JP5118990B2 - Superconducting tape wire and defect repair method - Google Patents

Description

  The present invention relates to a superconducting tape wire for manufacturing a superconducting coil used in various devices such as a superconducting power storage device, a magnetic resonance imaging apparatus, a nuclear magnetic resonance apparatus, and a magnetic levitation apparatus, and a defect repair method.

The superconducting tape wire used for the superconducting coil is obtained by bonding an intermediate layer made of, for example, cesium oxide (CeO ₂ ) to one side of a tape-like substrate formed of a material having excellent heat resistance such as Hastelloy or stainless steel. For example, an yttrium superconducting layer is formed on the surface of the intermediate layer by vapor deposition or the like, and a copper stabilization layer, for example, is bonded to the surface of the superconducting layer with, for example, a protective layer made of silver by solder or the like. Manufactured. This stabilization layer protects the superconducting layer by bypassing current to the stabilizing layer when the temperature rises due to some factor during operation of the superconducting coil and the electrical resistance of the superconducting layer increases.

  In the production of the superconducting tape wire, a defect portion (low characteristic portion) having a low critical current value may be generated in a part of the superconducting layer due to a void, an impurity, or a deviation in crystal orientation due to some factor. FIG. 7 shows the measurement result of the critical current value at each part of the tape wire, with the horizontal axis representing the length of the superconducting tape wire and the vertical axis representing the critical current value. As shown in this graph, it can be seen that the majority of the portion has a critical current value of, for example, 150 A, but there is a 40 A defect portion with a low critical current value in the vicinity of 100 m. When the above-mentioned defective portion is formed on a part of the superconducting tape wire, the allowable current value that can be passed through the superconducting coil formed by winding the superconducting tape wire around the outer peripheral surface of the core is governed by the defective portion, It cannot be energized to a high current.

  In addition, since the intensity of the magnetic field generated in the superconducting coil is strong on the center side of the coil and weak on the outer peripheral side, the critical current value varies depending on the coil portion. It is difficult to set the position of the defective portion of the tape wire when the coil is manufactured to a location where the critical current value is difficult to decrease, and the allowable current value of the superconducting coil varies depending on the position of the defective portion. For this reason, the random defect makes the design work of the superconducting coil difficult. In particular, when producing a long tape wire, the longer the length, the more likely the defect portion is included, and it is difficult to manufacture a superconducting coil using the long tape wire.

In order to solve the above problem, Patent Literature 1 discloses a superconducting defect repairing method. In this repair method, after removing a defective portion of a superconducting layer bonded to one surface of a metal substrate via a noble metal layer, a superconducting defect repairing composition is formed on the defective portion of the superconducting layer to obtain a molded body. Thereafter, the defective part is repaired by firing the molded body at a temperature equal to or higher than the partial melting point of the defect repairing composition and lower than the firing temperature for forming the superconducting layer.
Japanese Patent Laid-Open No. 5-294630

  However, the above-described conventional method for repairing a defective portion of a superconducting layer includes an operation of removing the defective portion of the superconducting layer, and an operation of forming a superconducting defect repairing composition in a recess formed in the defective portion to obtain a molded body. Since the molded body is required to be fired, there is a problem that the repair work of the defective portion is very troublesome. In addition, a dedicated superconducting defect repair composition must be newly prepared, and there is a problem in that the cost of the repair material cannot be reduced.

  The present invention provides a superconducting tape wire and a method for repairing a defective portion that can solve the above-described problems in the prior art and can easily repair the defective portion of the superconducting layer of the superconducting tape wire at a low cost. There is to do.

In order to solve the above problems, the invention according to claim 1, corresponds to the defective portion generated in the superconducting layer of the superconducting tape wire forming the superconducting layer on one side of the tape-shaped substrate, the superconducting layer The repair superconducting layer of the repair superconducting tape wire cut to a predetermined length by forming a repair superconducting layer on one side of the tape-shaped repair substrate is soldered to the stabilization layer formed on the surface of The gist is that they are bonded.

According to a second aspect of the present invention, there is provided a method of repairing a defect portion of the superconducting layer of a superconducting tape wire material having a superconducting layer formed on one side of a tape-like substrate, wherein the superconductivity corresponds to the defect portion generated in the superconducting layer. For the stabilization layer formed on the surface of the layer , a repair superconducting tape wire formed by forming a repair superconducting layer on one side of the tape-shaped repair substrate is cut to a predetermined length, and the repaired superconductivity is cut. The gist is to bond the superconducting layer for repair of the tape wire using solder .

