerns on Embodiment 5 of this invention.

[Description of Embodiment of the Present Invention]
First, embodiments of the present invention will be listed and described.

  (1) A superconducting wire (1, 10, 10b, 20, 20a, 20b) according to an aspect of the present invention includes a main body part (7, 27) including a superconducting material part (4, 24), a superconducting material part ( 4 and 24) and a reinforcing part (2, 18, 18a, 18b) for mechanically reinforcing the main body part (7, 27). The reinforcing portion (2, 18, 18a, 18b) is substantially composed of a non-solid-soluble copper-based alloy made of a first material made of copper or a copper-containing alloy and a second material different from the first material. Is done.

  In the non-solid soluble copper-based alloy, the first material and the second material do not form a solid solution with each other. Therefore, depending on the ratio of the first material or the ratio of the second material contained in the non-solid-soluble copper-based alloy, the reinforcing portion (2, 18, 18a, The physical properties of 18b) can be continuously changed. Reinforcing the superconducting wire (1, 10, 10b, 20, 20a, 20b) only by changing the ratio of the first material or the second material contained in the reinforcing portion (2, 18, 18a, 18b). Various requests for the parts (2, 18, 18a, 18b) can be met. Therefore, in accordance with various requirements for the reinforcing portion (2, 18, 18a, 18b) of the superconducting wire (1, 10, 10b, 20, 20a, 20b), the reinforcing portion (2 , 18, 18a, 18b) can be saved. Moreover, the freedom degree of design of a superconducting wire (1, 10, 10b, 20, 20a, 20b) can be raised.

(2) In the superconducting wire (1, 10, 10b, 20) according to one aspect of the present invention, either the thermal expansion coefficient of the superconducting material part (4) or the thermal expansion coefficient of the main body part (27) and the reinforcing part (2 , 18, 18a, the difference between the thermal expansion coefficient of 18b) may be equal to or less than 2.0 × 10 ^-6 / K. Thereby, it can suppress that a superconducting wire (1, 10, 10b) warps. Or it can suppress that many cracks and defects arise in the superconducting material part (24) included in the main body part (27) of the superconducting wire (20).

  (3) The superconducting wire (10, 10b) according to one aspect of the present invention further includes a substrate (12) that supports the main body (7), and the reinforcing portion (18, 18a) is opposite to the substrate (12). It may be provided on the main body (7) on the side. Thereby, the main-body part (7) containing a superconducting material part (4) can be mechanically reinforced with a board | substrate (12) and a reinforcement part (18, 18a). Therefore, the mechanical strength of the superconducting wire (10, 10b) can be improved.

(4) In the superconducting wire (10, 10b) according to one aspect of the present invention, the difference between the thermal expansion coefficient of the substrate (12) and the thermal expansion coefficient of the reinforcing body (18, 18a) is 2.0 × 10 ^{−. It} may be ⁶ / K or less. Thereby, it can suppress that a superconducting wire (10, 10b) warps.

  (5) In the superconducting wire (10b, 20, 20a, 20b) according to one aspect of the present invention, the reinforcing portion (18, 18a) is composed of the two main surfaces (7a, 7b, 27a) of the main body portion (7, 27). 27b). Thereby, it can suppress that a superconducting wire (10b, 20, 20a, 20b) warps.

  (6) In the superconducting wire (20) according to one aspect of the present invention, the reinforcing portions (18a, 18b) are configured to apply compressive stress to the main body portion (27) including the superconducting material portion (24). Also good. Thereby, the mechanical strength of the superconducting wire (20) can be improved.

  (7) In the superconducting wire (1, 10, 10b, 20, 20a, 20b) according to one aspect of the present invention, the Young's modulus of the reinforcing portion (2, 18, 18a, 18b) may be 150 GPa or more. . Thereby, the mechanical strength of the superconducting wire (1, 10, 10b, 20, 20a, 20b) can be improved.

(8) In the superconducting wire (1, 10, 10b, 20, 20a, 20b) according to one aspect of the present invention, the first material is at least one selected from the group consisting of copper, brass, bronze, and bronze. It may be made of a material. These materials have a low resistivity of 3.5 × 10 ⁻⁸ (Ωm) or less at the use temperature of the superconducting wire (1, 10, 10b, 20, 20a, 20b) such as liquid nitrogen temperature. . Therefore, the connection between the normal conductor and the superconducting wire (1, 10, 10b, 20, 20a, 20b) for introducing current from the normal conductor to the superconducting wire (1, 10, 10b, 20, 20a, 20b). Heat generation at the connection portion between the superconducting wires and the superconducting wires (1, 10, 10b, 20, 20a, 20b) can be suppressed. Further, when quenching occurs in the superconducting material portion (4, 24), it is possible to prevent the superconducting wire (1, 10, 10b, 20, 20a, 20b) from being blown out.

  (9) In the superconducting wire (1, 10, 10b, 20, 20a, 20b) according to one aspect of the present invention, the second material may have a Young's modulus greater than that of the first material. Therefore, the mechanical strength of the superconducting wire (1, 10, 10b, 20, 20a, 20b) can be improved.

  (10) In the superconducting wire (1, 10, 10b, 20, 20a, 20b) according to one aspect of the present invention, the second material is at least one selected from the group consisting of molybdenum, tungsten, chromium, and cobalt. You may be comprised with an element. These materials have a larger Young's modulus than the first material made of copper or a copper-containing alloy. Therefore, the mechanical strength of the superconducting wire (1, 10, 10b, 20, 20a, 20b) can be improved.

(11) In the superconducting wire (1, 10, 10b, 20, 20a, 20b) according to one aspect of the present invention, the electrical resistivity of the reinforcing portion (2, 18, 18a, 18b) is 3 at the liquid nitrogen temperature. It may be 5 × 10 ⁻⁸ (Ωm) or less. Thereby, the connection part of a normal conductor and a superconducting wire for introducing a current from the normal conductor to the superconducting wire (1, 10, 10b, 20, 20a, 20b), and the superconducting wire (1, 10, 10b, 20, 20a, 20b) can be prevented from generating heat at the connecting portion. Further, when quenching occurs in the superconducting material portion (4, 24), it is possible to prevent the superconducting wire (1, 10, 10b, 20, 20a, 20b) from being blown out.

(12) A superconducting wire connecting structure (30) according to an aspect of the present invention includes a superconducting wire (20a) including reinforcing portions (18a, 18b) having an electrical resistivity of 3.5 × 10 ⁻⁸ (Ωm) or less. , 20b), and the reinforcing portions (18a, 18b) of the plurality of superconducting wires (20a, 20b) may be electrically and mechanically connected to each other. Connection of the superconducting wires having low connection resistance between the plurality of superconducting wires (20a, 20b) by electrically and mechanically connecting the reinforcing portions (18a, 18b) of the plurality of superconducting wires (20a, 20b) to each other. The structure (30) can be obtained.

[Details of the embodiment of the present invention]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
A superconducting wire 1 according to Embodiment 1 will be described with reference to FIG.

  FIG. 1 shows a cross section of superconducting wire 1 according to the present embodiment, cut in a direction intersecting with the direction (longitudinal direction) in which superconducting wire 1 extends. The superconducting current of the superconducting material layer 4 flows along the longitudinal direction of the superconducting wire 1. As shown in FIG. 1, the width direction of the superconducting wire 1 is the x-axis direction, the longitudinal direction is the y-axis direction, and the thickness direction is the z-axis direction.

  Referring to FIG. 1, superconducting wire 1 according to the present embodiment may have a tape shape in which the length in the longitudinal direction is larger than the thickness and the width, and the width is larger than the thickness. . In this specification, the surface (xy plane) extending in the width direction and the longitudinal direction of the superconducting wire is referred to as a main surface.

  Superconducting wire 1 mainly includes a substrate 2 and a main body portion 7. The main body portion 7 may include an intermediate layer 3, a superconducting material layer 4, and a protective layer 5. The intermediate layer 3 and the protective layer 5 are arbitrarily provided. The main body 7 only needs to include at least the superconducting material layer 4. The main body 7 has a first main surface 7a and a second main surface 7b opposite to the first main surface 7a.

  The substrate 2 mechanically supports the main body portion 7 including the superconducting material layer 4. The substrate 2 has a larger thickness than the main body portion 7 including the superconducting material layer 4. The substrate 2 can function as a reinforcing portion that mechanically reinforces the main body portion 7 including the superconducting material layer 4.

  The board | substrate 2 is substantially comprised from the non-solid-solution copper-type alloy which consists of a 1st material which has copper or a copper containing alloy, and a 2nd material different from a 1st material. The non-solid-soluble copper-based alloy refers to an alloy in which a second material different from the first material is not dissolved in the first material made of copper or a copper-containing alloy. As a non-solid-soluble copper-based alloy, a copper-based powder alloy in which a first material made of copper or a copper-containing alloy and a second material different from the first material are produced by a powder alloy method is exemplified. Can do. The non-solid soluble copper-based alloy may be produced by other methods. The fact that the substrate 2 is substantially composed of a non-solid-soluble copper-based alloy means that the substrate 2 may contain inevitable impurities in addition to the non-solid-soluble copper-based alloy.

  The first material included in the substrate 2 may be made of at least one material selected from the group consisting of copper, brass, bronze, and white copper. The copper-containing alloy that is an example of the first material included in the substrate 2 may be made of at least one alloy selected from the group consisting of brass, bronze, and white copper. In the present embodiment, the first material included in the substrate 2 is copper.

The second material included in the substrate 2 is preferably a nonmagnetic element including a weak magnetic element. This is because, since the substrate 2 is located near the superconducting material layer 4, if the substrate 2 has ferromagnetism, it may be difficult to increase the critical current I _c of the superconducting wire 1. Therefore, in the present embodiment, the second material included in the substrate 2 is at least one element selected from the group consisting of molybdenum (Mo), tungsten (W), chromium (Cr), and cobalt (Co). It may be configured.

  As a material of the substrate 2, a non-solid-soluble copper-based alloy of copper tungsten (CuW), a non-solid-soluble copper-based alloy of copper molybdenum (CuMo), a non-solid-soluble copper-based alloy of copper chromium (CuCr), copper cobalt (CuCo) Examples of non-solid-soluble copper alloys, brass tungsten non-solid copper alloys, brass molybdenum non-solid copper alloys, brass chromium non-solid copper alloys, brass cobalt non-solid copper alloys be able to.

  The substrate 2 may have a tape shape with a width of 30 mm, for example. The thickness of the substrate 2 may be adjusted as appropriate according to the purpose, and can usually be in the range of 10 μm to 500 μm. In the present embodiment, the thickness of the substrate 2 is 100 μm. The substrate 2 may be an oriented substrate in which the surface of the substrate made of an insoluble copper-based alloy is oriented and crystallized. An alignment substrate means a substrate in which crystal orientations are aligned in two directions (x direction and y direction) in the plane of the substrate surface. The substrate whose surface is oriented and crystallized may be formed, for example, by attaching an oriented metal film to the surface of the substrate. Examples of the material forming the alignment metal film include nickel tungsten (NiW) and copper (Cu), but are not limited to these materials. When using copper (Cu) as a material constituting the alignment metal film, plating or the like is used to prevent oxidation of the copper (Cu) constituting the alignment metal film in the process after obtaining the alignment substrate. By this method, a coating layer made of Ni (nickel) or the like may be formed on the surface of copper (Cu) constituting the alignment metal film.

The intermediate layer 3 may be formed on the main surface of the substrate 2. The intermediate layer 3 may be made of a material that has extremely low reactivity with the superconducting material layer 4 and does not deteriorate the superconducting characteristics of the superconducting material layer 4. The intermediate layer 3 can be made of a material that prevents metal atoms from flowing out from the substrate 2 to the superconducting material layer 4 when the superconducting material layer 4 is formed using a high-temperature process. The intermediate layer 3 is preferably made of, for example, YSZ (yttria stabilized zirconia), CeO ₂ (cerium oxide), MgO (magnesium oxide), Y ₂ O ₃ (yttrium oxide), Al ₂ O ₃ (aluminum oxide), LaMnO. ₃ (lanthanum manganese oxide) and SrTiO ₃ (strontium titanate).

