JPH05208817A - Production of oxide-based superconducting material - Google Patents

Abstract

PURPOSE:To enable production of a uniform and dense superconductor consecutive in a layer state, control of thickness of superconductive layer and formation of composition having uniform direction of crystal in production of superconducting material by diffusion reaction, by heat-treating a composite material consisting of a first element containing Ag and a second element. CONSTITUTION:A composite material of a first element comprising the whole or part of components constituting a superconductor and Ag and a second element comprising the whole or part of the components constituting the superconductor is prepared. The composite material is heat-treated to form a superconductor at the interface between both the elements by diffusion reaction. For example, powdery Y2O3, BaCO3 and CuO are blended in a composition of 2:1:1 calcined, molded and burnt to form a second element. Separately, powdery BaCO3 and CuO are blended so as to form a ratio of 0.3:5, calcined, burnt, ground, mixed with a given amount of Ag powder and mixed to give a first element. The first element is suspended in PVA to give a slurry, which is applied to the second element to give a composite material. The composite material is heat-treated to give a Y-Ba-Cu-O-based oxide superconductor.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、医療診断用磁気共鳴映
像装置（ＭＲＩ−ＣＴ）等の超電導マグネット線材や、
超電導送電等の導電材として有望視され、開発が進めら
れている高臨界温度酸化物系超電導材料の製造方法に関
する。BACKGROUND OF THE INVENTION The present invention relates to a superconducting magnet wire rod such as a magnetic resonance imaging apparatus for medical diagnosis (MRI-CT),
The present invention relates to a method for producing a high critical temperature oxide-based superconducting material, which is promising as a conductive material for superconducting power transmission and is under development.

【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が液体窒素温度を超える値をもつＹ（イット
リウム）基（ＹＢａ₂ Ｃｕ₃ Ｏ_7-x ）、Ｂｉ（ビスマ
ス）基（Ｂｉ₂ Ｓｒ₂ ＣａＣｕ₂ Ｏ_8+x 他）、Ｔｌ（タ
リウム）基（Ｔｌ₂ Ｂａ₂ ＣａＣｕ₂ Ｏ_8+x 他）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
体は高Ｔｃ酸化物と称され、Ｃｕを含んでいることが共
通している。従来のＮｂ−ＴｉやＮｂ₃ Ｓｎ等の金属系
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
が、高Ｔｃ酸化物はこれら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、このことから実用的
にも極めて重要な超電導材料として研究開発が進められ
ている。2. Description of the Related Art Y (yttrium) group (YBa ₂ Cu ₃ O _7-x ), Bi (bismuth) group (Bi ₂ ) having a critical temperature Tc at which a normal-conducting state transitions to a superconducting state exceeds a liquid nitrogen temperature. Oxide superconductors such as Sr ₂ CaCu ₂ O _{8 + x} ) and Tl (thallium) group (Tl ₂ Ba ₂ CaCu ₂ O _{8 + x} ) have been discovered. These oxide superconductors are called high Tc oxides, and it is common that they contain Cu. Although metal-based superconductor, such as a conventional Nb-Ti and Nb ₃ Sn was necessary to cool with a liquid helium, remarkably favorable cooling conditions high Tc oxide compared to those metallic superconductors Therefore, research and development is being conducted as a superconducting material that is extremely important for practical use.

【０００３】酸化物超電導体は、機械的性質が極めて脆
いため、線材の形に加工する手法の一例として次の様な
粉末法が行われている。この粉末法は、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等の金属管に充
填し、これをスエージング、線引き、圧延等の方法によ
り所望の径の線あるいは所望の厚さのテープに加工す
る。これに熱処理を施して金属管内部の圧縮混合粉末に
固相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、超電導線材を製造する、いわゆる粉末法と
よばれる方法である。Since the oxide superconductor has extremely brittle mechanical properties, the following powder method is used as an example of a method of processing into a wire shape. According to this powder method, a plurality of raw material powders containing elements forming an oxide superconductor are calcined to remove unnecessary components, and then the calcined powders are filled in a metal tube such as Ag and swaged. A wire having a desired diameter or a tape having a desired thickness is processed by a method such as drawing, drawing, or rolling. This is a so-called powder method, in which a superconducting wire is manufactured by subjecting this to heat treatment to cause a solid-phase reaction in the compressed mixed powder inside the metal tube to generate an oxide superconductor having a desired composition.

