JP2008192499A - Filling equipment of raw material powder of oxide superconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a filling equipment for raw material powder of an oxide superconductor with a critical current value improved by alleviating infiltration of impurity gas at filling and sealing of raw material powder in a metal tube. <P>SOLUTION: The filling equipment 100 for raw material powder of an oxide superconductor is provided with a powder supply part 110, a powder filling part 120, a sealing part 140, an airtight container 160, and an exhaust part 150. The powder supply part 110 supplies raw material powder 11 of the oxide superconductor. The powder filling part 120 fills the raw material powder 11 in the metal tube 12 with one end open. The sealing part 130 seals the metal tube 12 with the raw material powder 11 filled. The airtight container 160 has the powder supply part 110, the powder filling part 120, and the sealing part 140 arranged inside. The exhaust part 150 exhausts atmospheric gas from inside the airtight container 160. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an oxide superconductor raw material powder filling apparatus, for example, a Bi2223 superconducting wire raw material powder filling apparatus.

  An oxide superconducting wire is formed from a raw material powder of an oxide superconductor into a long tape-shaped wire by a powder-in-tube method. In this method, raw material powder is filled into a metal tube to produce a single core material. Then, a multi-core structure can be obtained by bundling a plurality of single core materials and inserting them into the sheath portion. An oxide superconducting wire having superconductivity can be produced by subjecting the multi-core busbar to drawing, rolling, etc. to form a wire, and then heat treatment and sintering.

  In such a manufacturing method, when a raw material powder is filled in a metal tube in the air, 1000 ppm or more of an impurity gas such as a polar molecule is adsorbed. Thereafter, in the forming process such as wire drawing and rolling, the raw material powder is densified, so that the adsorbed impurity gas creates voids between the crystals of the oxide superconductor, or the impurity gas and the raw material powder are combined. As a result, the oxide superconducting filament is disturbed and the critical current value is lowered.

  Further, when the raw material powder is filled in the metal tube in the atmosphere, the filling density cannot be increased to 30% or more due to air resistance. Since there are many voids in the powder region with a low packing density, there has been a problem that the coarsening progresses in a forming process such as wire drawing or rolling, causing disorder in the orientation of the oxide superconducting crystal, resulting in a decrease in the critical current value.

  In addition, heating may be performed to remove the adsorbed impurity gas. However, since the differential pressure between the inside and the outside of the metal tube during heating is large, the packing density of the raw material powder is reduced. When the packing density of the raw material powder is lowered, there is a problem that the critical current value is similarly lowered.

Therefore, for the purpose of removing the impurity gas in the metal tube, Japanese Patent Application Laid-Open No. 2004-87488 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2001-184958 (Patent Document 2) describe a metal tube filled with raw material powder. It is disclosed that the opening is sealed in a decompressed state.
JP 2004-87488 A Japanese Patent Laid-Open No. 2001-184958

  However, even in the methods disclosed in Patent Documents 1 and 2, since impurity gas is adsorbed when the raw material powder is filled in the metal tube, there is still room for improvement in removing the impurity gas.

  Therefore, an object of the present invention is to reduce the intrusion of impurity gas when filling and sealing a metal tube with raw material powder, and to improve the critical current value of the raw material powder of the oxide superconducting wire body. It is to provide a filling device.

  An oxide superconductor raw material powder filling apparatus according to the present invention includes a powder supply section, a powder filling section, a sealing section, an airtight container, and an exhaust section. The powder supply unit supplies raw material powder of the oxide superconductor. The powder filling unit fills the raw material powder into a metal tube having one opened. The sealing portion seals the metal tube filled with the raw material powder. An airtight container arrange | positions a powder supply part, a powder filling part, and a sealing part inside. The exhaust unit exhausts atmospheric gas from the inside of the airtight container.

  According to the raw material filling apparatus for an oxide superconductor of the present invention, the pressure inside the hermetic container can be adjusted to a pressure lower than the atmospheric pressure at the exhaust part, so when filling the raw material powder into the metal tube at the powder filling part. Further, the impurity gas can be reduced, and the metal tube can be sealed with the impurity gas reduced in the sealing portion. Therefore, when the raw material powder filled and sealed in the metal tube is formed into an oxide superconductor by the oxide superconductor raw material powder filling apparatus of the present invention, the orientation of the oxide superconductor is disturbed by the impurity gas. Can be prevented. Therefore, an oxide superconductor capable of improving the critical current value can be obtained.

  Preferably, the oxide superconductor raw material powder filling apparatus further includes a heating unit which is disposed inside the hermetic vessel and heats the metal tube filled with the raw material powder.

  Thereby, more impurity gas adsorbed to the raw material powder filled in the metal tube can be removed.

  Preferably, in the oxide superconductor raw material powder filling apparatus, the hermetic container includes a main chamber and a sub chamber connected to the main chamber via an opening / closing member, and the powder supply unit is disposed inside the sub chamber. The powder filling part, the heating part, and the sealing part are arranged inside the main chamber.

  As a result, when the raw material powder is put into the powder supply unit from the outside of the hermetic container, only the sub chamber can be opened to the atmosphere by closing the opening / closing member without opening the whole hermetic container to the atmosphere. In addition, when the metal tube (wire) sealed by the sealing portion is carried out of the hermetic container, only the main chamber is opened to the atmosphere by closing the opening / closing member without opening the entire hermetic container to the atmosphere. Can do. That is, since only one of the main chamber and the sub chamber can be opened to the atmosphere as necessary, the throughput of filling the raw material powder into the metal tube can be improved.

  Preferably, the oxide superconductor raw material powder filling apparatus further includes an optical non-contact measurement unit that is disposed inside the hermetic container and measures the amount of the raw material powder filled in the metal tube by the powder filling unit. Yes.

  Thereby, the height at which the raw material powder is filled in the metal tube can be measured. Therefore, the packing density of the raw material powder filled in the metal tube can be measured. Moreover, since the light used for the measurement can measure the packing density without coming into contact with the raw material powder, it is possible to prevent impurities from being mixed when the packing density is measured.

