JP2015204338A - Superconducting current lead and method of manufacturing superconducting current lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable superconducting current lead having high connection strength and stabilized superconducting characteristics, which can be obtained stably by reducing the connection resistance.SOLUTION: A superconducting current lead 10 includes a tape-like superconducting wire rod 11 where an intermediate layer 112, a superconducting layer 113, and a stabilization layer 114 are laminated, in order, on a metal substrate 111, first and second electrodes 12-1, 12-2 being bonded to the opposite ends of the superconducting wire rod 11, and a cylindrical reinforcement member 14 for housing a lead body including the superconducting wire rod 11 and the first and second electrodes 12-1, 12-2 while positioning so that a predetermined distance between electrodes can be obtained. The electrodes 12-1, 12-2 consist of a plurality of split bodies 122, 124, and the end of the superconducting wire rod 11 is sandwiched by the joint surfaces 122a, 124a of these split bodies 122, 124 and bonded to the superconducting wire rod 11.

Description

  The present invention relates to a superconducting current lead using an oxide superconducting wire, and more particularly to a superconducting current lead constituted by containing a superconducting wire and a metal electrode in a reinforcing member, and a method for manufacturing the same.

  In recent years, superconducting devices using superconductivity, such as superconducting cables and superconducting magnets, have been researched and developed for practical use. In general, a superconducting application device is installed in a low temperature part (low temperature container) and connected to an external device (for example, a power source) installed in a normal temperature part via a current lead.

  Since the operation of superconducting equipment is performed in a cryogenic environment, the heat insulation of the low temperature part is extremely important. If the heat insulation property of the low temperature part is poor and the heat penetration into the low temperature part is large, the cooling efficiency of the superconducting application equipment will decrease and the cooling cost for maintaining the superconducting state will increase. This is because it becomes impossible to drive. As a path of heat penetration into the low temperature part, a path for transferring heat through the low temperature container and a path for transferring heat through the current leads are conceivable.

  As a technique for preventing heat intrusion through a cryogenic vessel, a dual-structure cryogenic vessel having a refrigerant tank containing a refrigerant such as liquid nitrogen and a superconducting application device and a vacuum tank provided outside the refrigerant vessel It has been known. According to this low-temperature container, heat penetration into the low-temperature part is reduced by vacuum insulation.

  As a technique for preventing heat intrusion through the current lead, a superconducting current lead using an oxide superconductor has been proposed. An oxide superconductor has zero electrical resistance and low thermal conductivity below the liquid nitrogen temperature (one tenth of copper). Therefore, in the superconducting current lead, Joule heat is not generated during energization, and the amount of heat transferred to the low temperature portion is extremely small. Therefore, according to the superconducting current lead, heat penetration into the low temperature portion is reduced.

  A conventional superconducting current lead 50 is shown in FIG. FIG. 1A is an overall view of a superconducting current lead 50. FIG. 1B is a cross-sectional view taken along the line II in FIG. 1A.

  As shown in FIG. 1A, a superconducting current lead 50 includes a tape-shaped superconducting wire 51, a first metal electrode 52 disposed at one end (high temperature side) of the superconducting wire 51, and the other end of the superconducting wire 51. A second metal electrode 53 is provided on the (low temperature side). As shown in FIG. 1B, the first metal electrode 52 has a recess 521 into which the superconducting wire 51 is inserted.

  In general, since the connection work is easy and good electrical characteristics are obtained, the superconducting wire 51 and the first metal electrode 52 are connected by solder (for example, Patent Document 1). Specifically, the superconducting wire 51 is inserted into the recess 521 in a state where the melted solder is filled in the recess 521 of the metal electrode 52, and is vertically supported by a support member (not shown). When the solder is solidified by cooling, the superconducting wire 51 is fixed to the metal electrode 52. That is, the superconducting wire 51 and the metal electrode 52 are electrically connected via the solder 56. The connection between the superconducting wire 51 and the second metal electrode 53 is the same. Alternatively, the superconducting wire 51 and the metal electrode 52 may be connected by inserting the metal electrode 52 into the recess 521 and filling the recess 521 with solder.

Japanese Patent Laid-Open No. 10-275641

  However, in the connection portion of the superconducting wire described above, it is difficult to fill the concave portion 521 of the metal electrode 52 with molten solder and insert the superconducting wire 51 into the concave portion 521 so as to support it vertically. It becomes. As a result, there is a problem that the thickness of the solder layer interposed between the surface (first surface) of the superconducting wire on the superconducting layer side and the metal electrode cannot be set to a desired thickness, and the connection resistance increases. Further, when the thickness varies, the connection strength of the metal electrode 52 to the superconducting wire 51 may be reduced.

  That is, it is difficult to uniformly control the thickness of the solder layer, and it becomes difficult to stably obtain a desired connection resistance. In particular, when a plurality of superconducting wires are arranged and connected to one metal electrode, variation in connection resistance between the respective connecting portions increases, and there is a risk that drift that causes quenching may occur.

  An object of the present invention is to provide a highly reliable superconducting current lead and a method of manufacturing a superconducting wire that can be stably obtained by reducing connection resistance, have high connection strength, and have stable superconducting characteristics. is there.

One aspect of the superconducting current lead of the present invention is:
A tape-shaped superconducting wire in which an intermediate layer, a superconducting layer, and a stabilization layer are laminated in order on a metal substrate; and metal electrodes that are bonded to both ends of the superconducting wire;
A reinforcing member that accommodates a lead body including the superconducting wire and the metal electrode so as to have a predetermined inter-electrode distance;
With
The metal electrode is composed of a plurality of divided bodies, and is joined to the superconducting wire by sandwiching an end portion of the superconducting wire at a joining surface of the plurality of divided bodies.
Take the configuration.

One aspect of the method of manufacturing a superconducting current lead of the present invention is:
A tape-shaped superconducting wire in which an intermediate layer, a superconducting layer, and a stabilizing layer are sequentially laminated on a metal substrate, a metal electrode joined to both ends of the superconducting wire, and a lead including the superconducting wire and the metal electrode In the method of manufacturing a superconducting current lead, the main body is accommodated in the reinforcing member so as to have a predetermined inter-electrode distance, and the superconducting current lead is manufactured.
The metal electrode is composed of a plurality of divided bodies,
An arrangement step of arranging an end of the superconducting wire between the plurality of divided bodies;
In the state where the superconducting wire is pressed by the plurality of divided bodies, a connecting step of connecting the superconducting wires with solder at the joint surfaces of the plurality of divided bodies,
It was made to have.

  According to the present invention, it is possible to provide a highly reliable superconducting current lead that can be stably obtained by reducing connection resistance, has high connection strength, and has stable superconducting characteristics.

The figure which shows the connection structure of the superconducting wire and the electrode in the conventional superconducting current lead The figure which shows the superconducting magnet apparatus using the superconducting electric current lead which concerns on one embodiment of this invention The figure which shows typically the structure of the superconducting wire in the superconducting current | flow lead which concerns on one embodiment of this invention. 1 is a perspective view of a superconducting current lead according to an embodiment of the present invention. FIG. 5A is a plan view of the superconducting current lead, and FIG. 5B is a side view of the superconducting current lead according to the embodiment of the present invention. Sectional view taken along line II-II in FIG. Sectional drawing of the part shown by the III-III line of FIG. IV-IV arrow directional cross-sectional view in FIG. Exploded perspective view showing electrode configuration The figure which shows the manufacturing method of the superconducting current lead schematically The perspective view which shows the principal part structure of the modification 1 of the superconducting electric current lead of one embodiment of this invention Sectional drawing which shows the principal part structure of the modification 1 of the superconducting electric current lead of one embodiment of this invention

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing a superconducting magnet device 1 using a superconducting current lead 10 according to an embodiment of the present invention. FIG. 3 is a diagram schematically showing the configuration of the superconducting wire 11 in the superconducting current lead 10 according to the embodiment of the present invention. FIG. 4 is a perspective view of the superconducting current lead 10 according to the embodiment of the present invention.

  A superconducting magnet apparatus 1 shown in FIG. 2 includes a superconducting current lead 10, a normal conducting current lead 35, a superconducting coil 20, a power source 30, a low-temperature container 40, and the like.

  The cryogenic container 40 has a double structure composed of an inner container 41 and an outer vacuum chamber 42. The container 41 is connected to a refrigerator (not shown). The vacuum chamber 42 is connected to a vacuum pump (not shown), and the inside is kept in a vacuum state.

  The superconducting coil 20 is a coil wound with a superconducting wire. The superconducting coil 20 is disposed in a container 41 serving as a low temperature part. The superconducting coil 20 has a coil electrode 21 for connecting to the superconducting current lead 10.

  The power supply 30 is disposed in a normal temperature part that is outside the cryogenic container 40. The power supply 30 supplies current to the superconducting coil 20 via the normal conducting current lead 35 and the superconducting current lead 10. The normal conductive current lead 35 is, for example, a copper wire.

  As shown in FIG. 2, the superconducting current lead 10 includes a plurality of tape-shaped superconducting wires 11, a first electrode 12-1, a second electrode 12-2, and a reinforcing member (here, as a cylindrical reinforcing member). 14) (referred to as a cylindrical reinforcing member). The superconducting current lead 10 is disposed in the container 41. In the superconducting current lead 10, one end of the superconducting wire 11 on the high temperature side is connected to the first electrode 12-1, and the other end on the low temperature side is connected to the second electrode 12-2. The superconducting current lead 10 is formed so that the first electrode 12-1, the superconducting wire 11 and the second electrode 12-2 are arranged in a straight line in a normal state. The superconducting current lead 10 is connected to a conductor lead-out portion (not shown) connected to the normal conducting current lead 35 disposed at a predetermined position by the first electrode 12-1, and the second electrode 12-2. It is connected to the coil electrode 21 of the superconducting coil 20 arranged at a predetermined position.

  The superconducting current lead 10 has a configuration in which a plurality of superconducting wires 11 (here, two) are provided. However, the configuration is not limited to this, and a configuration in which one superconducting wire 11 is used, or a configuration in which three or more superconducting wires 11 are provided. It may be.

  The superconducting wire 11 is a tape-like wire having a superconducting layer 113 as shown in FIG. The superconducting wire 11 has a laminated structure in which an intermediate layer 112, a superconducting layer 113, and a stabilizing layer 114 are formed in this order on a tape-shaped metal substrate 111, for example, and has flexibility.

  The metal substrate 111 may be, for example, a Ni—Cr system (specifically, a Ni—Cr—Fe—Mo system Hastelloy (registered trademark) B, C, X, etc.), a W—Mo system, a Fe—Cr system (for example, , Austenitic stainless steel) or Fe—Ni (for example, non-magnetic composition type) and other low magnetic crystal grain non-oriented heat resistant high strength metal substrates.

The intermediate layer 112 has, for example, a first intermediate layer (diffusion prevention layer) for preventing the diffusion of elements from the metal substrate 111 to reach the superconducting layer 113, and orients crystals of the superconducting layer 113 in a certain direction. A plurality of intermediate layers, such as a second intermediate layer (alignment layer). The first intermediate layer is composed of, for example, a gallium-doped zinc oxide layer (GZO) or an yttrium-stabilized zirconia layer (YSZ). For example, an ion beam assisted deposition (IBAD) can be applied to form the first intermediate layer. The second intermediate layer is composed of, for example, a cerium oxide layer (CeO ₂ ). For example, an RF sputtering method can be applied to form the second intermediate layer. Further, as an intermediate layer 112 having a structure of two or more layers, an MgO layer formed by an IBAD method and an LaMnO ₃ layer formed by a sputtering method are sequentially stacked between a GZO layer as a first intermediate layer and a CeO ₂ layer. It is good also as what you did.

Superconducting layer 113, for example REBa _y Cu ₃ O _z based superconductor (RE is, Y, Nd, Sm, Eu , Gd, Tb, Dy, Ho, Er, 1 or 2 or more selected from Tm and Yb It is a rare earth element and is composed of an oxide superconductor such as y ≦ 2 and z = 6.2 to 7). A typical example of the RE-based superconductor is an yttrium-based superconductor represented by YBa ₂ Cu ₃ O ₇ . The superconducting layer 113 is formed by metal-organic deposition (MOD), pulsed laser deposition (PLD), sputtering, or metal organic chemical vapor deposition (MOCVD). Vapor Deposition) can be applied.

In the superconducting layer 113, it is preferable that 50 [nm] or less oxide particles containing at least one of Zr, Sn, Ce, Ti, Hf, and Nb are dispersed as magnetic flux pinning points. In this case, as a method for forming the superconducting layer 113, a TFA-MOD method using trifluoroacetate (TFA) is suitable. For example, Zr-containing oxide particles (BaZrO ₃ ) are added to the superconducting layer 113 made of a RE-based superconductor by mixing a Zr-containing naphthenate having a high affinity with Ba into a Ba solution containing TFA. It can be distributed as flux pinning points. A known technique can be applied to the method of dispersing the magnetic flux pinning points in the superconducting layer 113 (for example, JP 2012-059468 A).

  By dispersing the magnetic flux pinning points in the superconducting layer 113, even if the superconducting wire 11 is used in a curved state, it is hardly affected by the magnetic field and exhibits stable superconducting characteristics.

  The stabilization layer 114 is a layer for protecting the superconducting layer 113 mainly from moisture and the like, and for diverting the current when the superconducting state is partially broken and resistance is generated (normal conducting transition). The stabilization layer 114 is preferably made of a material having a low electrical resistivity and a high thermal conductivity, for example, Ag or Cu. For example, a sputtering method can be applied to form the stabilization layer 114.

  In the superconducting wire 11, the surface on the superconducting layer 113 side (stabilizing layer 114 side) is referred to as a first surface 11a, and the surface on the metal substrate 111 side is referred to as a second surface 11b.

  The 1st electrode 12-1 (high temperature side electrode) and the 2nd electrode 12-2 (low temperature side electrode) are comprised with metal materials, such as copper or a copper alloy. The first electrode 12-1 is disposed in the vicinity of the bottom surface of the container 41 and is connected to the normal conductive current lead 35 via a conductor lead-out portion (not shown). The temperature in the vicinity of the first electrode 12-1 is, for example, 77K. The second electrode 12-2 is disposed in the vicinity of the superconducting coil 20 and is connected to the coil electrode 21 of the superconducting coil 20. The temperature in the vicinity of the second electrode 12-2 is, for example, 4.2K.

  FIG. 5 is a diagram showing a superconducting current lead 10 according to an embodiment of the present invention, FIG. 5A is a plan view of the superconducting current lead 10, and FIG. 5B is a side view of the superconducting current lead 10. 6 is a cross-sectional view taken along the line II-II in FIG. 5, and FIG. 7 is a cross-sectional view taken along the line III-III in FIG. 8 is a cross-sectional view taken along the line IV-IV in FIG. 5, and FIG. 9 is an exploded perspective view showing the configuration of the electrodes. In FIG. 9, the solder 13 between the joint surfaces 122a and 124a is omitted.

  As shown in FIGS. 6 and 8, the first electrode 12-1 and the second electrode 12-2 are each in the extending direction of the superconducting wire 11 to be connected (also the longitudinal direction of the superconducting current lead). Superconducting wire 11 is attached to end faces (end faces of the electrodes facing each other).

  In addition, the 1st electrode 12-1 and the 2nd electrode 12-2 are comprised in the same shape in this Embodiment, and are joined to each of the both ends of the superconducting wire 11 in the same state. Thereby, the structure of the 1st electrode 12-1 and the 2nd electrode 12-2 is also called the electrode 12, and it demonstrates with the connection structure with the superconducting wire 11. FIG.

  The electrode 12 (12-1, 12-2) has a divided body (first and second divided bodies 122, 124) divided into a plurality of parts, and sandwiches the end of the superconducting wire 11 with the divided body. To the superconducting wire 11. The electrodes 12 constitute a lead body by being joined to both ends of the superconducting wire 11.

  Here, as shown in FIGS. 6 and 8, the electrode 12 includes a first divided body 122 having a joining surface 122a (see FIGS. 8 and 9) to which the end of the superconducting wire 11 is joined, and a first divided body. And a second divided body 124 that sandwiches the superconducting wire 11 together with the joint surface 122a.

  The first divided body 122 includes a joining portion 1221 having a joining surface 122a sandwiching the superconducting wire 11 together with the joining surface 124a of the second divided body 124, a fixing portion 1222 fixed to the tubular reinforcing member 14, and a terminal connection portion 1223. And having.

  As shown in FIGS. 8 and 9, in the present embodiment, the electrode 12 has a cylindrical shape, and the joint portion 1221 is formed in a half-circular column shape with a semicircular cross section together with the second divided body 124. . The joint portion 1221 is formed so as to protrude from one end surface of the columnar fixing portion 1222, and the terminal connection portion 1223 is exposed to the other end surface of the fixing portion 1222 outside the cylindrical reinforcing member 14. Protrusively formed. Note that the electrode 12 may be formed in a prismatic shape. In that case, the joint portion 1221 and the second divided body 124 are formed in a rectangular parallelepiped shape having a rectangular cross section.

  In the present embodiment, the first electrode 12-1 and the second electrode 12-2 are formed in a columnar shape by the joint portion 1221 and the second divided body 124, and have a predetermined distance (distance between electrodes). Are arranged opposite to each other.

  The superconducting wire 11 is disposed between the bonding surface 122a of the bonding portion 1221 of the first divided body 122 and the bonding surface 124a of the second divided body 124. Superconducting wire 11 is joined to each of joining surfaces 122a and 124a via solder 13.

  The superconducting wire 11 is arranged between the electrodes 12 so as to extend in the longitudinal direction, and is constructed between the electrodes 12. In the present embodiment, when the lead main body is accommodated in the cylindrical reinforcing member 14, the superconducting wire 11 bends between the first electrode 12-1 and the second electrode 12-2. (See FIG. 8).

  Specifically, the superconducting wire 11 opposes the first surface 11a, which is a surface on the superconducting layer 113 side (stabilizing layer 114 side), to the bonding surface 122a.

