JPS63276810A - Superconductive wire - Google Patents

Abstract

PURPOSE:To prevent cracks from being generated at a superconductive layer part even if bending stress is exerted there and to make this wire thin by disposing a core made of super-plastic ceramic inside the superconductive layer part made of an oxide group superconductor. CONSTITUTION:A superconductive wire A is formed of the following parts: a core 1 made of super-plastic ceramic, a superconductive layer part 2 which covers this core 1 and is made of an oxide group superconductor, a coating layer 3, and a stabilized layer 4. The core 1 is composed of super-plastic ceramic such as partially stabilized zirconia which is stabilized by adding a prescribed second element into zirconia ceramic, and this core is very large in its bending strength and high in its tenacity. The superconductive layer part 2 is formed of an oxide group superconductor of either A-B-Cu-O system or A-B-Ox system. The superconductive layer part 2 is thus reinforced by the core 1, and hence rigidity of the wire itself can be enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a superconducting wire with improved flexibility.

"Conventional technology" Recently, the critical temperature at which the normal conductive state transitions to the superconducting state (
Various superconducting materials made of oxide ceramics exhibiting a high value of Tc) higher than the liquid nitrogen temperature are being discovered. This type of superconducting material has a higher critical temperature than conventional alloy-based superconducting materials or intermetallic compound-based superconducting materials, and can be used under more favorable cooling conditions, so it is considered to be an extremely promising superconducting material in practical use. There is.

Incidentally, an example of the structure of a conventional superconducting wire manufactured using this type of superconducting material is shown in FIGS. 4 and 5. The superconducting wire B shown in FIGS. 4 and 5 is a cladding tube made of a non-magnetic, good conductor metal material such as stainless steel. A conductor 12 made of an oxide-based ceramic superconducting material is provided inside.

[Problems to be Solved by the Invention] The superconducting wire B is an excellent superconducting wire that transitions to a superconducting state at a much higher temperature than conventional alloy-based or intermetallic compound-based superconducting wires. It can be used under extremely advantageous cooling conditions compared to other superconducting wires. However, the superconducting wire B having the above structure has the disadvantage that the conductor 12 made of the superconductor is extremely brittle and lacks flexibility, and when bending stress is applied to the superconducting wire B, the conductor 12 is extremely fragile. 2 has the problem of being prone to cracking.

The present invention has been made in view of the above problems, and provides a superconducting wire having a structure in which cracks do not occur in the superconducting layer portion made of a superconductor even when bending stress is applied, and the wire can be thinned. The purpose is to

"Means for Solving the Problems" In order to solve the above problems, the first invention provides a superconducting layer section made of an oxide-based superconductor, and a superplastic ceramic provided inside the superconducting layer section. A core body consisting of.

In order to solve the above-mentioned problems, a second invention provides a superconducting layer section made of an oxide-based superconductor, a core made of superplastic ceramic provided inside this superconducting layer section, and a superconducting layer section made of a superconducting layer section. A stabilizing layer made of a highly conductive metal material is provided on the outside of the conductive material.

``Operation'' A core made of superplastic ceramics with high bending strength and toughness is placed inside the superconducting layer made of superconductor to improve rigidity and create a structure that can resist bending stress. Also,
It is possible to coat the outer surface of a core made of superplastic ceramics with a superconductor in the form of a thin film, and by applying this coating it is possible to form a conductor made of superconductor on the outer surface of a thin core. , it becomes possible to thin this type of superconducting wire.

``Example'' FIGS. 1 and 2 show a superconducting wire according to an example of the present invention. The superconducting wire A of this example includes a core 1 made of superplastic ceramics, and a core 1 made of superplastic ceramics. a cylindrical superconducting layer portion 2 made of an oxide-based superconductor provided covering the superconducting layer portion 2; a covering layer 3 provided covering the superconducting layer portion 2;
It consists of 1 m4 of stabilization provided over the

The core 1 is made of superplastic ceramic such as partially stabilized zirconia, which is stabilized by adding a second element such as MgO, Y, or 03 to zirconia ceramic represented by ZrO, and has a high bending strength. It is extremely large and has high toughness.

The superconducting layer portion 2 is made of A-B-Cu-0 system (however,
A is the periodic table nIa of La, Ce, Y, Sc, Yb, etc.
from an oxide-based superconductor of group elements IN or higher, where B represents one or more alkaline earth metal elements such as Sr and Ba, or BaP bI3 io s, S r
T i O* 1n aT io s, (Sr, Ba)
A − such as Ties, (Ca, S r) TiOs
It is formed from a B-Ox type oxide superconductor.

On the other hand, the coating layer 3 is made of a high-strength, non-magnetic, heat-resistant metal such as stainless steel, and is suitable for the heat treatment described below for firing the oxide-based superconducting ceramic constituting the superconducting layer portion 2. It is something that can be endured. Further, the stabilizing layer 4 is made of a highly conductive metal material such as copper, and serves as a conductor through which current flows when the superconducting layer portion 2 made of a superconductor transitions to a normal conductive state for some reason. This is to stabilize the superconducting wire.