  The “optical non-contact measurement unit” includes an irradiation device, a reflecting mirror disposed above the opening of the metal tube in the powder filling unit, and a light receiving device, and the irradiation device is directed toward the reflecting mirror. The reflecting mirror reflects the light irradiated by the irradiation device toward the raw material powder filled in the metal tube and reflects the light reflected from the raw material powder toward the light receiving device. The device receives light reflected from the reflector.

  Preferably, in the oxide superconductor raw material powder filling apparatus, the powder supply unit includes a control unit that controls the amount of the raw material powder supplied to the powder filling unit.

  Thereby, desired raw material powder can be supplied. Also, by supplying a certain amount to the powder filling unit, the packing density of the raw material powder filled in the metal tube can be made constant, so when forming the strand filled with the raw material into the metal tube into an oxide superconductor, Occurrence of orientation disorder of the oxide superconductor can be further prevented.

  In the oxide superconductor raw material powder filling apparatus, the powder supply unit preferably includes a stirring unit for stirring the raw material accommodated therein.

  Thereby, the raw material powder supplied to the powder supply part can be stirred. Therefore, the raw material powder can be prevented from aggregating by flowing the raw material powder.

  In the oxide superconductor raw material powder filling apparatus, preferably, the powder filling portion includes a vibration portion that applies vibration to the metal tube filled with the raw material powder.

  Thereby, in the raw material powder with which the inside of the metal tube was filled, the coupling | bonding of particle | grains by van der Waals force, liquid bridge | crosslinking adhesive force, etc. can be broken. Therefore, it can prevent that raw material powder aggregates.

  In the filling apparatus for raw material powder of the oxide superconductor, preferably, the sealing portion includes a welding portion for locally heating a sealing member for sealing the metal tube filled with the raw material powder. Thereby, when sealing a metal tube, the quality change of raw material powder can be suppressed.

  As described above, according to the raw material powder filling apparatus for oxide superconductor of the present invention, the powder filling part and the sealing part are arranged in the hermetic container. Further, the intrusion of impurity gas can be reduced when sealing. Therefore, when the raw material powder is formed into an oxide superconductor, the critical current value of the oxide superconductor can be improved.

  Hereinafter, embodiments and examples of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a schematic diagram for explaining a filling apparatus for raw material powder of an oxide superconductor in Embodiment 1 of the present invention. FIG. 2 is a schematic diagram showing an apparatus for measuring the height of the raw material powder filled in the metal tube in the first embodiment of the present invention. With reference to FIG. 1 and FIG. 2, the oxide superconductor raw material powder filling apparatus 100 in Embodiment 1 of the present invention will be described.

  As shown in FIG. 1, the raw material powder filling apparatus 100 for the oxide superconductor in Embodiment 1 includes a powder supply unit 110, a powder filling unit 120, a heating unit 130, a sealing unit 140, and an exhaust unit. 150, an airtight container 160, a reflecting mirror 171, and an irradiation and light receiving device 172.

  Specifically, the powder supply part 110 contains the supply member 111, the powder container 112, the control part 113, and the stirring part 114, for example.

  The supply member 111 supplies the raw material powder 11 of the oxide superconductor to the powder filling unit 120. The supply member 111 preferably has a shape that can easily supply the raw material powder 11 to the powder filling unit 120. For example, the supply member 111 supplies the raw material powder 11 to the powder filling unit 120. The lower side which is the side to be opened is opened, and the shape is tapered (tapered) as it approaches the powder filling portion 120, and can be a cylindrical shape having a space inside.

  The powder container 112 is filled with the raw material powder, and the raw material powder 11 is put into the supply member 111 as necessary. The powder container 112 supplies the raw material powder 11 to the supply member 111, for example, when vibration is applied from the outside.

  The control unit 113 controls the amount of the raw material powder 11 supplied to the powder filling unit 120. For example, the control unit 113 monitors a decrease amount of the weight of the raw material powder 11 accommodated in the supply member 111 and changes the supply amount from the powder container 112 to the supply member 111 according to the decrease amount. When the powder container 112 supplies the raw material powder 11 to the supply member 111 by vibration, the control unit 113 changes the frequency applied to the powder container 112 according to the amount of decrease being monitored.

  The stirring unit 114 stirs the raw material powder 11 accommodated in the supply member 111. As shown in FIG. 1, the stirring unit 114 is not particularly limited to a wing-shaped member disposed inside the supply member 111, and for example, a rod-shaped member is disposed outside the supply member 111, The raw material powder 11 may be stirred.

  The powder filling unit 120 includes, for example, a robot arm 121, a filling member 122, and vibration units 123 and 124.

  The robot arm 121 is a member that holds the metal tube 12. The robot arm 121 is preferably capable of moving the metal tube 12 in the direction in which the metal tube 12 extends (the vertical direction in FIG. 1), and more preferably capable of moving the metal tube 12 in any direction. When the robot arm 121 is movable, the distance for moving the metal tube 12 is preferably variable. When the robot arm 121 can move the metal tube 12, the metal tube 12 can be moved to the vibrating parts 123 and 124, and the raw material powder in the metal tube 12 is also vibrated by the robot arm 121, so that the fan The bond of the particles of the raw material powder 11 due to the Delwars force or the liquid crosslinking adhesion force can be broken.

  The filling member 122 preferably has a shape that facilitates filling of the raw material powder 11 into the metal tube 12. For example, the filling member 122 is relatively upward on the side that receives the raw material powder from the powder supply unit 110 and the raw material powder 11 into the metal tube 12. The relatively lower side which is the side to be filled is open and has a tapered shape (tapered shape) as it approaches the metal tube 12, and can be formed into a cylindrical shape having a space inside.

  The vibration parts 123 and 124 apply vibration to the metal tube 12 filled with the raw material powder 11. For example, as shown in FIG. 1, the vibration unit 123 is a Eurus motor disposed under the metal tube support base 125. The vibration unit 123 can arbitrarily change the vibration frequency to be generated. Moreover, the vibration part 124 has a pipe tapping mechanism, for example. That is, the vibration unit 123 can give a slight vibration to the metal tube 12, and the vibration unit 124 can give a large vibration to the metal tube 12. Therefore, in order to cut | disconnect the coupling | bonding of the raw material powder 11 couple | bonded by various factors according to the degree of aggregation of the raw material powder 11 inside the metal tube 12, at least any one of the vibration parts 123 and 124 is operated. Can do.

