JPS62252012A - Compound superconductor wire material and manufacture of thesame - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to improvements in internally stabilized in-situ compound superconducting wires and methods for producing the same.

(Prior Art) Generally, as a method for manufacturing an in-situ compound superconducting wire, first a compound superconducting wire such as Nb or Sn is used.

It is an A3B type compound such as V, Ga, etc., and it is made by dissolving and rapidly cooling A3B type compounds such as Nb, V, etc. and IJ gas such as Cu.
A mixed crystal containing a fine mixture of metal and C4L is called an in-situ ingot. When this ingot is subjected to area reduction processing, A surrounded by Cu
A group of elongated metal fibers is formed. When such a composite wire is plated with a B metal such as tin or gallium and heated, it is diffused to form an A3B compound superconductor.

In addition to copper, the matrix mentioned above is A, which has a high purity.
7. Ag etc. As the plating metal, single metals such as Cu and Ni or alloys such as Cu-8n bronze are used.

Further, the cross-sectional shape of the wire may be circular, rectangular, or tape-shaped.

Conventional in-situ compound super% conductive wires have a diffusion shielding layer 2 provided on the outer periphery of a wire rod, that is, a stabilizing metal 1, as shown in FIG. 1, and further coated with an in-situ wire rod 3 of Cu-B/A, B on the outside. Or as shown in Figure 2 (Cu-I
3/C on the outer periphery of the in-situ wire 3 made of A3B alloy
A stabilizing metal layer 4 made of U plating is provided and heated, or a stabilizing metal layer 6 made of Cu tape is placed on both sides of an in-situ tape 3 made of Cu-B/A3B alloy with a solder layer 5 interposed therebetween as shown in FIG. There are some that have.

However, the one shown in Figure 1 requires mechanical protection because the in-situ compound is on the surface. Also, since the cooling conditions are determined by the surface condition, it is likely to become unstable. Furthermore, the wire rod shown in FIG. 2 cannot be made to have a large diameter because it relies on cooling from the surface. Therefore, the current capacity is small. In addition, in the case of the one shown in FIG. 3, solder voids are easily generated, the stabilizing metal does not work effectively, and the cooling of the center of the in-situ wire portion is controlled by its thickness, so that the current capacity cannot be increased.

(Problems to be Solved by the Invention) The present invention relates to an improvement in a method for manufacturing an internally stabilized in-situ compound@i conductive wire, and aims to obtain an in-situ compound superconducting wire having a predetermined shape.

(Means for Solving the Problems) The present invention is characterized in that, in an in-situ A3B compound superconducting wire, a stabilizing metal is disposed inside and on the outer periphery of the wire.

In addition, the method of the present invention includes forming at least one hole inside the in-situ composite material, and inserting a stabilizing metal or a stabilizing metal coated with a diffusion barrier into the hole in producing an in-situ A3B compound superconducting wire. A first step of plating the surface, a second step of applying metal plating to the surface, and a third step of extruding.
After reducing the area of the extruded material, plate the B joint, and add A3 inside the wire.
This method is characterized by comprising a fourth step of forming a B compound, and a fifth step of adding a stabilizing metal in contact with the outer surface of the wire.

(Example) Example (]) As shown in Fig. 4, an in-situ Cu/V ingot was produced by arc melting, and the non-uniform parts of the surface were externally milled to form a homogeneous Cu/V composite 3 (40ψ ×1 s o, g
). A hole of 16ψ was drilled in the center of the stabilized copper 1 (15,8ψ×1
35A) was inserted, and a Cu lid was sealed on the upper end surface with an electron beam in a vacuum. This billet was plated with Cu to a thickness of about 30 μm, heated to 700°C, and then extruded 101
After reducing the area to 1ψ and further reducing the area, it was rolled to
The tape was 11×5u. Ga was applied to this tape in vacuum.
Plating was applied and diffusion heat treatment was performed at 500° C. for 7 days to form V and Ga within the tape. After that, about 1
A compound superconducting wire of the present invention was prepared by applying Cu plating 4 with a thickness of 5 μm.

Comparative example (1) C without a hole in the center in Example (1)
All Example (1) except that u/V complex was used.
A comparative compound superconducting wire was prepared in the same manner as above.

Comparative Example (2) The coil of Comparative Example (1) was returned to its original position, and copper tape of approximately 8 μm was attached to both sides of the tape by soldering to obtain a comparative compound superconducting wire.

