JP2003060247A - Method of manufacturing high temperature superconducting pickup coil - Google Patents

Abstract

[PROBLEMS] To obtain a high-quality high-temperature superconducting pickup coil without causing interdiffusion between atoms constituting a base and atoms constituting superconductor fine particles even at a high heat treatment temperature. To provide a method for manufacturing a high-temperature superconducting pickup coil which enables the above. SOLUTION: A step of arranging a conductive tape or a conductive wire in a coil shape on a surface of a cylindrical ceramic base material, and forming a high-temperature superconductor and / or a high-temperature superconductor precursor on the conductive tape or the conductive wire A step of electrophoretically depositing or electrodepositing a substance; and a step of heat-treating the cylindrical ceramic substrate to sinter the fine particles to form a pickup coil.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of manufacturing a high temperature superconducting pickup coil.

[0002]

2. Description of the Related Art Quantum interference type (hereinafter referred to as SQUID)
A magnetometer is a high-sensitivity magnetic sensor that can detect a magnetic field that is one-fifth or less of the earth's magnetism. Utilizing the quantization phenomenon of superconductivity, it has a high sensitivity of three digits or more compared to the conventional magnetic sensor. In particular, the development of the SQUID magnetometer using a high-temperature superconducting thin film has made it possible to operate at liquid nitrogen temperature (77.3K), and its application field is expanding.

[0003]

In the SQUID magnetometer using the conventional high temperature superconducting thin film as described above, there is a problem that it is very difficult to manufacture the pickup coil. That is, since a high temperature superconducting material cannot be formed into a three-dimensional shape because it is difficult to mold and process, it is usually manufactured as a flat plate pickup coil integrally with a SQUID element which is a thin film device. It was
However, since the flat-plate pickup coil cannot detect the gradient of the magnetic field in the z-axis direction with respect to the plane, conventionally, two or four high-temperature superconducting SQUIDs are used.
The element was used to measure the gradient of the magnetic field in the z-axis direction by detecting the difference.

That is, when two SQUID elements are used, one detection coil and one z-axis compensating coil are used, and when four SQUID elements are used, one detection coil is used. One compensation coil in the z-axis direction and two compensation coils in the x-axis direction and the y-axis direction for canceling the tilt component are used.

As described above, the conventional SQUID magnetometer using the high-temperature superconducting thin film is expensive because it requires a plurality of SQUID elements, and the characteristics of a plurality of SQUID elements are matched with each other. The SQUID element had to be adjusted or an element with similar characteristics had to be selected, which required labor and cost.

Therefore, there is a strong demand for the production of a non-planar pickup coil using a high temperature superconducting material, but a non-planar pickup coil using a high temperature superconducting material has not been produced so far.

On the other hand, the inventors of the present invention first prepared a wiring pattern on a cylindrical ceramic substrate by vacuum deposition or silver lacquer, and electrophoretic electrodeposition or electrodeposition of fine particles of a high temperature superconductor on the wiring pattern. We have proposed a method for manufacturing a high temperature superconducting pickup coil by attaching the above.

However, when a superconducting film is formed on a relatively inexpensive ceramic substrate such as an alumina substrate or a quartz glass tube by the electrophoretic deposition method, the superconducting fine particles are coated by the electrophoretic deposition and then heat-treated. In addition, there is a problem in that the atoms forming the substrate and the atoms forming the superconductor particles are interdiffused, which deteriorates the superconducting properties of the superconducting film.

In order to prevent the deterioration of the superconducting property of the superconducting film due to such mutual diffusion, 880 to 92 in an oxygen flow is used.
It is possible to perform the heat treatment at a relatively low temperature of 0 ° C. for 1 hour, but at such a low heat treatment temperature, since the growth temperature is low, the bondability between the superconducting particles is low, and the operation of the obtained pickup coil is low. The temperature is well separated from the bulk superconducting transition temperature.

Moreover, even at a low heat treatment temperature of 880 to 920 ° C., mutual diffusion of atoms forming the substrate and atoms forming the superconductor fine particles occurs.

