WO1995024047A1 - Superconducting magnet and production method thereof - Google Patents

Abstract

A superconducting coil magnet made of superconducting single-crystal oxide is produced either by shaping a crystallized superconducting material into a spiral shape or by crystallizing a molded article of powder in a spiral shape. The superconducting coil magnets are then laminated so as to produce an oxide superconducting magnet capable of generating a greater magnetic field by the supply of power from outside.

Description

 Description Superconducting magnet and manufacturing method

The present invention substantially relates to REBa ₂ Cu ₃ 0 ₇ — X (0 ≤ x ≤ 0.3) (RE is any one of Y, La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb, Lu) relates element or superconducting the magnet preparative and manufacturing method thereof using these combination) and the oxide superconducting material consisting of RE ₂ BaCu0 ₅ Prefecture. Background art

Currently, the most practical superconducting magnets are Nb-Ti based superconducting wires wound around coils. In addition, Nb ₃ Sn or V ₃ Ga superconducting materials have been made into wires and coiled and used as superconducting magnets for high magnetic fields. Since these metallic superconducting magnets have a low critical temperature, they need to be cooled to extremely low temperatures using liquid helium or the like. Although superconducting magnets have excellent properties as magnetic field generators, their necessity for cooling at extremely low temperatures has not yet spread widely.

On the other hand, since the discovery of oxide high-temperature superconductors, research and development of magnets using oxide superconductors having a critical temperature of 77K or higher that can be cooled and used with inexpensive and easy-to-handle liquid nitrogen have been actively conducted. Have been done. At present, the mainstream method is to pack a Bi-based material into a sheath, process it into a tape, create a silver sheath tape material containing an oriented superconducting material, and wind it around a coil. . However, such a tape material does not have a sufficient critical current density (Jc) at 77K and has not been put to practical use. Compared to such a general method of manufacturing a magnet that turns the oxide superconductor into a wire and then turns it into a coil, it considers the difficult processability associated with the brittleness that is a disadvantage of the oxide superconductor. In addition, it has been studied to produce a coil-shaped sintered body by heat treatment without using plastic deformation and to use it as a magnet (Japanese Patent Application Laid-Open No. 63-261808). However, a sintered body (especially Y-based) basically contains many grain boundaries, which become superconducting weak bonds and cannot obtain a high critical current density. Therefore, it is difficult for a magnet made of a sintered body to generate a high magnetic field while maintaining a superconducting state (JP-A-63-261808).

Currently, the bulk material can be used as a magnetic Tsu Bok material having a high Jc even in a high magnetic field at 77K is a single crystalline REBa ₂ Cu ₃ 0 ₇ - RE in _{x 2} BaCu0 ₅ fine Only dispersed materials (so-called QMG materials). For QMG materials, it is now possible to produce large single crystal materials by the Pt addition method and seeding.

The magnet using the QMG material was first disclosed in Japanese Utility Model Laid-Open No. 4-15811. This is to form a solenoid-shaped coil by cutting into a cylindrical QMG superconductor. The magnetic field generated by the magnet is given by the product of the energizing current and the coil constant.The coil constant varies depending on the number of turns and the winding method, and when used below the critical density, increase the number of turns, etc. By increasing the constant, a large magnetic field can be obtained with a low current. As can be seen from the figure in Japanese Utility Model Application Laid-Open No. 4-15811, such a solenoid-shaped magnet is formed by reducing the wire diameter and increasing the number of windings from the viewpoint of imparting shape. It is difficult to increase the constant. Therefore, the development of a new type of magnet having a large coil constant using a QMG material and a method of manufacturing the same, rather than a solenoid-type coil cut into a cylinder, has become an issue. Disclosure of the invention

 The present invention solves the above-mentioned problems, and has a

REBa ₂ Cu ₃ 0 phase (RE is a rare earth element and the combination of them including Y) has a tissue RE ₂ BaCu0 ₅ is finely dispersed in the superconducting, characterized in that it comprises a spiral coil shape It is a magnet. The Oite Here, REBa ₂ Cu ₃ 0 ₇ - direction of the c-axis of the crystal orientation of the _x phase has one assortment two within 40 degrees, and that it contains one least be of Pt or Rh traces, the c The axis must be aligned within 20 degrees with respect to the normal of the plane constituting the spiral, the cross-sectional area of the conductor inside the spiral is larger than the cross-sectional area of the outer conductor, and the spiral It is also characterized by being reinforced by the presence of resin in at least a part of the gap between the superconductors.

Further, the present invention is a superconducting magnet characterized in that a plurality of the above-mentioned spiral coils are laminated. Here, the spiral direction (right-handed or left-handed) of the adjacent layers is alternated.-The ends of each stacked coil are connected by a metal having high electrical conductivity. has been has or laminated each spiral between the ends of the coil of the coil conductor Tf - REBa ₂ is a superconductor having a lower Tf (REBa ₂ Cu ₃ 0 ₇ generation temperature of the _x-phase) that are connected by Cu ₃ 0 phase, the thickness of the central portion a layer of spiral coils of the multi-layer is summer thicker than the thickness of the layer of the spiral coil end portions, between the eyebrows of each spiral Koi Le It is also characterized by being reinforced by the presence of resin at least in part.

The addition Is start of a coil formed by a spiral coil of one or more layers of al the and the termination, ₃ 0 ₇ single crystalline REBa ₂ Cu - RE ₂ BaCuO _s is finely dispersed in the _x phase A closed circuit composed of a superconductor is formed by connecting using an oxide superconducting material This superconducting magnet is characterized by comprising an introduction terminal and a superconducting switch.

