JPS5938683B2 - Method for manufacturing compound superconductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a compound superconductor that enables easy production of a stable compound superconductor.

Niobium tritin (Nb3Sn), vanadium trigallium (
Compound superconducting wires such as V3Ga) and niobium trialuminum (Nb3Aι) have higher critical temperatures and higher critical current densities than other alloy-based superconducting wires, and exhibit superior magnetic properties.

However, it has the disadvantage that it is mechanically weaker than alloy-based superconducting wire. Therefore, a conductive layer made of copper or the like that exhibits mechanical strength and stability is usually provided along with the compound superconducting layer, and both layers constitute an electric wire. By the way, conventionally known methods for manufacturing compound superconducting wires equipped with conductive layers that exhibit mechanical strength and stability include methods that apply solid-state diffusion methods and composite processing methods. .

Figure 1a shows a compound superconducting wire manufactured by applying the solid-state diffusion method. In this method, for example, a niobium tape 1 is passed through molten tin, both sides are plated with tin, and a thermal diffusion treatment is performed in this state. A niobium tritin layer 2 is formed on both sides of the niobium tape 1, and a copper tape 4 as a stabilizing material is fixed to the outer surface of the niobium tritin layer 2 via a solder layer 3. A stainless steel tape 5 is attached to provide mechanical strength. In addition, FIGS. 1b and 1c show the case of manufacturing by a composite processing method, and the one shown in FIG. A plurality of wire rods VO are provided, and these are further wrapped in a sheath material 9 made of copper or the like to be integrated, and this integrated wire rod VO is cold drawn and intermediate annealed several dozen times to form a fine wire. After that, a heat diffusion treatment is performed at 700 to 800° C. for several tens of hours to finish. On the other hand, in the case shown in c, a copper gallium alloy wire 11 is drilled, a vanadium material 12 is embedded in the hole, and these are further wrapped with a sheath material 13 to be integrated.
4 is processed and finished in the same way as b. However, the conventional manufacturing method as described above has the following problems.

That is, in the case of the manufacturing method applying the solid state diffusion method shown in Figure 1a, in the final stage a copper tape 4 is soldered for stabilization, and then a stainless steel tape is soldered for strength. 5 is required. For this reason, there is a drawback that manufacturing requires a long time. Also, Figure 1B,
Even when the composite processing method shown in c is adopted, it is ideal that the concentrations of tin and gallium in the copper-tin alloy wire 6 and the copper-gallium alloy wire 11 are high; Due to the increased processing hardness, intermediate annealing was required during wire thinning work, which had the disadvantage of requiring a long time to manufacture. The present invention was made in view of these circumstances, and its purpose is to create a compound that can greatly simplify and facilitate the manufacturing process, and in which the obtained superconductor can also exhibit stable functions. An object of the present invention is to provide a method for manufacturing a superconductor.

Hereinafter, one embodiment of the method of the present invention will be described with reference to the drawings.

Note that this example shows an example of manufacturing a niobium tritin superconducting wire. First, as shown in FIG. 2, a niobium powder 21 and a copper powder 22 are prepared, and the two powders 21 and 22 are mixed in a 1:1 ratio to form a mixed powder 23. Next, the mixed powdered material 23 is introduced into a sintering device 24 and sintered in an argon atmosphere at 1000° C. to be integrated. Next, the integrated product formed by the above sintering is passed through molten tin 25 to dip it in tin, and then cold rolled in a rolling mill 26 to form a thin wire. Next, the thin wires are processed into heat treatment equipment 2.
7 and subjected to thermal diffusion treatment at a temperature of approximately 750 to 800° C. to form a niobium tritin phase between the niobium, copper, and the doped tin, thereby completing the fabrication. As shown in Fig. 3, the superconductor manufactured in this way has a niobium tritin compound 32 extending in the axial direction in the form of fibers in a copper-tin alloy 31, and residual niobium 33 existing around it. It has become a thing. Adopting such a manufacturing method has the following advantages. In other words, the copper in the manufactured superconducting wire exerts a stabilizing effect and an increasing effect on mechanical strength, but since the manufacturing process is based on this copper, reinforcing materials and other materials are added after manufacturing. There is no need for work such as soldering the stabilizing member, and there is also no need for drilling work or covering work, so that the number of manufacturing steps can be reduced. Moreover, even if the powdered copper 22 is sintered together with the powdered niobium 21, a solid solution is not formed, and the copper powder 22 merely functions as a binder. Therefore, compared to, for example, sintering only niobium powder, the sintering temperature can be lowered, and since it is not alloyed, there is no need for annealing when rolling it in the rolling mill 26. Manufacturing time can be significantly reduced. Furthermore, if copper is used as a base and tin is finally dipped into it as in the example, and this dipped material is subjected to heat diffusion treatment, tin will diffuse through the copper at a very fast rate. can lower the activation energy for compound formation,
The temperature during thermal diffusion treatment can be lowered, and the treatment time can be shortened. In addition, the superconducting wire manufactured by this method is niobium 3 as shown in Figure 3.
Since the tin compound phase is formed in the form of fibers in one direction, the processing steps can be greatly simplified when forming ultrafine wires. Although the above-mentioned example is an example of manufacturing a niobium-tritin superconducting wire, a vanadium-tri-gallium superconducting wire can be manufactured by replacing niobium with vanadium and tin with gallium, and similarly. Other superconducting wires can also be produced.

Furthermore, the raw materials forming the powdered copper product and the mixed powdered product cannot be easily specified if it is only one of them. Furthermore, a dipping operation may be performed after the rolling operation. Furthermore, the rolling extrusion method is best cold rolling or cold extrusion, but hot rolling or hot extrusion may also be used. As described in detail above, according to the present invention, it is possible to provide a method for producing a compound superconductor that can produce a compound superconductor that can exhibit stable performance through extremely simple steps.

[Brief explanation of drawings]

Figures 1A, b, and c are diagrams for explaining the conventional manufacturing method of this type of superconductor, respectively. Figure 2 is a diagram for explaining an embodiment of the method of the present invention. Figure 3 is a diagram for explaining the method of the present invention. FIG. 2 is an internal organizational diagram of a compound superconductor produced by the method. 21... Niobium powder, 22...
...Powdered copper, 23...Mixed powdered product, 2
4... Sintering device, 25... Molten tin,
26...Rolling mill, 27...Heat treatment equipment.

Claims (1)

[Claims] 1 A step of pulverizing at least one material among the raw materials forming the compound superconductor and mixing powdered copper thereto, a step of sintering the mixture to form an integrated member, and the above-mentioned integration. A step of dipping another material into the component and then rolling or extruding it, or a step of rolling or extruding the above-mentioned integrated component and then dipping another material into it, and a step of heat diffusion to the component that has gone through this step. 1. A method for producing a compound superconductor, comprising a step of performing a treatment.