As a method of preventing such mutual diffusion, the present inventors have previously mentioned that a buffer layer (diffusion prevention layer) is provided between them.
Was proposed, and mutual diffusion could be prevented to some extent by this method, but in this case, another problem of peeling of the buffer layer occurs.

The present invention has been made under these circumstances,
A high-temperature superconducting pickup that makes it possible to obtain a high-quality high-temperature superconducting pickup coil without mutual diffusion between the atoms constituting the substrate and the atoms constituting the superconductor particles even at a high heat treatment temperature. It is an object to provide a method for manufacturing a coil.

[0013]

In order to solve the above problems, the present invention provides a step of arranging a conductive tape or a conductive wire on the surface of a cylindrical ceramic substrate in a coil shape, the conductive tape or the conductive tape. A step of electrophoretic deposition or electrodeposition of a high-temperature superconductor and / or a high-temperature superconductor precursor on a wire, and heat treatment of the cylindrical ceramic substrate to sinter the fine particles to form a pickup coil. The present invention provides a method for manufacturing a high temperature superconducting pickup coil, which comprises the step of:

In the above-described method of manufacturing the high temperature superconducting pickup coil of the present invention, the conductive tape or the conductive wire may contain silver as a main component.
For example, it can be a silver tape or a silver wire.

The conductive tape has a width of 0.5 to 1 mm and a width of 0.
The conductive wire has a thickness of 05-0.1 mm and is 0.1-0.1 mm.
It is preferable that the wire has a wire diameter of 0.5 mm.

According to the method of manufacturing a high temperature superconducting pickup coil of the present invention having the above-described structure, it is possible to effectively prevent mutual diffusion between the atoms constituting the substrate and the atoms constituting the superconductor fine particles. Since it is possible to heat-treat at high temperature, the bonding property between superconducting particles is high,
It is possible to bring the operating temperature of the pickup coil closer to the bulk superconducting transition temperature. As a result, a high quality high temperature superconducting pickup coil can be obtained.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. In the present invention, a conductive tape or a conductive wire is arranged in a coil on the surface of a cylindrical ceramic substrate, and a high temperature superconductor and / or a high temperature superconductor precursor is electrophoretically deposited or electrodeposited thereon, Then, a heat treatment is performed.

Since the ceramic base material on which the superconducting wiring is formed used in the present invention is subjected to heat treatment,
It is desirable to satisfy the conditions that it has heat resistance up to about 000 ° C., that it is stable to superconductors, and that it is relatively close to the coefficient of thermal expansion of superconductors.
(Al ₂ O ₃ ), magnesium oxide (MgO), yttrium-stabilized zirconia (YSZ), or the like can be used. Among these, alumina can be preferably used from the viewpoint of availability.

As described above, the conductive tape or conductive wire arranged in a coil shape on the outer surface of the cylindrical ceramic substrate is one containing silver as a main component, for example, silver tape or silver wire. The conductive tape is 0.5
It is preferable that the conductive wire has a width of ˜1 mm and a thickness of 0.05 to 0.1 mm, and the conductive wire has a wire diameter of 0.1 to 0.5 mm.

That is, a width of 0.5 to 1 mm and a width of 0.05 to
Silver tape with a thickness of 0.1 mm, or 0.1
A silver wire having a wire diameter of 0.5 mm can be preferably used.

To arrange the conductive tape or the conductive wire in a coil shape on the outer surface of the cylindrical ceramic substrate, for example, simply wind the conductive tape or the conductive wire around the outer surface of the cylindrical ceramic substrate. Good. However, in order to fix the conductive tape or the conductive wire on the outer surface of the cylindrical ceramic substrate without moving, it may be fixed to the outer surface of the cylindrical ceramic substrate by an adhesive or the like.

High temperature superconductor and / or used in the present invention
Alternatively, the high temperature superconductor precursor is not particularly limited.
But, for example, YBa_TwoCu_ThreeO₇Particles, YBa_TwoCu
_FourO ₈Particles or the like can be used.

