JP3324288B2 - Method for producing Al-stabilized Nb-Ti superconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an Al-stabilized Nb-Ti superconducting conductor, and more particularly to a method for stabilizing a conductor by arranging an Al-stabilizing wire having a fan-shaped cross section on the outer periphery of the superconducting wire and closely adhering the solder. With improved properties and current density
The present invention relates to a method for manufacturing a stabilized Nb-Ti superconductor.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, an Al stabilizing wire 3 coated with aluminum 2 by a Cu--Ni alloy 1 is disposed at the center for storing superconducting power, and Cu--N
There is an Al-stabilized Nb-Ti superconductor having a structure in which twelve i / Cu / Nb-Ti superconductors 4 are arranged and twisted. The Al stabilizing wire 3 is formed by twisting seven strands, and the Al stabilizing wire 3 and the Cu-Ni
The / Cu / Nb-Ti superconducting wire 4 has a gap filled with solder after the stranded wire processing. The outer diameter of the conductor is 20 mm.

[0003]

However, according to the conventional Al-stabilized Nb-Ti superconducting conductor, since the superconducting wire is arranged on the outer periphery of the stabilizing wire, the cross-sectional area of the conductor is reduced by a gap or a solder portion. This disadvantageously increases the current density of the conductor.

[0004] In the structure in which the outer periphery of the stabilizing wire is surrounded by the superconducting wire, there is a risk that the stabilizing wire will not function if the superconductivity is broken when the temperature of Al rises due to lack of cooling of the stabilizing wire.

In addition, it is difficult for solder to enter the gap between the stabilizing wire and the superconducting wire, and voids (voids) are generated between the wires, resulting in a decrease in electrical joining properties and a decrease in the stability of the superconducting conductor. is there. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an Al-stabilized Nb-Ti superconducting conductor which improves current density and stability of a stabilizing wire and a superconducting wire and has a small AC loss, and a method for manufacturing the same.

[0006]

SUMMARY OF THE INVENTION The present invention improves the current density and stability of a stabilizing wire and a superconducting wire and reduces the AC loss by using Cu-Ni / Cu / Nb coated on the surface by solder plating. A plurality of fan-shaped cross sections which are constituted by covering a Cu-Ni alloy with a Ti superconducting core wire and a stabilizing wire made of Al, and which are annularly arranged on the outer periphery of the Cu-Ni / Cu / Nb-Ti superconducting core wire; A Cu-Ni / Cu / Nb-
Provided is an Al-stabilized Nb-Ti superconducting conductor in which a gap between a Ti superconducting core and a plurality of fan-shaped Cu-Ni alloy-coated Al-stabilized cores is tightly joined by solder plating.

Further, the present invention relates to the above Al-stabilized Nb-
Cu-Ni / Cu / N for manufacturing Ti superconducting conductor
The surface of the b-Ti superconducting core wire is subjected to solder plating, and a plurality of Cu-N coated with a Cu-Ni alloy is coated on the outer periphery of the solder-plated Cu-Ni / Cu / Nb-Ti superconducting core wire.
i-alloy-coated Al-stabilized core wire is arranged and twisted, Cu
-Ni alloy coated Al stabilized core wire and Cu-Ni / Cu /
The Nb-Ti superconducting core wire is drawn to plastically deform the Cu-Ni alloy-coated Al stabilized core wire into a fan-shaped section, and the adjacent stabilized core wire and Cu-Ni / Cu / Nb-T
i The superconducting core wire is adhered, and after the wire drawing process, the adhered Cu
-Ni alloy coated Al stabilized core wire and Cu-Ni / Cu /
Provided is a method for manufacturing an Al-stabilized Nb-Ti superconducting conductor in which an Nb-Ti superconducting core wire is immersed in a solder bath to melt solder plating to thereby integrally solder-join the stabilized core wire and the superconducting core wire.

[0008]

According to the Al-stabilized Nb-Ti superconductor of the present invention and the method for producing the same, the stabilizing wire is arranged on the outer periphery of the superconducting wire and subjected to wire drawing, whereby the surface of both wires is formed. Since the solder plating fills the gap between the wires, the electrical connection is improved. The solder plating is melted by being immersed in a solder bath after wire drawing, and integrated without increasing the cross-sectional area of the stabilizing wire and the superconducting wire.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The Al-stabilized Nb-Ti superconductor of the present invention and a method of manufacturing the same will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of an Al-stabilized Nb-Ti superconducting conductor according to an embodiment of the present invention, in which a Cu-Ni / Cu / Nb-Ti extra-fine multi-core superconducting core wire 5 is disposed at the center. , Arranged annularly on the outer periphery of the superconducting core wire 5,
An Al stabilizing wire 6 coated with aluminum 2 by an i-alloy 1 is integrated by wire drawing, and the stabilizing wire 6 is formed in a fan-shaped cross section by wire drawing. The diameter of the conductor is 1.85 mm.

