JPH01249608A - Production of superconductor - Google Patents

Abstract

PURPOSE:To obtain a dence superconductor having high adhesion to a substrate and high superconducting characteristic, etc., by forming liquid drops of a starting material prepd. by irradiating with laser beams while feeding a metallic starting material to a nozzle section of a thermal spraying cylinder, ejecting the liquid drops onto the substrate with carrier gas and forming a film of a precursor of the superconductor, and heat-treating the formed film. CONSTITUTION:A thermal spraying cylinder 2 is constructed by forming a nozzle section 3 at an end and a condenser lens 4 for laser beam an another end. A feeding port 7 of protective gas for the lens is formed on a side wall of the thermal spraying cylinder 2, and a hood 8 for feeding carrier gas is provided to the periphery of the nozzle section 3. Liquid drops of the starting material are formed by irradiating a metallic starting material while feeding the material to the nozzle section 3 from a feeding device 5 of the metallic starting material installed to an end of the nozzle section 3. At the same time, the liquid drops of the starting material are ejected onto the substrate 9 with the carrier gas from the feeding hood 8. To obtain a compound body 11 by forming film of a precursor 10 of the superconductor. The superconductor is obtd. by heat-treating the compound body 11, thereafter.

Description

[Detailed Description of the Invention] [II: Field of Application for Business Owners] The present invention relates to a method for manufacturing a superconductor that can be used as a superconducting device such as a Noyosefson element or a superconducting memory element, or a coil for a superconducting magnet.

[Prior art] In recent years, critical/! transition from superconducting state to superconducting state. !
Various oxide-based superconducting materials that exhibit temperatures higher than liquid nitrogen temperatures are being discovered. This type of oxide-based superconductor can be used under much better cooling conditions than conventional alloy-based or intermetallic compound thread LA conductors, which require cooling with liquid helium. Since then, various research and development efforts have been carried out as superconductors that are extremely promising for practical use.

By the way, the critical phase in such oxide-based superconductors
l”/2.L degree and critical current density vary greatly depending on various factors such as manufacturing method, manufacturing conditions, etc. 4°
Ruji is known. At present, it is known that materials manufactured using vacuum thin film manufacturing techniques such as sputtering method exhibit relatively good superconductivity. However, since the method for manufacturing superconductors using this thin film manufacturing technology is carried out in a vacuum, it is difficult to manufacture them using simple equipment, and at the same time, the substrate on which the superconductors are formed is There are restrictions on the size and material of the superconductor, and it takes a long time to obtain a superconductor with a sufficient thickness. On the other hand, among metal spraying methods, plasma spraying, which uses heated oil and plasma, has the advantage of being able to produce oxide-based superconductors with sufficient film thickness in a single time without the need for vacuum equipment. . In this plasma spraying method, metal raw material powder consisting of the constituent elements of the oxide-based superconductor is heated with a plasma torch, reacted with oxygen in the air, and then sprayed and deposited on a base material using a carrier gas. An oxide-based superconductor conductor is obtained by subjecting the base material to heat treatment.

[Problem to be solved by the invention] However, oxide superconductors formed by plasma spraying are porous because they are deposits of atomic metal raw material powder reacted with atmospheric oxygen. Afterwards, the sintering process is performed to improve the porosity.1. There are limits to superconducting properties such as critical field tAE density, and Ji
+, poor adhesion with '44, 1'J mechanical strength or low. Furthermore, since it is difficult to control the scattering of the superheated metal raw material powder and the reaction with atmospheric oxygen, it is difficult to control the formation of the formed pattern, and it is difficult to control the formation of oxides with a desired composition ratio and excellent superconducting properties. There was a problem that a superconductor could not be obtained.

This invention was made in order to solve the above-mentioned problems, and provides a method for manufacturing a superconductor having a dense crystal structure with a well-controlled composition ratio and excellent adhesion to a base material in a large amount of time. is intended to provide.

[Tanu's Means for Solving the Problems] This invention comprises a thermal spraying tube with a nozzle section at one end and a laser beam condensing lens at the other end, and a lens protective gas supply port on the side wall of the thermal spraying tube. A superconductor is manufactured using a laser beam thermal spraying apparatus provided with a metal raw material supply device for supplying metal raw materials to the tip of the nozzle part. The method comprises supplying a metal raw material to a nozzle part, irradiating the material with a laser beam to form raw material melt droplets, and ejecting the raw material melt droplets from a carrier gas supply hood onto a base material provided opposite to the nozzle part. The solution was to form a superconducting precursor film by blowing out a carrier gas, form a composite, and then heat-treat the composite.

