JP2021054688A - Oxide superconductive bulk conductor and electrification element - Google Patents

Abstract

To provide an oxide superconductive bulk conductor that is superior in heat-resistant cycle property for suppressing warpage and peeling breakage against heat cycles, and also has a bypass function for current inside, and an electrification element that uses the oxide superconductive bulk conductor, according to the present invention.SOLUTION: An oxide superconductive bulk conductor according to the present invention has such a structure that an RE2BaCuO5 phase represented by RE2BaCuO5 composition formula is dispersed in an RE1Ba2Cu3Oy phase represented by composition formula RE1Ba2Cu3Oy and having a uniform crystal orientation, and also comprises two oxide superconductive bulk bodies which are plate-like, and a reinforcement member which is made of titanium or titanium alloy and plate-like, the oxide superconductive bulk bodies being fixed one over the other on at least two surfaces of the reinforcement member along a length direction of the reinforcement member.SELECTED DRAWING: Figure 1

Description

The present invention relates to an oxide superconducting bulk conductor using an oxide superconducting bulk body and an energizing element using the oxide superconducting bulk conductor.

Currently, copper is most often used as a conductor for conducting electricity. This is because the specific resistance at room temperature is about the same as that of silver, which is lower than that of other substances, and is relatively inexpensive. As a method of lowering the specific resistance of the conductor, there is a method of cooling the conductor. In the case of copper, when cooled to the liquid nitrogen temperature (77K), the specific resistance ^{becomes about 2.5 × 10 -9} Ωm, which is about 1/7 of the specific resistance at room temperature. The form of copper as a conductor includes a linear or tape-shaped wire rod and a plate-shaped or rod-shaped bus bar (conductor rod). Copper wire rods are used for cables, coils of electromagnets, field windings of synchronous motors, and the like. On the other hand, copper busbars are used for branch conductors of switchboards and control panels, conductors of induction motors, and the like. Copper busbars are often more efficient than copper wires as conductors for large currents.

Although the superconducting material needs to be cooled to a critical temperature of T _c or less, it has almost zero electrical resistance and is an ideal conductor. Metallic superconducting materials have a _{low critical temperature T c} and have not been widely used due to the need for cooling to extremely low temperatures. Therefore, when an _{oxide superconducting material having a critical temperature T c} as high as a liquid nitrogen temperature or higher and a relatively small cooling burden is put into practical use, it is expected that the oxide superconducting material will become widespread. The material form of the oxide superconductor includes a wire rod and a lumpy bulk body. The oxide superconducting wire can be applied to the application field in which the copper wire is used. On the other hand, if a plate-shaped conductor is cut out from an oxide superconducting bulk material, it can be applied to an application field in which a copper bus bar is used. Here, a conductor using an oxide superconducting bulk body cut out in a plate shape from an oxide superconducting bulk material will be referred to as an oxide superconducting bulk conductor. Furthermore, oxide superconducting bulk conductors include not only branch conductors for switchboards and control boards that use copper busbars, and conductors for induction motors, but also current leads and permanent current switches by attaching electrode terminals for external connection at both ends. It can also be applied to current-carrying elements such as.

As the oxide superconducting bulk material used for the oxide superconducting bulk conductor, a superconducting bulk material _{having a high critical temperature T c and} being able to pass a large current, that is, a superconducting bulk material having a high _{critical current density J c is desirable.} RE-Ba-Cu-O-based oxide superconductor (RE is one or 2 selected from the group consisting of Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu. _{The critical temperature T c} of (elements above the species) is as high as about 90 K. However, the bulk material of the RE-Ba-Cu-O oxide superconductor produced by the sintering method, which is a general method for producing oxides, is a polycrystalline superconducting bulk material composed of a large number of crystal grains. .. When the oxide superconducting bulk material is polycrystalline, a large number of grain boundaries existing inside obstruct the superconducting flow, so the critical current density J _c is 1.0 × 10 ³ A / cm ² or less at 77 K. Is a low value.

To improve the critical current density J _c, for example, as disclosed in Patent Document 1 below, it is melted crystal growth processes have been developed. By applying such a molten crystal growth process, RE _{is contained in RE 1} Ba ₂ Cu _{3 Oy (y in the} formula satisfies 6.8 ≦ y ≦ 7.1) in which the crystal orientations are aligned. ₂ It is possible to obtain an oxide superconducting bulk material having a structure in which BaCuO _{5 is finely dispersed. The RE 2} BaCuO ₅ phase finely dispersed inside has a function of pinning the magnetic field lines. Such an oxide superconducting bulk material exhibits a high characteristic even in a magnetic _{field having a critical current density J c} of 1.0 × 10 ⁴ A / cm ² or more in a magnetic field of 1 T having a temperature of 77 K. Here, "the crystal orientations are aligned" is synonymous with the fact that the crystal is a single crystal that does not contain a large tilt angle grain boundary inside.

By cutting out a bulk body in the form of a plate from an oxide superconducting bulk material, it is possible to manufacture a conductor such as a copper busbar. However, the oxide superconducting material is a brittle material, and the oxide superconducting bulk body cut out in an elongated shape has a problem that it is easily damaged as it is, and some kind of reinforcement is required for practical use. Causes of damage include external force during conductor handling and thermal stress during cooling. If the cause of the breakage is only the external force when handling the conductor, the strength can be increased by attaching a highly rigid reinforcing member to the oxide superconducting bulk body. However, since superconductors are used after being cooled, durability against thermal stress during cooling is also important. For example, Patent Document 2 below discloses that stainless steel, manganese steel, glass fiber reinforced plastic (GFRP) and the like are exemplified as conventional reinforcing bodies, and then titanium or a titanium alloy is used as the reinforcing body. .. In the current lead illustrated in Patent Document 2, the oxide superconducting bulk body is housed in the tubular reinforcing body, and the end portion is fixed to the electrode terminal. The reason why titanium and titanium alloys were selected as reinforcements is that the heat shrinkage of titanium and titanium alloys is higher than that of stainless steel, GFRP, or copper, which is a conventional conductor material, in the heat shrinkage of oxide superconducting bulk bodies. Because it is close, it is strong against the heat cycle.

Japanese Unexamined Patent Publication No. 2-153803 Japanese Unexamined Patent Publication No. 9-306721

As described above, it is possible to manufacture a conductor such as a copper busbar by cutting out a bulk body from an oxide superconducting bulk material into a plate shape, and by using titanium or a titanium alloy as a reinforcing member, a conductor resistant to a thermal cycle. It is also possible to. However, in the oxide superconducting bulk conductor using the oxide superconducting bulk body which is a brittle material, a current bypass (bypass function) is required in the unlikely event that the oxide superconducting bulk body is damaged, but the conventional oxide Since the superconducting bulk conductor did not have a bypass function, there was a problem that it could not be put into practical use. Of course, it is possible to add a bypass function by arranging an external conductive member in parallel with the oxide superconducting bulk conductor, but if the process of externally attaching the bypass function becomes unnecessary, the manufacturing process becomes simpler. Therefore, it has been required to have a bypass function inside the conductor.

