JP2621383B2 - Manufacturing method of oxide superconducting coil - Google Patents

Description

The present invention relates to a method for manufacturing a coil using an oxide-based superconductor.

[Related Art] In recent years, the development of oxide superconductors has been advanced at a remarkable speed. These superconductors significantly exceed the maximum critical temperature of conventional compound-based superconductors, 23K of Nb ₃ Ge, and are typically Ba-La-Cu-O, La-Sr-
Cu-O-based, La-Ca-Cu-O-based and Y-Ba-Cu-O-based oxides can be used.

Since the above-mentioned superconductor has a possibility that it can be used from its critical temperature to the temperature of liquid nitrogen or higher, it is expected to bring about industrial innovation.

When a magnet is formed from such a material, the plastic deformability is extremely small and brittle, so a method of winding a coil after processing into a wire such as that used in a conventional alloy superconductor such as a conventional Nb-Ti alloy, or Use a method of forming a superconducting coil by performing heat treatment after wire or coil processing, such as the compound processing method used for compound superconductors such as Nb ₃ Sn, bronze method or jelly roll method. Is not appropriate.

Currently, as a means to overcome the above difficulties,
Attempts have been made to fill the inside of a metal tube with fine powder of oxide superconductor, subject it to rolling and the like, wind it into a coil, and then fire it.

[Problems to be Solved by the Invention] However, in the above-mentioned method, there is a problem that the superconducting property is reduced in each process such as forming into a wire, and the critical temperature is remarkably lowered.

In addition, since the metal pipe is filled with powder and processed to the final shape and then fired, the powder in the metal pipe is not processed uniformly, and shrinkage and non-uniform diffusion bonding, which are unique problems during firing, or metal There is a problem that the characteristics are deteriorated due to a difference in thermal expansion between the tube and the fired body.

Further, it is also difficult to coil the wire manufactured by the above method.

The present invention has been made to solve the above-described difficulties, and does not require a wire forming step, directly forming a coil,
It is an object of the present invention to provide a method of manufacturing an oxide superconducting coil in which a decrease in characteristics due to wire processing and coil processing is prevented.

[Means for Solving the Problems] In order to achieve the above object, a method for manufacturing an oxide superconducting coil according to the present invention comprises: (a) an oxide superconductor or a constituent material which produces an oxide superconductor by firing. (B) a step of firing the cylindrical body; (c) a step of coating the inner and outer sides of the fired cylindrical body with a curable resin; Then, a step of forming a spiral groove in the outer curable resin layer and the fired cylindrical body by machining, and (e) a step of filling the groove with a curable resin. I do.

In the present invention, first, a cylindrical body is formed by firing. This cylindrical body is subjected, for example, to hydrostatic pressure treatment (CIR or HIR) of an oxide superconductor having a particle size of about several μm or a fine powder made of a constituent material that forms an oxide superconductor by firing.
After forming into a cylindrical shape by IR), it can be formed by firing.

An example of the firing conditions in this case is as follows: Y—Ba—Cu—O
In the case of a system oxide, the temperature is 900 to 950 ° C. for 2 to 24 hours.

The curable resin for coating the above-mentioned cylindrical body preferably has a low viscosity. This is to penetrate into a large number of voids inside the fired cylindrical body to compensate for the brittleness peculiar to the oxide. As such a curable resin, for example, a bisphenol A type epoxy resin (50 to 500 cp; ° C).

The groove for forming the coil is formed by machining, for example, cutting. The cutting conditions may be the same as those for ordinary alumina, but in the case of Y-Ba-Cu-O, the cutting is performed without using an oil-based grinding fluid other than water or a machining fluid.

[Operation] In the manufacturing method of the present invention, a coil is formed on a cylindrical fired body by machining, and then the coil is formed without performing a process such as rolling, drawing, or bending to perform an insulating process. It can be formed, thereby preventing the property of the oxide from deteriorating. Further, since the inside and outside of the fired body are covered with the curable resin at the time of machining, the groove can be formed with high accuracy, and the accuracy and characteristics of the coil can be improved.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. In these figures, the same parts are indicated by the same reference numerals.

FIG. 2 shows an apparatus for molding a fine powder into a cylindrical body, wherein 1 is a metal cylinder, 2 is a divided cylinder obtained by dividing a metal cylinder into four, and 3 and 4 are cylindrical cylinders each having a flange portion. Sealing members 5 and 6 are rubber tubes, and 7 is powder. In FIG. 1, a divided cylinder 2 is fitted on the outer side of a metal cylinder 1, and a rubber tube 5 is coated to fix the divided cylinder 2 and to easily separate a molded body. Metal cylinder 1
Is longer than the divided cylinder 2 and is disposed so as to protrude at both ends. The sealing member 3 is fitted into both ends, and the flange portion 3a of the sealing member 3 and the outer rubber tube 6 are airtightly bound by a binding wire 8, and the rubber tubes 5, 6
The powder 7 is filled in between. Further, a sealing member 4 is fitted to the metal cylinder 1 and the sealing member 3 in order to maintain airtightness, and the sealing member 4 and the sealing member 3 are also bound by a binding wire.

After having been configured as described above, the inside of the rubber tube is depressurized using an injection needle, subjected to hydrostatic pressure treatment, and then the metal cylinder, the divided cylinder, the sealing member and the rubber tube are removed,
Produce a molded cylinder.

As the above-mentioned powder, for example, a Y-Ba-Cu-O oxide fine powder having a particle size of about 5 μm, which is produced by compressing a raw material powder, molding and then repeating a firing and crushing process, is used.
Also, if an example of the dimensions of the cylindrical body is shown, the outer diameter is 30 mmφ, the inner diameter is 25 mm.
mmφ, length 100mm, while molding pressure is about 2000kg / cm ²
It is about.

FIG. 3 shows the cylindrical body 10 manufactured as described above. After the cylindrical body 10 is subjected to a heat treatment at 900 to 950 ° C. for 2 to 24 hours and fired, the inside and outside of the fired cylindrical body 10 ′ are coated with epoxy resins 11 and 11 ′ as shown in FIG. Then, as shown in FIG. 1, a spiral groove is formed on the outer epoxy resin layer 11 and the cylindrical body 10 'by cutting.
After the formation of 12, the groove is filled with an epoxy resin 13 and hardened to produce the coil 14.

[Effects of the Invention] As described above, according to the method for manufacturing an oxide-based superconducting coil of the present invention, it is possible to directly form a coil without the need for coiling by plastic working such as rolling or drawing or bending. Therefore, the production is easy and the deterioration of the characteristics of the superconductor can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partial cross-sectional view showing one embodiment of an oxide superconducting coil manufactured according to the present invention, and FIG. 2 (a) shows a molded article used in FIG. FIG. 3 (b) is a cross-sectional view taken along line AA 'of FIG. 3, FIG. 3 is a partial cross-sectional view of a molded body used in FIG. 1, and FIG. FIG. 4 is a partial cross-sectional view showing the state of FIG. 10, 10 ': Cylindrical body 11, 11', 13: Epoxy resin 12: Spiral groove 14: Coil

Claims (1)

(57) [Claims] (1) a step of molding a fine powder of an oxide superconductor or a constituent material which forms an oxide superconductor by firing into a cylindrical body; (b) a step of firing the cylindrical body; C) a step of coating the inside and outside of the fired cylinder with a curable resin; and (d) forming spiral grooves in the outside curable resin layer and the fired cylinder by machining. And (e) a step of filling the groove with a curable resin.