The present invention is a single crystalline REBa ₂ Cu ₃ 0 ₇ - this cuts made after cut out a plate-shaped material from the oxide superconducting material having a tissue RE ₂ BaCu0 ₅ was dispersed fines in _x phase This is a method for manufacturing a superconducting magnet, characterized in that it is processed into a spiral coil shape by the above method. Here, it is also characterized in that after the plate-shaped superconductor is fixed to the support base with an adhesive, a spiral processing is performed by water jet cutting.

Alternatively, a compact is manufactured from a powder containing oxides of RE, Ba, and Cu, and the compact is processed into a spiral coil shape, and then turned into a semi-molten state composed of a 211 phase and a liquid phase. heating, then oxidizing atmosphere at a gradual cooling child single crystalline 1 ^ 8 & ₂ (: 11 ₃ 0 _{7 -) (1} ^ ₂ 8 & during phase (; 1] 0 ₅ is finely dispersed structure A method for producing a superconducting magnet characterized by forming a superconducting material having the following characteristics: In addition, another molded body is disposed on the spiral molded body so as to cover the spiral molded body. However, they are also characterized in that they are heated to a semi-molten state composed of a 211 phase and a liquid phase, then the crystal orientation is controlled by a seed crystal, and the crystal is gradually cooled in an oxidizing atmosphere.

The superconducting magnet is characterized in that the spiral coils produced by the above method are stacked so that the spiral direction (right-handed or left-handed) is alternated, and the coils are electrically connected. It is a manufacturing method. As entire coil stacked in here is superconductor, REBa ₂ Cu ₃ 0 ₇ a superconducting phase having a lower Tf than Tf of the spiral coil conductors - each spiral of a material consisting of _x phase It is also characterized by connecting the ends of the coil. Also, the one of REBa beginning and a termination single crystalline of Koiru formed by the method _{2 Cu 3 0 7 - RE 2} BaCu0 5 in _x phase are connected by a superconducting material having a finely dispersed organizations This is a method for manufacturing a superconducting magnet characterized by this. BRIEF DESCRIPTION OF THE FIGURES

 Fig. 1 shows the appearance of the spiral coil, (A) is a plan view,

 (B) is a front view.

 FIG. 2 is a diagram showing the relationship between the shape of the spiral coil and the crystal orientation. FIG. 3 is a partial cross-sectional perspective view showing one embodiment of a method for laminating the spiral coil.

 FIG. 4 is a perspective view showing another embodiment of the method of laminating the spiral coil, (A) before lamination and (B) after lamination.

 FIG. 5 is a perspective view showing one embodiment of a method for processing a molded body.

 FIG. 6 is a view showing another embodiment of a method for processing a molded body, (A) is a perspective view of the whole, and (B) is a plan view in which a part thereof is enlarged.

 FIG. 7 is a front view showing a compact placed in the furnace.

 FIG. 8 is a view showing one embodiment of the superconducting joining method, (A) is a perspective view showing a processed state at a joint portion of the coil, (B) is a side view of a joined portion after heat treatment, and (C) is a side view. Fig. 8 is a partially enlarged view of Fig. 8 (B).

 Fig. 9 is a view showing an embodiment in which an Ag paste and a reinforcing resin are applied to a spiral coil, (A) is a plan view, and (B) is a partially enlarged view.

 FIG. 10 is a plan view showing another embodiment of the state of FIG.

 FIG. 11 is a diagram showing an example of a method of stacking spiral coils, wherein (A) shows a state before stacking and (B) shows a state after stacking.

 FIG. 12 is a graph showing an example of the magnetic field distribution on the axis of the superconducting magnet of the present invention.

 FIG. 13 is a plan view showing a spiral coil in which the cross-sectional area of the outer conductor is smaller than the cross-sectional area of the inner conductor.

 FIG. 14 is a perspective view showing another embodiment of the superconducting joining method.

FIG. 15 shows another example of the magnetic field distribution on the axis of the superconducting magnet of the present invention. It is a graph shown.

 FIG. 16 is a perspective view showing a laminated coil connected in a superconducting state. (FIG. 17 is a perspective view showing a superconducting joining method of a part of the laminated coil of FIG. 16.

 FIG. 18 is a graph showing another example of the magnetic field distribution on the axis of the superconducting magnet of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

 The material used for the magnet for superconductivity of the present invention is a single crystal.

_{REBa 2 Cu 3 0 7 - RE} 2 BaCu0 5 in _x phase is one having a finely dispersed tissue. Because in here the single crystalline is meant that also include those having a defect no problem in low-angle grain boundaries of throat practical rather than perfect single crystal _{(REBa 2} Cu ₃ 0 _7-phase (123-phase) and RE RE in the ₂ BaCu0 ₅ phase (211 phase) is a rare earth element consisting of Y, La, Nd, Sm, Bu, Gd, Dy, Ho, Er, Tm, Yb, Lu and their combinations, including La and Nd. The phase deviates from the stoichiometric composition of 1: 2: 3, and the site of RE may be partially substituted with Ba. Also in the 211 phase, La and Nd are Y, Sm, Bu, Gd, and La. It is somewhat different from Dy, Ho, Er, Tm, Yb, and Lu. It is known that the ratio of metal elements is non-stoichiometric and the crystal structure is different.