  The intermediate layer 3 may be composed of a plurality of layers. When the intermediate layer 3 is composed of a plurality of layers, each layer constituting the intermediate layer 3 may be composed of a different material or a part of the same material.

  A superconducting material layer 4 may be formed on the main surface of the intermediate layer 3 opposite to the main surface facing the substrate 2 (upper main surface in FIG. 1). The superconducting material layer 4 is a portion of the superconducting wire 1 through which a superconducting current flows. Superconducting material layer 4 corresponds to the superconducting material portion in the present embodiment. In the present embodiment, the superconducting material layer 4 that is a superconducting material part is a thin film layer substantially composed of a superconducting material.

The superconducting material that can be used for the superconducting material layer 4 is not particularly limited. As a material for the superconducting material layer 4, an RE-123 oxide superconductor may be used. RE-123 oxide superconductor is REBa ₂ Cu ₃ O _y (y is 6-8, more preferably 6.8-7, RE is yttrium, or a rare earth element such as Gd, Sm, or Ho) Means a superconductor represented as In this embodiment, YBa ₂ Cu ₃ O _y (YBCO; y is 6 to 8, more preferably 6.8 to 7) may be used as the RE-123-based oxide superconductor.

In order to improve the critical current I _c , the thickness of the superconducting material layer 4 is preferably 0.5 μm or more. The upper limit value of the thickness of the superconducting material layer 4 is not particularly limited, but is preferably 10 μm or less in consideration of productivity.

  Protective layer 5 may be formed on the main surface of superconducting material layer 4 opposite to the main surface facing intermediate layer 3 (the upper main surface in FIG. 1). The protective layer 5 has a function of protecting the superconducting material layer 4. The protective layer 5 is made of silver (Ag) or a silver alloy. The thickness of the protective layer 5 is preferably 2 μm or less, more preferably 0.05 μm or more and 2 μm or less.

  The stabilization layer 8 may be provided so as to cover the main body portion 7. The stabilization layer 8 only needs to cover at least the first main surface 7 a of the main body 7 and the side surface 7 c of the main body 7. In the present embodiment, the stabilization layer 8 is provided so as to cover the entire circumference of the main body 7 and the substrate 2.

  The stabilization layer 8 is composed of a foil or a plating layer of a highly conductive metal material. The stabilization layer 8 functions together with the protective layer 5 as a bypass through which the current of the superconducting material layer 4 is commutated when the superconducting material layer 4 transitions from the superconducting state to the normal conducting state. The stabilization layer 8 further has a function of protecting the main body portion 7 from external force and moisture. The material constituting the stabilizing layer 8 is preferably, for example, copper or a copper alloy. In order for the stabilization layer 8 to physically protect the protective layer 5 and the superconducting material layer 4, the stabilization layer 8 preferably has a thickness of 10 μm to 500 μm.

The manufacturing method of the superconducting wire 1 of this Embodiment is demonstrated.
First, a step of preparing the substrate 2 is performed. Specifically, a substrate 2 is prepared, which is substantially composed of a non-solid-soluble copper-based alloy composed of a first material having copper or a copper-containing alloy and a second material different from the first material. The The board | substrate 2 can be manufactured by the powder metallurgy method described below, for example. The powder of the first material and the powder of the second material are mixed (mixing step). Next, the mixed powder in which the powder of the first material and the powder of the second material are mixed is compressed and molded to form a molded product (molding process). Thereafter, the molded product is sintered to obtain a substrate 2 substantially composed of a first material having copper or a copper-containing alloy and a non-solid-soluble copper-based alloy different from the first material (sintering step). ).

  Next, a step of forming the intermediate layer 3 on the substrate 2 is performed. Specifically, the intermediate layer 3 is formed on the main surface of the substrate 2. As a method of forming the intermediate layer 3, for example, a physical vapor deposition method such as a sputtering method can be used. If the surface of the substrate 2 is not oriented and crystallized, the oriented intermediate layer 3 may be formed by ion beam assisted deposition (IBAD).

  Next, a step of forming the superconducting material layer 4 on the intermediate layer 3 is performed. In the present embodiment, a RE-123 series oxide superconductor is included on the main surface opposite to the main surface facing the substrate 2 of the intermediate layer 3 (the main surface on the upper side of the intermediate layer 3 in FIG. 1). A superconducting material layer 4 is formed. For example, the superconducting material layer 4 that is a thin film layer may be formed by a vapor deposition method and a liquid deposition method, or a combination thereof. Examples of the vapor deposition method include a pulse laser deposition method (PLD method), a sputtering method, an electron beam evaporation method, a metal organic chemical vapor deposition (MOCVD) method, and a molecular beam epitaxy (MBE) method. As a deposition method using a solution, a metal organic deposition (MOD) method can be exemplified. When the superconducting material layer 4 is formed by at least one of these deposition methods, the superconducting material layer 4 having a surface excellent in crystal orientation and surface smoothness can be formed.

  Next, the process of forming the protective layer 5 on the superconducting material layer 4 is performed. Specifically, it is made of silver (Ag) or a silver alloy on the main surface opposite to the main surface facing the intermediate layer 3 of the superconductive material layer 4 (the main surface on the upper side of the superconductive material layer 4 in FIG. 1). The protective layer 5 is formed. The protective layer 5 may be formed, for example, by physical vapor deposition such as sputtering.

  Thereafter, a step of annealing the main body portion 7 in an oxygen atmosphere is performed. By this annealing step, oxygen is introduced into the superconducting material layer 4. By performing the above steps, the main body 7 including the intermediate layer 3, the superconducting material layer 4, and the protective layer 5 is formed on the substrate 2.

  Finally, a step of forming the stabilization layer 8 so as to cover the main body 7 and the substrate 2 is performed. The stabilization layer 8 only needs to cover at least the first main surface 7a of the main body 7 and the side surface 7c and the side surface of the main body 7. In the present embodiment, the stabilization layer 8 is provided so as to cover the entire circumference of the main body 7 and the substrate 2. For example, the stabilization layer 8 may be formed on the main body 7 and the substrate 2 by a plating method or a method of bonding a foil.

  In addition, in order to adjust the width | variety of a wire, you may perform the process of processing the main-body part 7 and the board | substrate 2 into a thin line between the process of forming the protective layer 5, and the process of forming the stabilization layer 8. FIG. In the process of processing the main body 7 and the substrate 2 into thin lines, the main body 7 and the substrate 2 are thinned to a predetermined width by, for example, performing mechanical slit processing or laser slit processing on the main body 7 and the substrate 2. For example, the thinned main body portion 7 and the substrate 2 can be obtained from one main body portion 7 and the substrate 2 by processing the main body portion 7 and the substrate 2 having a width of 30 mm into a thin wire having a width of 4 mm.

  By carrying out the above steps, superconducting wire 1 according to Embodiment 1 shown in FIG. 1 is manufactured.

The operation and effect of the present embodiment will be described.
In the present embodiment, the substrate 2 (reinforcing portion) that mechanically reinforces the main body portion 7 including the superconducting material layer 4 includes a first material having copper or a copper-containing alloy, and a second material different from the first material. It is substantially comprised from the non-solid-soluble copper-type alloy which consists of these materials. In this non-solid-soluble copper-based alloy, the first material and the second material do not form a solid solution with each other. Therefore, the physical properties of the substrate 2 (reinforcing part) substantially composed of the non-solid-soluble copper-based alloy are determined according to the ratio of the first material or the second material contained in the non-solid-soluble copper-based alloy. Can be changed continuously.

  For example, as shown in FIGS. 2 to 5, the coefficient of thermal expansion and Young's modulus of the non-solid soluble copper-based alloy can be continuously changed according to the molar fraction of copper in the non-solid-soluble copper-based alloy. it can. A portion of the non-solid-soluble copper-based alloy excluding copper is substantially composed of the second material. Therefore, the thermal expansion coefficient and Young's modulus of the substrate 2 substantially composed of the non-solid-soluble copper-based alloy are continuously changed according to the molar fraction of the second material in the non-solid-soluble copper-based alloy. be able to.

  FIG. 2 is a diagram showing a change in the thermal expansion coefficient of copper molybdenum (CuMo) with respect to the mole fraction of copper in copper molybdenum (CuMo), which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the thermal expansion coefficient of copper molybdenum (CuMo) insoluble copper based alloy based on the formula (1). A dotted line is a theoretical line which shows the standard of the minimum of the thermal expansion coefficient of the insoluble copper-type alloy of copper molybdenum (CuMo) based on Formula (2). Formulas (1) and (2) are described in, for example, Koichi Sugimoto and 6 other authors, “Material Histology”, Asakura Shoten, 1997, p. Based on 164-171. A black circle is an actual measurement value of the thermal expansion coefficient of a copper molybdenum (CuMo) insoluble copper-based alloy.

α _u represents the upper limit theoretical line of the thermal expansion coefficient of the non-solid alloy. α _L represents the lower limit theoretical line of the thermal expansion coefficient of the non-solid alloy. α ₁ represents the thermal expansion coefficient of the first material contained in the non-solid alloy. α ₂ represents the thermal expansion coefficient of the second material contained in the non-solid alloy. V _f1 represents the molar fraction of the first material contained in the non-solid alloy. V _f2 represents the molar fraction of the second material contained in the non-solid solution alloy.

  FIG. 3 is a diagram illustrating a change in Young's modulus of copper molybdenum (CuMo) with respect to a mole fraction of copper in copper molybdenum (CuMo), which is a non-solid-soluble copper-based alloy. A solid line is a theoretical line which shows the standard of the upper limit of the Young's modulus of a copper molybdenum (CuMo) insoluble copper-based alloy based on Formula (3). A dotted line is a theoretical line which shows the standard of the lower limit of the Young's modulus of the insoluble copper-type alloy of copper molybdenum (CuMo) based on Formula (4). Expressions (3) and (4) are described in, for example, Koichi Sugimoto and 6 other authors, “Material Histology”, Asakura Shoten, 1997, p. Based on 164-171. A black circle is an actual measurement value of Young's modulus of a non-solid-soluble copper-based alloy of copper molybdenum (CuMo).

E _U represents the theoretical line of the upper limit of the Young's modulus of the non-solid solution alloy. E _L represents the lower limit theoretical line of the Young's modulus of the non-solid alloy. E ₁ represents the Young's modulus of the first material contained in the non-solid alloy. E ₂ represents the Young's modulus of the second material contained in the non-solid alloy. V _f1 represents the molar fraction of the first material contained in the non-solid alloy. V _f2 represents the molar fraction of the second material contained in the non-solid solution alloy.

  Referring to FIG. 2, the actual measurement value is located in the vicinity of the region between the upper limit theoretical line and the lower limit theoretical line. The upper limit theoretical line and the lower limit theoretical line show a tendency for the coefficient of thermal expansion to increase as the molar fraction of copper increases, as in the actual measurement values. Therefore, the upper and lower theoretical lines of the coefficient of thermal expansion of the non-solid-soluble copper-based alloy can serve as a guide for the coefficient of thermal expansion of the non-solid-soluble copper-based alloy with respect to the mole fraction of copper in the non-solid-soluble copper-based alloy. Referring to FIG. 3, the actual measurement value is located near a region between the upper limit theoretical line and the lower limit theoretical line. The upper limit theoretical line and the lower limit theoretical line show a tendency for the Young's modulus to decrease as the molar fraction of copper increases, as in the actual measurement values. Therefore, the upper and lower theoretical lines of Young's modulus of the non-solid-soluble copper-based alloy can be a guide for the Young's modulus of the non-solid-soluble copper-based alloy relative to the molar fraction of copper or copper alloy in the non-solid-soluble copper-based alloy. . As described above, the theoretical line can serve as a guide for the physical property value of the non-solid-soluble copper-based alloy with respect to the mole fraction of copper in the non-solid-soluble copper-based alloy.