Note that electrophoretic deposition is typically used to deposit high temperature superconductors, and electrodeposition is used to deposit high temperature superconductor precursors.

In electrophoretic deposition, a substrate is placed in a solvent in which high temperature superconducting fine particles are dispersed, an anode is placed facing a conductive tape or a conductive wire, and the conductive tape or the conductive wire is used as a cathode. It is performed by applying a voltage between the electrodes. As the solvent, toluene, acetone or the like can be used. The concentration of the fine particles in the solvent is usually 30mg~40mg / cm ^3, the concentration of iodine is 0.4 mg / cm ^3.

The conditions for electrophoretic deposition can be those normally used. For example, the voltage is 40 to 500 V and the time is 10 to 60 seconds.

It is desirable that the electrophoretic deposition be performed with a magnetic field applied parallel to the electrophoretic direction. Since the base material has a cylindrical shape, in order to apply a magnetic field parallel to the migration direction, the cylindrical base material is placed in the solution at a level close to the liquid surface, and The cylindrical base material may be rotated around its axis. The magnetic field is 1
About T to 10T is desirable.

In electrodeposition, a cylindrical base material is placed in a solution for precipitating a high temperature superconductor precursor by electrolysis, an anode is placed facing a conductive tape or a conductive wire, and the conductive tape or conductive tape is used. Conductive wire is used as a cathode and a voltage is applied between the electrodes. As the solution, for example, dimethyl sulfoxide (DMSO) is used as a solvent, and a solution in which nitrates of elements constituting the high temperature superconductor precursor are dissolved can be used.

For example, 40 mmol of Y (NO_Three) ・ 6H
_TwoO, 72 mmol of Ba (NO_Three) _Two, 88 mmol C
u (NO_Three)_Three・ 6H_Two100 ml of dimethicine O
It is possible to use a solution dissolved in le sulfo oxide.
come.

The conditions for electrodeposition may be those normally used. For example, with respect to the reference electrode, the voltage −
It is 2.5 to -4V and the time is 3 to 5 minutes.

The electrophoretically electrodeposited or electrodeposited high temperature superconductor and / or high temperature superconductor precursor is then heat treated and sintered. By this heat treatment, the high temperature superconductor precursor fine particles become high temperature superconductive fine particles. Heat treatment temperature is 8
It is preferable that the temperature is 80 ° C. or higher and the melting point of the material forming the conductive tape or the conductive wire is lower than 962 ° C. in the case of silver, and the heat treatment atmosphere is oxygen.

A method of manufacturing a high temperature superconducting pickup coil according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a high temperature superconducting pickup coil manufactured by a method according to an embodiment of the present invention.

First, it consists of alumina with a purity of 97%.
A cylindrical ceramic substrate 1 having an inner diameter of 18 mm and an outer diameter of 21 mm and having a semi-spherical closed tip was prepared. The outer surface of the cylindrical ceramic substrate 1 has a width of 0.5 mm and a thickness of 0.1.
A 3 mm silver tape (manufactured by Tanaka Kikinzoku Co., Ltd.) was wound around the tip, the center and the lower part in a coil shape, and arranged so as to be connected to each other on the inner surface of the cylindrical ceramic substrate 1.

Then, high temperature superconducting fine particles or electrophoretic particles were electrophoretically deposited on the silver tape on the inner and outer surfaces. As the high-temperature superconducting fine particles, YBa2Cu3O7 particles having a particle diameter of 3 μm or less were used in this example. Electrophoretic electrodeposition was performed as follows.

That is, the cylindrical ceramic substrate 1 was placed in an electrodeposition bath containing 500 ml of acetone, 200 ml of iodine, and 715 g of YBa2Cu3O7.
As the anode, a spiral platinum wire (0.5 mm diameter) was placed outside the cylindrical ceramic substrate 1, and a linear platinum wire (0.5 mm diameter) was placed inside. As the cathode, a silver tape arranged on the inner surface and outer surface of the cylindrical ceramic substrate 1 was used.

