JP6471625B2 - Superconducting conductive element - Google Patents

Description

  The present invention relates to a superconducting conductive element using an oxide superconducting bulk material.

  Superconductors such as oxide superconducting bulk bodies can be used for current-carrying elements such as current leads, current limiters, and permanent current switches because current can flow with zero electrical resistance. An oxide superconducting bulk is a kind of ceramic that is a brittle material. Unlike a superconducting wire, an oxide superconducting bulk does not have a support such as a metal coating or a metal substrate. Therefore, the current-carrying element using the oxide superconducting bulk body is electrically connected to both ends of the oxide superconducting bulk body mainly with an oxide superconducting bulk body and solder as disclosed in Patent Document 1. Electrode terminals and a support bonded to the oxide superconducting bulk with a resin or the like.

In particular, an oxide superconducting bulk material in which RE ₂ BaCuO ₅ is dispersed in single crystal RE ₁ Ba ₂ Cu ₃ O _7-x (where RE is one or more elements selected from rare earth elements) The oxygen deficiency (x) is 0.2 or less) because the current per unit area (critical current density) that can flow with zero electrical resistance is large, so that the oxide superconducting bulk body for the same rated current capacity The cross-sectional area can be reduced. On the other hand, a small cross-sectional area means that the oxide superconducting bulk body is easily damaged when or after the energization element is assembled.

Therefore, when an oxide superconducting bulk body in which RE ₂ BaCuO ₅ is dispersed in single-crystal RE ₁ Ba ₂ Cu ₃ O _7-x is used as a current-carrying element, one oxide superconducting bulk body is used. Reinforced strongly by the support. For example, Non-Patent Document 1 describes that a strong element structure in which the entire element is reinforced by double fixing a FRP cover as a support by resin bonding and bolt fastening is described.

JP 2008-177245 A

Low Temperature Engineering, Society of Low Temperature Engineering and Superconductivity, Vol. 45, No. 1 (2010), p. 22

  However, a strong element structure can be realized by using a support for each oxide superconducting bulk body and fixing it double by resin bonding and bolt fastening. However, when a plurality of superconducting elements are used, There is a problem that the volume occupied by the element is bulky.

  Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to provide a superconducting conductive element having a compact and strong element structure using a plurality of oxide superconducting bulk bodies. The purpose is to.

Superconducting conductive elements using the superconducting bulk material of the present invention are as follows.
(1)
A superconducting conductive element using an oxide superconducting bulk material in which RE ₂ BaCuO ₅ is dispersed in single-crystal RE ₁ Ba ₂ Cu ₃ O _7-x ,
A plate-like, rod-like or I-shaped oxide superconducting bulk body;
An electrode terminal having an external connection part electrically connected to both ends of the oxide superconducting bulk body and electrically connected to the outside;
It is arranged so as to cover at least the connection part between the oxide superconducting bulk body and the electrode terminal, and is bonded to the oxide superconducting bulk body and the connection part to reinforce the oxide superconducting bulk body and the connection part. A supporting body,
A superconducting conductive element unit composed of
A plurality of the superconducting conductive element units are arranged in parallel so that the supports are adjacent to each other,
A superconducting conductive element, wherein the superconducting conductive element is fixed by a fastening member disposed so as to penetrate the support and the electrode terminal in a parallel arrangement direction.
However, RE is one or more elements selected from rare earth elements, and the oxygen deficiency (x) is 0.2 or less.
(2)
The superconducting conductive element according to (1) above, wherein the external connection portions of the electrode terminals are arranged so as to be shifted from each other in the superconducting conductive element units adjacent in the parallel arrangement direction.
(3)
The external connection portions of the electrode terminals have a structure that is asymmetric with respect to the energization direction, and the superconducting conductive element units adjacent to each other in the parallel arrangement direction are opposite to each other with respect to the plane in the parallel arrangement direction. The superconducting conductive element according to (1) above, which is disposed.
(4)
The oxide superconducting bulk body is plate-shaped, and a plurality of the superconducting conductive element units are arranged in parallel in the thickness direction of the oxide superconducting bulk body, (1) to (3) above The superconducting conductive element according to any one of the above.

  As described above, according to the present invention, it is possible to provide a superconducting conductive element having a compact and strong element structure using a plurality of oxide superconducting bulk bodies.

It is a schematic side view which shows an example of the superconducting conductive element which concerns on the 1st Embodiment of this invention. It is a schematic sectional drawing which shows an example of the superconducting conductive element which concerns on the same embodiment. It is a schematic side view which shows the conventional superconducting conductive element. It is a schematic sectional drawing which shows the conventional superconducting conductive element. It is a conceptual diagram which shows another aspect of the superconducting bulk magnet which concerns on the 2nd Embodiment of this invention. It is a conceptual diagram which shows another aspect of the superconducting bulk magnet which concerns on the same embodiment. It is a conceptual diagram which shows another aspect of the superconducting bulk magnet which concerns on the same embodiment. It is a conceptual diagram which shows another aspect of the superconducting bulk magnet which concerns on the same embodiment. It is a conceptual diagram which shows another aspect of the superconducting bulk magnet which concerns on the same embodiment. It is a schematic structure sectional view of a superconducting conductive element. It is a perspective view which shows the example of a shape of the oxide superconducting bulk body used for a superconducting conductive element.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

<1. Schematic configuration>
As shown in FIG. 7, the superconducting conductive element 200 using the oxide superconducting bulk body includes oxide superconducting bulk bodies 211 and 213, electrode terminals 231 to 234, and supports 221 and 223. The oxide superconducting bulk bodies 211 and 213 are configured, for example, in a plate shape (210a), a rod shape (210b), or an I-shape (210c) as shown in FIG. The electrode terminals 231 to 234 are for connecting the superconducting conductive element 200 to the outside, and are electrically connected to both ends of the oxide superconducting bulk bodies 211 and 213. In order to facilitate connection to the external 2a to 2d, it is preferable to provide bolt fastening holes in the electrode terminals 231 to 234. In FIG. 7, a region P indicates an external connection portion between the electrode terminals 231 to 234 and the outsides 2 a to 2 d.

  As the material of the electrode terminals 231 to 234 used in the present embodiment, it is preferable to use a good electrical conductor such as copper, silver, or aluminum because the Joule heat generation of the electrode terminal itself can be reduced. Further, the surface of the electrode terminals 231 to 234 may be plated with tin, silver or the like. The oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234 can be electrically connected by using solder, silver paste, or the like. Since the Joule heat is generated at the connecting portion between the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234, the contact resistance is preferably low. In particular, it is preferable to use an oxide solder such as Cerasolzer (registered trademark) because the contact resistance between the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234 can be reduced. Furthermore, the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234 are formed by depositing silver on the surface of the oxide superconducting bulk bodies 211 and 213, at least on the portion connected to the electrode terminals 231 to 234, about 1 to 10 μm. This is preferable because the contact resistance can be further reduced.

  In addition, even if the cross-sectional areas of the oxide superconducting bulk bodies 211 and 213 are the same, in order to reduce the contact resistance with the electrode terminals 231 to 234, a plate shape or an I-shape with a large contact area with the electrode terminals 231 to 234 is a rod shape. More preferred.

  In addition, in FIG.8 (b), although cross-sectional shape has shown the rectangular rod shape, this invention is not limited to this example, For example, a cross-sectional shape may be another polygonal shape or circular shape.

  The connection between the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234 is achieved by providing grooves and holes in the electrode terminals 231 to 234, inserting the oxide superconducting bulk bodies 211 and 213 into the grooves and holes, It is preferable to connect the entire inserted portions of the superconducting bulk bodies 211 and 213 to the electrode terminals 231 to 234 by soldering or the like. The supports 221 and 223 are responsible for the mechanical strength of the connecting portion between the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234.

  The supports 221 and 223 are for preventing and reinforcing cracking of the oxide superconducting bulk bodies 211 and 213 which are ceramics of brittle materials. The oxide superconducting bulk bodies 211 and 213, the oxide superconducting bulk body 211, It fixes so that both the connection part of 213 and the electrode terminals 231-234 may be covered. As a method of fixing the supports 221, 223, it is preferable to fix the support bodies 221 and 223 in a double manner by resin bonding with adhesive resins 251 and 253 and fastening with bolts 241 and 243. Thereby, it can be set as a tough structure. The adhesive resins 251 and 253 are preferably those having sufficient adhesive strength at low temperatures, for example, epoxy resins. The fastening bolts 241 and 243 are preferably made of non-magnetic and high-strength stainless steel. In FIG. 7, a region Q indicates a connection portion between the oxide superconducting bulk bodies 211 and 213 and the electrode terminals 231 to 234.

  As the supports 221 and 223 used in this embodiment, fiber reinforced materials such as GFRP (glass fiber reinforced plastics) and CFRP (carbon fiber reinforced plastics), metal materials such as stainless steel, NiCr alloy, Ti alloy, alumina, A material having high strength and rigidity, such as a ceramic material such as silicon nitride, is preferable, and these materials may be used in combination.

The absolute value of the thermal expansion coefficient of the supports 221 and 223 is preferably larger than the absolute value of the thermal expansion coefficient of the oxide superconducting bulk bodies 211 and 213, but if it is too large, there is a possibility that an adverse effect is obtained. The difference in thermal expansion coefficient between the oxide superconducting bulk bodies 211 and 213 and the supports 221 and 223 is preferably in the range of 0.01% to 0.17%, and more preferably in the range of 0.04% to 0.10%. More preferred. For example, in the case of an oxide superconducting bulk body in which a RE ₂ BaCuO ₅ phase (211 phase) is finely dispersed in a single-crystal REBa ₂ Cu ₃ O _x phase (123 phase) produced by a melting method, from 300K to 77K The thermal expansion coefficient is 0.16% in absolute value, but the thermal expansion coefficient of the support at the same temperature is preferably in the range of 0.17% to 0.33%, more preferably 0.2% to 0%. A range of .26% is more preferred.

  Although the superconducting conductive element of the present embodiment has a structure in which a plurality of superconducting conductive element units are integrated, it is also possible to reduce the number of used supports by sharing a support between adjacent units. However, since the oxide superconducting bulk material is a brittle ceramic material and may break during energization element assembly, from the viewpoint of preventing cracking, each superconducting electroconductive element is sandwiched between the top and bottom one by one. Is preferred.

The superconducting bulk body used in the present embodiment is a non-crystal typified by a RE ₂ BaCuO ₅ phase (211 phase) having a diameter of 20 μm or less in a single-crystal RE ₁ Ba ₂ Cu ₃ O _7-x phase (123 phase). Any material may be used as long as it has a structure in which the superconducting phase is dispersed, and in particular, a material having a structure in which the non-superconducting phase is finely dispersed (hereinafter also referred to as “QMG material”) is desirable. Here, the term “single crystal” means that it is not a perfect single crystal, but also includes those having defects that may impede practical use, such as a low-angle grain boundary. RE in the 123 phase and the 211 phase is a rare earth element composed of Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu, and combinations thereof, and La, Nd, Sm, Eu, The 123 phase containing Gd deviates from the 1: 2: 3 stoichiometric composition, and Ba may be partially substituted at the RE site. In the 211 phase which is a non-superconducting phase, La and Nd are somewhat different from Y, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, and the ratio of metal elements is non-stoichiometric. It is known that it has a theoretical composition or a different crystal structure.

The fine dispersion of the 211 phase in the QMG material is extremely important from the viewpoint of improving the critical current density (J _c ). By adding a trace amount of at least one of Pt, Rh, or Ce, the grain growth of the 211 phase in the semi-molten state (a state composed of the 211 phase and the liquid phase) is suppressed, and as a result, the 211 phase in the material is reduced to about Refine to about 1 μm. The addition amount is 0.2 to 2.0 mass% for Pt, 0.01 to 0.5 mass% for Rh, and 0.5 to 2.0 mass for Ce from the viewpoint of the amount of the effect of miniaturization and the material cost. The mass% is desirable. The added Pt, Rh, and Ce partially dissolve in the 123 phase. In addition, elements that could not be dissolved form a composite oxide with Ba and Cu, and are scattered in the material. 211 phase ratio of 123 phase, from the viewpoint of _{J c} properties and mechanical strength, is desirably 5 to 35% by volume. Further, the material generally contains 5 to 20% by volume of voids (bubbles) of about 50 to 500 μm, and when Ag is added, 0 to about 1 to 500 μm of Ag or Ag compound is added depending on the amount added. More than 25% by volume.