  Here, the end portions of the plurality of superconducting wires 11 are arranged in parallel between the joining surfaces 122a and 124a, and the first surface 11a of each superconducting wire 11 is opposed to the joining surface 122a. And these 1st surfaces 11a are joined to the joint surface 122a via the solder 13, and the superconducting wire 11 and the electrode 12 are electrically connected. With this joining structure, the current from the superconducting wire 11 does not pass through the joining surface perpendicular to the longitudinal direction of the first divided body 122 and the second divided body 124, and the joined portion 1221 and the fixed portion of the first divided body 122. Conduction is performed in the order of 1222 and the terminal connection portion 1223.

  Further, the first divided body 122 and the second divided body 124 together with the solder 13 in a state in which the end surfaces of the superconducting wire 11 between the bonding surfaces 122a and 124a are pressed against each other over the entire bonding surfaces 122a and 124a. It is fixed in a clamped state. Thereby, the improvement of the connection intensity | strength of the electrode 12 provided with the 1st division body 122 and the 2nd division body 124 and the superconducting wire 11 is achieved.

  The fixing part 1222 is interposed between the joint part 1221 and the terminal connection part 1223. Here, the fixing portion 1222 is formed in a columnar shape having an outer diameter substantially the same as or the same as the outer diameter of the joining portion 1221 and the second divided body 124 in a state where the oxide superconducting wire 11 is sandwiched. The fixing portion 1222 is fixed to the cylindrical reinforcing member 14 via the fixing pin 15 with the terminal connection portion 1223 exposed to the outside of the cylindrical reinforcing member 14.

  The terminal connection portion 1223 constitutes the end portion of the superconducting current lead 10. That is, the terminal connection portion 1223 in the first electrode 12-1 is connected to the conductor lead portion (not shown) connected to the normal conductive current lead 35 (see FIG. 2) so as to be conductive, and the second electrode 12- 2 is connected to the coil electrode 21 (see FIG. 1) of the superconducting coil 20 so as to be conductive.

  The cylindrical reinforcing member 14 is a cylindrical body that covers the superconducting wire 11, and accommodates and supports the lead body in which the electrodes 12 are joined to both ends of the superconducting wire 11 with a predetermined distance between the electrodes 12. To do. The cylindrical reinforcing member 14 is installed between the electrodes 12 (12-1, 12-2) so as to cover the superconducting wire 11.

  The cylindrical reinforcing member 14 is made of a low heat conductive material (for example, fiber reinforced plastics (GFRP), stainless alloy, nickel base alloy, titanium alloy, etc.).

  The tubular reinforcing member 14 preferably has a lower thermal conductivity than the superconducting wire 11. Thereby, the amount of heat penetration from the outside can be reduced. From the viewpoint of reducing the amount of heat penetration, GFRP is preferred. The thermal conductivity of GFRP at 77 K is 0.39 W / (m · K), which is significantly smaller than the thermal conductivity of the superconducting wire 11. Moreover, the thermal contraction rate of GFRP at 77 K is 0.213%, which is larger than the thermal contraction rate of the superconducting wire 11.

  On the other hand, from the viewpoint of protecting the superconducting magnet device 1 when the superconducting wire 11 is damaged, a stainless alloy, nickel-base alloy, titanium alloy, or the like that functions as a bypass is preferable. The thermal conductivity of the stainless alloy (SUS304, SUS316) at 77K is 7.9 W / (m · K), which is smaller than the thermal conductivity of the superconducting wire 11. Further, the heat shrinkage rate of the stainless alloy (SUS304) at 77K is 0.281, which is larger than the heat shrinkage rate of the superconducting wire 11.

  According to the superconducting current lead 10 configured as described above, the electrode 12 joined at both ends of the superconducting wire 11 has a first divided body 122 and a second divided body 124 which are divided into a plurality of parts. The electrode 12 is joined to the superconducting wire 11 with the end portion of the superconducting wire 11 sandwiched between the divided body 122 and the second divided body 124. As a result, the end portion of the superconducting wire 11 between the first divided body 122 and the second divided body 124 is uniformly bonded to the first divided body 122 and the second divided body 124 in a stable state. Thereby, the solder 13 between the electrodes 12 is also extremely thin and uniform, and is joined to the first divided body 122 and the second divided body 124 together with the solder 13. Therefore, a desired connection resistance can be stably obtained, and the connection resistance can be reduced.

  Next, a method for manufacturing the superconducting current lead 10 will be described with reference to FIG. FIG. 10 is a diagram schematically showing a method of manufacturing a superconducting current lead.