Referring to FIG. 1, superconducting wire 1 has substrate 2 only on second main surface 7 b of main body 7, and substrate 2 on first main surface 7 a of main body 7. I don't have it. The superconducting wire 1 has an asymmetric structure with respect to the stacking direction (z direction) of the substrate 2 and the main body 7. Therefore, for example, when the superconducting wire 1 is cooled to room temperature after the manufacturing process of the superconducting wire 1 including a high-temperature manufacturing process is completed, the superconducting wire 1 is caused by a large difference in thermal expansion coefficient between the superconducting material layer 4 and the substrate 2. May warp in the width direction (x direction). When the superconducting wire 1 having a warp in the width direction is wound in a coil shape, the superconducting wire 1 may be broken in the width direction. In particular, as the thickness of the superconducting material layer 4 is increased in order to increase the critical current I _c , the superconducting wire 1 may warp more greatly in the width direction.

In addition to the first material, the substrate 2 includes a second material that does not dissolve in the first material and is different from the first material. Referring to Table 1, the thermal expansion coefficient of copper as the first material in substrate 2 is larger than the thermal expansion coefficient (13.0 × 10 ⁻⁶ / K) of superconducting material layer 4 made of YBCO. . The second material (eg, molybdenum) in the substrate 2 has a smaller coefficient of thermal expansion than the first material (eg, copper) and the superconducting material layer 4 (eg, YBCO). Therefore, by adjusting the ratio of the second material (for example, molybdenum) in the substrate 2 (reinforcing part), the thermal expansion coefficient of the substrate 2 (reinforcing part) is changed to the thermal expansion coefficient of the superconducting material layer 4 (superconducting material part). Can be approached. As a result, the superconducting wire 1 can be prevented from warping.

Referring to FIG. 2, by adjusting the molar fraction of copper as the first material in substrate 2, the heat of substrate 2 substantially composed of a non-solid-soluble copper-based alloy of copper molybdenum (CuMo). The difference between the expansion coefficient and the thermal expansion coefficient (13.0 × 10 ⁻⁶ / K) of the superconducting material layer 4 composed of YBCO is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K or less, more preferably 0.5 × 10 ⁻⁶ / K or less. Furthermore, the thermal expansion coefficient of the substrate 2 can be made equal to the thermal expansion coefficient of the superconducting material layer 4 by adjusting the molar fraction of copper as the first material in the substrate 2. By setting the difference between the thermal expansion coefficient of the substrate 2 and the thermal expansion coefficient of the superconducting material layer 4 to 2.0 × 10 ⁻⁶ / K or less, the superconducting wire 1 can be prevented from warping.

  In addition to the first material, the substrate 2 includes a second material that does not dissolve in the first material and is different from the first material. Referring to Table 1, molybdenum, which is the second material in substrate 2, has a larger Young's modulus than copper, which is the first material in substrate 2. Therefore, the Young's modulus of the substrate 2 can be increased by increasing the proportion of molybdenum that is the second material in the substrate 2. As a result, the mechanical strength of the substrate 2 (reinforcing part) can be improved.

  Referring to FIGS. 2 and 3, substrate 2 that is substantially composed of a non-solid-soluble copper-based alloy of copper molybdenum (CuMo) that can suppress warping of superconducting wire 1 is made of copper or silver. It has a Young's modulus greater than that of stainless steel (SUS) and at least as high as 150 GPa. Therefore, the substrate 2 substantially composed of a non-soluble copper-based alloy of copper molybdenum (CuMo) that can prevent the superconducting wire 1 from warping is provided with the body portion 7 including the superconducting material layer 4 as a machine. It can function as a reinforcing portion that reinforces. The substrate 2 having a Young's modulus equal to or higher than that of stainless steel (SUS) can improve the mechanical strength of the superconducting wire 1. In this specification, the Young's modulus comparable to that of stainless steel (SUS) means a Young's modulus lower by about 20% than stainless steel (SUS), and more specifically means a Young's modulus of 150 GPa.

From the above, when the substrate 2 (reinforcing portion) is required to suppress warping of the superconducting wire 1, the thermal expansion coefficient of the substrate 2 (reinforcing portion) and the thermal expansion of the superconducting material layer 4 (superconducting material portion). The ratio of the first material (copper) or the second material (molybdenum) contained in the substrate 2 (reinforcement part) is adjusted so that the difference from the coefficient is 2.0 × 10 ⁻⁶ / K or less. It is preferable to do.

  FIG. 4 is a diagram showing the change in the thermal expansion coefficient of copper tungsten (CuW) with respect to the molar fraction of copper in copper tungsten (CuW), which is a non-solid soluble copper-based alloy. The solid line is a theoretical line indicating a guideline of the upper limit of the thermal expansion coefficient of the copper tungsten (CuW) insoluble copper-based alloy based on the formula (1). A dotted line is a theoretical line which shows the standard of the minimum of the thermal expansion coefficient of the copper-tungsten (CuW) insoluble copper-type alloy based on Formula (2). As already mentioned, the theoretical line can be a guide for the coefficient of thermal expansion of the non-solid soluble copper-based alloy relative to the molar fraction of copper in the non-solid-soluble copper-based alloy.

  FIG. 5 is a diagram showing a change in Young's modulus of copper tungsten (CuW) with respect to a mole fraction of copper in copper tungsten (CuW) which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the Young's modulus of a copper-tungsten (CuW) insoluble copper-based alloy based on the equation (3). A dotted line is a theoretical line which shows the standard of the lower limit of the Young's modulus of the insoluble copper-type alloy of copper tungsten (CuW) based on Formula (4). As already stated, the theoretical line can be a guide for the change in Young's modulus of a non-solid soluble copper-based alloy relative to the molar fraction of copper in the non-solid-soluble copper-based alloy.

In addition to the first material, the substrate 2 includes a second material that does not dissolve in the first material and is different from the first material. Referring to Table 1, the thermal expansion coefficient of copper as the first material in substrate 2 is larger than the thermal expansion coefficient (13.0 × 10 ⁻⁶ / K) of superconducting material layer 4 made of YBCO. . The second material (eg, tungsten) in the substrate 2 has a smaller coefficient of thermal expansion than the first material (eg, copper) and the superconducting material layer 4 (eg, YBCO). Therefore, by adjusting the ratio of the second material (for example, tungsten) in the substrate 2 (reinforcing part), the thermal expansion coefficient of the substrate 2 (reinforcing part) is changed to the thermal expansion coefficient of the superconducting material layer 4 (superconducting material part). Can be approached. As a result, the superconducting wire 1 can be prevented from warping.

Referring to FIG. 4, by adjusting the molar fraction of copper, which is the first material, in substrate 2, the heat of substrate 2 substantially composed of a copper tungsten (CuW) insoluble copper-based alloy. The difference between the expansion coefficient and the thermal expansion coefficient (13.0 × 10 ⁻⁶ (/ K)) of the superconducting material layer 4 made of YBCO is 2.0 × 10 ⁻⁶ / K or less, preferably 1 0.0 × 10 ⁻⁶ / K or less, more preferably 0.5 × 10 ⁻⁶ / K or less. Furthermore, the thermal expansion coefficient of the substrate 2 can be made equal to the thermal expansion coefficient of the superconducting material layer 4 by adjusting the molar fraction of copper as the first material in the substrate 2. By setting the difference between the thermal expansion coefficient of the substrate 2 and the thermal expansion coefficient of the superconducting material layer 4 to 2.0 × 10 ⁻⁶ / K or less, the superconducting wire 1 can be prevented from warping.

  In addition to the first material, the substrate 2 includes a second material that does not dissolve in the first material and is different from the first material. Referring to Table 1, tungsten, which is the second material in substrate 2, has a Young's modulus greater than that of copper, which is the first material in substrate 2. Therefore, the Young's modulus of the substrate 2 can be increased by increasing the proportion of tungsten that is the second material in the substrate 2. As a result, the mechanical strength of the substrate 2 can be improved.

  Referring to FIGS. 4 and 5, substrate 2 substantially composed of a non-solid-soluble copper-based alloy of copper tungsten (CuW) that can suppress warping of superconducting wire 1 is made of copper or silver. It has a Young's modulus greater than that of stainless steel (SUS) and at least as high as 150 GPa. Therefore, the substrate 2 substantially composed of a copper-tungsten (CuW) non-solid-soluble copper-based alloy that can suppress warping of the superconducting wire 1 is formed by using the body portion 7 including the superconducting material layer 4 as a machine. It can function as a reinforcing portion that reinforces. The substrate 2 having a Young's modulus equal to or higher than that of stainless steel (SUS) can improve the mechanical strength of the superconducting wire 1.

From the above, when the substrate 2 (reinforcing portion) is required to suppress warping of the superconducting wire 1, the thermal expansion coefficient of the substrate 2 (reinforcing portion) and the thermal expansion of the superconducting material layer 4 (superconducting material portion). The ratio of the first material (copper) or the second material (tungsten) contained in the substrate 2 (reinforcing part) is adjusted so that the difference from the coefficient is 2.0 × 10 ⁻⁶ / K or less. It is preferable to do.

  Referring to Table 1, chromium and cobalt, like tungsten and molybdenum, have a smaller thermal expansion coefficient than the first material copper alloy such as copper or brass, and copper such as copper or brass. Has a higher Young's modulus than the alloy. Therefore, the non-solid-soluble copper-based alloy containing the second material made of chromium or cobalt also has the same tendency as the non-solid-soluble copper-based alloy containing the second material made of molybdenum or tungsten shown in FIGS. It is clear that Therefore, it is clear that the superconducting wire 1 can be prevented from warping by using the substrate 2 substantially composed of a non-solid-soluble copper-based alloy containing the second material made of chromium or cobalt. . In addition, substrate 2 substantially composed of a non-solid-soluble copper-based alloy containing a second material made of chromium or cobalt and capable of suppressing warpage of superconducting wire 1 includes superconducting material layer 4. It is obvious that the main body portion 7 can function as a reinforcing portion that mechanically reinforces the main body portion 7.

  As described above, the characteristics (for example, Young's modulus, thermal expansion coefficient) of the substrate 2 (reinforcing portion) substantially composed of the non-solid-soluble copper-based alloy are the same as those contained in the non-solid-soluble copper-based alloy. By changing only the ratio of the first material made of the alloy or the ratio of the second material contained in the non-solid-soluble copper-based alloy (for example, the molar fraction), it can be continuously changed. Therefore, in the superconducting wire 1 of the present embodiment, the ratio of the first material contained in the non-solid-soluble copper-based alloy or the non-solid-soluble copper-based alloy in the substrate 2 substantially composed of the non-solid-soluble copper-based alloy. The substrate 2 (for example, a request to suppress the warpage of the superconducting wire 1) with respect to the substrate 2 (reinforcing portion) of the superconducting wire 1 can be satisfied only by changing the ratio of the second material contained in the substrate 2 ( (Reinforcing part) can be obtained. Therefore, according to various requirements for the substrate 2 (reinforcement portion) of the superconducting wire 1, it is possible to reduce time and effort for searching for a material suitable for the substrate 2 (reinforcement portion) of the superconducting wire 1. The degree of freedom can be increased.

  In the superconducting wire 1 of the present embodiment, the second material contained in the substrate 2 (reinforcing part) does not dissolve in the first material made of copper or a copper-containing alloy contained in the substrate 2. Therefore, the upper limit theoretical line based on Formula (5) and the lower limit theoretical line based on Formula (6) are a first material made of copper or a copper-containing alloy, and a second material different from the first material. It can serve as a guide for the electrical resistivity of the non-solid-soluble copper-based alloy with respect to the molar fraction of the first material in the non-solid-soluble copper-based alloy. Equations (5) and (6) are described in, for example, Koichi Sugimoto and 6 other authors, “Material Histology”, Asakura Shoten, 1997, p. Based on 164-171.

ρ _U represents the upper limit theoretical line of the electrical resistivity of the non-solid alloy. ρ _L represents the lower limit theoretical line of the electrical resistivity of the non-solid alloy. ρ ₁ represents the electrical resistivity of the first material included in the non-solid alloy. ρ ₂ represents the electrical resistivity of the second material contained in the non-solid alloy. V _f1 represents the molar fraction of the first material contained in the non-solid alloy. V _f2 represents the molar fraction of the second material contained in the non-solid solution alloy.

  From Formula (5) and Formula (6), it is substantially comprised from the non-solid-solution copper-type alloy which consists of a 1st material which consists of copper or a copper containing alloy, and a 2nd material different from a 1st material. The electrical resistivity of the substrate 2 (reinforcing portion) has a value between the electrical resistivity of the first material and the electrical resistivity of the second material.

In the superconducting wire 1 of the present embodiment, the first material of the substrate 2 (reinforcing portion) is made of copper or a copper-containing alloy. As a 2nd material of the board | substrate 2 (reinforcement part), molybdenum, tungsten, chromium, and cobalt can be illustrated. Referring to Table 2, the electrical resistivity of the first material and the second material is 3.5 × 10 ⁻⁸ (Ωm) or less at the operating temperature of the superconducting wire 1 (for example, liquid nitrogen temperature of 77K). It is. Therefore, in the present embodiment, the electrical resistivity of the substrate 2 (reinforcing portion) is 3.5 × 10 ⁻⁸ (Ωm) or less.

  Referring to Table 2, at the operating temperature of superconducting wire 1 (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is a stainless steel (SUS) substrate as a comparative example. The electrical resistivity is lower than 1/10. Therefore, at the operating temperature of the superconducting wire 1 (for example, 77 K which is a liquid nitrogen temperature), the substrate 2 (reinforcing portion) of the present embodiment has a lower electrical resistivity than the stainless steel (SUS) substrate which is a comparative example. Have. According to the superconducting wire 1 of the present embodiment, the heat generation at the connecting portion between the normal conductor and the superconducting wire for introducing current from the normal conductor to the superconducting wire 1 and the connecting portion between the superconducting wires 1 is suppressed. Can do. Moreover, according to the superconducting wire 1 of the present embodiment, the superconducting wire 1 is prevented from being melted when a quench occurs in the superconducting material layer 4 (a phenomenon in which the superconducting state suddenly breaks and becomes a normal conducting state). can do.

(Embodiment 2)
With reference to FIG. 6, superconducting wire 10 according to Embodiment 2 will be described. The superconducting wire 10 according to the second embodiment basically has the same configuration as that of the superconducting wire 1 according to the first embodiment shown in FIG. 1, but mainly differs in the following points.

  Superconducting wire 10 of the present embodiment includes substrate 12, main body portion 7, and a reinforcing portion including reinforcing body 18.

  In the present embodiment, as the substrate 12, for example, a substrate made of nickel alloy or silver alloy such as Hastelloy is used. As the substrate 12, a substrate substantially composed of stainless steel or the insoluble copper-based alloy in the first embodiment may be used.

  The main body portion 7 may include an intermediate layer 3, a superconducting material layer 4, and a protective layer 5. The main body 7 includes a first main surface 7a, a second main surface 7b opposite to the first main surface 7a, and a side surface 7c. The main body 7 only needs to include at least the superconducting material layer 4. The intermediate layer 3 is arbitrarily provided. The main body 7 may include a protective layer 5 on the superconducting material layer 4. The protective layer 5 may have a function of protecting the superconducting material layer 4 and further improving the adhesion between the reinforcing body 18 and the superconducting material layer 4 by the joint 16 such as a solder layer. The protective layer 5 may be made of silver (Ag) or a silver alloy.

  Superconducting wire 10 of the present embodiment does not include stabilization layer 8 of the first embodiment. As a modification of the present embodiment, a stabilization layer that covers at least the first main surface 7a and the side surface 7c of the main body 7 may be provided as in the stabilization layer 8 of the first embodiment.

  The reinforcing body 18 is provided on the first main surface 7a of the main body 7, which is the main surface opposite to the second main surface 7b of the main body 7 on the substrate 2 side. The reinforcing body 18 is provided on the main surface of the superconducting material layer 4 opposite to the substrate 2. The reinforcing body 18 is substantially composed of a non-solid-soluble copper-based alloy composed of a first material having copper or a copper-containing alloy and a second material different from the first material. Since the reinforcing body 18 has a Young's modulus equal to or higher than that of stainless steel (SUS) (150 GPa or more), it can function as a reinforcing portion that mechanically reinforces the main body portion 7 including the superconducting material layer 4. The reinforcing body 18 is disposed along the longitudinal direction of the superconducting wire 10. The reinforcing body 18 may have a thickness larger than that of the main body portion 7. The reinforcing body 18 may have a thickness larger than that of the substrate 12.

  The reinforcing body 18 is joined to the main body 7 by a joint 16 such as a solder layer. The protective layer 5 and the joint portion 16 may be further provided on the side surface 7 c of the main body portion 7. The protective layer 5 and the joint portion 16 may be provided so as to cover the entire circumference of the main body portion 7 and the substrate 12.

The operation and effect of the present embodiment will be described.
If the thermal expansion coefficient of the superconducting material layer 4 and the thermal expansion coefficient of the substrate 12 are different, when the superconducting wire is cooled to the operating temperature (for example, 77 K, which is a liquid nitrogen temperature), the superconducting wire may be deformed in the longitudinal direction of the superconducting wire. Sometimes. In the present embodiment, the reinforcing body 18 is provided on the main surface opposite to the substrate 2 of the superconducting material layer 4. The superconducting wire 10 of the present embodiment has a more symmetric structure along the direction along the stacking direction (z direction) of the substrate 12, the main body portion 7, and the reinforcing body 18 than the superconducting wire without the reinforcing body 18. Have. Therefore, according to the superconducting wire 10 of the present embodiment, the superconducting wire 10 can be prevented from warping in the longitudinal direction.

  In the superconducting wire 10 of the present embodiment, the reinforcing body 18 is substantially made of a non-solid-soluble copper-based alloy composed of a first material having copper or a copper-containing alloy and a second material different from the first material. Configured. The physical properties (for example, Young's modulus, thermal expansion coefficient) of the reinforcing body 18 (reinforcing portion) substantially composed of the non-solid-soluble copper-based alloy are determined by the ratio of the first material contained in the non-solid-soluble copper-based alloy or It can be continuously changed by simply changing the ratio of the second material (see FIGS. 2 to 5).

In the superconducting wire 10, the thickness of the main body portion 7 including the superconducting material layer 4 is sufficiently smaller than the thickness of the substrate 12 and the thickness of the reinforcing body 18. Therefore, the difference between the thermal expansion coefficient of the reinforcing body 18 (reinforcing part) and the thermal expansion coefficient of the substrate 12 is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K or less, By adjusting the ratio of the first material or the second material contained in the reinforcing body 18 (reinforcing part) so that it is preferably 0.5 × 10 ⁻⁶ / K or less, the superconducting wire 10 is Warping in the longitudinal direction can be effectively suppressed.

Referring to Table 1, a substrate 12 made of, for example, Hastelloy has a thermal expansion coefficient of 11.2 × 10 ⁻⁶ / K. Referring to FIG. 2, the coefficient of thermal expansion of reinforcing body 18 substantially composed of a non-solid-soluble copper-based alloy of copper molybdenum (CuMo) is obtained by adjusting the molar fraction of copper as the first material. And the thermal expansion coefficient (11.2 × 10 ⁻⁶ / K) of the substrate 12 made of Hastelloy is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K K or less, more preferably 0.5 × 10 ⁻⁶ / K or less. Furthermore, the thermal expansion coefficient of the reinforcing body 18 can be made equal to the thermal expansion coefficient of the substrate 12 by adjusting the molar fraction of copper as the first material. The difference between the thermal expansion coefficient of the reinforcing body 18 and the thermal expansion coefficient of the substrate 12 is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K or less, more preferably 0.5 ×. By setting it to 10 ⁻⁶ / K or less, it is possible to effectively suppress the superconducting wire 10 from warping in the longitudinal direction.

  Referring to FIGS. 2 and 3, the reinforcing body 18 substantially composed of a non-solid-soluble copper-based alloy of copper molybdenum (CuMo) that can suppress warping of the superconducting wire 10 is made of copper and It is larger than the Young's modulus of silver and has a Young's modulus equal to or higher than that of stainless steel (SUS) (150 GPa or higher). Therefore, the reinforcing body 18 substantially composed of a copper molybdenum (CuMo) insoluble copper-based alloy capable of suppressing the superconducting wire 10 from warping in the longitudinal direction is a main body including the superconducting material layer 4. It can function as a reinforcing part that mechanically reinforces the part 7.

From the above, when the reinforcing body 18 (reinforcing part) is required to effectively suppress the superconducting wire 10 from warping in the longitudinal direction, the coefficient of thermal expansion of the substrate 12 and the reinforcing body 18 (reinforcing part). The ratio of the first material (for example, copper) contained in the reinforcing body 18 (reinforcing portion) or the second material (so that the difference from the coefficient of thermal expansion of 2.0 × 10 ⁻⁶ / K or less is For example, it is preferable to adjust the ratio of molybdenum.

  Furthermore, in superconducting wire 10 of the present embodiment, reinforcing body 18 (reinforcing portion) and substrate 2 mechanically reinforce main body portion 7 including superconducting material layer 4 (superconducting material portion). Therefore, superconducting wire 10 of the present embodiment has further improved mechanical strength. In addition, since the neutral line that is the central surface in the stacking direction (z direction) of the substrate 12, the main body portion 7, and the reinforcing body 18 of the superconducting wire 10 according to the present embodiment approaches the superconducting material layer 4, The tensile stress applied to the superconducting material layer 4 when the superconducting wire 10 is bent with the outer side facing outside can be reduced. As a result, the superconducting wire 10 of the present embodiment has a further improved bending strength.

  In the superconducting wire 10 of the present embodiment, the superconducting wire 10 can be obtained simply by changing the ratio of the first material or the second material of the insoluble copper-based alloy contained in the reinforcing body 18 (reinforcing portion). Reinforcing body 18 (reinforcing part) that can respond to various demands on reinforcing body 18 (reinforcing part) (for example, a demand to further improve mechanical strength while suppressing warpage of superconducting wire 10 in the longitudinal direction). Can be obtained. Therefore, the reinforcing body 18 (reinforcing part) substantially composed of a non-solid-soluble copper-based alloy composed of the first material and the second material different from the first material has various requirements for the superconducting wire 10. Accordingly, it is possible to reduce time and effort for searching for a material suitable for the reinforcing body 18 (reinforcing portion) of the superconducting wire 10, and to increase the degree of freedom in designing the superconducting wire 10.

  In the superconducting wire 10 of the present embodiment, the second material contained in the reinforcing body 18 (reinforcing part) is dissolved in the first material made of copper or a copper-containing alloy contained in the reinforcing body 18 (reinforcing part). do not do. Therefore, similarly to the substrate 2 of the first embodiment, the electrical resistivity of the reinforcing body 18 (reinforcing part) of the present embodiment is the electrical resistivity of the first material and the electrical resistivity of the second material. Have a value between.

