JP2018127381A - Method for producing superconductive bulk conjugate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a superconductive bulk conjugate excellent in a superconductivity characteristic even when a conjugation body and a conjugation layer are arranged horizontally.SOLUTION: A method includes: an arranging step of arranging a plurality of conjugation bodies for deviations of crystal orientation in conjugation bodies adjacent to each other to be 15° or lower, and a conjugation layer is arranged between the conjugation bodies adjacent to each other while bringing the conjugation layer into contact with the conjugation bodies; and a thermally treating step of heating the conjugation bodies and the conjugation layer at temperature lower than a melting point of the conjugation bodies but higher than a melting point of the conjugation layer to melt the conjugation layer, and thereafter conducting slow cooling to a temperature in which at least the conjugation layer is crystallized, to connect the conjugation bodies adjacent to each other via the conjugation layer. In the arranging step, the plurality of conjugation bodies and the conjugation layer are arranged horizontally while each of the conjugation bodies is supported by using at least one supporting member per conjugation body; and in the thermally treating step, the conjugation bodies are connected while keeping them arranged horizontally.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a superconducting bulk joined body in which superconducting bulk bodies are joined together.

  Bulk superconductors are called superconducting bulk bodies, which can achieve stable levitation without a very strong magnetic field source (superconducting bulk magnet) that exceeds conventional permanent magnets and complicated feedback control systems. Various applications are expected, such as contact bearings (superconducting bearings), current-carrying elements such as current leads that can carry a large current even in a magnetic field, and magnetic shields that can shield a strong magnetic field.

A superconducting bulk body used for such applications is preferably a superconducting bulk body having a high critical temperature (T _c ) and a high critical current density (J _c ) in a magnetic field. RE-Ba-Cu-O based oxide superconductor (RE is one or more elements selected from Y or a rare earth element) is the critical temperature T _c of but high as about 90K, the general preparation of oxides The bulk body produced by the sintering method is a polycrystalline superconducting bulk body composed of a large number of crystal grains. If superconductive bulk body is a polycrystalline, since a large number of grain boundaries existing therein inhibit superconducting current, the critical current density J _c is an 1.0 × 10 3 ^{A /} cm ² or less at 77K Is a low value.

To improve the critical current density J _c, for example, melting the crystal growth process, as disclosed in Patent Document 1 has been developed. By applying such a molten crystal growth process, RE ₂ BaCuO ₅ is incorporated into RE ₁ Ba ₂ Cu ₃ O _y (y is the amount of oxygen, 6.8 ≦ y ≦ 7.1) with the same crystal orientation. A superconducting bulk body having a finely dispersed structure can be obtained. Such superconducting bulk body, 77K, exhibits high characteristics even in a magnetic field of the critical current density _{J c} is 1.0 × ¹⁰ 4 A / cm ² or more at 1T. Here, the alignment of crystal orientations is synonymous with a single crystal shape that does not include a large-angle grain boundary inside.

  Such a superconducting bulk body having a uniform crystal orientation is manufactured by a melt crystal growth process, that is, by crystal growth using a seed crystal while slowly cooling. For this reason, when the size of the superconducting bulk body is increased, the manufacturing time becomes extremely long, and extra nucleation from other than the seed crystal occurs, so that it becomes easy to be polycrystallized, which makes it very difficult to manufacture. For this reason, the size that can be manufactured is substantially limited.

  In order to solve the problem of enlargement and lengthening of such superconducting bulk bodies, it is conceivable to join superconducting bulk bodies having a certain size and length. However, if the superconducting bulk bodies are simply joined together, the crystal orientations of the joining layers are shifted, or the superconducting current that can be generated by the polycrystallization of the joining layer portion that connects the superconducting bulk bodies is hindered. Due to the presence of crystal grain boundaries, the superconducting properties of the bonded body were lower than those of a single superconducting bulk body.

  For example, Patent Documents 2 and 3 disclose methods for solving such problems of the superconducting joint. Specifically, a joining body composed of a plurality of superconductors having a uniform crystal orientation has a melting temperature (peritectic temperature) lower than that of the joining body at the joining surface, and a superconductor having the same crystal orientation as the joining body. There is disclosed a superconducting bulk bonded body that is bonded via a bonding layer. In addition, the superconducting bulk bodies to be the bonding body are arranged with their crystal orientations aligned, and with the bonding layer sandwiched between them, the melting temperature is lower than the melting temperature of the bonding body and higher than the melting temperature of the bonding layer. By heating and then slowly cooling in a temperature range around the melting temperature of the bonding layer, the bonding layer portion in the molten state grows as a seed crystal with the bonded body at both ends, and finally the both ends It is disclosed that bonding can be performed in a state where all crystal orientations of the bonding body and the bonding layer are aligned.

  In this method, the melting temperature of the bonding layer needs to be lower than the melting temperature of the bonding body. Therefore, since the RE-Ba-Cu-O-based oxide superconductor has a property that the melting temperature differs depending on the element of the RE site, an element having a high melting temperature is selected as the bonding body, and the melting temperature is selected as the bonding layer. It has been proposed to select elements with low values.

  As another method, the RE-Ba-Cu-O-based oxide superconductor has a property that the melting temperature is lowered when silver is contained, so that it is proposed that the bonding layer contains silver or a silver compound. Has been.

Japanese Examined Patent Publication No. 4-40289 JP 6-40775 A JP-A-5-279028

  As described above, a manufacturing method in which heat treatment is performed after placing a joining body made of a superconductor having a melting point lower than that of a joining body in a joining body made of a plurality of superconducting bulk bodies with uniform crystal orientation is performed on both sides. This is an effective means that makes it possible to manufacture a superconducting bulk bonded body in which all the crystal orientations of the bonding body and bonding layer are aligned. When manufacturing a superconducting bulk joined body, it is necessary to install a superconducting bulk body which is a joining body and a superconductor which becomes a joining layer in an electric furnace. In that case, generally, for example, the joining body and the joining layer are directly installed on a heat insulating material such as alumina on the bottom of the electric furnace. Alternatively, a bonding main body and a bonding layer are arranged on a ceramic substrate such as alumina or magnesia outside the electric furnace, and the substrates are transported into the electric furnace and installed in the electric furnace.