The invention according to claim 3 is the length of the superconducting tape wire for repair cut to the predetermined length in claim 2, the length dimension of the repair substrate is set to 40 cm to 100 cm, The gist is that the thickness of the substrate of the superconducting tape wire is set to be thinner than the thickness of the substrate .

The invention according to claim 4, in claim 2, the surface of the superconducting layer is summarized as Kotokoto said stabilizing layer by solder is adhered.

According to a fifth aspect of the present invention, in the third aspect, a stabilizing layer is formed on a surface of the repairing superconducting tape wire of the repairing superconducting tape wire, and the stabilizing layer is used as the stabilizing layer of the superconducting tape wire. The gist is to adhere to.

The invention according to claim 6 is the invention according to claim 5, wherein the stabilization layer is bonded to a surface of the repair superconducting layer of the repair superconducting tape wire by solder, and the stabilization layer is bonded to the superconducting tape wire. The gist is to adhere to the stabilizing layer with the same solder as the solder.

The invention according to claim 7 is the invention according to any one of claims 2 to 6 , wherein the superconducting tape wire for repair is bonded to the superconducting tape wire by winding the superconducting tape wire around a winding core. The gist of the present invention is that the superconducting tape wire is wound in an arc shape in the course of producing the superconducting coil.

The gist of an eighth aspect of the present invention is that, in any one of the second to seventh aspects, the superconducting tape wire for repair is bonded to a superconducting tape wire that is less than one turn of the superconducting coil.

According to the present invention, the superconducting tape wire for repair is cut to a predetermined length and bonded using solder to the stabilization layer formed on the surface of the superconducting layer corresponding to the defective portion of the superconducting layer of the superconducting tape wire. Therefore, the repair work of the defective portion of the superconducting layer can be easily performed. In addition, the strength of the superconducting tape wire can be prevented from being lowered as compared with the repair method in which the defective portion of the superconducting tape wire is excised and then connected. In addition, the superconducting tape wire for repair can be used as a tape wire without a stabilization layer obtained in the process of manufacturing the superconducting tape wire to be repaired, or a tape wire with a stabilization layer can be used. The cost of the material can be reduced.

Hereinafter, an embodiment of a method for repairing a defective portion of a superconducting layer of a superconducting tape wire embodying the present invention will be described with reference to FIGS.
First, the structure of the superconducting tape wire 11 will be described with reference to FIGS. 1 and 2.

The tape-shaped substrate 12 constituting the superconducting tape wire 11 is formed of Hastelloy having excellent tensile strength. A first intermediate layer 13 made of Gd ₂ —Zr ₂ —O ₇ is formed on one surface of the substrate 12 by a vapor phase method such as an ion beam assisted vapor deposition method. A second intermediate layer 14 made of cesium oxide (CeO ₂ ) is formed on the surface of the first intermediate layer 13 by a PLD (Pulse Laser Deposition) vapor deposition method or an EB (Electron Beam) vapor deposition method. A superconducting layer 15 is formed on the surface of the second intermediate layer 14 by a CVD (Chemical Vapor Deposition) vapor deposition method, a PLD vapor deposition method or a MOD (Metal-organic deposition) vapor deposition method. As the material of the superconducting layer 15, there is a yttrium-based (Y, Gd, etc.) by _Y 1 _-Ba 2 _-Cu 3 -O _x system or the like. They develop superconducting properties by heat treatment at 400-1000 ° C. Further, a protective layer 16 made of silver which also functions as a stabilizing layer is formed on the surface of the superconducting layer 15 by vapor deposition. In this embodiment, a stabilization layer 17 made of copper is bonded to the surface of the protective layer 16 by solder 18 containing Ag.

  In this embodiment, the width dimension of the superconducting tape wire 11 is 10 mm. The thickness dimensions of the substrate 12, the first intermediate layer 13, the second intermediate layer 14, the superconducting layer 15, the protective layer 16 and the stabilizing layer 17 are sequentially set to 50 to 100 μm, 0.5 to 1 μm,. 5 to 1 μm, 1 to 2 μm, 3 to 5 μm, and 50 to 200 μm.

  Next, the surface of the stabilization layer 17 of the superconducting tape wire 11 is partially bonded so as to correspond to the defect portion K partially formed in the superconducting layer 15 to repair the defect portion K. The structure of the superconducting tape wire 21 for repair to be performed will be described.

