JPH06349346A - Oxide superconductor for power transportation - Google Patents

Abstract

PURPOSE:To provide an oxide superconductor for power transportation capable of coiling and uncoiling with a superconductive characteristic kept by arranging a lubricant layer on the surface of a composite wire material comprising a metallic material and an oxide superconductor. CONSTITUTION:A composite wire material 12 consists of a metallic material (example: silver sheath 10) and an oxide superconductor 11. A stacked body 14 is formed by alternatively stacking the composite wire material 12 and a lubricant layer 13 (example: Teflon tape). The stacked body 14 is spirally wound at a specified interval on a cylindrical stainless steel former (support) 15 to form an oxide superconductor 16. By arranging the lubricant layer 13, friction between the composite wire materials or that between the composite wire material and the former produced when the oxide superconductor is coiled round a drum or uncoiled from it is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide superconducting conductor applicable to cables and the like.

[0002]

2. Description of the Related Art In recent years, YBaCuO system, BiSrCaC
Oxide superconductors such as uO type and TlBaCaCuO type which have a critical temperature (Tc) exceeding the liquid nitrogen temperature are known.

In order to apply such an oxide superconductor, molding of the oxide superconductor into various shapes has been studied. For example, when molding an oxide superconductor into a linear body, a metal sheath method is generally used. In this method, a metal pipe is filled with a raw material powder of an oxide superconductor, and the powder is reduced in diameter to a desired shape and size, and then heat treated. As the diameter reduction process performed here, it is possible to directly apply the conventionally used plastic working methods such as extrusion, drawing, swaging, and rolling according to the shape of the target linear body. it can.

Materials used for metal pipes include
Materials with excellent thermal and electrical conductivity, such as Ag, Ag
Alloys, Cu, Cu alloys, etc. can be applied. Among these, it is preferable to use Ag or Ag alloy having excellent oxygen permeability.

For example, as an oxide superconductor, Bi (22
In the case of using the 23) system or Tl system, a metal pipe is filled with an oxide superconductor or its raw material powder, and plastic working and heat treatment are performed at least once to produce a composite wire, which is single-core or multi-core. In this form, the oxide superconducting conductor is produced as it is or by pasting it on a former. The oxide superconducting conductor is wound on a drum, stored and transported in that state, and withdrawn as necessary.

[0006]

However, since unevenness appears on the surface of the heat-treated composite wire, when the oxide superconducting conductor is wound on the drum or pulled out from the drum, it may occur between the composite wires. The friction between the composite wire and the former becomes large, and the composite wire is locally loaded, which deteriorates the superconducting properties of the oxide superconductor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oxide superconducting conductor for electric power transportation which can be wound and drawn out while maintaining superconducting characteristics.

[0008]

The present invention is directed to a plurality of composite wire rods made of a metal material and an oxide superconductor, a support member for fixing the plurality of composite wire rods, and at least a part of the surface of the composite wire rod. The present invention provides an oxide superconducting conductor for electric power transportation, comprising:

Here, as the oxide superconductor, YBa
CuO type, BiSrCaCuO type, TlBaCaCuO
An oxide superconductor such as a system can be used. Further, as the metal material, Ag, Ag alloy, Cu, Cu alloy or the like can be used. Among these, it is preferable to use Ag or Ag alloy having excellent oxygen permeability.

As a method for obtaining a composite wire by combining a metal material and an oxide superconductor, a metal sheath method, a conform composite extrusion method or the like can be adopted.

As the supporting member for fixing the composite wire, a cylindrical SUS former, a copper former or the like can be used.

The material constituting the lubricating layer is a tape made of a crystalline resin such as Teflon (registered trademark) tape; a solid or liquid lubricant such as grease or lubricating oil; a resin such as a fluororesin. A layer or a layer composed of various fine particles can be used. Also, the lubricating layer is
The surface of the composite wire may be formed by braiding.

[0013]

The oxide superconducting conductor for electric power transportation of the present invention is characterized in that a lubricating layer is provided on the surface of a composite wire made of a metal material and an oxide superconductor.

The provision of the lubricating layer reduces friction between the composite wire rods or between the composite wire rods and the former when the oxide superconducting conductor is wound on the drum or pulled out from the drum.