  Conventionally, when manufacturing a superconducting bulk joined body, for example, as shown in FIG. 10A, a superconducting bulk body that is a joining body 92 and a superconductor that becomes a joining layer 93 are vertically stacked in an electric furnace. After placement, heat treatment for bonding was often performed. On the other hand, as shown in FIG. 10B, it is also conceivable to perform heat treatment for bonding after the bonding body 92 and the bonding layer 93 are arranged in the horizontal direction. When the vertical arrangement in which the bonding main body 92 and the bonding layer 93 are arranged in the vertical direction is compared with the horizontal arrangement in which the bonding main body 92 and the bonding layer 93 are arranged in the horizontal direction, the superconducting bulk bonded body 91 is formed using the short bonding main body 92. When manufacturing, there is no significant difference in workability between vertical and horizontal arrangements. However, when manufacturing a long superconducting bulk bonded body 1, the horizontal arrangement is more work than the poorly arranged vertical arrangement. Sex is much better.

  However, the conventional method for manufacturing a superconducting bulk bonded body has a problem that the superconducting characteristics in the horizontal arrangement in the horizontal direction are lower than in the vertical arrangement in which the bonding body and the bonding layer are arranged in the vertical direction. It was. In particular, the problem is that the superconducting properties of the bonding layer and its surroundings are degraded.

  In view of the above, an object of the present invention is to solve the above problems and to provide a method of manufacturing a superconducting bulk bonded body excellent in superconducting characteristics even when the bonding body and the bonding layer are arranged in the horizontal direction.

  As a result of earnest investigation by the inventor on the cause of deterioration in characteristics of the superconducting bulk joint manufactured in the lateral arrangement, the superconducting bulk joint manufactured in the horizontal arrangement is a superconducting bulk joint manufactured in the vertical arrangement. In comparison with the above, it has been found that impurities in alumina and magnesia, which are the materials of the heat insulating material and the substrate, are large in the bonding layer and its periphery, which causes the deterioration of the superconducting characteristics. In the superconducting bulk bonded body manufactured in the lateral arrangement, the bonding layer and the periphery thereof have a large amount of impurities. The bonding layer is in a semi-molten state in the heat treatment step for bonding, but the arrangement shown in FIG. Then, it is considered that the mixing of the impurities is accelerated because the bonding layer portion in a semi-molten state is in direct contact with the bottom surface of the electric furnace or the substrate.

  On the other hand, in the case of the vertical arrangement, the bonding layer portion that has become a semi-molten state does not directly touch the bottom surface of the electric furnace or the substrate. That is, when a superconducting bulk bonded body is manufactured in a horizontal arrangement, the contamination of impurities (contamination) from an alumina heat insulating material or an alumina substrate or a magnesia substrate in an electric furnace is larger than that in a vertical arrangement. It was found that the superconducting properties of the superconducting bulk joint were low because it was easily affected. In addition, in the case of manufacturing in either the vertical arrangement or the horizontal arrangement, although there are some impurities in the superconducting bulk bonded body, the maximum temperature in the heat treatment step is lower than the melting temperature of the bonded main body, Since the joint body is not in a semi-molten state, the amount of impurities greatly reduces the superconducting properties even in the part where the joint body is in direct contact with the alumina heat insulating material or alumina substrate or magnesia substrate in the electric furnace. It doesn't let you.

Based on the above-described points, a method for manufacturing a superconducting bulk joint using the superconducting bulk body of the present invention is as follows.
(1) A plurality of junction bodies formed of first oxide superconductors with aligned crystal orientations are arranged so that the deviation of the crystal orientations of the adjacent junction bodies from each other is within 15 °. A bonding layer formed by a second oxide superconductor having a material characteristic having a melting temperature lower than that of the first oxide superconductor is brought into contact with each other between the bonded main bodies. An arrangement step of arranging, melting the bonding layer by heating the plurality of bonding bodies and the bonding layer to a temperature lower than the melting temperature of the bonding body and higher than the melting temperature of the bonding layer; Then, the method of manufacturing a superconducting bulk joined body, comprising: annealing at least to a temperature at which the joining layer is crystallized, and joining the joining bodies adjacent to each other via the joining layer. Craft In the heat treatment step, the plurality of bonding bodies and the bonding layer are disposed in a horizontal direction while supporting each of the plurality of bonding bodies using at least one support member per bonding body. The bonding bodies adjacent to each other are bonded to each other through the bonding layer in a state in which the arrangement direction of the plurality of bonding main bodies supported by the support member and the bonding layer is maintained in the horizontal direction. A method of manufacturing a superconducting bulk bonded body.
(2) In the arrangement step, each of the plurality of bonded main bodies is supported using a plurality of the supporting members per one bonded main body. The method for producing a superconducting bulk bonded body according to (1) .
(3) The method for manufacturing a superconducting bulk bonded body according to (1) or (2), wherein the bonding body and the bonding layer are bonded with an organic adhesive or silver paste.
(4) The first oxide superconductor and the second oxide superconductor are RE ₁ Ba ₂ Cu ₃ O _y (RE is one or more selected from the group consisting of Y and rare earth elements) Any one of (1) to (3), wherein y is an oxygen amount and is an oxide superconductor in which RE ₂ BaCuO ₅ is dispersed in 6.8 ≦ y ≦ 7.1) 2. A method for producing a superconducting bulk joined body according to item 1.
(5) In any one of (1) to (4), the bonding body and the bonding layer contain 2% by mass to 30% by mass of silver in terms of metallic silver. Manufacturing method of superconducting bulk joined body described

  Here, the “superconducting bulk joined body” is one large superconducting bulk body or one long superconducting bulk body obtained by joining several superconducting bulk bodies (joining bodies).

  As described above, according to the present invention, it is possible to provide a method for manufacturing a superconducting bulk bonded body having excellent superconducting characteristics even when the bonding body and the bonding layer are arranged in the horizontal direction.

It is a conceptual diagram which shows an example of the manufacturing method of the superconducting bulk joined body in this embodiment. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a perspective view which shows the example of the shape of the support member which concerns on the embodiment, and installation. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a bottom view which shows the example of arrangement | positioning of the supporting member which concerns on the embodiment. It is a conceptual diagram which shows the manufacturing method of the superconducting bulk joined body which concerns on the modification of the embodiment. It is a conceptual diagram which shows the manufacturing method of the superconducting bulk joined body which concerns on the modification of the embodiment. It is a conceptual diagram for demonstrating the aspect of the joining main body and joining layer which comprise the superconducting bulk joined body based on one Example of the embodiment. It is a perspective view which shows the example of arrangement | positioning of each member in the manufacturing method of the superconducting bulk joined body based on one Example of the embodiment. 5 is a graph showing measurement results of a captured magnetic field distribution of sample A. It is a graph which shows the measurement result of capture magnetic field distribution of sample B. It is a perspective view which shows the example of arrangement | positioning of the supporting member in the manufacturing method of the superconducting bulk joined body based on one Example of the embodiment. It is a graph which shows the result of the magnetic field strength in the joining layer of each sample. It is a conceptual diagram which shows the example (vertical arrangement | positioning) of the arrangement | positioning of the joining main body and joining layer in the manufacturing method of the conventional superconducting bulk joined body. It is a conceptual diagram which shows the example (horizontal arrangement | positioning) of the arrangement | positioning of the joining main body and joining layer in the manufacturing method of the conventional superconducting bulk joined body.

  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.

An oxide superconducting bulk body with a uniform crystal orientation used in the present embodiment has 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). ), Etc., as long as it has a structure in which the non-superconducting phase is dispersed. In particular, a structure 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” includes not only a perfect single crystal but also a defect having a defect that may be practically used 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, and Lu, and combinations thereof. The 123 phase containing La, Nd, Sm, Eu, and 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. Such a single-crystal oxide superconducting bulk material is not a sintering method, which is a general method for producing ceramics, but is heated to a temperature higher than the melting temperature higher than the sintering temperature to make it a semi-molten state. Thereafter, it is manufactured by a melt crystal growth method in which crystals are grown during slow cooling.

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 Pt: 0.2 to 2.0% by mass, Rh: 0.01 to 0.5% by mass, Ce: 0.5 to 2.0 from the viewpoint of the amount at which the effect of miniaturization appears and the material cost. It is desirable that it is mass%. 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 properties and mechanical strength of the critical current density _{J c,} is preferably 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, for example, a superconducting bearing, the oxide superconducting bulk body after crystal growth is processed into a predetermined shape such as a disk shape, a square shape, a fan shape, a tile shape, etc. It is required to perform oxygen annealing of the superconducting bulk material.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the superconducting bulk body that becomes the bonding body 2 and the superconductor that becomes the bonding layer 3 after the heat treatment before the heat treatment step may also be referred to as the bonding body 2 and the bonding layer 3.

  FIG. 1 is a conceptual diagram showing an example of a method for manufacturing a superconducting bulk bonded body 1 in the present embodiment. The junction body 2 is composed of a superconducting bulk body of an oxide superconductor (corresponding to a first oxide superconductor) having a uniform crystal orientation. In FIG. 1, two bonding bodies 2 are arranged in a horizontal direction so that a deviation in crystal orientation between each other is within 15 °, and the melting temperature is lower than the bonding bodies 2 between adjacent bonding bodies 2. A superconductor of another oxide superconductor (corresponding to a second oxide superconductor) having material characteristics is arranged in contact with the bonding body 2. Such a superconductor is a portion where the oxide superconductor disposed between the bonding bodies 2 becomes the bonding layer 3 after the heat treatment.

  Further, in FIG. 1, in the arrangement step, the bonding body 2 and the bonding layer 3 are disposed in the horizontal direction in a state where the bonding body 2 is supported by the support member 5. In such a support state, the arrangement direction of the bonding body 2 and the bonding layer 3 is maintained in the horizontal direction, and the bottom surface in the electric furnace or the substrate on which the bonding body 2 and the bonding layer 3 are arranged (hereinafter collectively referred to as the substrate 4). The oxide superconductor to be the bonding layer 3 is not directly touched.

  In the state shown in FIG. 1, the oxide superconductor that is heated to a temperature lower than the melting temperature of the bonding body 2 and higher than the melting temperature of the bonding layer 3 is melted to become the bonding layer 3. By slowly cooling to a temperature at which the layer 3 crystallizes, the bonding layer 3 in the molten state grows as a seed crystal using the adjacent bonding body 2 as a seed crystal. Thereby, these can finally be joined in a state in which the deviation of the crystal orientation between the adjacent joining body 2 and the joining layer 3 is reduced. That is, the superconducting bulk bonded body 1 in which the adjacent bonded main bodies 2 are bonded to each other through the bonding layer 3 can be manufactured.

  In addition, by arranging adjacent bonding bodies 2 so that their crystal orientations are the same, the crystal orientation of the superconducting bulk bonded body 1 formed across the bonding layer 3 may be the same as the whole. it can.

  In FIG. 1, two joining bodies 2 are joined via a joining layer 3. In addition, the number of the joining main bodies 2 is not specifically limited, For example, you may join 3 or more joining main bodies 2 as needed. In addition, about the order which arrange | positions the joining main body 2 and the joining layer 3, for example, after joining two or more joining main bodies 2 initially, the joining layer 3 may be inserted among these, or the joining main body 2 may be inserted. These may be arranged while the bonding layers 3 are sequentially arranged.

  When the heat treatment process for joining the joining body 2 is performed in the state of being arranged as shown in FIG. 1, the following advantages are obtained. That is, since the bonding layer 3 that is in a semi-molten state during the heat treatment process does not directly touch the substrate 4, it is possible to suppress the mixing of impurities into the bonding layer 3 and its periphery.

  Furthermore, compared with the case of the horizontal arrangement of FIG. 10B of the conventional example, the bonding body 2 and the substrate 4 do not contact each other, and the bonding body 2 contacts only a few points with the support member 5. That is, the contact area between the bonding body 2 and the support member 5 is significantly smaller than the contact area between the bonding body 2 and the substrate 4. Accordingly, it is possible to further reduce the contamination of the junction body 2 during the heat treatment process.