As shown in FIG. 1, a tape-like repair substrate 22 constituting the repair superconducting tape wire 21 is formed of, for example, hastelloy having a high tensile strength. A first intermediate layer 23 made of Gd ₂ —Zr ₂ —O ₇ is formed on one surface of the repair substrate 22 by the vapor phase method described above. A second intermediate layer 24 made of cesium oxide (CeO ₂ ) is formed on the surface of the first intermediate layer 23 by the CVD method described above. A repair superconducting layer 25 is formed on the surface of the second intermediate layer 24 by the vapor phase method described above. The material of the superconducting layer 25 for repair is the same as the material of the superconducting layer 15 described above. Further, a protective layer 26 made of silver is formed on the surface of the superconducting layer 25 by the vapor phase method described above.

  The superconducting tape wire for repair 21 configured as described above is configured similarly to the configuration in which the stabilization layer 17 of the superconducting tape wire 11 is omitted. Furthermore, the different configurations of both tape wires 11 and 21 are such that the thickness of the repair substrate 22 is thinner than the thickness (70 to 100 μm) of the substrate 12 of the superconducting tape wire 11, for example, 30 to 50 μm. It is a set point.

Next, repair work of the defect portion K generated in a part of the superconducting layer 15 of the superconducting tape wire 11 configured as described above will be described.
First, the repair superconducting tape wire 21 having a long dimension shown in FIG. 1 is cut into a predetermined length necessary for repairing the defective portion K of the superconducting tape wire 11 as indicated by a chain line. Next, as shown in FIG. 2, solder H impregnated with a high content of silver is applied to the upper surface of the stabilization layer 17 of the superconducting tape wire 11 so as to correspond to the defect portion K generated in the superconducting layer 15. Then, the superconducting tape wire 21 for repair cut by the solder H is bonded so that the protective layer 26 corresponds to the stabilizing layer 17. Then, the surface of the protective layer 26 of the superconducting tape wire 21 for repair is joined to the upper surface of the stabilizing layer 17 of the superconducting tape wire 11 by heating the solder H to 140 ° C., for example, and the repair of the defective portion K is completed. To do. The stabilizing layer 17 is bonded to the protective layer 16 by solder 18, and the solder 18 and the solder H are set to the same component.

  In this specification, “corresponding to the defect K generated in the superconducting layer 15” means that the repairing superconducting tape wire 21 starts in the longitudinal direction of the superconducting tape wire 11 starting from the defect K as shown in FIG. Means a state in which only predetermined lengths L1 and L2 are adhered to each other.

  Superconducting tape wire 11 in which defective portion K of superconducting layer 15 is repaired is once wound around a bobbin (not shown). FIG. 4 shows a superconducting coil manufactured by winding a superconducting tape wire 11 that has been repaired for a defective portion K by a superconducting tape wire 21 for repair around a core 33 connected to a coil substrate 32 of a winding frame 31. Indicates. The winding frame 31 is provided with electrode terminals 34 and 35 for connecting the starting end and the terminal end of the superconducting tape wire 11.

  When the superconducting tape wire 11 having repaired the defective portion K by the repairing superconducting tape wire 21 is supplied with a current in the right direction, for example, to the superconducting layer 15 of the superconducting tape wire 11 as shown in FIG. With respect to the direction of the current of the defective portion K, current flows from the superconducting layer 15 on the upstream side to the superconducting layer 25 of the superconducting tape wire 21 for repair as indicated by the arrow, and from the superconducting layer 25 to the superconducting layer 15 of the superconducting tape wire 11 again. Flowing. For this reason, since the current supplied to the superconducting layer 15 of the superconducting tape wire 11 flows around the defect portion K, the current is prevented from concentrating on the defect portion K having a large electric resistance and being abnormally heated. be able to.

  The length dimension (L1 + L2) of the superconducting tape wire for repair 21 cut to a predetermined length is set to 40 cm to 100 cm, for example. When this dimension (L1 + L2) is short, the energization paths of the protective layer 16, the stabilization layer 17 and the protective layer 26 between the superconducting layer 15 of the superconducting tape wire 11 and the superconducting layer 25 of the superconducting tape wire 21 for repairing. For example, when the width dimension of the tape wire 11 is 10 mm, 40 cm or more is desirable.

According to the repair method of the defective portion K of the superconducting tape wire 11 of the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the surface of the protective layer 26 of the superconducting tape wire 21 for repair is heat bonded to the surface of the stabilizing layer 17 of the superconducting tape wire 11 with solder H, and the superconducting layer of the superconducting tape wire 11 The repair work of the defective portion K generated in a part of 15 was performed. Therefore, the defect K is repaired by cutting the repairing superconducting tape wire 21 and heating and bonding the cut repairing superconducting tape wire 21 to the upper surface of the stabilizing layer 17 of the superconducting tape wire 11 with solder H. Can be easily performed.

