JPS6049512A - Stabilized superconductive conductor - Google Patents

Abstract

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

Description

TECHNICAL FIELD The present invention relates to stabilized superconducting conductors, and more particularly to improvements in those having a diffusion barrier layer between a bronze matrix and a stabilizing metal.

[Prior art]

Stabilized superconducting conductor number, Nb in bronze matrix
A3B type compound superconductor such as 8Sns Va Ga is distributed, and a stabilizing metal such as copper is integrally provided on the outer periphery (or in the center) of the bronze matrix.

In such a stabilized superconducting conductor, element 13 (5n1G in the case of Sn bronze) in the bronze matrix
a) In the case of bronze, when Ga) diffuses into the stabilizing metal, 1. The purity of the stabilizing metal decreases, the conductivity decreases,
There is a possibility that the function as a stabilizing metal may be impaired. Conventionally, therefore, a barrier layer of a shielding metal such as niobium, vanadium, tantalum, etc. is provided between the bronze matrix and the stabilizing metal to prevent the original iB in the bronze matrix from diffusing into the stabilizing metal. It has been proposed (U.S. Pat. No. 4,205,119, etc.)
. A stabilized superconducting conductor having such a barrier layer is generally prepared by wrapping a piece of shielding metal tape around the bronze matrix with a width sufficiently longer than the circumference of the bronze matrix so that both sides overlap, or Or do you wind it many times, coat the outer circumference with a stabilizing metal to create a base material, and then process it to reduce its cross section and heat treat it? In addition, there is something that can be obtained.

However, since the shielding metal is a material with poor workability, it is difficult to process the bronze material in the form of a complete 72 cylinder closed in the circumferential direction as described above when it is sandwiched between IJ Lux stabilizing metals and subjected to cross-section reduction processing. There is a problem that it gets damaged due to cracks etc. If the shielding metal is damaged, diffusion will proceed through the damaged area, and its effectiveness as a barrier layer will be greatly diminished.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, an object of the present invention is to provide a stabilized superconducting conductor in which the shielding metal constituting the barrier layer is not damaged by cross-sectional reduction processing.

[Structure of the invention]

In order to achieve the above object, the present invention provides a barrier layer between the bronze matrix and the stabilizing metal such that a plurality of shielding metal strips having a width shorter than the circumference of the bronze matrix overlap each other and cover the entire circumference twice. It is characterized by having a metal strip interposed in the overlap 111S, which has a low work hardening rate and does not diffuse and reduce the conductivity of the stabilizing metal.

〔Example〕

FIG. 1C shows a stabilized superconducting conductor 2 according to an embodiment of the present invention. In the figure, 1 is a bronze matrix, 3 is a filament-like ASB type compound superconductor distributed therein, 5 is a stabilizing metal made of copper, etc., and 7 is between the bronze matrix l and the stabilizing metal 5. It is a barrier layer. This barrier layer 7 has a length shorter than its circumference, ψ
A plurality of shielding metal strips 9 made of 1t1 of niobium, vanadium, tantalum, etc. are used, and they are combined so as to overlap each other so as to cover the entire circumference, and a metal strip 11 with a small work hardening rate is interposed in the overlapped portion. There is one. Since the metal strip 11 with a small work hardening rate comes into contact with the stable dead metal M5, it is made of a material such as copper that does not diffuse and reduce the purity of the stabilized metal and reduce the conductivity.

These metal strips9. The IJ can be provided by spiral winding or vertical alignment on the bronze matrix 1.

When the barrier layer 7 is configured as described above, each of the shielding metal strips 9 has open edges 7' on both sides, so that less force is applied during the cross-section reduction process, and breakage can be prevented. Also, during the cross-section reduction processing of the shielding metal strip No. 9, we press the metal strip 11 which has a small work hardening rate, that is, it is soft.
n % Since it is processed integrally with the other parts, there is less chance of it being overworked and damage can be prevented.

Moreover, since the shielding metal strips 9 overlap each other and cover the entire circumference, the shielding metal strips 9 have a sufficient diffusion prevention effect.

FIG. 2 shows another embodiment of the invention. The barrier layer 7 in this stabilized superconducting conductor consists of a plurality of shielding metal strips 9A spirally wound or longitudinally arranged at intervals around the outer periphery of the bronze matrix 1, and metal strips 11 with a small work hardening rate all over the outer periphery. A plurality of shielding metal strips 9Bf are wound around the circumference, and a plurality of shielding metal strips 9Bf are spirally wound or vertically laid around the outer periphery so as to close the above-mentioned interval.

FIG. 3G shows still another embodiment of the present invention. For barrier layer No. 7 in this stabilized superconducting conductor, a single shielding metal strip 9A having a width slightly shorter than the circumference is placed vertically on the outer periphery of the bronze matrix 1 with a gap between its both side edges.
In addition, JIiJ K) Wrap the JIJ hard work rate reduction metal strip 11 all around the circumference, and wrap another shielding metal strip 9B around its outer periphery so that the gap between its both edges is on the opposite side to the above. It is constructed by vertically aligning.

In addition, in the case of the embodiments shown in FIGS. 2 and 3, layers of shielding metal strips and layers of metal strips with a small work hardening rate may be alternately repeated to form multiple layers as necessary. Can be done.

In the above embodiment, the case where there is one matrix in one stabilizing metal has been explained, but the present invention is equally applicable to the case where there are a plurality of matrix segments in one whole stabilizing metal. t' can be done.

Further, in the above embodiment, the case where the matrix is on the inside and the stabilizing metal is on the outside has been described, but the present invention can be similarly applied to a case where the stabilizing metal is on the inside and the matrix is on the outside.

〔Effect of the invention〕

As explained above, according to the present invention, the barrier layer is formed by overlapping and combining a plurality of shielding metal strips having a width shorter than the circumference thereof, and interposing 191 metal strips with a small work hardening rate in the overlapped portion. Because of this structure, less stress is applied to the shielding metal strip during the cross-section reduction process, which has the practical benefit of preventing damage to the shielding metal strip.

[Brief explanation of drawings]

FIGS. 1 to 3 are respectively R-plane views showing stabilized superconducting conductors according to embodiments of the present invention. 1... Bronze matrix, 3...
As B-type compound superconductor, 5... Stabilizing metal, 7... Barrier layer, 9.9A, 9B° pattern...
Shielding metal strip, 11...Metal strip with low work hardening rate.

Claims (1)

[Claims] (1) Between the bronze matrix in which A and B type compound superconductors are distributed and the stabilizing metal, a shield 11j is placed between the bronze matrix and the stabilizing metal to prevent element B in the IJ lux from diffusing into the stabilizing metal. In a stabilized superconducting conductor provided with a barrier layer made of metal, the barrier layer is formed by combining a plurality of shielding metal strips each having a width shorter than the circumference so as to overlap each other so as to cover the entire circumference. 1. A stabilized superconducting conductor comprising a metal strip interposed therein which has a low work hardening rate and does not diffuse and reduce the conductivity of the stabilized metal.