  It should be noted that the contamination of the bonding layer 3 can be suppressed even in the case of the vertical arrangement shown in FIG. 10A of the conventional example. However, when manufacturing a long or large superconducting bulk bonded body 1, it is better in terms of workability to arrange the bonding body 2 and the bonding layer 3 in the horizontal direction than in the vertical direction. Yes. In particular, when a plurality of elongated joining bodies 2 are joined in the longitudinal direction, it is practically impossible to manufacture a long superconducting bulk joined body 1 in a longitudinal arrangement with a poor balance. The workability is much better.

  Here, it supplements about the crystal orientation of an oxide superconductor. The crystal structure of the oxide superconductor has a laminated structure. The stacking direction of the crystal structure is referred to as the c-axis direction of the crystal, and the directions perpendicular to the c-axis direction are referred to as the a-axis direction and the b-axis direction. Since the oxide superconductor has a twin structure in the plane formed by the a-axis and the b-axis, the a-axis direction and the b-axis direction cannot be distinguished from the whole superconducting bulk body. Therefore, in this specification, it is called an ab axis. A broken line 2a in FIG. 1 indicates a boundary between layers having a crystal structure.

  In the embodiment of the present invention, it is preferable that the crystal orientation deviation between the adjacent bonded bodies 2 is within 15 degrees in both the ab axis direction and the c axis direction. Further, the smaller the deviation of the crystal orientation between the adjacent bonding bodies 2 is, the smaller the decrease in the superconducting current is. Therefore, the deviation of the crystal orientation between the adjacent bonding bodies 2 is more preferably within 5 degrees. Since the sandwiched bonding layer 3 grows with the adjacent bonding body 2 as a seed crystal as described above, a portion having two crystal orientations is formed with the substantially central portion of the bonding layer 3 as a boundary. That is, the crystal orientation deviation at the boundary of the central portion of the bonding layer 3 is substantially the same crystal orientation deviation as the crystal orientation deviation between the adjacent bonding bodies 2. Accordingly, the deviation between the crystal orientation of the bonding layer 3 sandwiched between the adjacent bonding bodies 2 and the crystal direction of the adjacent bonding bodies 2 can be within 15 degrees.

  In an oxide superconductor, a crystal grain boundary with a large inclination becomes a weak bond that inhibits the superconducting current. However, as in this embodiment, since the deviation in crystal orientation between the bonding layer and the adjacent bonding body 2 is small, the bonding portion The superconducting current is not significantly hindered. Therefore, the superconducting bulk bonded body 1 exhibits good superconducting characteristics.

  In the superconducting bulk bonded body 1 in the present embodiment, the melting temperature differs between the bonding body 2 and the bonding layer 3. About each melting temperature, it can investigate by heating up the small test piece which cut out each part, and measuring the temperature which the said small test piece melts.

  Further, if the slow cooling rate in the process of manufacturing the superconducting bulk bonded body 1 is too high, the crystal growth of the bonding layer 3 is disturbed, and the superconducting characteristics of the bonding layer 3 are remarkably deteriorated. Therefore, the slow cooling rate is preferably 3 K / hour or less, more preferably 1 K / hour or less. Further, the slow cooling needs to be performed at least until reaching a temperature at which the molten bonding layer 3 crystallizes. The temperature at which the molten bonding layer 3 is crystallized varies depending on the type of rare earth element and the silver content, but is preferably gradually cooled to a temperature of 1233K to 1213K.

  As a method for producing the bonding layer 3, a method in which powder is spread, a method in which powder is molded, sintered or melted and solidified is sandwiched between the bonding bodies 2, and a mixture with an organic binder is applied to the bonding surface of the bonding body 2. A method or a method of forming a film on the bonding surface of the bonding body 2 by sputtering or the like is used.

  As in the present embodiment, the bonding body 2 and the bonding layer 3 are arranged in the lateral direction (horizontal direction), the bonding body 2 is supported using the support member 5, and the arrangement direction of the bonding body 2 and the bonding layer 3 is horizontal. In the case where the bonding layer 3 is made of a powder spread method or a powder molding method, the bonding layer 3 portion is in the process of arranging the bonding body 2 and the bonding layer 3 before heat treatment. There is a risk of falling. Therefore, it is preferable to use a sintered or melted / solidified oxide superconductor as the bonding layer 3.

  Furthermore, when the oxide superconductor sintered or melted / solidified is used as the bonding layer 3, for example, if the thickness of the bonding layer 3 is 0.2 mm or less, the bonding layer 3 is light and can be held by frictional force. Therefore, the possibility of falling becomes smaller.

  However, the possibility of dropping is not zero even with the bonding layer 3 having such a thin thickness. Moreover, the possibility of dropping becomes higher in the thick bonding layer 3 having a thickness of 0.2 mm or more. Therefore, in order to prevent the bonding layer 3 from dropping and to support the bonding body 2 horizontally by the support member 5 so that the bonding layer 3 does not directly touch the substrate 4, it is necessary to take some measures to prevent the dropping. .

  Such measures to prevent dropping include pressurization and adhesion. First, regarding the prevention of dropping by pressurization, it is necessary to pressurize the joining body 2 and the joining layer 3 in the arrangement direction in an electric furnace that is at a high temperature. Then, in the case of the vertical arrangement in the vertical direction, for example, the weight can be relatively easily applied by placing a weight on these upper portions. However, in the case of a horizontal arrangement in which the bonding body 2 and the bonding layer 3 are arranged in the horizontal direction as in the present embodiment, it is necessary to apply pressure in the horizontal direction, and pressurization is not easy. For example, means for converting the load applied in the vertical direction using a wedge or the like into the horizontal direction, means for applying pressure in the horizontal direction with a heat-resistant alumina vise, or the like can be considered. However, it can be said that it is difficult to provide a pressurizing mechanism that pressurizes the joining body 2 and the joining layer 3 in the horizontal direction in a high-temperature electric furnace, which is not practical.

  On the other hand, as a countermeasure for preventing dropping by bonding, the bonding body 2 and the bonding layer 3 may be bonded with an organic adhesive such as polyvinyl alcohol. Thereby, since the joining layer 3 is fixed to the joining main body 2, the joining layer 3 is prevented from falling, and workability can be greatly improved. An organic adhesive such as polyvinyl alcohol decomposes or evaporates during heating or when the bonding layer 3 is in a semi-molten state, so that it hardly affects the superconducting characteristics of the superconducting bulk bonded body 1.

  Further, silver does not affect the superconducting characteristics of the superconducting bulk bonded body 1. Therefore, the above effect can be obtained even when a silver paste is used as the bonding means. Therefore, means for bonding the bonding body 2 and the bonding layer 3 with an organic adhesive or silver paste is superior in each stage in terms of improving workability. That is, an adhesion means using an organic adhesive or silver paste is more preferable as a measure for preventing the bonding layer 3 from falling.

  The portion of the bonding layer 3 is once in a semi-molten state during the heat treatment. Therefore, if the thickness of the bonding layer 3, in other words, the interval between adjacent bonding bodies 2 is long, the bonding layer 3 may flow out from between the bonding bodies 2 when the bonding layer 3 is in a semi-molten state. If the bonding layer 3 is formed by film formation or coating, the thickness is about several μm to several tens μm and several hundreds μm, and there is no particular problem. On the other hand, when the bonding layer 3 is produced by a method of spreading the powder or a method in which the powder is molded, sintered or melted and solidified and sandwiched between the bonding bodies 2, the thickness is preferably, for example, 3 mm or less, If it is 1 mm or less, it is more preferable.

  Next, the shape and installation example of the support member 5 according to the present embodiment will be described. 2A to 2F are perspective views showing examples of the shape and installation of the support member 5 according to the present embodiment. In FIG. 2A to FIG. 2F, the substrate 4 is omitted.

  FIG. 2A is an example of a support member 5 a that is plate-shaped and slightly smaller than the joining body 2. Even if the bonding layer 3 is in a semi-molten state in the heat treatment step by arranging the support member 5a to be smaller than the bonding body 2 and not to overlap the bonding layer 3, the bonding layer 3 is a substrate. It is possible to avoid touching 4 directly. Moreover, since the supporting member 5a of FIG. 2A is plate-shaped, it is excellent in the point which can support the joining main body 2 stably.

  FIG. 2B is an example in which the length of the support member 5a shown in FIG. 2A in the juxtaposed direction of the joining body 2 and the joining layer 3 is shortened to reduce the contact area between the joining body 2 and the support member 5b. is there. Although the amount of impurities mixed into the bonding body 2 is smaller than that of the bonding layer 3, it is not completely zero. In order to suppress the mixing of impurities into the bonded body 2 as much as possible, it is preferable to reduce the contact area between the bonded body 2 and the support member 5b as much as possible as in the configuration shown in FIG. 2B.

  FIG. 2C is an example in which the number of support members 5b shown in FIG. 2B is increased. If the contact area between the bonding body 2 and the support member 5c is reduced, it becomes difficult to support the bonding body 2 horizontally. Therefore, as shown in FIG. 2C, the bonded main body 2 can be supported more stably by supporting the single bonded main body 2 with a plurality of support members 5 c.

  FIG. 2D is an example in which the support member 5c shown in FIG. 2C is deformed into a triangular prism shape. By making the shape of the support member 5d a triangular prism, the contact area between the joining main body 2 and the support member 5d can be further reduced. 2D includes a substantially triangular prism shape. That is, when the corner portion serving as the support point of the joint body 2 is pointed, the joint body 2 and the support member 5d are in line contact, but if the corner portion is chamfered, the joint body 2 and the support member. Needless to say, 5d is in surface contact.

  FIG. 2E is an example in which the joining body 2 is supported by a columnar support member 5e. In the example shown in FIGS. 2A to 2D, the width of the support member 5 (the length in the Y-axis direction) is approximately the same as the width of the bonded body 2. However, the support member 5 according to the present embodiment is not limited to such an example. For example, as shown in FIG. 2E, by reducing the width of the support member 5e, the contact area between the joining body 2 and the support member 5e can be further reduced. 2E shows an example of the columnar support member 5e, the shape of the support member 5e is not particularly limited, and may be, for example, a hollow cylindrical shape, a conical shape, or a triangular prism shape.

  FIG. 2F shows an example in which the number of support members 5e shown in FIG. 2E is increased. If the contact area between the bonded main body 2 and the support member 5e is reduced, it may be difficult to support the bonded main body 2 horizontally. Therefore, as shown in FIG. 2F, the joint body 2 can be supported more stably by supporting one joint body 2 with a plurality of support members 5f.

  Next, an example of the arrangement of the support members 5 according to this embodiment will be described. 3A to 3F are bottom views showing examples of the arrangement of the support members 5 according to the present embodiment. In FIG. 3A to FIG. 3F, the substrate 4 is omitted.

  FIG. 3A is a bottom view of the configuration corresponding to the perspective view of FIG. 2E, and is an example in which one joining body 2 is supported by one support member 50a.

  FIG. 3B is a bottom view of the configuration corresponding to the perspective view of FIG. 2F, and is an example in which one joining body 2 is supported by two support members 50 b. By supporting one joining body 2 with a plurality of support members 50b, the joining body 2 can be supported more stably.

  FIG. 3C is another example in which one joining main body 2 is supported by two supporting members 50c. As can be seen by comparing FIG. 3B and FIG. 3C, even if the number of support members 50b (50c) is the same, several arrangement patterns are conceivable. Such an arrangement pattern can be appropriately selected according to the size of the superconducting bulk bonded body 1 to be manufactured, the situation in the electric furnace, and the like.

  FIG. 3D is an example in which four support members 50d that support one joint body 2 are arranged in a square shape, and FIG. 3E is a diagram in which three support members 50e that support one joint body 2 are arranged in a triangle shape. It is an example. Rather than arranging the support members 50b (50c) linearly as shown in FIGS. 3B and 3C, as shown in FIGS. 3D and 3E, the support member 50d (50e) is a flat surface such as a rectangle or triangle. Therefore, the joining body 2 can be supported more stably.

