JPS63133406A - Compound superconductor - Google Patents

Abstract

PURPOSE:To enable mass-production industrially by refraining from applying heat treatment affecting superconductivity of compound superconductive material filled at time of filling process during or after cross-section reduction processing. CONSTITUTION:The process consists of a filling process to fill pulverulent or fibrous compound superconductive material 3 displaying superconductivity into a metallic cylinder 2 and a cross-section reduction process to obtain a prescribed shaped compound superconductor by cross-section redution processing of the metallic cylinder 2 after the filling process. During the cross-section reduction process and after said process heat treatment affecting the superconductivity of the compound superconductive material 3 shall not be applied. Since heat treatment is not required it is suitable for industrial mass-production.

Description

[Detailed description of the invention] The present invention relates to compound superconductors such as compound superconducting wires.

Superconducting equipment includes energy-related equipment such as nuclear fusion reactors, superconducting generators, and power storage, as well as high-energy physical equipment such as accelerators, transportation equipment such as magnetic levitation trains and ship propulsion, and medical equipment such as pion therapy devices. The use of superconducting wires is gradually being realized in a wide range of fields, and as these devices progress and become larger, there is a need for superconducting wires that can withstand high magnetic fields and high-speed excitation.

For example, in high magnetic fields of 8TC Tesla or higher, compound superconducting wires such as Nb5Sn and VsGa, which have excellent high-field characteristics, are usually used, but since these types of superconducting wires are made of compounds, they are not mechanically fragile. For this reason, various improvements have been made in structure and manufacturing. Specifically, one possible example is a discontinuous fiber type compound superconducting wire, in which current is maintained due to the proximity effect of the amount of discontinuous fiber superconducting material, so even if a large electromagnetic force acts and deforms, the superconducting material They have the advantage of retaining their superconducting current characteristics as long as their mutual spacing is less than a certain distance.

Such superconducting wires include, for example, C containing teeth and Sn'' components.
The U-based alloy is rapidly cooled and solidified from a molten state to finely disperse Nb particles in a Cu-5n bronze matrix, and this matrix is subjected to drawing processing etc. to form the particles into discontinuous fibers, followed by heat treatment. By applying
A method of producing Nb, 3n on the surface portion of discontinuous fibers, or a method of processing and sintering or hot extruding Nb powder and Cu and Sn or Cu-Sn alloy powder, followed by wire drawing. , 9Cu and Sn or a Cu-Sn alloy, Nb discontinuous fibers are formed, and then heat treatment is performed to generate Nb and Sn on the surface of the Nb discontinuous fibers.

However, in the method of rapidly solidifying Cu-based alloys, it is necessary to set the cooling rate as far as possible in order to disperse Nb finely and homogeneously. This made it difficult to manufacture on an industrial scale. In addition, the method using powdered teeth, etc.
Since b is a chemically active metal, its surface is easily oxidized and adsorbs gases such as N7 and N1, significantly impairing workability in subsequent processes. For this reason, such methods require special pretreatment and handling considerations to prevent oxidation and contamination with the above gases, and it is difficult to produce this type of reliable wire material industrially. It was very difficult to obtain.

The present invention has been made in view of the above-mentioned points, and the superconducting properties hardly deteriorate even when deformed due to mechanical stress caused by electromagnetic force, and it is possible to mass-produce it industrially. The purpose of the present invention is to provide a compound superconductor having a possible structure.

That is, the present invention is made by directly surrounding and disposing metals with high mechanical strength and metals with relatively low mechanical strength and easy to process, such as Ag, At, and Cu, in this order around the circumferential surface of a compound superconducting material. It is a compound superconductor characterized by the following.

In the present invention, the compound superconducting material is Nbs
Sn, Nbs Ge, 'Nbs AL+ Vs
A1 such as Ge, Va Ga, Vs Si, etc.
Type 5 compound, HfVt type C15 compound.

NaC2 type compounds such as NbC and NbN t' B aP
b I -X B l z O3.

Oxides such as Li++zTi2-XO4, PbMoa
It contains Chebrel phase compounds such as Ss, etc., and these substances are used in the form of powder or fibers with a particle size or diameter of several μm to several tens of Xs degrees.

In addition, the above-mentioned metal with high mechanical strength refers to 10 to 10% of Ni.
30% cupronickel and Cu containing 1%
Cu-Ni such as Monel containing 0-40 wt.
Alloys include precipitation hardening copper alloys such as u-13e and Cu-Ti, non-magnetic stainless steels such as SUS 304 and 5US316, and metals with excellent cold workability such as Ta and Ta.

Next, the present invention will be explained based on an example of a discontinuous fiber type P1Sn compound wire. That is, Nb*Sn fibrous powder with a wire diameter of 500 to 3200 z and a length of 0.5 to 5 μm was mixed with Cu-30 weight/4'- with an outer diameter of 11 m5 and an inner diameter of Low.
Fill the Cent Ni pipe (cupronickel pipe) with an outer diameter of 3.2 + a and an inner diameter of 11.8 on the circumferential surface of this pipe.
A wire rod with an outer diameter of 3+m is created by coating the copper pipe of ■ and drawing these composite metals integrally by cold wire drawing, and then this wire rod with a distance across flats of 2.8 After forming the wire into a hexagonal cross section, 127 wires are inserted into a copper container 1 having an outer diameter of 50III+ and an inner diameter of 37.5cm, as shown in FIG.
1' is the copper coated on the nozzle, 3 is Nb*
It is Sn fibrous powder. ), hot extrusion processing was performed at 650℃ to create a wire rod with an outer diameter of 20 wl1, and finally, this wire rod was subjected to cold wire drawing processing again to create a round wire with a diameter of 0.5 mm. A discontinuous fiber type Nb, Sn compound wire according to the present invention was obtained by twisting the wire to a length of 20 cm.