 The 123 phase is a peritectic reaction between the 211 phase and a liquid phase composed of a composite oxide of Ba and Cu,

 211 phase + liquid phase (composite oxide of Ba and Cu) → 123 phase

Can be done by The temperature at which the 123 phase is formed by the peritectic reaction (Tf 123 phase formation temperature) is almost related to the ionic radius of the RE element, and Tf decreases as the ionic radius decreases.

In the QMG material in which the 211 phase is finely dispersed in the single-crystal 123 phase, unreacted 211 grains are left in the 123 phase when the 123 phase grows. it can. That is, QMG material is

 21st liquid phase (composite oxide of Ba and Cu) → 123 phase + 211 phase

 Fine dispersion of 211 phase in QMG material is extremely important from the viewpoint of improving Jc. By adding at least one of Pt or Rh in a trace amount, the grain growth of the 211 phase in a semi-molten state (a state consisting of 211 phases and a liquid phase) is suppressed, and as a result, the 211 phase in the QMG material becomes finer. Become The addition amount is 0.2 to 2.0 wt% in Pt and Rh in Rh from the viewpoint of the amount that the miniaturization effect appears and the material cost.

0.01-0.5 wt% is desirable. The added Pt or Rh partially dissolves in the 123 phase. Elements that could not form a solid solution form complex oxides with Ba and Cu, and are scattered throughout the material.

 The superconducting magnet of the present invention is obtained by processing a QMG material into a spiral shape (mosquito coil) in a certain plane, thinning the wire, and producing a magnet having a large coil constant. Alternatively, by laminating spiral QMG materials, it is possible to produce magnets with a large coil constant (or number of turns), which was difficult with solenoid type coils. Specifically, first, the superconductor constituting the coil must have a high critical current density (Jc) even in a magnetic field. In order to satisfy this condition, it is necessary that the single-crystal 123 phase does not include a large-angle grain boundary that becomes superconducting and weakly bonded. In order to have higher Jc characteristics, a pinning center for stopping the movement of magnetic flux is required. What functions as this pinning center is the finely dispersed 211 phase, and it is desirable that a large number of finely dispersed phases be dispersed. As mentioned earlier, Pt and Rh have the function of promoting the refinement of this 211 phase. The 211 phase also plays an important role in mechanically strengthening the superconductor and forming a bulk material by finely dispersing it in the 123 phase, which is easily cleaved.

Such a superconductor (QMG material) is shown in Fig. 1 ((A) plan view, (B) As shown in Fig. 1), a magnet having a large coil constant can be made relatively easy by using a coil 1 made up of a plurality of conductors 11 that are spirally worked. Although Fig. 1 shows an example of an object with a relatively small inner diameter of the coil, a spiral-shaped object with a relatively large inner diameter can be considered in exactly the same way. An object with a relatively large inner diameter reduces the number of turns of the coil and reduces the generated magnetic field, but on the other hand has the advantage of obtaining a more uniform and wide magnetic field space. It is also evident from the example of an electromagnet composed of a copper coil and an iron core that the characteristics can be improved by inserting an iron core into the bore when the magnetic field generated by the coil is about 20 kGauss or less. In addition, Fig. 1 shows an almost concentric coil shape, but it is clear that an elliptical shape, a square shape, a hexagon shape, etc. can be considered in exactly the same way.

 There is no large-angle grain boundary in the QMG material, but there is a fluctuation in crystal orientation with small-angle grain boundaries of several degrees. This fluctuation depends on the crystal growth direction, and the part grown in the a-axis direction has a relatively large fluctuation distribution. Has a reporting power of around 36 degrees (Proceedings of 5th US -Japan workshop on high Tc superconductor and Adventures in Superconductivity II, Springer-Verlag Tokyo 1990). The single-crystal 123 phase described here is accompanied by such small-angle grain boundaries.

Next, the crystal structure of the 123 phase is two-dimensional and has the property of being easily cleaved along the a-b axis plane shown in Fig. 2. Therefore, cracks are likely to occur on the a-b axis plane, and such cracks cannot be completely eliminated at present. To prevent this crack from affecting the flow of superconducting current, the crack and the current must be parallel, that is, the c-axis of the crystal must be constantly perpendicular to the current 2 as shown in Fig. 2. Is ideal. However, the coil conductor has a swing of about 40 degrees in the c-axis direction. As shown in Fig. 2, it is desirable that the direction 3 of the c-axis be within ± 20 degrees with respect to the normal N of the plane when the coil is spirally wound in a plane due to the presence of turbulence. .

 Also, when the coil is energized and excited, the conductor inside the coil is exposed to a larger magnetic field than the outside conductor. Jc generally decreases as the magnetic field increases. Therefore, if a coil with the same cross-sectional area is energized, the inner conductor will reach a critical state first, breaking the superconductivity and damaging the coil itself. Therefore, it is desirable that the inner conductor has a larger cross-sectional area in accordance with the magnetic field characteristics of Jc.

 Furthermore, the conductor of the superconductor generating the magnetic field receives a force from the inside to the outside (Lorentz force) due to electromagnetic interaction. If this force exceeds the strength of the conductor, it will destroy the conductor. Therefore, in order to prevent coil destruction, it is necessary to mechanically connect and reinforce the conductors. To this end, it is effective to fill gaps between adjacent conductors with a non-superconducting substance and fix the conductors to each other. At this time, it is desirable that the non-superconducting material that bonds the conductor has a thermal expansion coefficient close to that of the conductor. A thermosetting resin is one example of this.