  In the example shown in FIGS. 3A to 3E, the example in which the joining members 2 are arranged in the same manner as the arrangement method of the support members 50 that support the joining bodies 2 is shown. However, if the joining body 2 can be stably supported in the horizontal direction, for example, as shown in FIG. 3F, the joining body 2 is supported in an arrangement in which the manner of arrangement of the support members 50f is different for each joining body 2. It doesn't matter.

(Other aspects of superconducting bulk bonded body)
In FIG. 1, an example of a method of manufacturing a superconducting bulk bonded body 1 by bonding two rectangular bonding bodies 2 is shown, but the shape and the like of the manufactured superconducting bulk bonded body 1 are shown in FIG. 1. The present invention is not limited to the rectangular shape as shown, and various modes are conceivable.

  FIG. 4 is a conceptual diagram showing a method of manufacturing the superconducting bulk bonded body 1A according to a modification of the present embodiment. FIG. 4 is an example showing the arrangement of the bonding body 2 and the bonding layer 3 when a plurality of long bonding bodies 2 are bonded to produce a long superconducting bulk bonded body 1A. In order to manufacture such a long superconducting bulk bonded body 1A, it is very difficult and practically impossible to arrange the bonding body 2 and the bonding layer 3 in the vertical direction (vertical arrangement). Moreover, in the example shown in FIG. 1, the number of the joining main bodies 2 is two, but in the example shown in FIG. 4, the number of the joining main bodies 2 is three. As described above, by using the support member 5, it is possible to manufacture the superconducting bulk bonded body 1 </ b> A, which is obtained by increasing the number of the bonded main bodies 2, while stably supporting it.

  FIG. 5 is a conceptual diagram showing a method for manufacturing the superconducting bulk bonded body 1B according to a modification of the present embodiment. 1 and 4 show an example in which the bonding body 2 and the bonding layer 3 are arranged only in the horizontal direction. However, in FIG. 5, a portion in which the bonding body 2 and the bonding layer 3 are arranged in the horizontal direction, and the bonding body 2. And an example including both portions where the bonding layer 3 is arranged in the vertical direction. In the example shown in FIG. 5, another joining body 2 is laminated in the vertical direction via a joining layer 3 on each outer end of two joining bodies 2 arranged in the horizontal direction. In this case, the joining main bodies 2 stacked in the vertical direction are supported by the joining main bodies 2 arranged in the horizontal direction. Even in the case of manufacturing the superconducting bulk bonded body 1B including both the horizontal arrangement and the vertical arrangement, the oxide that becomes the bonding layer 3 can be obtained by using the supporting members 5 that horizontally support the bonding bodies 2 in the horizontal arrangement. Since the superconductor does not directly touch the substrate 4, the superconducting bulk bonded body 1B having good superconducting characteristics can be manufactured.

  Further, both the bonding body 2 and the bonding layer 3 may contain silver. Thereby, the mechanical strength of the joint portion of the superconducting bulk joined body 1 can be improved. Examples of a method for containing silver in the bonding body 2 and the bonding layer 3 include, for example, in the process of manufacturing the powder of the bonding body 2 and the bonding layer 3, a silver compound powder such as silver oxide or a metal silver powder. There is a method of adding to powder, mixed powder, calcined powder or the like. In this case, silver is finally present mainly in the form of silver particles in the superconducting bulk bonded body 1 regardless of whether silver oxide powder or metallic silver powder is added.

  In addition, it is preferable that content of the silver in the joining main body 2 and the joining layer 3 is 2 to 30 mass% in conversion of metallic silver. If the silver content is greater than 30% by mass, the effect of improving the mechanical strength is small, and the action of inhibiting the molten bonding layer 3 portion from growing as a seed crystal with the bonding body 2 is increased. . Moreover, if content of silver is 2 mass% or more, the effect which improves mechanical strength will be exhibited more fully.

Example 1
In this example, the effectiveness of the method for manufacturing a superconducting bulk joint according to this embodiment will be described with reference to FIGS. 6A and 6B. FIG. 6A is a conceptual diagram for explaining an aspect of the bonding body 2 and the bonding layer 3 constituting the superconducting bulk bonded body 10. FIG. 6B is a perspective view showing an arrangement example of each member in the method of manufacturing the superconducting bulk bonded body 10.

  First, a manufacturing procedure of a single-crystal oxide superconducting bulk body for cutting out the joining body 2 constituting the samples A to C 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 obtained by using Gd: Ba: Cu = 1.6: 2.3: 3. The mixture was weighed at a molar ratio of 3, and 1% by mass of cerium oxide and 10% by mass of silver oxide in terms of silver were added thereto. The weighed powder was sufficiently kneaded over 2 hours and then calcined at 1173 K for 8 hours in the air.

Next, the calcined powder was formed into a disk shape using a mold. This molded body was heated to 1423K to be in a molten state, held for 30 minutes, and then seeded in the middle of lowering the temperature, and a temperature range of 1278K to 1252K was gradually cooled over 100 hours to grow a crystal, having a diameter of 50 mm and a height of A 15 mm single crystal bulk body was obtained. Then, as shown in FIG. 6A, two rectangular samples of 10 mm (W ₀ ) × 15 mm (L ₁ ) × 4 mm (T ₀ ) are used as a bonding main body from the single crystal bulk body having a diameter of 50 mm. The c-axis was cut out so as to be parallel to a 4 mm long side. The sample is a sample corresponding to the bonding body.

  Next, powders of oxides of yttrium (Y), barium (Ba), and copper (Cu) having a purity of 99.9% by mass, which are commercially available, are obtained as follows: Y: Ba: Cu = 1.6: 2.3 : Weighed at a molar ratio of 3.3, and added 1% by mass of cerium oxide and 10% by mass of silver oxide in terms of silver. The weighed powder was sufficiently kneaded over 2 hours and then calcined at 1173 K for 8 hours in the air.

Next, the calcined powder was formed into a disk shape using a mold, and this formed body was sintered at 1223K for 8 hours to obtain a sintered body having a diameter of 30 mm and a height of 10 mm. One rectangular sample of 10 mm (W ₀ ) × 1 mm (L ₂ ) × 4 mm (T ₀ ) was cut out as a bonding layer from the sintered body having a diameter of 30 mm. The sample is a sample corresponding to the bonding layer 3.

The oxide to be the bonding body 2 and the bonding layer 3 is RE ₁ Ba ₂ Cu ₃ O _y (RE is one or more elements selected from the group consisting of Y and rare earth elements, and y is oxygen It consists of an oxide superconductor in which RE ₂ BaCuO ₅ is dispersed in an amount of 6.8 ≦ y ≦ 7.1). Moreover, when the melting temperature of the oxide used as the joining main body 2 and the oxide used as the joining layer 3 was measured (measured in the site | part which remained after cutting), they were 1277K and 1243K, respectively.

  First, the sample A will be described. As shown in FIG. 6B, the sample A was applied in a horizontal direction after thinly applying a polyvinyl alcohol-based organic adhesive to the joining surfaces of the two joining bodies 2 and one joining layer 3 cut out as described above. They are arranged side by side. In addition, two cylindrical support members 51 having a diameter of 6 mm and a height of 10 mm are arranged on the alumina substrate 4, and the sample body 2 is placed on each of the support members 51. A was placed. That is, the configuration in which the sample A shown in FIG. 6B is supported by the support member 51 corresponds to the arrangement configuration according to the method for manufacturing a superconducting bulk bonded body of the present invention.

  For comparison, a sample B having a bonding body 2 and a bonding layer 3 having the same size and the same material as the sample A was prepared. In Sample B, as shown in FIG. 6B, the bonding body 2 and the bonding layer 3 were arranged in the horizontal direction in the same manner as Sample A, but these were directly arranged on the substrate 4 without using a support member.

  Furthermore, for comparison, a sample C having the same size and the same material as those of the sample A and the sample B and the bonding body 2 and the bonding layer 3 was prepared. As shown in FIG. 6B, the sample C differs from the sample A and the sample B in that the bonding body 2 and the bonding layer 3 are arranged in the vertical direction and directly arranged on the substrate 4. The arrangement of the sample B and the sample C corresponds to the arrangement in the conventional method for manufacturing a superconducting bulk joined body. In addition, since there is no possibility that the bonding layer 3 falls in the configurations of the sample B and the sample C, no adhesive is applied to the bonding body 2 and the bonding layer 3.

  Next, the substrate 4 on which the sample A, the sample B, and the sample C were placed was moved and placed in an electric furnace. At that time, the sample C fell several times in the middle of installing the substrate 4 in the electric furnace, so that the sample C was rearranged in the vertical direction each time. Next, each sample installed in the electric furnace was heated to 1258K, held for 1 hour, and then gradually cooled to 1223K over 35 hours. The superconducting bulk joined body thus obtained was heat-treated at 723 K for 100 hours in an oxygen stream.

  When the electric furnace was opened and confirmed after the heat treatment, the joining body 2 and the joining layer 3 according to the samples A and B were sufficiently joined, and each constituted one superconducting bulk joined body. On the other hand, the sample C was overturned in the electric furnace, and the joining body 2 and the joining layer 3 were not joined and were apart. This is presumed that the sample C fell down due to some cause (for example, a small vibration accompanying the operation of the electric furnace) during the heat treatment process. From this, in the production of the long superconducting bulk bonded body 10, the vertical arrangement in which the bonding main body 2 and the bonding layer 3 are arranged in the vertical direction is compared with the horizontal arrangement in which the bonding main body 2 and the bonding layer 3 are arranged in the horizontal direction. It was confirmed that the balance was unstable and unstable.

  Next, the superconducting bulk bonded body of sample A and sample B that have been sufficiently bonded is magnetized by a magnetic field cooling method that cools in liquid nitrogen in a magnetic field of 1 T, and the surface of these samples is scanned by a Hall element. The captured magnetic field distribution was measured.

  7A and 7B are graphs showing the measurement results of the captured magnetic field distributions of Sample A and Sample B. FIG. 7A and 7B are diagrams showing the positions of the bonding body 2 and the bonding layer 3 corresponding to the captured magnetic field distribution.

  As shown in FIG. 7A, in the trapped magnetic field distribution of sample A, no decrease in magnetic field strength was observed at the bonding layer 3 portion, and the magnetic field strength at the position of the bonding layer 3 was 0.18T. On the other hand, as shown in FIG. 7B, in the trapped magnetic field distribution of sample B, a decrease in magnetic field strength is observed in the bonding layer 3 portion, and the magnetic field strength at the position of the bonding layer 3 is 0.09 T. It was about half.

  Therefore, from this result, the support member 5 is disposed so as to maintain the bonding body 2 in the horizontal direction, and the bonding layer 3 is not directly touched to the substrate 4, so that the bonding body 2 and the bonding layer 3 are horizontally aligned. It was shown that the superconducting bulk bonded body 1 having excellent superconducting characteristics can be manufactured even when arranged.

(Example 2)
In the present embodiment, the influence on the superconducting characteristics due to the arrangement of the support member in the method of manufacturing a superconducting bulk bonded body will be described with reference to FIG. FIG. 8 is a perspective view showing an example of the arrangement of the support members in the method for manufacturing the superconducting bulk bonded body 10. Sample D, Sample E, Sample F, and Sample G in this example are prepared using the same size and the same material as the bonding body 2 and the bonding layer 3 of Sample A according to Example 1 described above. Are different in shape, size, and arrangement.

  For sample D, as shown in FIG. 8, support members were arranged in the same manner as sample A to support each of the bonded main bodies 2. Specifically, for the sample D, four columnar support members 51 made of alumina having a diameter of 6 mm and a height of 10 mm are arranged on the substrate 4, and two support members 51 per one bonding body 2 are arranged. Used to support each of the bonded bodies 2. That is, Sample D was manufactured under the same conditions as Sample A of Example 1.

  For sample E, as shown in FIG. 8, two rectangular support members 52 made of alumina having a width of 10 mm, a length of 12 mm, and a height of 6 mm are arranged on the substrate 4, and one per bonded body 2. Each of the joining main bodies 2 was supported using a single support member 52. In other words, in the sample E, the size of the support member 51 is made slightly smaller than that of the bonding body 2 so that the bonding layer 3 does not directly touch the support member 52.

  For the sample F, as shown in FIG. 8, four square bar-shaped support members 53 made of alumina having a width of 15 mm, a length of 2 mm, and a height of 2 mm are arranged on the substrate 4, and 2 per one bonded body 2. Each of the joining main bodies 2 was supported using a single support member 53. At that time, the support member 53 was disposed so that the longitudinal direction thereof was the horizontal direction. For sample G, two columnar support members 54 made of alumina having a diameter of 6 mm and a height of 10 mm are arranged on the substrate 4 and bonded using one support member 54 per bonded body 2. Each body 2 was supported. At that time, the support member 54 was disposed such that the longitudinal direction was the vertical direction.

  Next, the substrate 4 carrying the sample D, the sample E, the sample F, and the sample G was moved and placed in an electric furnace. Next, each sample installed in the electric furnace was heated to 1253K, held for 1 hour, and then gradually cooled to 1223K over 30 hours. The superconducting bulk joined body thus obtained was heat-treated at 723 K for 100 hours in an oxygen stream.

  When the electric furnace was opened and confirmed after the heat treatment, the bonding body 2 and the bonding layer 3 related to the sample D, the sample E, and the sample F were sufficiently bonded to each other to constitute one superconducting bulk bonded body. On the other hand, although the joining body 2 and the joining layer 3 related to the sample G are sufficiently joined, the two joining bodies 2 are joined with a slight deviation compared to the samples D, E, and F. It was confirmed visually.

  In sample G, each joint body 2 is supported by using only one support member 54 having a small contact area, so that it is inferred that a small deviation occurred between the two joint bodies 2 during the heat treatment process. Is done. Actually, the position of the support member 54 when the sample G was manufactured was slightly shifted from the center position of each joint body 2. Therefore, the position of the support member 54 that supports the joining body 2 of the sample G shown in FIG. 8 is newly adjusted as the sample G ′ so as to be in the center of each joining body 2, and heat treatment is performed again. Then, the bonding body 2 and the bonding layer 3 according to the sample G ′ were sufficiently bonded, and a superconducting bulk bonded body without a small deviation between the two bonding bodies observed in the sample G was obtained.

  Next, the superconducting bulk bonded bodies according to Sample D, Sample E, Sample F, Sample G, and Sample G ′ are magnetized by a magnetic field cooling method in which liquid nitrogen is cooled in a magnetic field of 1 T, and these are formed by a Hall element. The captured magnetic field distribution was measured by scanning the sample surface.

  FIG. 9 is a graph showing the results of the captured magnetic field strength in the bonding layer 3 of each sample. In FIG. 9, the magnetic field strength related to the sample B of Example 1 (that is, the sample subjected to the heat treatment with the bonding body 2 directly disposed on the substrate 4) is displayed as a reference. As shown in FIG. 9, it was confirmed that Sample D, Sample F, and Sample G ′ having relatively small contact areas between the bonding body 2 and the support member 5 have good superconducting characteristics. Further, in the sample E in which the contact area between the bonding main body 2 and the support member 5 is relatively large and the sample G in which the two bonding main bodies 2 are bonded to each other, the magnetic field strength in the bonding layer 3 is slightly higher than that of other samples. Although it decreased, it was more than 1.5 times the magnetic field strength of Sample B. Therefore, it has been confirmed that the superconducting characteristics are greatly improved in the manufacturing method using the support member 5 according to the present embodiment as compared with the case where the bonding body 2 is directly arranged on the substrate, which is a conventional manufacturing method.

  Therefore, from this result, the support member 5 is disposed so as to maintain the bonding body 2 in the horizontal direction, and the bonding layer 3 is not directly touched to the substrate 4, so that the bonding body 2 and the bonding layer 3 are horizontally aligned. It was shown that the superconducting bulk bonded body 1 having excellent superconducting characteristics can be manufactured even when arranged. Moreover, it was shown that the superconducting bulk bonded body 1 having further excellent superconducting characteristics can be manufactured by further reducing the contact area between the bonding body 2 and the support member 5.

  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 1, 10 Superconducting bulk bonded body 2 Bonding main body 3 Bonding layer 4 Substrate 5, 50

Claims (5)

A plurality of junction bodies formed of first oxide superconductors having a uniform crystal orientation are arranged so that the deviation of the crystal orientations of the adjacent junction bodies is within 15 °, and the adjacent junctions Arrangement in which a bonding layer formed by a second oxide superconductor having a material property having a melting temperature lower than that of the first oxide superconductor is placed between the main bodies so as to be in contact with each other. Process,
The plurality of bonding bodies and the bonding layer are heated to a temperature lower than the melting temperature of the bonding body and higher than the melting temperature of the bonding layer, and then the bonding layer is melted, and then at least the bonding layer Is a method of manufacturing a superconducting bulk bonded body, comprising: a step of gradually cooling to a temperature at which crystallization occurs and bonding the adjacent bonded bodies adjacent to each other via the bonding layer,
In the arranging step, while supporting each of the plurality of bonding bodies using at least one support member per bonding body, the plurality of bonding bodies and the bonding layer are disposed in a horizontal direction,
In the heat treatment step, the bonding bodies adjacent to each other are bonded to each other through the bonding layer in a state where the arrangement direction of the bonding bodies supported by the support member and the bonding layer is maintained in a horizontal direction. A method of manufacturing a superconducting bulk joined body.   2. The method of manufacturing a superconducting bulk bonded body according to claim 1, wherein, in the arranging step, each of the plurality of bonded main bodies is supported using a plurality of the supporting members per one bonded main body.   The method for manufacturing a superconducting bulk bonded body according to claim 1 or 2, wherein the bonding main body and the bonding layer are bonded with an organic adhesive or silver paste. The first oxide superconductor and the second oxide superconductor are RE ₁ Ba ₂ Cu ₃ O _y (RE is one or more elements selected from the group consisting of Y and rare earth elements) Y is an amount of oxygen, and is an oxide superconductor in which RE ₂ BaCuO ₅ is dispersed in 6.8 ≦ y ≦ 7.1). A method of manufacturing a superconducting bulk bonded body.   The superconducting bulk joining according to any one of claims 1 to 4, wherein the joining main body and the joining layer contain 2% by mass to 30% by mass of silver in terms of metallic silver. Body manufacturing method.

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