[Operation] A metal raw material consisting of the constituent elements of a superconductor is supplied to the nozzle part, irradiated with a laser beam and melted to form raw material molten droplets, and then the raw material molten droplets are transported by a carrier gas discharged from a carrier gas supply hood. A superconducting precursor film is formed on the base material by ejecting the superconducting precursor film. This superconducting fi? Since the precursor film is formed by ejecting raw material melt droplets, it is dense and has good adhesion to the base material. Furthermore, since the composite formed by forming a high-density superconducting precursor film on a base material is heat-treated to form a superconductor, a high-density superconductor can be obtained.

The present invention will be described in detail below.

FIG. 1 shows an example of a laser beam thermal spraying apparatus suitably used in the superconductor manufacturing method of the present invention.

This laser beam spraying device i! 21 forms a nozzle part 3 with one end converging and a laser beam condensing lens 4 attached to the other end, and a backflow prevention hood 6 and a lens protective gas supply lower. A carrier gas supply hood 8 is attached to the outer periphery of the nozzle part 3, and a base material 9 is arranged to face the thermal spray tube 2 at right angles to the nozzle part 3 at a constant distance.

Further, a supply section 5a connected to the raw material supply device 15 is provided on the side of the nozzle section 3, and the tip of the supply section 5a is close to the tip opening of the nozzle section 3.

The metal raw material supply device 5 is a device for supplying metal raw materials consisting of constituent elements of a superconductor directly below the nozzle section 3, and feeds metal raw materials in various shadow shapes from the supply section 5a at a constant speed. It has become.

For example, when the metal raw material consists of a tape body or a wire-shaped wire rod, a J-float wire feeder is preferably used as the metal raw material supply device 5, and when the metal raw material is a powder, the metal raw material supply device 5 is preferably used. A powder feeder that delivers a high pressure inert Y1 gas such as inert argon gas is preferably used.

The metal raw material connected to this metal raw material supply device 5 (metal raw material supplied to the nozzle part 3 by the supply part 58 has the general formula A-1
1-Cu-0 (where Δ is Y, Sc, I-a.

Periodic table III of Yb, Er, Eu, tlo, Dy, etc.
Periodic table V b such as "1 insert of group a element" - or B1
Indicates one or more elements of group Ill h of the periodic table such as group element or 1 ゛l, B is +3e, Mg, Ca, S r, B
Indicates one or more elements of group na of the periodic table, such as a. ) When manufacturing an oxide-based superconductor represented by A-
It is also possible to use either a B-Cu alloy or a copper alloy. In addition, the manufacturing of intermetallic superconductors such as N bss n, V sG I&, etc. is similar to the manufacturing of oxide-based superconductors. be. Furthermore, there is no limit to the shape of the metal nl material, and in addition to tape bodies, wire materials, etc.
Powder or the like can be used. In particular, when a metal raw material made of a wire material such as a tape body or a wire material is used, it is easy to adjust the composition ratio and supply the superconducting precursor film IO formed on the base material 9.

A laser beam condensing lens 4 provided at the other end of the thermal spray tube 2
The laser beam oscillated by a laser oscillation device (not shown) is focused at a high energy density by the nozzle part 3 at the lower end of the thermal spray tube 2, and the metal raw material supplied from the metal raw material supply device 5 is melted. It belongs to Nu.

The thermal spray tube 2 is provided with a lens protective gas supply lower and a backflow prevention hood 6 in this order from the side where the laser beam condensing lens 4 is disposed. This lens protective gas supply lower supplies lens protective gas for protecting the laser beam condensing lens 4 into the thermal spray tube 2, and is connected to a gas supply device such as a gas cylinder (not shown). An inert gas such as argon gas can be used as this lens protective gas, and by supplying it along the shape of the backflow prevention hood 6 toward the nozzle part 3 while causing convection, it is heated by laser beam irradiation. Laser beam condensing lens 4
to cool down. The backflow prevention hood 6 consists of a hood that first becomes constricted toward the nozzle section 3, so that the lens protective gas is quickly discharged from the nozzle section 3 by υ1 so that the lens protective gas can sufficiently cool the laser beam condensing lens 4. It is something.

Furthermore, the nozzle part 3 was formed by thermal spraying f? outside of i2+,
', 1 part is connected to a pressure gas supply device (not shown) which receives carrier gas (carrier gas 9-supply hood 8 (=11), not shown). This carrier gas supply hood 8 consists of a hollow truncated conical body concentric with the nozzle part 3, and is disposed 5 to cover the nozzle part 3. A high-pressure inert gas such as argon gas or nitrogen is used.This high-pressure carrier gas transports the raw material melt droplets to the nozzle
] 1 (was spouted onto the material 9 and the second
As shown in the figure, a superconducting precursor film 10 is formed to form a composite 11.

