JP2000057865A - Manufacture of compound superconductive wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict decrease of Jc to the minimum and increase an N value, by rolling, thinning, and thus unifying layered sheets of a Cu-based metallic material and of a first base metal material forming an alloy layer therewith, packing a plurality of composite single-core wires obtained by winding it around a second base metal material into a cylindrical container made of Cu to form a composite rod, and drawing and further heat treating it. SOLUTION: An Nb-Sn compound superconductive wire has Nb3 Sn filaments embedded in a bronze layer at intervals so as not to contact each other. In order to embed therein as many Nb3 Sn filaments as possible, the intervals of the filaments in a boundary area of an ε-phase bronze layer produced by preliminary heat treatment at 300 to 600 deg.C are made greater than in the other areas and a precursor of the superconducting wire is heat treated. In the preliminary heat treatment, prior to the heat treatment of the precursor of the superconductive wire, it is previously heated to 300 to 600 deg.C to diffuse an Sn- based metallic material in a center into a surrounding Cu-based metallic material, and thus the bronze layer of a Cu-Sn alloy is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compound superconducting wire for a high magnetic field superconducting magnet and a method for producing the same.
In particular, the present invention can be suitably applied to an Nb-Sn compound-based superconducting wire and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, superconducting wires have been manufactured by a method called bronze method or internal diffusion method.

FIG. 23 and FIG.
Described 1-16141 discloses an explanatory view showing a cross section of a conventional precursor and Nb ₃ Sn based superconducting wire after the heat treatment of the Nb ₃ Sn based superconducting wire before the heat treatment by an internal diffusion method. In this specification, a wire before heat treatment, that is, a wire before superconductivity is called a precursor of a superconducting wire, and a superconducting wire after heat treatment is called a superconducting wire. In FIG.
41 is a precursor of the superconducting wire before heat treatment, 43 is an Nb-based metal filament which becomes superconducting by heat treatment, 44 is a barrier layer such as Ta, 45 is a stabilizing layer such as oxygen-free copper,
46 is a Cu-based metal material and 47 is a Sn-based metal material.
In 4, 48 is a superconducting wire after heat treatment, 49 is a superconducting Nb ₃ Sn filament, and 50 is a bronze with a low Sn concentration.

The superconducting wire is obtained by subjecting a precursor of the superconducting wire to a heat treatment at a high temperature (generally 600 to 800 ° C.) to generate an Nb ₃ Sn compound on the Nb-based metal filament. .

A method for manufacturing an Nb ₃ Sn-based superconducting wire using the internal diffusion method is as follows. First, an Nb-based metal material is inserted into a Cu tube, and the cross section is reduced to a certain diameter to obtain a single core wire. Cut this single core wire to an appropriate length,
Into multiple containers. However, a Cu-based metal material such as a Cu rod or a plurality of Cu wires is disposed at the center. After the air in the container is eliminated, the lid is welded and sealed, and after extruding, the central Cu-based metal material is mechanically perforated. A Sn-based metal material is inserted into this hole, and T
A tube of a or Nb, and further, a tube of Cu is coated around the tube, and the cross section is reduced. In order to increase the current capacity, the obtained composite wire is filled in a plurality of Cu tubes to reduce the cross section. After the cross section is reduced to the final diameter, twist processing and heat treatment are performed. By this heat treatment, Sn
Diffuses into the surrounding Cu to form a Cu—Sn alloy, and further reacts with the Nb-based metal filament to generate Nb ₃ Sn in part or all of the filament.

The precursor of the superconducting wire in the internal diffusion method has a structure in which an Nb-based metal filament and a Sn-based metal core are buried in a Cu-based metal material. In particular, in order to increase the critical current density (Jc), which is one of the superconducting characteristics, as much as possible, the Nb-based metal filament is embedded as densely as possible in the Cu-based metal material. When the superconducting wire is used after being cooled to the temperature of liquid helium, a large current can flow without causing electrical resistance.

[0007]

THE INVENTION Problems to be Solved] To the compound superconducting wire produced by the conventional internal diffusion process, the above Sn-based metal material as is located in the center of the module, Nb ₃
The distance between Sn filaments is as narrow as about half as compared with the ordinary bronze method. Therefore, during the heat treatment of the precursor of the superconducting wire, the Nb-based metal filaments come into contact with each other, and the value of the effective filament diameter (d _eff ), which is the electrical characteristic of the superconducting wire (the sample shape is a cylinder, and the magnetization of the superconducting wire is Is given by d _eff = 3πΔM / 4μ ₀ Jc, where ΔM is the width of ΔM and the critical current density at that time is Jc. As a result, no problem occurs with respect to the DC current,
There is a problem that a large hysteresis loss occurs when a pulse current is applied, and stability is impaired due to heat generation of the superconducting coil.

In the internal diffusion method, since the Sn-based metal material is disposed at the center, a gradient occurs in the Sn concentration during the preliminary heat treatment for Sn diffusion. Therefore, the composition of the Nb ₃ Sn filament varies depending on the Sn concentration, and the n value (an index indicating the uniformity of the superconducting wire in the longitudinal direction, which is one of the superconducting characteristics; ⁿ in the equation represented by V∝In)
value. There is also a problem that the higher the n is, the better the superconductivity is).

The present invention has been made in order to solve such a problem, and the effective filament diameter of the superconducting wire is greatly reduced, the Jc of the superconducting wire is reduced to a minimum, and the n value is reduced. It is an object to provide an increased compound superconducting wire.

[0010]

A first method for manufacturing a compound superconducting wire according to the present invention comprises the steps of forming a Cu-based metal material and a first base metal material X forming an alloy layer with the Cu-based metal material. The laminated plate is first rolled, reduced in thickness and integrated, and this is mixed with a second base metal material Z.
(C) a step of filling a plurality of composite single-core wires obtained by winding the rod into a cylindrical container made of Cu to form a composite rod; and (B) drawing the composite rod to form a precursor of a superconducting wire. , (C) heat treating the precursor of the superconducting wire.

In a second method for producing a compound superconducting wire according to the present invention, a laminate of a Cu-based metal material and a first base metal material X forming an alloy layer with the Cu-based metal is first rolled and reduced in thickness. (C) filling a composite body integrated by the above-described steps into a Cu cylindrical container, providing a plurality of perforations in the composite, filling each hole with a second base metal material Z to form a composite rod; And (c) heat treating the precursor of the superconducting wire by drawing the composite rod.

In a third method for manufacturing a compound superconducting wire according to the present invention, a first perforation is provided at the center of a columnar Cu-based metal material, and a plurality of second perforations are provided around the first perforation. The second
Base metal material X that forms an alloy with Cu base metal in perforations
Filling the first perforation with a second base metal material Z to form a composite single core wire, and filling a plurality of the composite single core wires in a Cu cylindrical container to form a composite rod. (B) drawing the composite rod to form a precursor of a superconducting wire;
(C) heat treating the precursor of the superconducting wire.

In a fourth method for manufacturing a compound superconducting wire according to the present invention, the second base metal material Z is made of Ti, Ta, Hf, Mo,
It contains at least one member selected from the group consisting of Zr and V.

In a fifth method for manufacturing a compound superconducting wire according to the present invention, the first base metal material X contains at least one selected from the group consisting of Ti, In, Ge, Si and Mn. It was done.

In a sixth method for producing a compound superconducting wire according to the present invention, the Cu-based metal material contains at least one selected from the group consisting of Ti, In, Ge, Si and Mn. is there.

[0016]

The method for producing a compound superconducting wire of the present invention comprises the steps of:
Alternatively, since Ga is dispersed and arranged, the central Sn or Ga core is not required, and the space for burying the filament is increased by that amount, so that the filament interval is increased by about 30% than that obtained by the conventional internal diffusion method. The probability that the superconducting filaments are in contact with each other in the superconducting wire obtained after the heat treatment is significantly reduced, and the value of the effective filament diameter is greatly reduced. As a result, the hysteresis loss generated when the pulse current is supplied is greatly reduced, and the stability of the superconducting coil is improved.

Further, the diffusion distance of Sn or Ga becomes short and the content after diffusion becomes constant. As a result, the composition of the generated Nb ₃ Sn filament becomes uniform, and the n value, which is one of the superconducting characteristics, is reduced. improves. Also Sn or G
The time required for the preliminary heat treatment for a diffusion can be shortened, and the cost can be reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Regardless of the first and second aspects of the present invention, in the description of a superconducting wire and its precursor, a case where Nb and Sn are all used for simplicity will be described. However, not one by one otherwise specified in the following description, and V to Nb, Sn, it can be replaced with Ga, exactly the same superconducting wires be used a compound other than Nb ₃ Sn are obtained. Other than Nb ₃ Sn, V ₃ Ga is particularly practical.