As a structure having a bypass function inside the conductor, it is conceivable to form a reinforcing member of the oxide superconducting bulk body with a conductive material to provide the bypass function. If copper or the like, which is a conventional conductor material, is used as the reinforcing member, the bypass function may be sufficient, but there is a problem that the heat shrinkage rate of the oxide superconducting bulk body and copper is significantly different. Therefore, in the oxide superconducting bulk conductor using copper or the like, which is a conventional conductor material, as a reinforcing member, a member for preventing warpage or peeling breakage due to the difference in heat shrinkage between the oxide superconducting bulk body and copper is required. .. On the other hand, if titanium or a titanium alloy is used as a reinforcing member, there is a possibility that a peeling prevention member or the like becomes unnecessary, but the electrical resistivity of titanium or a titanium alloy is tens to hundreds of times as large as that of copper. So the bypass function was small and not enough.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is RE-Ba-Cu-O (RE is Y, La, Nd, Sm, Eu, Gd, Dy, An oxide superconducting bulk conductor using a rare earth-based oxide superconducting bulk body containing a composition of one or more elements selected from the group consisting of Ho, Er, Tm, Yb and Lu) undergoes a thermal cycle. It is an object of the present invention to provide an oxide superconducting bulk conductor having an excellent heat-resistant cycle property that suppresses warpage and peeling breakage and having a current bypass function inside, and an energizing element using the oxide superconducting bulk conductor. To do.

The oxide superconducting bulk conductor of the present invention is as follows.
(1) RE in the composition formula _{RE 1 Ba 2 Cu 3 O y} ( formula, Y, La, Nd, Sm , selected Eu, Gd, Dy, Ho, Er, Tm, from the group consisting of Yb, and Lu It is one kind or two or more kinds of elements, and y is represented by 6.8 ≦ y ≦ 7.2), and in the RE ₁ Ba ₂ Cu ₃ O _y phase in which the crystal orientations are aligned, has a composition formula _RE 2 BaCuO ₅ phase represented by _RE 2 BaCuO ₅ are dispersed tissue, and at least two oxide superconducting bulk body is a plate-like, plate-like reinforcing member made of titanium or a titanium alloy An oxide superconducting bulk conductor, characterized in that the oxide superconducting bulk body is superposed and fixed on at least two surfaces of the reinforcing member in the longitudinal direction of the reinforcing member.
(2) The reinforcing member has protrusions in contact with the end faces of the oxide superconducting bulk body at at least either both ends in the longitudinal direction of the reinforcing member or both ends in the plate width direction of the reinforcing member. The oxide superconducting bulk conductor according to (1).
(3) Two of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member are mutually different from each other in the longitudinal direction via the reinforcing member. The oxide superconducting bulk conductor according to (1), which has wall portions extending so as to face each other.
(4) At least one of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member has wall portions extending toward the reinforcing member at both ends in the longitudinal direction thereof. The oxide superconducting bulk conductor according to (1).
(5) The oxide superconducting bulk conductor according to (3) or (4), wherein the wall portion is electrically connectable to an electrode terminal for external connection at its longitudinal end. ..
(6) The two oxide superconducting bulk bodies are fixed to each of the two paired surfaces of the reinforcing member in the longitudinal direction of the reinforcing member, (1) to The oxide superconducting bulk conductor according to any one of (5).
(7) The oxide superconducting bulk conductor according to any one of (1) to (6) and
Each of the oxide superconducting bulk bodies, which comprises an electrode terminal electrically connected to the oxide superconducting bulk conductor and is fixed to at least two surfaces of the reinforcing member, is formed in the longitudinal direction of the oxide superconducting bulk body. An energizing element, characterized in that it is electrically connected to the electrode terminals at both ends of the.
(8) The energizing element according to (7), wherein the exposed surface of the oxide superconducting bulk body is covered with a non-permeable sheet or tape.

According to the present invention, in an oxide superconducting bulk conductor using a rare earth-based oxide superconducting bulk body having a composition of RE-Ba-Cu-O, it has a heat-resistant cycle property that suppresses warpage and peeling breakage even when subjected to a heat cycle. It is possible to provide an oxide superconducting bulk conductor which is excellent and has a current bypass function inside, and an energizing element using the oxide superconducting bulk conductor.

It is a perspective view which shows an example of the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is sectional drawing which shows an example of the electric current element using the conventional oxide superconducting bulk conductor. It is a perspective view which shows an example of the conventional oxide superconducting bulk conductor. It is a conceptual diagram which shows another example of the oxide superconducting bulk conductor which concerns on one Embodiment of this invention. It is a partial side view which shows the example of the protrusion of the end part in the oxide superconducting bulk conductor which concerns on the same embodiment. It is a conceptual diagram which shows another example of the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows another example of the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows another example of the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows another example of the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows an example of the electric current element using the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows another example of the electric current element using the oxide superconducting bulk conductor which concerns on embodiment of this invention. It is a conceptual diagram which shows the mode of the oxide superconducting bulk conductor and the electric current element in the Example of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The ratio and dimensions of each component in the drawing do not represent the actual ratio and dimensions of each component. Further, in the present specification and the drawings, a plurality of components having substantially the same functional configuration may be distinguished by adding different alphabets after the same reference numerals. However, if it is not necessary to distinguish each of the plurality of components having substantially the same functional configuration, only the same reference numerals are given.

<Overview of superconducting bulk body>
The oxide superconducting bulk body having the same crystal orientation (hereinafter, the oxide superconducting bulk body having the same crystal orientation is also simply referred to as “superconducting bulk body”) used in the present embodiment is RE-Ba-Cu-O based oxidation. It is a superconductor. More specifically, in the oxide superconducting bulk body having the same crystal orientation used in the present embodiment, the RE ₁ Ba ₂ Cu ₃ O _7-x phase (123 phase) in the _{form of a single crystal is contained in the RE 2} BaCuO ₅ phase (Phase 123). It has a structure in which non-superconducting phases typified by (211 phase) and the like are dispersed (hereinafter _{, RE 2} BaCuO ₅ phase in _{a monocrystalline RE 1} Ba ₂ Cu ₃ O _7-x phase (123 phase)). An oxide superconductor having a structure in which a non-superconducting phase represented by (211 phase) or the like is dispersed is also referred to as a “QMG material”). In particular, it is desirable that the oxide superconducting bulk body according to the present embodiment has a structure in which non-superconducting phases having a diameter of 20 μm or less are finely dispersed.

Here, "the crystal orientations are aligned" means that the crystal is a single crystal that does not contain the large tilt angle grain boundaries, which are the grain boundaries at which the superconducting current is significantly reduced. Further, the term "single crystal" does not mean only a complete single crystal, but also includes a single crystal having defects such as small tilt angle grain boundaries that may be practically used. The large tilt angle grain boundary means, for example, a grain boundary in which the angle of crystal orientation of adjacent regions across the grain boundary is larger than 15 °. Further, the small tilt angle grain boundary means, for example, a grain boundary in which the angle of the crystal orientation of the regions adjacent to each other across the grain boundary is 15 ° or less.