  Further, the oxygen deficiency (x) of the superconducting bulk body after crystal growth is about 0.5 to 0.8, and shows a temperature change in resistivity like a semiconductor or an insulating material. This is annealed in an oxygen atmosphere at 350 ° C. to 600 ° C. for about 100 hours by each RE system, so that oxygen is taken into the superconducting bulk body and the oxygen deficiency (x) is 0.2 or less, which is a good superconductivity. Show properties. At this time, a twin structure is formed in the superconducting phase. However, including this point, it is referred to as a single crystal here.

  In order to use an oxide superconducting bulk body as a current-carrying element, the oxide superconducting bulk body after crystal growth is processed into a thin plate shape, I shape, rod shape, etc., and oxygen annealing of the oxide superconducting bulk body is performed after processing. become. When silver is deposited on the surface of the oxide superconducting bulk body, the oxygen adhesion is improved by performing oxygen annealing after the silver film is formed. As a result, the contact resistance between the oxide superconducting bulk body and the electrode terminal is reduced. Since it reduces, it is preferable.

<2. Configuration example of superconducting conductive element>
Embodiments of the present invention will be described below with reference to the drawings.

[2-1. First Embodiment]
1A and 1B are conceptual diagrams showing an example of the superconducting conductive element 100 according to the first embodiment of the present invention. In the example of FIGS. 1A and 1B, six superconducting conductive element units 102 using the oxide superconducting bulk body 110 are arranged in parallel so that the adjacent supports 120 are in contact with each other. Then, a bolt 142 that is a fastening member 140 is disposed so as to penetrate the connecting portion between the support 120 and the electrode terminal 130 in the parallel arrangement direction and is bolted by the nut 144, and the support 120 and the oxide superconducting bulk The body 110 and the electrode terminal 130 are bonded by resin.

The oxide superconducting bulk 110 has a non-superconducting phase represented by a RE ₂ BaCuO ₅ phase (211 phase) having a diameter of 20 μm or less in a single crystal RE ₁ Ba ₂ Cu ₃ O _7-x phase (123 phase). Has a dispersed structure and exhibits high critical current density characteristics.

  Both ends of the oxide superconducting bulk body 110 forming each superconducting conductive element unit 102 are electrically connected to electrode terminals 130 made of a good electrical conductor such as copper by solder or the like.

  Further, the six oxide superconducting bulk bodies 110 are integrally reinforced with a support body 120 made of a highly rigid material such as FRP (fiber reinforced plastic). The support 120 is bonded to the support 120, the oxide superconducting bulk 110, and the electrode terminal 130 by a resin having an adhesive force even at a low temperature, and further fixed in a double manner by fastening with a non-magnetic high-strength bolt. . Thereby, a strong structure is realized as the superconducting conductive element 100.

  Although not shown in FIGS. 1A and 1B, the superconducting conductive element 100 of the present embodiment is used by being connected to the outside at the electrode terminal portion by bolt fastening, solder connection, or the like.

  Here, for comparison with FIGS. 1A and 1B, FIGS. 2A and 2B are conceptual diagrams of conventional superconducting conductive elements. 2A and 2B show a state in which the same six superconducting elements as in FIGS. 1A and 1B are arranged. In each superconducting conductive element unit 10a, electrode terminals 13 are electrically connected to both ends of one oxide superconducting bulk body 11, and double reinforced by a support 12 by resin bonding and bolt fastening. In resin bonding, the support body 12, the oxide superconducting bulk body 11, and the electrode terminal 13 are bonded. Further, the oxide superconducting bulk body 11, the support body 12, and the electrode terminal 13 are fixed by a fastening member 14 such as a bolt penetrating them.

  Although not shown in FIGS. 2A and 2B, each superconducting conductive element unit 10a is used by being connected to the outside by bolt fastening, solder connection or the like at the electrode terminal portion, and by connecting each to the outside. The mounting position is fixed inside the apparatus.

  2A and 2B, the individual oxide superconducting bulk bodies 11 are individually reinforced. That is, since each of the support bodies 12 of the plurality of superconducting conductive element units 10a is individually bolted, the plurality of superconducting conductive element units are assumed to maintain the bolt fastening portion of the superconducting conductive element unit 10a. It is necessary to arrange 10a spatially apart from each other. Therefore, as shown in FIG. 2A and FIG. 2B, the volume that the superconducting conductive element unit 10a occupies spatially increases and becomes bulky, and the thickness of the superconducting conductive element unit 10a in the parallel arrangement direction increases.