In superconducting wire 10 of the present embodiment, the first material of reinforcing body 18 (reinforcing portion) is made of copper or a copper-containing alloy. Examples of the second material of the reinforcing body 18 (reinforcing part) include molybdenum, tungsten, chromium, and cobalt. Referring to Table 2, at the operating temperature of superconducting wire 10 (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is 3.5 × 10 ⁻⁸ (Ωm) It is as follows. Therefore, in the present embodiment, the electrical resistivity of the reinforcing body 18 (reinforcing portion) is 3.5 × 10 ⁻⁸ (Ωm) or less.

  Referring to Table 2, at the operating temperature of superconducting wire 10 (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is that of stainless steel (SUS) as a comparative example. It is lower than 1/10 of the electrical resistivity of the reinforcing body. Therefore, the reinforcement body 18 (reinforcement part) of this Embodiment has an electrical resistivity lower than the reinforcement body of the stainless steel (SUS) which is a comparative example. According to the superconducting wire 10 of the present embodiment, the heat generation at the connecting portion between the normal conductor and the superconducting wire for introducing current from the normal conductor to the superconducting wire 10 and the connecting portion between the superconducting wires 10 is suppressed. Can do. Moreover, according to the superconducting wire 10 of the present embodiment, it is possible to prevent the superconducting wire 10 from being melted when quenching occurs in the superconducting material layer 4.

(Embodiment 3)
With reference to FIG. 7, superconducting wire 10b according to Embodiment 3 will be described. The superconducting wire 10b of the third embodiment basically has the same configuration as that of the superconducting wire 10 of the second embodiment shown in FIG. 6 and can obtain the same effects, but mainly in the following points. Different.

  The superconducting wire 10b of the present embodiment includes a substrate 12, a main body 7, and a reinforcing portion including a first reinforcing body 18a and a second reinforcing body 18b.

  The first reinforcing body 18 a is provided on the first main surface 7 a of the main body portion 7. The second reinforcing body 18 b is provided on the second main surface 7 b of the main body portion 7. The second reinforcing body 18b is provided on the main surface of the superconducting material layer 4 on the side opposite to the first reinforcing body 18a. The reinforcing portion (first reinforcing body 18a, second reinforcing body 18b) of the present embodiment is composed of a first material having copper or a copper-containing alloy and a second material different from the first material. It is substantially composed of a non-solid soluble copper-based alloy. Since the first reinforcing body 18a and the second reinforcing body 18b have a Young's modulus equal to or higher than that of stainless steel (SUS) (150 GPa or higher), the main body portion 7 including the superconducting material layer 4 is mechanically reinforced. It can function as a reinforcing part. The first reinforcing body 18a may have the same thickness and the same thermal expansion coefficient as the second reinforcing body 18b. The first reinforcing body 18 a and the second reinforcing body 18 b may have a thickness larger than that of the main body portion 7. The reinforcing body 18 may have a thickness larger than that of the substrate 12.

  The first reinforcing body 18a may be provided on the first main surface 17a of the main body portion 17 by a joint portion 16 such as a solder layer. The second reinforcing body 18b may be provided on the second main surface 17b of the main body portion 17 by a joint portion 16 such as a solder layer. The fact that the second reinforcing body 18b is provided on the second main surface 17b of the main body 17 means that another member may be interposed between the second reinforcing body 18b and the main body 17. Means. Specifically, the second reinforcing body 18 b is provided on the main surface of the substrate 12 provided on the second main surface 17 b of the main body portion 17.

  The main body 7 may include a protective layer 5 on the superconducting material layer 4. The protective layer 5 may have a function of protecting the superconducting material layer 4 and further improving the adhesion between the first reinforcing body 18a and the superconducting material layer 4 by the joint 16 such as a solder layer. The protective layer 5 may be made of silver (Ag) or a silver alloy. In order to improve the adhesion between the second reinforcing body 18 b and the substrate 12 by the joint portion 16 such as a solder layer, the base layer 15 is formed on the main surface of the substrate 12, and the joint portion 16 is formed on the base layer 15. May be provided. The underlayer 15 may be made of silver (Ag) or a silver alloy, like the protective layer 5. The protective layer 5 and the joint portion 16 may be further provided on the side surface 7 c of the main body portion 7. The protective layer 5 and the joint portion 16 may be provided so as to cover the entire circumference of the main body portion 7 and the substrate 12.

  As the substrate 12, a substrate substantially composed of stainless steel (SUS), Hastelloy, or the non-solid-soluble copper-based alloy in the first embodiment can be used.

The operation and effect of the present embodiment will be described.
If the thermal expansion coefficient of the superconducting material layer 4 and the thermal expansion coefficient of the substrate 12 are different, when the superconducting wire is cooled to the operating temperature (for example, 77 K, which is a liquid nitrogen temperature), the superconducting wire may be deformed in the longitudinal direction of the superconducting wire. Sometimes. In the present embodiment, the second reinforcing body 18b is provided on the main surface of the superconducting material layer 4 opposite to the first reinforcing body 18a. In the superconducting wire 10b of the present embodiment, the neutral wire that is the central surface in the stacking direction (z direction) of the first reinforcing body 18a, the main body portion 7, the substrate 12, and the second reinforcing body 18b is the superconducting material layer. 4, the superconducting wire 10b of the present embodiment has a first reinforcing body 18a, a main body portion 7, a substrate 12, and a superconducting wire that does not have the first reinforcing body 18a and the second reinforcing body 18b. The second reinforcing body 18b has a more symmetrical structure along the direction along the stacking direction (z direction). Therefore, according to the superconducting wire 10b of the present embodiment, it is possible to suppress the superconducting wire 10b from warping in the longitudinal direction.

Similar to the superconducting wire 10 of the second embodiment, in the superconducting wire 10b of the present embodiment, the difference between the thermal expansion coefficient of the first reinforcing body 18a and the thermal expansion coefficient of the substrate 12, and the second reinforcing body. The difference between the thermal expansion coefficient of 18b and the thermal expansion coefficient of the substrate 12 is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K or less, more preferably 0.5 × 10 ⁻ The ratio of the first material contained in the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) substantially composed of the non-solid-soluble copper-based alloy so as to be ⁶ / K or less, or the first The ratio of the two materials may be adjusted. For this reason, it can suppress effectively that the superconducting wire 10b warps in a longitudinal direction.

In the superconducting wire 10b of the present embodiment, the second reinforcing body 18b is provided on the main surface of the superconducting material layer 4 opposite to the first reinforcing body 18a. The first reinforcing body 18a may have the same thickness as the second reinforcing body 18b. The difference between the coefficient of thermal expansion of the first reinforcing body 18a and the coefficient of thermal expansion of the second reinforcing body 18b is 2.0 × 10 ⁻⁶ / K or less, preferably 1.0 × 10 ⁻⁶ / K or less, More preferably, it may be 0.5 × 10 ⁻⁶ / K or less. The first reinforcing body 18a may have the same thermal expansion coefficient as that of the second reinforcing body 18b. In the superconducting wire 10b of the present embodiment, the neutral wire that is the central surface in the stacking direction (z direction) of the first reinforcing body 18a, the main body portion 7, the substrate 12, and the second reinforcing body 18b is the superconducting material layer. 4, the superconducting wire 10b of the present embodiment is further symmetric along the direction along the stacking direction (z direction) of the first reinforcing body 18a, the main body 7, the substrate 12, and the second reinforcing body 18b. It has a simple structure. The warpage in the longitudinal direction of the superconducting wire 10b caused by the difference between the thermal expansion coefficient of the first reinforcing body 18a and the thermal expansion coefficient of the substrate 12 is the thermal expansion coefficient of the second reinforcing body 18b and the thermal expansion coefficient of the substrate 12. Is canceled by the warp in the longitudinal direction of the superconducting wire 10b due to the difference between the two. Therefore, according to the superconducting wire 10b of the present embodiment, the difference between the thermal expansion coefficient of the first reinforcing body 18a and the thermal expansion coefficient of the substrate 12, and the thermal expansion coefficient of the second reinforcing body 18b and the board 12 Even if the difference from the thermal expansion coefficient is larger than 2.0 × 10 ⁻⁶ / K, the superconducting wire 10 b can be prevented from warping in the longitudinal direction.

As described above, the difference between the thermal expansion coefficient of the first reinforcing body 18a and the thermal expansion coefficient of the substrate 12 and the difference between the thermal expansion coefficient of the second reinforcing body 18b and the thermal expansion coefficient of the substrate 12 are 2 It may be larger than 0.0 × 10 ⁻⁶ / K. Therefore, the first reinforcing body 18a and the second reinforcing body 18b are substantially composed of a non-solid-soluble copper-based alloy so as to have a Young's modulus of 150 GPa or more, preferably 182 GPa or more, and more preferably 205 GPa or more. The mechanical strength of the superconducting wire 10b is further improved by adjusting the ratio of the first material or the ratio of the second material included in the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b). May be.

The superconducting wire 10b of the first mounting example has, for example, a stainless steel (SUS) substrate 12 having a thermal expansion coefficient of 17.3 × 10 ⁻⁶ / K and a molar fraction of the first material (Cu). For example, a first reinforcing body 18a and a second reinforcing body 18b that are substantially composed of 80% or less of copper molybdenum (CuMo) insoluble copper-based alloy are provided. As shown in FIGS. 2 and 3, according to the superconducting wire 10b of the first mounting example, the warp of the superconducting wire 10b can be suppressed, and the first reinforcing body 18a and the second reinforcing body 18b. Can be made larger than the Young's modulus of stainless steel (SUS).

In the superconducting wire 10b of the second mounting example, for example, the molar fraction of the Hastelloy substrate 12 having a thermal expansion coefficient of 11.2 × 10 ⁻⁶ / K and the first material (Cu) is, for example, 50% or less. The first reinforcing body 18a and the second reinforcing body 18b substantially composed of a copper-tungsten (CuW) insoluble copper-based alloy are provided. As shown in FIGS. 4 and 5, according to the superconducting wire 10b of the first mounting example, the warp of the superconducting wire 10b can be suppressed, and the first reinforcing body 18a and the second reinforcing body 18b. The Young's modulus of can be made larger than the Young's modulus of Hastelloy.

  Each of the first reinforcing body 18a and the second reinforcing body 18b preferably has a thickness equal to or greater than the sum of the thickness of the main body portion 7 and the thickness of the substrate 12. When each of the first reinforcing body 18a and the second reinforcing body 18b has a thickness equal to or greater than the sum of the thickness of the main body 7 and the thickness of the substrate 12, the main body against the warp of the superconducting wire 10b. 7 and the contribution of the substrate 12 are reduced, and the warpage of the superconducting wire 10b can be further effectively suppressed.

  Furthermore, in the superconducting wire 10b of the present embodiment, the first reinforcing body 18a, the second reinforcing body 18b, and the substrate 2 mechanically reinforce the main body portion 7 including the superconducting material layer 4. Therefore, the superconducting wire 10b of the present embodiment has further improved mechanical strength.

  In superconducting wire 10b of the present embodiment, the ratio of the first material or the ratio of the second material of the non-solid-soluble copper-based alloy contained in the reinforcing portion (first reinforcing body 18a and second reinforcing body 18b). It is possible to suppress various demands on the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) of the superconducting wire 10b (for example, the superconducting wire 10b is prevented from warping in the longitudinal direction and superconducting. It is possible to obtain a reinforcing portion (first reinforcing body 18a and second reinforcing body 18b) that can meet the demand for further improving the mechanical strength of the wire 10b. Therefore, the reinforcement part (the 1st reinforcement body 18a and the 2nd reinforcement body 18b) substantially comprised from the non-solid-soluble copper-type alloy which consists of a 1st material and a 2nd material different from a 1st material. ) Can reduce the effort to search for a material suitable for the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) of the superconducting wire 10b according to various requirements for the superconducting wire 10b. The degree of freedom in designing the wire 10b can be increased.

  In the superconducting wire 10b of the present embodiment, the second material contained in the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) is the reinforcing portion (the first reinforcing body 18a and the second reinforcing body). It does not dissolve in the first material made of copper or copper-containing alloy contained in the body 18b). Therefore, like the reinforcing portion (reinforcing body 18) of the second embodiment, the electrical resistivity of the reinforcing portion (first reinforcing body 18a and second reinforcing body 18b) of the present embodiment is the first material. And an electrical resistivity of the second material.

In the present embodiment, the first material of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) is made of copper or a copper-containing alloy. As the second material of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b), molybdenum, tungsten, chromium, and cobalt can be exemplified. Referring to Table 2, at the operating temperature of superconducting wire 10b (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is 3.5 × 10 ⁻⁸ (Ωm) or less. It is. For this reason, in the present embodiment, the electrical resistivity of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) is 3.5 × 10 ⁻⁸ (Ωm) or less.

  Referring to Table 2, at the operating temperature of superconducting wire 10b (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is a reinforcement of stainless steel (SUS) as a comparative example. Lower than 1/10 of the body's electrical resistivity. Therefore, the reinforcement part (1st reinforcement body 18a and 2nd reinforcement body 18b) of this Embodiment has an electrical resistivity lower than the reinforcement body of the stainless steel (SUS) which is a comparative example. According to the superconducting wire 10b of the present embodiment, the heat generation at the connecting portion between the normal conductor and the superconducting wire for introducing current from the normal conductor to the superconducting wire 10b and the connecting portion between the superconducting wires 10b is suppressed. Can do. Moreover, according to the superconducting wire 10b of the present embodiment, it is possible to prevent the superconducting wire 10b from being melted when quenching occurs in the superconducting material layer 4.

(Embodiment 4)
A superconducting wire 20 according to Embodiment 4 will be described with reference to FIG. The superconducting wire 20 according to the present embodiment includes a main body portion 27 and reinforcing portions (first reinforcing body 18a and second reinforcing body 18b). The main body portion 27 includes a superconducting material portion made of the superconducting material 24 and a sheath portion 26 that covers the superconducting material 24.

  The superconducting material 24 is a portion in the superconducting wire 20 through which a superconducting current flows. In the present embodiment, the superconducting material 24 is composed of a plurality of superconducting filaments. Superconducting material 24 may be composed of a single superconducting filament. An example of the material of the superconducting material 24 is a bismuth-based oxide superconductor. The bismuth-based oxide superconductor means a superconductor having a Bi-Pb-Sr-Ca-Cu-O-based composition. More specifically, the material of the superconducting material 24 includes a Bi2223 phase in which the atomic ratio of (bismuth and lead): strontium: calcium: copper is approximated at a ratio of 2: 2: 2: 3. Can be used.

  The sheath portion 26 embeds the superconducting material 24. The sheath portion 26 increases the mechanical strength such as the tensile strength of the superconducting wire 20 and imparts flexibility to the superconducting wire 20. The sheath portion 26 further has a function of improving the adhesiveness between the first reinforcing body 18a and the main body portion 27 and the adhesiveness between the second reinforcing body 18b and the main body portion 27 by the joining portion 16 such as a solder layer. You may have. Examples of the material of the sheath portion 26 include silver and a silver alloy.

  The reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) are provided on at least one of the first main surface 27a and the second main surface 27b of the main body portion 27. In the present embodiment, the first reinforcement body 18 a is provided on the first main surface 27 a of the main body portion 27, and the second reinforcement body 18 b is provided on the second main surface 27 b of the main body portion 27. It has been. The second reinforcing body 18 b is provided on the main surface of the main body portion 27 including the superconducting material 24 on the side opposite to the first reinforcing body 18 a. The reinforcing portions (first reinforcing body 18a and second reinforcing body 18b) of the present embodiment are similar to the reinforcing portions (first reinforcing body 18a and second reinforcing body 18b) of the third embodiment. It is substantially comprised from the non-solid-soluble copper-type alloy which consists of a 1st material which has copper or a copper containing alloy, and a 2nd material different from a 1st material. The first reinforcing body 18a and the second reinforcing body 18b have a Young's modulus equal to or higher than stainless steel (SUS) (150 GPa or higher). Therefore, the first reinforcing body 18 a and the second reinforcing body 18 b can function as a reinforcing portion that mechanically reinforces the main body portion 27 including the superconducting material layer 4. The first reinforcing body 18a may have the same thickness and the same thermal expansion coefficient as the second reinforcing body 18b.

  The 1st material contained in the 1st reinforcement body 18a and the 2nd reinforcement body 18b may be comprised with at least 1 type of material chosen from the group which consists of copper, brass, bronze, and white bronze. The copper-containing alloy which is an example of the first material included in the first reinforcing body 18a and the second reinforcing body 18b is made of at least one alloy selected from the group consisting of brass, bronze, and bronze. .

  The reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) may be joined to the main body portion 27 by the joining portion 16 such as a solder layer. Specifically, the first reinforcing body 18a is joined to the first main surface 27a of the main body portion by the joint portion 16, and the second reinforcing body 18b is joined to the second main surface 27b of the main body portion. May be joined. The joint portion 16 such as a solder layer may also be provided on the side surface 27 c of the main body portion 27.

A method for manufacturing the superconducting wire 20 of the present embodiment will be described.
First, a step of preparing a tape-shaped main body 27 having the superconducting material 24 is performed. Specifically, raw material powder of oxide or carbonate is mixed so that Bi, Pb, Sr, Ca and Cu have a predetermined composition ratio. Precursor powder is produced by repeating heat treatment and pulverization of this mixed powder.

  Next, the precursor powder is filled into a metal tube. Thereafter, wire drawing is performed on the metal tube filled with the precursor powder. In this wire drawing process, the wire drawing and the intermediate softening treatment are repeated to obtain a clad wire covered with a metal tube using the precursor filament as a core material.

  Next, a plurality of clad wires are bundled and fitted again into the metal tube. Thereby, for example, a multi-core wire having 55 cores is produced. Next, the multifilamentary wire is drawn. Thereby, the wire which has the form which coat | covered the precursor powder of the oxide superconductor with the sheath part 26 is produced.

  Thereafter, a plurality of rolling processes and heat treatments are repeated for the multifilamentary wire. As a result, the precursor powder changes to become a superconducting material 24 composed of a plurality of superconducting filaments. Moreover, a wire becomes tape-like by rolling. Through the above steps, a tape-shaped main body 27 having the superconducting material 24 and the sheath portion 26 covering the superconducting material 24 is manufactured.

  Next, a step of preparing the reinforcing body 18 is performed. Specifically, it is substantially composed of a non-solid-soluble copper-based alloy composed of a first material having copper or a copper-containing alloy and a second material dispersed without dissolving in the first material. A reinforcing body 18 is prepared. The reinforcing body 18 can be manufactured by a method similar to that of the substrate 2 of the first embodiment, such as powder metallurgy.

  Then, the process of providing the reinforcement part (the 1st reinforcement body 18a and the 2nd reinforcement body 18b) in at least one of the 1st main surface 27a and the 2nd main surface 27b of the main-body part 27 is implemented. The main body 27 and the reinforcing part (the first reinforcing body 18a and the second reinforcing body 18b) are joined by the joining part 16 such as a solder layer. Through the above steps, the superconducting wire 20 shown in FIG. 8 is obtained.

Next, the operation and effect of the present embodiment will be described.
In the superconducting wire 20 of the present embodiment, the first reinforcing body 18a and the second reinforcing body 18b mechanically reinforce the main body 27 including the superconducting material 24. Therefore, the superconducting wire 20 of the present embodiment has improved mechanical strength.

  In the present embodiment, the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) for mechanically reinforcing the main body portion 27 including the superconducting material portion (superconducting material 24) are copper or copper-containing It is substantially comprised from the non-solid-solution copper-type alloy which consists of the 1st material which has an alloy, and the 2nd material different from a 1st material. In this non-solid-soluble copper-based alloy, the first material and the second material do not form a solid solution with each other. Therefore, according to the proportion of the first material or the second material contained in the non-solid-soluble copper-based alloy, a reinforcing portion that is substantially composed of the non-solid-soluble copper-based alloy (for example, the first reinforcement) The physical properties of the body 18a and the second reinforcing body 18b) can be continuously changed.

  For example, as shown in FIGS. 2 to 5, the coefficient of thermal expansion and Young's modulus of the non-solid soluble copper-based alloy can be continuously changed according to the molar fraction of copper in the non-solid-soluble copper-based alloy. it can. Further, as shown in FIGS. 9 to 12, the thermal expansion coefficient and Young's modulus of the non-solid-soluble copper-based alloy can be continuously changed according to the molar fraction of brass in the non-solid-soluble copper-based alloy. it can. A portion of the non-solid-soluble copper-based alloy excluding copper or brass is substantially composed of the second material. Therefore, the thermal expansion coefficient and Young's modulus of the non-solid soluble copper-based alloy can be continuously changed according to the molar fraction of the second material in the non-solid-soluble copper-based alloy.

  FIG. 9 is a diagram showing changes in the thermal expansion coefficient of brass molybdenum with respect to the molar fraction of brass in brass molybdenum, which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the thermal expansion coefficient of a non-solid-soluble copper-based alloy of brass molybdenum based on the formula (1). A dotted line is a theoretical line which shows the standard of the minimum of the thermal expansion coefficient of the non-soluble copper-type alloy of brass molybdenum based on Formula (2).

  FIG. 10 is a diagram showing a change in Young's modulus of brass molybdenum with respect to the mole fraction of brass in brass molybdenum which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the Young's modulus of a non-solid copper alloy of brass molybdenum based on the formula (3). A dotted line is a theoretical line which shows the standard of the lower limit of the Young's modulus of the non-solution-soluble copper-type alloy of brass molybdenum based on Formula (4).

  FIG. 11 is a diagram showing a change in the thermal expansion coefficient of brass tungsten with respect to the molar fraction of brass in brass tungsten which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the thermal expansion coefficient of a non-solid copper-based alloy of brass tungsten based on the formula (1). A dotted line is a theoretical line which shows the standard of the minimum of the thermal expansion coefficient of the non-solution-soluble copper-type alloy of brass tungsten based on Formula (2).

  FIG. 12 is a diagram showing a change in Young's modulus of brass tungsten with respect to the mole fraction of brass in brass tungsten which is a non-solid-soluble copper-based alloy. The solid line is a theoretical line indicating a guideline for the upper limit of the Young's modulus of a non-solid-soluble copper-based alloy of brass tungsten based on the formula (3). A dotted line is a theoretical line which shows the standard of the minimum of the Young's modulus of the non-solution-soluble copper-type alloy of brass tungsten based on Formula (4).

  As described above, the theoretical lines shown in FIGS. 2 to 5 and 9 to 12 show the physical properties of the non-solid-soluble copper-based alloy with respect to the molar fraction of copper or the copper alloy in the non-solid-soluble copper-based alloy. Can be a value guide.

  In the superconducting wire 20 of the present embodiment, a material containing a Bi2223 phase is used as the superconducting material 24. The material containing the Bi2223 phase is ceramics. In general, ceramics have high strength against compressive stress but low strength against tensile stress. Therefore, the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) may be configured to apply a compressive stress to the main body portion 27 including the superconducting material 24. Thereby, the mechanical strength of the superconducting wire 20 can be improved.

  In order to configure the reinforcing portion so as to apply a compressive stress to the main body portion 27 including the superconducting material 24, for example, the reinforcing portion may have a larger thermal expansion coefficient than the main body portion 27 including the superconducting material 24. When the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) have a larger thermal expansion coefficient than the main body portion 27 including the superconducting material 24, the superconducting wire 20 is used at the operating temperature (for example, at the liquid nitrogen temperature). When being cooled to 77 K), the reinforcing portions (for example, the first reinforcing body 18 a and the second reinforcing body 18 b) contract more than the main body portion 27. Therefore, compressive stress can be applied to the main body portion 27 including the superconducting material 24 by the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b). As a result, the mechanical strength of the superconducting wire 20 can be improved.