The constituent element RE in the 123 phase and 211 phase is selected from at least one selected from the group consisting of Y and rare earth elements. However, when Ce, Pr, Pm and Tb are contained as rare earth elements, they do not become superconductors, so Ce, Pr, Pm and Tb are excluded from the above RE. That is, the constituent elements RE in the 123 phase and 211 phase are selected from a rare earth element consisting of La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, and Lu, Y, and a combination of these elements. However, the 123 phase containing at least one of La, Nd, Sm, Eu, or Gd may deviate from the 1: 2: 3 stoichiometric composition, and the RE site may be partially replaced with Ba. is there. Also, in the non-superconducting phase 211, 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 the composition is theoretical and the crystal structure is different. Phases 123 and 211 include structures with compositions that deviate from the stoichiometric composition if the QMG material has superconducting properties. Further, as described later, the QMG material may contain Ag.

The above-mentioned substitution of Ba element tends to lower the critical temperature. Further, in the QMG material produced in an environment where the oxygen partial pressure is smaller, the substitution of the Ba element tends to be suppressed.

Such a single crystal oxide superconducting bulk body is not a sintering method which is a general manufacturing method for ceramics, but raises the molded body to a melting temperature higher than the sintering temperature as described in detail below. It is produced by a molten crystal growth method in which crystals are grown during slow cooling after being heated to a semi-molten state.

The 123 phase is formed by a peritectic reaction between the 211 phase and the liquid phase composed of a composite oxide of Ba and Cu as shown below.
211 phase + liquid phase (composite oxide of Ba and Cu) → 123 phase

The temperature at which the 123 phase is formed (Tf: 123 phase formation temperature) by this peritectic reaction tends to depend on the ionic radius of the constituent element RE, and Tf also decreases as the ionic radius of the RE element decreases. .. Further, Tf tends to decrease as the partial pressure of oxygen in the atmosphere decreases and the Ag content of the oxide superconducting bulk body increases.

A material in which the 211 phase is finely dispersed in the single crystal 123 phase is formed because the unreacted crystal grains of the 211 phase are left behind in the 123 phase when the 123 phase grows. That is, the bulk material is produced by the reaction shown below.
211 phase + liquid phase (composite oxide of Ba and Cu) → 123 phase + 211 phase

Fine dispersion of QMG 211 phase in the material, in view of the critical current density J _c improved, is extremely important. In addition to the above-mentioned constituent elements, the QMG material can also contain at least one of Pt, Rh or Ce in a trace amount. By containing at least one of Pt, Rh or Ce in a trace amount, the grain growth of the 211 phase in the semi-molten state (that is, the state consisting of the 211 phase and the liquid phase) is suppressed, and as a result, the QMG material The particle size of the 211 phase inside can be miniaturized to about 1 μm. The contents of these elements are Pt: 0.2 to 2.0% by mass and Rh: 0.01 to 0.5% by mass, respectively, from the viewpoint of the amount at which the miniaturization effect appears and the material cost. , Ce: preferably 0.5 to 2.0% by mass. More preferably, the content of Pt is 0.4 to 0.8% by mass, the content of Rh is 0.05 to 0.4% by mass, and the content of Ce is 0.1 to 0.3. It is mass%. When a plurality of Pt, Rh or Ce is used, the total amount of Pt, Rh or Ce contained is preferably 0.1 with respect to the total mass of the oxide superconducting bulk material (QMG material). It is by mass% or more and 2.0% by mass or less, and more preferably 0.2% by mass or more and 1.5% by mass or less. Pt, Rh and Ce contained in the QMG material are partially dissolved in the 123 phase. Further, of the Pt, Rh and Ce contained in the QMG material, the residue that could not be solid-solved forms a composite oxide with Ba and Cu and is scattered in the material. The QMG material has a four-fold rotational symmetry crystal structure as a whole bulk body.

Here, 211 phase ratio of 123 phase, from the viewpoint of properties and mechanical strength of the critical current density _{J c,} for example, it is desirable that 5 to 35% by volume. More preferably, it is 15% by volume or more and 30% by volume or less. Further, in the superconducting bulk body, voids (bubbles) of about 50 to 500 μm are generally present in an amount of about 5 to 20% by volume. Further, Ag can be further added to the superconducting bulk body in addition to the above-mentioned elements. When Ag is further added, the superconducting bulk body contains Ag or an Ag compound having a particle size of about 1 to 500 μm in an amount of more than 0% by volume and 25% by volume or less, depending on the amount of Ag added.

Further, the bulk body after crystal growth exhibits a temperature change in resistivity as a semiconductor or an insulating material when the oxygen deficiency amount (x) is about 0.5 to 0.8. By annealing such a bulk body after crystal growth at a temperature of 623K to 873K for about 100 hours in an oxygen atmosphere according to each constituent element RE, oxygen is taken into the superconducting bulk body and the amount of oxygen deficiency is reduced. (X) is 0.2 or less, that is, the oxygen amount y (= 7-x) is 6.8 or more, and exhibits good superconducting characteristics. At this time, a twin structure is formed in the superconducting phase. However, including such a twin structure, it is referred to as "single crystal" in the present specification.

In order to utilize such an oxide superconducting bulk body as an oxide superconducting bulk conductor, the oxide superconducting bulk body after crystal growth is processed into a predetermined shape such as a rod shape or a plate shape, and then the oxide as described above is used. It is required to perform oxygen annealing of the superconducting bulk body.

<Detailed description of the oxide superconducting bulk conductor according to this embodiment>
Hereinafter, the oxide superconducting bulk conductor according to the embodiment of the present invention will be described with reference to the drawings. It goes without saying that the oxide superconducting bulk conductor according to the present embodiment shown in the figure is merely an example, and the present invention is not limited to the embodiment shown in the figure.

FIG. 1 is a perspective view showing an example of an oxide superconducting bulk conductor according to the present embodiment. Oxide superconducting bulk conductor 10 according to this embodiment, RE in the composition formula _{RE 1 Ba 2 Cu 3 O y} ( formula, Y, La, Nd, Sm , Eu, Gd, Dy, Ho, Er, Tm , one or more elements selected from the group consisting of Yb, and Lu, represented by 6.8 ≦ y ≦ 7.2), the _RE 1 _Ba 2 _Cu 3 _{O y} phase with uniform crystal orientation oxide superconducting bulk body 110 plate-like having a _RE 2 BaCuO ₅ phase composition formula is represented by _RE 2 BaCuO ₅ are dispersed tissue, at least two surfaces of the plate-like reinforcing member 120 made of titanium or a titanium alloy (Excluding both end faces in the longitudinal direction of the reinforcing member 120), they are overlapped and fixedly arranged in the longitudinal direction (x-axis direction). In the following description, the direction in which the oxide superconducting bulk body 110 and the reinforcing member 120 are overlapped (z-axis direction) is referred to as the overlapping direction, and the direction perpendicular to the longitudinal direction in the plate surface is the width direction (y-axis). Direction). Further, the length in the stacking direction may be referred to as the thickness, and the length in the width direction may be referred to as the width.

If the oxide superconducting bulk body 110 used for the oxide superconducting bulk conductor 10 can be overlapped with the reinforcing member 120 made of plate-shaped titanium or a titanium alloy, its cross-sectional shape and longitudinal direction (connection to an external power source or electrode). There are no particular restrictions on the shape of the direction). In the oxide superconducting bulk body 110, the shape in the longitudinal direction thereof can be, for example, a straight line, a U shape, an S shape, or the like, as in the case of a copper bus bar, but it is easy to manufacture and overlaps with a reinforcing member. From the viewpoint of ease of alignment, a straight line is preferable. Further, if the cross-sectional shape perpendicular to the longitudinal direction is a polygonal shape, unlike the case of a circular shape or an elliptical shape, it has a flat portion and can be used because it can be overlapped with a plate-shaped reinforcing member. When the cross-sectional shape is square, it is easy to manufacture and process, and it is easy to superimpose it on the reinforcing member, which is preferable.

Further, the reinforcing member 120 made of titanium or a titanium alloy has a plate-like shape, and if it can be overlapped with the oxide superconducting bulk body 110, the cross-sectional shape and the shape in the longitudinal direction are not particularly limited. Therefore, the shape in the longitudinal direction (direction of connection to an external power source or electrode) needs to match the shape of the oxide superconducting bulk body 110, but the cross-sectional shape perpendicular to the longitudinal direction may be a polygonal shape. , It is preferable that the shape of the square shape is easy to overlap with the reinforcing member 120.

Further, if the oxide superconducting bulk body 110 is overlapped and fixed on at least two surfaces of the plate-shaped (polygonal cross section) reinforcing member 120, the object of the present invention can be achieved, but a large-capacity current can be achieved. From the viewpoint of passing through, it is preferable that the two surfaces having a large area (if the cross section has a rectangular shape, the two opposing surfaces on the long side) are overlapped and fixed.

Here, the thickness of the oxide superconducting bulk body 110 used for the oxide superconducting bulk conductor 10 is preferably 100 μm or more. As a conductor of the oxide superconducting material, there is also a superconducting tape wire rod in which the same material system is formed on a tape-shaped metal base material, but the thickness of the superconducting portion is about 1 μm. However, since the thickness of the superconducting portion of the superconducting tape wire is completely different from the thickness of the oxide superconducting bulk body 110, its properties and behavior are also significantly different. Further, it is difficult to cut out an oxide superconducting bulk material thinner than 100 μm to obtain an oxide superconducting bulk body 110. In the superconducting tape wire rod, the reason why the thickness of the superconducting portion is as thin as about 1 μm is that it is formed on the metal base material from the beginning of the wire rod manufacturing process, and the oxide superconducting bulk body 110 is also oxidized in that respect. It is different from the superconducting tape wire.

The oxide superconducting material is a brittle material, and in general, an oxide superconducting bulk body cut out from an oxide superconducting material is easily damaged as it is. However, for example, in the oxide superconducting bulk conductor 10 shown in FIG. 1, since titanium or a titanium alloy having high rigidity is used as the reinforcing member 120, the oxide superconducting bulk body 110 has a structure strong against external force. It has become. Moreover, brittle materials such as oxide superconducting materials have lower strength against tensile stress than compressive stress, and are likely to occur with long objects such as conductors, even against external forces acting in the direction of bending the conductor. The strength is low. However, by making the oxide superconducting bulk conductor 10 a conductor in which the oxide superconducting bulk body 110 is fixedly arranged on at least two surfaces of the reinforcing member 120, for example, as shown in FIG. 1, at least one of the surfaces thereof. The oxide superconducting bulk body 110 on the side has a structure that is not easily damaged. That is, when an external force acts in the direction of bending the oxide superconducting bulk conductor 10, stresses in opposite directions are generated in the oxide superconducting bulk bodies 110 on both sides of the reinforcing member 120, and the oxidation on the compressive stress side occurs. The superconducting bulk body 110 is particularly hard to be damaged. Further, the oxide superconducting bulk body 110 is cut out in the ab-axis direction of the crystal in which the longitudinal direction (x-axis direction) is easily energized. In the oxide superconducting bulk body 110 cut out so that the longitudinal direction is the ab axis, the heat shrinkage rate of the oxide superconducting bulk body 110 in the ab axis direction when cooled from room temperature of about 300 K to a liquid nitrogen temperature (77 K). Is 0.16%. On the other hand, the heat shrinkage when cooled from room temperature of about 300 K to liquid nitrogen temperature (77 K) is 0.15% for titanium, 0.15 to 0.17% for titanium alloy, 0.32% for copper, and stainless steel. It is 0.30% for steel and 0.26% for GFRP (fiber direction). Therefore, by using titanium or a titanium alloy having a thermal shrinkage ratio close to that of the oxide superconducting bulk body 110 as the reinforcing member 120, the thermal stress due to the difference in thermal shrinkage ratio during cooling is reduced, and the structure is strong against the thermal cycle. .. Further, by using the oxide superconducting bulk conductor 10 as a conductor in which the oxide superconducting bulk body 110 is fixedly arranged on at least two surfaces of the reinforcing member 120, even if the oxide superconducting bulk body 110 on one side is damaged by any chance. The oxide superconducting bulk body 110 on the opposite side functions as a current bypass (bypass function).

The oxide superconducting bulk body 110 and the reinforcing member 120 can be fixed by using an adhesive resin, solder, or silver paste. The electrical resistivity of titanium and titanium alloys is tens to hundreds of times higher than that of copper, so the bypass function is small, but by fixing with an electrically conductive material such as solder or silver paste, the oxide superconducting bulk on one side The current bypass function of the body 110 can be complemented. As a fixing method, an adhesive resin or solder is applied to both the adhesive surfaces of the oxide superconducting bulk body 110 and the reinforcing member 120, or to one of the adhesive surfaces of the oxide superconducting bulk body 110 and the reinforcing member 120. It can be fixed by applying and overlapping the adhesive surfaces. If necessary, the adhesiveness of the adhesive surface can be improved by applying a load by placing a weight or the like. When a room temperature curing type adhesive resin or silver paste is used, it can be fixed at room temperature, for example, 298K, but in the case of solder or heat curing type adhesive resin or silver paste, oxide superconductivity is carried out in the heating state. The adhesive surface of the bulk body 110 and the reinforcing member 120 are overlapped with each other. From the viewpoint of reinforcing the oxide superconducting bulk body 110, it is preferable to fix the oxide superconducting bulk body 110 to the reinforcing member 120 on the entire surface of the bonding surface, but when connecting a plurality of oxide superconducting bulk conductors 10 to each other, or Alternatively, when the oxide superconducting bulk conductor 10 is connected to another member, a portion that is not completely adhered may occur according to the shape of the connecting portion. In this way, when connecting a plurality of oxide superconducting bulk conductors 10 to each other, or when connecting the oxide superconducting bulk conductor 10 to another member (for example, an external electrode), solder or silver paste is used. By connecting, the contact electrical resistance of the connecting portion can be reduced.