Further, the "base A metal ..." used in the present invention.
The expression means that the substance is mainly composed of the metal A and may be pure or may have an additive. As a result of heat treatment or the like, an alloy or an intermetallic compound may be formed between the metal and another metal using the metal as a base metal, so the expression “A base metal...” Is used.

First, the first invention of the present case will be specifically described.

The Nb-Sn compound superconducting wire according to the first aspect of the present invention has a shape in which Nb ₃ Sn filaments are embedded in the bronze layer at intervals so as not to contact and couple with each other. Nb ₃ Sn filaments and mutually contact No such intervals, and, in order to fill the possible number of Nb ₃ Sn filaments are prone area Contact Nb base metal filaments, i.e. 300
In the boundary region of the ε-phase bronze layer generated by the preliminary heat treatment at a temperature of up to 600 ° C., the distance between the filaments of the Nb-based metal is made larger than in other regions, and the precursor of the superconducting wire is heat-treated.

In the preliminary heat treatment, when the precursor of the superconducting wire is heat-treated into a superconducting wire, it is previously heated to 300 to 600 ° C.
To diffuse the central Sn-based metal material into the surrounding Cu-based metal material to form a bronze layer of a Cu—Sn alloy. Heat treatment is performed subsequent to the preliminary heat treatment.

The Nb-Sn compound superconducting wire is obtained by a so-called internal diffusion method, and a single core wire obtained by drawing an Nb-based metal filament coated with a Cu-based metal material is converted into a billet. Filled and extruded to obtain a composite, or a perforated Cu plate is overlapped to form a block, and a single core wire is inserted into the perforated portion and extruded to obtain a composite, and the composite is obtained. Then, after punching the center of the composite, inserting a Sn-based metal rod, drawing a wire to obtain a precursor of the superconducting wire, and changing the precursor of the superconducting wire to 6
It is obtained by heat treatment at 100 to 800 ° C. for 100 to 200 hours. Further, a tubular composite is obtained by hollow extrusion or cold working of a billet filled with a single core wire, an Sn-based metal rod is inserted into the center of the tubular composite, and then wire drawing is performed to lead a superconducting wire. It may be a body. Thus C
Part or all of the Nb-based metal filament in the u-based metal material becomes Nb ₃ Sn, and as a result, N
A superconducting wire in which the b ₃ Sn filament is embedded is obtained.

In the superconducting wire according to the first aspect of the present invention, Nb _{3 in} the boundary region of the ε-phase bronze layer generated by the reaction of the central Sn-based metal material with the Cu-based metal material during the heat treatment.
Since the distance between the filaments is increased by making the filaments thin or coarsely arranged so that the Sn filaments do not come into contact with each other, excellent electrical properties can be obtained from the viewpoint of hysteresis loss.

The ε-phase bronze layer is a layer of Cu—Sn alloy generated in a temperature range of 300 to 600 ° C. when a central Sn-based metal material is diffused into a Cu-based metal material by heat treatment to form bronze. A kind of phase, whose chemical formula is C
It means an intermetallic compound represented by u ₃ Sn. The ε-phase bronze layer has a hard and brittle property compared to the α-phase bronze layer. When heat treatment is performed at 600 to 800 ° C., the ε phase is generated once and then disappears at the stage of the final heating temperature. The ε-phase is formed from the center toward the outer periphery, and the boundary between the ε-phase bronze layer and the Cu-based metal material varies depending on the amount of Sn. At a distance of about 50-70% of the radius (within the barrier layer). The boundary of the ε-phase bronze layer generated when the precursor of the superconducting wire is heated at 415 ° C. is located at a distance of 50 to 70% of the radius of the superconducting wire. At a temperature exceeding 600 ° C., the ε phase changes to the α phase and spreads over almost the entire surface.

The superconducting wire is formed during heat treatment of the precursor.
Nb_ThreeSn filaments easily contact each other
It is not clear why, but Nb-based metal filaments
Nb _ThreeWhen it becomes Sn, the volume of the Nb-based metal filament becomes
30% increase, filament moves during heating
Nb_ThreeSn filament
It is thought that there will be more opportunities for contact with the turtle. This movement
Is particularly large in the boundary region of the expansion of the ε-phase bronze layer.
No.

In order to prevent the Nb ₃ Sn filaments from contacting each other at the boundary region of the ε-phase bronze layer, the interval between the Nb-based metal filaments before the heat treatment should be 0.45 times or more the diameter of the Nb-based metal filaments. And more preferably 0.48 times or more. The above value is obtained experimentally. If the distance between the Nb-based metal filaments is less than the above value, the Jc of the superconducting wire after the heat treatment becomes large, but the contact of the Nb ₃ Sn filament often occurs. Therefore, d _eff, that is, the AC loss becomes large, and it is unsuitable for use as a pulse superconducting wire. For example, in the case of 0.38 times, d
_{The eff} becomes 500 μm, and it cannot be used as a superconducting wire for pulse.

The range in which the interval between the Nb-based metal filaments needs to be increased is the boundary region of the ε-phase bronze layer generated by the heat treatment, and the precursor of the superconducting wire is heat-treated at 415 ° C. from the center of the precursor of the superconducting wire. The radius is preferably 0.7 to 1.4 times the distance to the boundary of the ε-phase bronze layer formed at the time of the above, and particularly 0.9 to 1.
A range of two times is preferred. If the interval between the Nb-based metal filaments is increased beyond the above range, the number of the Nb-based metal filaments decreases, and as a result, Jc of the finally obtained superconducting wire becomes undesirably small. The distance to the boundary can be obtained by polishing a cross section of the superconducting wire and taking a photograph with an optical microscope or an electron microscope.

In order to obtain the precursor of the superconducting wire according to the first aspect of the present invention, there are the following methods, for example.

(1) Two types of single-core wires having different thicknesses of Cu in which an Nb wire is embedded in the center of a Cu-based metal material are produced, and a Cu-based metal rod is provided near the center of the Cu billet. Fill the periphery with a single core wire. At this time, the thick single-core wire is arranged in a region which is a boundary of the ε-phase bronze layer generated in the process of heat treatment for obtaining a superconducting wire, and the thin single-core wire is arranged inside and outside thereof.

The single core wire is obtained by inserting Nb rods of the same thickness into two types of Cu pipes having different wall thicknesses and stretching the same.

At this time, the diameters of two types of single core wires having different wall thicknesses (the diameter is a circular cross section, and the distance between opposite sides if a regular polygon).
Are stretched to be the same, the middle Nb wire becomes thinner in the case of a single core wire having a thick Cu. Therefore,
The spacing between Nb-based metal filaments in the boundary region of the ε-phase bronze layer is larger than that of a thin single core wire.

Further, when the stretching is performed, if the single core wire having a thicker Cu is made larger in diameter, and the single core wire having a thinner Cu is made smaller in diameter, a portion where the single core wire having a thick Cu is packed is formed. The distance between the Nb-based metal filaments becomes wider according to the difference in the thickness of Cu, and in any case, the distance between the Nb-based metal filaments can be increased.

After that, the Cu billet filled with the single core wire and the Cu-based metal rod is stretched to form a composite, and the Cu at the center is perforated, and the Sn-based metal rod is inserted.

C filled with the single core wire and a Cu-based metal rod
When the u billet is stretched, it is formed into a tubular composite by a method such as hollow extrusion or cold working.
A base metal material may be inserted. Thereafter, if necessary, the outside of the composite is covered with a diffusion barrier material for Sn, for example, Ta, and further covered with a stabilizing material and subjected to wire drawing to obtain a precursor of a superconducting wire. After that, the precursor of the superconducting wire is
Preliminary heat treatment at 0 to 600 ° C. causes the central Sn-based metal material to diffuse into the Cu-based metal around the Nb filament to produce bronze. After that another 600-8
Heat treatment is performed at 00 ° C. to obtain a superconducting wire.

The stabilizing material forms a layer that is not bronze even during heat treatment for obtaining a superconducting wire. By providing a layer made of the stabilizing material at the outermost portion of the superconducting wire, A more stable superconducting wire can be obtained for thermal and thermal treatments. As the stabilizing material, high-purity Al or the like can be used in addition to Cu. In order to prevent the bronzing, a S
It is preferable to provide a barrier layer that prevents diffusion of n. As a material for forming the barrier layer, Ta is preferable, but Nb, V and the like can also be used.