  The heating unit 130 heats the metal tube 12 filled with the raw material powder 11. The heating unit 130 is preferably a plurality of heaters that can heat the metal tube 12 independently, for example.

  The heating unit 130 preferably has the ability to heat the metal tube 12 to 100 ° C. or more and 900 ° C. or less, and more preferably has the ability to heat the metal tube 12 to 100 ° C. or more and 800 ° C. or less. It is even more preferable that it has the ability to be heated to 500 ° C. or higher and 800 ° C. or lower. When the temperature is 100 ° C. or higher, the impurity gas adsorbed on the raw material powder 11 filled in the metal tube 12 can be easily removed. When the temperature is 500 ° C. or higher, the impurity gas adsorbed on the raw material powder 11 is more easily removed. On the other hand, in the case of 900 degrees C or less, the raw material powder 11 does not melt | dissolve. In the case of 800 ° C. or lower, the raw material powder 11 is difficult to dissolve.

  The sealing part 140 includes, for example, a welded part 141, a mounting table 142, and a sealing member pressing part 143.

  The welded portion 141 locally heats the sealing member 13 that seals the metal tube 12 filled with the raw material powder 11. With the welding portion 141, the opening at the end of the metal tube 12 can be sealed with the sealing member 13. Moreover, the quality change of the raw material powder 11 can be suppressed by heating locally.

  The welded portion 141 may be, for example, electron beam welding or induction heating. The induction heating method is a method in which the metal tube 12 is self-heated by a high-density eddy current in the vicinity of the surface of the metal tube 12 that is induced from a coil connected to an AC power source (not shown). By employing the induction heating method, the heat energy per unit time supplied to the unit area of the metal tube 12 is large, and the metal tube 12 itself is heated, so that the heat loss is small (heating efficiency is good).

  The mounting table 142 is a member for mounting one or more sealing members 13. If a plurality of sealing members 13 can be mounted on the mounting table 142, it is not necessary to carry the sealing member 13 into the airtight container 160 every time the metal tube 12 is sealed. Further, if a plurality of metal tubes 12 can be arranged in the airtight container 160, the metal tubes 12 can be continuously sealed.

  The sealing member pressing portion 143 is a member for applying pressure to the sealing member 13 disposed on the opening of the metal tube 12. Thereby, the sealing member 13 can be firmly fitted into the opening of the metal tube 12.

  As shown in FIGS. 1 and 2, the reflecting mirror 171 is disposed above the opening of the metal tube 12 in the powder filling unit 120, and the raw material powder 11 filled with the light irradiated from the irradiation device 172 a is provided. The reflected light is reflected toward the light receiving device 172b.

  The irradiation and light receiving device 172 is an optical non-contact measuring unit that measures the amount of the raw material powder 11 filled in the metal tube 12 by the powder filling unit 120. The irradiation and light receiving device 172 includes an irradiation device 172a and a light receiving device 172b. The irradiation device 172a irradiates the reflecting mirror 171 with light. The light receiving device 172b receives light reflected from the reflecting mirror 171. The irradiation device 172a and the light receiving device 172b may be one device or different devices. As the irradiation and light receiving device 172, for example, a laser distance meter can be applied.

  As shown in FIG. 2, by using a reflecting mirror 171, an irradiation device 172a, and a light receiving device 172b, for example, by measuring the time until the irradiated light returns as reflected light, the inside of the metal tube 12 is measured. The height H up to the top of the filled raw material powder 11 can be measured.

  In addition, although it is preferable to measure using the light which is a non-contact type measuring method, it is not limited to this, For example, you may apply the contact type method which hangs a weight and utilizes the tension change.

  The exhaust unit 150 exhausts atmospheric gas from the inside of the airtight container 160. The exhaust part 150 preferably has the ability to adjust the inside of the hermetic container 160 to a pressure of 1000 Pa or less, more preferably 0.001 Pa to 900 Pa, and even more preferably 1 Pa to 300 Pa. When filling the metal tube 12 with the powder filling unit 120 and the sealing unit 140 by setting the pressure to 1000 Pa or less, and when sealing the metal tube 12 filled with the raw material powder 11 with the sealing member 13, Impurities can be prevented from being mixed. By setting the pressure to 900 Pa or less, it is possible to further prevent impurities from being mixed. By setting the pressure to 300 Pa or less, mixing of impurities can be further prevented. On the other hand, by setting the pressure to 0.001 Pa or more, the pressure inside the airtight container 160 can be easily adjusted. By setting it as 1 Pa or more, it is easier to adjust the pressure inside the airtight container 160.

  The airtight container 160 is a container capable of maintaining the inside at a predetermined pressure. The hermetic container 160 includes a main chamber 161 and a sub chamber 162 connected to the main chamber 161 via an opening / closing member 163. In this case, the exhaust unit 150 is preferably connected to the main chamber 161, and more preferably the exhaust unit 150 is disposed in the main chamber 161 and the sub chamber 162. The airtight container 160 is not particularly limited to this, and may not be separated into the main chamber 161 and the sub chamber 162, for example.

  The main chamber 161 has a powder filling unit 120, a heating unit 130, a sealing unit 140, a reflecting mirror 171, and an irradiation and light receiving device 172 disposed therein. The sub chamber 162 has the powder supply unit 110 disposed therein.

  The main chamber 161 preferably has a volume capable of accommodating a plurality of metal tubes 12 therein, and preferably has a volume capable of batch processing three to ten metal tubes 12, for example. By setting the main chamber 161 to a volume that can accommodate two or more metal tubes 12, it is not necessary to take out the metal tubes 12 from the main chamber 161 for each one, so that the mass productivity is excellent. By making the main chamber 161 a volume that can accommodate three or more metal pipes 12, it is more excellent in mass productivity. By setting the main chamber 161 to a volume that can accommodate ten or less metal tubes 12, the hermetic container 160 does not become too large.

  The main chamber 161 is larger than the volume of the sub chamber 162, and preferably has a volume that is two to three times that of the sub chamber 162. By reducing the volume of the sub chamber 162, it is advantageous in terms of time and cost when the pressure inside the sub chamber 162 is lowered and when the pressure is released to the atmosphere.

  The opening / closing member 163 is a member that separates the main chamber 161 and the sub chamber 162. As the opening / closing member 163, for example, a gate valve can be used.

  Note that the oxide superconductor raw material powder filling apparatus 100 may further include other members. For example, a gas supply unit 180 for supplying oxygen gas into the hermetic container 160, a loader (not shown) for moving between the powder filling unit 120, the heating unit 130, and the sealing unit 140, or raw material powder 11, a metal tube 12, a member (not shown) for carrying a sealed metal tube (element wire 10) or the like from the outside or the outside.

  When the oxide superconductor raw material powder filling apparatus 100 includes the gas supply unit 180, the gas supply unit 180 is configured to supply oxygen gas at a flow rate in the range of 1 ml / min to 100 ml / min. Can be supplied inside. In this case, it is preferable that the oxygen partial pressure inside the hermetic container 160 is supplied in an atmosphere of 1 Pa to 100 Pa, more preferably 8 Pa to 100 Pa. By setting the oxygen partial pressure to 1 Pa or more, oxygen is contained in the metal tube 12, so that the reaction from the raw material powder 11 to the oxide superconductor is performed by performing a heat treatment to be described later (Embodiment 2). Can promote. By setting it as 8 Pa or more, reaction from the raw material powder 11 to an oxide superconductor can be accelerated | stimulated more. On the other hand, it is preferable that the pressure is 100 Pa or less because the filling density of the raw material powder 11 filled in the metal tube 12 is not lowered.

  When the oxide superconductor raw material powder filling apparatus 100 includes a loader, for example, a loader with a gripping chuck can be used. The loader conveys the metal tube 12 to each position of the powder filling unit 120, the heating unit 130, and the sealing unit 140. It is preferable that two-dimensional coordinates of the horizontal position and the vertical position of the powder filling unit 120, the heating unit 130, and the sealing unit 140 are stored in the rotor with the number of pulses of the encoder, and the metal tube 12 can be automatically conveyed.

  Next, with reference to FIGS. 1-3, operation | movement of the filling apparatus 100 of the raw material powder of the oxide superconductor in embodiment is demonstrated. In Embodiment 1, for example, Bi2223 is described as an example of an oxide superconductor. FIG. 3 is a flowchart showing the operation of the oxide superconductor raw material powder filling apparatus 100 according to Embodiment 1 of the present invention.

  First, the powder preparation process (S1) which prepares the raw material powder of an oxide superconductor is implemented. The raw material powder 11 prepared in the powder preparation step (S1) is arranged in the powder supply unit 110.

  The raw material powder 11 to be prepared is preferably a raw material powder of an oxide superconductor having a composition of Bi—Pb—Sr—Ca—Cu—O, for example, and in particular, an atomic ratio of (bismuth and lead): strontium: calcium: copper. The raw material powder of an oxide superconductor containing a Bi-2223 phase, which is approximately expressed in a ratio of 2: 2: 2: 3, is optimal.

In the powder preparation step (S1), for example, when the raw material powder 11 of the Bi2223 superconductor is prepared as the oxide superconductor, the Bi-2212 phase ((BiPb) ₂ Sr ₂ Ca ₁ Cu ₂ O _Z or Bi ₂ Sr ₂ Ca ₁ Cu ₂ O _Z ) as the main phase, and the raw material powder 11 having the remaining Bi-2223 phase ((BiPb) ₂ Sr ₂ Ca ₂ Cu ₃ O _Z phase) and the non-superconducting phase is prepared. The main phase means that the raw material powder 11 contains 60% or more of the Bi-2212 phase.

  When the raw material powder 11 of the Bi2223 superconductor is prepared, Bi, Pb, Sr, Ca and Cu are used as the raw material powder 11, for example, Bi: Pb: Sr: Ca: Cu = 1.7: 0.4: 1. The raw material powders are mixed so that the composition ratio is 9: 2.0: 3.0. This is subjected to heat treatment at about 700 ° C. to 860 ° C. a plurality of times to prepare a raw material powder 11 composed of a large amount of Bi-2212 phase, a small amount of Bi-2223 phase, and a non-superconducting phase.

  In the powder preparation step (S1), it is preferable that the raw material powder 11 is heat-treated at 400 ° C. or higher and 800 ° C. or lower as necessary to remove gas or moisture contained in the raw material powder 11. For example, spray pyrolysis is a method in which sprayed droplets are introduced into a heating furnace, fine particles are nucleated and grown by evaporation of the solvent and chemical reaction, and then sintered and the structure and shape are adjusted (Spray Pyrolysis method) Is preferably used.

  The raw material powder 11 prepared in the powder preparation step (S1) preferably has a maximum particle size of 10 μm or less, and more preferably an average particle size of 2 μm or less. Thereby, the raw material powder 11 can be filled with the metal tube 12 with high density in a filling step (S20) described later.

  First, the apparatus preparatory process (S10) which prepares the filling apparatus 100 of the raw material powder of an oxide superconductor is implemented. Specifically, the exhaust unit 150 discharges the atmospheric gas from the inside of the hermetic container 160 to reduce the pressure inside the hermetic container 160 to 1000 Pa or less. The pressure inside the airtight container 160 is preferably 1 Pa or more and 100 Pa or less, and more preferably 8 Pa or more and 100 Pa or less. When the airtight container 160 includes the main chamber 161, the sub chamber 162, and the opening / closing member 163, the opening / closing member 163 is opened. And let the internal pressure of the main chamber 161 and the subchamber 162 be the initial force of the said range.

  And the raw material powder 11 prepared by a powder preparation process (S1) is thrown into the powder container 112, for example. Then, a predetermined amount of the raw material powder 11 is put into the supply member 111 by the control unit 113. And the raw material powder 11 inside the supply member 111 is stirred by the stirring part 114 as needed.

  Next, as shown in FIGS. 1 and 4, a filling step (S <b> 20) of filling the raw material powder 11 into the metal tube 12 at a pressure of 1000 Pa or less is performed. In the filling step (S20), as shown in FIG. 1, the powder filling unit 120 fills the metal tube 12 with the raw material powder 11 by utilizing the weight of the raw material powder 11.

  Specifically, in the filling step (S20), the robot arm 121 holds the metal tube 12. Then, the raw material powder 11 is filled into the metal tube 12 through the filling member 122. At that time, if necessary, vibration is applied to the metal tube 12 by the vibration parts 123 and 124 to suppress aggregation of the raw material powder 11 inside the metal tube 12.

  The metal tube 12 is not particularly limited as long as one of the metal tubes 12 is opened, but Ag (silver), Cu (copper), Fe (iron), Cr (chromium), Ti (titanium), Mo (molybdenum), W A metal selected from (tungsten), Pt (platinum), Pd (palladium), Rh (rhodium), Ir (iridium), Ru (ruthenium), and Os (osmium) or an alloy based on these metals It is preferable. From the viewpoint of good workability, low reactivity with the oxide superconductor, and the ability to quickly remove heat generated by the quench phenomenon, the metal tube 12 is made of silver or silver alloy having high thermal conductivity. It is preferable.

  The pressure when filling the raw material powder 11 into the metal tube 12 in the filling step (S20) is 1000 Pa or less, preferably 0.001 Pa to 900 Pa, more preferably 1 Pa to 300 Pa. The exhaust unit 150 is operated so that the inside of the airtight container 160 (or the main chamber 161 and the sub chamber 162) has a pressure within this range. When the raw material powder 11 is filled at a pressure exceeding 1000 Pa, impurity gases such as water vapor, carbon, and hydrocarbons are easily adsorbed on the raw material powder 11. By setting the pressure to 900 Pa or less, the adsorption of the impurity gas to the raw material powder 11 can be further prevented. By setting the pressure to 300 Pa or less, adsorption of impurity gas to the raw material powder 11 can be further prevented. On the other hand, it is preferable to set it as 0.001 Pa or more from a viewpoint of equipment performance. By setting it as 1 Pa or more, it is easier to adjust the pressure inside the airtight container 160.

  The filling step (S20) is preferably performed in an atmosphere containing oxygen. Specifically, the oxygen partial pressure is 1 Pa to 100 Pa, preferably 8 Pa to 100 Pa. Oxygen is supplied from the gas supply unit 180 to the inside of the hermetic container 160 (or the main chamber 161) so that the pressure is within this range. By setting the oxygen partial pressure to 1 Pa or more, oxygen is contained inside the metal tube 12, so that the raw material powder 11 is allowed to react with the oxide superconductor by performing a heat treatment to be described later (Embodiment 2). Facilitate. For example, when preparing the raw material powder 11 containing the Bi-2212 phase in the powder preparation step (S1), it is possible to promote the reaction of the Bi-2212 phase of the raw material powder 11 to the Bi-2223 phase. By setting it to 8 Pa or more, the reaction of the raw material powder 11 to the oxide superconductor can be further promoted. On the other hand, by setting it as 100 Pa or less, the packing density of the raw material powder 11 filled in the metal tube 12 is not lowered.

  The filling density of the raw material powder 11 filled in the metal tube 12 after the filling step (S20) is preferably 30% or more and 50% or less, and more preferably 33% or more and 40% or less. By filling the metal tube 12 with the raw material powder 11 under a pressure atmosphere of 1000 Pa or less in the powder filling unit 120, the air resistance can be reduced, so that only the own weight of the raw material powder 11 is used, and the filling density is within the above range. The raw material powder 11 can be filled in the metal tube 12. By setting the packing density to 30% or more, the density of the oxide superconductor can be improved in a molding process such as wire drawing or rolling described below (Embodiment 2), so that the oxide superconductor obtained by the molding process The critical current value can be further improved. For example, when preparing the raw material powder containing the Bi-2212 phase in the powder preparation step (S1), the density of the oxide superconductor having the Bi-2223 phase as the main phase can be improved. By setting the packing density to 33% or more, the density of the oxide superconductor can be further improved. On the other hand, by setting the packing density to 50% or less, the inside air permeability of the metal tube 12 is good and can be uniformly heated in the heating step (S30) described later, so that the impurity gas inside can be uniformly removed. By setting the packing density to 40% or less, the impurity gas can be more uniformly removed in the heating step (S30).

  The “filling density” means a value (%) represented by the following formula: {(weight of raw material powder 11 to be filled ÷ volume of portion filled with raw material powder 11) ÷ theoretical density} × 100. To do. The theoretical density means a density in a state where the raw material powder 11 is packed like a single crystal without gaps.

  In the measurement of the packing density, first, as shown in FIG. 2, the height H of the raw material powder 11 filled in the metal tube 12 is measured using a reflecting mirror 171, an irradiation device 172a, and a light receiving device 172b. Then, the volume of the portion filled with the raw material powder 11 can be calculated from the bottom area of the metal tube 12.

  When the raw material powder 11 is filled into the metal tube 12 at a pressure of 1000 Pa or less by the filling step (S20), the impurity concentration inside the metal tube 12 filled with the raw material powder 11 becomes 1000 ppm or less.

  Next, as shown in FIGS. 1 and 4, a heating step (S30) is performed in which the metal tube 12 filled with the raw material powder 11 is heated at a pressure of 1000 Pa or less and a temperature of 100 ° C. or higher and 800 ° C. or lower. . In the heating step (S30), as shown in FIG. 4, the heating unit 130 heats the metal tube 12 filled with the raw material powder 11. In order to arrange the periphery so as to be surrounded by the heating unit 130, the metal tube 12 filled with the raw material powder 11 is moved by, for example, a loader (not shown). Note that the heating step (S30) may be omitted.

  The pressure when filling the metal tube 12 filled with the raw material powder 11 in the heating step (S30) is 1000 Pa or less, preferably 0.001 Pa to 900 Pa, more preferably 1 Pa to 300 Pa. The exhaust unit 150 is operated so that the inside of the airtight container 160 (or the main chamber 161 and the sub chamber 162) has a pressure within this range. In addition, since the powder filling part 120 and the heating part 130 are arrange | positioned inside the airtight container 160, a filling process (S20) and a heating process (S30) are implemented under the same pressure fundamentally.

  When the heating step (S30) is performed at a pressure of 1000 Pa or less, the impurity gas adsorbed on the raw material powder 11 can be easily removed. By setting it to 900 Pa or less, the impurity gas adsorbed to the raw material powder 11 can be more easily removed. By setting the pressure to 300 Pa or less, the impurity gas adsorbed on the raw material powder 11 can be further removed. On the other hand, it is preferable to set it as 0.001 Pa or more from a viewpoint of equipment performance. By setting it as 1 Pa or more, it is easier to adjust the pressure inside the airtight container 160.

  The temperature when filling the metal tube 12 filled with the raw material powder 11 in the heating step (S30) is 100 ° C. or higher and 900 ° C. or lower, preferably 100 ° C. or higher and 800 ° C. or lower, more preferably 500 ° C. or higher and 800 ° C. or lower. preferable. By setting the temperature to 100 ° C. or higher, the impurity gas adsorbed on the raw material powder 11 filled in the metal tube 12 in the filling step (S20) can be easily removed. By setting the temperature to 500 ° C. or higher, the impurity gas adsorbed on the raw material powder 11 can be more easily removed. By setting the temperature to 900 ° C. or lower, the raw material powder 11 does not dissolve. By making it 800 degrees C or less, the raw material powder 11 becomes difficult to melt | dissolve.

  The packing density of the raw material powder 11 filled in the metal tube 12 after the heating step (S30) is the same as the packing density of the raw material powder 11 filled in the metal tube 12 after the filling step (S20). % Or more and 50% or less is preferable.

  When the metal tube 12 filled with the raw material powder 11 is heated at a temperature of 100 ° C. or more and 800 ° C. or less by the heating step (S30) at a pressure of 1000 Pa or less, the inside of the metal tube 12 filled with the raw material powder 11 The impurity concentration of is 10 ppm or less.

  Next, as shown in FIGS. 1 and 3, a sealing step (S40) for sealing the metal tube 12 filled with the raw material powder 11 at a pressure of 1000 Pa or less is performed. In the sealing step (S40), the opening at the end of the metal tube 12 is sealed with a sealing member 13, as shown in FIG.

  The pressure when the raw material powder 11 is filled in the metal tube 12 in the sealing step (S40) is 1000 Pa or less, preferably 0.001 Pa to 900 Pa, and more preferably 1 Pa to 300 Pa. The exhaust unit 150 is operated so that the inside of the airtight container 160 (or the main chamber 161 and the sub chamber 162) has a pressure within this range. In addition, since the powder filling part 120, the heating part 130, and the sealing part 140 are arrange | positioned inside the airtight container 160, a filling process (S20), a heating process (S30), and a sealing part (S40) are as follows. Basically, it is carried out under the same pressure.

  When the sealing step (S40) is performed at a pressure exceeding 1000 Pa, impurity gas is likely to be mixed into the metal tube 12 during sealing. By setting the pressure to 900 Pa or less, it is possible to further prevent the impurity gas from being mixed into the metal tube 12. By setting the pressure to 30 Pa or less, it is possible to further prevent the impurity gas from being mixed into the metal tube 12. On the other hand, it is preferable to set it as 0.001 Pa or more from a viewpoint of equipment performance. By setting it as 1 Pa or more, it is easier to adjust the pressure inside the airtight container 160.

  In the sealing step (S40), as in the filling step (S20), it is preferably performed in an atmosphere containing oxygen, and specifically, the oxygen partial pressure is preferably 1 Pa or more and 100 Pa or less.

  The temperature at which the raw material powder 11 is filled in the metal tube 12 in the sealing step (S40) is preferably 100 ° C. or higher and 800 ° C. or lower. By setting it as 100 degreeC or more, when sealing with the sealing member 13, adsorption | suction of the impurity gas to the raw material powder 11 can be prevented more. By making it 800 degrees C or less, the raw material powder 11 does not melt | dissolve.

  Further, the packing density of the raw material powder 11 filled in the metal tube 12 after the sealing step (S40) is the same as the packing density of the raw material powder 11 filled in the metal tube 12 after the filling step (S20), It is preferably 30% or more and 50% or less.

  In the sealing step (S40), the method for sealing the metal tube 12 filled with the raw material powder 11 is not particularly limited. The sealing method is preferably a joining method that can withstand the wire drawing and can be applied to vacuum encapsulation from the viewpoint of performing the wire drawing while the metal tube 12 is sealed. As a sealing method, a method such as brazing or pressure bonding of an exhaust nozzle welded to the metal tube 12 can be used in addition to the induction heating method or electron beam welding by the welded portion 141 shown in FIG.

  Specifically, the sealing member 13 disposed on the mounting table 142 is disposed on the opening of the metal tube 12. Then, a pressure is applied to the sealing member 13 by the sealing member pressing portion 143. Then, the opening of the metal tube 12 is sealed with the sealing member 13 at the welded portion 141.

  Although the sealing member 13 is not particularly limited, it is preferable to use a member made of the same material as the metal tube 12 and having a shape that can be fitted into the opening of the metal tube 12.

  By performing the above steps (S10 to S40), the raw material powder 11, the metal tube 12 filled with the raw material powder 11, and the sealing member 13 for preventing air or the like from entering the metal tube 12 are obtained. The strand 10 provided can be manufactured.

  As described above, according to the raw material powder filling apparatus 100 of the oxide superconductor in Embodiment 1 of the present invention, the airtight container 160 that can discharge the atmospheric gas at the exhaust part 150 to a pressure lower than the atmospheric pressure. Inside, the powder supply part 110, the powder filling part 120, and the sealing part 140 are arrange | positioned. Thus, the impurity gas can be reduced when the raw material powder 11 is filled in the metal tube 12 by the powder filling unit 120, and the metal tube 12 can be sealed in a state where the impurity gas is reduced by the sealing unit 140. Therefore, when the strand 10 in which the raw material powder 11 is filled in the metal tube 12 is formed into the oxide superconductor by the raw material powder filling device 100 of the oxide superconductor, the orientation disorder of the oxide superconductor due to the impurity gas is generated. Can be prevented. Therefore, an oxide superconductor capable of improving the critical current value can be obtained.

  In addition, it is particularly preferable that the atmospheric gas can be discharged from the inside of the airtight container 160 by the exhaust part 150 to reduce the pressure to 1000 Pa or less from the viewpoint of effectively preventing impurities from being mixed into the metal tube 12.

(Embodiment 2)
In the second embodiment, the raw material powder 11, the metal tube 12 filled with the raw material powder 11, and the sealing in which the metal tube 12 is sealed by the oxide superconductor raw material powder filling apparatus 100 in the first embodiment. The manufacturing method of an oxide superconducting wire is demonstrated using the strand provided with the member 13. FIG.

  FIG. 4 is a partial cross-sectional perspective view schematically showing the configuration of the oxide superconducting wire according to Embodiment 2 of the present invention. For example, a multi-core oxide superconducting wire will be described with reference to FIG. The oxide superconducting wire 20 has a plurality of oxide superconductors 21 (filaments) extending in the longitudinal direction and a sheath portion 22 covering them. The material of each of the plurality of oxide superconductors 21 is preferably, for example, a Bi—Pb—Sr—Ca—Cu—O based composition, and in particular, a material containing a Bi2223 phase is optimal. The material of the sheath portion 22 is made of a metal such as silver or a silver alloy.

  In addition, although the multi-core wire was demonstrated in the above, the oxide superconducting wire of the single core wire structure where the one oxide superconductor 21 is coat | covered with the sheath part 22 may be used.

  Next, the manufacturing method of said oxide superconducting wire is demonstrated. First, the metal tube 12 (elementary wire 10) filled with the raw material powder 11 is drawn using the raw material powder filling apparatus 100 of the oxide superconductor according to the first embodiment, and the raw material powder 11 is used as a core material. A single core wire coated with a metal such as silver is prepared. Next, many single core wires are bundled and fitted into a metal tube made of a metal such as silver. As a result, a multi-core wire having a large number of raw material powders 11 as a core is obtained.

  Next, the wire material having a multi-core structure is drawn to a desired diameter to produce a multi-core wire in which the raw material powder 11 is embedded in a sheath portion 22 such as silver. Thereby, a long multifilamentary wire having a form in which the raw material powder 11 of the oxide superconducting wire 20 is coated with a metal is obtained.

  Next, this multifilament wire is rolled into a tape-like wire. By this rolling, the density of the raw material powder 11 is further increased.

The tape-like wire rod uses the strand 10 having a high filling density and a reduced impurity gas concentration, so that the density does not occur in the above-described forming process such as wire drawing or rolling, and the oxide superconducting crystal. Next, this tape-shaped wire is heat-treated at a temperature of 400 ° C. or higher and 900 ° C. or lower, for example, at atmospheric pressure. When the raw material powder 11 is a raw material powder of the Bi2223 superconducting wire, the Bi-2212 phase of the raw material powder 11 is crystal-grown by heat treatment, and the oxide superconductivity has a superconducting crystal composed of the Bi-2223 phase as the main phase. It becomes the body 21. Since the Bi-2212 phase of the raw material powder 11 is not completely changed to the Bi-2223 phase by the heat treatment, the oxide superconductor 21 has an element ratio of (bismuth and lead): strontium: calcium: copper approximately 2: 2: 1: In some cases, a superconducting crystal composed of a Bi-2212 phase composed of 2 is included. Note that heat treatment and rolling may be applied to the tape-shaped wire several times.

  By performing the above manufacturing process, an oxide superconducting wire 20 such as a Bi2223 superconducting wire is obtained as shown in FIG. Since the oxide superconducting wire 20 is manufactured from the wire 10 that can reduce the concentration of impurity gas entering the metal tube 12, the crystal orientation of the oxide superconducting wire 20 can be improved and the critical current value can be improved. it can.

[Example]
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these.

(Examples 1 to 15)
In Examples 1 to 15 of the present invention, a raw material powder is manufactured by filling a metal tube with a raw material powder using the oxide superconductor raw material powder filling apparatus according to the first embodiment of the present invention. A Bi2223 superconducting wire was produced as an oxide superconducting wire from the wire obtained according to the method for producing an oxide superconducting wire.

  Specifically, in Examples 4, 5, and 11 to 15, the raw material powder filling device of the oxide superconductor provided with the heating unit shown in FIG. 1 is used. In Examples 1 to 3 and 6 to 10, the heating unit is used. (The heating part is not provided in FIG. 1) The raw material powder filling apparatus of the oxide superconductor was used. That is, in Examples 4, 5, and 11 to 15, the filling step (S20), the heating step (S30), and the sealing step (S40) are performed, and in Examples 1 to 3 and 6 to 10, the filling step (S20). And the sealing process (S40) was implemented and the heating process (S30) was not implemented.

Specifically, first, a raw material powder made of Bi-2212, Ca ₂ PbO ₄ , Ca ₂ CuO ₃ , (Ca, Sr) ₁₄ Cu ₂₄ O ₄₁ was prepared (powder preparation step (S1)). And the raw material powder prepared for the powder supply part was supplied.

  Next, the open / close member was opened, and the atmospheric gas was discharged from the inside of the hermetic container at the exhaust part so that the pressure in the hermetic container (main chamber and sub chamber) became the pressure described in Table 1 below ( Device preparation step (S10)). In Table 1 below, the total pressure means the pressure in the airtight container (total pressure: Pa). In Table 1, the oxygen pressure means the oxygen partial pressure in the hermetic container. The oxygen pressure (Pa) was calculated by measuring the oxygen concentration in the hermetic container with a densitometer and total pressure × concentration.

Next, a raw material powder made of Bi-2212, Ca ₂ PbO ₄ , Ca ₂ CuO ₃ , (Ca, Sr) ₁₄ Cu ₂₄ O ₄₁ was filled in a metal tube made of Ag at the pressure shown in Table 1 (filling step). (S20)).

  Next, in Examples 4, 5, and 11 to 15, the heating unit heated the metal tube filled with the raw material powder at the temperature shown in Table 1 from the outside (heating step (S30)).

  Next, the metal tube filled with the raw material powder was sealed with a sealing member made of Ag using an induction heating type weld (sealing step (S40)).

  Next, a metal tube (wire) filled with raw material powder was drawn to produce a single core wire. Next, many single core wires were bundled and fitted into a metal tube made of Ag to obtain a multi-core wire. Next, the wire having a multi-core structure was drawn and rolled into a tape-like wire. Next, heat treatment was performed at 840 ° C. for 50 hours under an oxygen concentration of 8%.

  By performing the above steps, Bi2223 superconducting wires in Examples 1 to 15 were obtained.

(Evaluation methods)
About the manufactured Bi2223 superconducting wire of Examples 1-15, the packing density, the orientation shift angle, and the critical current value were measured by the following methods. These results are shown in Table 1.

The filling density is determined by irradiating a laser with an irradiation device from above the opening of the metal tube after the filling step, reflecting the laser with a reflecting mirror, and receiving the reflected light with the light receiving device. The height filled with was measured. Then, the volume of the portion filled with the raw material powder was calculated from the measured height and the bottom area of the metal tube. Further, the weight of the raw material powder filled in the metal tube was measured. The theoretical density of the raw material powder is 6.3 g / cm ³ , and from the measured height and the weight of the raw material powder, {(the weight of the raw material powder to be filled ÷ the portion where the raw material powder is filled) Volume) ÷ theoretical density} × 100.

  The misorientation angle was (0.0.24) peak FWHM measured in the XRD rocking curve of the superconducting crystal composed of Bi-2223 phase in the oxide superconductor of the Bi2223 superconducting wire in Examples 1 to 15 manufactured. Was measured. In addition, FWHM is a value reflecting the inclination angle of the ab plane direction of the superconducting crystal composed of the Bi-2223 phase with respect to the direction in which the Bi2223 superconducting wire extends (the direction in which current flows in the Bi2223 superconducting wire), and the orientation of the superconducting crystal. It becomes an index indicating sex. It shows that the ab surface of each superconducting crystal is oriented better as the value of FWHM is smaller.

The critical current value was measured for the manufactured Bi2223 superconducting wires of Examples 1 to 15 at a temperature of 77 K and in a self-magnetic field. The critical current value was defined as an energization current value when an electric field of 10 ⁻⁶ V / cm was generated.

(Measurement result)
As shown in Table 1, the Bi2223 superconducting wires of Examples 1 to 15 were filled with the raw material powder in the metal tube at the powder filling portion with the pressure inside the airtight container set to 1000 Pa or less by the exhaust portion, so that the packing density was 30 % To 50%. Therefore, the Bi2223 crystal orientation deviation angle of the Bi2223 superconducting wires of Examples 1 to 15 was a small value of 9.0 ° or less. Moreover, the critical current value of the Bi2223 superconducting wire of Examples 1 to 15 was a large value of 142.0 A or more.

  In particular, the Bi2223 superconducting wire of Example 12 in which the filling step, the heating step, and the sealing step are performed by supplying oxygen so that the oxygen partial pressure is 1 Pa or more and 100 Pa or less in the hermetic container by the gas supply unit is oriented. The deviation angle and critical current value can be greatly improved.

  The embodiments and examples disclosed above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims.

  The oxide superconductor manufactured using the metal tube filled with the raw material powder by the filling apparatus for raw material powder of the oxide superconductor of the present invention has an impurity gas when filling and sealing the raw material in the metal tube. Can be reduced, so that the critical current value can be improved. Therefore, such oxide superconductors such as Bi2223 superconducting wires can be suitably used for superconducting equipment such as superconducting cables, superconducting transformers, superconducting current limiters, and power storage devices.

It is the schematic for demonstrating the filling apparatus of the raw material powder of the oxide superconductor in Embodiment 1 of this invention. It is the schematic which shows the apparatus which measures the height of the raw material powder with which the metal tube in Embodiment 1 of this invention was filled. It is a flowchart which shows operation | movement of the filling apparatus of the raw material powder of an oxide superconductor in Embodiment 1 of this invention. It is a fragmentary sectional perspective view which shows typically the structure of the oxide superconducting wire in Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Wire, 11 Raw material powder, 12 Metal tube, 12a Opening part, 13 Sealing member, 20 Oxide superconducting wire, 21 Oxide superconductor, 22 Sheath part, 100 Filling device of raw material powder of oxide superconductor, 110 Powder supply unit, 111 supply member, 112 powder container, 113 control unit, 114 stirring unit, 120 powder filling unit, 121 robot arm, 122 filling member, 123, 124 vibration unit, 125 metal tube support, 130 heating unit, 140 Sealing part, 141 Welding part, 142 Mounting table, 143 Sealing member pressing part, 150 Exhaust part, 160 Airtight container, 161 Main chamber, 162 Sub chamber, 163 Opening / closing member, 171 Reflecting mirror, 172 Irradiation and light receiving device, 172a Irradiation device, 172b Light receiving device, 180 gas supply unit.

Claims (8)

A powder supply unit for supplying raw material powder of the oxide superconductor;
A powder filling portion for filling the raw material powder into a metal tube having one side opened;
A sealing portion for sealing the metal tube filled with the raw material powder;
An airtight container in which the powder supply unit, the powder filling unit, and the sealing unit are disposed;
An apparatus for filling raw material powder of an oxide superconductor, comprising: an exhaust unit for discharging atmospheric gas from the inside of the hermetic container.   The apparatus for filling raw material powder of an oxide superconductor according to claim 1, further comprising a heating unit that is disposed inside the hermetic container and heats the metal tube filled with the raw material powder. The airtight container includes a main chamber and a sub chamber connected to the main chamber via an opening / closing member,
The powder supply unit is disposed inside the sub chamber,
The apparatus for filling raw material powder of an oxide superconductor according to claim 2, wherein the powder filling section, the heating section, and the sealing section are arranged inside the main chamber.   The optical non-contact measurement part which is arrange | positioned inside the said airtight container and measures the quantity of the said raw material powder with which the said metal tube was filled with the said powder filling part is further provided in any one of Claims 1-3. Raw material powder filling equipment for oxide superconductors.   The said powder supply part is a filling apparatus of the raw material powder of the oxide superconductor in any one of Claims 1-4 containing the control part which controls the quantity which supplies the said raw material powder to the said powder filling part.   The said powder supply part is a filling apparatus of the raw material powder of the oxide superconductor in any one of Claims 1-5 containing the stirring part which stirs the said raw material accommodated in an inside.   The said powder filling part is a filling apparatus of the raw material powder of the oxide superconductor in any one of Claims 1-6 containing the vibration part which applies a vibration to the said metal tube with which the said raw material powder was filled.   The oxide superconductor according to any one of claims 1 to 7, wherein the sealing portion includes a welding portion that locally heats a sealing member that seals the metal tube filled with the raw material powder. Raw material powder filling equipment.

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