In the superconducting wire A having the above structure, the diameter of the core l is, for example, about 0.5 mm, and the outer diameter of the superconducting layer portion 2 is, for example, 1 m.
The thickness of the covering layer 3 is, for example, about 0.11 mm, and the thickness of the stabilizing layer 4 is, for example, about 0.1 to 0.51 mm.

Next, an example of a method for manufacturing the superconducting wire A will be described.

To manufacture superconducting wire A, a core l made of superplastic ceramics such as partially stabilized zirconia is inserted into a stainless steel pipe with a diameter of about 10 to 3 (Jam), and the stainless steel pipe and core l are connected. A raw material powder of an oxide-based superconducting material is filled in between.

When producing A-B-Cu-0 series superconducting ceramic material, this raw material powder is composed of compound powder of element A (oxide powder, chloride powder, carbonate powder, etc.), compound powder of element B, and copper oxide. A mixed powder of powders is used, a superconducting powder formed by pulverizing a superconductor, or a mixed powder of the above mixed powder and superconducting powder is used.

Next, the stainless steel vibrator filled with the raw material powder was
The raw material powders are heated to ~1100° C. for about 1 to 300 hours to react with each other, and a superconductor is generated between the core body 1 and the stainless steel pipe to form a conductor. Thereafter, the entire wire is subjected to diameter reduction processing to obtain a wire having a diameter of approximately II, which is provided with a superconducting layer portion 2 made of a superconductor between the core body 1 and the coating layer 3. Thereafter, the outer surface of the covering PJ3 is covered with a copper layer to obtain a superconductor wire A.

Moreover, in order to manufacture the superconductor wire A, the method described below may be adopted. That is, diameter 0.5m++
A thin film-like superconducting layer made of superconducting ceramic is formed on the outer surface of a core made of superplastic ceramic using a method such as CVD or plasma spraying, and copper is further formed on the outer surface using plasma spraying or dip forming. A superconducting wire is manufactured by forming a stabilizing layer consisting of: In addition, according to this manufacturing method, since the outer surface of the core made of superplastic ceramics can be coated with a superconductor, a superconducting layer made of a thin film-like superconductor can be formed, and a small diameter superconducting wire can be formed. can be manufactured.

In the superconducting wire A having the above structure, the core 1 is made of superplastic ceramics, and the superconducting layer portion 2 is reinforced by the core 2, so that the rigidity of the wire itself is as shown in FIGS. 3 and 4. It is larger than conventional metal-coated superconducting wire. Therefore, the conductor 2 becomes 1ζ so that it can resist bending stress, and the risk of cracks occurring in the conductor 2 can be reduced.

FIG. 3 shows a superconducting wire according to the second invention, and the superconducting wire A' shown in FIG. 3 has a structure in which the coating layer 3 of the superconducting wire A shown in FIG. 1 is omitted.

Even in the superconducting wire A' having such a structure, the superconducting l
It is possible to obtain an effect V equivalent to that of QA.

By the way, a large number of superconducting wires A of this embodiment can be assembled and inserted into the inside of the outer sheath to reduce the diameter and form a multi-strand.

"Effects of the Invention" As explained above, the superconducting wire of the present invention has a superconducting layer made of an oxide-based superconductor between the core made of superplastic ceramics and the stabilizing layer made of a nonmagnetic good conductor. This is a superconducting wire with a conventional structure in which the outer periphery of the superconductor is covered with a metal coating layer, because the center of the brittle superconducting layer made of superconductor is reinforced with superplastic ceramics that have high rigidity and toughness. It has higher rigidity and better resistance to bending stress than the superconducting layer, and there is less risk of cracking in the superconducting layer. In addition, if a superconducting ceramic layer is coated on the surface of a core made of superplastic ceramics, it becomes possible to form a superconducting layer of a superconductor on the outer surface of a small-diameter core, making it possible to make superconducting wires thinner. It has the effect of

[Brief explanation of drawings]

Figures 1 and 2 show one embodiment of the present invention; Figure 1 is a cross-sectional view, Figure 2 is a longitudinal sectional view, and Figure 3 is another embodiment of the present invention. 4 and 5 show conventional superconducting wires, FIG. 4 is a cross-sectional view, and FIG. 5 is a vertical cross-sectional view. A, A'... superconducting wire, 1... core, 2... superconducting layer part,
3...Insulating coating layer, 4...Stabilizing layer.

Claims (2)

[Claims] (1) A superconducting wire comprising a superconducting layer made of an oxide superconductor and a core made of superplastic ceramic provided inside the superconducting layer. (2) A superconducting layer made of an oxide superconductor, a core made of superplastic ceramics provided inside this superconducting layer, and a highly conductive metal material provided outside of the superconducting layer. A superconducting wire characterized by comprising a stabilizing layer consisting of.