Therefore, it is possible to prevent a local load from being applied to the composite wire at the time of winding and drawing out the oxide superconducting conductor. As a result, deterioration of superconducting properties of the oxide superconductor can be prevented.

[0016]

【Example】

Example 1 Bi ₂ O ₃ , PbO, SrCO ₃ , CaCO ₃ , CuO
The primary raw material of Bi: Pb: Sr: Ca: Cu = 1.6:
After blending and mixing so as to be 0.4: 2: 2: 3, calcination was performed in the air at 800 ° C. for 50 hours to prepare a calcined powder.

Next, the calcined powder was CIP-molded into a rod-shaped body having an outer diameter of about 15 mmφ, which was inserted into a silver pipe having an outer diameter of 25 mmφ and an inner diameter of 15 mmφ which was previously machined to obtain a composite billet. . The resulting composite billet is swaged to an outer diameter of 5 mmφ, then drawn to an outer diameter of 1.5 mmφ, and further rolled to a width of 3 m.
The tape-shaped body with m and 0.25 mm thickness was finished. afterwards,
This was heat-treated in the atmosphere at 835 ° C. for 50 hours to prepare a tape-shaped body 12 (composite wire) having the oxide superconductor layer 11 in the silver sheath 10 as shown in FIG. 1 (A).

Next, as shown in FIG. 1 (B), a laminated body 14 was prepared by alternately stacking five tape-shaped bodies 12 and Teflon tapes 13 (lubrication layers) having a thickness of 50 μm. 10
As shown in FIG. 1C, the individual laminated body 14 has an outer diameter of 40 mm.
It was spirally wound at a predetermined interval on the cylindrical SUS former 15 (support). The winding pitch in this case was 1 m. Thus, the oxide superconducting conductor 16 of the present invention was obtained.

For this oxide superconducting conductor 16, the DC critical current (Ic) in liquid nitrogen at 0 magnetic field and the DC critical current in liquid nitrogen after applying 0.5% bending strain were measured. . As a result, the reduction rate of Ic was about 10%. It is considered that this is because when the oxide superconducting conductor 16 was subjected to bending strain, the Teflon tape 13 suppressed the friction between the tape-shaped bodies 12 and did not apply a local load.

Example 2 A tape-like body 12 was produced in the same manner as in Example 1. Then, on the outside of the tape-shaped body 12, as shown in FIG.
A braided body 18 was produced by coating the alumina-based braid 17 of. Next, as shown in FIG. 2, the braid 18 was spirally wound on the former 15 while changing the winding direction for each layer. The winding pitch in this case was 1 m. Thus, the oxide superconducting conductor 19 of the present invention was obtained.

For this oxide superconducting conductor 19, the DC critical current (Ic) in liquid nitrogen at 0 magnetic field and the DC critical current in liquid nitrogen after applying 0.5% bending strain were measured. . As a result, the reduction rate of Ic was about 8%. It is considered that this is because when the oxide superconducting conductor 19 was subjected to bending strain, the alumina-based braid 17 suppressed the friction between the tape-shaped bodies 12 and did not locally apply a load.

Example 3 In the same manner as in Example 1, a tape-shaped body before heat treatment was produced. Then, as shown in FIG. 3, the tape-shaped body is coated with an alumina braid 17 having a thickness of 1 mm, and the braided body 1 is subjected to heat treatment at 835 ° C. × 60 hr in the atmosphere.
8 was produced. Next, as shown in FIG. 2, the braid 18 was spirally wound on the former 15 while changing the winding direction for each layer. The winding pitch in this case was 1 m. Thus, the oxide superconducting conductor of the present invention was obtained.

With respect to this oxide superconducting conductor, in liquid nitrogen, a DC critical current (Ic) and 0.5 at 0 magnetic field were used.
The DC critical current was measured at 0 magnetic field in liquid nitrogen after applying a bending strain of%. As a result, the decrease rate of Ic is about 4
%Met. It is considered that this is because when the oxide superconducting conductor was subjected to bending strain, the alumina-based braid 17 suppressed the friction between the tape-shaped bodies and did not locally apply the load.

