JP3033624B2 - Ceramic superconducting conductor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic superconducting conductor applicable to high-voltage power transport such as a power cable and the like, and in particular, has a simple conductor structure and has little deterioration in superconducting characteristics even with bending strain. The present invention relates to a high Ic ceramic superconducting conductor.

[0002]

2. Description of the Related Art Ceramic superconductors having a Tc exceeding liquid nitrogen temperature, such as Y-based, Bi-based, and Tl-based, are known. It has been studied to form such ceramic superconductors into various shapes for use in various fields. For example, when molding into a wire, a metal sheath method is generally used. This is to fill a metal pipe with a ceramic raw material that can become a superconductor to form a composite billet, reduce the cross section and finish it into a composite wire with the desired shape and dimensions, and then heat treat it with a ceramic superconductor. Is what you do.

[0003] The shape of the wire obtained by this method is as follows.
For example, there are round, elliptical, square, and tape-shaped cross sections. In addition, various trial productions of a multi-core wire obtained by bundling a plurality of these wires and a multilayer wire having a structure in which a ceramic superconductor layer is arranged in a concentric cylindrical or spiral shape in a metal layer have been studied.

[0004] In this case, as the material of the metal used, a material having excellent heat conductivity and electric conductivity, for example, Ag, Ag alloy, Cu, Cu alloy, etc. is suitable, but in terms of oxygen permeability and oxidation resistance. In many cases, Ag or an Ag alloy is used. Further, as the cross-section reduction processing method, a conventional plastic processing method such as extrusion, rolling, drawing, or swaging according to the shape of the obtained wire is applied as it is.

In recent years, a ceramic superconducting conductor in which a tape-like composite obtained as described above is vertically wrapped around the outer periphery of a core material such as a metal pipe, a round bar or the like or spirally wound is used as a power cable or the like. It has been studied to apply it to a conductor for power transport such as described above. Specifically, as shown in FIG. 4A, a wide tape-shaped composite D is
One layer per layer is wrapped and wrapped so as to form one layer at a time, and this is laminated in a multilayer shape, or as shown in FIG.
There are those laminated in multiple layers.

In the ceramic superconducting conductor shown in FIG. 4, the width of the tape-shaped composite D wound around the core material A is wide and the cross-sectional area of the ceramic superconductor C inside is increased, so that Ic can be improved. There are advantages such as easy conductor configuration.

[0007]

When the ceramic superconducting conductor shown in FIG. 4 is actually used as a cable for transporting electric power, it is necessary to wind the ceramic superconducting conductor around a drum from the viewpoint of workability in manufacturing, transporting and laying. is there. For this reason, in consideration of winding around a drum, bending due to unwinding, bending during construction work, and the like, it is desirable that the superconducting characteristics do not deteriorate even if the ceramic superconducting conductor is repeatedly bent several times.

However, in the ceramic superconducting conductor shown in FIG. 4, since the width of the tape-shaped composite D is large, Ic is high, but it is weak to the distortion due to repeated bending. Therefore, when bending distortion is applied to the whole, the ceramic superconductor C May be locally deformed or broken, resulting in a problem that Ic is reduced.

It is an object of the present invention to provide a high Ic ceramic superconducting conductor which has a simple structure and whose superconducting characteristics are hardly deteriorated even when repeatedly bent.

[0010]

The ceramic superconducting conductor of the present invention is obtained by conducting various experiments and examinations to improve the above-mentioned disadvantages, and is a tape obtained by providing a ceramic superconducting layer 2 in a metal layer 1. Slits 4 long in the width direction are provided at predetermined intervals in the longitudinal direction of the tape-shaped composite 3 at both ends in the width direction of the tape-shaped composite 3, and the tape-shaped composite 3 is made of a core material such as a metal pipe or a rod. 5 and a desired number of layers and a desired number of layers are vertically wrapped and arranged.

The core material 5 may be a metal pipe, for example, a metal round bar, or a metal pipe obtained by corrugating the metal pipe to have flexibility. Further, there is no restriction on the number of tape-shaped composites 3 vertically wrapped around the outer periphery of the concentric material 5 per layer and the number of layers to be laminated, and as shown in FIG.
The number of sheets may be one per layer, two per layer as shown in FIG. 3B, or more.

There is no particular limitation on the angle of the slits 4 provided at both ends in the width direction of the tape-shaped composite 3. For example, as shown in FIG. The slits 4 at both ends in the width direction are inclined in the same direction, as shown in FIG. 3B, or the slits 4 at both ends in the width direction, as shown in FIG. May be provided inclining in opposite directions.

The slit 4 is defined by the length L (FIG. 2) of the tape-shaped composite 3 excluding the metal portions at both ends in the width direction and the width W (FIG. 2) of the ceramic superconductor layer 2 inside. It is desirable that the relationship be set so as to satisfy the following equation. (1/10) W≤L≤ (1/2) W When the length L is less than (1/10) W, there is no substantial effect, and the decrease in Ic due to the addition of bending strain increases. When the length L is equal to or more than (1/2) W, a portion having a small cross-sectional area is formed in the ceramic superconductor layer 2, and the current flows meandering around the slit 4 as shown by an arrow in FIG. Ic cannot be achieved. Also, if the width of the slit 4 is too large, the effect as a slit is reduced,
Further, the loss of the material cannot be ignored, so that it is better to be as narrow as possible. There is no particular limitation on the interval between the adjacent slits 4,
The selection may be made in consideration of the outer diameter of the conductor finally formed, the maximum bending strain during use, and the like.

The ceramic superconducting conductor of the present invention is suitable for the case where the tape-shaped composite 3 having a relatively wide width is vertically wrapped around the core material 5 for forming.

An example of the method for manufacturing a ceramic superconductor according to the present invention will be described. The conventional method can be directly applied to the production of the tape-shaped composite 3. For example, a metal-made pipe-shaped billet is filled with a raw material that can be used as a ceramic superconductor to form a composite billet, which is reduced in cross section to produce a tape-shaped composite body 3 having a predetermined shape and dimensions. When the width of the tape-shaped composite 3 is relatively wide, it is preferable to use a composite billet having a square cross section. Then, slits 4 are provided at both edges in the width direction of the tape-shaped composite 3 obtained by this method. In this case, for example, using a gear-shaped cutter,
Alternatively, it can be performed by punching or the like.

A desired number of the tape-shaped composites 3 having the slits 4 formed as described above are wound or wrapped around the outer periphery of the core material 5 as shown in FIG. 1, and the desired number of layers are laminated. Further, if necessary, a metal tape may be pressed and wound thereon. Thereafter, heat treatment is performed under predetermined conditions to obtain a ceramic superconductor (W & R).
Law). Alternatively, the tape-shaped composite 3 may be heat-treated before being wound or wrapped around the core material 5 and placed on the outer periphery of the core material 5 to produce a ceramic superconducting conductor (R
& W method). Further, to protect the ceramic superconducting conductor, it is also within the scope of the present invention to insert it into a corrugated pipe of, for example, Fe, SUS, Cu or the like.

[0017]

In the ceramic superconducting conductor of the present invention, as shown in FIG. 1, the slits 4 at both ends in the width direction of the tape-like composite 3 are wound around the core 5 when the tape-like composite 3 is covered. Since a large number of ceramic superconducting conductors are formed on the outer peripheral surface, flexibility is improved. As a result, even if bending distortion is applied to the superconducting conductors, deterioration in superconducting characteristics is small.

[0018]

Embodiment 1 An embodiment of the ceramic superconducting conductor of the present invention will be described below. Bi ₂ O ₃ , PbO, SrCO ₃ ,
Primary material powders such as CaCo ₃ and CuO are mixed in a molar ratio of Bi: P
b: Sr: Ca: Cu = 1.6: 0.4: 2: 2: 3, blended and mixed, then 800 ° C x 10 in air.
The resultant was temporarily calcined for 0 h and further pulverized to prepare a temporary calcined product. After CIP molding, it is inserted into an Ag pipe having a square cross section to form a composite billet, which is reduced in cross section and rolled to a width of about 60 mm (width of ceramic superconductor layer 2 is 50 mm) and thickness. is to prepare a ₀ · 25mm tape-like composite body 3. The tape-shaped composite 3 was provided with slits 4 having four types of lengths shown in Table 1 using a cutter or the like. As shown in FIG. 2A, the slit 4 is formed so as to open at both end surfaces m in the width direction of the tape-like composite 3 and in parallel with the width direction of the tape-like composite 3, and this is formed into a tape-like composite. A plurality of body-shaped members 3 are formed at both ends in the width direction in a zigzag manner at intervals of 30 mm.

On the other hand, an Ag pipe (core material 5) having an outer diameter of 20 mmφ and an inner diameter of 16 mmφ was prepared and corrugated. The tape-shaped composite material 3 was vertically wrapped around the outer periphery of the core material 5 and formed, followed by laminating 10 layers. This was subjected to a heat treatment at 840 ° C. × 100 h in the air to produce a ceramic superconductor. The ceramic superconducting conductor obtained in this manner is bent so as to have a radius of curvature of 1 m.
c was measured, and the results are summarized in Table 1.

