JPS6388710A - Manufacture of nb3al superconductor - Google Patents

Abstract

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

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a method for manufacturing Nb5AJ2 superconducting wire.

(Prior art) Compound-based superconducting materials generally have superior superconducting properties compared to alloy-based superconducting materials. For example, Nbqkf
l has a higher critical magnetic field (HO2) than Nb3Sn,
It has advantages such as excellent mechanical properties, but Nb)A
In addition to the high temperature at which β is produced, it also has the disadvantage of requiring a long heat treatment.

That is, according to research on the diffusion process of the Nb-AJ2 system, the diffusion rate of Nb-Aβ is extremely slow <,800
In order to obtain Nb5Al with a thickness of several μm at around 0.degree. C., an extremely long diffusion time is required.

However, if the grain size of Nb becomes very small,
Grain boundary diffusion becomes dominant, making it possible to create Nb3Au superconducting materials, and although microscopic samples have been experimentally created using a mixed powder of Nb and A℃, it is difficult to make long, practical materials. It is difficult to obtain wire rods with high quality.

That is, when manufacturing Nb and AJ superconducting wires using powder, it has been reported that the superconducting properties deteriorate as the amount of processing increases, and for this reason, a manufacturing method using the secondary multi method has been attempted. There is. In this method, a plurality of composite rods are processed by filling a Cu tube with a mixed powder of Nb and AJ2, which is then housed in the Cu tube and processed.

However, the above-mentioned secondary multi-method has low workability, and it is difficult to perform a working degree of 10' or more, which is necessary for improving superconducting properties.

(Problems to be solved by the invention) The present invention has been made to solve the above problems.
NbxAfl is produced using a powder method that eliminates the deterioration in workability caused by the secondary mulch method using powder and allows for fine wires with high workability.
The purpose of the present invention is to provide a method for manufacturing a superconducting wire.

[Structure of the Invention] (Means for Solving the Problems) The method for manufacturing a Nb5AJ2 superconducting wire of the present invention includes (a) C
A step of filling a mixed powder of Nb and A°C or a mixed powder containing these as main components into a u or Cu alloy tube, sealing both ends thereof, and then subjecting the tube to hydrostatic extrusion; A process of chemically removing Cu or Cu alloy tubes, and (c) housing these multiple strips in a Nb or Ta tube with a stabilized Cu tube around the outer periphery, and adding Nb to the gap between the tubes.
and i or a mixed powder containing these as main components, sealing both ends of the Cu tube, and then subjecting it to hydrostatic extrusion and wire drawing; (d) Nb, AJ! and a step of applying heat treatment for generation.

(Function) In the method for manufacturing Nb5Ai superconducting wire of the present invention, C
When making secondary mulch from the mixed powder compressed into n or Cu alloy tubes, removing this tube greatly improves workability, making it possible to obtain a workability of 8 x 105 or higher. .

Furthermore, multiple strips of the above mixed powder rods are stabilized on the outer periphery C.
When accommodating u in a Nb or Ta tube without arranging it, filling the gap with Nb, A, f2, or a mixed powder containing these as main components acts as a diffusion barrier.
The space factor inside the Nb or Ta tube is improved, making subsequent hydrostatic extrusion easier. In the case of the conventional secondary mulching method or when the above-mentioned gap is not filled with the mixed powder, the space factor of the mixed powder is wide and hydrostatic extrusion processing is difficult.

(Example) Nb powder with a particle size of 150 μlφ and A (powder with a particle size of 75 μmφ) were blended to have a Nb-&wt% composition of 11, and after thoroughly mixing these powders, they were exposed by hydrostatic pressure treatment. Compression molded to a diameter of 80v1φ.This molded body has an outer diameter of 9G.
The rod is housed in a Cu tube with a diameter of 5 mm and a thickness of 5 mm, and both ends of the rod are sealed with a Cu alloy, and then a rod with an outer diameter of 10 mm is manufactured by hydrostatic extrusion.

Next, the outer Cu tubes of the rods were dissolved and removed using nitric acid to give an outer diameter of 8.9 mm, and the 61 rods were then reduced to an outer diameter of 88 g.
It was housed in a Ta tube with a diameter of 100 mm and a thickness of 3.5 mm, and a Cu tube with an outer diameter of 100 mm and a J7 diameter of 5 rm was placed outside the Ta tube. The gap inside the Ta tube is filled with a mixed powder of Nb and AJ2 (the particle size and composition are the same as those for rod molding), and both ends of this Cu'l' are sealed with a Cu alloy, and hydrostatic extrusion processing is performed for three times. After extrusion and extrusion to an outer diameter of 10 mm, the wire rod was subjected to swaging and wire drawing to produce a wire rod with an outer diameter of 1.08 mm.

The degree of processing of this wire was 8×10', and the superconducting properties after subsequent heat treatment also showed good values.

[Effects of the Invention] As described above, according to the method for manufacturing a NbxAf superconducting wire of the present invention, when performing secondary mulching, multiple strips of a molded body of powder from which the outer layer of Cu or Cu alloy tubes have been melted and removed are formed. By filling the double tube with powder and powder, the workability is significantly improved and it becomes possible to perform a high degree of workability.

Applicant Showa Electric Cable↑Ten Co., Ltd. Representative Patent Attorney Sasa Suyama - (1 other person)

Claims (1)

[Claims] A method for manufacturing a Nb_3Al superconducting wire, characterized by comprising the following steps. (b) Filling a Cu or Cu alloy tube with a mixed powder of Nb and Al or a mixed powder containing these as main components, sealing both ends thereof, and then subjecting the tube to hydrostatic extrusion; (c) A step of chemically removing the outer layer of Cu or Cu alloy tube; and (c) housing these multiple strips in a Nb or Ta tube with a stabilized Cu tube around the outer periphery, and adding Nb and Al to the gap between them. A step of filling the mixed powder or a mixed powder containing these as main components, sealing both ends of the Cu tube, and then subjecting it to hydrostatic extrusion processing and wire drawing; and (d) a step of performing heat treatment to generate Nb_3Al.