  On the other hand, in FIGS. 1A and 1B having the structure of the present embodiment, the six oxide superconducting bulk bodies 110 are integrally reinforced by the support body 120, so that the superconducting conductive element units 102 are arranged in parallel. The direction thickness is thin. In other words, the superconducting conductive element 100 occupies a small volume, and a compact energizing element can be realized.

  In the case of the superconducting conductive element 100 having the structure as shown in FIGS. 1A and 1B, the thickness of the support 120 of the superconducting conductive element unit 102 per unit is determined as the individual support in the superconducting conductive element unit 10a of FIGS. 2A and 2B. Even if the thickness of the body 12 is the same, the mechanical strength of the entire energization element is greatly improved by fixing the entire support body integrally. On the contrary, even if the thickness of the support 120 of each superconducting conductive element unit 102 is smaller than the thickness of each support in the superconducting conductive element 100 of FIGS. 2A and 2B, the superconducting conductive element as a whole The strength of can be kept. That is, it is possible to make the thickness of FIG. 1A and FIG. 1B thinner than the case where the bolt fastening portion of the superconducting conductive element unit 10a of FIG. 2A and FIG.

  When the N superconducting conductive element units 102 are integrally supported, even if the thickness of each support 120 is reduced to 1/3 of the third root of N, the mechanical strength of the same level as the energization element is obtained. Have Therefore, according to this embodiment, it is possible to provide a superconducting conductive element 100 having a compact and strong element structure using two or more oxide superconducting bulk bodies 110. For example, when six oxide superconducting bulk bodies 110 are arranged in parallel, the mechanical strength can be secured even if the thickness is reduced to about 0.55 times.

[2-2. Second Embodiment]
Next, a superconducting conductive element according to a second embodiment of the present invention will be described with reference to FIGS. 3A to 6.

  FIG. 3A is a conceptual diagram showing one aspect of the superconducting conductive element 200A according to the present embodiment. As shown in FIG. 3A, superconducting conductive element 200 </ b> A includes supports 221 a and 223 a that support the oxide superconducting bulk body, and electrode terminals 231 to 234 having external connection portions 231 a to 234 a, respectively. Further, the supports 221a and 223a and the electrode terminals 231 to 234 of the superconducting conductive element 200A are fixed by a fastening member 240 such as a bolt. As shown in the upper side of FIG. 3A, in the superconducting conductive element 200A using an oxide superconducting bulk body, the entire energizing element and the electrode terminals are symmetrical with respect to the energizing direction from the viewpoint of ease of manufacture and arrangement. It has a structure.

  The superconducting conductive element 200A is formed by integrating a plurality of superconducting conductive element units 202A in an array of superconducting conductive element units 202A having a symmetric structure with respect to the energization direction as shown in the lower side of FIG. 3A. ing. At this time, when the superconducting conductive element 200A is viewed from the parallel arrangement direction, the external connection portions 231a to 234a to the outside of the electrode terminals 231 to 234 are substantially overlapped. Thereby, the occupied volume of the superconducting conductive element 200A is small, and a compact energizing element can be realized.

  Here, a compact superconducting conductive element formed using a plurality of superconducting conductive element units needs to be connected to the outside at a plurality of locations in a narrow space due to its compactness, but the electrode terminals interfere with each other. In addition, it is difficult to connect to the outside via the electrode terminals. Therefore, as shown in FIG. 3B, each superconducting conductive element unit 202B is configured such that the external connection portions 231b, 232b and 233b, 234b to the outside of the electrode terminals have an asymmetric structure with respect to the energization direction. Then, when the superconducting conductive element units 202B are arranged, the superconducting conductive elements are arranged such that the external connection portions 231b, 232b and 233b, 234b to the outside of the electrode terminals are arranged at least partially deviated from the parallel arrangement direction. The element 200B is configured. Thus, it is more preferable that the superconducting conductive element 200B is configured by integrating the plurality of superconducting conductive element units 202B so that the electrode terminals can be easily connected to the outside.

  4-6 is a conceptual diagram which shows another aspect of the superconducting conductive element which concerns on this embodiment. FIG. 4 shows an example in which the electrode terminals are arranged in a non-target manner with respect to the energization direction, as in FIG. In the superconducting conductive element 300 shown in FIG. 4, the electrode terminals 331 to 334 are provided obliquely with respect to the energization direction, so that the electrode terminals 331 and 333 and the electrode terminals 332 and 334 are completely separated when viewed from the parallel arrangement direction. It is configured not to overlap. This facilitates the connection between the electrode terminal and the outside. In addition, this invention is not limited to the example shown to FIG. 3B and FIG. 4, What is necessary is just an electrode terminal asymmetrical to an electricity supply direction.

  As another configuration for reducing the mutual interference between the electrode terminals, for example, as shown in FIG. 5, the electrode terminals 431 to 434 may have a vertically asymmetric structure with respect to the energization direction. 3B and 4, the electrode terminals are asymmetrical with respect to the surface on which the superconducting conductive element units are arranged with respect to the energization direction. However, in FIG. 5, the electrode terminals are asymmetric with respect to the energization direction. Two superconducting conductive element units 402a and 402b are integrated. In this way, the external connection portions of the electrode terminals 431 to 434 of the superconducting conductive element units 402a and 402b are arranged in parallel so as to be separated from each other, and the distance between the electrode terminals 431 and 433 and the electrode terminals 432 and 434 is increased, thereby Mutual interference between 431 to 434 can be reduced.

  As described above, the electrode terminal may have either a right asymmetrical structure or a vertically asymmetrical structure with respect to the energization direction as long as it has a structure that reduces mutual interference between electrode terminals adjacent in the parallel arrangement direction. Further, when three superconducting conductive element units 502 are integrated like the superconducting conductive element 500 shown in FIG. 6, the unit 502c having a structure in which the electrode terminals (535, 536) are symmetrical with respect to the energizing direction; The electrode terminals (531 to 534) are a combination of units 502a and 502b having a vertically asymmetric structure. As described above, the electrode terminals 531 to 536 may have a structure in which superconducting conductive element units in which the target terminals 531 to 536 have an asymmetric structure are combined as long as the mutual interference of the electrode terminals 531 to 536 is mitigated.

Example 1
A single crystal oxide superconducting bulk body containing 0.5% by mass of Pt and in which Dy ₂ BaCuO ₅ is finely dispersed in Dy ₁ Ba ₂ Cu ₃ O _y is mechanically processed to have a width of 3 mm and a thickness of A plate-like sample having a length of 0.8 mm and a length of 40 mm was produced. After forming a silver film on the surface of this plate-shaped sample at a thickness of about 1 μm and performing heat treatment in an oxygen stream at 400 ° C. for about 100 hours, copper electrode terminals having a shape as shown in FIG. They were connected and adhered by a GFRP support with resin. The support, the oxide superconducting bulk body, and the electrode terminal were bonded by resin bonding. Six of the same ones were produced, and the six were assembled together through a common bolt hole, and bolted using bolts and nuts having a bolt head thickness of 3 mm and a nut thickness of 3 mm. The thickness of the support made of GFRP is 1.5 mm, and the thickness of each superconducting conductive element unit in the parallel arrangement direction including the copper electrode terminal having a thickness of 3 mm is 6 mm. The thickness in the parallel arrangement direction was 42 mm (including the bolt fastening portion).

  On the other hand, as a comparative example, when the same superconducting conductive elements were individually manufactured one by one and arranged six, the thickness in the parallel arrangement direction was 92 mm. Thus, in this example, the volume occupied by the superconducting conductive element was reduced to about half.

  Furthermore, an energization test was performed on this superconducting conductive element in liquid nitrogen, but no change was observed in the energization characteristics even after repeated 10 times. This means that despite the fact that a superconducting conducting element was fabricated using a thin brittle oxide superconducting bulk material with a thickness of 0.8 mm, the mechanical handling during the energization test and the thermal shock during cooling This indicates that the oxide superconducting bulk material has not deteriorated. That is, it was found that the superconducting conductive element having this structure has a tough structure.

  From this result, it can be seen that the present invention can provide a compact superconducting conductive element using a plurality of oxide superconducting bulk bodies.