【０００４】[0004]

【発明が解決しようとする課題】従来の粉末法による製
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完全に
均一な組成とならない問題があった。とくに長尺線材で
は線材全長にわたり均一な組成の超電導体を生成できな
い。このため不適当な組成で不充分な超電導特性をもつ
局部を形成することとなり、この結果、線材全体の特性
が制限されてしまう問題点があった。In the conventional manufacturing method by the powder method, it is difficult to mix the raw material powders completely and uniformly. Therefore, even if heat treatment is applied, the entire superconductor does not have a completely uniform composition. There was a problem. In particular, a long wire cannot produce a superconductor having a uniform composition over the entire length of the wire. Therefore, a local portion having an unsuitable composition and insufficient superconducting properties is formed, resulting in a problem that the properties of the entire wire are limited.

【０００５】また、上記の線材内部に形成されている酸
化物超電導体は粉末を圧縮した成形体を固相反応により
焼結したもので、その内部に微細な空孔が多数存在す
る。このことから、従来の金属系超電導体に比較して緻
密性に欠け、実用上重要な臨界電流密度Ｊｃを高めるの
が困難な問題点があった。Further, the oxide superconductor formed inside the above wire is a compacted powder compact that is sintered by a solid phase reaction, and has a large number of fine pores inside. For this reason, there is a problem that it is difficult to increase the critical current density Jc, which is lacking in denseness and is practically important as compared with the conventional metal-based superconductor.

【０００６】さらに、酸化物超電導体では、その結晶の
ｃ軸方向とａｂ軸方向とで著しく超電導特性が異なるた
め、各結晶の方位を揃え、特性のすぐれた方向で使用す
る必要がある。従来の粉末法では、結晶方位を揃えるた
めには、極めて強度の加工を加えるなどの複雑な作業が
必要であった。そのようなことから、従来の粉末法より
も一歩進んだ酸化物系超電導材料の線材化法の開発が待
望されていた。Further, in an oxide superconductor, since the superconducting properties of the crystals are significantly different in the c-axis direction and the ab-axis direction, it is necessary to align the orientations of the crystals and to use them in the directions with excellent properties. In the conventional powder method, in order to align the crystal orientation, complicated work such as extremely strong working is required. Under such circumstances, there has been a long-awaited demand for development of a method for converting an oxide-based superconducting material into a wire, which is a step further than the conventional powder method.

【０００７】本発明の目的とするところは、均一な組成
をもつ緻密な酸化物超電導体を層状に連続して生成させ
ることが出来、しかも超電導層の厚さを所望の大きさに
制御し、さらに、結晶方位の揃った組織を短時間で得る
ことが出来る酸化物系超電導材料の製造方法を提供する
ものである。The object of the present invention is to form a dense oxide superconductor having a uniform composition continuously in a layered manner and to control the thickness of the superconducting layer to a desired size. Further, the present invention provides a method for producing an oxide-based superconducting material, which can obtain a structure with uniform crystal orientation in a short time.

【０００８】[0008]

【課題を解決するための手段】本発明者は、上記目的を
達成する方法として、２つの要素の間の拡散反応による
超電導体の製造方法（複合加工法とも呼ばれる）に着目
した。このような拡散反応による超電導体の製造は、酸
化物超電導体同様に機械的性質が硬く脆くて直接的加工
が困難なＮｂ₃ Ｓｎ，Ｖ₃ Ｇａ等の金属間化合物超電導
体の線材化に適用され、これらの工業化に大きい成功を
収めた（例えばＫ．Ｔａｃｈｉｋａｗａ．Ｆｉｌａｍｅ
ｎｌａｖｙ Ａ１５ Ｓｕｐｅｒｃｏｎｄｕｃｔｏｒ
ｓ．Ｐｌｅｎｕｍ Ｐｒｅｓｓ，（１９８０），１頁参
照）。この方法では、ＣｕにＳｎまたはＧａを含ませた
合金（第一の要素）とＮｂまたはＶ（第二の要素）との
２つの要素からなる複合体を加工後、熱処理して両者の
界面に超電導体を生成させる。この際、Ｃｕは超電導体
に含まれることがなく、拡散反応を促進する効果があ
る。この方法によると、均一な組成をもった緻密な超電
導体を連続して生成し、優れた超電導特性をうることが
できるし、さらに速い磁界変化に対して超電導性が安定
に保たれる極細多芯形式の線材を容易に作製できるの
で、実用上とくに有意義である。As a method for achieving the above object, the present inventor has focused on a method for producing a superconductor (also called a composite processing method) by a diffusion reaction between two elements. The production of superconductors by such a diffusion reaction is applied to wire formation of intermetallic compound superconductors such as Nb ₃ Sn and V ₃ Ga, which are hard and brittle in mechanical properties and are difficult to be directly processed, like oxide superconductors. Have been highly successful in their industrialization (eg K. Tachikawa. Filme.
nlavy A15 Superconductor
s. Plenum Press, (1980), p. 1). In this method, a composite consisting of two elements of an alloy (first element) containing Sn or Ga in Cu and Nb or V (second element) is processed and then heat treated to form an interface between the two. Generate a superconductor. At this time, Cu is not contained in the superconductor and has an effect of promoting the diffusion reaction. According to this method, a dense superconductor having a uniform composition can be continuously produced, excellent superconducting properties can be obtained, and the superconductivity can be stably maintained even when the magnetic field changes rapidly. Since a core-type wire can be easily produced, it is particularly useful in practice.

【０００９】本発明者らは、さきに拡散法をＹ系酸化物
超電導体の合成に適用し、２１１（Ｙ系では、各数値は
順にＹ，Ｂａ，Ｃｕの原子組成比を示す）酸化物と０３
５酸化物を２つの要素として拡散を行い、１２３超電導
相をえたが、結晶配向性はえられなかった（Ｋ．Ｔａｃ
ｈｉｋａｗａ他、Ｊａｐ．Ｊ．Ａｐｐｌ．Ｐｈｙ．，Ｖ
ｏｌ２７（１９８８）ＰＬ１５０１参照）。また、Ｂｉ
系酸化物については、０２１２（Ｂｉ系では、各数値は
順にＢｉ，Ｓｒ，Ｃａ，Ｃｕの原子組成比を示す）酸化
物と２００１酸化物を２つの要素として拡散を行い、２
２１２超電導相をえた（Ｋ．Ｔａｃｈｉｋａｗａ他、Ｊ
ａｐ．Ｊ．Ａｐｐｌ．Ｐｈｙｓ．，Vol３０（１９９
１）Ｐ６３９参照）。本発明はこれらの拡散法を改良
し、さらに、酸化物超電導材料の新しい線材化法の道を
拓いたものである。The present inventors previously applied the diffusion method to the synthesis of a Y-based oxide superconductor, and made 211 (in the Y-based, each numerical value represents the atomic composition ratio of Y, Ba, and Cu) oxide. And 03
Diffusion was performed by using 5 oxide as two elements, and 123 superconducting phase was obtained, but crystal orientation was not obtained (K. Tac
hikawa et al., Jap. J. Appl. Phy. , V
ol27 (1988) PL1501). Also, Bi
Regarding the system oxides, 0212 (in the case of the Bi system, each numerical value indicates the atomic composition ratio of Bi, Sr, Ca, Cu in order) and the oxide 2001 are used as two elements to diffuse, and
212 Superconducting phase was obtained (K. Tachikawa et al., J.
ap. J. Appl. Phys. , Vol30 (199
1) See P639). The present invention improves these diffusion methods and further opens the way to a new wire forming method for oxide superconducting materials.

【００１０】すなわち本発明は、酸化物超電導体を構成
する成分の全部又は一部とＡｇとからなる第一の要素
と、酸化物超電導体を構成する成分の全部又は一部から
なる第二の要素との複合体を作る工程と、この複合体を
熱処理して、第一の要素と第二の要素との界面に、拡散
反応により酸化物超電導体を生成せしめる工程とを具備
したことを特徴とする酸化物超電導体の製造方法であ
る。That is, according to the present invention, the first element consisting of all or part of the constituents of the oxide superconductor and Ag and the second element consisting of all or part of the constituents of the oxide superconductor. And a step of forming a composite with the element and a step of heat-treating the composite to generate an oxide superconductor at the interface between the first element and the second element by a diffusion reaction. And a method for producing an oxide superconductor.

