JPH01255695A - Production of superconductor - Google Patents

Abstract

PURPOSE:To produce a Bi-Sr-Ca-Cu-O type oxide superconductor with a desired substrate by sintering end pulverizing starting material for the superconductor having a prescribed compsn., dispersing the resulting powdery material in a solvent and electrodepositing the material on an electrode by electrophoresis. CONSTITUTION:Starting material for the superconductor having the prescribed compsn. consisting of Bi2O3, SrCO3, CaCO3 and CuO is sintered and pulverized with a ball mill or the like. The resulting powdery material is dispersed in the solvent and an electrifying agent and a dispersant are added as required. The powdery material is then electrodeposited on a substrate electrode by electrophoresis with the prepd. dispersion liq. to obtain the Bi-Sr-Ca-Cu-O type oxide superconductor. The substrate may be made of a metal, plastics, glass or ceramic and may have a plate or wire shape.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention is directed to the production of B i -3r -Ca by electrophoresis.
-Relates to a method for producing a Cu-0 based oxide ffi conductor.

(Prior art) In recent years, B1-3r-Ca has been developed as a type of oxide superconductor.
-Cu-0 type superconductor was developed, but this superconductor also
Like other oxide superconductors, it has poor processability, so it is unclear how to make practical wires, thin films, and plates.
This has become an important issue. Conventionally, methods for producing superconductors include sputtering, in which superconductor raw materials are calcined and crushed, then press-formed and then sputtered onto a substrate, and superconductor raw materials are calcined, crushed and then kneaded into a paste, which is then kneaded into a paste and screen-printed onto a substrate. There are, however, a screen printing method in which the superconductor raw material is calcined and then pulverized, and then dispersed in a solvent and applied to a substrate, and then a solvent coating method in which the material is calcined.

(Problems to be Solved by the Invention) However, although the sputtering method can produce 17 uniform superconductors regardless of the shape of the substrate, it is inferior in continuous workability. On the other hand, the screen printing method and the molten aluminium coating method are superior to the sputtering method in terms of continuous workability, but if the substrate is uneven, it is difficult to create a uniform superconductor, and when firing, It is necessary to remove the solvent almost completely by drying.

(Means for solving the problem) Therefore, the applicant should: 1. @! After calcining the raw material for conductor,
It is ground and dispersed in a solvent, and then subjected to electrophoresis. A method of electrodepositing on the Ii electrode and firing, and after firing the superconductor raw material, pulverizing it and dispersing it in a solvent, and then electrodepositing it on the electrode by electrophoresis to create a superconductor. developed a method.

Electrophoresis in this method is usually performed by blending superconductor raw materials to the desired composition, calcining F& or final firing, and then pulverizing into a fine powder of 0.1 to 50 μm using a ball mill or the like.
It is dispersed in an organic solvent (e.g., alcohol, ketone, etc.) containing a charging agent or dispersant, and electrodeposited on a conductive heat-resistant substrate such as a silver plate at a thickness of 200 to 700 cm. Since it is performed by electrophoresis, even if the substrate has irregularities, grooves, holes, etc., the electrodeposition can be applied uniformly to those areas. Further, if electrophoresis is performed using a method such as barrel plating, it can be performed continuously. Furthermore, since calcined superconductor materials are electrodeposited by electrophoresis, they do not contain much solvent, so they are almost the same as those molded by pressing, so they can be molded immediately without pre-drying. It can be made into a book.

However, these methods can be applied to B i -Sr -Ca -
When applied to Cu-0 superconductors, unexpected effects were discovered.

Y-Ba-Cu-0 superconductors are superconducting and unstable against moisture, but Di-Sr-Ca-Cu-0 superconductors are stable against moisture and are stable during electrophoresis. Can electrophoresis be performed even if the organic solvent used contains some water? It exhibits superconductivity just by exposing it to Il.

That is, even if solvents such as alcohol and acetone are sufficiently purified, they still contain some water. Furthermore, when using iodine or the like as a charging agent, charging performance is better if it contains some moisture. When moisture is contained in the solvent as described above, the Y-[]]a-Cu-0 system m-conductor, which is unstable in moisture, does not exhibit superconductivity unless it is subjected to firing after electrodeposition. The i-Sr-Ca-Cu-0 system superconductor does not require a final firing island if the raw material is fired on the electrodeposited surface, but it shows superconductivity with a light firing. be. In particular, when electrophoresis is performed at a high voltage (500 to 700 V), high strength can be obtained even though final firing is not performed.

The firing of the raw material in the present invention is performed until the diffraction pattern of the material Xm after firing matches the diffraction pattern of an oxide superconductor that has been prepared in advance and exhibits good superconductivity. In addition, if it is preferable to perform heating after electrodeposition, heating at 400 to 500°C in a high concentration oxygen atmosphere or oxygen atmosphere, or heating by laser beam irradiation in the same atmosphere or air. All you have to do is follow.

(Example) Example I D:zOi, 5rCO0, CaCO3 and CuO in molar ratio Bi:Sr:Ca:Cu=1:1:1
: 2, baked in air at 950℃ for 8 hours and 450℃ for 4 hours, cooled,
I did line diffraction. The X-ray diffraction pattern of this fired material matched the diffraction pattern of B15rCaCuJx superconductor, which exhibits superconductivity.

Therefore, this honyaki material was finely ground in a 7-noise mortar to make a superconductor material, and this material 109 was used as a charging agent to obtain 40% iodine.
Acetone (contains 0.3% water) 20O with added va9
The Al plate was suspended under ultrasonic irradiation in ug as cathode, p
With the T plate as the anode, 600μ for 1 minute? 1! I understand.

The obtained superconductor has a Tc of 713 and a Jc of 670^.
/cIII2.

Example 2 When electrolysis was carried out using the vinylidene chloride sheet subjected to electroless plating as the cathode in Example 1, Tc was 76 and Jc was 680^/c1112.

Example 3 When the superconductor prepared in Example 1 was fired at 500°C for 2 hours, Tc was 78 and Jc was 7108/c +a
"Met.

Example 4 1] i20. ．． 5rCOi, CaC0, and CuO in molar ratio Bi:Sr:Ca:Cu=1,5:1:
Mix at a ratio of 1:2 and heat at 900° with oxygen.
After firing for 12 hours at C and 4 hours at SO'C, it was cooled and subjected to Xm diffraction.

The X-ray diffraction pattern of this honyaki material shows B
The diffraction pattern matched that of the i+,5SrCnCu20x superconductor.

Next, after finely pulverizing this honyaki material in an agate mortar, the material was mixed with 20 Ome of acetone (containing 0.3% moisture) containing 129 mg of iodine as a charging agent, 37 mg of iodine as a charging agent, and 19 mg of nitrocellulose as a dispersing agent. They were suspended under ultrasonic irradiation and electrolyzed at 700V for 1 minute using the Δg plate as the cathode and the PT plate as the anode. Thereafter, the cathode was taken out and heated to 500° C. with a laser beam. The Tc of this superconductor is 67, J
e was 6808/e162.

(Effects of the Invention) As described above, according to the present invention, a [1i-Sr-Ca-Cu-0 based oxide conductor can be created without post-baking after electrodeposition. The electrode does not need to be heat resistant to withstand the temperature and reactivity during firing. Therefore, it is possible to use plastics, glass, low-melting materials, α-ceramics (all of which need to be imparted with conductivity by plating or mixing conductive materials), and various metals that could not be used conventionally.

In addition, if plastic or metal can be used for the substrate, it becomes easier to process the superconductor after electrodeposition, so there is no need to process the substrate in advance, and it is possible to keep it in stock as a raw material. , it is possible to quickly respond to various demands, and the application can also be expanded to inexpensive applications that previously had cost problems, such as electromagnetic shielding materials.

Furthermore, since superconductors can be created simply by electrodeposition, superconducting wires can be secretly created by using wires as electrodes and coating the surface with plating after electrodeposition.

Claims (1)

[Claims] After firing the superconductor raw material, it is crushed and dispersed in a solvent, and then electrodeposited on an electrode by electrophoresis to form B.
A method for producing a superconductor, which comprises producing an i-Sr-Ca-Cu-O based oxide superconductor.