Furthermore, a 1-line moving device (not shown) is attached to the base material 9 or the thermal spraying tube 2, and the size of the base material 9 can be adjusted while keeping the distance between the base material 9 and the thermal spraying tube 2 constant. The base material 9 or the thermal spray tube 2 can be moved in parallel depending on the thickness of the body membrane 10. In this way, even if the base material 9 is made of a long tape, a wire, or a large-area plate, a uniform film 1j7 is continuously formed on the base material 9. It is possible to form a superconducting precursor film lO of

The base material 9 is made of stainless steel, silver, copper, titanium, nickel, zirconium, Cu-Ni alloy, etc. with a melting point of 800°C.
Plates, wires, tapes, rods, etc. made of the above metals, alloys, ceramics such as alumina, quartz, etc. can be used.

In the manufacturing method of the invention, first, using the laser beam spraying apparatus as described above, 7, r,
After a composite 11 is formed by forming a superconducting precursor I210 on +49, this composite 11 is heat-treated to become a superconductor. This trajectory treatment condition (depending on the superconductor manufactured) may be selected as appropriate, or generally 'l-13
When creating an a-Cu~0-based oxide superconductor, the superconducting precursor film 10 is sintered into a U oxide by heating at 800 to 1100°C for 6 to 100 hours in an oxygen atmosphere. , 400 to 600° C. for a certain period of time to promote transformation of the crystal structure of the produced oxide superconductor into an orthorhombic crystal structure. Naori 1-
800~ for 3r-Ca-Cu-0 type superconductors
Heat treatment conditions such as heating to 900° C. and then rapidly cooling may be used. In addition, when creating an intermetallic compound-based superconductor, the
In order to create an alloy superconductor for 800 hours, heat treatment conditions of 300 to 500° C. and 1 to 100 hours in vacuum or an inert gas atmosphere are suitable.

According to such a manufacturing method, the metal raw material is melted by a laser beam in the nozzle section 3. At this time, 421 Yorohara 1
1 (J-uni 1 process using plasma melting method:
Since the superconducting precursor film 1o(') formed on M 449 J. has a high density and has excellent adhesion to the base material 9. Since the composite II on which the precursor film 10 is formed is heat-treated to become a superconductor, the obtained superconductor becomes a highly dense material, exhibits good superconducting properties, and has excellent mechanical strength, making it suitable for practical use. In addition, the supply section 5a of the metal raw material supply device 5 is arranged so that the metal raw material can be supplied to the tip of the nozzle section 3.
This prevents raw material molten droplets from clogging the nozzle part 3 or flowing back inside the thermal spray tube 2, and
Since the superconducting precursor film IO can be formed on the base material 9 without changing the composition of the metal raw material from when it was supplied, a superconductor having a desired composition ratio can be manufactured. Further, by increasing the supply rate of the metal raw material and the irradiation power of the laser beam, the amount of raw material melt droplets ejected can be increased, so that a superconducting precursor film 10 with a large thickness can be easily obtained.

Furthermore, as is typical of the thermal spray tube 2, the base materials 9 can be moved parallel to each other while maintaining a constant interval, so there is no restriction on the length or size of the base materials 9, and it can be used for large-area plates, long wire rods, and tapes. A superconductor can also be easily formed on the base material 9 made of a solid body. Furthermore, unlike manufacturing methods using vacuum thin film manufacturing techniques such as sputtering, the manufacturing method of the present invention does not require any special vacuum equipment, so superconductors can be easily obtained.

Note that the composition of the superconducting precursor 11i10 formed on the base material 9 can be changed as appropriate depending on the method of supplying the metal raw material. For example, when a wire material made of an alloy of constituent elements of a superconductor is used as a metal raw material, the wire material made of each alloy component metal is sequentially supplied and thermal sprayed to form a superconductor on the base material 9. Precursor film 10
The composition ratio can be changed continuously from the base material 9 side.

For example, a copper plate is used as the base material 9, and Y-Ba is placed on top of this.
-When forming a superconducting precursor film IO consisting of Cu, Y
By using a wire material made of -Ba-Cu alloy and a -12= copper wire material, and sequentially changing the supply rate of the copper wire material, the concentration of the copper component in the superconducting precursor film 10 to be formed can be changed. Can you super? LL-conducting precursor l
The coefficient of thermal expansion of O can be changed sequentially from the base material 9 side. In this way, it is possible to prevent cracking defects caused by the difference in coefficient of thermal expansion between the base material 9 and the superconducting precursor [10] when the composite body 11 is subjected to the island treatment.