  (2) In the above embodiment, since the superconducting tape wire 21 for repair has a configuration in which the stabilization layer 17 of the superconducting tape wire 11 is omitted, the tape wire 21 is easily manufactured to produce a repair composition. Compared with the conventional technique, the cost of the repair material can be reduced.

  (3) In the above embodiment, the thickness dimension of the repair substrate 22 of the repair superconducting tape wire 21 is set to be thinner than the thickness dimension of the substrate 12 of the superconducting tape wire 11. The overall wall thickness can be kept thin. Therefore, as shown in FIG. 4, when a superconducting coil is manufactured by winding the superconducting tape wire 11 around the core 33 of the winding frame 31, the superconducting wire is wound so as to be in contact with the repair substrate 22 of the superconducting tape wire 21. The bending strains of the two bent portions of the tape wire 11 can be alleviated, and the allowable current value of the superconducting coil can be prevented from decreasing.

  (4) In the above embodiment, the solder 18 for bonding the protective layer 16 and the stabilizing layer 17 and the solder H for bonding the stabilizing layer 17 and the protective layer 26 are set to the same component. The adhesion state can be the same. As a result, when a superconducting coil is manufactured, when bending is applied, the adhesion state of each layer can be stably and properly maintained, and when used as a superconducting coil, the protective layer 16 and the stabilizing layer are changed due to temperature changes. When compressive stress or tensile stress is applied to the protective layer 17 and the protective layer 26, the bonding state of each layer can be properly maintained.

In addition, you may change the said embodiment as follows.
As shown in FIG. 5, as the superconducting tape wire 21 for repair, a surface in which a stabilizing layer 27 similar to the stabilizing layer 17 of the superconducting tape wire 11 is bonded to the surface of the protective layer 26 with solder 28 is used. May be. In this configuration, the structure of the superconducting tape wire 21 for repair can be made exactly the same as the structure of the superconducting tape wire 11. In this case, the superconducting tape wire 11 itself can be cut into a predetermined length and used as the superconducting tape wire 21 for repair. Therefore, it is not necessary to manufacture the dedicated superconducting tape wire 21 for repair, and the cost of the repair material can be further reduced.

  As shown in FIG. 6A, a superconducting tape in which the substrate 12 of the superconducting tape wire 11 is formed of a conductive material such as copper or silver, and the first and second intermediate layers 13 and 14 are omitted. The wire 11 is manufactured. The stabilization layer 27 of the superconducting tape wire 21 for repair may be bonded to the surface of the substrate 12 of the superconducting tape wire 11 with solder H. Further, as shown in FIG. 5B, the repair superconducting layer 25 of the repairing superconducting tape wire 21 without the stabilization layer 27 may be bonded to the substrate 12 of the superconducting tape wire 11 by solder H. The protective layer 26 may be omitted in FIG.

In each of the above embodiments, the superconducting tape wire 21 for repair can be bonded from both the upper and lower surfaces of the superconducting tape wire 11, and the repair work can be easily performed.
The repair substrate 22 of the superconducting tape wire 21 for repair shown in FIGS. 1 and 2 may be set to the same thickness as the substrate 12 of the superconducting tape wire 11. In this case, in the manufacturing process of the superconducting tape wire 11, the superconducting tape wire in a state where the stabilization layer 17 is not adhered can be used as the repairing superconducting tape wire 21. Manufacturing is easy and the cost of repair materials can be reduced.

  Since the superconducting tape wire 21 for repair only has to have a function for repair, in order to make the superconducting coil shown in FIG. For example, a material such as Cu or Ag other than Hastelloy may be used.

  -As the superconducting layer 25 for repairing the superconducting tape wire 21 for repairing, a superconducting layer 25 for repairing which has a larger thickness than the superconducting layer 15 of the superconducting tape wire 11 and a high maximum current value may be used. . In this case, the current cross-sectional area of the current can be set large by the superconducting layer 25 for repair, and the decrease in current density in the defective portion K caused by the defective portion K of the superconducting layer 15 can be easily compensated. Can do.

  -The superconducting tape wire 21 for repair is arranged so as to correspond to the defective portion K of the superconducting tape wire 11 in the course of manufacturing by winding the superconducting tape wire 11 in a coil shape around the core 33 of the winding frame 31 shown in FIG. You may make it adhere | attach. In this case, after bonding the superconducting tape wire 21 for repair in a state where the superconducting tape wire 11 is held in a straight line, it is possible to eliminate the stress strain generated at the joint portion between the two tape wires when forming the superconducting coil. So desirable.

  The repair superconducting tape wire 21 may be slightly wound around the superconducting tape wire 11 for one turn of the superconducting coil shown in FIG. In this case, since the current-carrying area between the superconducting layer 15 of the superconducting tape wire 11 and the superconducting layer 25 of the superconducting tape wire 21 for repair is increased and the electric resistance is lowered, the allowable current value of the coil can be improved. .

