JP2624828B2 - Magnetometer and method for detecting deterioration of metal material using the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a magnetometer and a magnetic flux sensor using a superconducting quantum interferometer, and particularly to a ferrite-containing system used in a high temperature environment such as a chemical plant and a nuclear power plant. The present invention relates to a pickup coil (probe coil) and a core for a pickup coil (probe coil) suitable for detecting high-temperature aging embrittlement damage in an actual machine portion of a metal material such as stainless steel.

[Conventional technology]

Superconductivity that exhibits high critical current characteristics in a high magnetic field region used for fusion toroidal magnets, magnets for particle accelerators, magnets for superconducting generators, etc., instead of low magnetic fields as in the case of deterioration diagnosis of ferrite-containing stainless steel A method for manufacturing a sheet coil is disclosed in
There is a technique described in Japanese Patent No. 7704.

On the other hand, as a method for detecting the degree of high-temperature embrittlement damage of an actual ferrite-containing stainless steel member, there is a method described in JP-A-61-28859. This is a method of detecting the degree of embrittlement of the relevant part by magnetically measuring the change in the amount of ferrite after long-time use at a high temperature of a real machine member using a ferrite scope.

[Problems to be solved by the invention]

Japanese Patent Application Laid-Open No. 61-28859 discloses a method for measuring a change in the amount of ferrite using a ferrite scope. Therefore, a change in magnetic properties due to precipitation of an α ′ phase or a G phase caused by spinodal decomposition of an initial ferrite phase. There was a problem that can not be measured.

JP-A-62-277704, relates to a superconducting conductor such as Mb ₃ Sn superconducting intermetallic compound, a substrate containing at least one of two or more metal elements constituting the superconducting intermetallic compound, A metal plate containing the remaining metal element is stacked, and an additional member containing a third element such as Ti or Ta for improving the critical current density in a high magnetic field region is inserted between the metal plates, thereby heating a laser beam, an electron beam, or the like. This is a method of manufacturing a superconducting sheet coil by performing a circuit forming process using a beam. According to the above method, a superconducting circuit can be produced by adding a third element without alloying the substrate and the metal plate, so that a superconducting coil exhibiting excellent critical current characteristics in a high magnetic field region can be manufactured. However, the above prior art does not discuss a recent method of manufacturing a coil made of a high-temperature oxide superconducting material, and no consideration is given to a method of manufacturing an optimum superconducting printed coil in a low magnetic field.

As another prior art, there is a technique described in JP-A-62-140403. According to this, in a superconducting coil used for a bending electromagnet of an accelerator or the like, a critical current characteristic of a superconducting element wire is provided by providing a plurality of closed curved surfaces in which leads of the superconducting coil cross each other and flow currents in opposite directions. , A uniform magnetic field with little irregular magnetic field can be generated near the center of the superconducting coil. However, the above-mentioned prior art is effective in a high magnetic field such as an accelerator, but a superconducting quantum interference device (hereinafter also referred to as a skid).
In the detection of such a weak magnetic field, the influence of the external and internal noises is greater than the irregular magnetic field caused by the coil outlet.

An object of the present invention is to improve the sensitivity and signal resolution of a magnetic flux transmission circuit or a superconducting quantum interference device magnetometer provided with a magnetic flux transformer, and to use a real machine of a metal material such as ferrite-containing stainless steel used in a high-temperature environment. An object of the present invention is to provide a method and an apparatus capable of detecting the degree of embrittlement of a member with high accuracy.

[Means for solving the problem]

The above object is achieved by providing a probe coil or a pickup coil as a printed coil in a magnetic flux transformer of a superconducting quantum interference element fluxmeter, and providing the printed coil with a printed coil core of a soft magnetic material.
Achieved. The print coil may be a thin film print coil or a thin plate print coil. In addition, two or more print coils can be stacked, and if the winding direction of the two print coils is changed, it becomes a magnetic flux gradiometer. Sputtering, laser sputtering, MBE method, MOCVD method, spray pyrolysis method, etc. can be adopted as a method of manufacturing a thin film print coil. In the case of a thin film print coil, a doctor blade method is possible.

In the following description, a probe coil (flaw detection coil) is associated with a magnetic flux transmission circuit, and a pickup coil (detection coil) is associated with a magnetic flux transformer. The magnetic flux transmission circuit and the magnetic flux transformer are both superconducting closed circuits and do not need to be technically distinguished from each other. However, for convenience, terms are used in such a manner. The print coil is a coil formed in a thin film or a thin plate, and is not limited to a coil formed by printing.

(Fluxmeter) The magnetometer according to the present invention detects the degree of embrittlement of a metal material. An excitation coil for applying a magnetic field to the metal material as an object to be measured, and a probe coil or a pickup coil are measured. A magnetic flux transmission circuit or a magnetic flux transformer arranged so as to face an object; and a superconducting quantum interference device provided within a reach of a magnetic flux generated from the circuit or the transformer, and a printed coil is applied to the coil. And That is, the magnetometer of the present invention detects the degree of embrittlement of a metal material, and uses the metal material as an object to be measured, an excitation coil that applies a magnetic field thereto, and by applying this magnetic field, A superconducting quantum interference device for detecting a change in the obtained magnetic properties, and a superconducting closed circuit in which a probe coil or a pickup coil is arranged so as to face the object to be measured, wherein the superconducting quantum interference device includes the superconducting closed circuit. It is arranged within a range where the magnetic flux generated from the circuit reaches and magnetically coupled with the magnetic flux transmission circuit, and a superconducting printed coil is applied to the probe coil or the pickup coil. More preferably, a core of a soft magnetic material is used together. If a soft magnetic core is used together, the probe coil does not necessarily need to be a proto coil. It is preferable to insert a member (inclusion) that defines the distance between these members and the object to be measured.