(2) When filling a single core wire into a Cu billet, the inside of the boundary of the ε-phase bronze layer is all filled with a Cu-based metal rod, a thick single core wire is provided immediately outside the boundary, and further outside the boundary. Is filled with a thin single-core wire, and the same processing is performed as in (1).

(3) An oxygen-free copper plate having a large number of holes is stacked and filled in a Cu billet, and Nb is inserted into the holes. The positions of the holes in the oxygen-free copper disk correspond to the positions where the single core wire is filled in the case of (1). At this time, the interval between the holes in the region that is the boundary of the ε-phase bronze layer is made wider than the other portions.
Thereafter, the same processing as in the case of (1) is performed.

The outside of the composite may be previously plated with Sn so that the amount of Sn at the center may be small.

The superconducting wire of the first invention comprises Ti, Ta, Hf, In, Ge, Si, Ga, Mo, as trace elements in the Nb ₃ Sn filament, as in the second invention described later.
At least one element selected from the group consisting of 2r, V and Mn may be contained in an amount of 0.01 to 5% by weight. The effect of containing each trace element is the same as in the case of the second invention.

There are the following methods for obtaining Nb ₃ Sn containing the trace elements.

(I) 0.01 to 10% by weight of Ti, I
An Sn alloy containing at least one selected from the group consisting of n, Ga, Ge, Si and Mn, or Sn obtained by mixing and molding the above metal powder is used. When the amount is less than 0.01% by weight, the effect is not recognized. When the amount is more than 10% by weight, the amount of Sn to be supplied becomes small, so that Nb3Sn produced is reduced.
The amount is reduced, and the characteristics are deteriorated.

(Ii) 0.01 to 5% by weight of Ti, Ta,
Mixing an Nb alloy containing at least one selected from the group consisting of Hf, Mo, Zr and V or the metal powder,
Use molded Nb. When the amount is less than 0.01% by weight, no effect is obtained. When the amount is more than 5% by weight, the amount of Nb is reduced, so that the amount of Nb3Sn produced is reduced and the characteristics are deteriorated.

(Iii) 0.01 to 5% by weight of Ti, I
Cu containing at least one selected from the group consisting of n, Ge, Si and Mn is used. The amount added is 0.01
If the amount is less than 5% by weight, the effect cannot be obtained. In addition, 0.01 to
When 1% by weight of Sn is contained, workability can be improved.

The precursor of the superconducting wire according to the second aspect of the present invention is obtained as follows.

(I) A Cu-based metal plate and a Sn-based metal plate are alternately stacked and rolled to form an integrated Cu—Sn composite, and the composite is vertically filled in an oxygen-free copper container. The filled container is extruded to form a Cu-Sn composite rod.
Next, a plurality of holes are drilled in the longitudinal direction of the composite rod, and an Nb-based metal rod is inserted into each of the holes to perform wire drawing.

(II) A large number of composite single-core wires obtained by coating a composite of Cu and Sn around an Nb-based metal rod are densely filled in an oxygen-free copper container, and the container is drawn. .

If necessary, it is preferable that the wire is covered with a barrier material for Sn before the wire drawing, and the wire is drawn with a pipe of a stabilizing material. The precursor of superconducting wire is
Preferably, the outermost layer is a layer of Cu or Al containing no Sn. The barrier material is a barrier that prevents Sn diffused during the heat treatment from reaching the outermost stabilizing material.

The proportion of Sn in the composite of Cu and Sn is preferably 1 to 99% by weight in the composite, and 13 to 20% by weight.
% By weight is particularly preferred. 1% by weight of Sn
If the amount is less than the above, the amount of Sn is insufficient, so that it is difficult to generate Nb ₃ Sn sufficiently. If the amount exceeds 99% by weight, the volume ratio of the Sn becomes too large, becomes too soft, and processing becomes difficult.

The composite single core wire is obtained by the following method.

(A) A Nb-based metal rod is inserted into a Cu-based metal pipe and extruded to form a single core wire, and the outer surface of the single core wire is Sn-plated to obtain a composite single core wire.

(B) An Sn rod is inserted into the perforated portion of the oxygen-free copper container having a plurality of holes perforated in its outer wall in the length direction, and an Nb-based metal rod is inserted into the center of the oxygen-free copper container. And
It is extruded to obtain a composite single core wire.

(C) A Cu-Sn composite plate integrated by rolling and sandwiching an Sn plate between two Cu plates, or a Cu plate having Sn plated on at least one side, is provided around the Nb-based metal bar by several steps. Twisted and extruded to obtain a composite single core wire.

Each N of the precursor of the superconducting wire of the second invention
The distance between the b-based metal filaments is 14/10 of the diameter so that the filaments do not contact each other during heat treatment.
It is necessary to be 0 or more, and it is particularly preferable that it is 30/100 or more. However, if the interval is too wide, the number of Nb ₃ Sn filaments in the superconducting wire decreases, and the value of Jc decreases. If the interval is too narrow, the d _eff value increases. Is desirable.

The superconducting wire according to the second invention is characterized in that Cu and S
processing time and 20 minutes to bronze the complex with
The temperature is appropriately selected from the range of 0 to 600 ° C., and the precursor of the superconducting wire is subjected to a preliminary heat treatment.
Was heated to 0 to 800 ° C. to about 100 to 200 hours is obtained by the Nb-based metal filaments and Nb ₃ Sn filaments. After the preliminary heat treatment, it may be cooled once and then heated again to 600 to 800 ° C.

The Nb ₃ Sn filament also contains Ti, Ta, Hf, In, Ge, Si, G
At least one element selected from the group consisting of a, Mo, Zr, V and Mn may be contained in an amount of 0.01 to 5% by weight.

As the trace elements, Ti, Ta, Hf, M
Nb ₃ S containing at least one of o, Zr and V
When n filaments are used, Jc on the high magnetic field side is improved.
In addition, when In or Ga is used, Jc on the low and medium magnetic field side is improved, and workability of the wire is improved. G
The addition of e, Si or Mn is effective in reducing AC loss.

There are the following methods for obtaining Nb ₃ Sn containing the trace elements.

(I) at least one member selected from the group consisting of Ti, In, Ga, Ge, Si and Mn is added to 0.0
Sn containing 1 to 10% by weight is used. If the content is less than 0.01% by weight, no effect is observed and 10% by weight
If the amount exceeds Nb, the amount of Sn to be supplied decreases, so that the amount of Nb3Sn generated decreases, resulting in deterioration of characteristics.

(Ii) at least one selected from the group consisting of Ti, Ta, Hf, Mo, Zr and V is 0.01%
Nb containing up to 5% by weight is used. When the content is less than 0.01% by weight, no effect is obtained.
Since the amount of b decreases, the amount of Nb ₃ Sn finally generated decreases, resulting in a deterioration in characteristics.

(Iii) Ti, In, Ge, Si and M
at least one selected from the group consisting of
Cu containing 5% by weight is used. When the content is less than 0.01% by weight, no effect is obtained. When the content is more than 5% by weight, processability is remarkably deteriorated. In addition, 0.01 to
When 1% by weight of Sn is contained, workability can be improved.

(Iv) Ti, In, Ge, Si, Mn, and N are formed on the surface of the composite comprising the Cu-based metal material and the Sn-based metal material.
At least one element selected from the group consisting of i and Sn is plated. In the case of Ti, the thin plate may be used by overlapping it with the plate of the composite.

(V) Ti, Ta,
At least one element selected from the group consisting of Hf, Mo, Zr and V is plated.

Hereinafter, a method of manufacturing a superconducting wire according to the present invention will be specifically described with reference to the drawings. The first to fourth embodiments are embodiments of the first invention, and the fifth to twelfth embodiments are embodiments of the second invention.

Embodiment 1 FIG. 1 is an explanatory view showing a cross-sectional structure of a composite before extrusion processing incorporated in a billet made of Cu. In FIG.
Reference numeral 1 denotes a composite, 2 denotes a billet, 13a and 13b denote Nb single-core wires described below, and 4a denotes a line made of a Cu-based metal material (hereinafter referred to as Cu-based metal wire).

First, two types of Nb single-core wires 13a and 13a to become Nb-based metal filaments as precursors of superconducting wires
3b was produced. That is, a round bar-shaped N having a diameter of 11 mm
b base metal rod is 11.8 mm in inner diameter and 11.8 mm outer diameter,
After being inserted into a 16.8 mm Cu-based metal pipe, drawing was performed to form a hexagonal line with a 4.2 mm gap between the opposite sides (13a in FIG. 1). Similarly, a round bar-shaped Nb-based metal rod having a diameter of 11 mm and an inner diameter and an outer diameter of 11.
From the 8 mm and 18.4 mm Cu-based metal pipes, a single core wire (thickness between opposite sides is 4.10 mm thicker than the single core wire 13 a).
A 2 mm hexagonal line) 13b was obtained.

The Nb single-core wires 13a and 13b and the hexagonal Cu-based metal wire 4a having a distance between opposite sides of 4.2 mm are connected to the Cu-based metal wire 4a from the center toward the outer periphery as shown in FIG.
a, seven layers of single-core wire 13a, three layers of single-core wire 13b,
Furthermore, the single core wire 13a was filled in the billet in a five-layer configuration (however, only one line is drawn from the center to the outer periphery in FIG. 1). The reason for choosing this configuration is that when the Sn-based metal material and the Cu-based metal wire arranged in the center are alloyed by heat treatment to form the ε-phase bronze layer, the boundary of the ε-phase bronze layer is shifted from the center to the second. Nb of the third and fourth layers
Since it is formed between the single core wires, the diameter of the Nb-based metal material filaments in the third to fifth layers is slightly reduced as described above to slightly widen the distance between the filaments after drawing, and Nb generated by heat treatment. _This is to prevent mutual contact of the ₃ Sn filaments.

After that, the billet is extruded, and the center of the extruded composite is pierced to form a billet.
After inserting the n-base metal rod, wire drawing was performed to obtain a composite wire. This composite wire is inserted into a Ta pipe, which is a barrier material for Sn diffusion, and further covered with a Cu pipe for stabilization, and then subjected to a secondary composite, followed by drawing to a wire diameter of 0.5 mm. Was performed.

The precursor of the superconducting wire manufactured as described above is subjected to a preliminary heat treatment, and then to a heat treatment to form Nb ₃ Sn on the Nb-based metal filament portion.
A -Sn superconducting wire was obtained. The temperature and time in this heat treatment need to be a temperature at which a superconductor is formed by a thermal diffusion reaction, and in the case of Nb ₃ Sn, it is 60 ° C.
100-200 hours at 0-800 ° C.

FIG. 2 is an explanatory view showing the cross-sectional structure of the heat-treated superconducting wire manufactured in this manner, where 9 is the superconducting wire after the heat treatment, 10 is the Nb ₃ Sn filament, 11
Is a low Sn concentration bronze, 7 is a barrier layer made of Ta, and 8 is a stabilizing layer made of Cu.

Since the Nb-based metal filament in the boundary region of the ε-phase bronze layer is slightly thinner than the other filaments, the distance between the filaments is slightly wider.

The low Sn concentration bronze refers to a bronze containing Sn having a lower content (about 3 to 10% by weight) than the Sn content (about 18 to 20% by weight) of the bronze once formed during the heat treatment. Sn diffuses by the heat treatment,
As a result of the generation of Nb ₃ Sn, the Sn content is reduced, and the region from the center of the superconducting wire to the Nb filament substantially corresponds to this.

The Jc of the superconducting wire obtained as described above
And d _eff measurements were made in liquid helium. As a result, with respect to Jc, in a magnetic field of B = 12T, Jc
= 820 A / mm ² was obtained. This value is Nb ₃ Sn compared to the characteristics of the conventional superconducting wire having a normal configuration.
Although the space factor of the Jc characteristic is reduced by 5%, the d _eff is 9 μm, which is about １ ／ of the previous value (36 μm). Therefore, comparing the two with the Jc / d _eff value as a comprehensive evaluation, it can be seen that a 3.8-fold improvement is achieved by the present invention.

Embodiment 2 FIG. 3 is an explanatory view showing another aspect of the structure of the cross section of the composite before extrusion processing incorporated in a billet made of Cu. 4b
Represents a Cu-based metal rod.

First, two types of Nb single-core wires 13c and 13d, which are Nb-based metal filaments as precursors of the superconducting wire, are used.
Was prepared as follows. That is, a round bar-shaped Nb-based metal rod having a diameter of 11 mm was used for the inner and outer diameters of 11.2 mm respectively.
After being inserted into 8 mm and 16.8 mm Cu-based metal pipes, wire drawing was performed to a wire diameter of 4.2 mm to produce a single core wire 13c having a thin Cu wall. In the same manner, C having an inner diameter and an outer diameter of 11.8 mm and 18.4 mm, respectively.
A round bar-shaped Nb-based metal rod having a diameter of 11 mm is inserted into a u-based metal pipe and wire-drawing is performed.
A thick single core wire 13d was obtained. In the second embodiment, by using two types of single-core wires having different thicknesses in which the thickness of Cu is changed, the filament interval in the boundary region of the ε phase in which contact between filaments particularly easily occurs is increased.

As shown in FIG. 3, the center has a diameter of 20 m.
m-based metal rod 4b, and then a single core wire 1
3c, two layers of single core wire 13d, and three layers of single core wire 13c
Was packed in a billet in a four-layer configuration (in FIG. 3, some single-core wires are omitted). The reason for selecting this configuration is the same as in the first embodiment. In this manner, C is added to the gap created by incorporating the round rod-shaped single core wire.
After inserting the thin wire of the u-based metal (the thin wire of the Cu-based metal is omitted in FIG. 3), extrusion was performed to obtain a composite. Thereafter, a central portion of the extruded composite was perforated, a Sn-based metal rod was inserted, and drawing was performed again to obtain a composite wire. The composite wire is inserted into a Ta pipe, which is a Sn diffusion barrier material, covered with a Cu pipe for stabilization, and subjected to secondary composite, and then drawn to a wire diameter of 0.5 mm to perform superconducting wire. Got a pioneer.

The precursor of the superconducting wire manufactured as described above was subjected to a preliminary heat treatment, followed by 600 to 750.
Heat treatment at 100 ° C. for 100 to 200 hours to obtain Nb—Sn
A superconducting wire was obtained. FIG. 4 is an explanatory view showing a cross-sectional configuration of the heat-treated superconducting wire manufactured as described above.
Is a superconducting wire after heat treatment, 10 is an Nb ₃ Sn filament, 11 is a low Sn concentration bronze layer, 7 is a Ta barrier layer,
Reference numeral 8 denotes a Cu stabilizing material.

The Jc of the superconducting wire obtained as described above
And d _eff were measured in liquid helium, and Jc was found to be Jc = 805 A / at a magnetic field of B = 12 T.
A value of mm ^{2 and} a value of 6 μm for d _eff were obtained. Therefore, Jc / d _eff as a comprehensive evaluation
Comparing the values with each other shows that the present invention achieves a 5.6-fold improvement over the conventional superconducting wire.

Embodiment 3 FIG. 5 is a perspective view showing a structure of a composite before extrusion processing incorporated in a billet made of Cu, wherein 1 is a composite before extrusion, 2 is a billet made of Cu, Reference numeral 13 denotes an Nb-based metal rod serving as a precursor filament of a superconducting wire, and 4c denotes a disk-shaped Cu-based metal material.

The disk-shaped Cu-based metal material 4c was produced as follows. That is, diameter 160mm, thickness 10m
309 mm of oxygen-free copper disc with a hole of 4.95 mm diameter
Each was perforated using an NC drilling machine. The hole at this time is
From the inside toward the outer periphery, the first and second layers were densely arranged, the second to fourth layers were coarsely arranged, and the fourth and fifth layers were densely arranged. The disc-shaped Cu-based metal material 4c is
0 sheets, outer diameter 180 mm, inner diameter 1
It was inserted into a 60 mm oxygen-free copper billet container. Next, an Nb-based metal rod 13 having a diameter of 4.9 mm was filled in the holes of the 30 stacked copper plates, and finally the inside was evacuated and the lid was welded to produce a composite billet. The insertion of the Nb-based metal rod into the oxygen-free copper disk was easy.

The composite billet was extruded, a central portion of the extruded composite was pierced, a Sn-based metal rod was inserted, and a drawing process was performed to obtain a composite wire. This was inserted into a pipe made of Ta, which is a Sn diffusion barrier material, covered with a Cu pipe for stabilization, and then subjected to secondary composite, followed by drawing to a wire diameter of 0.5 mm.

The precursor of the superconducting wire manufactured as described above was subjected to a preliminary heat treatment, followed by 600 to 750.
Heat treatment at 100 ° C. for 100 to 200 hours to obtain Nb—Sn
A superconducting wire was obtained. FIG. 6 is an explanatory view showing the cross-sectional structure of the heat-treated superconducting wire manufactured in this manner, where 9 is the superconducting wire after the heat treatment, 10 is the Nb ₃ Sn filament, 1
1 is a bronze having a low Sn concentration, 7 is a barrier layer made of Ta, 8
Is a stabilizing layer made of Cu.

Jc and d of the superconducting wire thus obtained
_{When eff} was measured in liquid helium, Jc was found to be Jc = 930 A / mm ^{2 at} a magnetic field of B = 12 T, and d _eff was also found to be 6 μm.
Therefore, comparing the two with the Jc / d _eff value as a comprehensive evaluation, the present invention shows that the conventional superconducting wire is 6.5 in comparison with the conventional superconducting wire.
It can be seen that a two-fold improvement is achieved.

[0084] As required specifications required of the fourth superconducting wire embodiment, there is a case where further improvement of d _eff properties are required than Jc properties.
In order to achieve this requirement, as a modification of the mode of the first embodiment, when the ε-phase bronze layer is generated during the heat treatment, the Nb-based metal filament exists only outside the ε-phase bronze layer boundary. So that a single core wire is arranged in advance. By doing so, contact and bonding between Nb ₃ Sn filaments can be suppressed, and d
The value of _eff can be effectively reduced.

FIG. 7 is an explanatory view showing the structure of the cross section of the composite before extrusion processing incorporated in a billet made of Cu.
Is a composite before extrusion, 2 is a billet made of Cu, 13
Reference numerals e and 13f denote hexagonal single-core Nb wires, and reference numeral 4a denotes a hexagonal Cu-based metal wire having a distance between opposite sides of 4.2 mm. The single-core wires 13e and 13f have an inner diameter and an outer diameter of 11.8 mm and 17.4 m, respectively, in order to increase the filament interval as compared with the case of the embodiment described in the first embodiment.
After inserting a round bar-shaped Nb-based metal rod having a diameter of 11 mm into a Cu pipe having an inner diameter and an outer diameter of 11.8 mm and an outer diameter of 19.3 mm at 13f, respectively, at 13f, wire drawing was performed. Is a hexagonal single-core wire having a distance between opposite sides of 4.2 mm.

As shown in FIG. 7, these Nb single-core wires have a billet structure in which seven layers of Cu-based metal wires 4a, three single-core wires 13f, and seven single-core wires 13e are arranged from the center to the outer periphery. Packed inside. In FIG. 7, only one line is shown from the center to the outer periphery of the single core wires 13e and 13f and the Cu-based metal rod 4a incorporated on the entire cross section. Thereafter, the billet was extruded, and then the center of the extruded composite was pierced to reduce the Ti to 1.5%.
After inserting the Sn alloy with a diameter of 14 mm added by weight%, wire drawing was performed to obtain a composite wire. After applying a Sn plating of about 30 μm thickness around the composite wire,
Was inserted into a Ta pipe, which is a diffusion barrier material, and covered with a Cu pipe for stabilization to form a secondary composite, and then drawn to a wire diameter of 0.5 mm. The reason for performing the Sn plating was to reduce the amount of the Sn-based metal material disposed in the central portion by dispersing Sn in the outer peripheral portion of the composite, and the Sn disposed in the central portion generated ε-phase bronze. This is because the region of the ε-phase bronze is sometimes reduced as much as possible.

The precursor of the superconducting wire thus produced was subjected to a preliminary heat treatment at 600 to 800 ° C. for 100 to 2 hours.
Heat treatment was performed for 00 hours to obtain an Nb-Sn-based superconducting wire. The heat treatment temperature is the temperature at which the superconductor is formed by thermal diffusion reaction, 600 in the case of Nb ₃ Sn
800 ° C. FIG. 8 is an explanatory view showing the cross-sectional structure of the heat-treated superconducting wire manufactured in this way, 9 is a superconducting wire after heat treatment, 10 is an Nb ₃ Sn filament,
11 is a low Sn concentration bronze, 7 is a barrier layer made of Ta,
Reference numeral 8 denotes a stabilizing layer made of Cu.

The obtained superconducting wire was measured for Jc and d _{eff in} liquid helium.

As a result, a value of Jc = 720 A / mm ² was obtained at a magnetic field of B = 12 T for Jc. This value is smaller than that of the conventional superconducting wire of the conventional configuration because the space factor of Nb ₃ Sn is smaller.
In the c-characteristic, it is reduced by 16%. However, d _eff was 4 μm, which is about 1/9 of the previous value (36 μm).
Was obtained. This value is superior to those of the first to third embodiments. Therefore, J as a comprehensive evaluation
Comparing the two with the c / d _eff value, 7.5 according to the present invention.
It can be seen that a two-fold improvement is achieved.

In the first to fourth embodiments, superconducting wires having a stabilizing layer represented by Cu and a diffusion barrier layer represented by Ta have been described as superconducting wires. You can omit it.

Fifth Embodiment FIG. 9 is an explanatory view showing a cross-sectional structure of a precursor of a superconducting wire according to the second invention, that is, a precursor of a superconducting wire before heat treatment which has been reduced in cross-section by stretching. In FIG.
21 is a precursor of a superconducting wire, 22 is a composite of a Cu-based metal material and a Sn-based metal material, and 23 is an Nb-based metal filament. FIG. 10 is an explanatory view showing the configuration of a superconducting wire cross section obtained by heat-treating the precursor of the superconducting wire, wherein 24 is a superconducting wire, 25 is an Nb ₃ Sn filament, 26 is Sn diffused by heat treatment, A bronze layer having a low Sn concentration as a result of reacting with Nb is shown.

The composite 22 of the Cu-based metal material and the Sn-based metal material was manufactured by the following method. First, a 15 mm thick plate obtained by alternately stacking and rolling nine 9 mm-thick Sn plates between 10 oxygen-free copper plates having a thickness of 2 mm was used to form a plate having a 180 mm outer diameter and a 160 mm inner diameter. The container was densely packed in a container of oxygen copper with the stacking surface vertical. Next, the inside was evacuated and the lid was welded, and the oxygen-free copper container was subjected to cold isostatic pressing to produce a rod-shaped composite having a diameter of 90 mm. Lastly, the oxygen-free copper in the outer peripheral portion of the rod-shaped composite was removed by performing outer peripheral cutting with a lathe, and the diameter was 8 mm.
A 0 mm cylindrical composite 22 was obtained.

The composite 22 having a diameter of 80 mm was
It was cut to 0 mm and 127 holes with a diameter of 4.1 mm were drilled. Next, an Nb base metal wire having a diameter of 4.0 mm and a length of 100 mm was inserted into the hole of the composite, the composite was placed in a container of oxygen-free copper having an outer diameter of 90 mm and an inner diameter of 80 mm, and the inside was evacuated. The composite billet was manufactured by subjecting the lid to electron beam welding. After the composite billet is subjected to cold isostatic pressing, the oxygen-free copper in the outer peripheral portion is removed by cutting the outer periphery with a lathe and then wire drawing is performed. A precursor of a 0.2 mm superconducting wire was obtained. The precursor of the obtained superconducting wire was subjected to a preliminary heat treatment at a temperature of 600 to 800 ° C and a temperature of 50 to 500 ° C.
A heat treatment was performed for 200 hours to form a Nb ₃ Sn superconductor on the Nb-based metal filament portion to obtain a superconducting wire.

When the Jc and d _eff of the obtained superconducting wire were measured in liquid helium, Jc was B = 1.
The value of 550 A / mm 2 in a 2T magnetic field is d
_{As for eff} , a value of 5 μm was obtained. In comparison with the Nb ₃ Sn superconducting wire obtained by the conventional internal diffusion method, when the two are compared by Jc / d _eff value as a comprehensive evaluation, a 4.4-fold improvement over the conventional superconducting wire is achieved by the present invention. It is understood that it is done.

Embodiment 6 FIG. 11 is an explanatory view showing an embodiment of the structure of a composite single-core wire serving as an Nb-based metal filament of a precursor of a superconducting wire according to the second invention. In FIG. 11, 23b is an Nb-based metal rod having 1% by weight of Ti, 28 is a Cu-based metal, 29
Indicates plating on the surface of the Cu-based metal material. The composite single core wire was manufactured as follows. That is, an Nb-based metal rod having a diameter of 11 mm to which 1% by weight of Ti has been added is inserted into Cu pipes having an inner diameter and an outer diameter of 11.8 mm and 18.4 mm, respectively. 4.2mm
Hexagonal single core wire. The surface of the single core wire was coated with Sn plating 7 to a thickness of about 100 μm to obtain a composite single core wire as shown in FIG.

The composite single core wire 1225 manufactured as described above
The book was filled in an oxygen-free copper billet having an outer diameter of 180 mm and an inner diameter of 160 mm, and evacuated and electron-beam welded on the lid to form a composite billet. Next, the composite billet was subjected to cold isostatic extrusion, followed by wire drawing to obtain a composite. The obtained composite is inserted into a Ta pipe which is a Sn diffusion barrier material, and C
Cover with u pipe to make secondary composite, wire drawing,
Twist processing was performed on the final diameter to obtain a precursor of a superconducting wire having a wire diameter of 0.3 mm.

FIG. 12 is an explanatory view showing the structure of the cross section of the precursor of the obtained superconducting wire. In FIG. 12, 21 is a precursor of a superconducting wire, 23b is an Nb-based metal filament having 1% by weight of Ti, 30 is a Ta barrier layer, 31 is a Cu layer for stabilization, 32 is a Cu-based metal material, and 33 is a Cu-based metal material. 4 shows Sn plating on the surface of a Cu-based metal material.

The precursor of the obtained superconducting wire was subjected to a preliminary heat treatment, followed by a heat treatment at 600 to 800 ° C. for 50 to 200 hours.
A superconducting wire was obtained by forming b ₃ Sn. FIG. 13 is an explanatory view showing the configuration of the cross section of the obtained superconducting wire.
Denotes a superconducting wire, 25 denotes an Nb ₃ Sn filament, 26 denotes a bronze having a low Sn concentration, 30 denotes a barrier layer made of Ta, and 31 denotes a Cu layer for stabilization.

Jc and d of the superconducting wire thus obtained
The measurement of _eff was performed in liquid helium. As a result, J
For c, 850 A / mm in a magnetic field of B = 12 T
A value of ^{2 and} a value of 3 μm for d _eff were obtained. In comparison with a Nb ₃ Sn superconducting wire containing Ti obtained by a conventional internal diffusion method, when both are compared by Jc / d _eff value as a comprehensive evaluation, the present invention shows that the conventional superconducting wire is 7.1 better than the conventional superconducting wire. It can be seen that a two-fold improvement is achieved.

Seventh Embodiment FIG. 14 is an explanatory diagram showing an example of a configuration of a composite single core wire before section reduction processing used for manufacturing a precursor of a superconducting wire according to the second invention. In FIG. 14, 32 indicates a Cu-based metal material, 23a indicates an Nb-based metal bar, and 34 indicates a Sn-based metal bar containing 7% by weight of In. The composite single core wire was manufactured as follows.

That is, first, as shown in FIG. 14, an outer diameter of 25 mm and an inner diameter of 14 m provided with eight 3.5 mm diameter holes.
13.9 m diameter in the center of an oxygen-free copper billet container
m of Nb-based metal rod was inserted, and eight Sn-based metal rods having a diameter of 3.4 mm and containing 7% by weight of In were inserted into each of the peripheral holes. After the inside of the billet container was evacuated and the lid was subjected to electron beam welding, cold isostatic pressing was performed, followed by wire drawing to obtain a hexagonal composite single core wire having a 4.2 mm opposite side. Was.

The 1225 composite single-core wires were used in Embodiment 6
After filling in the same billet made of Cu, the inside was evacuated and the lid was electron beam welded. The composite billet was subjected to cold isostatic extrusion and then drawn to obtain a composite wire. Next, the composite wire was inserted into a Ta pipe, which is a Sn diffusion barrier material, and further covered with a Cu pipe for stabilization to form a secondary composite, followed by wire drawing. Thereafter, this wire was subjected to a twisting process at a final diameter to obtain a precursor of a superconducting wire having a wire diameter of 0.3 mm.

FIG. 15 is an explanatory view showing the configuration of a cross section of the precursor of the superconducting wire. In the figure, 21 is a precursor of a superconducting wire,
23a is an Nb-based metal filament, 30 is a Ta barrier layer,
31 is a Cu layer for stabilization, 32 is a Cu-based metal material, 3
Reference numeral 4 denotes a Sn-based metal material containing 7% by weight of In.

The precursor of the obtained superconducting wire is subjected to a preliminary heat treatment, followed by a heat treatment at 600 to 800 ° C. for 50 to 20 hours.
_A 3Sn superconductor was formed to obtain a superconducting wire. The cross-sectional shape of the obtained superconducting wire was the same as in FIG.

The Jc and d _eff of the obtained superconducting wire were measured in liquid helium. As a result, a value of 633 A / mm ² was obtained for Jc in a magnetic field of B = 12 T, and a value of 3 μm was obtained for d _eff . Nb containing In obtained by a conventional internal diffusion method
_In comparison with a 3Sn superconducting wire, when both are compared by Jc / d _eff value as a comprehensive evaluation, it is understood that the present invention achieves a 7.0-fold improvement over the conventional superconducting wire.

Eighth Embodiment FIG. 16 is an explanatory view showing the configuration of a composite single core wire before section reduction used for manufacturing a superconducting wire according to the second invention of the present invention. A composite of Cu and Sn contained therein, and 23a indicates an Nb-based metal rod.

The composite 22b is obtained by stacking a 1 mm-thick Sn plate between two 1 mm-thick Cu plates containing 1% by weight of Ti, rolling and integrating them into a 1 mm-thick thin plate. It is. This thin plate-shaped composite 22b is 140m long and wide.
Cut to size of mx 1000mm, diameter is 10m
m, after winding in a wrapped shape around a round Nb-based metal rod having a length of 1000 mm, the inner diameter and the outer diameter are each 1
It was inserted into 8 mm and 19 mm oxygen free copper pipes 35. Next, the pipe 35 was subjected to wire drawing to obtain a hexagonal composite single core wire having an opposite side of 4.2 mm.

The above-mentioned 1225 composite single-core wires are formed with an outer diameter of 180 m.
After filling into a billet made of oxygen-free copper having a diameter of 160 mm and an inner diameter of 160 mm, the inside of the billet was evacuated, and the lid was subjected to electron beam welding. Next, this billet was subjected to cold isostatic extrusion, followed by wire drawing to obtain a composite wire. The composite wire was inserted into a Ta pipe, which is a Sn diffusion barrier material, covered with a Cu pipe for stabilization to form a second composite, and wire drawing was performed. This was subjected to twist processing at the final diameter to obtain a precursor of a superconducting wire having a wire diameter of 0.3 mm.

FIG. 17 is an explanatory view showing the structure of a cross section of the precursor of the superconducting wire. In the figure, 22b is a composite of Cu and Sn containing 1% by weight of Ti, 23a is an Nb-based metal filament, 30a is Denotes a Ta barrier layer, 31 denotes Cu as a stabilizing material, and 32 denotes a Cu-based metal material.

The precursor of the obtained superconducting wire was subjected to a preliminary heat treatment, followed by a heat treatment at 600 to 800 ° C. for 50 to 200 hours.
A superconducting wire was obtained by forming a b ₃ Sn superconductor. The cross-sectional shape of the superconducting wire was the same as in FIG.

The Jc and d _eff of the obtained superconducting wire were measured in liquid helium. As a result, a value of 900 A / mm ² was obtained for Jc in a magnetic field of B = 12 T, and a value of 3 μm was obtained for d _eff . Therefore, in comparison with the Nb ₃ Sn superconducting wire obtained by containing the conventional internal diffusion method Ti, when comparing both with Jc / d _eff value as a comprehensive evaluation, according to the present invention, it is 7 times better than the conventional superconducting wire. It can be seen that a 0.5-fold improvement is achieved.

Ninth Embodiment FIG. 18 is an explanatory view showing the structure of a composite single core wire before the cross-section reduction processing, which is used for manufacturing the superconducting wire of the second invention. In FIG. 18, reference numeral 22c denotes a composite made of a Cu-based metal material whose surface is plated with Sn, 23c denotes an Nb-based metal rod whose surface is plated with Ti, and 35 denotes an oxygen-free copper pipe.

First, the surface of an Nb-based metal rod having a diameter of 10 mm, which becomes a filament of a superconducting wire, is electroplated to form a T
i was electrodeposited at about 45 μm. Next, about 200mm in width,
The surface of the oxygen-free copper plate having a thickness of 0.5 mm was plated with Sn about 0.1 mm to obtain a Cu-Sn composite 22c. The composite was wound into a five-layer winding using a Ti-plated Nb-based metal rod 23c as a core metal, inserted into an oxygen-free copper pipe having an inner diameter and an outer diameter of 18 × 19 mm, and then expanded. The wire was processed to obtain a hexagonal composite single core wire having a 4.2 mm opposite side.