Further, by providing a silver film (not shown) on the surface of the oxide superconducting bulk body 110, the contact electrical resistance is further reduced when the oxide superconducting bulk conductor 10 is electrically connected to other members. be able to. Although there is no restriction on the thickness of the reinforcing member 120, the thickness of the reinforcing member 120 is preferably 0.5 mm or more because the effect of reinforcement is reduced if the reinforcing member 120 is too thin. Further, if it is too thick, it becomes bulky as a conductor, so that the thickness of the reinforcing member 120 is preferably twice or less the thickness of the oxide superconducting bulk body 110.

Here, the current-carrying element 5 using the conventional oxide superconducting bulk conductor 50 and the conventional oxide superconducting bulk conductor 50A will be described with reference to FIGS. FIG. 2 is a cross-sectional view of a conventional oxide superconducting bulk conductor 50 and an energizing element 5 using the conventional oxide superconducting bulk conductor 50 shown for comparison. Further, FIG. 3 is a perspective view showing another conventional example, the oxide superconducting bulk conductor 50A. For example, in a conventional example such as Patent Document 2, titanium or a titanium alloy is used as a reinforcing member. In Patent Document 2, for example, as shown in FIG. 2, as an energizing element 5, an oxide superconducting bulk conductor 510 is housed inside a tubular reinforcing member 520 at both ends of an oxide superconducting bulk conductor 50. An example in which the electrode terminals 60 are connected and an example in which the oxide superconducting bulk body 510A is brought into close contact with one surface of the reinforcing member 520A as the oxide superconducting bulk conductor 50A are shown. However, although it is possible to make the oxide superconducting bulk conductor a conductor resistant to a thermal cycle by having a structure as shown in FIGS. 2 and 3, the oxide superconducting bulk conductor 50 and the oxide superconducting bulk conductor 50A Since there is no current bypass (bypass function) inside the conductor in the unlikely event that the oxide superconducting bulk conductors 510 and 510A are damaged, an external conductive member is arranged in parallel with the oxide superconducting bulk conductors 50 and 50A. It is necessary to add a bypass function by arranging it in. Therefore, a process of externally attaching the bypass function is required, which complicates the manufacturing process.

FIG. 4 is a conceptual diagram showing another example of the oxide superconducting bulk conductor according to the present embodiment. FIG. 4A is a perspective view of the oxide superconducting bulk conductor 10A, which is another example of the oxide superconducting bulk conductor according to the present embodiment, and FIG. 4B is a perspective view of the oxide superconducting bulk conductor 10A from the y direction. It is a side view as seen. The oxide superconducting bulk conductor 10A shown in FIG. 4 includes a reinforcing member 120 and an oxide superconducting bulk body 110 fixed to each of the two surfaces of the reinforcing member 120 in the longitudinal direction of the reinforcing member 120. A protrusion 121 is provided at the end of the reinforcing member 120 in the longitudinal direction. The length of the protrusion 121 in the stacking direction is longer than the length of the reinforcing member 120 in the stacking direction. By providing such a protrusion 121 at the end of the reinforcing member 120, in addition to making it very easy to fix the oxide superconducting bulk body 110 on at least two surfaces of the reinforcing member 120, the oxide It also helps to enhance the reinforcing effect of the end portion of the superconducting bulk conductor 10A. In FIG. 4, the reinforcing member 120 and the protrusion 121 at the end in the longitudinal direction are integrally formed from the beginning, or even if they are manufactured separately and finally bonded and integrated, the oxide superconducting bulk conductor 10A It has a similar effect in that it enhances the reinforcing effect of the end of the. However, in terms of the ease of arranging the oxide superconducting bulk body 110 on at least two surfaces of the reinforcing member 120, the reinforcing member 120 in the longitudinal direction and the protrusion 121 at the end may be integrated from the beginning. preferable.

FIG. 5 is a conceptual diagram showing an example of a protrusion at an end of an oxide superconducting bulk conductor according to an embodiment of the present invention. FIG. 5A shows an example in which the length of the protrusion 121 at the end of the reinforcing member 120 in the stacking direction is the same as the total thickness of the two oxide superconducting bulk bodies 110 and the reinforcing member 120. b) shows an example in which the length of the protrusion 121A at the end of the reinforcing member 120 in the stacking direction is shorter than the sum of the thickness of the two oxide superconducting bulk bodies 110 and the thickness of the reinforcing member 120, and FIG. Is an example in which the length of the protrusion 121B at the end of the reinforcing member 120 in the stacking direction is longer than the total thickness of the two oxide superconducting bulk bodies 110 and the reinforcing member 120. In the example of FIG. 5 (b), the effect is slightly small in that the reinforcing effect of the end portion of the oxide superconducting bulk conductor 10A is enhanced, and in the example of FIG. 5 (c), the oxide superconducting bulk conductor 10A is connected to the external connection portion. It is a little complicated to connect by soldering. Therefore, as in the example of FIG. 5A, the length in the stacking direction is the same as the sum of the thickness of the oxide superconducting bulk body 110 and the thickness of the reinforcing member 120 as in the protruding portion 121 at the end of the reinforcing member 120. Is preferable.

FIG. 6 is a conceptual diagram showing another example of the oxide superconducting bulk conductor according to the present embodiment. FIG. 6A is a perspective view of the oxide superconducting bulk conductor 10B, which is another example of the oxide superconducting bulk conductor according to the present embodiment, and FIG. 6B is a cross-sectional view taken along the line AA of FIG. 6A. (C) is a cross-sectional view taken along the line BB of (a). The oxide superconducting bulk conductor 10B shown in FIG. 6 is provided with protrusions 121 not only on the longitudinal end of the reinforcing member 120 but also on the longitudinal side surfaces (both ends in the width direction). By providing such protrusions 121 at both ends of the side surface of the reinforcing member 120, in addition to making it very easy to fix the oxide superconducting bulk body 110 on at least two surfaces of the reinforcing member 120. It also helps to enhance the reinforcing effect of the side surface portion of the oxide superconducting bulk conductor 10B. In this case, the oxide superconducting bulk body 110 has a rectangular cross-sectional shape in the longitudinal direction, and the reinforcing member 120 is overlapped and fixed on two flat portions forming a pair thereof. It is preferable because of its ease of use and ease of use.

As described above, as described with reference to FIGS. 4 to 6, the reinforcing member 120 has an end face of the oxide superconducting bulk body 110 at least at both ends in the longitudinal direction or both ends in the plate width direction thereof. It is preferable to have a protrusion 121 that comes into contact with.

