JPS63310763A - Production of superconductor - Google Patents
Production of superconductorInfo
- Publication number
- JPS63310763A JPS63310763A JP62144924A JP14492487A JPS63310763A JP S63310763 A JPS63310763 A JP S63310763A JP 62144924 A JP62144924 A JP 62144924A JP 14492487 A JP14492487 A JP 14492487A JP S63310763 A JPS63310763 A JP S63310763A
- Authority
- JP
- Japan
- Prior art keywords
- powder
- impurities
- magnetic field
- superconductivity
- superconducting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002887 superconductor Substances 0.000 title claims description 20
- 238000004519 manufacturing process Methods 0.000 title claims description 5
- 239000000843 powder Substances 0.000 claims abstract description 44
- 230000005291 magnetic effect Effects 0.000 claims abstract description 19
- 230000007704 transition Effects 0.000 claims abstract description 12
- 238000000465 moulding Methods 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 2
- 239000012535 impurity Substances 0.000 abstract description 18
- 230000000694 effects Effects 0.000 abstract description 8
- 239000000463 material Substances 0.000 abstract description 4
- 238000001816 cooling Methods 0.000 abstract 1
- 239000002994 raw material Substances 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 20
- BGPVFRJUHWVFKM-UHFFFAOYSA-N N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] Chemical compound N1=C2C=CC=CC2=[N+]([O-])C1(CC1)CCC21N=C1C=CC=CC1=[N+]2[O-] BGPVFRJUHWVFKM-UHFFFAOYSA-N 0.000 description 13
- 239000007788 liquid Substances 0.000 description 10
- 229910052757 nitrogen Inorganic materials 0.000 description 10
- 239000002245 particle Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000005292 diamagnetic effect Effects 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- -1 CuO Chemical class 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03C1/00—Magnetic separation
- B03C1/02—Magnetic separation acting directly on the substance being separated
- B03C1/021—Separation using Meissner effect, i.e. deflection of superconductive particles in a magnetic field
Landscapes
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
- Powder Metallurgy (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、転移温度、臨界電流、臨界磁場の特性が優れ
た高温超伝導体の作成法に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing a high-temperature superconductor having excellent properties in terms of transition temperature, critical current, and critical magnetic field.
従来、ＹＢａｚＣｕ３０ｔ−ｘ等の高温酸化物系超伝導
体は、まず原料となるＹｚ０３．ＣｕＯ等の金属酸化物
の粉末を混合した後に、温度数百°Ｃ以上で仮焼結させ
、得られた焼結体を粉砕して粉末化し、これをプレス等
によって成型し、再度焼結を行うことによって製造され
る。この過程において、超伝導性を有する酸化物は、仮
焼結の際に、すでに形成されている。すなわち、仮焼結
体を粉砕して得られた粉体は、超伝導性を有する酸化物
と、仮焼結反応の際に余剰となった金属酸化物等の非超
伝導性の不純物との混合物となる。従って、この粉体を
成型、再焼結して得られた超伝導体は、その内部に上記
の非超伝導性不純物を含有している。Conventionally, high-temperature oxide-based superconductors such as YBazCu30t-x are first made from Yz03. After mixing powders of metal oxides such as CuO, they are pre-sintered at a temperature of several hundred degrees Celsius or higher, and the resulting sintered body is crushed into powder, which is then molded using a press or the like, and sintered again. Manufactured by doing. In this process, an oxide having superconductivity is already formed during preliminary sintering. In other words, the powder obtained by crushing the pre-sintered body is a mixture of superconducting oxides and non-superconducting impurities such as metal oxides that are surplus during the pre-sintering reaction. It becomes a mixture. Therefore, the superconductor obtained by molding and resintering this powder contains the above-mentioned non-superconducting impurities inside.