  First, as illustrated in FIG. 10A, in the electrode 12, the superconducting wire 11 is disposed between the bonding surface 122 a of the bonding portion 1221 of the first divided body 122 and the bonding surface 124 a of the second divided body 124. In FIG. 10, solder plating 131 is applied to each of the superconducting wire 11 and the joining surfaces 122a and 124a. However, the present invention is not limited to this, and the joining surfaces 122a and 124a may be filled during joining.

  Then, as illustrated in FIG. 10B, the superconducting wire 11 is disposed between the joint portion 1221 of the first divided body 122 and the second divided body 124. At this time, the superconducting wire 11 is arranged with the first surface 11a on the stabilization layer 114 (see FIG. 3) side facing the joining surface 122a and facing the joining surface 122a.

  Then, as shown in FIG. 10C, the bonding surfaces 122a and 124a are heated using a heating device (not shown) or the like, specifically, the bonding surfaces 122a and 124a are heated to slightly melt the solder plating 131. Here, heating is performed at 195 [° C.] to 197 [° C.]. At this time, the first divided body 122 and the second divided body 124 are temporarily fixed in a state where the superconducting wire 11 is disposed between the joint surfaces 122a and 124a. Therefore, the space between the joint surfaces 122a and 124a becomes narrow due to the weight of the second divided body 124 and the like.

  Next, the bonding surface 122a of the first divided body 122 and the bonding surface 124a of the second divided body 124 are pressed against each other with a predetermined pressure using a pressing jig. The pressing jig includes a pair of metal plates arranged so as to sandwich the first divided body 122 and the second divided body 124 in the same direction as the sandwiching direction of the superconducting wire 11, the first divided body 122, and the second divided body. A plurality of (for example, four) bolts are provided between the metal plates so as to surround the body 124. That is, the direction which pinches | interposes the 1st division body 122 and the 2nd division body 124 by tightening a volt | bolt (for example, diameter 4 [mm]) managed by predetermined torque (for example, 0.1 [N * m]). Pressure. Thereby, the joint surface 122a of the 1st division body 122 and the joint surface 124a of the 2nd division body 124 mutually press uniformly on the whole surface. Then, excess solder flows between the joint surfaces 122a and 124a, and the joint surfaces 122a and 124a are heated while being uniformly pressed through the superconducting wire 11 (that is, the solder 13 is removed). Via). As a result, the connection strength is increased, the superconducting wire 11 is hardly detached, and the contact resistance can be reduced.

  Thus, in joining the electrodes 12-1, 12-2 and the superconducting wire 11, the end of the superconducting wire 11 is disposed between the first divided body 122 and the second divided body 124 (arranging step), and then In a state where the superconducting wire is pressed by the first divided body 122 and the second divided body 124, the joining surfaces 122a and 124a of the first divided body 122 and the second divided body 124 and the superconducting wire 11 are connected by the solder 13 ( Connection process). Next, the electrode 12 joined to the superconducting wire 11 is accommodated in the cylindrical reinforcing member 14 at a predetermined interval, and is fixed via a fixing pin 15 to produce a superconducting current lead.

  In the superconducting current lead 10, the electrode 12 is composed of a plurality of divided bodies (here, the first divided body 122 and the second divided body 124). You may comprise by the division body of. That is, in the superconducting current lead, the electrode 12 may be configured in any way as long as the ends of the superconducting wire 11 are sandwiched between the joint surfaces of the plurality of divided bodies.

  A modification of such an electrode will be described with reference to FIGS. FIG. 11 is a perspective view showing a configuration of a main part of Modification 1 of the superconducting current lead according to the embodiment of the present invention, and FIG. 12 shows Modification 1 of the superconducting current lead according to the embodiment of the present invention. It is sectional drawing which shows the principal part structure.

  The electrodes 12A shown in FIGS. 11 and 12 are connected to the ends of a pair of wires 110 in which two superconducting wires 11 are bonded to each other on the substrate side surface, that is, the second surface 11b.

  The electrode 12A includes a first divided body 122A and a second divided body 124A that sandwich the end portions of the wire pair 110 between the bonding surfaces 1221a and 1241a.

  The first divided body 122A and the second divided body 124A are formed symmetrically with respect to the center line of the superconducting current lead extending in the longitudinal direction. Specifically, the first divided body 122A and the second divided body 124A are formed in the same shape, and the joining surfaces 1221a and 1241a each constitute a part of the bottom surface. It is formed so as to be symmetrical in the vertical direction around the bottom surface.

  The joining surfaces 1221a and 1241a of the first divided body 122A and the second divided body 124A are disposed to face each other. The joining surfaces 1221a and 1241a sandwich each of the superconducting wires 11 in the wire pair 110. When the first divided body 122A and the second divided body 124A are bonded to each other, the first divided body 122A and the second divided body 124A are portions extending in the longitudinal direction including the bonding surfaces 1221a and 1241a, and constitute a bonding portion 1221A that sandwiches the wire pair 1120 (superconducting wire 11). To do. Further, a fixing portion 1222A fixed to a reinforcing member (not shown) and a terminal connection portion 1223A are formed continuously with the joining portion 1221A. In addition, although the external shape of the junction part 1221A and the fixing | fixed part 1222A is illustrated here as prismatic shape (specifically rectangular parallelepiped shape), you may form not only in this but in a column shape. In this case, the portions of the first divided body 122A and the second divided body 124A that constitute the joining portion 1221A and the fixing portion 1222A are formed in a semicircular cross section.

  In the joining portion 1221A of the electrode 12A, the first surfaces 11a of the superconducting wires 11 and 11 disposed above and below the wire pair 110 are respectively connected to the joining surfaces 1221a and 1241a of the first divided body 122A and the second divided body 124A. Are joined using solder 13A.

  The pair of electrodes 12A to which the ends of the wire pair 110 are bonded in this way have an outer diameter corresponding to the electrode 12A with a predetermined interval, like the superconducting current lead 10 shown in FIG. It is accommodated in a supported state by a rectangular tube-shaped reinforcing member made of the same material as that of the reinforcing member 14. Thereby, a superconducting current lead using the electrode 12A is formed.

  Also, the first divided body 122A and the second divided body 124A of the electrode 12A are joined to the superconducting wires of the wire pair 110 at the joint surfaces 122a and 124a, similarly to the first divided body 122 and the second divided body 124 of the electrode 12. 11 are joined to the superconducting wire 11 while pressing each other. For example, the wire pair 110 is disposed between the joining surfaces 122a and 124a, and the above-described pressing jig is disposed in the same manner as in the manufacture of the electrode 12. In other words, a pair of metal plates are arranged above and below so as to sandwich the first divided body 122A and the second divided body 124A with the wire rod pair 110 interposed therebetween, and the bolt is set to a predetermined torque (0.1 [N · m ]) And tighten. Then, pressure is applied to the first divided body 122A and the second divided body 124A in the direction in which the superconducting wire 11 is sandwiched, and the joining surfaces 122a and 124a are pressed against the wire pair 110. As a result, the joining surfaces 122a and 124a are joined to the superconducting wire 11 in a state where the connection strength is high and the connection resistance value is lowered.

  Because of this configuration, the superconducting current lead using the electrode 12 </ b> A has the same effects as the superconducting current lead 10.

  According to the configuration of the electrode 12A, as shown in FIGS. 11 and 12, when the superconducting wire 11 is bonded to the second surface 11b side to form the wire pair 110, the first surface 11a is formed of the wire pair 110. Are exposed on the front and back sides, and are bonded to the bonding surfaces 122a and 124a arranged to face each other.

  Here, the divided body having the joint surfaces 122a and 124a is symmetrical in the vertical direction including the portion corresponding to the terminal connection portion, that is, is formed in the same shape. Thereby, even if it supplies with electricity to wire pair 110 and electrode 12A, a drift does not arise.

  As Example 1, a superconducting current lead 10 according to the embodiment shown in FIGS. 4 to 10 was produced. Specifically, two superconducting wires were arranged in parallel on the electrode 12, and the ends of these superconducting wires were joined. And about the some sample, the connection part of a superconducting wire and an electrode was evaluated. Specifically, the superconducting current lead was placed in liquid nitrogen (77 K), and the connection resistance of the connection part between the superconducting wire and the low temperature side electrode was measured, and the connection resistance value was 0.8 [μΩ]. .

  As Example 2, a superconducting current lead was manufactured using the superconducting wire used in Example 1, a reinforcing member made of the same material as in Example 1, and the electrodes shown in FIGS.

  In Example 2, in the configuration shown in FIGS. 11 and 12, two connection pairs 11 formed by pairing two superconducting wires 11 and 11 were joined in parallel to the electrode 12A. That is, in the superconducting current lead of Example 2, the ends of two wire pairs 110 arranged in parallel (a total of four superconducting wires 11) were joined to the electrode 12A shown in FIGS. And similarly to Example 1, the connection part of the superconducting wire 11 and an electrode was evaluated. The connection resistance value of the connection portion between the superconducting wire and the low temperature side electrode was 0.4 [μΩ].