Subsequently, the above-mentioned spiral coils are stacked and connected between the ends, and the magnetic fields generated by the respective spiral coils are energized so that they reinforce each other, thereby forming a magnet that generates a stronger magnetic field. When stacking the same number of spiral coils, the highest generated magnetic field can be obtained by reducing the gap between the spiral coils and making them as close to each other as possible. For this purpose, as shown in Fig. 3, the spirals are stacked so that the direction of the spiral is the same, current 2 is aligned from inside to outside (or from outside to inside), and coils 1 are connected by plate conductors 4 There is a way to do it. However, as shown in Fig. 4 ((A) before lamination, (B) after lamination), the vortex The third direction is obtained by alternately reversing the direction (right-handed (1A, 1C) or left-handed (1B)) and connecting the inner and outer ends of coil 1 alternately. In the figure, a plate-like conductor that connects the coils, which was necessary in the figure, is not required, and the coils can be densely stacked by the thickness. In FIG. 4 (A), five connecting points are used. For example, the back surface 5A at the center end of the coil 1A, the front surface 5B at the center end of the coil 1B, and the back surface 5B-1 at the outer end of the coil 1B. And the outer end surface 5C of coil 1C.

 The coil located at the center of the spiral coil that has the eyebrows exposed to a higher magnetic field than the coil located at the end. Therefore, when current is applied to a laminated coil having the same cross-sectional area, the coil in the center reaches the critical state first, and superconductivity is broken, and the coil itself is damaged. Therefore, it is ideal that the cross-sectional area of the conductor of the coil at the center is larger in accordance with the magnetic field characteristics of Jc. For this purpose, it is desirable that the thickness of the spiral coil layer at the center is larger than the thickness of the spiral coil layer at the end.

 When lamination is performed, it is necessary to connect the ends of each spiral coil as described above.However, when the QMG material is cooled and energized, heat generation at this connection should be reduced to zero or as small as possible. Is desirable. If the heat generation is large, not only will the power consumption and the consumption of the refrigerant increase, but also the heat will degrade the superconducting properties of the superconducting conductor, causing a quench and burning the conductor itself. U. Due to such requirements, it is necessary to form an electrode with a low contact resistance and connect it with a metal having high electrical conductivity.

To completely eliminate the heat generated at the connection, all the current paths in the connection must be superconductors. In addition, the start and end are connected by a single-crystal QMG material so that the entire magnet becomes single-crystal. By installing a switch, a magnet that operates in permanent current mode can be created.

 The method for producing the superconducting magnet of the present invention is roughly classified into two methods for obtaining a coil shape. One is a method of imparting a coil shape after crystallization (GF method), and the other is a method of processing a compact into a coil shape and then crystallization (FG method).

 As an example of the GF method, a cylindrical bulk material is produced by a conventional technique, such as the improved QMG method (Advances in Superconductivity II, Springer-Verlag Tokyo 1992). This is sliced to a predetermined thickness and processed into a disk shape. For this slicing, cutting with a blade or the like in which diamond powder is embedded is suitable. Next, the disc-shaped QMG material is processed into a spiral shape. For spiral machining, machining with a small diamond point is also possible, but it is suitable for machining such as water jet cutting (a method in which high-pressure water is blown out of a thin nozzle to perform cutting). A good method is desirable. When water cutting is used, a method called abrasion, in which a hard powder (garnet powder, etc.) is mixed in water, is suitable. Also, in order to prevent the material from cracking due to the impact of water pressure, it is desirable to fix the material on a hard-to-deform base with resin or the like. In addition, the material may react with water, so it is desirable to dry it quickly after processing.

Next, an example of the FG method will be described. First, oxides of RE, Ba, and Cu are mixed so that a predetermined ratio of 211 phase: 123 phase is obtained. At this time, if Pt and Rh are added, the final structure 211 becomes finer. This mixed powder is processed and molded by a mold or the like to produce a molded body. Since this compact is a green compact, unlike a crystallized QG material, it can be easily processed using a drill or saw. For example, as shown in FIG. 5, a columnar molded body 6 can be formed into a coil shape by making cuts 7 at appropriate intervals by a thread saw. At this time, Fig. 6 As shown in ((A) Overall view, (B)-Enlarged plan view), by making the part 8 left uncut, deformation during semi-melting can be reduced.

 The processed coil-shaped compact 6 is superimposed on compacts 9, 10, and 11 having other RE compositions as shown in Fig. 7, and placed in the furnace. At this time, it is desirable from the viewpoint of crystal growth that an atmosphere can enter and leave the gap between the coil-shaped molded bodies 6. Since the coil-shaped formed body 6 has many cuts 7, the formed body 9 is formed so that the crystal grown from the seed crystal reaches the outside of the coil-shaped formed body 6 in the shortest distance. It is desirable to cover the top. Also, from the viewpoint of crystal growth, it is desirable that the molded body 9 has an RE composition equal to or higher than the RE composition of the coil-shaped molded body 6, which is equal to Tf.

 It is desirable that the molded body 10 has a RE composition of Tf lower than the Tf of the RE composition of the coil-shaped molded body 6, and that the molded body 11 has a RE composition of Tf higher than the Tf of the RE composition of the coiled molded body 6. New In order to maintain the semi-molten state for a long time, it is necessary to minimize the reaction with the support material 20 and to suppress the growth of crystals other than seed crystals. In the cooling process, the molded body 11 has a high Tf and thus crystallizes relatively quickly at an early stage of high temperature to prevent a reaction with the support material 20. Since the compact 10 has a low Tf, crystal growth from the compact 11 is prevented,

Seedin is performed above the Tf of the coiled compact 6 and below the Tf of the seed crystal. At this time, a larger seed crystal is more efficient and desirable. The molded body 9 may have the same RE composition as the coil-shaped molded body 6. The QMG crystal grown from the seed crystal crystallizes the compact 9 and further crystallizes the coil-like compact 6 to form a coil-like QMG crystal.

