JPH05182535A - Ceramics superconductor - Google Patents

Abstract

PURPOSE:To provide such a ceramics superconductor manufactured through a react-winding process that the superconducting property of each of tape-shaped superconducting wires being wound round the periphery of a former may hardly be deteriorated. CONSTITUTION:In a ceramics superconducting conductor manufactured through the process of winding and arranging tape-shaped superconducting wires 3 each comprising a superconducting 1 and metal 2 compounded with each other on a former 4, the tape-shaped superconducting wires 3 are wound and arranged on the former 4 in such a manner that the bending distortion factor of each of the superconducting wires 3 applied in the cross direction thereof may be kept within 2% and also the bending distortion factor of the wire rod applied in the longitudinal direction thereof may be kept within 0.5%.

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 transportation such as a cable for power transportation.

[0002]

2. Description of the Related Art In recent years, ceramic superconductors having a Tc higher than the temperature of liquid nitrogen, such as Y-based, Bi-based, and Tl-based, have been known. Aiming at application (use) of such ceramic superconductors to various fields, molding into various shapes has been studied.

For example, when manufacturing a wire rod, a metal sheath method is generally used. This is to fill a metal pipe with a ceramic raw material to be a superconductor into a composite billet, and then reduce the cross section of the composite billet to finish it into a composite wire with a desired shape and size, and then heat-treat it to obtain a ceramic superconducting conductor. It is a thing.

The obtained wire has a round cross section,
Multifilamentary wire having an elliptical shape, a quadrangular shape, a tape shape, or a shape obtained by bundling a plurality of these, or a multilayer structure in which a ceramics superconductor is concentrically or spirally arranged inside a metal. Various prototypes of wire rods are being studied.

As the above-mentioned cross-section reduction processing, the conventional plastic working methods such as extrusion, rolling, drawing and swaging are applied as they are according to the shape of the wire to be obtained.

As a material of the metal and the metal sheath which are composited with the superconductor, a material excellent in thermal conductivity and electric conductivity,
For example, Ag, Ag alloy, Cu, Cu alloy and the like can be applied, but Ag and Ag alloy are often used in terms of oxygen permeability and oxidation resistance.

In recent years, application of the above ceramic superconducting conductors for electric power transportation such as cables has been studied. Specific examples thereof include those shown in FIGS. 2 and 3.

In the structure shown in FIG. 2, a metal tape a is filled with a ceramics superconductor b, and a comparatively narrow composite tape wire c made by subjecting the metal superconductor b to a cross-section reduction process is formed on the outer periphery of the former d. It is made by winding a number of sheets, assembling them, and making a multilayer.

As shown in FIG. 3, a metal tape a is filled with a ceramics superconductor b, and a comparatively wide composite tape wire c made by subjecting the metal superconductor b to cross-section reduction processing is formed on the outer periphery of the former d. There are two sheets per layer and multiple layers.

Conventionally, as a method of manufacturing a ceramics superconducting conductor having such a structure, a desired number of layers and a desired number of layers of a composite tape wire c produced by an ordinary metal sheath method are wound around an outer periphery of a former d. A wind-react method in which a heat treatment is performed after the application is common. However, since it is difficult to manufacture a long ceramic superconducting conductor by this method, recently, a desired number of composite tape wires (tape-shaped superconducting wires) preliminarily heat-treated are formed on the outer periphery of the former. A method of winding layers (react wind method) is being studied.

[0011]

When a ceramic superconducting conductor is manufactured by the above-mentioned reactor winding method, excessive bending strain is added to the tape-shaped superconducting wire when it is wound around the former, and the superconducting characteristics are deteriorated. There was a drawback.

An object of the present invention is to prevent the superconducting characteristics of the tape-shaped superconducting wire wound around the outer periphery of the former from being easily deteriorated in the ceramic superconducting conductor manufactured by the reactor winding method.

[0013]

The ceramic superconducting conductor of the present invention has been obtained as a result of various experiments for improving the above-mentioned drawbacks. As shown in FIG. In a ceramics superconducting conductor formed by spirally winding a tape-shaped superconducting wire 3 formed by compounding the above, a bending strain rate applied to the tape-shaped superconducting wire 3 in the width direction thereof. Is within 2%, and the bending strain applied in the length direction is within 0.5%.

The ceramic superconducting conductor of the present invention is manufactured as follows. First, a tape-shaped superconducting wire 3 in which a ceramic 1 and a metal 2 which are superconducting conductors are combined.
To produce. As the method, the conventional metal sheath method can be applied as it is. For example, a ceramic raw material has a round cross section,
Filled in a metal pipe such as a square type to make a composite billet,
This is subjected to cross-section reduction processing to finish into a composite tape having a desired shape and size. There is no problem even if heat treatment is performed during the cross-section reduction processing.

There is no restriction on the width and thickness of the obtained composite tape. The obtained composite tape is heat-treated to form a tape-shaped ceramic superconductor (tape-shaped superconducting wire 3). A long ceramic superconducting conductor can be obtained by, for example, heat-treating the tape-shaped superconducting wire 3 wound around a heat-resistant bobbin in advance.

As shown in FIG. 1, the tape-shaped superconducting wire 3 thus manufactured is wound around the outer periphery of the former 4 in a desired number of layers and a desired number of layers. In this case, there is no restriction on the number of layers. There is no restriction on the number of sheets per layer, but if the number is too small, the flexibility of the ceramic superconducting conductor obtained will decrease, so three or more sheets are desirable.

The material of the former 4 is not limited, and metal pipes or round bars such as Cu, AI, Fe and SUS, and plastics such as nylon, Teflon and polyethylene can be applied. The former 4 is made to have flexibility by, for example, corrugating the former 4 or winding the tape in a spiral shape to form the former 4. It's good to leave.

Tape-shaped superconducting wire 3 for forming the frame 4
In the winding step, the tape-shaped superconducting wire 3 is placed on the former 4 so that the bending strain rate applied in the width direction is within 2% and the bending strain rate applied in the length direction is within 0.5%. It is arranged in a spiral shape. When the bending strain rate applied in the width direction of the tape-shaped superconducting wire 3 is 2% or more, and when the bending strain rate applied in the length direction is 0.5% or more, both are superconducting of the tape-shaped superconducting wire 3. Many cracks occur in the body (superconducting layer) 1 and the superconducting properties are deteriorated.

In the ceramic superconducting conductor of the present invention,
After winding the tape-shaped superconducting wire 3, a metal tape made of Ag, Cu, Al or the like, or a tape 5 made of plastic tape or the like is spirally pressed and wound thereon as shown in FIG. It is preferable to fix the whole by inserting it into a pipe made of metal or plastic to protect the whole.

[0020]

In the ceramic superconducting conductor of the present invention, the tape-shaped superconducting wire 3 has a bending strain rate of 2% or less in the width direction and a bending strain rate of 0.5% or less in the length direction. -Because it is wound around the outer periphery of the marker 4, even if bending is added to the ceramics superconducting conductor, it is within the permissible range, so that the superconducting characteristics are not significantly deteriorated and the high I
The ceramic superconducting conductor of c can be obtained.

[0021]

EXAMPLES The ceramic superconducting conductor of the present invention will be specifically described below based on examples. First, Bi ₂ O
₃ , PbO, SrCO ₃ , CaCO ₃ , CuO and other primary raw material powders in a molar ratio of Bi: Pb: Sr: Ca: Cu = 1.
The components were blended so as to be 6: 0.4: 2: 2: 3, mixed, and then calcined in the atmosphere at 800 ° C. for 50 hours to produce a calcined powder. This was CIP molded into a rod-shaped body having an outer diameter of 14.5 mmφ.

This rod-shaped body was prepared in advance with an outer diameter of 25 mm.
φ, inner diameter 15 mmφ, length 100 mm inserted into Ag pipe (metal pipe) 1 to form a composite billet, which is swaged and rolled to a thickness of 0.3.
mm, width 15 mm, finished into a tape-shaped wire. In addition,
When the thickness was 0.5 mm, the intermediate heat treatment was performed at 835 ° C. for 50 hours.

The tape-shaped wire thus obtained was subjected to 835 ° C. ×
Heat treatment was performed for 50 hours to obtain a tape-shaped superconducting wire 3.
Seven tape-shaped superconducting wires 3 are wound around the outer circumference of the former 4 as shown in FIG. 1 so as to have various bending strain rates as shown in Table 1, and a silver tape is provided on the outside thereof. 5 was pressed and wound to produce a ceramics superconducting conductor.

The Ic measurement results of the ceramic superconducting conductor thus obtained are shown below. As is clear from Table 1, ε ₁ =
2.0%. I having a bending strain rate of ε ₂ = 0.5% or more is I
c decreases.

[0025]

[Table 1]

[0026]

The ceramic superconducting conductor of the present invention has excellent Ic characteristics, can be elongated, and is suitable as a cable conductor.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a ceramics superconducting conductor of the present invention.

FIG. 2 is an explanatory view showing an example of a conventional ceramics superconducting conductor.

FIG. 3 is an explanatory view showing another example of a conventional ceramics superconducting conductor.

[Explanation of symbols]

 1 Superconductor 2 Metal 3 Tape-shaped superconducting wire 4 Former

Claims (1)

[Claims] 1. A ceramic superconducting conductor in which a tape-shaped superconducting wire 3 composed of a composite of a superconductor 1 and a metal 2 is wound around a former 4 in a spiral shape, wherein The superconducting wire 3 is arranged on the former 4 so that the bending strain rate applied in the width direction thereof is within 2% and the bending strain rate applied in the length direction thereof is within 0.5%. Ceramics superconducting conductor.