［発明が解決しようとする問題点］
このようにして成型された超伝導体は転移温度が低下す
るため、所定の温度まで冷却しても、超伝導性を示さな
い。このため、超伝導体全体としての臨界電流、臨界磁
場の大きさが減少することとなる。また、上記仮焼結粉
末中には、低温において超伝導性を示すもののその転移
温度が低下している部分も含まれている。このような部
分が成型された超伝導体に混入することによって超伝導
体の転移温度の低下が起こることとなる。[Problems to be Solved by the Invention] Since the superconductor molded in this manner has a lower transition temperature, it does not exhibit superconductivity even when cooled to a predetermined temperature. Therefore, the magnitude of the critical current and critical magnetic field of the superconductor as a whole decreases. The pre-sintered powder also contains a portion that exhibits superconductivity at low temperatures but whose transition temperature is lowered. When such a portion is mixed into the molded superconductor, the transition temperature of the superconductor is lowered.
本発明の目的は、仮焼結粉体から非超伝導性の不純物を
除くことによって高温酸化物超伝導体の臨界電流、臨界
磁場を増大させることにある。An object of the present invention is to increase the critical current and critical magnetic field of a high-temperature oxide superconductor by removing non-superconducting impurities from the pre-sintered powder.
（問題点を解決するための手段〕
本発明は、高温酸化物超伝導体の製造の際に、仮焼結粉
体中に含まれる非超伝導性不純物を、超伝導体に特有な
マイスナー効果を利用して除去することを主要な特徴と
し、仮焼結粉体から不純物を除去する工程を含む点にお
いて従来技術とは異なるものである。(Means for Solving the Problems) The present invention aims to eliminate non-superconducting impurities contained in pre-sintered powder during the production of high-temperature oxide superconductors using the Meissner effect unique to superconductors. The main feature of this method is to remove impurities from the pre-sintered powder, and this method differs from the prior art in that it includes a step of removing impurities from the temporarily sintered powder.
第１図に、本発明の第１の実施例を示す。本図において
１はジュワー瓶、２は液体窒素、３は仮焼結後粉砕した
高温超伝導体粉体、４は磁性を持たない容器、５は磁石
である。不純物除去に際しては、ジュワー瓶１を液体窒
素２で満たし、この中に、仮焼結粉体３を入れた容器４
を浸し、粉体３および容器４が液体窒素と等温になるよ
うにする。その後、容器４の上部に置かれた粉体３を少
量づつ容器４内に落下させる。この時容器４の側方に磁
石５を置き、容器４内を落下する粉体３に磁場が印加さ
れるようにする。FIG. 1 shows a first embodiment of the invention. In this figure, 1 is a dewar flask, 2 is liquid nitrogen, 3 is a high-temperature superconductor powder pulverized after preliminary sintering, 4 is a non-magnetic container, and 5 is a magnet. When removing impurities, a dewar bottle 1 is filled with liquid nitrogen 2, and a container 4 containing a temporarily sintered powder 3 is placed inside the dewar bottle 1.
so that the powder 3 and container 4 become isothermal with liquid nitrogen. Thereafter, the powder 3 placed on the top of the container 4 is dropped into the container 4 little by little. At this time, a magnet 5 is placed on the side of the container 4 so that a magnetic field is applied to the powder 3 falling inside the container 4.
一般に、超電導状態にある物質は、一定値以下の強度を
有する磁場に対して完全反磁性を示す。In general, a superconducting substance exhibits complete diamagnetic property in a magnetic field having an intensity below a certain value.
これはマイスナー効果と呼ばれ、このマイスナー効果に
よって、超伝導体は、磁力線に対して反発力を受ける。This is called the Meissner effect, and due to this Meissner effect, superconductors receive a repulsive force against magnetic lines of force.
これに対して超伝導状態にない物質では、たとえ反磁性
を示すものであっても、その程度は微弱であるため、磁
力線に対する反発力は極めて弱い。On the other hand, in materials that are not in a superconducting state, even if they exhibit diamagnetic properties, the degree of diamagnetic properties is very weak, so the repulsive force against magnetic lines of force is extremely weak.
第１図において、容器４中を落下する粉体３は落下の途
中で磁石５が形成する磁場中を通過する。In FIG. 1, powder 3 falling in a container 4 passes through a magnetic field formed by a magnet 5 during the fall.
この時粉体３の中で液体窒素温度で超伝導性を示すもの
は、この磁場通過の際に、上記のマイスナー効果によっ
て反発力を受けその落下進路が、磁石５から遠ざかる方
向に曲げられる。これに対して、液体窒素温度で超伝導
性を示さないものは、磁場の影響をほとんど受けず、は
ぼ垂直に落下する。従って、容器４の底部の、磁石５に
近い部分には超伝導性を示さない不純物から成る粉体が
集中し、磁石５から遠い部分には高純度の超伝導性粉体
が集中する。容器４の磁石５から遠い部分に落下した粉
体のみを採集して、成型および再焼結を行うことにより
、不純物を含まない超伝導体成型物の作製が可能である
。At this time, when the powder 3 exhibits superconductivity at liquid nitrogen temperature, when it passes through this magnetic field, it receives a repulsive force due to the Meissner effect described above, and its falling path is bent in a direction away from the magnet 5. On the other hand, materials that do not exhibit superconductivity at liquid nitrogen temperatures are hardly affected by the magnetic field and fall almost vertically. Therefore, powder consisting of impurities that do not exhibit superconductivity is concentrated in the bottom part of the container 4 near the magnet 5, and highly pure superconducting powder is concentrated in the part far from the magnet 5. By collecting only the powder that has fallen in the part of the container 4 that is far from the magnet 5, and performing molding and resintering, it is possible to produce a molded superconductor that does not contain impurities.
第２図に、本発明の第２の実施例を示す。１４は一様な
振動を加えることが可能な容器であり、その他の符号は
第１図と同じである。不純物除去に際しては、粉体３を
容器１４内に入れ、この粉体３が液体窒素温度まで冷却
した時点で容器１４を磁石５の側にわずかに傾けて振動
を加える。この振動により、容器１４内の粉体３に、粉
体を構成する粒子間相互の摩擦力の減少が起こる。この
ため、粉体を構成する粒子は、重力および磁石５による
磁場からの力を受けて、容器１４内で移動する。この時
、液体窒素温度で超伝導性を示す粒子は、マイスナー効
果による磁場からの反発力が重力に打ち勝って磁石５か
ら遠ざかる方向に移動する。一方、超伝導性を示さない
粒子は重力の影響によって、磁石５に近づく方向に移動
する。従って充分な時間をかけて振動を与えた後には、
容器１４の、底部の磁石５に近い側に超伝導性を持たな
い不純物が集中し、磁石５から遠い側に、不純物を含ま
ない超伝導性を有する粉体が集中する。FIG. 2 shows a second embodiment of the invention. 14 is a container capable of applying uniform vibration, and the other symbols are the same as in FIG. 1. To remove impurities, the powder 3 is placed in a container 14, and when the powder 3 has cooled down to the temperature of liquid nitrogen, the container 14 is slightly tilted toward the magnet 5 and vibrated. This vibration causes a reduction in the mutual frictional force between the particles constituting the powder in the powder 3 in the container 14. Therefore, the particles constituting the powder move within the container 14 under the force of gravity and the magnetic field of the magnet 5. At this time, the particles exhibiting superconductivity at the liquid nitrogen temperature move in a direction away from the magnet 5 because the repulsive force from the magnetic field due to the Meissner effect overcomes gravity. On the other hand, particles that do not exhibit superconductivity move in a direction closer to the magnet 5 due to the influence of gravity. Therefore, after applying vibration for a sufficient period of time,
Impurities that do not have superconductivity are concentrated on the bottom side of the container 14 near the magnet 5, and powder that does not contain impurities and has superconductivity is concentrated on the side that is far from the magnet 5.
従って、容器１４の、磁石５から遠い側に集中した超伝
導性を有する粉体を採集することにより、不純物を含ま
ない超伝導体の作製が可能である。Therefore, by collecting powder having superconductivity concentrated on the side of the container 14 far from the magnet 5, it is possible to produce a superconductor free of impurities.
上記２つの実施例は、いずれも、超伝導性粉体を液体窒
素温度（７７Ｋ）に冷却し、この温度における超伝導性
の有無によって粉体を構成する粒子を選別している。し
かし、本発明は、粉体選別の際の粉体の温度を特に限定
するものではない。In both of the above two examples, superconducting powder is cooled to liquid nitrogen temperature (77 K), and particles constituting the powder are selected depending on the presence or absence of superconductivity at this temperature. However, the present invention does not particularly limit the temperature of the powder during powder sorting.
すなわち、上記２つの実施例におけるジュワー瓶１およ
び液体窒素２に代えて、一定温度を維持することが可能
な恒温装置を設けることにより、この恒温装置の設定温
度における超伝導性の有無によって粉体選別を行う方式
も本発明の１つの実施例となる。この実施例において、
恒温装置の温度を例えば９０Ｋに設定すれば転移温度が
９０に未満の粉体成分を不純物として排除することが可
能である。このため、選別された粉体成分は転移温度９
０に以上のもののみとなり、結果として成型再焼結され
た超伝導体の転移温度を高めることができる。That is, by replacing the dewar bottle 1 and liquid nitrogen 2 in the above two embodiments with a constant temperature device capable of maintaining a constant temperature, the powder can be The method of performing the sorting is also an embodiment of the present invention. In this example,
If the temperature of the constant temperature device is set to, for example, 90K, it is possible to exclude powder components having a transition temperature of less than 90K as impurities. Therefore, the selected powder components have a transition temperature of 9
As a result, the transition temperature of the molded and resintered superconductor can be increased.
以上説明したように、本発明により、高温酸化物超伝導
体の仮焼結粉体から非超伝導性不純物の除去を容易に行
うことが可能となるため、この仮焼結粉体を成型、再焼
結して製造する超伝導成形体の転移温度、臣ｎ界電流、
臨界磁場の改善およびその品質の安定化を実現すること
ができる。As explained above, according to the present invention, it is possible to easily remove non-superconducting impurities from the pre-sintered powder of a high-temperature oxide superconductor. The transition temperature of the superconducting compact produced by resintering, the field current,
It is possible to improve the critical magnetic field and stabilize its quality.
第１図は本発明の第１の実施例を示す。 第２図は本発明の第２の実施例を示す。 １：ジュワー瓶、 ２：液体窒素、 ３：仮焼超伝導体粉体、 ４．１４：容器５：磁石 第１ 図 ！ 第久図 FIG. 1 shows a first embodiment of the invention. FIG. 2 shows a second embodiment of the invention. 1: Dewar bottle, 2: Liquid nitrogen, 3: Calcined superconductor powder, 4.14: Container 5: Magnet Figure 1 ! Figure 1
Claims (1)
体の製造法において、該粉体の温度を、その超伝導転移
温度以下として、該粉体に磁場を印加し、該磁場が及ぼ
す力の作用を受ける粉体を選択的に採集し、採集された
粉体を成型することを特徴とする超伝導体の製造法。In a method for producing a superconductor by molding a powder of a superconducting substance, the temperature of the powder is set to below its superconducting transition temperature, a magnetic field is applied to the powder, and the magnetic field is A method for producing a superconductor, characterized by selectively collecting powder that is affected by a force, and molding the collected powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62144924A JPS63310763A (en) | 1987-06-10 | 1987-06-10 | Production of superconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62144924A JPS63310763A (en) | 1987-06-10 | 1987-06-10 | Production of superconductor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS63310763A true JPS63310763A (en) | 1988-12-19 |
Family
ID=15373385
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62144924A Pending JPS63310763A (en) | 1987-06-10 | 1987-06-10 | Production of superconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS63310763A (en) |
-
1987
- 1987-06-10 JP JP62144924A patent/JPS63310763A/en active Pending
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