JPH012219A - Manufacturing method of ceramic superconducting wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing a ceramic superconducting wire used for power cables, magnets, power storage links, etc.

[Conventional technology and its problems]

Recently, it has a high critical temperature (L a S rlzc
uOa, (S c S r) zc u 04, (L
a B a)zc u 04, YBa, Cu, O, -δ
, Y, Ba2Cu307-δ, DyBazcuso, -
Ceramic superconductors such as δ and LiTizOa are attracting attention, but these cannot be plastically worked like metal materials, and to obtain these wires, powder metallurgy or vapor phase growth methods such as PVD are required. However, the former requires many steps from manufacturing the powder to sintering, and the heating process in the middle of the process requires the entry and exit of constituent elements such as oxygen.
Since the composition and structure change easily, the manufacturing conditions must be managed 1iiiI.
It has to be carried out closely, which has the disadvantage of poor productivity and economy. In addition, PVD is unsuitable for producing long products for processing in vacuum, and the product is compositionally unstable due to reduction, and the deposition yield of evaporated elements is low, resulting in a rapid deposition rate. Since the process is slow, there are problems such as poor productivity.

c.Means and effects for solving problems] The present invention has the following features:
The product was leaked in such a situation, and its purpose was to create ceramics 8! whose composition and structure were strictly controlled. The object of the present invention is to provide a manufacturing method that allows highly efficient mass production of conductive wires.

That is, the present invention heats and decomposes a raw material liquid in which the constituent elements of a superconductor are dissolved using plasma, reacts and generates superconductor fine powder, and causes the superconductor fine powder to coagulate and adhere on a desired number of traveling substrates. This is then cooled and then heat treated.

The present invention will be specifically explained below with reference to the drawings.

FIG. 1 is a conceptual diagram showing an example of an apparatus for implementing the present invention. A desired number of substrates 1 such as wires and strips are supplied from an uncoiler 2 and guided to a reactor 3.

In the reactor 3, the raw material liquid supplied from the nozzle 4 is heated by the plasma 5, decomposed and reacted to produce superconductor fine powder, which adheres to the traveling base 1 and flows into the cooling chamber 6 and heating furnace 7. After that, it is wound up by the recoiler 8.

In the upper part, the base l contains carbon fiber, Mo, S
A heat resistant material such as US is used. The raw material liquid is a compound containing constituent elements of the superconductor, such as Y, in water or an organic solvent.
Chlorides such as Cl 3 , Ba Cl z , CuCl, etc. are dissolved in a predetermined molar ratio. In addition to metal salts, elements such as halogen and chalcogen can also be contained as solution components and incorporated into the superconductor. Optimum values for the composition and concentration of the raw material liquid are determined through preliminary experiments.

When manufacturing an oxide-based superconductor, it is preferable to use oxygen as the plasma discharge gas because the oxygen concentration in the superconductor remains stable at a high level, but halogen gas or inert gas may also be used.

In order to improve the adhesion of the superconductor fine powder, it is preferable to preheat the substrate, but when the substrate travels at a slow speed,
There is no need to do this as the substrate will be sufficiently heated while passing through the reactor. However, if the substrate is moving at a high speed, it is advisable to place a preheating furnace in front of the reactor to perform preheating. The temperature is preferably lower than the plasma processing temperature, because it is thought that the superconductor fine powder coagulates and adheres to the substrate in the plasma heating section because the substrate temperature is lower than that in the plasma heating section. Note that the adhesion and adhesion amount of superconductor fine powder to the substrate vary depending on the preheating temperature of the substrate.According to the experimental results of the inventors, the preferable preheating temperature of the substrate is 600"C below the plasma treatment temperature.
is within the range of The superconducting properties may be maximized by heat-treating the superconductor fine powder-adhered substrate, which has cooled after exiting the reactor, through a heating furnace. In other words, the superconductor produced by reaction in the high temperature region of the plasma heating section is in an equilibrium or quasi-planar state at high temperature, and has a composition such as Ot, crystal &
l is not necessarily in an optimal state, and this adjustment is made during the heat treatment using this heating furnace.

This heating furnace is maintained at a lower temperature than the plasma heating section and is designed to provide an oxidizing, reducing, etc. atmosphere.

In addition, by placing a cooling chamber immediately after the exit of the reactor and cooling the substrate to which the superconductor is attached, it is possible to suppress coarsening of the superconductor crystals and harmful reactions between the superconductor and the substrate, resulting in a high-purity, dense structure. This is effective because it can form a fine structure. In addition, the refrigerant for cooling at this time may be air, inert gas, water,
Organic solvents can be used.

In the present invention, a wire rod with excellent superconducting properties is stably produced by passing the substrate to which the superconductor is attached after leaving the reactor through a cooling chamber and a heating furnace.

