JPH0230617A - Production of oxide superconductor - Google Patents
Production of oxide superconductorInfo
- Publication number
- JPH0230617A JPH0230617A JP17978888A JP17978888A JPH0230617A JP H0230617 A JPH0230617 A JP H0230617A JP 17978888 A JP17978888 A JP 17978888A JP 17978888 A JP17978888 A JP 17978888A JP H0230617 A JPH0230617 A JP H0230617A
- Authority
- JP
- Japan
- Prior art keywords
- oxide
- partial pressure
- superconductor
- oxide superconductor
- oxygen partial
- 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 abstract description 44
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 5
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 24
- 229910052788 barium Inorganic materials 0.000 claims abstract description 5
- 229910052802 copper Inorganic materials 0.000 claims abstract description 5
- 229910052747 lanthanoid Inorganic materials 0.000 claims abstract description 5
- 150000002602 lanthanoids Chemical class 0.000 claims abstract description 5
- 239000000126 substance Substances 0.000 claims abstract description 5
- 229910052684 Cerium Inorganic materials 0.000 claims abstract description 4
- 239000000203 mixture Substances 0.000 claims abstract description 4
- 150000004649 carbonic acid derivatives Chemical class 0.000 claims abstract description 3
- 150000002823 nitrates Chemical class 0.000 claims abstract description 3
- 239000002994 raw material Substances 0.000 claims abstract description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 22
- 239000001301 oxygen Substances 0.000 claims description 22
- 239000010949 copper Substances 0.000 claims description 8
- 229910052727 yttrium Inorganic materials 0.000 claims description 4
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 claims description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims description 3
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 claims description 3
- 238000000034 method Methods 0.000 abstract description 9
- 239000000843 powder Substances 0.000 abstract description 6
- 229910052777 Praseodymium Inorganic materials 0.000 abstract 1
- 238000003723 Smelting Methods 0.000 abstract 1
- 239000012768 molten material Substances 0.000 abstract 1
- 238000002844 melting Methods 0.000 description 12
- 230000008018 melting Effects 0.000 description 12
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 238000010304 firing Methods 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- QPLDLSVMHZLSFG-UHFFFAOYSA-N Copper oxide Chemical compound [Cu]=O QPLDLSVMHZLSFG-UHFFFAOYSA-N 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 239000013590 bulk material Substances 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Description
【発明の詳細な説明】
［発明の利用分野］
本発明は酸化物超伝導体の高密度なバルク材の作製方法
に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for producing a high-density bulk material of an oxide superconductor.
臨界温度が液体窒素温度をしのぐ、イツトリウム（元素
記号Ｙ）および／または各ランタノイド元素（ただしセ
リウム（Ｃｅ）、プラセジウム（Ｐｒ）はのぞ＜）、バ
リウム（Ｂａ）、１ｉ（Ｃｕ）、酸素（Ｏ）からなる酸
化物超伝導体が発見されて以来、これらを線材にして、
液体窒素を冷媒として用いる超伝導線材の開発が試みら
れている。Yttrium (element symbol Y) and/or each lanthanide element (except for cerium (Ce) and praseium (Pr)), barium (Ba), 1i (Cu), and oxygen ( Since the discovery of oxide superconductors consisting of
Attempts have been made to develop superconducting wires using liquid nitrogen as a refrigerant.
しかしながら、現在行なわれている通常の焼結法では、
十分な臨界電流密度が得られなかった。その理由として
は、通常の焼結法で得られた超伝導体内には空孔が多く
、そのため超伝導電流通路の実質的な断面積が小さいた
めであるとされている。However, with the current normal sintering method,
Sufficient critical current density could not be obtained. The reason for this is said to be that there are many pores in the superconductor obtained by the normal sintering method, and therefore the substantial cross-sectional area of the superconducting current path is small.
したがって、より空孔が少ない、すなわち、理論密度に
より近い超伝導体を作製することが試みられている。Therefore, attempts are being made to create superconductors with fewer vacancies, that is, closer to the theoretical density.
一方最近、超伝導体を一度溶融させた後、再結晶化させ
ることによって、臨界電流密度が理論密度と全くおなし
超伝導体が作製された。この方法は一般に溶融法とよば
れ、その臨界電流密度が、液体窒素温度、零磁場の条件
でＩｃｍ２あたり１００００アンペアもの大きな値とな
り注目されている。On the other hand, recently, a superconductor whose critical current density was completely the same as the theoretical density was fabricated by melting the superconductor and then recrystallizing it. This method is generally called the melting method, and its critical current density is as large as 10,000 amperes per Icm2 under conditions of liquid nitrogen temperature and zero magnetic field, and has attracted attention.
しかしながら、上記超伝導体の作製は、空気中では融点
が１３００度を越えるような高温になるため、そのよう
な高温に耐えるような特別な炉やるつぼが必要であった
。そこで、超伝導体作製時の融点を下げる方法が研究さ
れている。However, when producing the superconductor, the melting point reaches a high temperature of over 1300 degrees Celsius in air, so a special furnace or crucible that can withstand such high temperatures was required. Therefore, methods of lowering the melting point during the fabrication of superconductors are being researched.
超伝導体の融点を下げる方法としては、超伝導体に酸化
銅等を過剰に加える方法が知られているがこの場合は余
った銅等が超伝導特性（特にＱ”Ａ界電流宙度）に悪い
影響を与えるため良い方法ではない。A known method of lowering the melting point of a superconductor is to add an excessive amount of copper oxide, etc. to the superconductor, but in this case, the excess copper reduces superconducting properties (especially Q''A field current dispersion). This is not a good method as it will have a negative impact on
本発明はこのような問題に鑑みて、例えば１３００度を
越えるような高温に耐える特別な炉やるつぼを必要とし
ない温度条件にて理論密度に近い高密度を有する超伝導
体を作製することを目的としてなされたものである。In view of these problems, the present invention aims to produce a superconductor having a high density close to the theoretical density under temperature conditions that do not require a special furnace or crucible that can withstand high temperatures exceeding 1,300 degrees Celsius. It was done for a purpose.
Ｃ問題を解決するための手段〕
本発明は前記の目的を達成するために、イツトリウム（
元素記号Ｙ）および／または各ランタノイド元素（セリ
ウム（Ｃｅ）、プラセジウム（Ｐｒ）を除く）とバリウ
ム（Ｂａ）、銅（Ｃｕ）および酸素（Ｏ）とからなる酸
化物超伝導体の粉末もしくはその原料である上記物質の
酸化物炭酸塩、硝酸塩等の混合物を酸素分圧を低くした
雰囲気で溶融させた後、酸素分圧を徐々にあるいは急激
に増加させることによって、上記酸化物超伝導体を固化
、結晶化させることとしたものである。Means for Solving Problem C] In order to achieve the above-mentioned object, the present invention solves the problem of yttrium (
Oxide superconductor powder or its After melting a mixture of oxide carbonates, nitrates, etc. of the above-mentioned substances as raw materials in an atmosphere with a low oxygen partial pressure, the above-mentioned oxide superconductor is made by gradually or rapidly increasing the oxygen partial pressure. It was decided to solidify and crystallize it.
即ぢ、本発明は焼成時に酸素分圧を例えば５０ｍｍＨｇ
以下に保つことによって、１０００°Ｃ以下の温度で酸
化物超伝導体を溶融させ、その後、酸素分圧を増加させ
ることによって、溶融物を結晶化させ、高密度な酸化物
超伝導体を得るというものである。That is, the present invention sets the oxygen partial pressure to, for example, 50 mmHg during firing.
Melt the oxide superconductor at a temperature below 1000°C by keeping it below and then crystallize the melt by increasing the oxygen partial pressure to obtain a dense oxide superconductor. That is what it is.
本発明人は酸化物超伝導体を色々な酸素分圧、温度で焼
成した際、低酸素雰囲気下では超伝導体の融点が低下す
ることを見出し、本発明に至ったのである。第１図に酸
化物超伝導体ＹＢａ、Ｃｕ＝○？−Ｘの酸素分圧と融点
との関係を示す。The present inventors discovered that when oxide superconductors were fired at various oxygen partial pressures and temperatures, the melting point of the superconductors decreased in a low oxygen atmosphere, leading to the present invention. Figure 1 shows oxide superconductors YBa and Cu=○? The relationship between the oxygen partial pressure and melting point of -X is shown.
一方、上記酸化物超伝導体は空気中で８５０°Ｃから１
０００″Ｃの間で形成されることが知られている。そこ
で、本発明人は酸化物超伝導体を焼成する際、雰囲気中
の酸素分圧を低くして上記超伝導体の融点を、高温に耐
える特別なるつぼや炉を必要としない温度、望ましくは
８５０’Ｃ＝１０００°Ｃの間に下げて上記超伝導体を
溶融させ、その後酸素分圧を増加させることによって、
超伝導体を結晶化させた。On the other hand, the above-mentioned oxide superconductor has a temperature of 1
It is known that the melting point of the superconductor is lowered by lowering the oxygen partial pressure in the atmosphere when firing the oxide superconductor. By melting the superconductor at a temperature that does not require special crucibles or furnaces that can withstand high temperatures, preferably between 850'C = 1000°C, and then increasing the oxygen partial pressure,
Crystallized a superconductor.
本発明の酸化物超伝導体は、イツトリウム（元素記号Ｙ
）および／または各ランタノイド元素（ただしセリウム
（Ｃｅ）、プラセジウム（Ｐｒ）はのぞく）とバリウム
（Ｂａ）、銅（Ｃｕ）および酸素（Ｏ）とからなるもの
であればなんでもよい。The oxide superconductor of the present invention is made of yttrium (element symbol Y
) and/or each lanthanoid element (excluding cerium (Ce) and praseium (Pr)), barium (Ba), copper (Cu), and oxygen (O).
以下に、実施例とともに本発明の詳細な説明をする。The present invention will be described in detail below along with examples.
「実施例１」
材料として、化学式 Ｙ Ｂ ａ ｔｃ ｕ ｚＯｑ−
ｘで表される超伝導体の粉末を用いた。この粉末を第２
図に示すような上部に細い溝（１）を掘ったアルミナ製
のるつぼにいれ、酸素分圧ｌｍｍＨｇ以下のアルゴン中
で９００°Ｃで１時間焼成し、溶融させた。アルミナ製
のるつぼの溝の大きさは、長さ２０ｍｍ、幅０．５ｍｍ
、深さ０．５ｍｍである。その後１時間に１０ｍｍＨｇ
の割合で酸素分圧を増加させた。酸素分圧が７６０ｍｍ
Ｈｇに達したら、１時間に５０°Ｃの割合で５００ ’
Ｃまで温度を下げ、５００ ’Ｃで１２時間アニールし
たあと、炉からるつぼを取り出してるつぼ内にくっつい
ている超伝導体を得た。顕微鏡観察の結果、結晶粒径は
平均１０ミクロンで結晶は平板状で、それぞれの結晶は
１つの方向にそろって成長していた。"Example 1" As a material, the chemical formula YBa tcu zOq-
A superconductor powder represented by x was used. Add this powder to the second
It was placed in an alumina crucible with a thin groove (1) dug in its upper part as shown in the figure, and fired at 900°C for 1 hour in argon with an oxygen partial pressure of 1 mmHg or less to melt it. The groove size of the alumina crucible is 20 mm long and 0.5 mm wide.
, the depth is 0.5 mm. 10mmHg for 1 hour thereafter
The oxygen partial pressure was increased at a rate of . Oxygen partial pressure is 760mm
Once Hg is reached, 500' at a rate of 50°C per hour.
After lowering the temperature to 500°C and annealing at 500'C for 12 hours, the crucible was removed from the furnace to obtain a superconductor stuck inside the crucible. As a result of microscopic observation, the crystal grain size was 10 microns on average, the crystals were plate-shaped, and each crystal grew in one direction.
この超伝導体の臨界電流密度を、液体窒素温度、零磁場
という条件で測定したところ、Ｉｃｍ”あたり１１００
０アンペアという極めて高い値が得られた。従って９０
０ ’Ｃという比較的簡単に得られる温度で臨界電流密
度の高い超伝導線材を作製することが可能となった。When the critical current density of this superconductor was measured under the conditions of liquid nitrogen temperature and zero magnetic field, it was found to be 1100 per Icm".
An extremely high value of 0 ampere was obtained. Therefore 90
It has become possible to produce a superconducting wire with a high critical current density at a relatively easily obtained temperature of 0'C.
また本実施例はＹ Ｂ ａ ｚ Ｃｕ ３０７−で表さ
れる超伝導体のみを示したが、ＬａＢａ２Ｃｕ：＋０７
−Ｘであっても同様に実施することができた。In addition, although this example showed only the superconductor represented by YB az Cu 307-, LaBa2Cu: +07
-X could be similarly implemented.
ｒ実施例２ｊ
材料は「実施例１１と同じＹ Ｂ ａ ２Ｃｕ３０７−
ｘで表される超伝導体の粉末を用いた。この粉末を第２
図に示するつぼ内に置き、酸素分圧１ ｍ ｍ Ｈｇ以
下のアルゴン中で９００°Ｃで１時間焼成し、溶融させ
た。その後、電気炉内に大気圧の酸素を導入し、その状
態を１２時間保った。その後、１時間に５０°Ｃの割合
で５００°Ｃまで温度を下げ、５００ ’Ｃで１２時間
アニールしたあと、るつぼを炉から取り出した。「実施
例１」と同様にるつぼ内にくっついている超伝導体を得
た後顕微鏡で観察した結果、結晶粒径は平均０．３ミク
ロンであった。この超伝導体の臨界電流密度を、液体窒
素温度、零磁場という条件で測定したところ、Ｉｃｍ２
あたり５０００アンペアという極めて高い値が得られた
。従って９００°Ｃという比較的簡単に得られる温度で
臨界電流温度の高い超伝導線材を作製することが可能と
なった。rExample 2j The material is "YBa 2Cu307-" which is the same as in Example 11.
A superconductor powder represented by x was used. Add this powder to the second
It was placed in the crucible shown in the figure and fired at 900°C for 1 hour in argon with an oxygen partial pressure of 1 mm Hg or less to melt it. Thereafter, atmospheric pressure oxygen was introduced into the electric furnace, and this state was maintained for 12 hours. Thereafter, the temperature was lowered to 500°C at a rate of 50°C per hour, and after annealing at 500'C for 12 hours, the crucible was taken out of the furnace. As in "Example 1", a superconductor stuck in a crucible was obtained and observed under a microscope, and the average crystal grain size was 0.3 microns. When the critical current density of this superconductor was measured under the conditions of liquid nitrogen temperature and zero magnetic field, it was found that Icm2
An extremely high value of 5000 amperes per unit was obtained. Therefore, it has become possible to produce a superconducting wire with a high critical current temperature at a relatively easily obtained temperature of 900°C.
また本実施例はＹＢａｚＣｕ、、Ｏ，−ｘで表される超
伝導体のみを示したが、ＬａＢａ２Ｃｕ３０フーにであ
っても同様に実施することができた。In addition, although this example shows only the superconductor represented by YBazCu, , O, -x, it could be implemented in the same manner even if LaBa2Cu30 is used.
本発明によれば、焼成時に酸素分圧を５０ｍｍＨｇ以下
に保つことによって、ｉ ｏ ｏ ｏ ’ｃ以下の温度
で酸化物超伝導体を溶融させ、その後、酸素分圧を増加
させることによって、溶融物を結晶化させ、高密度な酸
化物超伝導体を得ることができ、しかも上記実施例に示
したように、本発明によって得られた酸化物超伝導体は
高い臨界電流密度を有したものであり、この臨界電流密
度の値は実用上、十分な値であった。また本発明によれ
ば９００〜１０００ ’Ｃという温度は比較的簡単に得
られる温度であるため、本発明を用いることによって、
臨界電流密度が高い超伝導線材を手軽に作製することが
可能となった。According to the present invention, the oxide superconductor is melted at a temperature of io o o'c or less by keeping the oxygen partial pressure at 50 mmHg or less during firing, and then the melting is performed by increasing the oxygen partial pressure. It is possible to obtain a high-density oxide superconductor by crystallizing a substance, and as shown in the above example, the oxide superconductor obtained by the present invention has a high critical current density. This value of critical current density was a practically sufficient value. Furthermore, according to the present invention, a temperature of 900 to 1000'C is a temperature that can be obtained relatively easily, so by using the present invention,
It has become possible to easily produce superconducting wires with high critical current density.
第１図は酸化物超伝導体Ｙ Ｂ ａ ｚＣｕ ：１０７
−Ｘの酸素分圧と融点の関係（斜線部は部分溶融状態を
表す）を示す図。
第２図はアルミするつぼを示す図。Figure 1 shows the oxide superconductor YB a zCu:107
FIG. 3 is a diagram showing the relationship between the oxygen partial pressure and melting point of -X (the shaded area represents a partially melted state). Figure 2 is a diagram showing an aluminum crucible.
Claims (1)
イド元素（セリウム（Ｃｅ）、プラセジウム（Ｐｒ）を
除く）とバリウム（Ｂａ）、銅（Ｃｕ）および酸素（Ｏ
）とからなる酸化物超伝導体の粉末もしくはその原料で
ある上記物質の酸化物炭酸塩、硝酸塩等の混合物を酸素
分圧を低くした雰囲気で溶融させた後、酸素分圧を徐々
にあるいは急激に増加させることによって、上記酸化物
超伝導体を固化、結晶化させることにより理論密度に極
めて近い高密度な酸化物超伝導体を得ることを特徴とす
る酸化物超伝導体の作製方法。Yttrium (element symbol Y) and/or each lanthanoid element (excluding cerium (Ce) and prasedium (Pr)), barium (Ba), copper (Cu) and oxygen (O
), or a mixture of oxide carbonates, nitrates, etc. of the above substances, which are its raw materials, is melted in an atmosphere with a low oxygen partial pressure, and then the oxygen partial pressure is gradually or suddenly reduced. A method for producing an oxide superconductor, characterized in that a high-density oxide superconductor extremely close to the theoretical density is obtained by solidifying and crystallizing the oxide superconductor by increasing the density of the oxide superconductor.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17978888A JPH0230617A (en) | 1988-07-18 | 1988-07-18 | Production of oxide superconductor |
| US08/032,172 US5338722A (en) | 1988-07-18 | 1993-03-12 | Method of forming superconducting oxide ceramic materials having high critical densities of superconducting current |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP17978888A JPH0230617A (en) | 1988-07-18 | 1988-07-18 | Production of oxide superconductor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0230617A true JPH0230617A (en) | 1990-02-01 |
Family
ID=16071902
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP17978888A Pending JPH0230617A (en) | 1988-07-18 | 1988-07-18 | Production of oxide superconductor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0230617A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6194352B1 (en) | 1994-01-28 | 2001-02-27 | American Superconductor Corporation | Multifilament composite BSCCO oxide superconductor |
| US6284712B1 (en) | 1993-04-01 | 2001-09-04 | Alexander Otto | Processing of oxide superconductors |
-
1988
- 1988-07-18 JP JP17978888A patent/JPH0230617A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6284712B1 (en) | 1993-04-01 | 2001-09-04 | Alexander Otto | Processing of oxide superconductors |
| US6436876B1 (en) | 1993-04-01 | 2002-08-20 | American Superconductor Corporation | Processing of oxide superconductors |
| US6194352B1 (en) | 1994-01-28 | 2001-02-27 | American Superconductor Corporation | Multifilament composite BSCCO oxide superconductor |
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