The surfaces of the superconducting core wire 5 and the stabilizing wire 6 are plated with solder, and the plating adheres to the surface by wire drawing.
In the solder plating, the superconducting wires 5 and 6 are melted by being immersed in a solder bath after wire drawing to fill gaps between the wires.

Hereinafter, a method for manufacturing an Al-stabilized Nb-Ti superconductor according to the present invention will be described with reference to FIG. First,
Cu-Ni / Cu / Nb-Ti extra-fine multi-core superconducting core wire and C
An Al-stabilized wire coated with aluminum by a u-Ni alloy is prepared, and after solder plating is performed on the surfaces of both wires, 12 stabilizing wires are arranged around the superconducting core wire and twisted ((a ) Stages).

Next, the twisted superconducting core wire and the stabilized wire are subjected to wire drawing. By this wire drawing process, the stabilizing wire arranged on the outer periphery of the superconducting core wire is in close contact with the surface of the superconducting wire and is integrated with the adjacent stabilizing wire,
At that time, it is plastically deformed into a sectoral cross section (stage (b)).

Here, assuming that the sum of the cross-sectional areas of the Cu—Ni / Al stabilizing wire is A ₁ and the cross-sectional area of the Cu—Ni / Cu / Nb—Ti superconducting core wire is A ₀ , the cross-sectional area ratio (A ₁ / A
₀ ) is set in the range of 0.4 to 1.2.

The reason for this setting is that when the sectional area ratio A ₁ / A ₀ ≧ 1.2, the sectional area of the Cu—Ni / Cu / Nb—Ti superconducting core wire with respect to the entire section of the superconducting conductor is And the current density of the conductor decreases. Also, when the cross-sectional area ratio is A ₁ / A ₀ ≦ 0.4, the ratio of Al to the entire cross section of the superconducting conductor is significantly reduced, and the stability is lowered.

Next, the integrated superconducting core wire and stabilizing wire are immersed in a solder bath. By passing the solder bath, the solder plating applied to the surfaces of the superconducting core wire and the stabilizing wire is melted to prevent voids between the wires, and the stabilizing wire is adhered by core wire processing. Then, the stabilizing wire and the superconducting wire are soldered together (step (c)).

Table 1 shows the specifications of the Al-stabilized Nb-Ti superconducting conductor manufactured through the above manufacturing steps together with the specifications of the conventional Al-stabilized Nb-Ti superconducting conductor shown in FIG.
Shown in In this embodiment, the Nb-Ti filament diameter, the total cross-sectional area of the Nb-Ti filament, and the total cross-sectional area of the Al-stabilized portion are set to substantially the same value in order to eliminate a difference in current density and stability comparison described later. are doing.

[Table 1]

FIG. 3 shows the voltage-current characteristics of the Al-stabilized Nb-Ti superconductor of the present invention (upper part) and the magnetic field of the conventional Al-stabilized Nb-Ti superconductor shown in FIG. 4 (lower part) of 4 Tesla. FIG. The voltage-current characteristics were measured by a four-terminal method with a superconducting conductor wound three turns around a cylindrical holder made of FRP. The measurement results were obtained by using an XY recorder and recording the current signal on the X axis and the output voltage signal on the Y axis.

According to FIG. 3, the Al of the present invention shown in the upper part
The voltage-current characteristics of the stabilized Nb-Ti superconductor have not been quenched, and an output voltage V of 20 μV or more has been obtained. On the other hand, in the conventional Al-stabilized Nb-Ti superconductor shown in the lower part, the current is about The conductor quenched at 1800 A, indicating low stability.

Regarding the current value, the critical current Ic of the Al-stabilized Nb--Ti superconductor of the present invention is 1950 A
On the other hand, it has been confirmed that the quench current Iq of the conventional Al-stabilized Nb-Ti superconducting conductor remains at 1810A.

Further, when the current density is calculated from the above results, the result obtained by dividing Ic or Iq of the superconducting conductor by the total cross-sectional area is 725 A / mm ² for the superconducting conductor of the present invention. Was 575 A / mm ² .

As described above, the stabilizing wire similarly plated with solder is arranged around the outer periphery of the superconducting wire coated with solder plating, wire-drawing is performed, and further immersed in a solder bath. It was confirmed that the electrical connection between the superconducting wire and the stabilizing wire was thereby improved. Wire drawing improves the adhesion of solder plating without increasing the cross-sectional area, and also contributes to the improvement in the mechanical strength of the integrated superconducting conductor,
As a result, the current density is improved.

[0023]

As described above, according to the Al-stabilized Nb-Ti superconducting conductor of the present invention, it is composed of a Cu-Ni / Cu / Nb-Ti superconducting core wire whose surface is coated by solder plating, and Al. Cu-Ni / Cu / Nb-Ti superconducting core wire is formed by covering a stabilizing wire with a Cu-Ni alloy.
-Ni alloy coated Al stabilized core wire, and Cu-Ni /
Cu / Nb-Ti superconducting core wire and a plurality of fan-shaped cross sections of Cu
Since the gap between the Ni-alloy-coated Al-stabilized core wires is tightly joined by solder plating, the current density and the stability of the stabilizing wire and the superconducting wire can be improved, and the AC loss can be reduced.

Further, according to the method for producing an Al-stabilized Nb-Ti superconductor of the present invention, the Cu-Ni / Cu / Nb-
A plurality of Cu-Ni alloy-coated Al-stabilized core wires in which the surface of a Ti superconducting core wire is subjected to solder plating, and the outer periphery of the Cu-Ni / Cu / Nb-Ti superconducting core wire subjected to the solder plating is coated with a Cu-Ni alloy. Are arranged and twisted, and Cu-N
i-alloy coated Al stabilized core wire and Cu-Ni / Cu / Nb
-Cu-Ni alloy coating A by drawing a Ti superconducting core wire
(1) The stabilized core wire is plastically deformed into a fan shape in cross section, and the adjacent stabilized core wire and the Cu—Ni / Cu / Nb—Ti superconducting core wire are adhered to each other.
i-alloy coated Al stabilized core wire and Cu-Ni / Cu / Nb
-Improve the current density and stability of the stabilizing wire and the superconducting wire by immersing the Ti superconducting core wire in a solder bath and melting the solder plating to integrally solder the stabilized core wire and the superconducting core wire. In addition, the AC loss can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an Al-stabilized Nb—Ti superconductor according to the present invention.

FIG. 2 is an explanatory view showing a manufacturing process of the Al-stabilized Nb—Ti superconductor of the present invention.

FIG. 3 is a sectional view showing a conventional Al-stabilized Nb—Ti superconductor.

FIG. 4 is an explanatory diagram showing voltage-current characteristics of an Al-stabilized Nb—Ti superconducting conductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cu-Ni alloy 2 Aluminum 3,6 Al stabilization wire 4 Cu-Ni / Cu / Nb-Ti superconducting wire 5 Cu-Ni / Cu / Nb-Ti extra-fine multi-core superconducting core wire

Continuation of front page (56) References JP-A-2-103812 (JP, A) JP-A-5-74234 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 12 / 00-13/00

Claims (1)

(57) [Claims] 1. An Al structure in which a stabilizing material wire is arranged on the outer periphery of a core wire made of an Nb—Ti alloy-based superconducting material.
A method for producing a stabilized Nb-Ti superconducting conductor , comprising: soldering a surface of a Cu-Ni / Cu / Nb-Ti superconducting core wire;
Plating applied, has been subjected to the solder plating Cu-Ni / Cu / Nb- T
a plurality of i superconducting core wires whose outer periphery is covered with a Cu-Ni alloy
Cu-Ni alloy coating Al twisted by arranging the stabilizing core case of
The Cu-Ni alloy-coated Al stabilized core wire and the Cu-
Ni / Cu / Nb-Ti superconducting core wire is drawn and
The plastic deformation of the Cu-Ni alloy coated Al stabilized core wire into a fan-shaped cross section
Shaped and adjacent stabilizing core wire, and said Cu-
NI / Cu / Nb-Ti superconducting core wire is adhered, and after the wire drawing process, the adhered Cu-Ni alloy coating A
1 stabilizing core wire and said Cu-Ni / Cu / Nb-Ti super
The conductive core is immersed in a solder bath to melt the solder plating.
The stabilizing core wire and superconducting core wire are
A method for producing an Al-stabilized Nb-Ti superconducting conductor , characterized by performing field bonding .