FIG. 7 is a conceptual diagram showing another example of the oxide superconducting bulk conductor according to the present embodiment. FIG. 7A is a perspective view of the oxide superconducting bulk conductor 10C, which is another example of the oxide superconducting bulk conductor according to the present embodiment, and FIG. 7B is a perspective view of the oxide superconducting bulk conductor 10C from the y direction. It is a side view as seen. For example, as shown in FIG. 7, in the oxide superconducting bulk conductor 10C according to the present embodiment, the oxide superconducting bulk body 110 fixed to at least two surfaces of the reinforcing member 120 is located at one end different from each other in the longitudinal direction thereof. , It is preferable to have wall portions 112 extending so as to face each other via the reinforcing member 120. For example, in FIG. 7, the oxide superconducting bulk conductor 10C is a reinforcing member 120 and an oxide superconducting bulk body 110A fixed to each of the two surfaces of the reinforcing member 120 in the longitudinal direction of the reinforcing member 120. To be equipped. The oxide superconducting bulk body 110A is located at one end of the flat portion 111 having a substantially constant length in the stacking direction and one end in the longitudinal direction of the flat portion 111, and has a length in the stacking direction rather than a length in the stacking direction of the flat portion 111. Has a long wall portion 112. Each of the two oxide superconducting bulk bodies 110A has a wall portion 112 extending opposite to each other via a reinforcing member 120 at different ends thereof in the longitudinal direction. The stacking direction length of the wall portion 112 is equal to the total length of the stacking direction length of the flat portion 111 and the stacking direction length of the reinforcing member 120. By providing such a wall portion 112 at the longitudinal end of the oxide superconducting bulk body 110A, it becomes very easy to superimpose and fix the oxide superconducting bulk body 110A on the two surfaces of the reinforcing member 120. In addition, since the wall portion 112 of the oxide superconducting bulk body 110A is formed on the longitudinal end surface of the oxide superconducting bulk conductor 10C, it is connected to an external connection portion (connection terminal (not shown)) by soldering or the like. It will be easier to do. Further, the oxide superconducting bulk conductor 10C is also preferable in terms of increasing the contact area between the oxide superconducting bulk body 110A and the external connection portion.

FIG. 8 is a conceptual diagram showing another example of the oxide superconducting bulk conductor according to the present embodiment. FIG. 8A is a perspective view of the oxide superconducting bulk conductor 10D, which is another example of the oxide superconducting bulk conductor according to the present embodiment, and FIG. 8B is a perspective view of the oxide superconducting bulk conductor 10D from the y direction. It is a side view as seen. The oxide superconducting bulk conductor 10D shown in FIG. 8 is fixed to each of the two surfaces of the reinforcing member 120 and the reinforcing member 120 in the longitudinal direction of the reinforcing member 120, the oxide superconducting bulk bodies 110 and 110B. And. One oxide superconducting bulk body 110 has a flat portion 111, and the other oxide superconducting bulk body 110B has a flat portion 111 and wall portions 112 at both ends of the flat portion 111. The other oxide superconducting bulk body 110B has wall portions 112 at both ends in the longitudinal direction of the oxide superconducting bulk body 110B, so that the oxide superconducting bulk body 110B can be vertically fixedly arranged on the reinforcing member 120. In addition to facilitating, since the longitudinal end face of the oxide superconducting bulk conductor 10D is the wall portion 112 of the oxide superconducting bulk body 110B, the external connection portion (connection terminal (not shown)) and solder It becomes easy to connect by attaching. Further, the oxide superconducting bulk conductor 10D is also preferable in terms of increasing the contact area between the oxide superconducting bulk body 110B and the external connection portion.

Note that FIG. 8 illustrates an example in which one of the two oxide superconducting bulk bodies fixed to each of the two surfaces of the reinforcing member 120 in the longitudinal direction of the reinforcing member 120 has a wall portion 112. However, as shown in FIG. 9, any of the two oxide superconducting bulk bodies according to the present embodiment may have wall portions 112 at both ends of the flat portion 111. At this time, the sum of the stacking direction length of the wall portion 112 of one oxide superconducting bulk body 110C and the stacking direction length of the wall portion 112 of the other oxide superconducting bulk body is the flatness of the two oxide superconducting bulk bodies 110C. It is equal to the sum of the stacking direction length of the portion 111 and the stacking direction length of the reinforcing member 120.

As described with reference to FIGS. 8 and 9, in the oxide superconducting bulk conductor according to the present embodiment, at least one of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member has a length thereof. It is preferable to have wall portions extending toward the reinforcing member at both ends in the direction.

Further, in the embodiments of FIGS. 3 to 5, it does not matter whether or not the oxide superconducting bulk body 110 is fixed to the protrusions 121, 121A, 121B of the reinforcing member 120. Since the oxide superconducting bulk body 110 and the reinforcing member 120 are overlapped and fixed on two surfaces having a large area, they are sufficiently fixed even if they are not fixed by the protrusions 121, 121A, and 121B. Further, even if the protrusions 121, 121A, and 121B are fixed, the effect of the present invention is not diminished.

Further, in the embodiments of FIGS. 3 to 9, it does not matter whether the wall portion 112 and the reinforcing member 120 are fixed or not. Since the oxide superconducting bulk bodies 110A, 110B, 110C and the reinforcing member 120 are overlapped and fixed on two surfaces having a large area, it is sufficient even if the wall portion 112 and the reinforcing member 120 are not fixed. It is fixed. Further, even if the wall portion 112 and the reinforcing member 120 are fixed, the effect of the present invention is not diminished. Further, a silver film may be provided on the surface of the wall portion 112 on the reinforcing member 120 side.

Further, in the embodiments of FIGS. 1 and 3 to 9, the oxide superconducting bulk body 110 is fixed to the two paired surfaces of the reinforcing member 120 in the longitudinal direction of the reinforcing member 120, but is not necessarily fixed. It does not have to be fixed to the two paired surfaces, and may be fixed over the longitudinal direction of any two of the plurality of surfaces of the reinforcing member 120. If the reinforcing member 120 is fixed over the longitudinal direction of any two of the plurality of surfaces, the oxide superconducting bulk conductor has a heat-resistant cycle property that suppresses warpage and peeling breakage even when subjected to a thermal cycle. It is excellent and has a current bypass function inside.
Further, the cross-sectional shape of the reinforcing member 120 may be a triangular shape other than a quadrangular shape or a polygonal shape of a pentagon or more, and if at least two of them are fixed in the longitudinal direction, one surface is used. Compared to the case where it is fixed only to, it is excellent in heat-resistant cycle property that suppresses warpage and peeling damage even if it receives a heat cycle, and has an internal current bypass function. When the cross-sectional shape of the reinforcing member 120 is hexagonal, it has six planes in the longitudinal direction, but if the oxide superconducting bulk body 110 is superposed and fixed on every other three surfaces, the symmetry is enhanced. And more preferable.
However, as shown in FIGS. 3 to 9, the oxide superconducting bulk bodies 110, 110A, 110B, 110C are fixed to the two paired surfaces of the reinforcing member in the longitudinal direction of the reinforcing member 120. Is preferable. As a result, when an external force acts in the direction of bending the oxide superconducting bulk conductors 10, 10A, 10B, 10C, 10D, and 10E, the oxide superconducting bulk bodies 110, 110A, 110B, 110C on both sides of the reinforcing member 120 are sandwiched. Stresses in opposite directions are generated in the above, and the oxide superconducting bulk bodies 110, 110A, 110B, and 110C on the compressive stress side are particularly hard to be damaged. As a result, it becomes possible to maintain the function as a current bypass (bypass function) of the oxide superconducting bulk bodies 110, 110A, 110B, 110C.

