JPH1059718A - Production of thallium-based superconductor - Google Patents
Production of thallium-based superconductorInfo
- Publication number
- JPH1059718A JPH1059718A JP8212444A JP21244496A JPH1059718A JP H1059718 A JPH1059718 A JP H1059718A JP 8212444 A JP8212444 A JP 8212444A JP 21244496 A JP21244496 A JP 21244496A JP H1059718 A JPH1059718 A JP H1059718A
- Authority
- JP
- Japan
- Prior art keywords
- heat treatment
- based oxide
- oxide superconductor
- producing
- diffusion
- 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.)
- Granted
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Inorganic Compounds Of Heavy Metals (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、磁気共鳴映像装置
（ＭＲＩ−ＣＴ）等の超電導マグネット線材や、超電導
送電などの導電材として有望視され、特に、液体窒素温
度（７７Ｋ）、磁界下での応用が期待され、研究開発が
すすめられているＴｌ基の高臨界温度酸化物超電導線材
の製造方法に関する。The present invention is considered to be promising as a superconducting magnet wire for a magnetic resonance imaging apparatus (MRI-CT) or a conductive material for a superconducting power transmission. Particularly, the present invention is applicable to a liquid nitrogen temperature (77K) and a magnetic field. The present invention relates to a method for producing a Tl-based high-critical-temperature oxide superconducting wire, which is expected to be applied and is being researched and developed.
【０００２】[0002]
【従来の技術】常電導状態から超電導状態に遷移する臨
界温度Ｔc が液体窒素温度（７７Ｋ）を越える値をもつ
Ｙ（イットリウム）基、Ｂｉ（ビスマス）基、Ｔｌ（タ
リウム）基、Ｈｇ（水銀）基等の酸化物超電導体が発見
されている。これらの酸化物超電導体は、液体ヘリウム
で冷却することが必要であった従来のＮｂ−ＴｉやＮｂ
3 Ｓｎ等の金属系超電導体に比較して格段に有利な冷却
条件で使用できることから、実用上極めて有望な超電導
材料として研究開発が進められている。BACKGROUND ART Y (yttrium) based on whose values the critical temperature T c of the transition from normal conducting state to the superconducting state exceeds the liquid nitrogen temperature (77K), Bi (bismuth) group, Tl (thallium) group, Hg ( Oxide superconductors such as mercury) have been discovered. These oxide superconductors have been required to be cooled by liquid helium.
Since superconducting materials can be used under significantly more advantageous cooling conditions than metal-based superconductors such as 3Sn, research and development are proceeding as superconducting materials that are extremely promising in practical use.
【０００３】ところが、酸化物超電導体は、機械的性質
が極めて脆いため、これを線材の形に加工する手法の一
例として次のような方法が行われている。すなわち、酸
化物超電導体を構成する元素を含む複数の原料粉末を仮
焼して、不要成分を除いた後に、この仮焼粉末をＡｇま
たはＡｇ合金の金属管に充填し、これをスエージング、
線引き、圧延等の方法により所望の厚さのテープに加工
し、これに熱処理を施して金属管内部の圧縮混合粉末に
焼結反応を生じさせて所望の組成をもつ酸化物超電導体
を生成させ、超電導線材を製造している。However, since the oxide superconductor has extremely brittle mechanical properties, the following method has been used as an example of a technique for processing the oxide superconductor into a wire shape. That is, after calcining a plurality of raw material powders containing elements constituting the oxide superconductor to remove unnecessary components, the calcined powder is filled in a metal tube of Ag or Ag alloy, and swaged.
It is processed into a tape of a desired thickness by a method such as drawing and rolling, and is subjected to a heat treatment to cause a sintering reaction in the compressed mixed powder inside the metal tube to generate an oxide superconductor having a desired composition. Manufactures superconducting wires.
【０００４】しかし、従来の酸化物超電導体の製造方法
では、原料粉末を完全に均一に混合することが困難なこ
とから、熱処理を施しても超電導体全体が均一な組成と
ならない問題があった。加えて、Ｔｌ基酸化物超電導体
と複合する金属基材がＡｇの場合、ＴｌとＡｇが約２９
０℃の共晶点をもつために、含まれるＴｌ量によっては
純Ａｇの融点である９６０℃よりもはるかに低い温度で
Ａｇが融解してしまい、さらにＴｌ基酸化物超電導線材
の作製を困難なものにしていた。また、Ａｇは加工性が
良好である反面、線材としての機械的強度に乏しく、実
用上、機械的強度を得るためにステンレステープ等を補
強材として用いる等の対策を講じなければならなかっ
た。[0004] However, in the conventional method for producing an oxide superconductor, it is difficult to completely and uniformly mix the raw material powders. Therefore, there has been a problem that the entire superconductor does not have a uniform composition even when heat treatment is performed. . In addition, when the metal base composite with the Tl-based oxide superconductor is Ag, Tl and Ag are about 29%.
Since it has a eutectic point of 0 ° C., depending on the amount of Tl contained therein, Ag is melted at a temperature much lower than 960 ° C., which is the melting point of pure Ag, and it is difficult to produce a Tl-based oxide superconducting wire. Was something. Although Ag has good workability, it has poor mechanical strength as a wire, and in practice, it has been necessary to take measures such as using a stainless steel tape or the like as a reinforcing material in order to obtain mechanical strength.
【０００５】[0005]
【発明が解決しようとする課題】本発明は上記事情に鑑
みてなされたもので、その目的とするところは、Ｔｌ基
酸化物超電導線材を容易に作製でき、かつ、超電導体全
体を均一な組成とすることができるＴｌ基酸化物超電導
体の製造方法を提供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to make it possible to easily produce a Tl-based oxide superconducting wire and to form a superconducting material having a uniform composition. It is an object of the present invention to provide a method for producing a Tl-based oxide superconductor.
【０００６】[0006]
【課題を解決するための手段】そこで、本発明者は、先
に本発明者が成した拡散法によるＴｌ基酸化物超電導体
の合成法（特開平６−２１９４４０号）に着目し、この
方法を改良した線材化の手法により、基材の上に、均質
で緻密なＴｌ基酸化物超電導体を生成させることができ
ることを見出だした。すなわち、請求項１の発明は、Ｎ
ｉあるいはＮｉ基合金基材の表面に、少なくともＴｌ−
Ｏの元素で構成される第１の要素と、少なくともＢａ−
Ｃａ−Ｃｕ−Ｏの元素で構成される第２の要素との拡散
熱処理によってＴｌ基酸化物超電導体を生成することを
特徴とするＴｌ基酸化物超電導体の製造方法である。Therefore, the present inventor has focused on a method of synthesizing a Tl-based oxide superconductor by a diffusion method which was previously made by the present inventor (Japanese Patent Laid-Open No. 6-219440). It has been found that a homogeneous and dense Tl-based oxide superconductor can be formed on a base material by a method of forming a wire rod which has been improved. That is, the invention of claim 1
i or at least Tl-
A first element composed of an element of O and at least Ba-
A method for producing a Tl-based oxide superconductor, which comprises producing a Tl-based oxide superconductor by diffusion heat treatment with a second element composed of a Ca-Cu-O element.
【０００７】請求項２の発明は、前記第１の要素がＴｌ
−Ｂａ−Ｃａ−Ｃｕ−Ｏの元素で構成され、その原子比
がＴｌを１として、Ｂａ：０〜１．０、Ｃａ：０〜１．
０、Ｃｕ：０〜１．０の範囲にあり、また、第２の要素
がＢａ−Ｃａ−Ｃｕ−Ｏの元素で構成され、その原子比
が、Ｂａを１としてＣａ：０．５〜３．０、Ｃｕ：０．
５〜４．０の範囲にあることを特徴とする。According to a second aspect of the present invention, the first element is Tl
-Ba-Ca-Cu-O, whose atomic ratio is set to Tl as 1, Ba: 0 to 1.0, and Ca: 0 to 1..
0, Cu: 0 to 1.0, and the second element is composed of an element of Ba—Ca—Cu—O. 0.0, Cu: 0.
It is characterized by being in the range of 5 to 4.0.
【０００８】請求項３の発明は、第１及び第２の要素の
原料が、ＴｌＦ、ＢａＦ2 、ＣａＦ2 、ＣｕＦ2 から選
択された１種または２種以上のフッ化物である。請求項
４の発明は、第１の要素が、さらにＶ2 Ｏ5 を原子比で
Ｔｌを１としてＶ：０．２〜４．０となる範囲で添加し
ている。According to a third aspect of the present invention, the raw material of the first and second elements is one or more fluorides selected from TlF, BaF 2 , CaF 2 and CuF 2 . A fourth aspect of the present invention, the first element, V further V 2 O 5 as one of Tl in an atomic ratio of: is added within an amount of 0.2 to 4.0.
【０００９】請求項５の発明は、ＮｉあるいはＮｉ基合
金の基材表面に第２の要素を被覆して予備熱処理し、さ
らにその上に第１の要素を被覆し、得られた複合体を拡
散熱処理している。According to a fifth aspect of the present invention, a second element is coated on the surface of a substrate made of Ni or a Ni-based alloy, preliminarily heat-treated, and then the first element is coated thereon. Diffusion heat treatment.
【００１０】請求項６の発明は、前記第１の要素と第２
の要素との粉末を混合して得た複合粉末を、Ｎｉあるい
はＮｉ基合金で作製されたシース材の内部に充填し、拡
散熱処理している。請求項７の発明は、拡散熱処理後
に、酸素或いは５０ mol％以上の酸素を含む雰囲気中、
３００℃ないし６５０℃の範囲で焼鈍を行っている。According to a sixth aspect of the present invention, the first element and the second element
The composite powder obtained by mixing the powders with the elements described above is filled in a sheath material made of Ni or a Ni-based alloy and subjected to diffusion heat treatment. The invention according to claim 7 is characterized in that, after the diffusion heat treatment, in an atmosphere containing oxygen or oxygen of 50 mol% or more,
Annealing is performed in the range of 300 ° C. to 650 ° C.
【００１１】[0011]
【発明の実施の形態】以下本発明を詳細に説明する。本
発明では、基材としてＮｉあるいはＮｉ基合金を用い
る。基材であるＮｉは、熱処理の際、超電導体層中に拡
散しないため、超電導特性を劣化させることはなく、さ
らに耐食性に極めて優れているため、大気中あるいは酸
素を含む雰囲気中での高温熱処理に十分耐え得る。ま
た、Ｎｉは、適当な圧延等の加工と再結晶熱処理を施す
ことにより、結晶方位のそろった立方体集合組織を呈し
やすい。この結晶配向したＮｉ基材上に生成されるＴｌ
基酸化物超電導体は、Ｎｉ基材の集合組織の影響を受け
て結晶を配向させることが期待できる。さらにＮｉある
いはＮｉ基合金は、従来、酸化物超電導線材に広く用い
られているＡｇに比べ２倍以上の機械的強度を保有して
おり、また価格もＡｇに比べ１桁低い価格であることか
ら、酸化物超電導線材の製造に必要なコストを大幅に低
減することが可能である。本発明で適用可能なＮｉ基合
金としては、ナイモニック(Nimonic) 合金、インコネル
(Inconel) 合金などが挙げられる。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, Ni or a Ni-based alloy is used as the base material. Ni, which is the base material, does not diffuse into the superconductor layer during the heat treatment, so that it does not deteriorate the superconducting properties. Further, since it is extremely excellent in corrosion resistance, it is subjected to high-temperature heat treatment in the air or in an atmosphere containing oxygen. Can withstand enough. Also, Ni is liable to exhibit a cubic texture with uniform crystal orientations by performing appropriate processing such as rolling and recrystallization heat treatment. Tl generated on this crystallographically oriented Ni substrate
The base oxide superconductor can be expected to orient the crystal under the influence of the texture of the Ni base material. Further, Ni or Ni-based alloy has mechanical strength twice or more that of Ag which has been widely used in oxide superconducting wires, and the price is one order of magnitude lower than Ag. In addition, the cost required for manufacturing the oxide superconducting wire can be significantly reduced. Ni-based alloys applicable in the present invention include Nimonic alloy, Inconel
(Inconel) alloy.
【００１２】この基材表面に第１の要素と第２の要素と
の拡散熱処理によってＴｌ基酸化物超電導体を生成す
る。第１の要素は、複合体を熱処理する際に拡散を促進
させるため、なるべく低い融点をもつことが望ましく、
少なくともＴｌ−Ｏの元素で構成される酸化物あるいは
フッ化物を用いる。この第１の要素は、Ｔｌ−Ｂａ−Ｃ
ａ−Ｃｕ−Ｏの元素で構成され、その原子比は好ましい
超電導特性を得るために、Ｔｌを１として、Ｂａ：０〜
１．０、Ｃａ：０〜１．０、Ｃｕ：０〜１．０の範囲で
あることが望ましい。第１の要素は、融点が７００℃〜
８５０℃程度であるが、Ｔｌ2 Ｏ3 と共晶系を形成する
Ｖ2 Ｏ5 を添加することにより、融点を３８５℃〜５５
０℃程度まで低下させることができる。Ｖ2 Ｏ5 は、原
子比でＴｌを１として、Ｖ：０．２〜４．０の範囲で添
加するとよい。A Tl-based oxide superconductor is formed on the surface of the substrate by a diffusion heat treatment of the first element and the second element. The first element desirably has a melting point as low as possible to promote diffusion during heat treatment of the composite,
An oxide or fluoride composed of at least an element of Tl-O is used. This first element is Tl-Ba-C
It is composed of an element of a-Cu-O, and its atomic ratio is set to 1 for Tl and 0 to Ba: 0 to obtain preferable superconducting properties.
1.0, Ca: 0 to 1.0, and Cu: 0 to 1.0 are desirable. The first element has a melting point of 700 ° C.
The melting point is about 850 ° C., but by adding V 2 O 5 which forms a eutectic system with Tl 2 O 3 , the melting point is 385 ° C. to 55 ° C.
It can be lowered to about 0 ° C. V 2 O 5 is preferably added in the range of V: 0.2 to 4.0, where Tl is 1 in atomic ratio.
【００１３】第２の要素は、複合体を拡散する際の下地
としても機能するもので、なるべく高い融点をもつこと
が望ましく、少なくともＢａ−Ｃａ−Ｃｕ−Ｏで構成さ
れる酸化物を用いる。この第２の要素のＢａ−Ｃａ−Ｃ
ｕの原子比は、好ましい超電導特性を得るために、Ｂａ
を１として、Ｃａ：０．５〜３．０、Ｃｕ：０．５〜
４．０の範囲にあることが望ましい。第２の要素は、融
点が９００℃以上である。The second element also functions as a base when diffusing the composite, and desirably has a melting point as high as possible, and uses an oxide composed of at least Ba-Ca-Cu-O. Ba-Ca-C of this second element
The atomic ratio of u is preferably Ba to obtain favorable superconducting properties.
Is set to 1, Ca: 0.5 to 3.0, Cu: 0.5 to
It is desirable to be in the range of 4.0. The second element has a melting point of 900 ° C. or higher.
【００１４】上述した第１及び第２の要素は、原料粉を
所定の組成比に混合し、ついで不要成分を除去する仮焼
を行った後、微粉末に粉砕される。なお、第１及び第２
の要素の原料として、ＴｌＦ、ＢａＦ2 、ＣａＦ2 、Ｃ
ｕＦ2 等のフッ化物を用いると、生成されるＴ１基酸化
物高温超電導体の液体窒素中における磁界下の臨界電流
特性を改善することが出来る利点がある。The above-mentioned first and second elements are obtained by mixing the raw material powders in a predetermined composition ratio, then performing calcination for removing unnecessary components, and then pulverizing into fine powders. Note that the first and second
As raw materials for the elements of TlF, BaF 2 , CaF 2 , C
The use of a fluoride such as uF 2 has the advantage that the critical current characteristics of a generated T1-based oxide high-temperature superconductor in liquid nitrogen under a magnetic field can be improved.
【００１５】本発明では、上記基材表面に第１の要素、
第２の要素を被覆し、この複合体に拡散熱処理を施して
Ｔｌ基酸化物超電導体を生成するが、その具体的な方法
として、(1) ＮｉあるいはＮｉ基合金で作製されたテー
プまたは線状の基材上に、まず、第２の要素をスプレー
法、スクリーン印刷法、スピンコート法等の手法で被覆
した後、基材との密着性を高めるための予備的熱処理を
行い、次にその表面に第１の要素を同様な手法で連続的
に被覆することにより複合テープ、線等を作製する方法
と、(2) ＮｉあるいはＮｉ基合金基材シース中に第１の
要素と第２の要素の混合粉を充填して得た複合体に、線
引き、平ロール圧延および熱処理を繰り返し、テープ、
線等を作製する方法がある。In the present invention, a first element,
The second element is coated, and the composite is subjected to a diffusion heat treatment to produce a Tl-based oxide superconductor. Specific methods include (1) a tape or wire made of Ni or a Ni-based alloy. First, the second element is coated on the substrate in the form of a spray, screen printing, spin coating, or the like, and then subjected to a preliminary heat treatment to increase the adhesion to the substrate, A method of producing a composite tape, a wire, or the like by continuously coating the first element on the surface in a similar manner; and (2) a method of forming the first element and the second element in a Ni or Ni-based alloy base sheath. The composite obtained by filling the mixed powder of the elements of the above, drawing, repeating flat roll rolling and heat treatment, tape,
There is a method for producing a wire or the like.
【００１６】そして、このようにして得たテープあるい
は線状の複合体に拡散熱処理を加えることによりＴｌ基
酸化物超電導体が得られる。拡散熱処理後に、さらに作
製されたテープ、線等を、酸素或いは５０ mol％以上の
酸素を含む雰囲気中で焼鈍を行うと、より性能の良好な
材料を提供することができる。ここで、焼鈍雰囲気を酸
素或いは５０ mol％以上の酸素を含む雰囲気とした理由
は、大気中など酸素が５０ mol％未満の雰囲気では、焼
鈍を行っても特性の改善が得られないためである。Then, a Tl-based oxide superconductor is obtained by applying a diffusion heat treatment to the tape or the linear composite thus obtained. After the diffusion heat treatment, if the produced tapes, wires, and the like are annealed in an atmosphere containing oxygen or oxygen of 50 mol% or more, a material having better performance can be provided. Here, the reason why the annealing atmosphere is an atmosphere containing oxygen or oxygen of 50 mol% or more is that, if the atmosphere contains less than 50 mol% of oxygen such as in the air, the characteristics cannot be improved even if annealing is performed. .
【００１７】[0017]
【発明の効果】以上のように、本発明は、Ｔｌ基酸化物
超電導体を低融点相の第１の要素と高融点相の第２の要
素とに分け、拡散法によりＴｌ基酸化物超電導体をＮｉ
基材上に合成する方法である。その際、Ｎｉ基材とＴｌ
基酸化物超電導層との密着性は極めて良好であり、ま
た、拡散熱処理によりＮｉがＴｌ基酸化物超電導層中に
拡散することがないので、Ｔｌ基酸化物高温超電導体固
有の超電導特性を低下させることはない。また、基材で
あるＮｉは、耐食性に極めて優れているため、大気中あ
るいは酸素を含む雰囲気中での高温熱処理に十分耐え得
る。As described above, according to the present invention, the Tl-based oxide superconductor is divided into a first element having a low melting point phase and a second element having a high melting point phase, and the Tl-based oxide superconductor is formed by a diffusion method. Ni body
This is a method of synthesizing on a substrate. At this time, Ni substrate and Tl
The adhesion to the base oxide superconducting layer is extremely good, and Ni does not diffuse into the Tl-based oxide superconducting layer by diffusion heat treatment, so that the superconductivity inherent to the Tl-based oxide high-temperature superconductor is lowered. I won't let you. Ni, which is a base material, is extremely excellent in corrosion resistance, and thus can sufficiently withstand high-temperature heat treatment in the air or in an atmosphere containing oxygen.
【００１８】また、Ｎｉは、適当な圧延等の加工と再結
晶熱処理を施すことにより、結晶方位のそろった立方体
集合組織を呈しやすい。この結晶配向したＮｉ基材上に
生成されるＴｌ基酸化物超電導体は、Ｎｉの集合組織の
影響を受けて結晶が配向することが期待できる。さらに
ＮｉあるいはＮｉ基合金は、従来、酸化物超電導線材に
広く用いられているＡｇに比べ２倍以上の機械的強度を
保有しており、また価格もＡｇに比べ１桁低い価格であ
ることから、酸化物超電導線材の製造に必要なコストを
大幅に低減することが可能である。Further, Ni is liable to exhibit a cubic texture with uniform crystal orientations by performing appropriate processing such as rolling and recrystallization heat treatment. The Tl-based oxide superconductor generated on the crystal-oriented Ni base material can be expected to be crystal-oriented under the influence of the texture of Ni. Further, Ni or Ni-based alloy has mechanical strength twice or more that of Ag which has been widely used in oxide superconducting wires, and the price is one order of magnitude lower than Ag. In addition, the cost required for manufacturing the oxide superconducting wire can be significantly reduced.
【００１９】さらに、拡散法によりＴｌ基酸化物超電導
体が生成される際、低融点成分である第１の要素にフッ
化物やＶ基酸化物を用いることで、臨界電流等の超電導
特性が改善される。第１の要素にＴｌＦ等のフッ化物を
添加した場合、生成されるＴｌ基酸化物超電導体の結晶
構造の変化により磁界特性が著しく改善されるため、７
７Ｋ、磁界下で大きい輸送電流をもつ、均質で緻密な組
織のＴｌ基酸化物超電導体をＮｉ基材上に生成させるこ
とができる。また、第１の要素にＴｌ2 Ｏ3 と共晶組成
をもつＶ2 Ｏ5 の酸化物を添加した場合は、その融点を
さらに下げることができ、これと高融点成分である第２
の要素との拡散が促進され、先に本発明者が出願した拡
散法によるＴｌ基酸化物超電導拡散層よりも、はるかに
厚いＴｌ基酸化物超電導拡散層を、熱処理条件を変える
ことなく均一にＮｉ基材上に生成させることができる。
例えば、Ｔｌ基酸化物超電導拡散層の厚さを、熱処理条
件にもよるが、約６００μｍ程度と厚くすることができ
る。また、添加したＶ基酸化物は、Ｔｌ基酸化物超電導
拡散層中に取り込まれることなく外部に押し出されるの
で、超電導相の生成を促進するものの、超電導特性を劣
化させることはない。また、超電導結晶粒の成長を促進
させて、輸送電流の障害となる結晶粒界を減少させるこ
とができる。このような効果は、Ｖ2 Ｏ5 以外にも、Ｔ
ｌ2 Ｏ3 と融点の低い共晶系を形成する酸化物を加えて
も得ることができる。Further, when a Tl-based oxide superconductor is produced by a diffusion method, the superconducting characteristics such as critical current are improved by using a fluoride or a V-based oxide as the first element which is a low melting point component. Is done. When a fluoride such as TlF is added to the first element, the magnetic field characteristics are remarkably improved due to a change in the crystal structure of the generated Tl-based oxide superconductor.
7K, a Tl-based oxide superconductor having a uniform and dense structure having a large transport current under a magnetic field can be formed on a Ni substrate. Further, when an oxide of V 2 O 5 having a eutectic composition with Tl 2 O 3 is added to the first element, the melting point can be further lowered, and the second element, which is a high melting point component, can be used.
Diffusion with the element is promoted, and the Tl-based oxide superconducting diffusion layer, which is much thicker than the Tl-based oxide superconducting diffusion layer by the diffusion method previously filed by the present inventors, can be uniformly formed without changing the heat treatment conditions. It can be produced on a Ni substrate.
For example, the thickness of the Tl-based oxide superconducting diffusion layer can be as large as about 600 μm, depending on the heat treatment conditions. Further, since the added V-based oxide is extruded to the outside without being taken into the Tl-based oxide superconducting diffusion layer, it promotes generation of a superconducting phase, but does not deteriorate superconducting characteristics. Further, the growth of the superconducting crystal grains can be promoted, and the crystal grain boundaries that hinder the transport current can be reduced. Such an effect is due to T 2 in addition to V 2 O 5
It can also be obtained by adding an oxide which forms a eutectic system having a low melting point with l 2 O 3 .
【００２０】このように、本発明によれば、複合体に拡
散熱処理を行うことにより、第１の要素の成分が第２の
要素内に拡散して反応し、ＮｉあるいはＮｉ基合金の基
材の表面に、均一で緻密な高Ｔc のＴｌ基酸化物超導電
層が厚く生成され、実用に適した酸化物高温超電導体を
提供することが出来る。As described above, according to the present invention, by performing diffusion heat treatment on the composite, the components of the first element diffuse and react in the second element, and the base material of Ni or a Ni-based alloy is formed. on the surface of, the uniform generation thick Tl group oxide ultrafine conductive layer of dense high T c, it is possible to provide an oxide high temperature superconductor suitable for practical use.
【００２１】[0021]
（実施例１）ＢａＣＯ3 、ＣａＣＯ3 、ＣｕＯの原料粉
末をＢａＣａ2 Ｃｕ2 Ｏ5 の組成となるように配合し、
９００℃で１８時間の仮焼をして、ＣＯ2 等の不要成分
を除去し、ボールミルにより数ミクロン程度の粒径まで
粉砕した。この微細な粉末に、アクリル系のバインダー
を加えてペースト状にし、高融点成分である第２の要素
を作製した。ついで、このペースト状の第２の要素を、
テープ状に平ロールで圧延加工して作製した厚さ０．１
ｍｍ、巾７ｍｍ、長さ３０ｍｍのＮｉ基材の表面に、
０．２ｍｍ程度の厚さにスクリーン印刷法で被覆した。
十分乾燥させた後に、４００℃で６時間の熱処理により
バインダーを除去し、続いて９００℃で１２時間の熱処
理を行って、第２の要素とＮｉ基材を密着させた。一
方、ＴｌＦ、ＢａＯの原料粉末をＴｌ2 ＢａＯＦ2 の組
成となるよう配合し、メノー乳鉢で十分混練して第１の
要素を作製した。この第１の要素である混合粉末をエタ
ノール中に懸濁し、スラリー状にしたものをＮｉ基材の
上に被覆した第２の要素の表面に約０．１ｍｍの厚さで
スプレー法により塗布して複合体を作製した。この複合
体を、Ｔｌ2 Ｏ3 の蒸気を含んだ大気中において、８３
０℃で２時間の拡散熱処理を行った。なお、拡散熱処理
の冷却過程において、８００℃までは毎分０．１℃の速
度でゆっくりと冷却し、その後室温までは毎分１．７℃
の速度で冷却した。さらに、酸素気流中、６００℃で１
２時間の焼鈍を行って試料を作製した。試料断面の組成
分布を電子線プローブマイクロアナライザーにより分析
したところ、基材から超電導拡散層へのＮｉの拡散は認
められなかった。試料の７７ＫにおけるＩc の磁界によ
る変化を図１の曲線１に示した。図１の曲線２は第１の
要素の原料粉末としてＴｌ2 Ｏ3 を用いた場合であっ
て、その他の試料作製条件は、曲線１と同様である。曲
線１では、ゼロ磁界下で約７０Ａの輸送電流が得られ、
曲線２の約３．５倍である。曲線２の７７Ｋにおける輸
送電流は、外部磁界の印加により急激な低下が見られる
が、曲線１においては１．５Ｔの磁界下でも、著しい輸
送電流の低下は見られない。このようにＴｌ2 Ｏ3 の代
わりにＴｌＦを用いると、７７Ｋで磁界下のＩc 特性が
大幅に改善された。 （実施例２）実施例１の基材と同様の寸法をもつナイモ
ニック合金基材と、実施例１と同様の組成をもつ第２の
要素との複合体を同様な方法で作製した。次に、Ｔｌ2
Ｏ3 とＶ2 Ｏ5 の原料粉末を、原子比でＴｌを１として
Ｖが０．６４となるよう配合し、メノー乳鉢で十分混練
して第１の要素を作製した。これを実施例１と同様な方
法でＮｉ基材の上に被覆した第２の要素の表面に塗布し
た。ついでこの複合体を、Ｔｌ2 Ｏ3 の蒸気を含んだ大
気中において、８００〜８８０℃で１０分から２時間の
拡散熱処理を行った。図２は、生成された拡散層の厚さ
と熱処理温度の関係である。第１の要素にＶ2 Ｏ5 を添
加した曲線３では、添加を行っていない曲線４と比較し
て約３倍の厚さの拡散層が生成されており、拡散が著し
く促進されている。拡散熱処理後、添加したＶは超電導
相には全く固溶せず、Ｔc は１１７Ｋを示し、Ｉc は拡
散層の厚さにほぼ比例して増加した。 （実施例３）外径１０ｍｍ、内径７ｍｍのＮｉ基材シー
ス中に、実施例１の曲線１の試料で用いた第１の要素と
第２の要素を、モル比で１：１で配合して得た混合粉を
充填して得た複合体に、溝ロール、平ロール圧延加工を
行って、幅７ｍｍ、厚さ０．３ｍｍのテープ状の複合線
材を作製した。ついでこの複合線材を、実施例１と同様
の条件で拡散熱処理を行い、さらに拡散熱処理後、酸素
中、６００℃で１２時間の焼鈍を行い、Ｔｌ基酸化物超
電導体のテープ材を作製した。このテープ材は、７７
Ｋ、ゼロ磁界で約４０ＡのＩc 値を示した。Ｎｉ基材は
加工後の熱処理により、強度の（１００）＜００１＞集
合組織をとるため、これに接するＴｌ基酸化物超電導体
層を好ましい方位に結晶成長させる上に効果があると考
えられる。(Example 1) Raw material powders of BaCO 3 , CaCO 3 , and CuO were blended to have a composition of BaCa 2 Cu 2 O 5 ,
Unnecessary components such as CO 2 were removed by calcination at 900 ° C. for 18 hours, and pulverized by a ball mill to a particle size of about several microns. An acrylic binder was added to this fine powder to form a paste, thereby producing a second element that was a high melting point component. Then, this paste-like second element is
Thickness 0.1 made by rolling into a tape shape with a flat roll
mm, width 7mm, length 30mm on the surface of Ni substrate,
It was coated to a thickness of about 0.2 mm by a screen printing method.
After sufficiently drying, the binder was removed by heat treatment at 400 ° C. for 6 hours, followed by heat treatment at 900 ° C. for 12 hours to bring the second element into close contact with the Ni substrate. On the other hand, raw materials of TlF and BaO were blended so as to have a composition of Tl 2 BaOF 2 , and kneaded sufficiently in an agate mortar to prepare a first element. This mixed powder, which is the first element, is suspended in ethanol and slurried to a thickness of about 0.1 mm and applied to the surface of the second element coated on a Ni substrate by a spray method. To produce a composite. This complex is placed in an atmosphere containing Tl 2 O 3 vapor for 83 hours.
Diffusion heat treatment was performed at 0 ° C. for 2 hours. In the cooling process of the diffusion heat treatment, the cooling is slowly performed at a rate of 0.1 ° C./min up to 800 ° C., and then 1.7 ° C./min.
Cooled at the speed. Further, at 600 ° C. in an oxygen stream,
A sample was prepared by annealing for 2 hours. When the composition distribution of the sample cross section was analyzed by an electron probe microanalyzer, no diffusion of Ni from the substrate to the superconducting diffusion layer was observed. The change due to the magnetic field of the I c at 77K samples shown in curve 1 of FIG. Curve 2 in FIG. 1 is the case where Tl 2 O 3 is used as the raw material powder of the first element, and the other sample preparation conditions are the same as curve 1. Curve 1 gives a transport current of about 70 A under zero magnetic field,
It is about 3.5 times that of curve 2. The transport current at 77 K in the curve 2 sharply decreases due to the application of an external magnetic field, but the curve 1 does not show a significant decrease in the transport current even under a magnetic field of 1.5 T. Thus, when TlF was used instead of Tl 2 O 3 , the I c characteristics under a magnetic field at 77 K were significantly improved. (Example 2) A composite of a nimonic alloy substrate having the same dimensions as the substrate of Example 1 and a second element having the same composition as that of Example 1 was produced by the same method. Next, Tl 2
The raw material powders of O 3 and V 2 O 5 were blended so that the atomic ratio of Tl was 1 and V was 0.64, and kneaded sufficiently in an agate mortar to produce a first element. This was applied to the surface of the second element coated on the Ni substrate in the same manner as in Example 1. Next, the composite was subjected to diffusion heat treatment at 800 to 880 ° C. for 10 minutes to 2 hours in an atmosphere containing Tl 2 O 3 vapor. FIG. 2 shows the relationship between the thickness of the generated diffusion layer and the heat treatment temperature. In Curve 3 in which V 2 O 5 was added to the first element, a diffusion layer having a thickness approximately three times that of Curve 4 in which V 2 O 5 was not added was generated, and the diffusion was significantly promoted. After diffusion heat treatment, V was added without any solid solution in the superconducting phase, T c represents a 117K, I c is increased substantially in proportion to the thickness of the diffusion layer. (Example 3) A first element and a second element used in the sample of curve 1 of Example 1 were mixed in a Ni base sheath having an outer diameter of 10 mm and an inner diameter of 7 mm at a molar ratio of 1: 1. The composite obtained by filling the mixed powder thus obtained was subjected to groove roll and flat roll rolling to prepare a tape-shaped composite wire having a width of 7 mm and a thickness of 0.3 mm. Next, this composite wire was subjected to a diffusion heat treatment under the same conditions as in Example 1, and after the diffusion heat treatment, annealed in oxygen at 600 ° C. for 12 hours to produce a Tl-based oxide superconductor tape material. This tape material, 77
K showed an I c value of about 40 A at zero magnetic field. Since the Ni base material has a strong (100) <001> texture by the heat treatment after processing, it is considered to be effective in growing the Tl-based oxide superconductor layer in contact with the Ni base material in a preferred orientation.
【図面の簡単な説明】[Brief description of the drawings]
【図１】実施例１の試料の、７７Ｋ、磁界下でのＩc の
変化を示す図で、曲線１は、第１の要素の原料粉として
ＴｌＦを用いたものであり、曲線２はＴｌＦを用いてい
ないものである。磁界は、電流に対し垂直かつ試料面に
対し平行な方向に印加している。[1] Example 1 of the sample, 77K, a diagram showing a change in the I c under a magnetic field, curve 1 is for using TlF as raw material powder of the first element, curve 2 TlF Is not used. The magnetic field is applied in a direction perpendicular to the current and parallel to the sample surface.
【図２】実施例２の試料の生成された拡散層の厚さと拡
散熱処理温度の関係を示す図で、曲線３は、第１の要素
にＶ2 Ｏ5 を添加したもので、曲線４（破線）はＶ2 Ｏ
5 を添加していないものである。なお、拡散熱処理時間
は各温度につき一定の２時間である。FIG. 2 is a graph showing the relationship between the thickness of a diffusion layer formed in the sample of Example 2 and the temperature of diffusion heat treatment. Curve 3 is a curve obtained by adding V 2 O 5 to the first element, and curve 4 ( (Broken line) is V 2 O
5 is not added. The diffusion heat treatment time is 2 hours which is constant for each temperature.
曲線１…第１の要素にＴｌＦを用いた試料 曲線２…第１の要素にＴｌＦを用いない試料 曲線３…第１の要素にＶ2 Ｏ5 を添加した試料 曲線４…第１の要素にＶ2 Ｏ5 を添加しない試料Curve 1: Sample using TlF for the first element Curve 2: Sample not using TlF for the first element Curve 3: Sample obtained by adding V 2 O 5 to the first element Curve 4: First element Sample without V 2 O 5
Claims (7)
少なくともＴｌ−Ｏの元素で構成される第１の要素と、
少なくともＢａ−Ｃａ−Ｃｕ−Ｏの元素で構成される第
２の要素との拡散熱処理によってＴｌ基酸化物超電導体
を生成することを特徴とするＴｌ基酸化物超電導体の製
造方法。1. The method according to claim 1, wherein the surface of the Ni or Ni-based alloy substrate is
A first element composed of at least an element of Tl-O;
A method for producing a Tl-based oxide superconductor, which comprises producing a Tl-based oxide superconductor by diffusion heat treatment with at least a second element composed of Ba-Ca-Cu-O.
Ｃｕ−Ｏの元素で構成され、その原子比が、Ｔｌを１と
して、Ｂａ：０〜１．０、Ｃａ：０〜１．０、Ｃｕ：０
〜１．０の範囲にあり、また、第２の要素がＢａ−Ｃａ
−Ｃｕ−Ｏの元素で構成され、その原子比が、Ｂａを１
としてＣａ：０．５〜３．０、Ｃｕ：０．５〜４．０の
範囲にあることを特徴とする請求項１に記載のＴｌ基酸
化物超電導体の製造方法。2. The method according to claim 1, wherein the first element is Tl-Ba-Ca-
It is composed of an element of Cu—O, and its atomic ratio is Ba: 0 to 1.0, Ca: 0 to 1.0, and Cu: 0, where Tl is 1.
~ 1.0, and the second element is Ba-Ca
-Cu-O element, whose atomic ratio is Ba to 1
The manufacturing method of the Tl-based oxide superconductor according to claim 1, wherein Ca: 0.5 to 3.0 and Cu: 0.5 to 4.0.
ｌＦ、ＢａＦ2 、ＣａＦ2 、ＣｕＦ2 から選択された１
種または２種以上フッ化物であることを特徴とする請求
項１または２に記載のＴｌ基酸化物超電導体の製造方
法。3. The first and second elements are characterized in that the raw material is T
1 selected from IF, BaF 2 , CaF 2 and CuF 2
The method for producing a Tl-based oxide superconductor according to claim 1 or 2, wherein the method is a kind or two or more kinds of fluorides.
比でＴｌを１としてＶ：０．２〜４．０となる範囲で添
加することを特徴とする請求項１ないし３のいずれか１
に記載のＴｌ基酸化物超電導体の製造方法。4. A method according to claim 1, wherein the first element further comprises V 2 O 5 added in an atomic ratio of Tl of 1 to V: 0.2 to 4.0. Any one of
3. The method for producing a Tl-based oxide superconductor according to 1.).
２の要素を被覆して予備熱処理し、さらにその上に第１
の要素を被覆し、得られた複合体を拡散熱処理すること
を特徴とする請求項１ないし４のいずれか１に記載する
Ｔｌ基酸化物超電導体の製造方法。5. A second element is coated on the surface of a substrate made of Ni or a Ni-based alloy, preliminarily heat-treated, and further,
The method for producing a Tl-based oxide superconductor according to any one of claims 1 to 4, wherein the element is coated and the obtained composite is subjected to diffusion heat treatment.
混合して得た複合粉末を、ＮｉあるいはＮｉ基合金で作
製されたシース材の内部に充填し、拡散熱処理すること
を特徴とする請求項１ないし４のいずれか１に記載のＴ
ｌ基酸化物超電導体の製造方法。6. A method of filling a composite powder obtained by mixing powders of the first element and the second element into a sheath material made of Ni or a Ni-based alloy and performing a diffusion heat treatment. The T according to any one of claims 1 to 4, characterized in that:
A method for producing an l-based oxide superconductor.
以上の酸素を含む雰囲気中で、３００℃ないし６５０℃
の範囲で焼鈍を行うことを特徴とする請求項１ないし６
のいずれか１に記載のＴｌ基酸化物超電導体の製造方
法。7. Oxygen or 50 mol% after the diffusion heat treatment.
300 ° C to 650 ° C in the above atmosphere containing oxygen
The annealing is performed in the range of (1) to (6).
The method for producing a Tl-based oxide superconductor according to any one of the above.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21244496A JP3979609B2 (en) | 1996-08-12 | 1996-08-12 | Method for producing Tl-based oxide superconductor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21244496A JP3979609B2 (en) | 1996-08-12 | 1996-08-12 | Method for producing Tl-based oxide superconductor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1059718A true JPH1059718A (en) | 1998-03-03 |
| JP3979609B2 JP3979609B2 (en) | 2007-09-19 |
Family
ID=16622721
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21244496A Expired - Lifetime JP3979609B2 (en) | 1996-08-12 | 1996-08-12 | Method for producing Tl-based oxide superconductor |
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| Country | Link |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1089068C (en) * | 1995-12-22 | 2002-08-14 | 电装株式会社 | Rotary-type door apparatus having two engagement portions for manual or automatic driving |
-
1996
- 1996-08-12 JP JP21244496A patent/JP3979609B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1089068C (en) * | 1995-12-22 | 2002-08-14 | 电装株式会社 | Rotary-type door apparatus having two engagement portions for manual or automatic driving |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3979609B2 (en) | 2007-09-19 |
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