Referring to FIG. 2, FIG. 4, FIG. 9, and FIG. 11, copper molybdenum (CuMo), copper tungsten (CuW) are adjusted by adjusting the molar fraction of the first material copper alloy such as copper or brass. ), The thermal expansion coefficient of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) substantially made of brass molybdenum or a non-solid-soluble copper-based alloy of brass tungsten, and the superconductivity including the Bi2223 phase. The coefficient of thermal expansion (12.6 × 10 ⁻⁶ / K) of the main body 27 including the material 24 can be made larger.

  Referring to FIGS. 2 to 5 and FIGS. 9 to 12, the thermal expansion coefficient of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) is the thermal expansion of the main body portion 27 including the superconducting material 24. The reinforcing part (the first reinforcing body 18a and the second reinforcing body 18b), which can be larger than the coefficient, is larger than the Young's modulus of copper, a copper alloy such as brass, silver, and stainless steel (SUS). And a Young's modulus equal to or higher than (150 GPa or higher). Therefore, the reinforcing parts (the first reinforcing body 18a and the second reinforcing body 18b) having a larger thermal expansion coefficient than the main body part 27 including the superconducting material 24 mechanically reinforces the main body part 27 including the superconducting material 24. It can function as a reinforcing part. In order to further improve the mechanical strength of the superconducting wire 20, the Young's modulus of the first reinforcing body 18a and the second reinforcing body 18b is preferably greater than or equal to the Young's modulus of 182 GPa stainless steel (SUS), more preferably 205 GPa. It may be greater than the Young's modulus of Hastelloy.

  From the above, when the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) are required to improve the mechanical strength of the superconducting wire 20, for example, the reinforcing portion (the first reinforcing body). 18a and the second reinforcing body 18b) by making the coefficient of thermal expansion larger than that of the main body 27 including the superconducting material 24, the reinforcing part (the first reinforcing body 18a and the second reinforcing body 18b). However, it is preferable to apply compressive stress to the superconducting material part (superconducting material 24).

In addition, if the difference between the thermal expansion coefficient of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) and the thermal expansion coefficient of the main body portion 27 including the superconducting material 24 is too large, the superconducting material 24 has many. May have cracks or defects. Therefore, the difference between the thermal expansion coefficient of the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) and the thermal expansion coefficient of the main body 27 including the superconducting material 24 is 2.0 × 10 ⁻⁶ / K. The following is preferred. The difference between the thermal expansion coefficient of the reinforcing part (the first reinforcing body 18a and the second reinforcing body 18b) and the thermal expansion coefficient of the main body part 27 including the superconducting material 24 is set to 2.0 × 10 ⁻⁶ / K or less. As a result, the occurrence of many cracks and defects in the superconducting material 24 can be suppressed.

  In order to configure the reinforcing portion so as to apply compressive stress to the main body portion 27 including the superconducting material 24, for example, tensile stress may be applied to the reinforcing portion in advance. Specifically, the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) to which tensile stress is applied are joined to the main body portion 27 including the superconducting material 24. Then, this tensile stress is removed. Since the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) from which the tensile stress has been removed contract, the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) A compressive stress can be applied to the main body 27 including the superconducting material 24. When compressive stress is applied to the main body 27 including the superconducting material 24 by applying tensile stress in advance to the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b), the reinforcing portion (for example, The thermal expansion coefficients of the first reinforcing body 18 a and the second reinforcing body 18 b) may be smaller than the thermal expansion coefficient of the main body portion 27 including the superconducting material 24. Even if the tensile stress due to the difference between the thermal expansion coefficient of the reinforcing part (for example, the first reinforcing body 18a and the second reinforcing body 18b) and the thermal expansion coefficient of the main body part 27 including the superconducting material 24 is taken into consideration, the reinforcing part The reinforcing portion is made so that the superconducting wire 20 has sufficient mechanical strength by the compressive stress applied to the main body portion 27 including the superconducting material 24 by the first reinforcing body 18a and the second reinforcing body 18b (for example, the first reinforcing body 18a and the second reinforcing body 18b). For example, the ratio of the first material or the second material included in the first reinforcing body 18a and the second reinforcing body 18b may be adjusted.

In the first mounting example in which compressive stress is applied to the main body 27 including the superconducting material 24, the superconducting wire 20 has a main body 27 having a thickness of 0.23 mm and a width of 4.3 mm, a thickness of 50 μm, and a thickness of 4. And a reinforcing portion (first reinforcing body 18a, second reinforcing body 18b) of a non-solid alloy of brass molybdenum having a width of 5 mm (molybdenum mole fraction of 30%). The reinforcement part (the first reinforcement body 18a and the second reinforcement body 18b) of the non-solid alloy of molybdenum molybdenum (mol fraction of molybdenum 30%) applies a compressive strain of 0.1% to the main body part 27. To do. The superconducting wire 20 of the first mounting example has an allowable stress of about 400 MPa. Here, the allowable stress means a stress in which the critical current I _c when the allowable stress is applied to the superconducting wire is 95% of the critical current I _c when no stress is applied to the superconducting wire. It is one of the indicators of sexual strength. In contrast, the superconducting wire of the first comparative example has the same thickness and width as the main body 27 and the reinforcing portions (first reinforcing body 18a and second reinforcing body 18b) of the first mounting example. And a reinforcing portion made of a solid solution copper alloy. The superconducting wire of the first comparative example has an allowable stress of 250 MPa. The superconducting wire 20 of the first mounting example has an allowable stress of about 1.6 times that of the superconducting wire of the first comparative example. The superconducting wire 20 of the first mounting example has improved mechanical strength compared to the superconducting wire of the first comparative example.

  In the second mounting example in which compressive stress is applied to the main body 27 including the superconducting material 24, the superconducting wire 20 has a main body 27 having a thickness of 0.23 mm and a width of 4.3 mm, a thickness of 20 μm, and a thickness of 4 μm. And a reinforcing portion (first reinforcing body 18a, second reinforcing body 18b) of a non-solid alloy of brass molybdenum having a width of 5 mm (molybdenum mole fraction of 30%). The reinforcement part (the first reinforcement body 18a and the second reinforcement body 18b) of the non-solid alloy of molybdenum molybdenum (molybdenum mole fraction of 30%) applies a compressive strain of 0.15% to the main body part 27. To do. The superconducting wire 20 of the second mounting example has an allowable stress of about 400 MPa. In contrast, the superconducting wire of the second comparative example has the same thickness and width as the main body 27 and the reinforcing portions (first reinforcing body 18a and second reinforcing body 18b) of the second mounting example. And a reinforcing portion made of stainless steel (SUS). The superconducting wire of the second comparative example has an allowable stress of 270 MPa. The superconducting wire 20 of the second mounting example has an allowable stress approximately 1.5 times that of the superconducting wire of the second comparative example. The superconducting wire 20 of the second mounting example has improved mechanical strength compared to the superconducting wire of the second comparative example.

  In the third mounting example in which compressive stress is applied to the main body 27 including the superconducting material 24, the superconducting wire 20 has a main body 27 having a thickness of 0.23 mm and a width of 4.3 mm, a thickness of 30 μm, and a thickness of 4 μm. And a reinforcing portion (first reinforcing body 18a, second reinforcing body 18b) of a non-solid alloy of brass molybdenum having a width of 5 mm (molybdenum mole fraction of 30%). The reinforcement part (the first reinforcement body 18a and the second reinforcement body 18b) of the non-solid alloy of molybdenum molybdenum (molar fraction of molybdenum 30%) applies a compression strain of 0.20% to the main body 27. To do. The superconducting wire 20 of the third mounting example has an allowable stress of about 450 MPa. In contrast, the superconducting wire of the third comparative example has the same thickness and width as the main body 27 and the reinforcing portions (the first reinforcing body 18a and the second reinforcing body 18b) of the third mounting example. And a reinforcing portion made of a Ni alloy. The superconducting wire of the third comparative example has an allowable stress of about 400 MPa. The superconducting wire 20 of the third mounting example has an allowable stress of about 1.1 times that of the superconducting wire of the third comparative example. The superconducting wire 20 of the third mounting example has improved mechanical strength compared to the superconducting wire of the third comparative example.

  Referring to Table 1, chromium and cobalt, like tungsten and molybdenum, have a smaller coefficient of thermal expansion than copper, which is the first material, and also have a larger Young's modulus than copper. Therefore, the non-solid-soluble copper-based alloy containing the second material made of chromium or cobalt is also non-solid-soluble containing the second material made of molybdenum or tungsten shown in FIGS. 2 to 5 and FIGS. 9 to 12. It is clear that the same tendency as that of the copper-based alloy is exhibited. Therefore, the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b) substantially made of a non-solid-soluble copper-based alloy containing the second material made of chromium or cobalt is the superconducting material 24. It is obvious that the main body portion 27 including can function as a reinforcing portion that mechanically reinforces. In addition, since chromium and cobalt have a larger thermal expansion coefficient than tungsten and molybdenum, a reinforcing portion (first reinforcing member) substantially composed of a non-solid-soluble copper-based alloy including the second material made of chromium or cobalt. It is also clear that the body 18a and the second reinforcement body 18b) can apply compressive stress to the superconductor 24.

  As described above, in the present embodiment, various requests required for the superconducting wire 20 (for example, a request for improving the allowable tensile stress of the superconducting wire 20 and improving the mechanical strength of the superconducting wire 20) are satisfied. In the non-solid-soluble copper-based alloy constituting the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b), for example, the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b). It can be obtained simply by changing the proportion of the first or second material. Therefore, in the present embodiment, it is possible to reduce time and effort for searching for a material suitable for the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b) of the superconducting wire 20, and the design of the superconducting wire 20 can be reduced. Can increase the degree of freedom.

  In the present embodiment, the second material contained in the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b) is the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body). It does not dissolve in the first material made of copper or copper-containing alloy contained in the body 18b). Therefore, similarly to the reinforcing portions (first reinforcing body 18a, second reinforcing body 18b) of the third embodiment, the reinforcing portions (for example, first reinforcing body 18a, second reinforcing body) of the present embodiment. The electrical resistivity of 18b) has a value between the electrical resistivity of the first material and the electrical resistivity of the second material.

In the present embodiment, the first material of the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b) is made of a copper-containing alloy such as copper or brass. As the second material of the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b), molybdenum, tungsten, chromium, and cobalt can be exemplified. Referring to Table 2, the electrical resistivity of the first material and the second material is 3.5 × 10 ⁻⁸ (Ωm) or less at the operating temperature of the superconducting wire 10 (for example, liquid nitrogen temperature of 77 K). It is. For this reason, in the present embodiment, the electrical resistivity of the reinforcing portion (the first reinforcing body 18a and the second reinforcing body 18b) is 3.5 × 10 ⁻⁸ (Ωm) or less.

  Referring to Table 2, at the operating temperature of superconducting wire 20 (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is the reinforcement of stainless steel (SUS) as a comparative example. Lower than 1/10 of the body's electrical resistivity. Therefore, the reinforcement part (for example, the 1st reinforcement body 18a, the 2nd reinforcement body 18b) of this Embodiment has an electrical resistivity lower than the reinforcement body of the stainless steel (SUS) which is a comparative example. According to the superconducting wire 20 of the present embodiment, the heat generation at the connecting portion between the normal conductor and the superconducting wire for introducing current from the normal conductor to the superconducting wire 20 and the connecting portion between the superconducting wires 20 is suppressed. Can do. Moreover, according to the superconducting wire 20 of the present embodiment, it is possible to prevent the superconducting wire 20 from being melted when quenching occurs in the superconducting material layer 4. Furthermore, according to the superconducting wire 20 of the present embodiment, the connection resistance between the plurality of superconducting wires 20 can be greatly reduced.

For example, the reinforcing body 18 in the superconducting wire 20 of the third mounting example of the present embodiment is 2.2 × 10 ⁻⁸ (Ωm) at the operating temperature of the superconducting wire 20 (for example, 77 K which is a liquid nitrogen temperature). Having an electrical resistivity of On the other hand, the reinforcing body in the superconducting wire of the third comparative example has an electrical resistivity of 3.5 × 10 ⁻⁷ (Ωm) at the operating temperature of the superconducting wire (for example, liquid nitrogen temperature of 77 K). . The superconducting wire 20 of the third mounting example of the present embodiment has an electrical resistivity of about 1/15 compared to the superconducting wire of the third comparative example. Therefore, in the superconducting wire 20 of the third mounting example of the present embodiment, it is possible to prevent the superconducting wire 20 from being melted when the superconducting material 24 is quenched. In the superconducting wire 20 of the third mounting example, the connection resistance between the plurality of superconducting wires 20 can be greatly reduced as compared with the superconducting wire of the third comparative example.

In the modification of the present embodiment, the reinforcing portion has only the first reinforcing body 18a, and the second reinforcing body 18b may not be provided. In other words, the reinforcing portion is provided on at least one of the first main surface 27 a and the second main surface 27 b of the main body portion 27. In this modification, when the warpage of the superconducting wire 20 becomes a problem, as described in the second embodiment, the thermal expansion coefficient of the reinforcing portion (first reinforcing body 18a) and the main body portion including the superconducting material 24. The ratio of the first material or the ratio of the second material included in the reinforcing portion (first reinforcing body 18a) is adjusted so that the difference from the coefficient of thermal expansion of 27 is 2 × 10 ⁻⁶ / K or less. May be.

(Embodiment 5)
With reference to FIG. 13, the connection structure 30 of the some superconducting wire which concerns on Embodiment 5 is demonstrated.

  In the connection structure 30 of the plurality of superconducting wires in the present embodiment, the respective reinforcing portions (for example, the first reinforcing body 18a, the first reinforcing body 18a, the first superconducting wire 20a, and the second superconducting wire 20b). Two reinforcing bodies 18b) are electrically and mechanically connected. Specifically, the second reinforcing body 18b of the first superconducting wire 20a and the first reinforcing body 18a of the second superconducting wire 20b are electrically and mechanically connected.

  As the plurality of superconducting wires (first superconducting wire 20a and second superconducting wire 20b), for example, superconducting wires 10b and 20 shown in FIGS. 7 and 8 can be used. In the present embodiment, the superconducting wire 20 shown in FIG. 8 is used as a plurality of superconducting wires (first superconducting wire 20a and second superconducting wire 20b).

  In the present embodiment, in the connecting portion 33, the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) of a plurality of superconducting wires (first superconducting wire 20a and second superconducting wire 20b). Are electrically and mechanically connected to each other. More specifically, the end of the first superconducting wire 20a and the end of the second superconducting wire 20b are stacked, and the end of the second reinforcing body 18b of the first superconducting wire 20a and the second The connection portion 33 is formed by fixing the end portion of the first reinforcing body 18a of the superconducting wire 20b using a fixing means (not shown) such as solder. It should be noted that, at positions different from the end of the first superconducting wire 20a and the end of the second superconducting wire 20b, reinforcing portions (for example, the first superconducting wire 20a and the second superconducting wire 20b) are provided. The first reinforcing body 18a and the second reinforcing body 18b) may be electrically and mechanically connected to each other.

With reference to Table 2, stainless steel has a high electrical resistivity at the operating temperature of the superconducting wire (for example, 77 K which is a liquid nitrogen temperature). The connection part of the comparative example in which a plurality of superconducting wires having reinforcing parts made of stainless steel are connected to each other has a plurality of high electrical resistances. Since the connecting portion has a high electrical resistance, heat is generated in the connecting portion, and the temperature in the vicinity of the connecting portion increases. Therefore, it becomes difficult to design a superconducting coil or a superconducting cable to which a plurality of superconducting wires are connected. In addition, there is a problem that the critical current I _c of the superconducting wire is reduced at the connection portion. Furthermore, when quenching occurs in the superconducting material included in the main body, the superconducting wire is likely to be blown at the connecting portion.

  By increasing the connecting portions of the plurality of superconducting wires along the longitudinal direction of the superconducting wires, an increase in electrical resistance at the connecting portions of the plurality of superconducting wires can be suppressed. However, if the connecting portions of the plurality of superconducting wires are lengthened along the longitudinal direction of the superconducting wires, the flexibility of the superconducting coil or superconducting cable to which the plurality of superconducting wires are connected decreases.

  On the other hand, in the connection structure 30 of the superconducting wire of the present embodiment, from a non-solid-soluble copper-based alloy composed of a first material composed of copper or a copper-containing alloy and a second material different from the first material. A plurality of superconducting wires (a first superconducting wire 20a and a second superconducting wire 20b) each having a substantially configured reinforcing portion (for example, a first reinforcing body 18a and a second reinforcing body 18b) are electrically connected to each other. And mechanically connected. The second material included in the reinforcing part (for example, the first reinforcing body 18a and the second reinforcing body 18b) is included in the reinforcing part (for example, the first reinforcing body 18a and the second reinforcing body 18b). It does not form a solid solution in the first material made of copper or a copper-containing alloy. Therefore, the electrical resistivity of the reinforcement part (for example, the 1st reinforcement body 18a, the 2nd reinforcement body 18b) of this Embodiment is the electrical resistivity of a 1st material, and the electrical resistivity of a 2nd material. With a value between

In this Embodiment, the 1st material of a reinforcement part (for example, 1st reinforcement body 18a, 2nd reinforcement body 18b) consists of copper or a copper containing alloy. As the second material of the reinforcing portion (for example, the first reinforcing body 18a and the second reinforcing body 18b), molybdenum, tungsten, chromium, and cobalt can be exemplified. With reference to Table 2, the electrical resistivity of the first material and the second material is 3.5 × 10 ⁻⁸ (Ωm) or less at the operating temperature of the superconducting wire 20 (for example, liquid nitrogen temperature of 77 K). It is. Therefore, in the present embodiment, the electrical resistivity of the reinforcing portions (for example, the first reinforcing body 18a and the second reinforcing body 18b) is 3.5 × 10 ⁻⁸ (Ωm) or less.

  Referring to Table 2, at the operating temperature of superconducting wire 20 (for example, 77 K which is a liquid nitrogen temperature), the electrical resistivity of the first material and the second material is the reinforcement of stainless steel (SUS) as a comparative example. Lower than 1/10 of the body's electrical resistivity. Therefore, the reinforcement part (1st reinforcement body 18a and 2nd reinforcement body 18b) of this Embodiment has an electrical resistivity lower than the reinforcement body of the stainless steel (SUS) which is a comparative example.

In the present embodiment, at the connection portion 33 of the plurality of superconducting wires (the first superconducting wire 20a and the second superconducting wire 20b), a reinforcing portion (for example, the first reinforcing body 18a, The two reinforcing bodies 18b) are electrically and mechanically connected to each other to form a superconducting wire connecting structure 30. Therefore, a superconducting wire connection structure 30 having a low connection resistance between the plurality of superconducting wires (first superconducting wire 20a and second superconducting wire 20b) can be obtained. Heat generated in the connection structure 30 of the superconducting wire can be reduced, and an increase in temperature can be suppressed in the connection structure 30 of the superconducting wire. As a result, the cooling design of the superconducting coil and the superconducting cable to which a plurality of superconducting wires are connected becomes easy. Further, the connecting portion 33 of a plurality of superconducting wires (first superconducting wires 20a and the second superconducting wire 20b), connecting the superconducting wire critical current I _c of the superconducting wire 20 can be prevented from being lowered structure 30 can be provided.

  In the superconducting wire connection structure 30, the connection resistance between the plurality of superconducting wires (the first superconducting wire 20a and the second superconducting wire 20b) is low. Therefore, it is possible to shorten the length of the connection portion 33 of the plurality of superconducting wires (first superconducting wire 20a and second superconducting wire 20b) in the longitudinal direction of the superconducting wire. As a result, the flexibility of the superconducting coil or superconducting cable provided with the connection structure 30 to which a plurality of superconducting wires are connected can be improved. Furthermore, when quenching occurs in the superconducting material 24, it is possible to prevent the superconducting wire 20 from being melted at the connection portion 33 of the plurality of superconducting wires (the first superconducting wire 20a and the second superconducting wire 20b). A superconducting wire connecting structure 30 can be provided.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. For example, in the above embodiment, Young's modulus is used as an index indicating the magnitude of mechanical strength, but 0.2% proof stress, tensile strength, etc. may be used as an index indicating the magnitude of mechanical strength. . The scope of the present invention is shown not by the above-described embodiment but by the scope of claims, and is intended to include meanings equivalent to the scope of claims and all modifications within the scope.

1, 10, 10b, 20 Superconducting wire 2,12 Substrate 3 Intermediate layer 4 Superconducting material layer 5 Protective layer 7, 27 Body 7a, 27a First main surface 7b, 27b Second main surface 7c, 27c Side surface 8 Stable Layer 15 base layer 16 joint 18 reinforcement 18a first reinforcement 18b second reinforcement 20a first superconducting wire 20b second superconducting wire 24 superconducting material 26 sheath part 30 connection structure 33 connection part

Claims (13)

A main body including a superconducting material, and
A reinforcing portion for mechanically reinforcing the main body including the superconducting material portion ;
An alignment metal film formed on the surface of the reinforcing portion and containing nickel tungsten or copper ;
The main body portion further includes an intermediate layer, and the superconducting material portion is provided on the intermediate layer,
The intermediate layer of the main body is provided on the oriented metal film,
The reinforcing portion is a superconducting wire substantially composed of a powder metallurgy sintered body made of a first material made of copper or a copper-containing alloy and a second material different from the first material. A main body including a superconducting material, and
A reinforcing portion for mechanically reinforcing the main body including the superconducting material portion;
A joining portion for joining the reinforcing portion to the main body portion,
The reinforcing portion is a superconducting wire substantially composed of a powder metallurgy sintered body made of a first material made of copper or a copper-containing alloy and a second material different from the first material. The difference between any thermal expansion coefficient of the reinforcing portion of the thermal expansion coefficient and the thermal expansion coefficient of the main portion of the superconducting material section, 2.0 × or less 10 ^-6 / K, according to claim 1 or claim 2. The superconducting wire according to 2 . Further comprising a substrate for supporting the main body,
The superconducting wire according to claim 2 , wherein the reinforcing portion is provided on the main body portion opposite to the substrate. The difference between the thermal expansion coefficient of the reinforcing portion and the thermal expansion coefficient of the substrate, 2.0 × at 10 ^-6 / K or less, the superconducting wire according to claim 4. The superconducting wire according to claim 2 , wherein the reinforcing portion is provided on two main surfaces of the main body portion. The superconducting wire according to claim 2 , wherein the reinforcing portion is configured to apply a compressive stress to the main body portion including the superconducting material portion. The superconducting wire according to any one of claims 1 to 7 , wherein a Young's modulus of the reinforcing portion is 150 GPa or more. The superconducting wire according to any one of claims 1 to 8 , wherein the first material is made of at least one material selected from the group consisting of copper, brass, white copper, and bronze. The superconducting wire according to any one of claims 1 to 9 , wherein the second material has a Young's modulus greater than that of the first material. The second material is molybdenum, is composed of at least one element selected from tungsten emissions or Ranaru group, superconducting wire according to any one of claims 1 to 10. The superconducting wire according to any one of claims 1 to 11 , wherein an electrical resistivity of the reinforcing portion is 3.5 x ^10-8 (Ωm) or less at a liquid nitrogen temperature. A plurality of the superconducting wires according to claim 12 ,
A superconducting wire connection structure in which the reinforcing portions of the plurality of superconducting wires are electrically and mechanically connected to each other.

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