A further advantage of the present invention is that in the normal CVD method, gaseous raw materials are individually supplied and reacted, so when manufacturing a multi-component superconductor, many reaction combinations are possible. Since substances other than the intended superconductor are generated and included, the superconducting properties of the obtained superconductor tend to deteriorate.

On the other hand, according to the method of the present invention, since the raw materials are blended in a predetermined ratio in advance, reactions other than the intended ones are largely suppressed. Furthermore, this type of multi-component superconductor has crystal anisotropy in its electrical properties, and the series of processes of the present invention are carried out with this point in mind.

Further, in the method of the present invention, by using a plurality of raw material liquid supply nozzles and a plurality of plasma torches, a large number of substrates can be processed simultaneously.

As described above, the reaction generation, adhesion, and cooling of superconductor fine powder on the substrate.
Although we have explained by performing the heat treatment process one time at a time,
It is possible to increase the thickness by repeating this operation multiple times. In addition, providing a buffer layer on the substrate in advance to suppress the reaction with the superconductor, and coating the surface layer with a non-superconducting substance for the purpose of protecting and stabilizing the superconductor improve the superconducting properties of the resulting superconductor. It is valid in points.

〔Example〕

The present invention will be explained in detail below using examples.

The first Y-Ba-Cu-0 ceramic superconducting wire
It was manufactured using the equipment shown in the figure. The base contains Y2O,
A 50 μφ carbon fiber coated with 2 μ of a mixed oxide of ZrO and ZrO was used. The raw material liquid contains Y, Cl s
, B a CI z , and Cu CI z in a molar ratio of 1:2:3, respectively, were dissolved in an aqueous solution of 8.5%.

A 0□ gas plasma was used as the plasma, and a plasma torch 9 and a nozzle 4 for supplying the raw material mixture were arranged in five rows on the left and right in the reaction furnace 3, forming a plasma heating section. 100 bases are run simultaneously using the device with the above configuration,
After preheating this to 500°C in front of the reactor, reactor 3
I let it pass inside.

The passage time of the substrate through the plasma heating section was 45 seconds, and the substrate temperature at the exit of the reactor was approximately 480°C.The substrate with the superconductor attached thereto was then cooled with water in a cooling chamber, and then heated with airflow in a heating furnace. A heat treatment was performed at 750° C. for 5 minutes to obtain a superconducting wire.

Example 2 A superconducting wire was obtained in the same manner as in Example 1 except that the wire was not cooled after leaving the reaction chamber.

Example 3 A superconducting wire was obtained in the same manner as in Example 1, except that no heat treatment was performed after leaving the cooling chamber.

Comparative example For comparison, samples were manufactured using the following conventional method.

Comparative Example 1 A superconducting wire was obtained by sputtering on the same substrate as in Example for 1 hour using a magnetron sputtering device using an oxide superconductor of Y Bat Cu 301 as a target. The base temperature is 600℃ and the degree of vacuum is 0.1T.
It was set as orr.

The critical temperature (Tc) and critical current density (Jc) of the four types of superconducting wires obtained in Examples 1 to 3 and Comparative Example were measured. The results are shown in the first table, including the superconductor adhesion thickness.
Shown in the table.

Table 1 As is clear from Table 1, the method of the present invention (Examples 1 to 3)
) has a higher Tc5Jc than the comparative method product (Comparative Example-1), and in particular, the product that was cooled and heat-treated after leaving the reactor (Example-1) had a J.

shows the highest value.

Further, the deposition speed of the superconductor of the present invention is 300 times or more compared to the conventional method shown in the comparative example, and the present invention can process a large number of superconductors at the same time, resulting in high productivity.

〔effect〕

As described above, according to the present invention, Tc, J.

Ceramic superconducting wires with excellent properties such as these can be produced in a pickled manner, resulting in significant industrial effects.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing an example of an apparatus for implementing the present invention. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Uncoiler-13... Reactor, 4... Nozzle, 5... Plasma, 6...
Cooling room, 7...Heating furnace, 8...Recoiler, 9
...Plasma torch.

Claims (4)

[Claims] (1) The raw material liquid in which the constituent elements of the superconductor are dissolved is thermally decomposed by plasma to react and generate superconductor fine powder, and this superconductor fine powder is coagulated and deposited on a desired number of moving substrates. 1. A method for producing a ceramic superconducting wire, which comprises cooling the material and then subjecting it to heat treatment. (2) The method for manufacturing a ceramic superconducting wire according to claim 1, wherein the plasma uses oxygen gas as a discharge gas and the manufactured superconductor is an oxide-based superconductor. (3) Raw material liquid is supplied from multiple nozzles, and is subjected to plasma thermal decomposition using multiple plasma torches to react and generate superconductor fine powder, which is coagulated and adhered onto multiple substrates. A method for manufacturing a ceramic superconducting wire according to claim 1, characterized in that: (4) The method for manufacturing a ceramic superconducting wire according to claim 1, wherein the substrate is supplied after being preheated to a temperature lower than the plasma temperature.