KR920001918B1 - METHOD OF MANUFACTURING YBa2Cu3Ox SUPERCONDUCTOR THIN FILM WITH USING FLAZA - Google Patents

Abstract

The method for producing a superconductive thin film is characterized by (a) crushing the mixture of Y2O3, BaCO3 and CuO, (b) drying and calcining it to obtain a raw powder, (c) plasma spraying the raw powder on the substrate under the condition of 80 cfh Ar and 30 cfh He flow rate, 500A 45V electric power, 30-45 g/ min powder-feeding velocity and 50-100 mm distance of the torch and the substrate, (d) heat-treating the coated layer under the oxygen gas atmos. at 950 deg.C for 1 hr, and (e) furnace-cooling it at 400-500 deg.C, and air-cooling it.

Description

Manufacturing Method of YBa2Cu3OX Superconducting Thin Film by Plasma Spraying

1 is a voltage drop according to the temperature of the superconducting thin film manufactured by the present invention.

The present invention relates to a method for producing a superconducting thin film which is prepared by thermally spraying a plasma of thermally mixed mixed powder of Y ₂ O ₃ , BaCO ₃ , CuO on a stainless steel substrate.

High-temperature ceramic superconductors are superconducting materials that were previously possible at cryogenic temperatures of 4K by Professor Chu of the University of Houston in 1987, inventing a superconductor with a critical temperature of 92K in the Y-Ba-Cu-O system (also known as 1-2-3 system). Exceeded the liquid nitrogen temperature (77K).

The high-temperature superconductors developed so far are La-ba-Cu-O system of the first generation Tc 30K level and Y-Ba-Cu-O system near the second generation 90K and critical temperature depending on the apparent chemical composition and critical temperature. It can be classified as Bi-St-Ca-Cu-O system of over 100K. The ceramic superconductor can be easily manufactured by the general method of manufacturing a sintered body, so the basic physical property research in this field is progressing without any difficulties, but for the actual application of the industrial field, development of the production technology of the wire rod or the thin film is desired. On the other hand, wire rods and superconducting materials in the form of thin films have their own application fields. However, in view of overcoming mechanical brittleness, which is a basic characteristic of ceramics, the research and development of thin film type manufacturing methods should be conducted first. The method of manufacturing 1-2-3 ceramic superconducting thin film using plasma spraying has no limitation on the shape of the sprayed object, and the coating layer can be obtained in a short time, and can be applied to coating non-conductive, high melting point materials such as ceramics. Is superior to other methods. Hereinafter, the gist of the present invention will be described in detail with reference to examples of the manufacturing process as follows. The production of superconducting thin film of 1-2-3 system using plasma spraying can be roughly divided into two processes: preparation of thermal spray substrate and preparation of thermal spray powder and thermal spraying process.

Preparation of Raw Powder

Wy mixed with zirconia (WrO2) port and ball for 24 hours using Y ₂ O ₂ , VaCO ₃ and CuO with a purity ratio of 99.9% or higher and weighed with an accuracy of ± 0.01g to be 15.13%, 52.89% and 31.98%, respectively. To crush. The wet pulverized powder is dried in a dryer, 20g each in an alumina (Al2O3) crucible, calcined for 24 hours at 950 ° C standard, separated by alumina induction and mortar, and passed through 100mesh and does not pass through 230mesh. Take powder (68-168um) and use it as raw powder for thermal spraying.

Preparation of the board

The material of the board is AISI 304 stainless steel, and the surface of the board is blasted by using steel grits at 5 bar of air pressure for the purpose of improving adhesion. The substrate is further immersed in acetone and degreased with an ultrasonic cleaner.

Warrior

Plasma spraying is carried out in two stages of bond coating and 1-2-3 spraying to improve adhesion.The spraying conditions are the plasma gas flow rate of Ar and He of 80 and 30cfh, and the power to 500A and 45V. The feeding speed and distance between torch and board should be 30 ~ 45g / min and 5 ~ 100mm respectively.

Post heat treatment

The coating layer obtained from the thermal spraying is heat-treated in oxygen at 950 ° C. for 1 hour, and then cooled to 400-500 ° C., followed by air cooling thereafter. The critical temperature of the coating layer in 1-2-3 obtained at this time was 83K as shown in FIG. The ceramic superconducting thin film manufactured by the method of the present invention has no limitation on the shape of the workpiece and can be obtained in a short time, and is an excellent manufacturing method that can be applied to coating non-conductive, high melting point materials such as ceramics. There is an effect that can be widely distributed in the industry.

Claims (1)

Y ₂ O ₂ , VaCO ₃ , CuO mixing, pulverization, and drying. Plasma spraying the pulverized raw powder onto the substrate, the spraying conditions are plasma gas flow rate of Ar and He of 80, 30cfh and power of 500A, The powder feeding rate and the distance between the torch and the substrate were set at 30 to 45 g / min and 50 to 100 mm, respectively, at 45 V. The coating layer obtained from this spray was heat-treated in oxygen at 950 ° C. for 1 hour and then cooled to 400 to 500 ° C. for air cooling. Method for producing a YBa ₂ Cu ₃ O _X superconducting thin film using a plasma spray.

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