(Example 2)
A single crystal oxide superconducting bulk body containing ₁ % by mass of CeO ₂ and 10% by mass of Ag and having Gd ₂ BaCuO ₅ finely dispersed in Gd ₁ Ba ₂ Cu ₃ O _y is subjected to mechanical processing, As shown in FIG. 8 (c), an I-shaped sample having a width of 4 mm, a thickness of 4 mm, and a length of 58 mm was manufactured. After forming a silver film on the surface of this I-shaped sample with a thickness of about 2 μm and heat-treating at 400 ° C. for about 100 hours in an oxygen stream, copper electrode terminals are connected to both ends with an oxide solder, and resin is used. It adhered with the support body made from GFRP. The copper electrode terminal had an asymmetric structure with respect to the energization direction as shown in FIG. 3B. Two similar ones were produced, overlapped so that the asymmetric electrode terminals were in the opposite direction, and bolted together using a common bolt hole. The thickness of the GFRP support was 4 mm, but only the thickness of the surface where the two supports contacted was reduced to 2 mm. As a result, the thickness per one in the parallel arrangement direction including the copper electrode terminals was 14 mm, and the thickness in the parallel arrangement direction in the entire superconducting conductive element assembled into two pieces was 36 mm (including the bolt fastening portion). .

  On the other hand, as a comparative example, except that the thickness of any surface of the GFRP support is 4 mm, when the same superconducting conductive elements are individually manufactured one by one and arranged in two, the thickness in the parallel arrangement direction Was 52 mm. In this example, the volume occupied by the superconducting conductive element was reduced by about 30%. Furthermore, it was confirmed that the external connection portion of the electrode terminal with the outside has an asymmetric structure with respect to the energization direction and is arranged in the reverse direction, thereby facilitating connection with the outside.

  Further, the current conduction test was performed on the superconducting conductive element in liquid nitrogen, but no change was observed in the current conduction characteristics even when repeated 20 times. This is because the oxide superconducting bulk body deteriorates due to mechanical handling during the energization test and thermal shock during cooling, even though the superconducting conductive element was fabricated using the oxide superconducting bulk body made of brittle material. Indicates that it has not. That is, it was found that the superconducting conductive element having this structure has a tough structure.

  From this result, it can be seen that the present invention can provide a compact superconducting conductive element using a plurality of oxide superconducting bulk bodies.

  The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited to such examples. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Superconducting conductive element 102 Superconducting conductive element unit 110 Oxide superconducting bulk body 120 Support body 130 Electrode terminal 140 Fastening member 251, 253 Adhesive resin

Claims (4)

A superconducting conductive element using an oxide superconducting bulk material in which RE ₂ BaCuO ₅ is dispersed in single-crystal RE ₁ Ba ₂ Cu ₃ O _7-x ,
A plate-like, rod-like or I-shaped oxide superconducting bulk body;
An electrode terminal having an external connection part electrically connected to both ends of the oxide superconducting bulk body and electrically connected to the outside;
It is arranged so as to cover at least the connection part between the oxide superconducting bulk body and the electrode terminal, and is bonded to the oxide superconducting bulk body and the connection part to reinforce the oxide superconducting bulk body and the connection part. A supporting body,
A superconducting conductive element unit composed of
A plurality of the superconducting conductive element units are arranged in parallel so that the supports are in contact with each other,
A superconducting conductive element, wherein the superconducting conductive element is fixed by a fastening member disposed so as to penetrate the support and the electrode terminal in a parallel arrangement direction.
However, RE is one or more elements selected from rare earth elements, and the oxygen deficiency (x) is 0.2 or less.   2. The superconducting conductive element according to claim 1, wherein the external connection portions of the electrode terminals are arranged so as to be shifted from each other in the superconducting conductive element units adjacent in the parallel arrangement direction.   The external connection portions of the electrode terminals have a structure that is asymmetric with respect to the energization direction, and the superconducting conductive element units adjacent to each other in the parallel arrangement direction are opposite to each other with respect to the plane in the parallel arrangement direction. The superconducting conductive element according to claim 1, wherein the superconducting conductive element is disposed. The oxide superconducting bulk body is plate-shaped, and a plurality of the superconducting conductive element units are arranged in parallel in the thickness direction of the oxide superconducting bulk body. The superconducting conductive element according to Item 1.

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