The relationship between the coil and the core is such that the printed coil is fitted into the concave portion of the plate-shaped core having the concave portion, and the core is formed of a soft magnetic material to suppress magnetic flux leakage.

A soft magnetic material core is provided on the opposite side of the print coil from the sample to be measured.

The core of the soft magnetic material is mounted between the superconducting ribbons of the print coil, and the print coil and the core of the soft magnetic material are housed on the same plane.

The above-mentioned core and the above-mentioned core are provided as a unit.

The core between the superconducting ribbons of the printed coil is extended toward the sample to be measured and is brought into contact with the sample to be measured.

 Lay two or more print coils.

(Magnetic Shielding) The magnetic shielding is a method of covering the entire surface except for the printed coil where the magnetic flux is incident with a magnetic shielding plate, and covering a magnetic flux transmission circuit or a lead wire of a magnetic flux transformer with a magnetic shielding tube and using the magnetic shielding tube. Then, there is a method of covering the coil transmitting the magnetic flux to the skid and the skid with a magnetic shielding plate.

It is preferable that the magnetic shield plate and the magnetic shield tube are made of a high magnetic permeability material or μ metal.

(Flux Gradiometer) The magnetic flux gradiometer of the present invention is provided with a probe coil or a second printed coil, which is reversely wound with a pickup coil, provided on the opposite side of the probe coil or the pickup coil from the object to be measured. It is.

(Print Coil) It is desirable that the probe coil (also called a pickup coil) or the pickup coil (also called a probe coil) be a printed coil.

 The following is an example of a method for manufacturing a printed coil.

A mask prepared in advance according to the shape of the printed coil is placed on the substrate, and a superconducting material target disposed in front of the mold is sputtered to form a superconducting thin film coil on the substrate.

Instead of the above-mentioned sputter, electron beam evaporation, laser sputter evaporation, MBE evaporation, MOCVD evaporation, spray pyrolysis evaporation, or a combination thereof, or a combination of these and a sputter is performed.

A mixture having plasticity to be a superconductor (that is, a superconducting material) is formed into a wire by cold working, and the wire is deformed into a coil shape, and then formed into a print coil shape by a doctor blade method and fired.

The mixture (of the superconducting material) having plasticity to be a superconductor is formed into a plate by a doctor blade method, and the plate is formed into a print coil shape by a direct processing method, and then fired.

A negative image of the printed coil is formed on the surface of the substrate, and then a thin film is applied to the entire surface, and then the negative image formed product and the superconducting thin film applied thereon are removed in a negative pattern with a solvent to form a negative pattern. A superconducting thin-film coil is formed as the remainder.

A positive pattern of the print coil is formed on the superconducting thin film on the substrate surface, the negative pattern is removed by etching, and the resist forming the remaining positive pattern surface is removed by a solvent or is etched by a dry etching process.

The superconducting thin film on the substrate is sputtered or ion-implanted with a focused ion beam, and the beam is scanned.

The thin film on the substrate is irradiated with a laser beam and heated and scanned to form a negative pattern at a temperature at which a non-superconducting phase is formed and a positive pattern at a temperature at which a superconducting phase is formed.

A coil pattern is obtained by making the superconducting material into a paste and screen-printing it on a substrate.

Silk screen printing or a photosensitive resin is used for forming the negative image and the coil pattern.

 Heat treatment is performed in oxygen or air.

(Core) The core of the present invention is made of a soft magnetic material. This manufacturing method
It is characterized by removing the non-uniformity of internal stress due to point defects, lattice defects and precipitation of impurities by heat treatment, and adjusting the direction of easy magnetization by cooling in a magnetic field, rolling and recrystallization.

(Deterioration Detection Method) In the degradation detection method of the present invention, a magnetic field is applied to a metal material as an object to be measured, and a change in magnetic characteristics specific to the object to be measured is monitored. In a deterioration detection method for determining the degree of deterioration, the change in the magnetic characteristics is measured using the magnetometer according to the present invention.

[Action]

In a superconducting quantum interference device magnetic transformer (magnetic flux transfer circuit), the self-inductance of the pickup coil is generally reduced by using a printed coil composed of a superconducting ribbon for the detection coil. Furthermore, the transmission factor ε (sensitivity) of the magnetic flux of the magnetic flux transformer (magnetic flux transmission circuit) increases due to the decrease of the self-inductance, and as a result, the signal resolution of the magnetometer improves. In addition, since the print coil is provided with a soft magnetic material print coil core, magnetic flux is guided into the core, so that leakage of magnetic flux passing through the superconducting loop of the print coil is suppressed, and noise from an external magnetic field is reduced. The sensitivity as a magnetic sensor is further improved because it can be reduced. Further, the change in the magnetomotive force due to the α 'phase and the G phase precipitated in the ferrite phase of the ferrite-containing stainless steel used in a high-temperature environment can be provided in the vicinity of the measurement sample of the pickup coil. It is measured with high accuracy by a magnetic sensor (magnetometer).

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Configuration of Magnetic Sensor) FIGS. 1 and 20 to 25 are schematic configuration diagrams of a magnetic flux meter (magnetic sensor) according to an embodiment of the present invention. In the embodiment shown in FIG. 1, a superconducting quantum interferometer (skid) 1 is provided on an upper part, and a pickup coil 3 made of a printed coil is provided near a measurement sample 2.
Was placed. The superconducting quantum interferometer (skid) 1 and the pickup coil 3 are provided in a shield 99 for shielding external noise. As shown in FIG. 1, the approximate dimensions of the device are that the diameter W of the device is 20 to 200 mm and the height H of the device is 50 to 200 mm. The thickness A of the pickup coil 3 is 50 μm to 3 mm, and the pickup coil 3 and the sample 2 are placed in close contact with each other or are arranged close to each other. The distance B between the pickup coil 3 and the sample 2 is approximately 100 μ
m to 5 mm.