【００１１】本発明では、Ａｇを含む第一の要素と他の
第二の要素とを拡散反応させると、反応が著しく促進さ
れて従来より低い温度で短時間の反応で超電導相が生成
される。Ａｇは超電導相には含まれず、重力に抗して試
料表面に押出される。その機構は、まず第一の要素と第
二の要素との境界に超電導相が生成されると、その外側
に超電導相から押出されたＡｇが集積して、さらに拡散
が促進され、遂にＡｇが表面に集積するものと考えられ
る。本発明で見出されたこの現象は、さきにのべた拡散
法によるＮｂ₃ ＳｎやＶ₃ Ｇａの生成におけるＣｕの効
果と類似している。このＡｇの移動に伴ない、酸化物超
電導相の結晶配向性が改善され、超電導線材の実用上に
最も重要な特性である臨界電流密度Ｊｃが高められる。
また、コンピューター等に有用な超電導素子は、超電導
体と常電導体の積層体からなるので、超電導体とＡｇ
（常電導体）との積層体が容易に作製出来る本製造法
は、超電導素子応用の面からも重要である。さらに、酸
化物系超電導体は、金属系超電導体と異なり、リード線
の接続が困難であるが、本製造法により、超電導体とよ
く密着したＡｇとの積層体が作製出来るので電気的な接
続上も極めて有利である。In the present invention, when the first element containing Ag and the other second element are diffusion-reacted, the reaction is remarkably promoted, and a superconducting phase is produced in a reaction at a lower temperature and a shorter time than in the prior art. .. Ag is not contained in the superconducting phase and is extruded onto the sample surface against gravity. The mechanism is that when a superconducting phase is first generated at the boundary between the first element and the second element, Ag extruded from the superconducting phase accumulates on the outside of the superconducting phase, further promoting diffusion, and finally Ag. It is considered to accumulate on the surface. This phenomenon found in the present invention is similar to the effect of Cu on the formation of Nb ₃ Sn and V ₃ Ga by the above-mentioned diffusion method. With the migration of Ag, the crystal orientation of the oxide superconducting phase is improved, and the critical current density Jc, which is the most important characteristic for practical use of the superconducting wire, is increased.
In addition, since a superconducting element useful for a computer or the like is composed of a laminated body of a superconductor and a normal conductor,
This manufacturing method, which can easily produce a laminated body with (normal conductor), is important from the viewpoint of application of superconducting elements. Furthermore, unlike metal-based superconductors, it is difficult to connect lead wires to oxide-based superconductors, but this manufacturing method makes it possible to produce a laminate with Ag that is in close contact with the superconductor, so that electrical connection is possible. The above is also extremely advantageous.

【００１２】次に、本発明の具体的な態様についてのべ
る。Next, specific embodiments of the present invention will be described.

【００１３】まず、酸化物超電導体の構成元素からなる
第二の要素（例えば、前述のＹ系における２１１酸化物
あるいはＢｉ系における０２１２酸化物）を混合、成
型、焼成する。その上にＡｇを含む第一の要素（Ａｇを
除く組成は、例えば前述のＹ系における０３５酸化物あ
るいはＢｉ系における２００１酸化物）を被覆して複合
体を作製する。第一の要素の被覆法は、第一の要素の粉
末を溶剤に懸濁してスプレーまたは塗布してもよい。つ
いでこの複合体を大気中または酸素雰囲気中で熱処理を
行い、第一の要素と第二の要素との界面に超電導相を生
成させる。First, a second element consisting of the constituent elements of the oxide superconductor (for example, the above-mentioned 211 oxide in Y system or 0212 oxide in Bi system) is mixed, molded and fired. A first element containing Ag (the composition excluding Ag is, for example, the above-mentioned 035 oxide in Y system or 2001 oxide in Bi system) is coated thereon to prepare a composite. The method of coating the first element may involve spraying or applying the powder of the first element in a solvent. Then, this composite is heat-treated in the air or an oxygen atmosphere to generate a superconducting phase at the interface between the first element and the second element.

【００１４】さらに、本発明では、第一の要素をＡｇを
主体とし、一方、第二の要素をＹ系，Ｂｉ系，Ｔｌ系酸
化物の共通的な構成元素であるＣｕを主体とすると、加
工性のよい要素を組合わせることが可能となり、両者の
複合体を線状、テープ状あるいは管状に成型、加工後熱
処理を行い、両者の界面に拡散反応により超電導相を生
成させることが出来る。その結果、さきにＮｂ₃ Ｓｎや
Ｖ₃ Ｇａの線材化に用いられた複合加工法のように実用
的価値の高い極細多芯形式の線材を作製しうるようにな
る。加工性を有するＡｇと酸化物超電導体構成元素から
なる第一の要素を作製するには、Ａｇ金属を溶融し、こ
れにＹ，Ｂｉ，Ｔｌその他の構成元素を溶解せしめて、
Ａｇ合金を作製してもよいし、Ａｇ金属粉またはＡｇ₂
Ｏ（酸化銀）粉末とＹ₂ Ｏ₃ （酸化イットリウム）、Ｂ
ｉ₂ Ｏ₃ （酸化ビスマス）、Ｔｌ₂ Ｏ₃ （酸化タリウ
ム）その他の構成元素の酸化物粉末を混合し、成型、焼
結してもよい。同様にして、ＣｕまたはＣｕＯ（酸化
銅）と酸化物超電導体構成元素からなる、加工の可能な
第二の要素を作製することが出来る。Further, in the present invention, when the first element is mainly composed of Ag, while the second element is mainly composed of Cu which is a common constituent element of Y-based, Bi-based and Tl-based oxides, It becomes possible to combine elements having good workability, and it is possible to form a composite of the both into a linear shape, a tape shape, or a tubular shape, perform heat treatment after processing, and generate a superconducting phase at the interface between the two by a diffusion reaction. As a result, it becomes possible to manufacture an ultrafine multicore type wire rod having a high practical value, such as the composite processing method used for forming Nb ₃ Sn or V ₃ Ga wire rods. In order to produce the first element composed of Ag and the oxide superconductor constituent element having workability, Ag metal is melted and Y, Bi, Tl and other constituent elements are melted,
Ag alloy may be prepared, or Ag metal powder or Ag ₂
O (silver oxide) powder and Y ₂ O ₃ (yttrium oxide), B
It is also possible to mix oxide powders of i ₂ O ₃ (bismuth oxide), Tl ₂ O ₃ (thallium oxide) and other constituent elements, and then mold and sinter. Similarly, a processable second element composed of Cu or CuO (copper oxide) and an oxide superconductor constituent element can be produced.

【００１５】ここで、第一の要素中のＡｇの含有量は、
５〜９０モル％の範囲が好適であり、５％以下では前述
した拡散促進の効果が少なく、また、９０％以上である
と酸化物超電導体の構成元素が不足して、拡散後優れた
超電導特性がえられ難い。なお、より好ましくは１０〜
７０モル％の範囲が適当であり、また、第一の要素に加
工性を付与するにはＡｇのモル％が４０％以上であるこ
とが好ましい。第二の要素の組成は、第一の要素の組成
に対応して、種々の組成が可能である。第二の要素に加
工性を付与し、しかも優れた超電導特性をうるには、Ｃ
ｕのモル％が４０〜９０％の範囲であることが好まし
い。Here, the content of Ag in the first element is
The range of 5 to 90 mol% is preferable, and if it is 5% or less, the above-mentioned effect of promoting diffusion is small, and if it is 90% or more, the constituent elements of the oxide superconductor are insufficient, resulting in excellent superconductivity after diffusion. It is difficult to obtain the characteristics. In addition, more preferably 10 to
The range of 70 mol% is suitable, and the mol% of Ag is preferably 40% or more in order to impart processability to the first element. The composition of the second element can be of various compositions, corresponding to the composition of the first element. To impart workability to the second element and to obtain excellent superconducting properties, C
It is preferable that the mol% of u is in the range of 40 to 90%.

【００１６】[0016]

【発明の効果】本発明に基づく２つの要素間の改良され
た拡散法によると、緻密で空孔がなく、組成が均一な高
Ｔｃ酸化物を従来より容易に作製しうる効果がある。ま
た、通常の粉末焼結法と異なり、一方向から構成元素と
Ａｇが移動して超電導相が生成するため、一方向に結晶
粒が生長し、結晶配向性の改善された高Ｔｃ酸化物超電
導材料を得ることができる。さらに、２つの拡散要素に
加工性を付与することが出来るので、両者を複合して加
工すると極細多芯形式の線材を作製することを可能にす
る。一方、本発明によると、高Ｔｃ超電導体とＡｇとの
積層体を作製出来るので、超電導素子に対する応用上や
電気的接続上に有効である。According to the improved diffusion method between two elements based on the present invention, there is an effect that a dense and void-free high Tc oxide having a uniform composition can be produced more easily than before. Further, unlike the normal powder sintering method, the constituent elements and Ag move from one direction to generate a superconducting phase, so that the crystal grains grow in one direction and the high Tc oxide superconducting material with improved crystal orientation. The material can be obtained. Further, since it is possible to impart workability to the two diffusing elements, it is possible to fabricate an ultrafine multicore type wire rod by processing the two diffusing elements in combination. On the other hand, according to the present invention, a laminate of a high Tc superconductor and Ag can be produced, which is effective for application to a superconducting element and electrical connection.

【００１７】[0017]

【実施例】【Example】

実施例１（Ｙ−Ｂａ−Ｃｕ−Ｏ系酸化物超電導体の製造
方法） Ｙ₂ Ｏ₃ ，ＢａＣＯ₃ ，ＣｕＯの原料粉末を２１１組成
になるように配合し、９００℃で２０時間仮焼後、幅４
mm、長さ３０mm、厚さ１mmの短冊状に成型し、９５０℃
で２０時間焼成してＹ系第二の要素を作製した。別に、
ＢａＣＯ₃ とＣｕＯの原料粉末を０３５組成になるよう
に配合し、８００℃で２０時間仮焼後、９００℃で２０
時間焼成した。これを粉砕し、２０モル％のＡｇ粉末を
加えて混合して第一の要素を作製し、これをポリビニー
ルアルコールに懸濁させたスラリーを第二の要素の上に
厚さ１００μｍ塗布して複合体を作製した。Example 1 (Y-Ba-CuO-based method for preparing an oxide _{superconductor) Y 2 O 3, BaCO 3} , CuO raw material powder was blended so that the 211 composition, after 20 hours calcining at 900 ° C. , Width 4
mm, length 30 mm, thickness 1 mm, shaped into a strip at 950 ° C
And baked for 20 hours to prepare a Y-type second element. Apart from
Raw material powders of BaCO ₃ and CuO were blended so as to have a composition of 035, calcined at 800 ° C. for 20 hours, and then at 20 ° C. at 20 ° C.
Burned for hours. This was crushed, 20 mol% Ag powder was added and mixed to prepare a first element, and a slurry prepared by suspending this in polyvinyl alcohol was applied on the second element to a thickness of 100 μm. A composite was made.

【００１８】この複合体を種々の温度で３時間熱処理し
てＴｃを測定したところ、８８０℃で最も高い９２Ｋの
Ｔｃが得られた。Ａｇを含まない０３５酸化物を塗布す
ると９４０℃で最も高い９２ＫのＴｃが得られたので、
Ａｇの添加により最適熱処理温度が６０℃低下した。つ
いで７７ＫにおけるＪｃを測定したところ、本実施例に
より温度８８０℃で３時間大気中で拡散処理した試料は
３０００Ａ／cm² となり、比較例のＡｇを含まない０３
５酸化物を用いて９４０℃で３時間拡散熱処理した試料
で得られた１１００Ａ／cm² の約３倍の大きい値となっ
た。When this composite was heat-treated at various temperatures for 3 hours and Tc was measured, the highest Tc of 92K was obtained at 880 ° C. Applying 035 oxide containing no Ag gave the highest Tc of 92K at 940 ° C.
The optimum heat treatment temperature was lowered by 60 ° C. by adding Ag. Then, Jc at 77K was measured, and the sample subjected to diffusion treatment in the atmosphere at a temperature of 880 ° C. for 3 hours according to the present example was 3000 A / cm ² , and the sample containing no Ag of Comparative Example 03
The value was about 3 times as large as 1100 A / cm ² obtained in the sample which was subjected to diffusion heat treatment at 940 ° C. for 3 hours using 5 oxide.

【００１９】本実施例の８８０℃で３時間熱処理した試
料の断面組織を観察すると、拡散生成した１２３超電導
相の内にはＡｇは殆んど存在せず、試料表面全体にわた
って厚さ約２０μｍのＡｇ層が形成されていた。また超
電導相の結晶粒は、比較例のＡｇを含まない試料に比べ
て拡散方向によく配列しており、これが前述のＪｃの増
加をもたらしたものと考えられる。Observation of the cross-sectional structure of the sample heat-treated at 880 ° C. for 3 hours in this Example revealed that almost no Ag was present in the 123 superconducting phases produced by diffusion, and the thickness was about 20 μm over the entire sample surface. An Ag layer was formed. Further, the crystal grains of the superconducting phase are better aligned in the diffusion direction than the sample containing no Ag of the comparative example, which is considered to have caused the increase of Jc.

【００２０】実施例２（Ｂｉ−Ｓｒ−Ｃａ−Ｃｕ−Ｏ系
酸化物超電導体の製造方法） ＳｒＣＯ₃ ，ＣａＣＯ₃ ，ＣｕＯの原料粉を用いて、実
施例１と同様な方法で、０２１２組成をもつＢｉ系酸化
物の第二の要素を作製した。また、３０モル％のＡｇを
含む２００１組成の第一の要素をＢｉ₂ Ｏ₃ ，ＣｕＯの
原料粉を用いて実施例１と同様な方法で作製し、上記第
二の要素の上に塗布した。この複合体を大気中で８３０
℃で２時間熱処理した試料断面の元素分布を電子線ブロ
ーブマイクロアナライザーにより調べた結果を図１に示
す。第二の要素の上に約１５０μｍの拡散層が生成さ
れ、その組成を電子銃プローブマイクロアナライザーで
分析したところ、２２１２相に相当していた。なお、別
に第二の要素と２２１２超電導相の間にＢｉの少ない非
超電導相が薄く生成されている。Ａｇは超電導相から押
出されて、表面に厚さ約３０μｍ集積しており、超電導
体とＡｇとの積層体が形成された。実施例２による試料
は８１ＫのＴｃを示した。また、図２には、拡散方向に
垂直に磁界を加えた場合の超電導相の４．２Ｋにおける
磁化履歴曲線を示した。この曲線から見積られたＪｃは
７７０００Ａ／cm² の大きい値となり、緻密で良質な超
電導相が生成されたことを示した。Example 2 (Method for producing Bi-Sr-Ca-Cu-O-based oxide superconductor) A 0212 composition was prepared in the same manner as in Example 1, using raw material powders of SrCO ₃ , CaCO ₃ , and CuO. A second element of a Bi-based oxide having was prepared. A first element of 2001 composition containing 30 mol% of Ag was prepared in the same manner as in Example 1 using raw material powders of Bi ₂ O ₃ and CuO, and applied on the second element. .. 830 this complex in the atmosphere
FIG. 1 shows the result of examining the element distribution in the cross section of the sample heat-treated at 2 ° C. for 2 hours with an electron probe microanalyzer. A diffusion layer of about 150 μm was formed on the second element, and its composition was analyzed by an electron gun probe microanalyzer, and it corresponded to 2212 phase. In addition, a non-superconducting phase having a small amount of Bi is thinly formed between the second element and the 2212 superconducting phase. Ag was extruded from the superconducting phase and accumulated on the surface to a thickness of about 30 μm to form a laminate of the superconductor and Ag. The sample according to Example 2 showed a Tc of 81K. Further, FIG. 2 shows a magnetization history curve at 4.2 K of the superconducting phase when a magnetic field is applied perpendicularly to the diffusion direction. The Jc estimated from this curve was a large value of 77,000 A / cm ² , indicating that a dense and high-quality superconducting phase was produced.

【００２１】実施例３（Ｔｌ−Ｂａ−Ｃａ−Ｃｕ−Ｏ系
酸化物超電導体の製造方法） ＢａＣＯ₃ ，ＣａＣＯ₃ ，ＣｕＯの原料粉を用いて、実
施例１と同様な方法で、０１１２組成をもつＴｌ系酸化
物の第二の要素を作製した。また、４０モル％のＡｇを
含む２００１組成の第一の要素を、Ｔｌ₂ Ｏ₃ とＣｕＯ
の原料粉を用いて実施例１と同様な方法で作製し、上記
第二の要素の上に塗布して複合体を作製した。この複合
体を大気中で８５０℃で２時間熱処理すると、１０５Ｋ
のＴｃが得られた。その断面組織は実施例２の図１に類
似しており、超電導体とＡｇとの積層体を作製すること
ができた。[0021] with (production method of Tl-Ba-Ca-CuO-based oxide superconductor) BaCO _3, CaCO _3, CuO raw material powder of Example 3, in the same manner as in Example 1., 0112 composition A second element of the Tl-based oxide with was prepared. In addition, the first element of the 2001 composition containing 40 mol% Ag is Tl ₂ O ₃ and CuO.
A raw material powder of No. 1 was used to prepare a composite material in the same manner as in Example 1, and the above second element was applied to prepare a composite. When this composite is heat-treated at 850 ° C. for 2 hours in the atmosphere, it is 105K
Was obtained. The cross-sectional structure was similar to that of FIG. 1 of Example 2, and a laminate of a superconductor and Ag could be manufactured.

【００２２】実施例４（Ｙ−Ｂａ−Ｃｕ−Ｏ系酸化物超
電導体の製造方法） Ａｇ粉とＹ₂ Ｏ₃ 粉末を混合し、直径１０mm、長さ５０
mmに成型し、７５０℃で３時間予備焼成した後、８５０
℃で３時間焼成し、Ａｇを６０モル％含むＹ系酸化物の
第一の要素を作製した。また、Ｃｕ粉とＢａＯ粉末を混
合し、直径５mm、長さ５０mmに成型し、真空中で８００
℃で３時間焼成し、Ｃｕを７０モル％含む第二の要素を
作製した。第一の要素の中心に直径５．１mmの孔を貫通
して、その中に第二の要素を挿入して複合体を作製し
た。この複合体を溝ロールとスエージングにより直径２
mmの線状に加工し、８８０℃で８時間大気中で熱処理す
ると、第一の要素と第二の要素の界面に８７ＫのＴｃを
もつ１２３超電導体を生成することが出来た。Example 4 (Manufacturing Method of Y-Ba-Cu-O Oxide Superconductor) Ag powder and Y ₂ O ₃ powder were mixed and the diameter was 10 mm and the length was 50.
850 mm after molding into mm and pre-baking at 750 ° C for 3 hours
The first element of Y-based oxide containing 60 mol% of Ag was prepared by firing at 3 ° C. for 3 hours. Also, Cu powder and BaO powder are mixed and molded into a diameter of 5 mm and a length of 50 mm, and the temperature is 800 in vacuum.
A second element containing 70 mol% of Cu was prepared by firing at 3 ° C. for 3 hours. A composite was prepared by penetrating a hole having a diameter of 5.1 mm in the center of the first element and inserting the second element therein. This composite was made to have a diameter of 2 by groove roll and swaging.
It was possible to produce 123 superconductors having a Tc of 87K at the interface between the first element and the second element when processed into a linear shape of mm and heat-treated at 880 ° C. for 8 hours in the atmosphere.

【図面の簡単な説明】[Brief description of drawings]

【図１】実施例２の試料断面におけるＢｉ，Ｓｒ，Ｃ
ａ，Ｃｕ及びＡｇの元素の分布をを示す金属組織の写
真。FIG. 1 shows Bi, Sr, and C in a sample cross section of Example 2.
The photograph of the metal structure which shows distribution of the element of a, Cu, and Ag.

【図２】実施例２の試料の４．２Ｋにおける磁化履歴曲
線を示す図。FIG. 2 is a diagram showing a magnetization history curve of a sample of Example 2 at 4.2K.

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Claims (7)

【特許請求の範囲】[Claims] 【請求項１】 酸化物超電導体を構成する成分の全部又
は一部とＡｇとからなる第一の要素と、酸化物超電導体
を構成する成分の全部又は一部からなる第二の要素との
複合体を作る工程と、 この複合体を熱処理して、第一の要素と第二の要素との
界面に、拡散反応により酸化物超電導体を生成せしめる
工程とを具備したことを特徴とする酸化物系超電導体の
製造方法。1. A first element comprising all or a part of components constituting an oxide superconductor and Ag, and a second element comprising all or a part of components constituting an oxide superconductor. An oxidation characterized by comprising a step of forming a composite and a step of heat-treating the composite to produce an oxide superconductor at an interface between the first element and the second element by a diffusion reaction. Method for manufacturing physical superconductor. 【請求項２】 前記酸化物超電導体が、Ｙ−Ｂａ−Ｃｕ
−Ｏ系であることを特徴とする、請求項１に記載の酸化
物系超電導体の製造方法。2. The oxide superconductor is Y-Ba-Cu.
The oxide superconductor manufacturing method according to claim 1, wherein the oxide superconductor is -O based. 【請求項３】 前記酸化物超電導体が、Ｂｉ−Ｓｒ−Ｃ
ａ−Ｃｕ−Ｏ系であることを特徴とする、請求項１に記
載の酸化物系超電導体の製造方法。3. The oxide superconductor is Bi—Sr—C.
It is a-Cu-O system, The manufacturing method of the oxide superconductor of Claim 1 characterized by the above-mentioned. 【請求項４】 前記酸化物超電導体が、Ｔｌ−Ｂａ−Ｃ
ａ−Ｃｕ−Ｏ系であることを特徴とする、請求項１に記
載の酸化物系超導電体の製造方法。4. The oxide superconductor is Tl-Ba-C.
It is a-Cu-O system, The manufacturing method of the oxide superconductor of Claim 1 characterized by the above-mentioned. 【請求項５】 前記第一の要素と第二の要素からなる複
合体を、線状、テープ状あるいは管状に加工した後熱処
理することを特徴とする、請求項１ないし請求項４のい
ずれかに記載の酸化物系超電導体の製造方法。5. The composite of the first element and the second element is heat-treated after being processed into a linear shape, a tape shape, or a tubular shape. The method for producing an oxide-based superconductor according to [4]. 【請求項６】 前記第一の要素の中のＡｇの組成が、５
〜９０モル％であることを特徴とする請求項１ないし請
求項５のいずれかに記載の酸化物系超電導体の製造方
法。6. The composition of Ag in the first element is 5
The method for producing an oxide-based superconductor according to any one of claims 1 to 5, wherein the content is about 90 mol%. 【請求項７】 前記第一の要素はＡｇを４０〜９０モル
％含み、前記第二の要素はＣｕを４０〜９０モル％含む
ことを特徴とする請求項１ないし請求項６のいずれかに
記載の酸化物系超電導体の製造方法。7. The method according to claim 1, wherein the first element contains Ag in an amount of 40 to 90 mol%, and the second element contains Cu in an amount of 40 to 90 mol%. A method for producing the oxide-based superconductor described.