After the coil-shaped crystal is cooled to room temperature, it is sliced to a predetermined thickness by a diamond blade or the like. At this time, if there is an uncut portion 8 as shown in Fig. 6, the mechanical damage will not occur when slicing. Less. If there is no uncut portion, it is desirable to perform slicing after reinforcing the space between conductors with resin or the like.

 The advantage of the FG method is that coil processing is performed on a compact (compact), so that it does not require expensive processing equipment and can be easily manufactured using inexpensive tools. In addition, since it has a coil shape (panel shape) after crystal growth, mechanical strain is eased and cracks are difficult to enter.

 As described above, electrodes must be provided to energize the spiral superconductor produced by the GF method or the FG method. It is desirable that the contact resistance of the electrode be smaller. To give an example of electrode fabrication, an Ag base is applied to a predetermined position, and then the temperature is raised from 700 ° C to a temperature lower than the decomposition temperature of the superconductor, and then lowered. It is desirable for the efficiency of the process to gradually cool the oxygen enrichment treatment in an oxidizing atmosphere (preferably in pure oxygen) during this temperature drop. In this way, a spiral QMG superconducting coil with electrodes is obtained.

 Such spiral coils need to be mechanically reinforced in order to withstand the external force and the Mouth Lenz force in handling. For reinforcement, it is effective to connect adjacent conductors. As an example of reinforcement, it is desirable to use an adhesive with a small volume change during curing, such as a thermosetting resin, or a material with a coefficient of thermal expansion close to that of QMG materials. It is also desirable to fix (reinforce) the space between the eyebrows for the laminated magnets for the above reasons.

Also, in order to connect each layer with a superconductor, it is necessary to match the crystal orientation of each layer. The connection position is determined when the crystal orientations are almost aligned. The coil connection part 12 is processed as shown in Fig. 8 (A), and the molded body 13 with RE composition of Tf (Tf z) lower than Tf (Tf c) of the superconductor is formed in the recess 14 in the same figure. Arrange as shown in (A). This is heated to a temperature T (Tfc>T> Tfz) at which the molded body 13 is in a semi-molten state and the coil is not decomposed. Thereafter, as shown in FIG. 8 (B) and its partially enlarged view (C), crystals grow from the respective layers 12 and 12 facing each other by slow cooling near Tfz, and at the same time, crystals are formed. The crystals of the 123 phase of 13 grow, and these crystals combine to form a crystal 16 (the rest of the crystal growth is at the center in the figure), which becomes the superconductor 15, thereby connecting the multilayers You can coil.

 Further, similarly to the above, the superconductor which connects the start and the end of the coil formed by one or more layers of the spiral coil is formed by placing the molded body 13 in the recess in the conductor and heat-treating the same. Thus, a magnet having a closed loop of superconductivity, in which the connection of each layer and the start and end of the coil are connected by a superconductor, is obtained. Example

 Example 1

Each of the commercially available reagents having a purity of 99.9%, Y ₂ O ₃ , BaO ₂ , and CuO are converted to a metal element of Y: Ba: Cu having a molar ratio of 13:17:24 (ie, a molar ratio of 123 phase: 211 phase in the final structure) Was 7: 3). Further, 0.5% by weight of platinum was added. The mixed powder was calcined once at 800 ° C for 8 hours and further ground. The calcined pulverized powder was formed into a disk shape with a thickness of about 18 bands using a cylindrical mold with an inner diameter of 85 mm. In addition, Sm-based and Yb-based disc-shaped compacts with a thickness of 4 mm were prepared in the same manner as the Y-based compacts.

These Sm-based on the A 1 ₂ 0 ₃ support material, Yb system was arranged in overlapping furnace from below in the order of Y system. The temperature of these compacts was raised to 1150 in the atmosphere in 8 hours and maintained for 30 minutes, then lowered to 1030 in 1 hour and maintained for 1 hour. During this time, seeding was performed using Sm-based seed crystals (QMG crystals) that had been prepared in advance. The orientation of the seed crystal was set on the cleaved surface of the compact so that the c-axis would be normal to the disc-shaped compact. Then 1005-980 It was cooled to 100 ° C for 100 hours to grow Y-based QMG crystals. It was further cooled to room temperature over about 15 hours to obtain a cylindrical single crystal Y-based QMG crystal.

 By cutting (slicing) this crystal using a diamond blade, a disk-shaped QMG material with a thickness of 4.5 was obtained. This was fixed to an unglazed plate having a thickness of 8 mm with glue. Then, the nozzle of the water jet cutting is programmed in advance to move along the spiral contour shown in Fig. 1 (A), and the nozzle movement speed is set to about 50mmZmin. Then, the unglazed plates were spirally cut. At this time, a method called abrasion, in which garnet powder was ejected with water, was used.

 After vortexing, the coiled QMG material was removed from the unglazed plate by heating the glue. After the glue was sufficiently removed, Ag paste 18 was applied to both ends of coil 1 as shown in Fig. 9 (A) and (B), and further heated to 850 ° C. After holding at 850 ° C for 10 minutes, oxygen was then flowed into the furnace and cooled from 650 to 350 ° C over 50 hours to perform oxygen enrichment treatment. After cooling to room temperature, the resin was subjected to force as shown in FIGS. 9 (A) and (B) using epoxy resin 17 (trade name: Araldite).