FIG. 10 is a conceptual diagram showing an example of an energizing element using the oxide superconducting bulk conductor 10 according to the embodiment of the present invention. The energizing element 1 according to the present embodiment includes an oxide superconducting bulk conductor 10 and an electrode terminal 20 electrically connected to the oxide superconducting bulk conductor 10, and is fixed to at least two surfaces of the reinforcing member 120. Each of the oxide superconducting bulk bodies 110 is electrically connected to the electrode terminals 20 at both ends in the longitudinal direction of the oxide superconducting bulk body 110. FIG. 10A is a cross-sectional view of a cross section of the energizing element 1 using the oxide superconducting bulk conductor 10 cut in the y direction, and FIG. 10B is a top view of the energizing element 1 as viewed from the z direction. .. In the energizing element 1 shown in FIG. 10, electrode terminals 20 for external connection are attached to both ends of the oxide superconducting bulk conductor 10 in which the oxide superconducting bulk body 110 is fixedly arranged on each of the two surfaces of the reinforcing member 120. It is an energizing element. The electrode terminals 20 for external connection are connected to both of the two oxide superconducting bulk bodies 110 arranged so as to overlap each of the two surfaces of the reinforcing member 120 from the upper surface and the lower surface with solder or silver paste. There is. Since the reinforcing member 120 made of titanium or a titanium alloy is sandwiched between the oxide superconducting bulk bodies 110, the reinforcing member 120 has a bypass function. Therefore, the energizing element 1 in which the electrode terminals 20 are connected to both oxide superconducting bulk bodies 110 has an internal bypass function. Further, providing a silver film on the surface of the oxide superconducting bulk body 110 can reduce the contact electrical resistance when the oxide superconducting bulk conductor 10 and the electrode terminal 20 are electrically connected with solder or silver paste. It is preferable because it can be done. Needless to say, the energizing element according to the present embodiment is not limited to the energizing element shown in FIG. 10, and may use the above-mentioned oxide superconducting bulk conductor.

FIG. 11 is a conceptual diagram showing another example of an energizing element using the oxide superconducting bulk conductor according to the embodiment of the present invention. FIG. 11A is a side view of the energizing element 1A using the oxide superconducting bulk conductor 10 as viewed from the y direction, and FIG. 11B is a top view of the energizing element 1A as viewed from the z direction. The energizing element 1A shown in FIG. 11 has electrode terminals 20 for external connection at both ends in the longitudinal direction of the oxide superconducting bulk conductor 10 in which the oxide superconducting bulk body 110 is fixedly arranged on each of the two surfaces of the reinforcing member 120. In the current-carrying element 1 to which the above is attached, the exposed surface of the oxide superconducting bulk body 110 is covered with a waterproof material 30 such as a non-permeable sheet or tape. Only the surface of the oxide superconducting bulk body 110 may be coated with the non-permeable sheet or tape, but in FIG. 11, the exposed surface of the reinforcing member 120 is also coated from the viewpoint of simplicity of the coating operation. Similarly, a part of the electrode terminals 20 may be covered together. In the conventional current-carrying element using the oxide superconducting bulk conductor, the oxide superconducting bulk body is covered with a cover of a high-rigidity material such as GFRP from the outside, and the cover has a waterproof effect, but the cover also has a reinforcing effect. In order to have it, the thickness needs to be several mm or more. On the other hand, in the present invention, since the reinforcing member 120 made of titanium or a titanium alloy reinforces the oxide superconducting bulk body 110, the waterproof material 30 does not have to have a reinforcing effect, and only needs to have a waterproof effect. .. Therefore, as the waterproof material 30, for example, a material having a small thickness such as a non-permeable sheet or tape can be used, and the thickness of the waterproof material 40 can be reduced to 1 mm or less. From the viewpoint of simplicity of coating work, the thickness is more preferably 0.2 mm or less.

The various examples of the oxide superconducting bulk conductor and the current-carrying element using the oxide superconducting bulk conductor according to the embodiment of the present invention have been described above.

The oxide superconducting bulk conductor and its energizing element according to this embodiment are not limited to the examples shown in FIGS. 1, 4 to 11. That is, an oxide comprising an oxide superconducting bulk body and a reinforcing member made of titanium or a titanium alloy, and the oxide superconducting bulk body is laminated and fixedly arranged on at least two surfaces of the reinforcing member in the longitudinal direction. As long as the superconducting bulk conductor and the current-carrying element using the oxide superconducting bulk conductor are used, the mode of the oxide superconducting bulk conductor and the current-carrying element is not particularly limited.

Hereinafter, embodiments of the present invention will be specifically described with reference to examples. The examples shown below are merely examples of the present invention, and the present invention is not limited to the following examples.

(Example 1)
In this embodiment, the effectiveness of the oxide superconducting bulk conductor and the current-carrying element thereof according to the present embodiment will be described with reference to FIG. FIG. 12A is an oxide superconducting bulk conductor composed of only a plate-shaped oxide superconducting bulk body without a reinforcing member. FIG. 12B is an oxide superconducting bulk conductor in which a plate-shaped oxide superconducting bulk body is provided on one side of a plate-shaped titanium alloy reinforcing member, and FIG. 12C is a plate-shaped titanium alloy reinforcing member. It is an oxide superconducting bulk conductor provided with plate-shaped oxide superconducting bulk bodies on both sides of the member. FIG. 12D is an oxide superconducting bulk conductor in which plate-shaped oxide superconducting bulk bodies are provided on both sides of a plate-shaped copper reinforcing member. FIG. 12 (e) is an energizing element in which electrode terminals are attached to both ends of the oxide superconducting bulk conductor of FIG. 12 (b). FIG. 12 (f) is an energizing element in which electrode terminals are attached to both ends of the oxide superconducting bulk conductor of FIG. 12 (c). Here, the oxide superconducting bulk conductor shown in FIG. 12 (a) is sample A, the oxide superconducting bulk conductor shown in FIG. 12 (b) is sample B, and the oxide superconducting bulk conductor shown in FIG. 12 (c) is sample B. Is referred to as sample C, and the oxide superconducting bulk conductor shown in FIG. 12 (d) is referred to as sample D. Further, the energizing element using the oxide superconducting bulk conductor shown in FIG. 12 (e) is referred to as an energizing element E, and the energizing element using the oxide superconducting bulk conductor shown in FIG. 12 (f) is referred to as an energizing element F.