The obtained 1225 composite single-core wires were filled in the same billet made of Cu as in the sixth embodiment, evacuated and electron-beam welded to the lid, and subjected to cold isostatic pressing and cold elongation. The wire was processed to obtain a composite wire. The composite wire was further drawn and twisted with a final diameter to obtain a precursor of a superconducting wire having a wire diameter of 0.3 mm.

FIG. 19 is an explanatory view showing the structure of a cross section of the precursor of the superconducting wire. In FIG. 19, reference numeral 22c denotes a Cu composite whose surface is plated with Sn, 23c denotes an Nb-based metal filament whose surface is plated with Ti, 31 denotes Cu as a stabilizer, and 32 denotes a Cu-based metal material.

The precursor of the obtained superconducting wire was subjected to a preliminary heat treatment, followed by a heat treatment at 600 to 800 ° C. for 50 to 200 hours.
A superconducting wire was obtained by forming a b ₃ Sn superconductor. The cross-sectional shape of the superconducting wire was the same as in FIG.

The obtained superconducting wire was subjected to Jc in liquid helium.
And d _eff were measured. As a result, a value of 900 A / mm ² was obtained for Jc in a magnetic field of B = 12 T, and a value of 3 μm was obtained for d _eff . Therefore, in comparison with the Nb ₃ Sn superconducting wire containing Ti obtained by the conventional internal diffusion method, when both are compared with the Jc / d _eff value as a comprehensive evaluation, the present invention shows that the Jc / d _eff value is 7 times higher than that of the conventional superconducting wire. It can be seen that a 0.5-fold improvement is achieved.

Tenth Embodiment FIG. 20 is an explanatory diagram showing a cross-sectional configuration of a composite single core wire before a cross-section reduction process, which is used for manufacturing the superconducting wire of the second invention. In the figure, reference numeral 22c denotes C whose both surfaces are plated with Sn.
Cu-Sn composite composed of a u-based metal material, 23a is an Nb-based metal rod, 35 is a Cu-based metal pipe, 36 is a Ti thin plate sandwiched between the Cu-Sn composite 22c and the Nb-based metal rod 23a. Show.

First, a single-core wire 1 serving as a filament of a superconducting wire was manufactured as follows. As in the ninth embodiment,
The surface of an oxygen-free copper plate having a width of about 200 mm and a thickness of 0.5 mm is subjected to Sn plating about 0.1 mm to form a Cu—Sn composite 22.
a was obtained. The composite 22a has a thickness of 0.05 mm and a width of about 3
A thin Ti plate 36 having a thickness of 0 mm was stacked, and a round bar-shaped Nb-based metal bar 23a having a diameter of 10 mm was used as a core metal, and was wound in a shape of about five layers. However, since the Ti thin film had a width of only about 30 mm, only one layer could be wound around the round Nb-based metal rod.

The inner and outer diameters are 18 ×, respectively.
After being inserted into a 19 mm oxygen-free copper pipe 35, wire drawing was performed to obtain a hexagonal composite single core wire having a 4.2 mm opposite side.

The above-mentioned 1225 composite single-core wires are used in the sixth embodiment.
After filling in a Cu billet similar to that described above, vacuum evacuation and electron beam welding of the lid are performed, cold isostatic pressing is performed, then wire drawing is performed, and then Ta, which is a Sn diffusion barrier material, is used. It was inserted into a pipe, covered with a Cu pipe for stabilization, and secondary composited. The obtained secondary composite material was subjected to wire drawing and twisting with a final diameter to obtain a precursor of a superconducting wire having a wire diameter of 0.3 mm.

[0122] The the precursor of the superconducting wire, and was heat-treated for 50 to 200 hours at subsequently 600 to 800 ° C. to preliminary heat treatment, Nb ₃ to Nb-based metal filaments moiety
A superconducting wire was obtained by forming a Sn superconductor. The cross-sectional shape of the superconducting wire was the same as in FIG.

The Jc and d _eff of the obtained superconducting wire were measured in liquid helium. As a result, a value of 900 A / mm ² was obtained for Jc in a magnetic field of B = 12 T, and a value of 3 μm was obtained for d _eff . T
Compared with the conventional internal diffusion method Nb3Sn superconducting wire to which i is added by Jc / d _eff value as a comprehensive evaluation, according to the present invention, it is 7.
It can be seen that a five-fold improvement is achieved.

Eleventh Embodiment FIG. 21 is an explanatory view showing the structure of a composite single core wire before section reduction processing used for manufacturing the superconducting wire of the second invention. In the figure, 22d is Cu whose surface is plated with pure Ti.
-Sn composite, 23a is an Nb-based metal rod, and 35 is a Cu-based metal pipe.

First, similarly to the eighth embodiment, a thickness of 1 mm
A 1 mm thick Sn plate is stacked and rolled between two Cu plates, and integrated to produce a 1 mm thick thin plate, and the thin plate is cut into a size of 140 mm × 1000 mm in length and width. Then, about 10 μm of Ti plating was applied to one side of the thin plate to obtain a composite 22d. The composite 22d has a diameter of 10 mm,
After winding in a wrapped shape around a round Nb-based metal material bar 23a having a length of 1000 mm, the wire is inserted into an oxygen-free copper pipe 35 having an inner diameter and an outer diameter of 18 mm and 19 mm, respectively, and drawn. To obtain a hexagonal composite single core wire having a length of 4.2 mm.

The obtained 1225 single-core composite wires were filled in a Cu billet similar to that of the sixth embodiment, evacuated, subjected to electron beam welding of the lid, and then subjected to cold hydrostatic extrusion. The composite wire was obtained by wire drawing.
The composite wire is inserted into a Ta pipe, which is a Sn diffusion barrier material, covered with a Cu pipe for stabilization to perform a secondary composite, and then twisted to a final diameter of 0.3 mm. Of superconducting wire was obtained. The configuration of the cross section of the precursor of the superconducting wire was the same as in FIG.

The precursor of the obtained superconducting wire was subjected to a preliminary heat treatment, followed by a heat treatment at 600 to 800 ° C. for 50 to 200 hours.
A superconducting wire was obtained by forming a b ₃ Sn superconductor. The cross-sectional shape of the superconducting wire was the same as in FIG.

The Jc and d of the superconducting wire thus obtained were
The measurement of _eff was performed in liquid helium. As a result, J
For c, 910 A / mm in a magnetic field of B = 12 T
A value of ^{2 and} a value of 3 μm for d _eff were obtained. Therefore, obtained by the conventional internal diffusion method,
In comparison with the Nb ₃ Sn superconducting wire containing Ti,
Comparing the Jc / d _eff values as a comprehensive evaluation shows that the present invention achieves a 7.6-fold improvement over the conventional superconducting wire.

Twelfth Embodiment As a required specification for a superconducting wire, there may be a case where the Jc characteristic is required to be more improved than the d _eff characteristic. To fulfill this request,
Although some bonding between Nb ₃ Sn filaments occurs after the heat treatment and the d _eff characteristics increase, the Jc characteristics can be improved by arranging the filaments more closely than in the previous embodiments. .

FIG. 22 is an explanatory view showing the structure of a composite single-core wire before the cross-section reduction processing, which is used for manufacturing the superconducting wire of the second invention. In the figure, 22a is a composite of Cu and Sn, 23d is an Nb-based metal rod containing 1% by weight of Ta, 3
Reference numeral 6 denotes a Cu-based alloy pipe containing 3% by weight of Ti.

First, as in the eighth embodiment, a thickness of 1 mm
A 1.5 mm thick Sn plate was overlapped between two Cu plates, rolled, and integrated to produce a 1 mm thick thin plate. This thin plate is cut into a size of 150 mm × 1000 mm in length × width, containing 1% by weight of Ta, and having a diameter of 12.7 m.
m, round bar-shaped Nb-based metal round bar 23 having a length of 1000 mm
After wrapping around d, the inner and outer diameters containing 3% by weight of Ti are 19 mm and 20 mm, respectively.
In a Cu pipe 36, and wire drawing was performed to obtain a hexagonal composite single-core wire having a 4.2 mm opposite side.

The composite single core wire 122 thus manufactured
Five were filled in the same billet made of Cu as in the sixth embodiment, the inside was evacuated, and the lid was subjected to electron beam welding to form a composite billet. The composite billet was cold-extruded in an isostatic pressure and drawn to obtain a composite wire. This composite wire is inserted into a Ta pipe, which is a Sn diffusion barrier material, covered with a Cu pipe for stabilization, and then subjected to a secondary composite. Of superconducting wire was obtained. The configuration of the cross section of the precursor of the superconducting wire was the same as in FIG. Regarding the precursor of the obtained superconducting wire, 50 to 20 at 600 to 800 ° C.
Heat treatment was performed for 0 hour to form a Nb ₃ Sn superconductor on the Nb-based metal filament portion, thereby obtaining a superconducting wire. The cross-sectional shape of the superconducting wire after the heat treatment was the same as in FIG.

The Jc and d _eff of the obtained superconducting wire were measured in liquid helium. As a result, a value of 1250 A / mm ² was obtained for Jc at a magnetic field of B = 12 T, and a value of 56 was obtained for the n value. Therefore, in comparison with the Ti-containing Nb ₃ Sn superconducting wire obtained by the conventional internal diffusion method, according to the present invention, J
It can be seen that about 40% improvement is achieved with c and about twice improvement with n value.

As described in the fifth to twelfth embodiments, the distributed Sn diffusion method is more effective than the conventional internal diffusion method.
In the overall Jc / d _eff value, the superconducting property is about 5
Among them, the superconducting wire having a configuration in which the composite of Cu and Sn described in Embodiment 8 and the following is wound around a round bar-shaped Nb filament in the shape of a wrapped wire has Jc, d _eff ,
The improvement of n-value, which is one of the indices indicating the superconductivity, was remarkable, and the workability of the wire was particularly excellent. It is considered that the reason is that, since the composite of Cu and Sn is wound in a wrapping shape, the dispersion of Sn is improved, and the composition deviation of Nb3Sn generated in the filament is suppressed, leading to an improvement in the characteristics.

In Embodiments 5 to 12, superconducting wires having a stabilizing material represented by Cu and a diffusion barrier material represented by Ta have been described as superconducting wires. Superconducting wire is high-purity Al as a stabilizer,
It is also effective when Nb or V is used as the diffusion barrier material. Further, the use of the diffusion barrier material and the stabilizing material can be omitted.

Further, in the fifth to twelfth embodiments, the example in which the composite wire is formed into a single secondary composite has been described. What is necessary is just to fill and make a secondary composite, and to process a cross section reduction.

As described earlier, the same result can be obtained by replacing Nb and V with Sn and Ga as described in this specification.

[0138]

According to the method for producing a compound superconducting wire of the present invention, the composite material of Sn or Ga and Cu
By dispersing the filaments around the b- or V-based metal filaments, the filament spacing can be increased by about 30% compared to the internal diffusion method, so that the Nb ₃ Sn filaments in the superconducting wire after heat treatment come into contact with each other. The probability of bonding is significantly reduced, and the value of the effective filament diameter can be greatly reduced. As a result, there is an effect that the hysteresis loss generated when the pulse current is applied is greatly reduced, and the stability of the superconducting coil is improved. Further, since the diffusion distance of Sn can be short, the composition of Nb ₃ Sn generated in each filament becomes uniform, and there is an effect that Jc and n value are improved. Further, since the time required for the preliminary heat treatment for Sn diffusion can be reduced, there is also an effect that cost reduction is excellent.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a cross-sectional configuration of a composite before extrusion processing of an embodiment of a superconducting wire of the first invention.

FIG. 2 is an explanatory diagram showing a cross-sectional configuration of an embodiment of the superconducting wire of the first invention.

FIG. 3 is an explanatory diagram showing a cross-sectional configuration of a composite before extrusion processing of one embodiment of the superconducting wire of the first invention.

FIG. 4 is an explanatory diagram showing a cross-sectional configuration of an embodiment of the superconducting wire of the first invention.

FIG. 5 is a perspective view of the composite before extrusion of the embodiment of the superconducting wire of the first invention.

FIG. 6 is an explanatory diagram showing a cross-sectional configuration of an embodiment of the superconducting wire of the first invention.

FIG. 7 is an explanatory diagram showing a cross-sectional configuration of a composite before extrusion processing of the embodiment of the superconducting wire of the first invention.

FIG. 8 is an explanatory diagram showing a cross-sectional configuration of an embodiment of the superconducting wire of the first invention.

FIG. 9 is an explanatory view showing a cross section of an embodiment of the superconducting wire precursor of the second invention.

FIG. 10 is an explanatory view showing a cross section of one embodiment of the compound superconducting wire of the second invention.

FIG. 11 is an explanatory view showing one embodiment of a composite single core wire used for manufacturing a precursor of a superconducting wire of the second invention.

FIG. 12 is an explanatory view showing a cross section of another embodiment of the precursor of the superconducting wire of the second invention.

FIG. 13 is an explanatory view showing a cross section of another embodiment of the compound superconducting wire of the second invention.

FIG. 14 is an explanatory view showing a cross section of another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire of the second invention.

FIG. 15 is an explanatory view showing a cross section of another embodiment of the precursor of the superconducting wire of the second invention.

FIG. 16 is an explanatory view showing another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire of the second invention.

FIG. 17 is an explanatory view showing a cross section of another embodiment of the precursor of the superconducting wire of the second invention.

FIG. 18 is an explanatory view showing another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire of the second invention.

FIG. 19 is an explanatory view showing a cross section of another embodiment of the precursor of the superconducting wire of the second invention.

FIG. 20 is an explanatory view showing a cross section of another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire of the second invention.

FIG. 21 is an explanatory view showing another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire according to the second invention.

FIG. 22 is an explanatory view showing another embodiment of the composite single core wire used for manufacturing the precursor of the superconducting wire of the second invention.

FIG. 23 is an explanatory sectional view showing a section of a precursor of a conventional superconducting wire.

FIG. 24 is an explanatory view showing a cross section of a conventional superconducting wire.

[Explanation of symbols]

1 Composite, 9 superconducting wire, 10 Nb ₃ Sn filament, 11 low Sn concentration bronze, 13a Cu is thin single core wire, 13b Cu is thick single core wire, 21 superconducting wire precursor, 22 Cu base metal material and Composite with Sn-based metal material, 23 Nb-based metal filament.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C22F 1/00 691 C22F 1/00 691C (72) Inventor Hiroko Hikuma 2-3-2 Marunouchi, Chiyoda-ku, Tokyo No. Mitsubishi Electric Co., Ltd. (72) Inventor Takayuki Nagai 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (72) Hideko Uchikawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation

Claims (6)

[Claims] (A1) A laminate of a Cu-based metal material and a first base metal material X forming an alloy layer with the Cu-based metal material is first rolled, reduced in thickness and integrated, and Second base metal material Z
(C) a step of filling a plurality of composite single-core wires obtained by winding the rod into a cylindrical container made of Cu to form a composite rod; and (B) drawing the composite rod to form a precursor of a superconducting wire. And (C) a step of heat-treating the precursor of the superconducting wire. 2. (A2) A laminate of a Cu-base metal material and a first base metal material X forming an alloy layer with the Cu-base metal is first rolled, reduced in thickness and integrated to form a composite. Filling a cylindrical container, providing a plurality of perforations in the composite, filling each hole with a second base metal material Z to form a composite rod, and (B) drawing the composite rod. A superconducting wire precursor,
(C) a step of heat-treating the precursor of the superconducting wire. (A3) A first perforation is provided at the center of the columnar Cu-based metal material, a plurality of second perforations are provided around the first perforation, and the second perforation is provided with a Cu-based metal. A first base metal material X forming an alloy with the first base material is filled, a second base metal material Z is filled in the first perforation to form a composite single core wire, and the composite single core wire is placed in a Cu cylindrical container. A step of forming a composite rod by filling a plurality of the superconducting rods; (B) a step of drawing the composite rod to form a precursor of a superconducting wire; and (C) a step of heat-treating the precursor of the superconducting wire. Of manufacturing a superconducting wire provided. 4. The method according to claim 1, wherein the second base metal material Z is Ti, Ta, H
4. The method for producing a superconducting wire according to claim 1, comprising at least one selected from the group consisting of f, Mo, Zr and V. 5. The method according to claim 1, wherein the first base metal material X is Ti, In, G
4. The method for producing a superconducting wire according to claim 1, comprising at least one selected from the group consisting of e, Si and Mn. 6. The method according to claim 1, wherein the Cu-based metal material is Ti, In, Ge,
The method for producing a superconducting wire according to claim 1, 2 or 3, comprising at least one selected from the group consisting of Si and Mn.