Furthermore, when creating an intermetallic compound-based superconductor and an alloy-based superconductor, as shown in FIG. Composite I formed by sequentially laminating layers with film thicknesses corresponding to
I, and heat-treating this composite 11 to thermally diffuse the elements of each superconducting precursor film lOa, tab, to produce an intermetallic compound-based or alloy-based superconductor.

When forming such single-phase superconducting precursor films 10a and 1Ob on the base material 9, the superconductor @ 10 m that is in direct contact with the base material 9 contains a material that is difficult to diffuse into the base material 9. It is preferable to use In other words, 7-1 is exemplified by -2°
If so, a copper group ((N b to 9L: + S n to f
5 intermetallic compounds? 1 [j [5] When the superconducting body 10a is in direct contact with the base material 9, niobium, which is less likely to diffuse into copper during heat treatment, is used, and the molar ratio of niobium and tin in the superconductor is It is preferable that the film thickness of the superconducting precursor 10a made of niobium is three times that of the film P1 of the superconducting precursor 101 made of tin so that the thickness is 3.1. In this case, if the superconducting precursor film 10a is formed of tin, tin will be diffused into the copper base material 9 during heat treatment and the base material 9 will be contaminated, which is not preferable.

In addition to supplying the metal raw material to the tip of the nozzle as shown in this example, it is also possible to supply the metal raw material into the spray tube, but in this case, the molten raw material droplets may adhere to the nozzle. This may reduce the production efficiency of the superconducting precursor film or cause clogging of the nozzle.

[Example] A Y-Ba-Cu-0 based superconductor was manufactured based on the manufacturing method of the present invention.

Composition ratio/Nail molar ratio Y:IJa:Cu-1:2:
A wire 4A made of alloy No. 3 was prepared as Metal 14; i 4'-4, and a copper plate was prepared as JA 44. The metal raw material made of this wire material is supplied to the laser beam thermal spraying device shown in Fig. 1, and Y-B with a diameter of η 100 μm is applied onto a copper base material.
A composite was created by forming a superconducting precursor film consisting of a-C(I). This composite was heat-treated at 900°C for 5 hours in an oxygen atmosphere to form a Y-Ba-Cu-0 based oxide. The oxide-based superconductor thus obtained had a density of 5.9 g/cm'', a critical temperature of 91, and a critical current density of 24,000 A/cm''. It was also confirmed that the material had excellent superconducting properties.

[Effects of the Invention] As explained above, the method for manufacturing a superconductor of the present invention involves supplying a metal raw material to a nozzle part, irradiating a laser beam to form a raw material melt droplet, and directing this raw material melt droplet to the nozzle part. A superconducting precursor film is formed on a substrate provided with a carrier gas by spraying it with carrier gas discharged from a carrier gas supply hood, and after forming a composite, this composite is subjected to specific heat treatment. Therefore, it is possible to manufacture superconductors with good adhesion to the base material, and also to have a dense structure, and especially in the case of oxide-based superconductors, a high sintered density can be obtained, and a good It exhibits superconducting properties.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a laser beam thermal spraying apparatus suitably used in the method of manufacturing a superconductor of the present invention, and FIGS. FIG. 2 shows a schematic cross-sectional view of the body. l... Laser beam spraying device, 2... Thermal spray tube, 3
... Nozzle part, 4... Laser beam focusing lens, 5... Metal raw material supply device, 6... Backflow prevention hood, 7... Lens protective gas supply port, 8... Carrier gas supply mouth, 9... base material, 10... superconductor precursor, 11...
・Complex.

Claims (1)

[Claims] A thermal spraying tube is constructed by having one end as a nozzle portion and a laser beam condensing lens provided at the other end, and a lens protection gas supply port is provided on the side wall of the thermal spraying tube, and the area around the nozzle portion is A method for producing a superconductor using a laser beam thermal spraying apparatus, which is covered with a carrier gas supply hood and is equipped with a metal raw material supply device that supplies the metal raw material to the tip of the nozzle part, the method comprising: While supplying the material, a laser beam is irradiated to form raw material melt droplets, and the raw material melt droplets are ejected onto a base material provided opposite the nozzle part using a carrier gas discharged from a carrier gas supply hood to form superconducting precursors. A method for producing a superconductor, which comprises forming a film to form a composite, and then subjecting the composite to heat treatment.