JP2664444B2 - Method for producing decomposed molten composition crystal - Google Patents
Method for producing decomposed molten composition crystalInfo
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- JP2664444B2 JP2664444B2 JP63307811A JP30781188A JP2664444B2 JP 2664444 B2 JP2664444 B2 JP 2664444B2 JP 63307811 A JP63307811 A JP 63307811A JP 30781188 A JP30781188 A JP 30781188A JP 2664444 B2 JP2664444 B2 JP 2664444B2
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は、一方向凝固法による分解溶融組成結晶の製
造方法に関し、特に超伝導酸化物結晶の製造方法に関す
る。Description: TECHNICAL FIELD The present invention relates to a method for producing a decomposition-melting composition crystal by a directional solidification method, and particularly to a method for producing a superconducting oxide crystal.
従来、一方向凝固法によるチタン酸鉛（PbTiO3）の如
き一致溶融組成結晶及びその製造方法については、窒業
協会誌89巻.9号（1981年）第507頁から第516頁において
論じられており、また、一方向凝固法による2CaO・P2O5
−3CaO・P2O5の如き共晶組成結晶及びその製造方法につ
いては、窒業協会誌90巻.6号（1982年）第295頁から第3
04頁において論じられているが、融液の組成とそれから
析出する結晶の組成が異なる分解溶融組成結晶及びその
製造方法については論じられていない。Conventionally, a consistent melt composition crystal such as lead titanate (PbTiO 3 ) by a directional solidification method and a method for producing the same have been discussed in the Journal of the Nihon Jingyokai, Vol. 89, No. 89 (1981), pp. 507-516. 2CaO ・ P 2 O 5 by unidirectional solidification
For -3CaO · P 2 O 5 such eutectic composition crystals and the manufacturing method thereof,窒業societies 90 Vol .6 (1982) 3 from the 295 page
Although it is discussed on page 04, it does not discuss a decomposition-melting composition crystal in which the composition of a melt differs from the composition of a crystal precipitated therefrom and a method for producing the same.
液体窒素温度（77K）より高温で超伝導を示すYBa2Cu3
O7-Xの如き結晶は分解溶融組成であることが知られてい
る。YBa2Cu3O7-Xの単結晶の製造法については、アプラ
イド・フイジツクス・レター51巻．（９）.31（1987
年）第690頁から第691頁（Appl.Pnys.Lett.51（９）.31
（1987）pp690〜691）において論じられており、径が1m
m,厚さが0.2mmの板状の単結晶が得られている。ここで
単結晶の結晶構造は斜方晶系であり、板面に垂直な方
向、すなわち厚さ方向がＣ軸であることも報告されてい
る。このことは、YBa2Cu3O7-Xの結晶では、Ｃ軸方向の
結晶成長が遅く、a,b軸方向の結晶成長が速いことを示
している。YBa 2 Cu 3 showing superconductivity above liquid nitrogen temperature (77K)
Crystals such as O 7-X are known to have a decomposed melt composition. For a method for producing a single crystal of YBa 2 Cu 3 O 7-X , see Applied Physics Letter, vol. (9) .31 (1987
Year) pages 690 to 691 (Appl.Pnys.Lett.51 (9) .31)
(1987) pp690-691), with a diameter of 1 m
A plate-shaped single crystal having a thickness of 0.2 mm and a thickness of 0.2 mm was obtained. Here, it is also reported that the crystal structure of the single crystal is orthorhombic, and the direction perpendicular to the plate surface, that is, the thickness direction is the C axis. This indicates that in the YBa 2 Cu 3 O 7-X crystal, the crystal growth in the C-axis direction is slow, and the crystal growth in the a- and b-axis directions is fast.
一方、上記超伝導体の多結晶体は酸化物，炭酸塩等の
原料粉末を用いた焼結法によつて製造できることは一般
によく知らてれている。さらに、上記超伝導体の焼結体
を用いて線材を製造する方法については、ジヤパニーズ
・ジヤーナル・オブ・アプライド・フイジツクス 27
巻.2号（1988）第L185頁から第L187頁（Japanese Journ
al of Applied Physics.27.2.（1988）ppL185−L187）
において論じられている。On the other hand, it is generally well known that the above-mentioned polycrystalline superconductor can be produced by a sintering method using raw material powders such as oxides and carbonates. Further, regarding a method of manufacturing a wire rod using the sintered body of the above-described superconductor, see Japanese Journal of Applied Physics.
Vol.2 (1988) L185-L187 (Japanese Journ
al of Applied Physics. 27.2. (1988) ppL185-L187)
Are discussed in
また、融液から多結晶のYBa2Cu3O７−δが得られ、そ
の多結晶体では、超伝導体特性として重要な臨界電流値
Jcが非常に大きく、しかも磁場の下でもひどい劣化が生
じないことが、1988年４月５日〜９日に開催された米国
のマテリアルズ リサーチソサイアテイ主催のシンポジ
ウムでAT＆Ｔ社ベル研究所のS.Jinらによつて発表され
ている。In addition, polycrystalline YBa 2 Cu 3 O 7-δ is obtained from the melt, and the critical current value, which is important as a superconductor characteristic, is obtained in the polycrystalline body.
The fact that Jc was very large and did not undergo severe degradation even under a magnetic field was confirmed by AT & T Bell Labs at a symposium hosted by Materials Research Society of the United States on April 5-9, 1988. Published by S. Jin et al.
上記した一方向凝固法についての従来技術では、高温
超伝導体のYBa2Cu3O7-Xの如き、分解溶融組成結晶及び
その製造方法について論じられていないという問題があ
り、上記超伝導体のような材料の単結晶製造法について
の従来技術では、径が1mm厚さが0.2mm程度の小さな単結
晶しか得られないという問題があり、さらには、上記超
伝導体のような材料の焼結体からなるバルク材や線材の
製造法についての従来技術では、焼結体中に含まれる気
孔や結晶体の方位がそろつていないこと等のため超伝導
性が保持される臨界電流値が十分な大きさを持つたもの
が得られないという問題があつた。一方、融液から多結
晶体を得る従来技術では、全く具体的な製造条件が示さ
れないということ、及び報告には0.5mm程度の範囲の多
結晶体の写真が示されているだけで、得られる多結晶体
の大きさが示されておらず、線材等に適用可能な大きさ
の多結晶体を得る方法については何ら示されていないと
いう問題があつた。In the prior art about the above-mentioned unidirectional solidification method, there is a problem that, as in the high-temperature superconductor YBa 2 Cu 3 O 7-X , decomposition melting composition crystals and a method for producing the same are not discussed, The conventional technology for producing a single crystal of such a material has a problem that only a small single crystal having a diameter of about 1 mm and a thickness of about 0.2 mm can be obtained. In the conventional technology for the method of manufacturing a bulk material or a wire made of a sintered body, the critical current value at which superconductivity is maintained due to the fact that the orientations of pores and crystals contained in the sintered body are not aligned, etc. There was a problem that a ball having a sufficient size could not be obtained. On the other hand, in the prior art for obtaining a polycrystal from a melt, no specific production conditions are shown, and only a photograph of a polycrystal in a range of about 0.5 mm is shown in a report. However, there is a problem that the size of the polycrystal to be obtained is not shown, and there is no description about a method for obtaining a polycrystal having a size applicable to a wire or the like.
本発明の目的は、高温超伝導体のYBa2Cu3O7-Xの如き
分解溶融組成結晶の比較的大きな単結晶体あるいは多結
晶体の製造方法を提供することにあり、とりわけ、多結
晶体では結晶体の方位がそろつた配向性多結晶体の製造
方法を提供することにある。An object of the present invention is to provide a method for producing a relatively large single crystal or polycrystal of a decomposition-melting composition crystal such as YBa 2 Cu 3 O 7-X of a high-temperature superconductor. Another object of the present invention is to provide a method for producing an oriented polycrystal in which the orientations of crystals are uniform.
分解溶融組成結晶の一例である高温超伝導体のYBa2Cu
3O7-X系については、第２図に示す簡略な状態図が得ら
れる。第２図では、横軸が組成，縦軸が温度で、図中の
記号はその組成と温度の範囲で安定な相を示す。第２図
に示すように、超伝導性をもつYBa2Cu3O7-Xの組成を
Ａ、それよりCuOとBaOが多い組成を順次、B,C,Dと記号
付ける。Ｂの組成は包晶組成,Dの組成は共晶組成として
特徴付けられる。ＢとＤの間の組成であるＣの組成物を
その融点（Tcm）以上の温度に保つて、均一な融液（液
体）とし、しかる後、冷却させると融点（Tcm）あるい
はそれ以下の温度で、ほぼＡの組成のYBa2Cu3O7-Xの結
晶が析出する。結晶の析出によつて、固液界面の融液の
組成は、よりCuOとBaOに富む方、すなわちＤの組成の方
に近づいた融液は温度Tcmより低い温度でＡの組成よ
り、BaOとCuOに富む組成のYBa2Cu3O7-X系結晶を析出す
る。固液界面の融液の組成がＤに達すると、YBa2Cu3O
7-X系結晶のほかに、BaO及びCuO系結晶も析出するので
好ましくない。YBa 2 Cu of which is an example of incongruent melting composition crystal superconductor
For the 3 O 7-X system, the simplified phase diagram shown in FIG. 2 is obtained. In FIG. 2, the horizontal axis is the composition and the vertical axis is the temperature, and the symbols in the figure indicate phases that are stable in the range of the composition and the temperature. As shown in FIG. 2, the composition of YBa 2 Cu 3 O 7-X having superconductivity is designated as A, and the composition having more CuO and BaO than that is designated B, C, and D in this order. The composition of B is characterized as a peritectic composition and the composition of D is characterized as a eutectic composition. The composition C between B and D is maintained at a temperature equal to or higher than its melting point (Tcm) to obtain a uniform melt (liquid), and then cooled to a temperature equal to or lower than the melting point (Tcm). Then, crystals of YBa 2 Cu 3 O 7-X having a composition of almost A are precipitated. Due to the precipitation of crystals, the composition of the melt at the solid-liquid interface is more rich in CuO and BaO, that is, the melt approaching the composition of D is lower than the composition of A at a temperature lower than the temperature Tcm. A YBa 2 Cu 3 O 7-X type crystal having a composition rich in CuO is deposited. When the composition of the melt at the solid-liquid interface reaches D, YBa 2 Cu 3 O
In addition to the 7-X- based crystals, BaO and CuO-based crystals are also undesirably precipitated.
そこで、上記目的は次に示す手段により、達成され
る。Therefore, the above object is achieved by the following means.
初めに融液とする組成を目的の超伝導結晶が析出する
組成物、例えば第２図のＢとＤの間の組成であるＣの組
成物とし、Ｃの組成物の一部分もしくは全部を溶解さ
せ、Ｃの組成物を温度勾配をつけることによつて低温側
から高温側に向かつて一方向にほぼＡの組成の結晶を凝
固させる。First, the composition to be used as a melt is a composition in which a desired superconducting crystal is precipitated, for example, a composition of C which is a composition between B and D in FIG. 2, and a part or all of the composition of C is dissolved. , And C are subjected to a temperature gradient to solidify crystals having a composition of almost A in one direction from the low temperature side to the high temperature side.
Ｃの組成物の融液から結晶が析出する場合、種子結晶
が存在する場合と種子結晶が存在しない場合とでは凝固
物の微構造が異なる。When crystals precipitate from the melt of the composition C, the microstructure of the coagulated material differs between the case where seed crystals are present and the case where seed crystals are not present.
第１図に示すように、種子結晶が存在する場合には、
種子結晶上に融液からの析出結晶が形成される。この種
子結晶が１個の単結晶の場合、凝固物は単結晶体とな
り、種子結晶が多結晶体の場合、凝固物は多結晶体とな
る。種子結晶がある特定の結晶軸方向にそろつた配向性
多結晶体で、配向した結晶軸を成長方向に設置した場
合、容易に凝固物は配向性多結晶体となる。一方、種子
結晶が焼結体のような無秩序な配列をもつた多結晶体の
場合でも、次の理由により、凝固物は配向性多結晶体と
なる。結晶が成長する場合、その成長する速度がその結
晶体の結晶軸方向によつて通常異なる。そのため、第３
図に示すように、焼結体の種子結晶１上に融液４から結
晶析出か生じる場合、種子結晶のそれぞれの結晶におい
て、結晶成長速度の速い方向（優先成長方向）に先ず結
晶が成長する。この時、焼結体種子結晶１のそれぞれの
結晶の配列が無秩序であるので、結晶の優先成長する向
きも種子結晶のそれぞれの結晶において異なり、第３図
に示すように、結晶析出の初期では、凝固物の結晶配列
が無秩序である領域２が存在する。しかし、凝固すなわ
ち結晶成長がさらに進むに従い、第３図に示すように結
晶成長速度の速い方向と凝固進行方向とが一致する結晶
のみが成長を続けることができるので、その方向にそろ
つた柱状多結晶体３が得られる。超伝導体のYBa2Cu3O
7-Xの結晶は、第４図に示すような結晶構造をもち、従
来の技術の項で記したように、ａ軸あるいはｂ軸方向が
優先的に成長するので、凝固進行方向にａ軸あるいはｂ
軸がそろつた柱状多結晶体が得られる。ここで、種子結
晶の焼結体は最初に融液とするＣの組成物の下部、言い
換えれば凝固進行の反対側に接してＡの組成物を配置
し、Ｃの組成物とＡの組成物の境あるいはこの近傍の所
の温度が上記したＣの組成物の融点（Tcm）になるよう
に、そして種子結晶とするＡの組成物側では温度をより
低く、結晶成長方向とするＣの組成物側では温度をより
高くする温度勾配を形成する。As shown in FIG. 1, when seed crystals are present,
Crystals precipitated from the melt are formed on the seed crystals. When the seed crystal is one single crystal, the coagulated product is a single crystal, and when the seed crystal is a polycrystal, the coagulated product is a polycrystal. When the seed crystal is an oriented polycrystal aligned in a specific crystal axis direction and the oriented crystal axis is set in the growth direction, the solidified material easily becomes an oriented polycrystal. On the other hand, even when the seed crystal is a polycrystal having a disordered arrangement such as a sintered body, the coagulated material is an oriented polycrystal for the following reason. When a crystal grows, the growth speed is usually different depending on the crystal axis direction of the crystal. Therefore, the third
As shown in the figure, when a crystal precipitates from the melt 4 on the seed crystal 1 of the sintered body, the crystal grows first in each crystal of the seed crystal in a direction in which the crystal growth speed is fast (priority growth direction). . At this time, since the arrangement of each crystal of the sintered body seed crystal 1 is disordered, the preferential growth direction of the crystal is also different in each crystal of the seed crystal, and as shown in FIG. There is a region 2 in which the crystal arrangement of the coagulate is disordered. However, as the solidification, that is, the crystal growth further progresses, as shown in FIG. 3, only the crystals in which the direction of the higher crystal growth rate and the direction of the solidification progress can continue to grow, so that the columnar multiplied in that direction. Crystal 3 is obtained. Superconductor YBa 2 Cu 3 O
The 7-X crystal has a crystal structure as shown in FIG. 4 and, as described in the section of the prior art, grows preferentially in the a-axis or b-axis direction. Or b
A columnar polycrystal with aligned axes is obtained. Here, the sintered body of the seed crystal is formed by placing the composition of A in contact with the lower part of the composition of C to be melted first, in other words, in contact with the opposite side of the progress of solidification. The temperature at the boundary of or in the vicinity of this is set to the melting point (Tcm) of the composition C described above, and the temperature of the composition A as a seed crystal is lower, and the composition C as the crystal growth direction. On the object side, a temperature gradient is formed to increase the temperature.
一方、種子結晶が存在しない場合、融液と容器との界
面を結晶核としたりして、融液からの結晶析出が起き
る。この場合、結晶核の形成される数を制御することは
困難である。従つて、この場合容器底面ばかりでなく、
容器側面からも結晶析出が起こり、各結晶の方位がそろ
つた比較的大きな多結晶体は得られないとともに凝固物
内部に空洞ができやすい。このように空洞が生ずると超
伝導性が保たれる臨界電流値を高くすることができな
い。On the other hand, when there is no seed crystal, the interface between the melt and the container is used as a crystal nucleus, and crystal precipitation from the melt occurs. In this case, it is difficult to control the number of crystal nuclei formed. Therefore, in this case, not only the bottom of the container,
Crystal precipitation also occurs from the side of the container, so that relatively large polycrystals in which the orientations of the crystals are aligned cannot be obtained, and cavities are easily formed inside the solidified product. When such a cavity is formed, the critical current value at which superconductivity is maintained cannot be increased.
また上記した如く、Ｃの組成物の融液からＡの組成の
結晶が析出すると融液の組成はＡの結晶析出分だけCuO
が多くなる。結晶析出を長く続けて、長尺の凝固物を作
製する場合は、その組成変動の対策を行う必要がある。
そこで融液（特に結晶との界面の融液）の組成が常にＣ
となるように、Ａの結晶析出分だけＡの組成を融液中に
供給することにより、定常状態でＡの結晶を析出させる
ことができる。つまり、Ａの組成（YBa2Cu3O7-X）を析
出させるために、Ａの組成よりCuO＋BaOの成分が多いＣ
の組成を、ＢとＤとの間の組成に保つために、Ａの組成
成分を融液に供給する必要があるということである。Further, as described above, when crystals of the composition of A are precipitated from the melt of the composition of C, the composition of the melt becomes CuO by the amount of the crystal precipitation of A.
Increase. In the case of producing a long solidified product by continuing the crystal precipitation for a long time, it is necessary to take measures against the composition fluctuation.
Therefore, the composition of the melt (especially the melt at the interface with the crystal) is always C
By supplying the composition of A into the melt in an amount corresponding to the amount of the precipitated crystals of A, the crystals of A can be precipitated in a steady state. In other words, in order to precipitate the composition of A (YBa 2 Cu 3 O 7-X ), C containing more components of CuO + BaO than the composition of A
In order to keep the composition of A between B and D, it is necessary to supply the composition component of A to the melt.
その他、凝固速度，温度勾配等の製造条件は好ましい
凝固物が得られるように、適当な値が選ばれる。In addition, the production conditions such as the solidification rate and the temperature gradient are appropriately selected so as to obtain a preferable solidified product.
上記した一方向凝固法では、例えばYBa2Cu3O7-Xの如
き分解溶融組成結晶の単結晶体あるいは多結晶体が得ら
れる。そして、その方法で凝固を長時間続け、長い物を
作製することにより、線材が得られる。In the above-described directional solidification method, a single crystal or a polycrystal of a crystal having a decomposition and melting composition such as YBa 2 Cu 3 O 7-X is obtained. Then, the solidification is continued for a long time by the method to produce a long product, whereby a wire can be obtained.
上記した方法による単結晶及び多結晶体は凝固進行方
向すなち長手方向が結晶軸のａ軸あるいはｂ軸にそろつ
ている。YBa2Cu3O7-X結晶は超伝導状態では、臨界電流
値がｃ軸方向よりもａ軸方向あるいはｂ軸方向の方が20
倍程大きい。それによつて、上記方法による凝固物（バ
ルク材及び線材）では、十分大きな臨界電流値が得られ
る。In the single crystal and the polycrystal obtained by the above method, the solidification progress direction, that is, the longitudinal direction is aligned with the a-axis or the b-axis of the crystal axis. In the superconducting state, the critical current value of the YBa 2 Cu 3 O 7-X crystal is 20 more in the a-axis direction or the b-axis direction than in the c-axis direction.
About twice as large. As a result, a sufficiently large critical current value can be obtained with the solidified product (bulk material and wire material) obtained by the above method.
以下、本発明を具体的な実施例により詳細に説明す
る。Hereinafter, the present invention will be described in detail with reference to specific examples.
実施例１ YBa2Cu3O7-X（組成Ａ）,YBa2Cu3O7-X:CuO＝1:3（モル
比）（組成Ｃ）の２種類の組成となるように、99.9％の
純度のY2O3,BaCO3,及びCuOの各粉末を秤量し、メノウ乳
鉢とメノウ乳棒を用いたらいかい機で混合し、混合物を
それぞれアルミナ坩堝に入れて、900℃で空気中におい
て８時間加熱した後、それらを上記らいかい機で粉砕
し、仮焼粉末を得て、各粉砕物を約1ton/cm2の圧力で直
径約30mm,厚さ10mmの円板状にプレス成形した。Example 1 99.9% so that two kinds of compositions of YBa 2 Cu 3 O 7-X (composition A) and YBa 2 Cu 3 O 7-X : CuO = 1: 3 (molar ratio) (composition C) are obtained. Powders of Y 2 O 3 , BaCO 3 , and CuO having a purity of 5 wt. Were weighed, mixed with a trough using an agate mortar and an agate pestle, and the mixtures were respectively placed in alumina crucibles at 900 ° C. After heating for a period of time, they were pulverized with the above-mentioned grinder to obtain calcined powder, and each pulverized product was press-formed at a pressure of about 1 ton / cm 2 into a disk having a diameter of about 30 mm and a thickness of 10 mm.
第５図に示すように、プレス成形した上記各組成の円
板を内径30mm,高さ70mmの高純度アルミナ坩堝５に初め
に組成Ａの円板を１個、２番目に組成Ｃの円板を４個入
れた。次に、このアルミナ坩堝５を上部発熱体６と下部
発熱体７とを有し、それぞれの発熱体の発熱量を独立に
制御できる温度制御器を備えた電気炉体８中に設置し、
次のように熱処理を行つた。なお、アルミナ坩堝の上下
にそれぞれ上部熱電対９と下部熱電対10とを設けそれら
の箇所の温度を測定した。As shown in FIG. 5, a press-formed disk of each of the above compositions was first placed in a high-purity alumina crucible 5 having an inner diameter of 30 mm and a height of 70 mm, and one disk of the composition A and secondly a disk of the composition C Were placed. Next, the alumina crucible 5 is installed in an electric furnace 8 having an upper heating element 6 and a lower heating element 7 and having a temperature controller capable of independently controlling the amount of heat generated by each heating element,
Heat treatment was performed as follows. In addition, an upper thermocouple 9 and a lower thermocouple 10 were provided above and below the alumina crucible, respectively, and the temperatures at those locations were measured.
上部熱電対９の温度が1150℃に、下部熱電対10の温度
が950℃になるように室温から300℃/hの昇温速度で加熱
した。これらの温度に2h保持した後、それらの熱電対の
温度が５℃/hの速度で降下するように温度制御器を設定
し、その降温速度で5h降下させ、以後は電気炉の電源を
切断し、自然冷却とした冷却後、アルミナ坩堝ごとダイ
ヤモンドカツターで切断し、アルミナ坩堝内の凝固物を
取り出した。切断には潤滑剤として油を使い、切断後は
アセトンで洗浄し、その後、空気中で900℃.24hの焼成
を行い、CuOを多く含む低融点部分を流出させ、目的のY
Ba2Cu3O7-X結晶体を取り出した。取り出した結晶体（凝
固物）は径が30mm,長さが約20mmであり、その外観を第
６図に示した。焼結体の種子結晶11の近くの凝固物結晶
12の配列は無秩序であるが、凝固が進むに従つて、柱状
結晶13の配列がそろつていることが認められる。それら
の柱状結晶の長手方向に垂直な面をＸ線回折法により分
析した結果、YBa2Cu3O7-X結晶のａ面及びｂ面の回折ピ
ークがYBa2Cu3O7-X結晶の他の面より著しく強かつた。The heating was performed at a rate of 300 ° C./h from room temperature so that the temperature of the upper thermocouple 9 became 1150 ° C. and the temperature of the lower thermocouple 10 became 950 ° C. After maintaining at these temperatures for 2 hours, set the temperature controller so that the temperature of those thermocouples drops at a rate of 5 ° C / h, drop it at that rate for 5 hours, and then turn off the electric furnace Then, after cooling by natural cooling, the alumina crucible and the alumina crucible were cut with a diamond cutter, and the solidified material in the alumina crucible was taken out. Use oil as a lubricant for cutting, wash with acetone after cutting, then bake at 900 ° C for 24 hours in air, drain out the low melting point part containing a lot of CuO,
Ba 2 Cu 3 O 7-X crystal was taken out. The crystal (coagulated product) taken out had a diameter of 30 mm and a length of about 20 mm, and its appearance is shown in FIG. Solidified crystal near the seed crystal 11 of the sintered body
Although the arrangement of 12 is disordered, it is recognized that the arrangement of the columnar crystals 13 is uniform as the solidification proceeds. A longitudinal plane perpendicular to their columnar crystal was analyzed by X-ray diffractometry result, diffraction peaks of a surface and the surface b of the YBa 2 Cu 3 O 7-X crystals of YBa 2 Cu 3 O 7-X crystals Significantly stronger than other aspects.
実施例２ 実施例１と同様の方法で、プレス成形した組成Ａ及び
組成Ｃの円板を内径30mm,高さ70mmの高純度アルミナ坩
堝５に、初めに組成Ａの円板を１個、その次に組成Ｃの
円板を４個入れた。次に、第７図に示すようにこのアル
ミナ坩堝を上部発熱体６と下部発熱体７とを有し、それ
ぞれの発熱体の発熱量を独立に制御できる温度制御器を
備えた電気炉体８中に設置し、次のように熱処理を行つ
た。Example 2 In the same manner as in Example 1, press-formed disks of composition A and composition C were placed in a high-purity alumina crucible 5 having an inner diameter of 30 mm and a height of 70 mm. Next, four disks of composition C were placed. Next, as shown in FIG. 7, this alumina crucible is provided with an electric furnace body 8 having an upper heating element 6 and a lower heating element 7 and a temperature controller capable of independently controlling the heating value of each heating element. And heat-treated as follows.
上部電熱対７の温度が1200℃に、下部熱電対７の温度
が950℃になるように室温から約300℃/hの昇温速度で加
熱した、これらの温度に2h保持した後、それらの熱電対
の温度が５℃/hの速度で降下するように温度制御器を設
定し、その降温速度で7h降下させ、以後電気炉の電源を
切断し、自然冷却とした。一定速度の温度の降下ととも
に、上記組成Ａの仮焼粉末112を補給管111を通して、ア
ルミナ坩堝中に供給した。その供給量は、約7.1g/hで連
続的に供給を行つた。冷却後凝固物を実施例１と同様の
方法で取り出した。取り出した凝固物は径が30mm,長さ
が約30mmであつた。その凝固物の外観は実施例１と似て
いるが、配列のそろつた柱状結晶の部分は長くなつてい
た。それらの柱状結晶の長さ方向に垂直な面をＸ線回折
方により分析した結果、YBa2Cu3O7-X結晶のａ面及びｂ
面の回折ピークがYBa2Cu3O7-X結晶の他の面より著しく
強かつた。The temperature of the upper thermocouple 7 was set to 1200 ° C and the temperature of the lower thermocouple 7 was set to 950 ° C at a heating rate of about 300 ° C / h from room temperature. The temperature controller was set so that the temperature of the thermocouple dropped at a rate of 5 ° C./h, and the temperature was dropped at that rate for 7 hours. Thereafter, the power of the electric furnace was cut off to allow natural cooling. As the temperature dropped at a constant rate, the calcined powder 112 of the composition A was supplied into the alumina crucible through the supply tube 111. The supply rate was about 7.1 g / h, and the supply was continuous. After cooling, the solidified product was taken out in the same manner as in Example 1. The removed coagulate had a diameter of 30 mm and a length of about 30 mm. The appearance of the solidified product was similar to that of Example 1, but the aligned columnar crystals were longer. As a result of analyzing a plane perpendicular to the length direction of those columnar crystals by X-ray diffraction, the a-plane and b-plane of the YBa 2 Cu 3 O 7-X crystal were analyzed.
The diffraction peak of the plane was significantly stronger than the other planes of the YBa 2 Cu 3 O 7-X crystal.
この方法で、アルミナ坩堝をより長くし、その坩堝を
上から下に移動できるように電気炉を工夫すれば、さら
に長尺の凝固物が得られる。すなわち、これにより、超
伝導体YBa2Cu3O7-X結晶の線材化が可能である。In this method, if the alumina crucible is made longer and the electric furnace is devised so that the crucible can be moved from top to bottom, a longer solidified product can be obtained. That is, thereby, the superconductor YBa 2 Cu 3 O 7-X crystal can be made into a wire rod.
実施例３ 実施例１と同様の方法で、組成Ｃの仮焼粉末円板を形
成した後、底の中心部に0.5mmφの穴のある高純度アル
ミナ坩堝13に、第８図に示すように４個入れた。このア
ルミナ坩堝は内径が30mm,高さが70mmである。次に、内
径が40mm,高さが50mmの高純度アルミナ坩堝14の底の中
心部に従来例の方法であるフラツクス法により作製した
径1mm程度，厚さ0.2mm程度の広い面がｃ面であるYBa2Cu
3O7-X単結晶体15を置き、この単結晶体15の上に、前記
アルミナ坩堝13の底部の穴が位置するように、そのアル
ミナ坩堝13を設置し、それら２個のアルミナ坩堝の位置
がずれないようにしながら、実施例２と同様な電気炉中
に設置した。坩堝上下の温度，熱処理条件，組成Ａの仮
焼粉末の供給方法，凝固物等の取り出し方法等は実施例
２と同様に行つた。取り出した凝固物は、径が30mm,高
さが10mm程度の粗大な単結晶状であつた。ここで、Ｘ線
回折分析の結果、凝固進行方向はｃ軸であつた。これは
種子結晶の単結晶にｃ面が広い面である板状結晶を用い
たためで、種子結晶の単結晶にａ面あるいはｂ面が広い
面である板状結晶を用いれば、得られる単結晶は凝固進
行方向がａ軸あるいはｂ軸になる。Example 3 A calcined powder disk of composition C was formed in the same manner as in Example 1, and then placed in a high-purity alumina crucible 13 having a hole of 0.5 mmφ at the bottom center, as shown in FIG. I put four. This alumina crucible has an inner diameter of 30 mm and a height of 70 mm. Next, at the center of the bottom of the high-purity alumina crucible 14 having an inner diameter of 40 mm and a height of 50 mm, a large surface having a diameter of about 1 mm and a thickness of about 0.2 mm formed by a conventional flux method is a c-plane. A certain YBa 2 Cu
The 3 O 7-X single crystal 15 is placed, and the alumina crucible 13 is placed on the single crystal 15 so that the hole at the bottom of the alumina crucible 13 is located. It was set in the same electric furnace as in Example 2 while keeping the position. The temperature of the upper and lower portions of the crucible, the heat treatment conditions, the method of supplying the calcined powder of the composition A, and the method of removing the coagulated material were the same as in Example 2. The solidified product taken out was a coarse single crystal having a diameter of 30 mm and a height of about 10 mm. Here, as a result of the X-ray diffraction analysis, the solidification progressing direction was the c-axis. This is because a plate-shaped crystal having a wide c-plane is used as a single crystal of a seed crystal, and a single crystal obtained by using a plate-shaped crystal having a wide a-plane or a b-plane as a single crystal of a seed crystal is obtained. Indicates that the solidification progress direction is the a-axis or the b-axis.
実施例４ 実施例１と同様の方法で、第９図に示すようにプレス
成形した組成Ａ及び組成Ｃの円板を内径30mm,高さ70mm
の高純度アルミナ坩堝16に、初めに組成Ａの円板を１個
その次に組成Ｃの円板を４個入れた。次に底の中心部に
0.1mmφの穴のある外形20mm,内径16mm,高さ70mmの小さ
な高純度アルミナ坩堝17を前記アルミナ坩堝16中に挿入
した。後者の小さなアルミナ坩堝17中には、実施例１と
同様の方法で作製した直径が16mm,厚さが10mmの円板状
にプレス成形した組成Ｃの円板を５個入れた。次にこれ
らのアルミナ坩堝を実施例１と同様に上部発熱体と下部
発熱体とを有し、それぞれの発熱体の発熱量を独立に制
御できる温度制御器を備えた電気炉体中に設置し、次の
ように熱処理を行つた。Example 4 In the same manner as in Example 1, discs of composition A and composition C, which were press-formed as shown in FIG.
First, one disk of the composition A and then four disks of the composition C were placed in the high-purity alumina crucible 16 of the above. Then in the center of the bottom
A small high-purity alumina crucible 17 having an outer diameter of 20 mm, an inner diameter of 16 mm, and a height of 70 mm having a hole of 0.1 mmφ was inserted into the alumina crucible 16. In the latter small alumina crucible 17, five discs of composition C, which were press-formed into discs having a diameter of 16 mm and a thickness of 10 mm, which were produced in the same manner as in Example 1, were placed. Next, these alumina crucibles were placed in an electric furnace having a heating element having an upper heating element and a lower heating element in the same manner as in Example 1, and having a temperature controller capable of independently controlling the heating value of each heating element. The heat treatment was performed as follows.
上部熱電対の温度が1200℃に、下部熱電対の温度が95
0℃になるように室温から焼300℃/hの昇温速度で加熱し
た。これらの温度に2h保持した後、これらの熱電対の温
度が５℃/hの速度で降下するように温度制御器を設定
し、その降温速度で7h降下させ、以後は電気炉の電源を
切断し、自然冷却とした。冷却後、凝固物を実施例１と
同様の方法で取り出した。取り出した凝固物は前者の坩
堝中の物が実施例１の場合と同様であり、後者の小さな
坩堝中の物は径が16mm,高さが20mm程度の粗大な単結晶
状であつた。この粗大な単結晶状物をＸ線回折分析で調
べた結果、高さ方向（凝固進行方向）はａ軸であつた。
小さな坩堝中の凝固物が単結晶状になるのは、第10図に
示す凝固途中のアルミナ坩堝中の状態からわかるように
上部の小さなアルミナ坩堝の底部の穴は径が0.1mmであ
り、下部の柱状結晶の径は0.4mm程度であるので、下部
の柱状結晶の１個だけが、上部のアルミナ坩堝の底部を
通つて成長でき、それが種子結晶として働き、上部の小
さなアルミナ坩堝内の凝固物は単結晶となる。種子結晶
となる柱状結晶は凝固進行方向がａ軸となつていたた
め、得られた単結晶も凝固進行方向がａ軸となつた。The upper thermocouple temperature reaches 1200 ° C and the lower thermocouple temperature reaches 95 ° C.
Heating was performed from room temperature to 300 ° C./h so that the temperature became 0 ° C. After maintaining at these temperatures for 2 hours, set the temperature controller so that the temperature of these thermocouples drops at a rate of 5 ° C / h, drop the temperature at that rate for 7 hours, and then turn off the electric furnace And natural cooling. After cooling, the solidified product was taken out in the same manner as in Example 1. The solidified product taken out was the same as that in Example 1 in the former crucible, and the one in the latter small crucible was a coarse single crystal having a diameter of 16 mm and a height of about 20 mm. As a result of examining the coarse single crystal by X-ray diffraction analysis, the height direction (solidification progressing direction) was the a-axis.
The solidified material in the small crucible becomes single-crystal because the hole at the bottom of the small alumina crucible at the top is 0.1 mm in diameter and at the bottom at the bottom as can be seen from the state in the alumina crucible during solidification shown in FIG. Since the diameter of the columnar crystals is about 0.4 mm, only one of the lower columnar crystals can grow through the bottom of the upper alumina crucible, which acts as a seed crystal, and solidifies in the small alumina crucible above. The object becomes a single crystal. Since the solidification progress direction of the columnar crystal as the seed crystal was the a-axis, the solidification progress direction of the obtained single crystal was also the a-axis.
上記各実施例により製造される超伝導体結晶体は、送
電装置，電磁浮上・駆動移動体装置，医療診断装置，エ
ネルギ貯蔵装置等，様々な応用が可能である。The superconductor crystal manufactured by each of the above embodiments can be applied to various applications, such as a power transmission device, an electromagnetic levitation / drive moving device, a medical diagnostic device, and an energy storage device.
本発明によれば、高温超伝導体のYBa2Cu3O7-Xの如き
分解溶融組成結晶の単結晶体あるいは多結晶体が製造で
き、とりわけ大きな単結晶体や結晶体の方位がそろつた
配向性多結晶体が製造できる。それらの単結晶や多結晶
体では臨界電流値が大きいａ軸またはｂ軸に配向してい
るので、十分大きな臨界電流値が得られる効果がある。According to the present invention, it is possible to produce a single crystal or a polycrystal of a decomposition melt composition crystal such as a high-temperature superconductor YBa 2 Cu 3 O 7-X , and particularly, the orientation of a large single crystal or a crystal is aligned. An oriented polycrystal can be produced. These single crystals and polycrystals are oriented along the a-axis or the b-axis where the critical current value is large, so that there is an effect that a sufficiently large critical current value can be obtained.
第１図は本発明を説明するためのモデル図、第２図は超
伝導体YBa2Cu3O7-X系の状態図、第３図は配向した柱状
結晶が得られることの説明図、第４図はYBa2Cu3O7-X結
晶の構造と結晶軸方向を示すモデル図、第５図は本発明
の実施例における電気炉断面図、第６図は凝固物断面
図、第７図は本発明の実施例における電気炉断面図、第
８図及び第９図は本発明の実施例の坩堝断面図、第10図
は凝固進行途中の状態説明図、である。 符号の説明 １……焼結体種子結晶、２……無秩序配列多結晶体、３
……配向性柱状結晶、４……融液、５……坩堝、６……
上部発熱体、７……下部発熱体、８……電気炉体、９…
…上部熱電対、10……下部熱電対、11……補給管、12…
…YBa2Cu3O7-X（組成Ａ）の仮焼粉末、13……穴あき坩
堝、14……坩堝、15……単結晶体、16……坩堝、17……
穴あき坩堝、18……管、19……融液と結晶混在部、20…
…焼結体FIG. 1 is a model diagram for explaining the present invention, FIG. 2 is a phase diagram of a superconductor YBa 2 Cu 3 O 7-X system, FIG. 3 is an explanatory diagram showing that an oriented columnar crystal can be obtained, FIG. 4 is a model diagram showing a structure and a crystal axis direction of a YBa 2 Cu 3 O 7-X crystal, FIG. 5 is a sectional view of an electric furnace in an embodiment of the present invention, FIG. FIG. 8 is a sectional view of an electric furnace according to an embodiment of the present invention, FIGS. 8 and 9 are sectional views of a crucible according to an embodiment of the present invention, and FIG. DESCRIPTION OF SYMBOLS 1 ... Sintered seed crystal 2 ... Disordered polycrystal 3
... Oriented columnar crystals, 4 ... melt, 5 ... crucible, 6 ...
Upper heating element 7 Lower heating element 8 Electric furnace body 9
... upper thermocouple, 10 ... lower thermocouple, 11 ... supply pipe, 12 ...
… Calcined powder of YBa 2 Cu 3 O 7-X (composition A), 13… perforated crucible, 14… crucible, 15… single crystal, 16… crucible, 17…
Perforated crucible, 18 ... Tube, 19 ... Melt and crystal mixed part, 20 ...
… Sintered body
───────────────────────────────────────────────────── フロントページの続き (56)参考文献 特開 平２−275776（ＪＰ，Ａ) 特開 昭61−106496（ＪＰ，Ａ) Ｊａｐａｎｅｓｅ Ｊｏｕｒｎａｌ ｏｆ Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃ ｓ，1988年６月，Ｖｏｌ．27，Ｎｏ. ６，ｐ．Ｌ1065−1067 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-275776 (JP, A) JP-A-61-106496 (JP, A) Japanese Journal of Applied Physics, June 1988, Vol. 27, No. 6, p. L1065-1067
Claims (4)
おいて、 前記分解溶融組成の結晶のみを初晶として晶出する組成
の融液の下端に所望の種子結晶を配置し、 前記融液と種子結晶との境あるいはその近傍は前記分解
溶融組成の結晶の融点となり、前記融液の上端は該融点
より高温になるように温度制御し、しかる後、種子結晶
を出発点として、一方向に所望の結晶を析出させつつ、 前記所望結晶の析出した量に相当する、該所望結晶の組
成の粉体を前記融液に加えることを特徴とする分解溶融
組成結晶体の製造方法。1. A method for producing a desired crystal having a decomposed / melted composition, comprising: disposing a desired seed crystal at a lower end of a melt having a composition for crystallizing only the crystal having the decomposed / melted composition as a primary crystal; The boundary with or near the seed crystal is the melting point of the crystal of the decomposed and melted composition, and the upper end of the melt is temperature-controlled so as to be higher than the melting point. A method for producing a decomposed and melted composition crystal, comprising adding a powder having a desired crystal composition corresponding to the amount of the desired crystal precipitated to the melt while precipitating the desired crystal.
融組成結晶体の製造方法。2. The method according to claim 1, wherein the desired crystal is a superconductor.
解溶融組成結晶体の製造方法。3. The method according to claim 2, wherein the desired crystal is YBa 2 Cu 2 O 7-X .
特徴とする分解溶融組成結晶体の製造方法。4. The method according to claim 3, wherein the melt has a composition obtained by adding CuO to YBa 2 Cu 2 O 7-X .
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63307811A JP2664444B2 (en) | 1988-12-07 | 1988-12-07 | Method for producing decomposed molten composition crystal |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63307811A JP2664444B2 (en) | 1988-12-07 | 1988-12-07 | Method for producing decomposed molten composition crystal |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH02153891A JPH02153891A (en) | 1990-06-13 |
| JP2664444B2 true JP2664444B2 (en) | 1997-10-15 |
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| DE10124423A1 (en) * | 2001-05-18 | 2003-01-02 | Schott Glas | Growing oriented single crystals with reusable crystal seeds |
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| JPS63136488A (en) * | 1986-11-27 | 1988-06-08 | 松下電器産業株式会社 | Hot plate for induction heating cooker |
| JP2822451B2 (en) * | 1988-06-02 | 1998-11-11 | 住友電気工業株式会社 | Superconductor manufacturing method |
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| Title |
|---|
| Ｊａｐａｎｅｓｅ Ｊｏｕｒｎａｌ ｏｆ Ａｐｐｌｉｅｄ Ｐｈｙｓｉｃｓ，１９８８年６月，Ｖｏｌ．２７，Ｎｏ．６，ｐ．Ｌ１０６５−１０６７ |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH02153891A (en) | 1990-06-13 |
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