First, a method for producing the oxide superconducting bulk body, which is a base material for cutting out the rod-shaped oxide superconducting bulk body constituting Samples A to D, will be described. Commercially available powders of oxides of gadolinium (Gd), barium (Ba), and copper (Cu) having a purity of 99.9% by mass are used as Gd: Ba: Cu = 1.6: 2.3: 3. Weighed in a molar ratio of 3, and added 1% by mass of cerium oxide and 10% by mass of silver oxide in terms of silver to obtain a weighed powder. The weighed powder was sufficiently kneaded with (xxx) for 2 hours and then calcined in the air at 1173 K for 8 hours. Next, the calcined powder was formed into a disk shape using a mold. This molded body was heated to 1423 K to be in a molten state, held for 30 minutes, seeded in the middle of lowering the temperature, and slowly cooled in a temperature range of 1278 K to 1252 K for 100 hours to grow crystals, 60 mm in diameter and 60 mm in height. A 20 mm single crystal oxide superconducting bulk body was obtained. The resulting oxide superconducting bulk body is a _Gd 1 _Ba 2 _Cu 3 _{O y} phase with uniform crystal orientation, composition formula was _{tissue Gd} 2 BaCuO ₅ phase dispersed represented by _Gd 2 BaCuO ₅ .. Then, from this single crystal oxide superconducting bulk body having a diameter of 60 mm, an elongated rod-shaped sample having a length of 35 mm, a width of 2 mm, and a thickness of 0.8 mm is prepared so that the c-axis of the crystal is parallel to the side having a length of 0.8 mm. I cut it out like this. The elongated rod-shaped sample was formed by forming silver on the surface to a thickness of about 2 μm, and then heat-treated at 673 K for 100 hours in an oxygen stream.

For sample A, this elongated rod-shaped sample was used as an oxide superconducting bulk conductor. For sample B, a titanium alloy (Ti-6Al-4V) plate having a length of 35 mm, a width of 2 mm, and a thickness of 1 mm was used as a reinforcing member on one side of the oxide superconducting bulk body, and an epoxy resin (trade name: Stycast 2850FT) was used. ) Was applied to the entire surface. For sample C, an oxide superconducting bulk body was bonded with an epoxy resin on both sides of the same titanium alloy plate as the titanium alloy plate used for sample B. For Sample D, an oxygen-free copper plate of the same size as the titanium alloy plates used for Samples B and C was used as a reinforcing member, and an oxide superconducting bulk body was completely adhered to both surfaces thereof with an epoxy resin.

Five samples A to D prepared by the above method were prepared, and the cooling test from room temperature (298K) to liquid nitrogen temperature (77K) was repeated 10 times. For sample A, the oxide superconducting bulk body was damaged in 1 out of 5 samples during the handling of the repeated cooling test. Regarding sample D, due to the difference in heat shrinkage in the longitudinal direction between the oxide superconducting bulk body and the reinforcing member during cooling, all five pieces peeled between the oxide superconducting bulk body and the reinforcing member, and the degree of peeling as the cooling was repeated. Has grown. Furthermore, a part of the oxide superconducting bulk body near the portion peeled off to 2 out of 5 was damaged. With respect to Sample B and Sample C, warpage and peeling of the entire sample did not occur even after cooling, and there was no particular abnormality even after cooling 10 times. As a result of the above, it was confirmed that Sample B and Sample C are resistant to the thermal cycle.

Using Sample B and Sample C, which had no abnormality in the above-mentioned repeated cooling test, electrode terminals made of oxygen-free copper were soldered to 5 mm portions at both ends thereof, and are shown in FIGS. 12 (e) and 12 (f), respectively. The energizing element E and the energizing element F were manufactured. When the energizing element E and the energizing element F were energized in a state of being immersed in liquid nitrogen, both were able to energize 200 A or more. After the energizing element returned to room temperature, an external force was applied to the electrode terminal on the opposite side while the electrode terminal on one side of each energizing element was fixed, and a bending load was applied to the entire element. After that, when energized while being immersed in liquid nitrogen again, the energizing element E could not be energized, but the energizing element F could be energized at 200 A or more. As a result of the above, it was confirmed that the energizing element F has a bypass function by arranging the oxide superconducting bulk body on both sides of the reinforcing member.

Therefore, from this result, the oxide superconducting bulk conductor is configured such that the oxide superconducting bulk body is arranged on both sides in the longitudinal direction of the reinforcing member made of titanium or a titanium alloy, thereby forming RE-Ba-. In a rare earth-based oxide superconducting bulk conductor containing a composition of Cu—O, it is possible to provide an oxide superconducting bulk conductor having an internal bypass function and being resistant to a thermal cycle, and an energizing element thereof.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or modifications within the scope of the technical idea described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1,1A Current-carrying element 10, 10A, 10B, 10C, 10D, 10E Oxide superconducting bulk conductor 110, 110A, 110B, 110C Oxide superconducting bulk body 111 Flat part 112 Wall part 120 Reinforcing member 121, 121A, 121B Protrusion part 20 Electrode terminal 30 Waterproof material

Claims (8)

RE of composition formula _{RE 1 Ba 2 Cu 3 O y} ( in the formula, Y, La, Nd, Sm , Eu, Gd, Dy, Ho, Er, Tm, 1 kind selected from the group consisting of Yb, and Lu Alternatively, it is two or more kinds of elements, and y satisfies 6.8 ≦ y ≦ 7.2), and the composition formula is in _{the RE 1} Ba ₂ Cu ₃ O _{y phase in which the crystal orientations are aligned.} have a tissue _{which RE} 2 BaCuO ₅ phase represented by RE ₂ BaCuO ₅ are dispersed, and at least two oxide superconducting bulk body is a plate-like,
With a plate-shaped reinforcing member made of titanium or a titanium alloy,
An oxide superconducting bulk conductor, characterized in that the oxide superconducting bulk body is superposed and fixed on at least two surfaces of the reinforcing member in the longitudinal direction of the reinforcing member. The reinforcing member is characterized by having protrusions in contact with the end faces of the oxide superconducting bulk body at at least either both ends in the longitudinal direction of the reinforcing member or both ends in the plate width direction of the reinforcing member. The oxide superconducting bulk conductor according to claim 1. Two of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member face each other via the reinforcing member at different ends in the longitudinal direction thereof. The oxide superconducting bulk conductor according to claim 1, further comprising an extended wall portion. At least one of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member has wall portions extending toward the reinforcing member at both ends in the longitudinal direction thereof. The oxide superconducting bulk conductor according to claim 1. The oxide superconducting bulk conductor according to claim 3 or 4, wherein the wall portion is electrically connectable to an electrode terminal for external connection at an end portion in the longitudinal direction thereof. Any of claims 1 to 5, wherein the two oxide superconducting bulk bodies are fixed to each of the two paired surfaces of the reinforcing member in the longitudinal direction of the reinforcing member. The oxide superconducting bulk conductor according to item 1. The oxide superconducting bulk conductor according to any one of claims 1 to 6 and
An electrode terminal that is electrically connected to the oxide superconducting bulk conductor is provided.
Each of the oxide superconducting bulk bodies fixed to at least two surfaces of the reinforcing member is electrically connected to the electrode terminals at both ends in the longitudinal direction of the oxide superconducting bulk body. Energizing element. The current-carrying element according to claim 7, wherein the exposed surface of the oxide superconducting bulk body is covered with a non-permeable sheet or tape.

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