A voltage of 500 V is applied between the anode and the cathode for 20 times.
By applying for 2 seconds, high-temperature superconducting fine particles were electrophoretically deposited on the silver tape formed on the inner surface and outer surface of the cylindrical ceramic substrate 1.

Then, the cylindrical ceramic substrate 1 was subjected to the following heat history. That is, the temperature was first raised to 300 ° C. and maintained for 1 hour, and then the temperature was raised to 500 ° C./h for 8 hours.
The temperature is raised to 00 ° C, and then the temperature is raised to 100 ° C / h for 93
The temperature was raised to 0 ° C. and maintained there for 20 hours. The temperature was first lowered to 500 ° C. at a rate of 60 ° C./h, maintained there for 5 hours, and then cooled to room temperature at a rate of 60 ° C./h.

As a result, as shown in FIG. 1, the input coil wiring 2 was formed on the surface of the cylindrical ceramic substrate 1, and the high temperature superconducting pickup coil according to this example was obtained. In the figure, the broken line indicates the wiring formed on the inner surface of the cylindrical ceramic substrate 1.

As described above, the high temperature superconducting pickup coil could be manufactured with high precision and at low cost by a simple process.

In the embodiments described above, the silver tape is wound around the cylindrical ceramic substrate and arranged. However, the present invention is not limited to this, and a silver wire may be used instead of the silver tape.

Further, in the above embodiment, the example in which the high temperature superconducting fine particles were electrophoretically deposited was shown, but the present invention is not limited to this, and the high temperature superconducting fine particles can be electrodeposited. Also,
Instead of the high temperature superconducting fine particles, high temperature superconducting precursor fine particles, which become high temperature superconducting fine particles by heat treatment, may be electrophoretically deposited. Alternatively, a mixture of high temperature superconducting fine particles and high temperature superconducting precursor fine particles can be electrophoretically deposited or electrodeposited.

[0041]

As described above in detail, according to the present invention, the conductive tape or the conductive wire is arranged in the form of a coil on the surface of the cylindrical ceramic substrate, and the high temperature superconductor and / or the high temperature superconductor is placed there. Since the high-temperature superconductor precursor is electrophoretically electrodeposited or electrodeposited, mutual diffusion between atoms forming the substrate and atoms forming the superconductor fine particles does not occur,
Since the heat treatment can be performed at a high temperature, the bond between the superconducting particles is high, and the operating temperature of the pickup coil can be brought closer to the bulk superconducting transition temperature.
As a result, a high quality high temperature superconducting pickup coil can be obtained at low cost.

Since the pickup coil can be easily scaled up, the sensitivity can be easily improved.

The high-temperature superconducting pickup coil manufactured by the method of the present invention is inexpensive and has high performance and low cost, so that it is expected to be widely used and contributes to the technical field of the superconducting quantum interferometer. The degree is very high.

[Brief description of drawings]

FIG. 1 is a perspective view showing a high temperature superconducting pickup coil manufactured by a method according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Cylindrical ceramic substrate 2 ... Pickup coil wiring

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Claims (3)

[Claims] 1. A step of arranging a conductive tape or a conductive wire in a coil shape on the surface of a cylindrical ceramic substrate, a high temperature superconductor and / or a high temperature superconductor on the conductive tape or the conductive wire. A high temperature superconducting pickup coil, comprising: a step of electrophoretically depositing or electrodepositing a precursor; and a step of heat-treating the cylindrical ceramic substrate to sinter the fine particles to form a pickup coil. Manufacturing method. 2. The method for manufacturing a high temperature superconducting pickup coil according to claim 1, wherein the conductive tape or the conductive wire contains silver as a main component. 3. The conductive tape has a width of 0.5 to 1 mm and a thickness of 0.05 to 0.1 mm, and the conductive wire has a wire diameter of 0.1 to 0.5 mm. The method for manufacturing a high-temperature superconducting pickup coil according to claim 1 or 2, characterized in that: