JPH0378914A - Manufacture of superconductor - Google Patents

Abstract

PURPOSE:To obtain a sufficient doping effect by placing a small block made of an auxiliary component of a superconductor inside a superconductor block and further inside a block made of a third material, and applying machining and thermal treatment thereon. CONSTITUTION:Small hollows 2a, 2b, 2c for containing a predetermined amount of a doping component therein are formed over the whole length of a columnar Nb block 1. The small hollows 2a, 2b, 2c are filled with lines, rods, tubes or plates made of the doping component such as Ti and Ta, thereby forming a compound block. A small space for containing the compound block therein is formed inside a Cu-Sn alloy block, and the compound block is housed therein to form a second compound block. A thermal treatment is applied at 600-800 deg.C onto the second compound block having a desired finish dimension so that a fine wire on Nb3Sn produced with the reaction of Nb and Sn. Doping can be therefore performed suitably and industrially so that a doping effect can be exhibited to the maximum.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing alloy-based and compound-based superconductors that improve superconducting properties.

[Conventional technology]

NbTi is a superconducting wire used in superconducting equipment.
Although Nb5Sn and Nb5Sn wires are used industrially, it is expected that superconducting wires with higher J in higher magnetic fields will be used to miniaturize and improve the performance of devices such as magnets. ing.

For example, in order to improve the Jc characteristics of Nb3Sn,
It is effective to dope Ta, Ti, Hf, etc. 0 Usually, Nb or Cu-3n alloy is alloyed with the above metals to form a composite billet, and this billet is subjected to processing such as extrusion, rolling, wire drawing, etc. Normally, the composite billet is reassembled using wire rods and the same processing steps are repeated.
This process is repeated 2 to 3 times, and heat treatment is performed to synthesize Nb3Sn by a diffusion reaction at the final size. Of course, heat treatment is also performed in hot working, intermediate annealing, etc.

[Problem to be solved by the invention]

However, in the above manufacturing process, there is a problem in that it is not easy to alloy the doping components in Nb. For example, components such as Ti easily evaporate during electron beam melting, making uniform alloying difficult. . On the other hand, there are examples of doping into the Cu-5n alloy, but not only is the amount of solid solution considerably limited, but Cu remains even after the diffusion reaction.
There is a problem that the doping tends to remain in the interior of the dopant, making it impossible to obtain a sufficient doping effect. Furthermore, the conventional method requires a special alloying furnace, which poses a problem in that it requires a great deal of cost and time in industrial production.

[Means and actions to solve the problem]

The present invention provides a method for manufacturing a superconductor that solves the above-mentioned problems, and in which a composite block is formed by arranging small blocks made of subcomponents of the superconductor on a block made of a superconductor or its main component. Alternatively, this composite block is further arranged in a block made of a third material, and then processed and heat treated.

According to the present invention, the N b s S n B144 body is
For example, it is manufactured by the following steps.

That is, as shown in FIGS. 1(a), (b), and (C), small spaces (2a), (2b), and (2C)
is formed over the entire length. (2a), (2b) of the small space part
) and (2C) are as illustrated in FIGS. 1(a), (b), and (C), and a uniform and symmetrical distribution is desirable.

These small spaces (2a), (2b), and (2C) are filled with doping components such as wires, rods, tubes, or plates of Ti or Ta to form a composite block.
A small space for storing the composite block is formed in the Sn alloy block, and the composite block is placed in the small space to form a second composite block. Usually, the second composite block is processed after being included in Cu, etc., and the above operations are repeated as necessary to achieve the desired finished size of 600 to 800 mm.
°C heat treatment is applied, and the reaction between Nb and Sn causes Nb,
A thin line of Sn is generated.

The diameter of Nb wire in finished dimensions is usually 0.1 to 100μ
, especially within the range of 0.5 to 10 Ina, and the reaction proceeds at a practical speed.

On the other hand, in the case of ternary alloys such as Nb-Ti-Zr or Nb-TiTa, the ternary alloy is processed by combining Zr or Ta into a Nb-Ti block and homogenized through processing and heat treatment. Obtainable.

〔Example〕

Examples of the present invention will be described in detail below.

A Nb5Sn superconducting wire with a diameter of 0.5 mm was manufactured by the following process. That is, first, in a Nb billet cross section of 100 mm diameter, there are 9 through holes of 4.3 mm diameter, one in the center and 8 holes equally spaced around the center, and 4.1 mm diameter holes are formed in these through holes. A Ta rod was inserted and processed to a diameter of 4.1 mm. For processing, a Nb billet was coated with Cu using a conventional method, and 8
After hot extrusion at 00°C, rolling and drawing were performed, and then the Cu was removed by etching with HNO to form a Nb composite rod.
Nine through holes with a diameter of 4.3 mm were formed in the cross section of the Sn billet in the same arrangement as in the case of the Nb billet, and the Nb
A composite rod was inserted. This billet has an outer diameter of 150 mbφ
It was put into a Cu tube and sealed, hot extruded at 500"C, rolled and wire-drawn using the usual method to make a 5Iφ wire. Next, this 5Iφ wire was made into a 5Iφ wire with an inner diameter of 50m5φ and an outer diameter of ? It was filled into a 5 mφ Cu tube, processed in the same way, drawn to 0.5 mφ, and subjected to diffusion heat treatment at 680°C for 2.5 days.The Nb3Sn superconducting wire thus obtained was When Jc was measured under a magnetic field of .2 K and IT, a value of 260 A/- was obtained.Also, in the above example, a similar process was performed using a Nb-15% Ti rod instead of the Ta rod. When J was measured for the Nb, Sn superconducting wire that had been subjected to The JcO value remained at 190A/-.

Although the above embodiment described the Nb1Sn superconducting wire, the present invention is not limited to the above embodiment;
It can also be applied to other superconducting materials such as Zr.

〔Effect of the invention〕

As explained above, according to the present invention, after a composite block is formed by arranging small blocks composed of subcomponents of a superconductor on a block composed of a superconductor or its main component, or after the composite block is further processed. Since processing and heat treatment are performed after the material is placed in a block made of the material No. 3, doping can be carried out appropriately and industrially, so that the doping effect can be maximized. Further, the present invention has the advantageous effect that a composite billet of any shape can be easily formed from a block by machining, and no special equipment costs are required.

[Brief explanation of drawings]

FIGS. 1(a), (b), and (C) are explanatory diagrams of a composite billet according to the present invention. 1...Cylindrical block, 2a, 2b, 2c...
・Small space.

Claims (1)

[Claims] After forming a composite block by arranging small blocks composed of sub-components of the superconductor on a block composed of a superconductor or its main component, or after forming a composite block by arranging a block composed of a superconductor or its main component,
A method for manufacturing a superconductor, which comprises placing it in a block made of a substance, and then subjecting it to processing and heat treatment.