Regarding the thus obtained compound superconducting wire of the present invention and comparative example compound superconducting wire, these tapes were each 30 m long.
A one-time energization experiment was conducted using a pancake-shaped sample. The results are shown in Table 1.

As is clear from Table 1, the product of the present invention was able to conduct electricity up to 15 T in a completely stable manner. However, in the comparative example, a severe 7-lux jump phenomenon occurred at 7T and 1oT, indicating that the tape was unstable.

Note that in Comparative Example (2), 7T was lower than in Comparative Example (1).
However, no major improvement was observed.

Example (2) An in-situ Cu/V ingot was produced by arc melting, and the non-uniform parts of the surface were externally milled to create a homogeneous Cu/V ingot.
I got a composite material (409X15 (1#).In the center of this
A hole of No. 9 was drilled, and a stabilized copper (14ψX13 (1#)) covered with Nb with a thickness of lu was inserted into the hole, and a Cu lid was welded to the upper end surface using an electron beam in a vacuum. After sealing, Cu
/ The outer periphery of the V composite material 1 was plated with 0Cu to a thickness of about 30 μm to obtain vinylet.

This billet was heated to 700°C in an Ar atmosphere and extruded into a 10ψ wire rod, which was further reduced in area to 0.2
I got 9 wire rods. After that, the surface was treated with HNO at a concentration of 20-
, and the Cu coating layer was removed by washing with an aqueous solution.

This wire was plated with Ga in a vacuum and heated to 500°C for 7
The in-situ V of the present invention is produced by performing a day-long diffusion heat treatment to form V and Ga inside the wire, and then applying Ga plating to the outside thereof.
Ga superconducting wire was obtained.

The thus obtained superconducting wire of the present invention was placed in liquid He (4.2K).
As a result of measuring the critical current density, it is 1.8 in a magnetic field of 10T.
It showed excellent performance of X 10' A/cd. In addition, the space factor of the stabilized copper with respect to the total cross-sectional area of the wire was measured. That is, as a result of dissolving each component in HNO and an aqueous solution and taking specific gravity into consideration, the result remained within a range of ±2% of the target 12%.

Example (3) The wire rod of 109) extruded as in Example (2) was subjected to area reduction processing to make a 3ψ wire rod, and its surface was reduced to 20
Washing with HNO and aqueous solution to remove edge waves, annealing in a vacuum atmosphere at 950°C for 1 hour, twisting with a pitch of 10u, and switching to rolling with rolls.
．． A tape of 15 t x 5.3 was obtained. Thereafter, both end faces were processed to have a width of 5.0 mm, Ga plating was applied in a vacuum, and diffusion heat treatment was performed at 500°C for 7 days to form the in-situ V, Ga superconductor tape of the present invention. I got it.

The thus obtained superconducting tape of the present invention was placed in liquid He (4,2
K), Results of measuring critical current density under a magnetic field (10T) parallel to the long side of the tape 2. The performance was excellent as 1×10”A/d.

In addition, the space factor of the stabilized copper with respect to the total cross-sectional area of the wire was measured.

That is, as a result of dissolving each fraction in HNO and aqueous solution and taking specific gravity into consideration, the results remained within the range of ±2 s with respect to the target of 13-.

(Effects) As detailed above, according to the method of the present invention, the space factor of the stabilized copper has an internal stabilizing metal that can be very close to the target m value, and even though the peeling process is performed, no loss is caused. It has remarkable effects such as producing superconducting wire with good yield.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 3 are cross-sectional views of an in-situ dual compound superconducting wire produced by a conventional method, and FIG. 4 is a cross-sectional view showing an example of the compound superconducting wire of the present invention. DESCRIPTION OF SYMBOLS 1... Stabilizing metal layer, 2... Shielding layer, 3... Stabilizing metal layer, 4... Stabilizing metal plating layer, 5... Soldering layer, 6... Stabilizing metal tape layer. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure 4

Claims (2)

[Claims] (1) In-situ A_3B compound superconducting wire, characterized in that a stabilizing metal is arranged inside and on the outer periphery of the wire. (2) In producing the in-situ A_3B compound superconducting wire, at least one hole is bored inside the in-situ composite material, and a stabilizing metal or a stabilizing metal coated with a diffusion barrier is inserted into the hole. 1 process, a 2nd process of applying metal plating to the surface, a 3rd process of extruding, a 4th process of plating the extruded material with B element after surface reduction processing, and forming an A_3B compound inside the wire, A method for manufacturing a compound superconducting wire, comprising a fifth step of adding a stabilizing metal in contact with the surface.