The obtained discontinuous fiber type Nb, Sn compound wire was heated in liquid helium at a temperature of 4.2
The critical current density in the Nb3Sn compound in the cupronickel mother plate was measured by applying a Tesla bias magnetic field and applying bending strain, and the results are shown as curve A in FIG.

For comparison, the critical current densities of a commercially available continuous fiber ultrafine multicore wire and a discontinuous fiber type NBS Sn wire obtained by a conventional method were measured under the same conditions as described above, and the results are shown in Figure 2. They are shown as curves B and C.

As is clear from FIG. 2, the critical current density of the discontinuous fiber Nb s S n compound wire according to the present invention at a strain of O is several times higher than that of commercially available and conventional wires. There is. This is because the wire of the present invention does not contain a non-superconducting material such as Cu-8n bronze in the cupronickel unlike conventional wires, but is entirely composed of Nb3Sn superconducting material.

In addition, the critical current density of the wire of the present invention hardly decreases even when the strain is 5%, whereas the wire obtained by the conventional method has a strain of 1%.
%, the critical current density decreases.

This is because the wire of the present invention is composed of fine Nb and Sn fibrous powder. As described above, the discontinuous fiber type NbsSn compound wire according to the present invention has extremely excellent superconducting properties, and even when mechanical stress is applied, the superconducting properties hardly deteriorate.

In addition, in the above example, cupronickel/Tai Eve 2
The coated copper pipe 1' is provided to quickly transmit the heat generated by the fluff jacket or the like in the outer radial direction, and therefore does not necessarily need to be provided.

As explained above, according to the present invention, a compound superconductor is formed on the peripheral surface of a compound superconducting material using metals with high mechanical strength and metals with relatively low mechanical strength such as At, Ag, and Cu that are easy to process. Since the structure is such that Cu-5 is directly surrounded in this order, unlike conventional superconductors of this type,
It is industrially valuable because it does not contain non-superconducting substances such as n-bronze, the current density per unit cross-sectional area increases dramatically, and the structure is simple. In an electromagnet or the like made by winding the compound superconducting wire according to the present invention, even if a large electromagnetic force acts on the wire and deforms it, the powdery compound superconducting material moves by the wave and the proximity effect is maintained. Therefore, it is possible to effectively prevent a decrease in current density, and since a metal with high resistivity such as cupronickel is used as a metal with large mechanical strength, dynamically changing current such as Noculus magnet is used. It can significantly reduce alternating current loss due to magnetic fields, and therefore can be widely used as a high-performance and reliable wire in high-field electromagnets where large electromagnetic forces act, and its practical value is great.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a billet constructed by arranging a plurality of composite metal wires in a copper container in an embodiment of the present invention, and FIG. FIG. 2 is a characteristic diagram showing changes in critical current density when strain is applied to a composite multicore compound superconducting wire and a discontinuous fiber type Nb, Sn compound wire obtained by a conventional method. 1...Copper container, 2...Cuzoronickel pipe, 3
...Powdered Nb5Sn compound superconducting material.

Claims (12)

[Claims] (1) Metals with high mechanical strength and metals with relatively low mechanical strength and easy to process, such as Ag, Al, and Cu, are directly surrounding the compound superconducting material in this order. Compound superconductor. (2) The compound superconductor according to claim 1, wherein the compound superconductor is in powder form. (3) The compound superconductor according to claim 1, wherein the compound superconductor is in the form of discontinuous fibers. (4) The above compound superconducting materials are Nb_3Sn, Nb_3
Ge, Nb_3Al, V_3Ge, V_3Ga, V_3
The compound superconductor according to any one of claims 1 to 3, which is an A15 type compound such as Si. (5) The above compound superconducting material is C15 such as HfV_2
The compound superconductor according to any one of claims 1 to 3, which is a type compound. (6) The above compound superconducting material is NbC, NbN, etc.
The compound superconductor according to any one of claims 1 to 3, which is an aCl type compound. (7) The above compound superconducting material is BaPb_1_-_xB
The compound superconductor according to any one of claims 1 to 3, which is an oxide such as i_xO_3, LiH_xTi_2_-_xO_4. (8) The compound superconductor according to any one of claims 1 to 3, wherein the compound superconductor is a Chebrel phase compound such as PbMo_6S_8. (9) The compound superconductor according to claim 1, wherein the metal with high mechanical strength is a Cu-Ni alloy represented by cupronickel, monel, etc. (10) The metals with high mechanical strength are Cu-Be, C
The compound superconductor according to claim 1, which is a precipitation hardening copper alloy represented by u-Ti. (11) The above metal with high mechanical strength is SUS_3_0
Claim 1, characterized in that it is a non-magnetic stainless steel alloy represented by _4, SUS_3_1_6, etc.
Compound superconductor described in Section. (12) Claim 1, wherein the metal with high mechanical strength is a Nb-based or Ta-based metal.
Compound superconductor described in Section.