The pickup coil 3 can be formed by a thin film or a thin plate. FIGS. 1 and 20 to 25 show the case of a thin plate as an example. In the embodiment shown in FIG. 20, a member 5 whose relative permeability is close to 1 and suppresses magnetic flux absorption loss is inserted in order to define the distance between the pickup coil 4 and the measurement sample 2. As the material of the member 5, an organic insulating material such as polyethylene or Teflon or an inorganic insulating material is suitable. The printed coil can follow a slight change in magnetic flux of the measurement sample 2, and improves the sensitivity and signal resolution of the magnetic sensor.

In the embodiment shown in FIG. 21, a print coil core (1) 6 made of a soft magnetic material is provided on the side opposite to the measurement sample 2 with respect to the print coil 4. As soft magnetic materials, permalloy (PC) with low hysteresis loss and high hardness permalloy (HP
An iron-nickel alloy such as C), sendust, or a ferrite material resistant to high frequency is effective. By mounting the print coil core (1) 6, the leakage of magnetic flux passing through the print coil 4 is suppressed, and the signal strength of the magnetic sensor is increased. In the embodiment of FIG. 22, the print coil core (2) 7 is fitted between the superconducting ribbons of the print coil 4, and the print coil 4 and the print coil core (2) are inserted.
7 were housed on the same plane. In the embodiment of FIG. 23, a print coil core (3) 8 in which the print coil core (1) 6 of FIG. 21 and the print coil core (2) 7 of FIG. 22 are integrated is mounted. did. Further, in the embodiment of FIG. 24, the core between the superconducting ribbons of the print coil 4 of FIG. 23 is extended toward the measurement sample side, and a print coil core (4) 9 that comes into contact with the measurement sample 2 is provided. Since the magnetic field lines emitted from the measurement sample 2 are guided directly into the core by the print coil core (4) 9, the leakage magnetic flux is reduced, noise is canceled, and the sensitivity of the magnetic sensor is improved.

FIG. 25 is a schematic diagram of a magnetic flux gradient meter. It has a magnetic flux transmission circuit in which two pickup coils having the same self-inductance are connected in series, one lower pickup coil 10 is set on the measured object side, and the other upper pickup coil 11 is set on the opposite side of the measured object side. They are arranged in the opposite direction. In this case, since the uniform magnetic field cancels out, only the difference between the magnetic fluxes picked up by the two pickup coils becomes a signal transmitted to the SQVID. There are various methods for arranging the cores. For example, there is a method for arranging the cores 17 as shown in FIG. Using this flux gradient meter, it is possible to investigate the distribution of α 'phase and G phase in the ferrite phase in the depth direction, and a uniform external magnetic field is subtracted. It is convenient and advantageous in S / N.

FIG. 25 shows that the lower print coil 10 is provided in the vicinity of the measurement sample 2 with the sensitivity of the magnetic sensor, and the lower print coil and the upper print coil 11 reversely wound on the opposite side of the lower print coil 10 from the measurement sample 2. . With these two printed coils, the magnetic flux gradient can be measured.In contrast to the above-described printed coil, which measures the insulation value, the relative value can be measured and the direction of the magnetic flux can be detected. It becomes advantageous in.

Thus, the magnetometer shown in FIG. 25 is provided with two pickup coils, so that the above-described magnetometer measures absolute values, but can measure relative values and detect the direction of magnetic flux. The gradient can be measured.

FIG. 26 shows a magnetometer of the present invention equipped with a cooling system. An inner vacuum vessel 290 surrounds the periphery of the magnetic shield plate 281 of the magnetometer having the shape shown in FIG. Inner vacuum vessel 29
0 inside the outer vacuum vessel 291
Evacuate from 300 to vacuum. By evacuating to a vacuum, the magnetometer and the object to be measured are insulated. The inner wall of the reactor pressure vessel, which is one of the measurement samples 2, is immersed in about 60 degrees of reactor water at the time of normal inspection. To improve the thermal insulation efficiency between these reactor water and the magnetometer, multilayer insulation is used. The layer 310 is adhered to the inside of the outer vacuum vessel. Inside the inner vacuum vessel 290,
Liquid helium or liquid nitrogen is introduced from the supply flexible tube 320 and discharged from the return flexible tube 330.
With these cooling media, the print coil 4 and the lead wire
24. Cooled to a temperature that operates with coil S25, rfSQVID28 and superconductivity. Here, when the print coil 4 is Nb-Ti based and rf
When the SQVID 28 is made of an Nb-based superconducting material, liquid helium is introduced, and when both are made of a Y-based, Bi-based, or Tl-based superconducting material, liquid nitrogen is introduced. Structures such as the outer vacuum vessel 291 of the magnetometer are made of stainless steel or reinforced plastic.

FIG. 27 is a cross-sectional view illustrating a case where the magnetometer of the present invention is applied to a nuclear power container.

When detecting high temperature aging embrittlement damage of the reactor wall 933 of the nuclear pressure vessel, the outer vacuum vessel 29 equipped with the magnetometer of the present invention is used.
Drive Shaft (1) 934 and Drive Shaft (2) 935
And each drive shaft is connected in a gearbox 936. The outer vacuum vessel 291 is moved in the X direction by the X-axis motor 937, and is also moved in the Y direction by the Y-axis motor 938. The gear box 936 is supported by a frame 939, and the frame 939 is connected to a furnace wall 93 via a suction cup 940 as shown in the figure.
3 Fix it at 4 places on the top. Here, the suction between the suction cup 940 and the furnace wall 933 is performed by discharging the furnace water in the suction cup 940 using a vacuum pump 941. In addition, frame 939 is cable 9
It can be moved up and down and left and right by a crane suspended at 42 and placed on the top of the pressure vessel with the lid open.In addition, 930 is a rudder pipe connected to a vacuum chamber with a helium tube, , A wiring system for connecting the magnetometer and the outside is housed while being sealed.

Examples of the printed coil shown in FIGS. 1 and 20 to 25 are shown in FIGS. The printed coil (1) 12 shown in FIG. 2 has a shape in which superconducting ribbons are arranged in parallel, and measures the magnetic flux passing through the grooves (1) 15 grooves (3) 15 grooves (3) 17 forming a superconducting loop. The groove (2) 16
Cannot measure the magnetic flux passing through the portion, and that portion becomes a loss. In the printed coil (2) 13 of FIG. 3 and the printed coil (3) 14 of FIG. 4, the groove (4) 18 is formed by the superconducting ribbon (1) 21 and the superconducting ribbon (2).
The self-inductance of the loop consisting of the loop 22 and the magnetic flux signal strength corresponding to the self-inductance and the magnetic flux signal strength corresponding to the self-inductance by the inner superconducting ribbon are added to the groove (5) 19, and the groove is eventually formed. (6) 20 is a place where the magnetic flux signal intensity is highest. The printed coil (3) 14 has an effect of lowering the resistance depending on the type of current since the corners are rounded as compared with the printed coil (2) 13. The above-described print coil is effective for a metal material sample or the like in which precipitates affecting magnetic flux are locally distributed.

(Sensitivity and Signal Resolution of Magnetic Flux Sensor) The pickup coil P23 in FIG. 5 is connected to the coil S25 via the lead wire 24, and forms a superconducting closed circuit 26 as a whole. The coil S25 binds with rfSQUID28 and M _S for one have a Jiyosefuson junction 27. l _d is the self-inductance of the lead wire, which is sufficiently twisted to make L _d as small as possible. When the pickup coil shown in FIGS. 2 to 4 is used, the sensitivity and signal resolution of the magnetometer are improved as compared with the conventional circular multi-turn pickup coil. The above reason will be described with reference to FIG. The self-inductance of the pickup coil P23 is L _P and the number of turns is
n _P , the cross-sectional area is A _P , the equivalent average diameter of a circular single-turn coil is d, the self-inductance of the coil S25 is L _S , the number of turns is n _S ,
Assuming that the winding has a self-inductance, the pickup rate of the magnetic flux from the pickup coil P corresponding to the sensitivity of the magnetometer to the coil S25 from L _PO and L _SO 23 is shown by the equation in FIG. ε
Is maximum when L _P = L _S , and the maximum sensitivity is as shown in the figure. Therefore, the self-inductance of one turn of the detection coil
By reducing L _PO , the sensitivity ε of the magnetometer and the signal resolution ΔΦ are improved. Pickup coil (1) 1
5, (2) 16, (3) 17 has the effect of reducing the L _PO than the sectional area A _P is small average diameter d is increased by n _P = 1 as compared with the conventional pickup coil.

Further, as a conventional countermeasure against noise, as shown in FIG. 7, the entire magnetic sensor other than the print coil side for detecting the magnetic flux from the measurement sample 2 is covered with a magnetic shield plate 281 such as μ metal to reduce the external magnetism. Up to about ^-1 G. Next, the lead wire 24 of the magnetic flux transmission circuit is magnetically shielded by a magnetic shield tube 282 such as lead, and the SQUID 28 and the coil S25 for transmitting magnetic flux to the SQUID 28 are formed by a magnetic shield material 283 such as a PC material. By reducing the noise, noise due to extraneous magnetism is sufficiently suppressed.

(Application Example of the Present Invention) In FIG. 8, the measurement sample 2 in FIGS. 1, 20 to 25 is a ferrite-containing stainless steel 29 used in a high-temperature environment such as a chemical plant and a nuclear power plant. If the ferrite-containing stainless steel 29 is used for a long time in a high-temperature environment, the internal structure is changed, and the strength is reduced. As shown in FIG. 8, the change in the internal structure is due to the spinodal decomposition of the ferrite phase 30 in the steel.
And the G phase 32 precipitates. First, when the sample is demagnetized by the demagnetizer and magnetized by the excitation system provided with the excitation coil, the lines of magnetic force 33 generated from the ferrite phase 30 are as shown in FIG. However, the conventional pickup coil 34
In the case of using, since the coil was far from the sample, the measurement in the region where the magnetic flux density was high could not be performed, and the measurement sensitivity of the magnetic flux density change due to the minute precipitate was low. On the other hand, when the printed coil 4 of the present embodiment is used, the coil can be brought close to the minute precipitate, so that the change in the magnetic flux density due to the α ′ phase 31 and the G phase 32 can be measured with high sensitivity. Further, by inserting a thin plate material having a relative magnetic permeability close to 1 to hold the printed coil 4, the fluctuation of the distance between the printed coil 4 and the ferrite-containing stainless steel as a measurement sample is reduced, It is possible to further improve the sensitivity.

FIG. 9 shows the distribution of the lines of magnetic force when the ferrite-containing stainless steel 29 is measured by the magnetic sensor shown in FIG. Compared to the case of only the print coil 4 shown in FIG. 8, the magnetic lines of force are induced by the print coil core 6, and the leakage magnetic flux is reduced. Further, as shown in FIG.
When measured by the magnetic sensor shown in FIG. 24, the magnetic field lines (2) 35 that could not reach the print coil in FIG. 9 are induced by the print coil core 8 made of a soft magnetic material.
Further, it is possible to suppress leakage magnetic flux, improve sensitivity, and reduce noise.

FIG. 11 is a magnetic flux density 37 (B) -magnetomotive force 36 (H) characteristic diagram of a ferrite-containing stainless steel 29 which is a receiving material before being used for a long time in a high temperature environment. Magnetoforce 36
The magnetization curve forms a magnetic hysteresis loop 38,
The maximum magnetic flux density 39, the residual magnetic flux density 40, the coercive force 41, or the hysteresis area 42 can be measured. Further, the maximum magnetic flux density 39 depends on the initial ferrite amount of the material. In contrast, for deteriorated materials that have been used for a long time in a high-temperature environment,
When measured using the conventional pickup coil 34 and the printed coil 4 of the present invention, the magnetic flux density 37-magnetomotive force 36 characteristics are as shown in FIGS. 12 and 13, respectively. As is clear from the figure, the use of the magnetic sensor of the present invention has an effect that the measurement sensitivity of the hysteresis area 42 and the residual magnetic flux density 40 is greatly improved.

(Method of Manufacturing Print Coil) A method of manufacturing a print coil will be described. Sputter evaporation, electron beam evaporation, laser sputter evaporation, MBE evaporation, MOCVD evaporation, and spray pyrolysis evaporation are used as print coil manufacturing methods.

A case where a print coil is formed by sputtering vapor deposition will be described. In sputter deposition, a substrate made of, for example, MgO is placed in a production container, and a mask previously created according to the shape of the printed coil is placed on the substrate, and a superconducting material sintered body such as BiSiCaCuO placed in the production container is formed. A superconducting thin-film coil is formed on the substrate by sputtering the target in a rare gas plasma such as argon Ar.

A case where the electron beam is formed by the electron beam evaporation method will be described. In the electron beam evaporation, a metal source made of a superconducting material is irradiated with an electron beam in a high vacuum to vaporize a metal in vacuum and deposit the flux on a substrate. The higher the degree of vacuum, the better, for example, about 10 ^-6 Pa is desirable, but even at a degree of vacuum of about 10 ^-3 Pa, the substrate temperature 500
Transition temperature Tc on a quartz substrate at a deposition rate of 10 nm / min.
= 9.8 ゜ K Nb thin film can be formed, and this transition temperature
Tc is higher than bulk.

FIG. 14 is a view for explaining a method of forming a thin-film printed coil of the present invention using electron beam evaporation as an example. For example, 10 ^-6
A mask (mold) 44 previously prepared according to the shape of the printed coil is placed on a quartz substrate 43 in a vacuum of a Torr table, and the substrate is heated and rotated at 600 ° C., and vacuum evaporation is performed from above by electron beam irradiation. The thin film print coil 46 is formed in the groove of the mask 44 by immersing the flux 45 of the superconducting constituent material, for example, Nb. Here, several tens of mm / m
A thin film can be grown at a film forming speed of about in, and Tc is higher than that of bulk, and 9.8K can be obtained.

Laser beam deposition will be described. As shown in FIG. 15, for example, a mask (mold) 44 is formed on an MgO substrate, introduced into a vacuum vessel 47, and evacuated to a degree of vacuum of 10 ^-10 to 10 ^-11 Torr. A target 49 made of a superconducting material such as a BiSiCaCuO sintered body is provided at the center of the vacuum container 47, and a laser beam 51 of an excimer laser 50 is irradiated on the target 49 to generate a flux 45, thereby forming a thin film on the substrate 43. Printed coil 46
Grow. The state of the flux 45 is monitored by the quadrupole mass spectrometer 52. For example, a 1 μm superconducting film can be formed by using an ArF excimer laser (wavelength 193 nm) as a laser source and irradiating a laser beam with an output of 30 mJ / pulse at 20 Hz for 20 minutes. Requires a high vacuum,
No substrate heating is required.

An example in which an oxide superconductor printed coil is formed as the MBE deposition method will be described. In ultra-high vacuum (10 ^-10 -1
^0-11 Torr), for example, using a metal Ba, a metal Cu, a metal rare case as an evaporation source containing the elements constituting the superconducting material, and using Sb ₂ O ₃ as a solid oxygen source to heat this evaporation source. Each constituent element is stacked on the MgO substrate (100) surface heated to, for example, 600 ° C. in an atomic layer, and the superconducting film (about 2 μm) is evaporated.
m) is formed.

A case where a printed coil is manufactured by MOCVD deposition will be described.

The MOCVD method is a technique in which a material containing a constituent element of a superconducting material is vaporized, and a film is formed on a substrate heated by carrying each gas with a carrier gas. For example, YBCO
To prepare the film, the organic compound material Y (DPM) ₃ , B
a (DPM) ₂ and Cu (DPM) ₂ are vaporized and the temperature of each gas is set to 130 ~
160 ° C., 280 to 300 ° C., and maintained at 140 to 170 ° C., carried to the reaction chamber at a flow rate per minute 200 cm ³ to try when the Kiyariagasu of Ar. At the same time, purified oxygen gas is also sent to the reaction chamber at a rate of 200 to 500 cm ³ per minute. The substrate temperature is 600 ° C. Under these conditions, a YBCO thin film can be synthesized at a growth rate of 0.1 to 10 μm per hour.

Next, a method of manufacturing a printed coil by the spray biolysis method will be described.

The spray pyrolysis method is a method in which an aqueous solution containing a superconducting substance is sprayed on a heated substrate in the air and then heat-treated in the air to obtain a superconducting film. This method has an advantage that a film can be formed even on a substrate having a complicated shape, the composition ratio of the preparation becomes the film composition as it is, the film formation speed is high, and the film can be easily made thick. For example, in Bi-based superconductors, Bi, S
An aqueous solution is prepared by mixing the respective nitrates so that r, Ca and Cu are in a ratio of 1: 1: 1: 1: 2. Next, when an aqueous solution is sprayed on the substrate heated to 400 ° C. in the air, water as a solvent evaporates instantaneously. Most Cu nitrates turn into oxides in a few seconds, and Bi nitrates also turn into oxides. Finally in the air
When heat treatment is performed at 860 ° C. for 10 minutes, the remaining metal nitrate turns into an oxide, and a superconductor printed coil is formed.

 An example of manufacturing by laser sputter deposition will be described.

The laser sputter deposition method is a method of irradiating a target made of a superconducting material with a laser beam and depositing a flux sputtered from the target on a substrate to obtain a superconducting film. For example, an output from an ArF excimer laser (wavelength 193 nm) with a BiSiCaCuO sintered body as a target on an MgO substrate
Irradiation with a laser beam of mJ / 1 pulse at 20 Hz for 20 minutes results in a 1 μm superconducting film. The deposition is performed in an ultra-high vacuum of the order of 10 ^-10 Torr, and the substrate is not heated.

FIG. 16 shows an example of a procedure for manufacturing a thin plate-shaped printed coil. Ba ₂ YCuO ₇ prepared in advance An oxide having a composition such as _y is mixed and pulverized with a binder. Generally, an epoxy resin or an organic binder is used as the binder. Next, it is formed into a wire by cold working such as an extrusion method, and is changed into a coil shape. Further, the member is made into a thin plate coil 54 by a doctor blade 53. Finally, the thin coil 54 is fired to evaporate the binder and sinter the powder.

 Here, the doctor blade method will be described.

The Tokudah blade method is often used for the production of a raw sheet of a dielectric layer for a multilayer capacitor. In principle, a binder, a plasticizer, a separating agent, and a solvent are uniformly mixed with a ceramic powder and adjusted by defoaming. A method in which a slurry (slurry) is poured onto a flat metal or glass plate, and the thickness of the slurry is adjusted by moving a doctor blade having a flat portion, which is a doctor blade, into contact therewith. For example, when producing a Bi-based superconductor (for example, a tape-like material), the oxide raw material is Bi _0.7 Pb
_By mixing at a composition ratio of _0.3 SrCa ₁ Cu _1.8 O _x , a high Tc phase Bi-based superconductor is produced. This is crushed and mixed with an organic binder to form a slurry. Next, using a doctor blade, apply this slurry on a substrate of polyester film or the like with a width of 125 m.
A thick superconductor film having a thickness of 100 μm and a thickness of 100 μm is formed. A ribbon having a width of, for example, 3 mm and a length of 100 mm is cut out from the thick film into a printed coil shape, and a heat treatment is performed, for example, at 500 ° C. for about one hour.

FIG. 17 shows an example of manufacturing a thin-film print coil. substrate
A negative image of a print coil is formed on the 43 by using a photosensitive resin 53-1 and then a superconducting thin film 54-1 is deposited on the entire surface. Further, the thin film print coil 46 is manufactured by removing the negative image forming substance and the thin film thereon using a solvent.

A case in which the present invention is applied to a Pb-based superconductor will be described more specifically as an example. A negative image of the print coil is created on the substrate 43 using the photosensitive resin 53. Quartz glass or sapphire is used for the substrate, and bisazide, N
Using acetyl 4-nitro-1 naphthylamine.

Next, a superconducting thin film 54 is formed on the entire surface. A Pb-based superconducting material is used, and a vacuum deposition by resistance heating is used as a forming method.
Here, a pure Pb thin film has poor resistance to thermal strain and has poor waterproof (waterproof) sheet, so Au and In are added in addition to Pb. Actually, Au (about 4 W%), In (about 5 to 14 W) %, Eg 12W%), Pb
(About 82 to 88 W%, for example, 84 W%) in this order. Further, the negative image forming substance and the thin film thereon are removed with a solvent, whereby the thin film print coil 46 is manufactured.

As the solvent, for example, an aqueous alkali solution or alcohol is used.

In the above description, the material is one example, and the present invention is applied to other materials.

FIG. 18 shows a production example of a thin-film printed coil as a similar example. A superconducting thin film 54 is formed on a substrate 43, and a photosensitive resin
The print coil forms a positive pattern 55 of the print coil.
Next, the negative pattern 56 is removed by chemical etching, and the photosensitive resin 54 remaining on the positive pattern 55 is dissolved and removed with a solvent, whereby a thin-film print coil 46 is formed.

The print coil shown in FIGS. 3 and 4 has an intersection where the print coils overlap. The shape and manufacturing method of the intersection will be described using the printed coil in FIG. 4 as an example.

FIG. 28 is a schematic view of the manufacturing process of the intersection of the superconducting printed coil shown in FIG. 4, and FIG. 29 is a schematic view of the intersection. In Fig. 28, it becomes superconducting at 9.5K, for example.
Nb was deposited on a glass substrate 43 by electron beam evaporation (6 KW)
Vapor deposition is performed at a growth rate of 0 (Å / min) for 50 minutes to form an Nb superconducting film (1) 440 having a thickness of 10 μm, thereby producing a printed coil. A mask (1) 450 is placed on the superconducting film (1) 44, and an SiO ₂ or LiF insulating film 460 of about 15 μm is formed from above the mask by sputtering. At that time, care must be taken that the insulating film will not be a Josephson junction unless the insulating film is locally thinned (several tens of mm). Further, the mask (1) 45 is removed, the mask (2) 451 is placed as shown in the figure, and a 20 μm Nb film is deposited from above by electron beam evaporation (6 KW), and the mask (2) 451 is removed. An intersection as shown in the figure can be produced. However, by extending the insulating film 460 in the X direction more than the superconducting film (1) 440, the superconducting film (1) 440 and the superconducting film (2) 441 do not form bridges to form a Josephson junction.

Further, a method of manufacturing a superconducting printed coil will be described.

FIG. 30 shows another embodiment of the method of manufacturing a superconducting printed coil.

A Ti (circuit pattern) 562 is fitted into the groove of the Nb substrate 561 having a groove corresponding to the negative of the circuit pattern. This metal plate 563 made of Cu-Sn alloy is placed on this Nb substrate
Are laminated and joined to form a laminate of an Nb substrate sandwiching Ti and a Cu-Sn alloy plate. The laminate is irradiated with a laser beam along the Ti pattern to cause a diffusion reaction between Nb and Sn on both substrates and to diffuse Ti to obtain an Nb ₃ Sn—Ti superconducting circuit 564. Surrounding Nb ₃ Sn layer (layer outside pattern)
Is removed by chemical means (such as etching) or cutting.

Further, as an example of manufacturing a Y-Ba-Cu-O-based coil, the 31st
There is a method as shown in the figure. First, the ingot 565 of the Y-Ba-Cu ternary alloy is rolled to form the substrate 566. On this substrate 566, a polymer material shielding sheet 567 such as polyimide, in which a circuit pattern is cut, is attached. The substrate with this sheet is
When an electric current is applied to the aqueous solution while immersed in an alkaline aqueous solution such as that described above, an oxide layer 567 is formed by anodic oxidation in the notched portion of the sheet (exposed portion of the substrate). Next, this substrate is heat-treated at 800 to 950 ° C. for 5 to 100 hours. By this treatment, oxygen in the oxide layer and each element of the substrate diffuse and react with each other, and the oxide-based superconducting coil 568 (Y ₁ Ba ₂ Cu ₃ O
_4-x ) is obtained. Unnecessary portions may be deleted chemically or mechanically.

FIG. 19 shows an embodiment of the production of a thin-film print coil. A superconducting thin film 54 is formed on a substrate 43, and a focused ion beam 58 is irradiated onto the thin film from a liquid metal ion source 57 to perform sputtering. In addition, the focused ion beam 58
A focusing control 60 is performed at 59, and an ion beam scanning control 61 and a positioning control 62 of the substrate 43 are performed to control the thin film print coil 46.
Is prepared. Although there are various embodiments, for example, a superconducting material YBa ₂ Cu ₃ O _7- δ on a glass, quartz, YSZ (yttria-stable zirconia) substrate can be processed using Ca, Au as a liquid metal ion source. Of course, it can be applied to other materials. According to the embodiment of the present invention, there is an effect that a printed coil can be manufactured without greatly increasing the manufacturing process of the conventional superconducting thin film or wire.

In the production example of the thin-film print coil, if a high-permeability material in which the thin film does not cause phase separation when used as the substrate is used as the substrate for manufacturing the print coil, the produced print coil may be removed from the substrate without removing the core. There is an effect that it can be used as. Further, by adopting a thin substrate as a general substrate having a low magnetic permeability, there is also an effect that the substrate can be used as a member for defining the distance between the measured object and the printed coil.

〔The invention's effect〕

According to the present invention, in a magnetic sensor including a superconducting quantum interferometer and a magnetic flux transformer, the magnetic flux transmissibility of the magnetic flux transformer and the sensitivity and signal resolution as a magnetic flux meter can be improved. There is an effect that the degree of deterioration of ferrite-containing stainless steel used in a high-temperature environment can be detected with high accuracy.

[Brief description of the drawings]

1, 20, 21, 22, 23, 24 and 25 are longitudinal sectional views of a magnetometer according to an embodiment of the present invention, respectively.
2, 3, and 4 are top views showing examples of a printed coil used in the present invention, FIG. 5 is a diagram showing the principle configuration of a magnetometer according to an embodiment of the present invention, and FIG. FIG. 7 is a flow chart showing a detection example of the present invention, FIG. 7 is a schematic sectional view of a magnetometer for suppressing external magnetic noise, FIG. 8 is a schematic sectional view showing a difference between a conventional method and a magnetic flux measurement state according to the method of the present invention, FIG. 9 is a schematic sectional view showing a state of magnetic flux measurement by the magnetic sensor of FIG. 21,
10 is a schematic sectional view showing the state of magnetic flux measurement by the magnetic sensor of FIG. 24, FIG. 11 is a characteristic diagram showing the magnetic hysteresis of the receiving material of ferrite-containing stainless steel, and FIG. FIG. 13 is a characteristic diagram showing the magnetic hysteresis of the deteriorated material measured by the conventional method, FIG. 13 is a characteristic diagram showing the magnetic hysteresis of the deteriorated material measured by the method of the present invention, FIG. 14, FIG. 15 and FIG. FIG. 16 is a schematic view of an apparatus showing one embodiment of a method of manufacturing a thin-film print coil according to the present invention. FIG. 16 is a flowchart showing one embodiment of a manufacturing procedure of a thin-plate print coil. FIG. 17 and FIG. FIG. 26 is a flow chart showing one embodiment of the method of manufacturing a thin film printed coil of the present invention, FIG. 26 is a schematic diagram of a magnetometer when a superconductor material operating at liquid helium temperature is used for a magnetic flux transformer and SQVID, FIG. The figure is based on the magnetometer of the present invention. Schematic diagram for detecting the magnetic characteristics of the reactor wall of the nuclear power plant, FIG. 28 is a diagram showing a method of manufacturing the intersection of the printed coil of the present invention,
FIG. 29 is a schematic view of the intersection of the printed coil of the present invention,
FIG. 30 and FIG. 31 are explanatory diagrams each showing an example of a method of manufacturing a printed coil. 1 ... superconducting quantum interferometer, 2 ... measurement sample, 3 ... pickup coil, 4 ... print coil, 5 ... member,
6 core for print coil (1), 7 core for print coil (2), 8 core for print coil (3), 9 core for print coil (4), 10 lower print coil , 11 …… Top printed coil, 12 ……
Print coil (1), 13 ... Print coil (2)
14 ... Print coil (3), 15 ... Groove (1), 16 ...
... groove (2), 17 ... groove (3), 18 ... groove (4),
19 ... groove (5), 20 ... groove (6), 21 ... superconducting ribbon (1), 22 ... superconducting ribbon (2), 23 ... pick-up coil P, 24 ... lead wire, 25 ... Coil S, 26
…… superconducting loop, 27 …… Josephson junction, 28 …… rf
SQUID, 28-1 ... magnetic shield plate, 28-2 ... magnetic shield tube, 28-3 ... magnetic shield material, 29 ... ferrite-containing stainless steel, 30 ... ferrite phase, 31 ... α '
Phase, 32: G phase, 33: Magnetic field line, 34: Conventional pickup coil, 35: Magnetic field line (2), 36: Magnetomotive force, 37 ...
... magnetic flux density, 38 ... magnetic hysteresis loop, 39 ... maximum magnetic flux density, 40 ... residual magnetic flux density, 41 ... coercive force, 42 ...
... hysteresis area, 43 ... substrate, 44 ... mold, 45 ... flux, 46 ... thin-film print coil, 47 ... vacuum vessel, 48 ... vacuum exhaust, 49 ... target, 50 ... excimer laser, 51 …… Laser light, 52 …… Quadrupole mass spectrometer,
53: Doctor blade, 54: Thin coil, 53-1
... photosensitive resin, 54-1 ... superconducting thin film, 55 ... positive pattern, 56 ... negative pattern, 57 ... liquid metal ion source, 58 ... focused ion beam, 59 ... Einzel lens, 60 ... ... Focusing control, 61 ... Ion beam scanning control, 62
…… Positioning control, 63 …… Inner vacuum vessel, 64 …… Multilayer insulation material, 65 …… Vacuum flexible pipe, 66 …… Supply flexible pipe, 67 …… Return flexible pipe, 68 …… Outer vacuum vessel, 69: Furnace wall, 70: Drive shaft (1), 71
…… Drive shaft (2), 72 …… Gear box, 73 ……
X-axis motor, 74 ... Y-axis motor, 75 ... frame, 76 ...
... Suction cup, 77 ... Vacuum pump, 78 ... Cable, 79 ... Substrate, 80 ... Superconducting film (1), 81 ... Superconducting film (2), 82
... Mask (1), 83 ... Mask (2), 84 ... Insulating film, 85 ... Nb substrate, 86 ... Ti (circuit pattern), 87
…… Cu-Sn alloy metal plate, 88… Nb ₃ Sn-Ti superconducting circuit, 89 …… Ingot, 90 …… Substrate, 91 …… Polymer shielding sheet, 92 …… Oxide layer , 93 ... Oxide superconductor coil.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuichi Ishikawa 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. In the laboratory (72) Inventor Yuko Oguchi 502 Kandate-cho, Tsuchiura-city, Ibaraki Pref. Hitachi Machinery, Ltd. (56) References JP-A-59-133474 (JP, A) JP-A-62-58179 (JP, A JP-A-62-22057 (JP, A) JP-A-59-177474 (JP, A) JP-A-61-210942 (JP, A) JP-A-56-108973 (JP, A) 124781 (JP, A) Fully open 1986-6-1659 (JP, U) Fully open 63-2,587 (JP, U) Fully open, 62-182476 (JP, U) Fully open, 60-168078 (JP, U) 62-182475 (JP, U) Public Akira 57-56218 (JP, Y2) real public Akira 63-1251 (JP, Y2) measurement and control Vol. 26 No. 11 PP. 27-30 IEICE 70th Anniversary Commemorative National Convention S'6-1

Claims (4)

(57) [Claims] An object for detecting the degree of embrittlement of a metal material, wherein the metal material is used as an object to be measured, and an excitation coil for applying a magnetic field to the object is obtained. A superconducting quantum interference device for detecting a change in magnetic characteristics, and a superconducting closed circuit in which a probe coil or a pickup coil is arranged so as to face the device under test, wherein the superconducting quantum interference device is provided from the superconducting closed circuit. The printed coil made of a superconducting material is applied to the probe coil or the pickup coil, and the superconducting closed circuit is disposed within the reach of the generated magnetic flux and magnetically coupled to the superconducting closed circuit. The coil for magnetic coupling is connected with a lead wire to form a closed circuit made of a superconducting material as a whole, the lead wire is covered with a magnetic shielding tube, and the A coil for transmitting magnetic flux to the superconducting quantum interference device and the superconducting quantum interference device are covered with a magnetic shielding plate in a material closed circuit, and the whole except for the print coil side is further covered with a magnetic shielding plate. Features magnetic flux meter. 2. The device according to claim 1, wherein said print coil is fitted into said concave portion of a plate-shaped core having a concave portion, and said core is formed of a soft magnetic material to control magnetic flux leakage. Magnetic flux meter. 3. The magnetometer according to claim 1, further comprising a member for defining a distance between the printed coil and the object to be measured. 4. A deterioration detection method for applying a magnetic field to a metal material as an object to be measured and monitoring a change in magnetic characteristics specific to the object to be measured, and detecting a degree of deterioration of the object to be measured from the change in the magnetic characteristics. 4. A method for detecting deterioration of a metal material according to claim 1, wherein the change in the magnetic property is measured using the magnetometer according to claim 1.