[0020]

EXAMPLE 2 Using the same calcined powder and square Ag pipe as in Example 1, (width 26mm of the superconductor) width 30 mm, to prepare a tape-like composite body 3 having a thickness of ₀ · 25 mm. In the same manner as in Example 1, slits 4 having four kinds of lengths shown in Table 2 were provided by a cutter or the like. As shown in FIG. 2A, the slit 4 is also formed so as to open at both end surfaces m in the width direction of the tape-like composite 3 and in parallel with the width direction of the tape-like composite 3, and this is formed into a tape-like composite. The body 3 is formed in a plurality of zigzag shapes at both ends in the width direction at intervals of 15 mm.

The tape-shaped composite material 3 was vertically wrapped around the outer periphery of the same core material 5 as the core material 5 of Example 1 so as to form one layer with two sheets, and formed into a total of 10 layers. This was subjected to a heat treatment at 840 ° C. × 100 h in the air to produce a ceramic superconductor. In a state where these ceramic superconductors were bent to have a radius of curvature of 1 m, Ic was measured in liquid nitrogen in an environment of an O magnetic field, and the results were shown in Table 2.
Are shown together.

[0022]

Comparative Example 1 Tables 5, 6, and 7 are comparative examples with respect to Examples 1 to 4 in Table 1. Reference numerals 5 and 6 in the same table indicate that a slit 4 was formed in the same manner as the tape-shaped composite 3 of Example 1 to produce a ceramic superconducting conductor, and 5 indicates that the length L of the slit 4 was (1/10) W Smaller than 6
Is an experimental result when the length L of the slit 4 is larger than (1/2) W. 7 in the same table is an experimental result when the slit 4 was not formed in the tape-shaped composite 3. From this result, it can be seen that the ceramic superconducting conductor of Example 1 has little deterioration in superconducting characteristics even when bending strain is applied.

[0023]

Comparative Example 2 Tables 5, 6, and 7 are comparative examples with respect to Examples 1 to 4 in Table 2. Reference numerals 5 and 6 in the same table indicate that a slit 4 was formed in the same manner as the tape-shaped composite 3 of Example 2 to produce a ceramic superconducting conductor, and 5 indicates that the length L of the slit 4 was (1/10) W Smaller than 6
Is an experimental result when the length L of the slit 4 is larger than (1/2) W. 7 in the same table is an experimental result when the slit 4 was not formed in the tape-shaped composite 3. Similarly, from the results, it was found that the ceramic superconducting conductor of Example 2 had little deterioration in superconducting characteristics even when bending strain was applied.

Table 1

Table 2

[0026]

The ceramic superconducting conductor of the present invention has a simple structure, has little deterioration in superconducting characteristics against bending strain, and has a high Ic.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view showing one embodiment of a ceramic superconducting conductor of the present invention, and FIG. 1 (b) is a perspective view showing another embodiment of the ceramic superconducting conductor of the present invention.

2A is a top view showing an example of a tape-like composite in the ceramic superconducting conductor of FIG. 1, and FIG. 2B is a cross-sectional view thereof.

FIGS. 3A, 3B, and 3C are plan views showing various examples of a tape-like composite.

FIGS. 4A and 4B are perspective views showing different examples of a conventional ceramic superconductor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal layer 2 Ceramic superconductor layer 3 Tape composite 4 Slit 5 Core material

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsushi Hara 2-4-1, Nishi-Atsujigaoka, Chofu-shi, Tokyo Tokyo Electric Power Company R & D Laboratory (72) Inventor Hideo Ishii 2-4-1, Nishi-Atsujigaoka, Chofu-shi, Tokyo No. Tokyo Electric Power Company Technical Research Institute (56) References JP-A-64-65716 (JP, A) JP-A-1-204313 (JP, A) JP-A-2-92807 (JP, A) JP-A-2 −21512 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 12/00-13/00

Claims (1)

(57) [Claims] 1. A ceramic superconductor layer 2 in a metal layer 1.
Are provided at both ends in the width direction of the tape-shaped composite 3 provided with slits 4 at predetermined intervals in the longitudinal direction of the tape-shaped composite 3, and the tape-shaped composite 3 is provided with a metal pipe or rod. A ceramic superconducting conductor characterized in that a desired number of layers and a desired number of layers are vertically wrapped around an outer periphery of a core material 5 and the like.