  As the material of the substrate 12 of the superconducting tape wire 11 and the material of the repairing substrate 22 of the superconducting tape wire 21 for repair, for example, one of a group such as stainless steel and nickel / tungsten alloy may be selected.

-You may make it repair the defect part K of the superconducting layer 15 of the superconducting tape wire 11 which abbreviate | omitted the stabilization layer 17 of the said superconducting tape wire 11. FIG.
The intermediate layer of the superconducting tape wire 11 may have a three-layer structure, or one in which at least one of the first intermediate layer 13 and the second intermediate layer 14 is omitted may be used.

  -You may use what omitted at least any one of the 1st intermediate | middle layer 23 and the 2nd intermediate | middle layer 24 of the said superconducting tape wire 21 for a repair.

The perspective view of the superconducting tape wire for repair used for repairing the defective part of the superconducting tape wire and superconducting layer of this invention. The longitudinal cross-sectional view which shows the state which cut | disconnected the superconducting tape wire for repair to predetermined length, and repaired the defective part of the superconducting layer of the superconducting tape wire. FIG. 1 is a sectional view taken along line 1-1 of FIG. The front view of the superconducting coil manufactured with the superconducting tape wire. The longitudinal cross-sectional view which shows the state which repaired the defect part of the superconducting layer of the superconducting tape wire of another embodiment of this invention. (A) And (b) is a longitudinal cross-sectional view which shows the state which repaired the defect part of the superconducting layer of the superconducting tape wire of another embodiment of this invention. The graph which shows the measurement result of the length and critical current value of a superconducting tape wire.

Explanation of symbols

  H, 18, 28 ... solder, K ... defective portion, 11, 21 ... superconducting tape wire, 12 ... substrate, 15, 25 ... superconducting layer, 17, 27 ... stabilization layer, 21 ... superconducting tape wire for repair, 22 ... Repair substrate, 25 ... superconducting layer for repair, 31 ... reel, 33 ... core.

Claims (8)

Corresponding to the defect generated in the superconducting layer of the superconducting tape wire material having a superconducting layer formed on one side of the tape-like substrate, the tape-shaped repair substrate is formed on the surface of the superconducting layer. A superconducting tape wire comprising a repairing superconducting tape wire cut to a predetermined length formed by forming a repairing superconducting layer on one side and bonded to the repairing superconducting layer with solder. In the repair method of the defective portion of the superconducting layer of the superconducting tape wire material in which the superconducting layer is formed on one side of the tape-shaped substrate
A repairing superconducting tape wire comprising a repairing superconducting layer formed on one side of a tape-like repairing substrate with respect to the stabilization layer formed on the surface of the superconducting layer corresponding to the defect generated in the superconducting layer. A method of repairing a defective portion of a superconducting tape wire, characterized in that the repaired superconducting layer of the repaired superconducting tape wire is cut to a predetermined length and bonded using solder. In Claim 2, the length dimension of the superconducting tape wire for repair cut into the predetermined length is set to 40 cm to 100 cm, and the thickness dimension of the repairing substrate is the thickness of the substrate of the superconducting tape wire material. A method of repairing a defective portion of a superconducting tape wire characterized by being set thinner than a dimension. 3. The method of repairing a defective portion of a superconducting tape wire according to claim 2, wherein the stabilization layer is bonded to the surface of the superconducting layer by solder. 4. The superconductivity according to claim 3, wherein a stabilization layer is formed on a surface of the repair superconducting layer of the repair superconducting tape wire, and the stabilization layer is bonded to the stabilization layer of the superconducting tape wire. Repair method for defective part of tape wire. 6. The surface of the repair superconducting layer of the repair superconducting tape wire according to claim 5, wherein the stabilizing layer is bonded to the surface of the superconducting tape wire by solder, and the stabilizing layer is attached to the stabilizing layer of the superconducting tape wire as the solder. A method for repairing a defective portion of a superconducting tape wire, characterized in that bonding is performed by the method described above. In any one of Claims 2-6, the adhesion | attachment of the superconducting tape wire for repair with respect to the said superconducting tape wire is in the middle of the process of winding the said superconducting tape wire around the core of a winding frame, and creating a superconducting coil. A method for repairing a defective portion of a superconducting tape wire, wherein the superconducting tape wire is wound in an arc shape. 8. The repair method for a defective portion of a superconducting tape wire according to any one of claims 2 to 7, wherein the superconducting tape wire for repair is bonded to a superconducting tape wire that is less than one turn of a superconducting coil.

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