  As Comparative Example 1, a conventional superconducting current lead shown in FIG. 1 was manufactured using two superconducting wires similar to those of Example 1. At this time, the outer diameter of the electrode was the same as the outer diameter of the electrode in Example 1. Furthermore, as Comparative Example 2, the conventional superconducting current lead shown in FIG. 1 was manufactured using four superconducting wires similar to those of Example 1. In Comparative Example 1 and Comparative Example 2, the same evaluation as in Example 1 and Example 2 was performed. The connection resistance value of the connection portion between the superconducting wire and the low temperature side electrode in Comparative Example 1 was 2.5 [μΩ]. Moreover, the connection resistance value of the connection part between the superconducting wire and the low temperature side electrode in Comparative Example 2 was 1.2 [μΩ].

  As a result, when Example 1 using two superconducting wires 11 was compared with Comparative Example 1, it was found that the connection resistance value of Example 1 was lower than the connection resistance value of Comparative Example 1. In addition, the connection strength of Example 1 in which the superconducting wire 11 was connected while being pressed with the divided bodies 122 and 124 that were divided electrodes was higher than that of Comparative Example 1 in which both were connected without being pressed. Moreover, when Example 2 using four superconducting wires was compared with Comparative Example 2, it was found that the connection resistance value of Example 2 was lower than the connection resistance value of Comparative Example 2. In addition, the connection strength of Example 2 in which the superconducting wire 11 was connected while being pressed by the divided bodies 122A, 124A, and 126 that were divided electrodes was higher than that of Comparative Example 2 in which both were connected without being pressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The embodiment of the present invention has been described above. The above description is an illustration of a preferred embodiment of the present invention, and the scope of the present invention is not limited to this. That is, the description of the configuration of the apparatus and the shape of each part is an example, and it is obvious that various modifications and additions to these examples are possible within the scope of the present invention.

  The superconducting current lead and the method for manufacturing a superconducting current lead according to the present invention provide a superconducting current lead having a high connection strength and stable superconducting characteristics, which can be stably obtained by reducing connection resistance. Useful.

DESCRIPTION OF SYMBOLS 1 Superconducting magnet apparatus 10 Superconducting current lead 11 Superconducting wire 11a First surface 11b Second surface 12, 12A Electrode 12-1 First electrode (room temperature side electrode)
12-2 Second electrode (low temperature side electrode)
13, 13A Solder 14 Cylindrical reinforcing member 15 Fixing pin 20 Superconducting coil 21 Coil electrode 30 Power supply 40 Low temperature container 110 Wire pair 111 Metal substrate 112 Intermediate layer 113 Superconducting layer 114 Stabilization layer 122, 122A First divided bodies 122a, 124a, 1221a, 1241a Joint surface 124, 124A Second divided body 131 Solder plating 1221, 1221A Joint portion 1222, 1222A Fixing portion 1223, 1223A Terminal connection portion

Claims (5)

A tape-shaped superconducting wire in which an intermediate layer, a superconducting layer, and a stabilization layer are laminated in order on a metal substrate; and metal electrodes that are bonded to both ends of the superconducting wire;
A reinforcing member that accommodates a lead body including the superconducting wire and the metal electrode so as to have a predetermined inter-electrode distance;
With
The metal electrode is composed of a plurality of divided bodies, and is joined to the superconducting wire by sandwiching an end portion of the superconducting wire at a joining surface of the plurality of divided bodies.
A superconducting current lead. A plurality of the superconducting wires;
The superconducting current lead according to claim 1, wherein the plurality of superconducting wires are connected to a joint surface of each of the divided bodies. The plurality of divided bodies include a first divided body and a second divided body that sandwich an end portion of the superconducting wire with each other's joint surface,
The first divided body and the second divided body are formed in the same shape,
The superconducting current lead according to claim 1 or 2. The superconducting layer is formed by a TFA-MOD method,
3. The oxide particle of 50 μm or less containing at least one of Y, Zr, Sn, Ti, and Ce is dispersed in the superconducting layer as a magnetic flux pinning point. The superconducting current lead according to one item. A tape-shaped superconducting wire in which an intermediate layer, a superconducting layer, and a stabilizing layer are sequentially laminated on a metal substrate, a metal electrode joined to both ends of the superconducting wire, and a lead including the superconducting wire and the metal electrode In the method of manufacturing a superconducting current lead, the main body is accommodated in the reinforcing member so as to have a predetermined inter-electrode distance, and the superconducting current lead is manufactured.
The metal electrode is composed of a plurality of divided bodies,
An arrangement step of arranging an end of the superconducting wire between the plurality of divided bodies;
In the state where the superconducting wire is pressed by the plurality of divided bodies, a connecting step of connecting the superconducting wires with solder at the joint surfaces of the plurality of divided bodies,
Having
A method of manufacturing a superconducting current lead.

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