 In this way, an eight-turn coil having a cross-sectional area of the conductor 1-1 of about 3.5 mm (width) × 4.5 IMI (thickness) was produced. Then, a copper current terminal was connected to the Ag electrode of the coil 1 using ultrasonic soldering. This was cooled to liquid nitrogen temperature (approximately 77K), and a current of 550 A was passed. As a result, a magnetic field of 0.85 kGauss was successfully generated at the center.

 Example 2

Commercially available 99.9% purity reagents of Y ₂ 0 _3, the Ba0 _2, CuO Y: Ba: molar ratio of metal elements of Cu 25: 35: 49 (i.e. 123 phase of the final structure: 211 phase molar ratio of Was 75:25). In addition, Rh 0.2 % By weight. The mixed powder was calcined once at 830 ° C for 8 hours and further ground. The calcined powder was formed into a disc with a thickness of about 25 dragons using a cylindrical mold with an inner diameter of 85. In addition, Sm-based and Dy- and Yb-based disc-shaped compacts with a thickness of 4 mm were prepared in the same manner as the Y-based compacts. Furthermore, the Y-based compact was pressed by an isotropic isostatic press. This Y-based compact was processed into a partially connected spiral shape as shown in Fig. 6 (A) and (B). This was done by first drilling a hole, and then drilling a hole into the hole to make a cut in a coil.

These compacts were placed in a 7 Sm based on the A 1 ₂ 0 ₃ support member 20 as shown in FIG, Yb-based, Y-based, overlapped furnace from below in the order of Dy system. At this time, a cut was made in the Yb-based molded body so that the atmosphere spread throughout the inside of the coil-shaped molded body (Y-based). The temperature of these compacts was raised to 1160 ° C in air for 8 hours and maintained for 40 minutes in the atmosphere, and then lowered to 1040 ° C for 1 hour and maintained for 1 hour. In the meantime, seeding was performed using Nd-based seed crystals (QMG crystals) prepared in advance. The orientation of the seed crystal was set on the cleaved surface of the compact so that the c-axis was normal to the disk-shaped compact. Thereafter, it was cooled to 1015 to 975 ° C over 150 hours to grow a Y-based coiled QMG crystal. It was further cooled to room temperature over about 15 hours.

 The crystal was cut (sliced) using a diamond blade to obtain a spiral QMG material with a thickness of about 4 mm. Further, as shown in Fig. 10, Ag paste 18 was applied to both ends of this material, heated to 880 ° C, and maintained at 880 ° C for 10 minutes.Oxygen was then flowed into the furnace at 650 ° C. To 350 ° C for 50 hours to perform oxygen enrichment treatment. After cooling to room temperature, it was reinforced with epoxy resin 17 as shown in FIG.

Thus, an eight-turn coil 1 in which the cross-sectional area of the conductor 11 was about 3.5 mm (width) × 4.0 mm (thickness) was produced. And of this coil A current terminal made of copper was connected to the Ag electrode using ultrasonic soldering. This was cooled to the temperature of liquid nitrogen (approximately 77 K), and when a current of 500 A was passed, a magnetic field of approximately 0.90 kGauss was successfully generated at the center.

 Example 3

 The same experiment was conducted by changing the RE composition, the addition conditions, the slow cooling conditions, and the coil thickness of the Y-based molded body of Example 1 as shown in Table 1. As shown in this table, the superconducting magnet of each RE composition generated a magnetic field almost equivalent to that of the Y system without quenching. -Table 1

実施例 4

Example 4

The experiment was repeated in the same manner as in Example 2 except that the RE composition of the Y-based compact of Example 2, the RE composition of compact 9 (see Fig. 7), the addition conditions, the slow cooling conditions, and the coil thickness were changed as shown in Table 2. went. As shown in this table, the superconducting magnet of each RE composition generated a magnetic field almost equivalent to that of the Y system without quenching. Table 2

 * See Fig. 7 Example 5

 As shown in FIG. 11 (before (A) lamination, after (B) lamination), four Y-system spiral coils produced in Example 2 were laminated. At this time, the coils 1 A and 1 C of the first and third layers are oriented from the center to the outside when the current flows clockwise when viewed from above, and the second and fourth layers The coils 1B and 1D were laminated from the outside toward the center. Then, the electrode 21 A at the center of the coil 1 A of the first layer and the electrode 21 B at the center of the coil 1 B of the second layer are soldered with a low melting point solder (trade name: Cerasolzer 1). Connected by iron. Similarly, the outer electrode 21 B—1 of the second-layer coil 1 B and the outer electrode 21 C of the third-layer coil 1 C are connected to the inner electrode 21 C—of the third-layer coil 1 C. The first and fourth layers were connected to the electrode 21D inside the coil 1D. Electrodes were provided outside the first and fourth layers, and these electrodes were connected to the current leads of the DC power supply. Furthermore, the layers were fixed with epoxy resin.

The four-layer magnet was immersed in liquid nitrogen. After the magnet was sufficiently cooled to 77 K, 500 A was supplied. Although the nitrogen boil grew somewhat larger at the electrode part between the layers, the magnet was on the axis as shown in the graph of Fig. 12. Such a magnetic field distribution was generated.

 Example 6

 The four-layer magnet prepared in Example 5 was placed in an external magnetic field of 10 kGauss, and liquid nitrogen was introduced and cooled to 77 K. Then, electricity was supplied so that a magnetic field was generated in the same direction as the external magnetic field. At this time, a part of the superconductor was burned when 245 A was applied. The burned part was the conductor of the second turn from the center of the second layer, and the superconducting phase (123 phase) of this conductor was completely decomposed by heat.

 Therefore, as shown in Fig. 13, the shape of the spiral was 5 mm for the center of the conductor, 4.5 mm for the middle, and 4 mm for the outer periphery, and the other conditions were the same as in Example 2. A coil 1 was prepared. At this time, the thickness of Koinore 1 was set to 4 mm and 3.5 mm. The first and fourth layers were 3.5 mm thick, and the second and third layers were 4 mm thick. Four layers were connected and reinforced as in Example 5.

 The four-layer magnet was placed in an external magnetic field of 10 kGauss, and liquid nitrogen was injected and cooled to 77 K. Then, current was supplied so that a magnetic field was generated in the same direction as the external magnetic field. At this time, a current of 400 A was applied, and 13.8 kGauss was recorded at the center together with the external magnetic field. From this, it was found that the magnetic force cross-sectional area of the conductor 1 _ 1 having a larger cross-sectional area at the center was superior to that of the same conductor.

 Example Ί

A Y-type spiral coil produced in the same manner as in Example 2 except that the electrode production process using Ag paste and the reinforcing process using epoxy resin were omitted was provided with a 0.2 mm thick Pt spacer. Four layers were stacked in the same manner as shown in Fig. 11 (B). At this time, the coils 1A and 1C of the first and third layers are oriented so that they flow outward from the center when the current 2 flows clockwise when viewed from above. In coil 1 B, ID The layers were stacked so that the current flowed from the outside toward the center. Then, the end of the center of the first eyebrow and the end of the center of the second layer were processed as shown in FIG. 14, and a Yb-based molded body 13 was arranged. Similarly, the same addition and Yb-based molded body are arranged between the outer edge of the second eyebrow and the outer edge of the third layer, and between the inner edge of the third eyebrow and the inner edge of the fourth eyebrow. Was. Ag paste was applied to the outer edges of the first and fourth layers.

 The coil and the compact thus laminated were placed in a furnace and heated to 960 ° C in air for 8 hours. After being kept at this temperature for 5 minutes, it was cooled to 930 ° C in 2 hours and further cooled to 870 ° C for 120 hours. The sample was further cooled in an oxygen stream from 700 ° C to 350 ° C over 60 hours, and then cooled to room temperature. After being carefully removed from the furnace, epoxy resin was applied between the conductors and part of the interlayer for hardening. After sufficient curing, the Pt plate of the spacer was extracted. The current leads of the DC power supply were connected to the outer Ag electrodes of the first and fourth layers using low melting point solder.

 The four-layer magnet was immersed in liquid nitrogen. After the magnet was sufficiently cooled to 77 K, a current of 500 A was applied. There was almost no change in the boiling of nitrogen at the connection between the layers. The magnet generated a magnetic field distribution on the axis as shown in Fig. 15.

 Example 8

A Y-type spiral coil and a plate-like Y-type QMG material manufactured in the same manner as in Example 2 except that the electrode manufacturing process using Ag paste and the reinforcing process using epoxy resin were omitted as shown in Fig. 16 Four Pt spacers having a thickness of 0.2 mm were arranged between the layers and laminated. At this time, the coils 1 A and 1 C of the first and third layers are oriented so that they flow outward from the center when current flows clockwise when viewed from above, and the coils 1 B and 4 B of the second and fourth eyebrows , ID are stacked so that the current flows from the outside to the center. And the center of the first layer The end of the part and the end of the center of the second eyebrow were processed in the same manner as in FIG. 14 described above, and a Yb-based formed body was arranged. In the same manner, the same processing and arrangement of the Yb-based compact are performed between the outer edge of the second layer and the outer edge of the third eyebrow, and between the inner edge of the third layer and the inner edge of the fourth layer. Was done.

 Also, as shown in FIGS. 16 and 17, similar depressions are formed at the outer ends of the first and fourth layers and the upper and lower ends of the plate-shaped QMG material 19 corresponding to these ends. Processing 14 is provided, respectively, and Yb-based molded body 13 is arranged. Tenths: 'At this time, the crystal orientation of the plate-shaped QMG material 19 is almost the same as that of the QMG coils 1A and 1D on the first and fourth eyebrows Was placed. Ag paste 18 was applied to the outer ends of the first and fourth layer coils.

 The coil and the compact thus laminated were placed in a furnace and heated to 960 ° C in air for 8 hours. After being kept at this temperature for 5 minutes, it was cooled down to 930 ° C in 2 hours and further cooled down to 870 ° C in 120 hours. After cooling in an oxygen stream from 700 to 350 ° C over 60 hours, it was cooled to room temperature. After being carefully removed from the furnace, epoxy resin was applied between the conductors and part of the interlayer for hardening. After sufficient curing, the Pt plate of the spacer was pulled out. A manganin wire was wound 50 times as a heating element around the connected plate-shaped QMG material and fixed with epoxy resin to produce a superconducting switch. The current leads of the DC power supply were applied to the Ag electrodes outside the first and fourth layers using low-temperature solder.

The four-layer magnet was immersed in liquid nitrogen, the magnet was sufficiently cooled down to 77 K, 8 A was supplied to the manganin wire to make it partially normal, and then 500 A was supplied to the magnet. After that, the power supply to the manganin wire was stopped, and the power supply to the magnet was reduced to 100 AZ min to zero. Approximately 30 seconds after the current was reduced to zero, the magnet generated a magnetic field distribution on the axis as shown in Fig. 18. This confirms operation in persistent current mode. Industrial availability

 As described in detail above, the present invention enables a high-quality oxide superconducting magnet, can be applied to various fields, and has a very large industrial effect. Specific examples include various magnets for experiments, magnets for excitation in a motor, magnets for accelerators, magnets for nuclear magnetic resonance, and the like.

Claims

The scope of the claims 1. Single crystal REBa ₂ Cu ₃ 0 ₇ - _x phase (RE is a rare earth element containing Y and a combination thereof) RE ₂ BaCu 0 ₅ has a finely dispersed structure and has a spiral coil shape A superconducting magnet characterized in that: 2. REBa ₂ Cu ₃ 0 direction of the c-axis of the crystal orientation of the _7-phase cage two assortment connexion within 40 degrees, and the range first claim to feature in that it contains a least one well of Pt or Rh traces Superconducting magnet according to the item. 3. The claim 1 or 2, wherein the c-axis of the crystal orientation of the REBa ₂ Cu ₃₀ phase is aligned within 20 degrees with respect to the normal of the plane constituting the spiral. Superconducting magnet.  4. Claims 1, 2 or 3 characterized in that the cross-sectional area of the conductor inside the spiral is larger than the cross-sectional area of the outer conductor Superconducting magnet.  5. The resin according to claim 1, wherein a resin is present in at least a part of a gap between the superconductors constituting the spiral, and the space between the conductors of the spiral is reinforced. The superconducting magnet described in Crab.  6. A superconducting magnet, wherein a plurality of spiral coils according to any one of claims 1 to 5 are stacked.  7. The superconducting magnet according to claim 6, wherein spiral directions (right-handed or left-handed) of adjacent layers are alternately arranged.  8. The superconducting magnet according to claim 6, wherein ends of each of the stacked spiral coils are connected by a metal having a high electrical conductivity. . 9. stacked respectively between the ends of the spiral coils of the coil conductor Tf - REBa ₂ Cu ₃ 0 ₇ having a lower Tf than (REBa ₂ Cu ₃ 0 ₇ generation temperature of the phase) The superconducting magnet according to claim 6 or 7, wherein the superconducting magnets are connected by a superconductor composed of phases.  10. The method according to any one of claims 6 to 9, wherein, of the plurality of spiral coils, the thickness of the central spiral coil is greater than the thickness of the spiral coils at both ends. Superconducting magnet according to any of the above.  11. A resin according to any one of claims 6 to 10, wherein a resin is present in at least a part between layers of each spiral coil, and each coil is reinforced. Superconducting magnet. 12. Claims Section 1 to 11 either beginning and the end of the single-crystal-like coil formed by spiral coils of one layer or a plurality of several layers according to in Section REBa ₂ Cu ₃ 0 ₇ - closed circuit comprising a superconductor constituted by a connecting child using an oxide superconducting material that have a tissue RE ₂ BaCu0 ₅ is finely dispersed in the _x phase, the current introducing terminal and the superconducting sweep rate pitch Superconducting magnet characterized by becoming. 13. Single crystalline _{REBa 2 Cu 3 0 7 - RE} 2 BaCu0 5 in _x phase is cut out of the plate-like material from the oxide superconductor having a weave set finely dispersed, then spiral the plate-like material A method for manufacturing a superconducting magnet, characterized in that the material is processed into a spiral coil by making a cut in a shape.  14. The manufacturing of a superconducting magnet according to claim 13, wherein the plate-like material is fixed to the support base with an adhesive, and then subjected to spiral processing by water jet cutting. Method. 15. A compact is manufactured from a powder containing oxides of RE, Ba, and Cu. The compact is processed into a spiral coil shape, and then heated to a semi-molten state consisting of 211 phases and a liquid phase. , followed by slow cooling in an oxidizing atmosphere single crystalline REBa ₂ Cu ₃ 0 ₇ - wherein that you RE ₂ BaCu0 ₅ in _x phase is allowed to form a superconducting material that have a finely dispersed organizations Manufacturing method for superconducting magnets. 16. Place the compact on the spiral compact so as to cover the spiral compact, heat them to a semi-molten state consisting of 211 phase and liquid phase, and then control the crystal orientation by the seed crystal 16. The method for producing a superconducting magnet according to claim 15, wherein the method is gradually cooled in an oxidizing atmosphere.  17. Spiral coils produced by the method according to any one of claims 13 to 16 are laminated so that the spiral direction (right-handed or left-handed) is alternated, and each coil is electrically connected. A method for manufacturing a superconducting magnet, characterized in that it is electrically connected. 18. As a whole laminated coil is a superconductor, each spiral of a material consisting of REBa ₂ Cu ₃ 0 ₇ _ _x phase is superconducting phase having a low Tf Ri by Tf spiral Koi Le conductor The method for manufacturing a superconducting magnet according to claim 17, wherein the ends of the coil are connected. 19. Claims paragraph 13, second 18 RE ₂ BaCu0s the beginning and end of Koiru which is Yotsute formed with the method described in ₃ 0? I phase single crystalline REBa ₂ Cu to any of term is A method for producing a superconducting magnet, characterized in that the connection is made with a superconducting material having a finely dispersed structure.