JPS63276821A - Manufacture of compound superconductive wire - Google Patents

Abstract

PURPOSE:To facilitate the processing of a compound superconductive wire by burying a compound superconductive material into a recessed groove with an opening part formed longitudinally at a peripheral part of a metallic filament and next closing both side edges of the opening part. CONSTITUTION:A part of a metallic filament 1 made of copper or copper alloy is cut out by the use of a cutter so that a recessed groove 2 with an opening 3 is formed. A compound superconductor 5 is buried into the recessed groove 2, and next both side edges 4a, 4b of the opening part are closed in dice processing by a plasma welding method or the like. Accordingly a compound superconductive wire made of an oxide superconductor of a layered perovskite type or the like, high in its critical temperature, can be obtained and so a superconductive magnet can be formed.

Description

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

(Prior Art) In recent years, since it was announced that layered perovskite oxides based on Ba-La-Cu-0 may have a high critical temperature, research on oxide superconductors has been conducted in various places. There is (Z, Phys, B Condensed Ma
tter 64゜189-193 (1986), among which multilayer perovskite type oxide superconductors represented by Y-Ba-Cu-0 type (AB* c s o - type) have a Tc of 90 or more. It is a very promising material because it shows temperatures higher than liquid nitrogen (Phys, Rev, L
stt, vol, 5B No, 9. p90&-910)
.

However, these oxide superconductors have conventionally been produced only in the form of pellets by sintering.

Furthermore, when considering applications such as superconducting magnets, it is necessary to make the superconductor into a wire. Furthermore, since a large current is passed, a conductive material such as Cu is required to prevent damage to the superconducting material even when the superconducting material changes to normal conductivity.

(Problems to be solved by the invention) As described above, oxide superconductors such as layered perovskite type are very promising materials, but because they cannot be processed into wires, it is difficult to apply them to superconducting magnets, etc. be. Therefore, an object of the present invention is to provide a method for manufacturing a superconducting wire using a compound superconductor.

[Structure of the invention]

(Means and effects for solving the problems) In view of the above-mentioned problems, the present invention applies special processing to a strip made of a thick metal such as Cu or a Cu alloy, and has a special process inside the Cu strip. The compound superconductor is embedded using a method, and the specific method will be explained below with illustrations.

FIG. 1 is a sectional view of the metal strip 1. FIG. When the metal strip 1 has a circular cross-sectional shape as shown in the figure, the outer diameter is about 6 mm.

The metal strip 1 may have a thick polyhedral cross section.

In the present invention, first, a special process is applied to the metal strip 1. At this time, one part of the metal strip 1 is cut while cutting a blade (not shown) into the metal strip 1 along the dotted line in FIG. By cutting and raising the part, the shape shown in Fig. 2 is obtained.

In this machining, a concave groove with a width of approximately 2 mm is formed in the metal strip 1 due to the biting of the blade.

By cutting with the knife, the opening 3 of the groove 2 has both side edges 4a and 4b rising up in two shapes, long and short, and the ends of each side edge 4a and 4b have a tapered and sharp shape.

During the above processing, if the opening width of the groove 2 is insufficient, the groove 2 may be recessed or the inner surface of the groove 2 may be removed by cutting, grinding, or the like.

Next, a compound superconductor is embedded in the groove of the metal strip. Any method can be used for this buried interior as long as it can maintain the properties of the compound superconductor, but a dense buried layer can be efficiently formed by using a plasma spraying method.

(Figure 3).

Next, the openings 4a and 4b are closed, but it is effective to use different closing methods depending on whether the openings 4a and 4b are both short due to machining or the like, or when they stand up in two different lengths.

First, when both 4a and 4b are short, the opening 3 is filled with the same material as the metal strip. This can also be said to be a method of coating the superconducting material 5 with metal.

Any method such as mechanical, physical, chemical, etc. can be used. However, in order to achieve smooth and efficient closure, thermal spraying or die processing is preferred.

In the case of the thermal spraying method, it is only necessary to coat the opening 3 with the same metal as the strip by plasma spraying, flame spraying, etc. from above the opening 3. In the case of this thermal spraying method, the opening 3 and both side edges 4a and 4b are coated in the shape. This is preferable because it can be opened regardless of the situation.

Next, a die processing method that is effective when both side edges 4a and 4b have two lengths and a short length will be described.

At the time of this die processing, the long side edge 4a of the opening 3 is cut into the short side edge 4 at the longitudinal end of the metal strip 1 in advance.
b, and pass the metal strip 1 through a die from the tip of the polymerized state.

In this way, the metal strip 1 follows the overlapping state of both side edges 4a, 4b at its tip.
The remaining part of the metal strip 4b is also in a polymerized state, and at this time, the metal strip 1 whose external shape is formed into a circular shape by a die and whose diameter is reduced increases the overlap of the above-mentioned side edges 4a and 4b, and furthermore, the above-mentioned reduction It becomes distracted in the longitudinal direction as the diameter increases.

As a result of the above-mentioned overlapping state, the opposite side edges 4a and 4b of the metal strip 1 are tightly closed to each other, and as a result, the opening 3 of the groove 2
is erased, and the superconducting material 5 in the groove 2 is covered with the metal strip 1 as shown in FIG.

During the die machining described above, it is preferable to reduce the diameter of the metal strip 1 by several die machining steps, rather than reducing the diameter of the metal strip 1 to the final outer diameter in one die machining process. The outer diameter of the metal strip 1 can be adjusted to the final diameter (5 mφ) without increasing the
) can be reduced in diameter.

In addition to the methods described above, groove processing can also be done by die processing, mechanical grinding, etc. In that case, the shape shown in Figure 5 is likely to be obtained.In this case, the plasma spraying method described above is appropriate for closing 4a and 4b. I can say that.

Furthermore, it goes without saying that even if the superconducting wire is heat-treated to improve its superconducting properties, the effects of the present invention will not be impaired.

As the superconductor, an oxide superconductor containing a rare earth element and having a perovskite structure can be used. This material only needs to realize a superconducting state, and ABazC
u307-1 series (A is Y + Yb t Ha, D
y, Er.

Multilayer perovskite type such as Tm, Lu), 5r-La-
The oxide is an oxide having a perovskite structure in a broad sense, such as a layered perovskite type such as Cu-0 type. Rare earth elements are also broadly defined to include Se, Y, and lanthanum. Typical systems include Y-Ba-Cu-0 system, 5c-Ba-Cu-0 system, 5r-La-Cu- system, and Sr and Ba.

Examples include systems with CaFeE exchange. Each raw material is Y2
Oxides such as O, BaO, CuO, A et al. 01 can be used. In addition to these oxides, compounds such as carbonates, nitrates, hydroxides, etc. that are converted into oxides after firing may be used.The elements constituting the perovskite-type oxide superconductor are basically The composition is mixed so that it has a stoichiometric composition, but it does not matter if it deviates slightly due to manufacturing conditions, etc. 6 For example, in the Y-Ba-Cu-0 system, Y
The standard composition is 1 mol and Cu3 mol, but a slight deviation is not a problem in practice.

(Example) Example-1 A Cu wire rod with a diameter of 7 mm and a length of 3 m was processed with a cutter into the cross-sectional shape shown in Figure 5.
-N in Ba-Cu-0 perovus-type superconductor oxide
o-44, particle size powder was plasma sprayed under the conditions of 30V and 750A, and buried inside.The particle size was 10 to 44μs.The superconducting properties were investigated using this compound superconducting wire.
The critical temperature was 30K and the critical current was 5A, showing good characteristics.

Example-2 A Cu wire rod having a diameter of 6 cm and a length of 3 m was processed into the same cross-sectional shape using a cutter.Then, Y-Ba-
Next, die processing was carried out in which powder of Cu-0 perovskite type superconductor oxide was embedded, and the opening 3 shown in FIG. 5 was closed. Furthermore, heat treatment was performed at 850° C. for 96 hours.

When the superconducting properties of this compound superconducting wire were investigated, it showed good properties with a critical temperature of 30 K and a critical current of 5 A.

[Effect of idea]

As explained above, according to the present invention, it is possible to obtain a compound superconducting wire using an oxide superconductor such as a layered perovskite type having a high critical temperature, which greatly contributes to the application to superconducting magnets, etc. be.

[Brief explanation of drawings]

Figure 1 is a sectional view of the Cu strip, Figure 2 is a sectional view of the Cu strip after processing with a knife, Figure 3 is a sectional view of the Cu strip with a superconductor buried inside, and Figure 4 is a cross-sectional view of a Cu strip body covered with a superconductor. FIG. 5 is a cross-sectional view of the Cu strip after die grinding or the like. 1... Cu striations 2... Grooves or sinuses 3...
・Openings 4a, 4b...both side edges 5...
Superconductor agent Patent attorney Nori Chika Yudo Mitsuyuki Matsuyama

Claims (4)

[Claims] (1) After forming a groove or a cavity with an opening in the outer periphery of a metal strip in the longitudinal direction of the strip, a compound superconducting material is buried inside the groove or cavity, and the groove or cavity is filled with a compound superconducting material. A method for producing a compound superconducting wire, the method comprising closing both sides of an opening. (2) The method for producing a compound superconducting wire according to claim 1, wherein the interior embedding of the compound superconducting material is carried out by a plasma spraying method. (3) A method for manufacturing a compound superconducting wire according to claim 1, characterized in that both sides of the opening are closed by thermal spraying of the same material as the strip. (4) The method for manufacturing a compound superconducting wire according to claim 1, wherein the strip is made of copper or a copper alloy.