Example 4 A tape-like body 12 was produced in the same manner as in Example 1. Next, as shown in FIG. 4, the surface of the tape-shaped body 12 is coated with a fluororesin 20 with a thickness of 0.05 mm, and then, as shown in FIG. The winding direction was changed every time and the spiral winding was performed. The winding pitch in this case was 1 m. Thus, the oxide superconducting conductor of the present invention was obtained.

With respect to this oxide superconducting conductor, in liquid nitrogen, a DC critical current (Ic) and 0.5 at 0 magnetic field were used.
The DC critical current was measured at 0 magnetic field in liquid nitrogen after applying a bending strain of%. As a result, the decrease rate of Ic is about 8
%Met. This is considered to be because when the oxide superconducting conductor was subjected to bending strain, friction between the tape-shaped bodies was suppressed by the fluororesin 20 and no load was locally applied.

Example 5 In the same manner as in Example 1, a wire-like body 21 was prepared which had been drawn. Next, as shown in FIG. 5, grease 22 is applied to the surface of the linear body 21, and then, as shown in FIG.
The braid 18 was spirally wound on the former 15 while changing the winding direction for each layer. The winding pitch in this case is 1
m. Thus, the oxide superconducting conductor of the present invention was obtained.

With respect to this oxide superconducting conductor, a DC critical current (Ic) and 0.5 at 0 magnetic field in liquid nitrogen
The DC critical current was measured at 0 magnetic field in liquid nitrogen after applying a bending strain of%. As a result, the decrease rate of Ic is about 1
It was 3%. It is considered that this is because when the oxide superconducting conductor was subjected to bending strain, friction between the linear bodies was suppressed by the grease 22 and no load was locally applied.

Conventional Example On the other hand, as a comparison, an oxide superconducting conductor was produced by a conventional method without providing a lubricating layer. With respect to this oxide superconducting conductor, the DC critical current in liquid nitrogen at 0 magnetic field and the DC critical current in liquid nitrogen after applying 0.5% bending strain in 0 magnetic field were measured.
It was 0 to 25%, which was a considerably large value.

[0029]

As described above, in the oxide superconducting conductor for electric power transportation of the present invention, since the lubricating layer is provided on the surface of the composite wire made of the metal material and the oxide superconductor, the composite wire is provided between the composite wires or the composite wire. The friction between the former and the former can be reduced, and the material can be wound and drawn out while maintaining the superconducting characteristics.

[Brief description of drawings]

FIG. 1A is a perspective view showing a tape-shaped body in one embodiment of the oxide superconducting conductor of the present invention, and FIG. 1B is a perspective view showing a laminated body in one embodiment of the oxide superconducting conductor of the present invention. , (C) are perspective views showing an embodiment of the oxide superconducting conductor of the present invention.

FIG. 2 is a perspective view showing another embodiment of the oxide superconducting conductor of the present invention.

FIG. 3 is a perspective view showing a braided body in another embodiment of the oxide superconducting conductor of the present invention.

FIG. 4 is a perspective view showing a tape-shaped body in another embodiment of the oxide superconducting conductor of the present invention.

FIG. 5 is a perspective view showing a linear body in another embodiment of the oxide superconducting conductor of the present invention.

[Explanation of symbols]

10 ... Silver sheath, 11 ... Oxide superconductor layer, 12 ... Tape-like body, 13 ... Teflon tape, 14 ... Laminated body, 15 ...
Former, 16, 19 ... Oxide superconducting conductor, 17 ... Alumina braid, 18 ... Braid, 20 ... Fluororesin, 21
... linear body, 22 ... grease.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuzo Tanaka 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Tsukushi Hara 2 Nishitsutsujigaoka, Chofu-shi, Tokyo 4-1-1 TEPCO Technical Research Institute (72) Inventor Hideo Ishii 2-4-1 Nishitsutsujigaoka, Chofu-shi, Tokyo TEPCO Technical Research Institute

Claims (1)

[Claims] 1. A plurality of composite wire rods made of a metal material and an oxide superconductor, a support member for fixing the plurality of composite wire rods, and a lubricating layer provided on at least a part of the surface of the composite wire rod. An oxide superconducting conductor for electric power transportation, comprising: