JP4464625B2

JP4464625B2 - Tape-like oxide superconducting wire manufacturing method and manufacturing apparatus thereof

Info

Publication number: JP4464625B2
Application number: JP2003129228A
Authority: JP
Inventors: 裕治青木; 保夫高橋; 隆代長谷川
Original assignee: International Superconductivity Technology Center; SWCC Showa Cable Systems Co Ltd
Current assignee: International Superconductivity Technology Center; SWCC Showa Cable Systems Co Ltd
Priority date: 2003-05-07
Filing date: 2003-05-07
Publication date: 2010-05-19
Anticipated expiration: 2023-05-07
Also published as: JP2004335718A

Description

【０００１】
【発明の属する技術分野】
本発明は、酸化物超電導線の製造方法及びその製造装置に係り、特に揮発性の高い溶媒を用いた原料溶液を基板表面に塗布後、乾燥及び焼成して基板上に超電導膜を形成する有機金属塗布熱分解（MOD）法において、均一な膜厚と特性を有し、超電導マグネット、超電導ケーブル等の機器への使用に適したテープ状酸化物超電導線の製造方法及びその製造装置に関する。
【０００２】
【従来の技術】
希土類123系酸化物超電導体は液体窒素温度における磁場特性が、Bi系超電導体に比べて優れているため、実用的な高い臨界電流密度（Jc）を維持することが可能であり、この線材の実用化に成功すれば、高温領域での優れた特性に加えて、貴金属である銀を使用しない製法が可能であること及び冷媒に液体窒素を使用できることから冷却効率が数十〜数百倍に向上するため、経済的に極めて有利である。この結果、従来経済性の面から適用不可能であった機器に対しても超電導線材を利用することが可能となり、超電導機器の用途及び市場が大幅に拡大することが予測される。
【０００３】
希土類123系超電導体（特にY-123系超電導体、Y：Ba：Cu＝１：２：３のモル比）の結晶系は斜方晶であり、このため、通電特性において材料の特性を発揮させるためには、結晶のCuO面を揃えるだけでなく、面内の結晶方位をも揃えることが要求される。その理由は、僅かな方位のずれが双晶粒界を発生させ、通電特性を低下させることによる。
【０００４】
上記のY-123系超電導体の結晶の面内配向性を高め、かつ面内の方位を揃えながら線材化する製法は、薄膜の作製と規を同一にしている。即ち、テープ状金属基板の上に面内配向度と方位を向上させた中間層を形成し、この中間層の結晶格子をテンプレートとして用いることによって、Y-123系超電導体の結晶の面内配向度と方位を向上させることができる。
【０００５】
さらに、超電導体の臨界電流密度（Jc）は、中間層の結晶性と表面平滑性に依存しており、下地の状態に応じて敏感にその特性が大きく変化することが判明している。
【０００６】
上記のテープ状金属基板の上に面内配向した中間層を形成した2軸配向金属基板の製造技術として、SOE（Surface-Oxidation Epitaxy：表面酸化エピタキシー）法、ISD（Inclined substrate deposition ）法、IBAD（Ion Beam Assisted Deposotion）法とRABiTS（Rolling Assisted Biaxially Textured Substrate）法が知られており、無配向また配向金属テープ上に面内配向度と方位を向上させた中間層を形成することにより、10⁶A／cm²を超えるJcを有するY-123系超電導線材が多く報告されている。
【０００７】
これらの方法の多くは、中間層及び超電導層のいずれについても気相法、例えば、PLD（Pulse Laser Deposition）法を採用している。
【０００８】
近年、気相法を使用しない超電導層の形成方法として、フッ素化合物原料を用いたTFAーMOD法が米国において提案され、この方法による酸化物超電導体は、PLD法やCVD（Chemical Vapor Deposition）法等の化学的蒸着法による気相法によって得られるＹ系酸化物超電薄膜と同程度のJc値を示し、線材のコストダウン化への期待から、再びＹ系酸化物超電体の線材化の研究が盛んに行われている（例えば、非特許文献１参照。）。
【０００９】
上記のＴＦＡーＭＯＤ法は、トリフルオロ酢酸塩を無水メタノール溶媒に溶解した溶液を、酸化物中間層を表面に形成した配向金属基材上に塗布した後、仮焼及び本焼することにより酸化物超電薄膜を形成するもので、通常の有機酸塩熱分解法の熱処理中に生ずる硝酸塩の生成を防ぐために、Ｆを含む有機酸塩（トリフルオロ酢酸塩）を出発原料とするものであり、長尺の金属基材上に連続的に塗膜を形成し焼成することができれば、気相法より簡便な方法によりＹ系酸化物超電テープの製造が可能になる。
【００１０】
しかしながら、上記のTFAーMOD法は、原料溶液の溶媒に無水メタノールを使用しているために溶媒の揮発性が高く、長尺の金属基板上への連続塗布工程中に溶液の著しい濃度変化を生じるため、均一な厚さの塗膜を形成することが非常に困難である上、原料溶液は吸湿性に富み、空気中の水分を溶液中に吸収してゲル化する性質を有するため、長時間空気中に曝すことにより原料溶液の変質を招くという問題がある。
【００１１】
また、スプレードライ法等を採用した場合、長時間の連続運転中に噴出孔の先端で凝固し目詰まり等を生ずるという問題もある。
【００１２】
以上の問題に対して、本発明者等は、密閉系の容器と毛細管現象を利用したビードコーティング法を発明し、これらの問題を解決した。
【００１３】
この方法は、外部に溶液塗布部が形成された密閉容器内に揮発性溶媒を用いた酸化物超電導物質の原料溶液を収容し、溶液塗布部に対して所定の間隔を維持して連続的にテープ状基材を移動せしめるとともに、原料溶液を複数の細管により溶液塗布部へ供給して溶液塗布部とテープ状基材との間に液体メニスカスを形成することにより、テープ状基材表面に連続的に原料溶液を塗布するものである（特願2001−342392号参照）。
【００１４】
さらに、１回で塗布可能な膜厚が薄いという問題もあるが、この塗布厚さは、複数回の塗布〜仮焼工程を繰り返す多層コーティング法の採用により1μmを越える厚膜化が可能となった。
【００１５】
【非特許文献１】
低温工学第35巻第11号、2000年11月25日発行、p.517
【００１６】
【発明が解決しようとする課題】
以上のように、TFAーMOD法における連続塗布工程中の溶液の著しい濃度変化及び原料溶液の変質は、密閉系の容器と毛細管現象を利用したビードコーティング法の採用により解決することができたが、新たな問題として浮上したのが、多層コーティング法における仮焼〜塗布工程のインターバルにおいての仮焼膜表層の変性である。
【００１７】
即ち、一度塗布及び仮焼を行なった膜上に再度TFAーMOD法で塗膜を形成した場合、原料溶液が塗布直後にゲル化して粒状化し、均一な塗膜を形成することが困難となることが生じ易いことが判明した。特に、この現象は、雨の日や梅雨から夏場にかけた湿度の高い時期に多発し、湿度の低い乾燥した時期には発生しない。
【００１８】
この現象は、膜厚及びその特性の均一さが要求される長尺の超電導線材の製造において、今後大きな問題となる。
【００１９】
本発明は、以上の問題を解決するためになされたもので、揮発性の高い溶媒を用いた原料溶液を基材表面に塗布後、焼成してMOD法により均一な膜厚を有する塗膜を安定して形成することのできるテープ状酸化物超電導線の製造方法及びその製造装置を提供することをその目的とする。
【００２０】
【課題を解決するための手段】
以上の目的を達成するために、本発明のテープ状酸化物超電導線の製造方法は、
外部に溶液塗布部が形成された密閉容器内に揮発性溶媒を用いた酸化物超電導物質の原料溶液を収容し、前記溶液塗布部に対して所定の間隔を維持して連続的にテープ状基材を移動せしめるとともに、前記原料溶液を複数の細管により前記溶液塗布部へ供給して前記溶液塗布部と前記テープ状基材との間に液体メニスカスを形成することにより、前記テープ状基材表面に連続的に原料溶液を塗布した後、これを焼成することにより酸化物超電導線を製造する方法において、前記溶液塗布部にテープ状基材を供給するテープ供給装置内のテープ状基材を50℃〜150℃の温度範囲に保持することを特徴とするものである。
【００２１】
また、以上の目的を達成するために、本発明のテープ状酸化物超電導線の製造装置は、内部に揮発性溶媒を用いた酸化物超電導物質の原料溶液を収容するための密閉容器、前記密閉容器の外部に形成された平面状の溶液塗布部及び前記密閉容器を貫通し一端側が前記原料溶液の液面下に開口し他端側が前記平面状の溶液塗布部に開口する複数の細管を備えた原料溶液塗布装置と、前記溶液塗布部に対して所定の間隔を維持して連続的にテープ状基材を移動せしめるテープ移動機構及び前記溶液塗布部にテープ状基材を供給するテープ供給装置とからなる酸化物超電導線の製造装置において、前記テープ供給装置内のテープ状基材を５０℃〜１５０℃の温度範囲に保持する手段を備えるようにしたものである。
【００２２】
【発明の実施の形態】
本発明のテープ状酸化物超電導線の製造方法においては、MOD法により超電導膜が形成されるが、多層コーティングを行う場合、従来、線材サプライから供給される線材は大気暴露した状態にあるため、湿度が高い環境下では仮焼膜表面に大気中の水分子が吸着し易い。線材の長さが長くなるに従い、この大気暴露時間が長くなるために、吸着水分子が増加し、塗布口で塗布された原料溶液と反応してゲル化を生じさせる。
【００２３】
この水分子の仮焼膜表面への吸着の影響を防止するためには、テープ供給装置内のテープ状基材を所定温度に保持する必要がある。このため、線材のサプライ全体を囲い、50℃〜150℃に保温しながら塗布口に線材を供給する。この保温によって表面に吸着した水分子を脱離した後に塗膜されるため、溶液と水分子の反応による影響が防止され、溶液のゲル化を阻止することが可能となる。上記の温度範囲としては、特に100℃±10℃の範囲が好ましい。
【００２４】
この場合の原料溶液は、無水メタノール溶媒中に酸化物超電導物質を構成する元素を所定のモル比で配合したトリフルオロ酢酸塩を溶解した溶液からなるものを用いることが望ましく、ＹＢＣＯの他、ＭＯＤ法、特にＴＦＡ−ＭＯＤ法を適用可能なＮｄ、Ｓｍ、Ｈｏ等の酸化物超電導物質も当然に使用することができる。
【００２５】
本発明のテープ状酸化物超電導線の製造装置においては、溶液塗布部は、密閉容器に着脱可能に取付けられ、溶液塗布部を平面状に形成し、複数の細管がこの溶液塗布部に開口するようにすることが好ましく、また、この複数の細管は、密閉容器中の原料溶液を毛細管現象を利用して溶液塗布部に供給するため、原料溶液の液面に対して所定の仰角をなすように形成され、この仰角は、原料溶液の液面に対して５゜以上で３０゜以下となるように形成することにより、適正な圧力で原料溶液を密閉容器内から溶液塗布部に供給することができることは、前述の本発明者等による発明と同様である。
【００２６】
図１は、本発明のテープ状酸化物超電導線の製造に用いる製造装置１の概略を示したもので、２は原料溶液塗布装置、３はテープ供給装置、４は保温チャンバ、６はテープ移動機構である。
【００２７】
図２に示すように、原料溶液塗布装置２は、内部に揮発性溶媒を用いた酸化物超電導物質の原料溶液８を収容するための密閉容器９と、この密閉容器の外部に形成された溶液塗布部１０及び密閉容器を貫通し一端側が原料溶液８の液面下に開口し他端側が溶液塗布部１０に開口する複数の細管１１とを備えている。密閉容器９内の原料溶液８の液面は、その高さを調整する原料溶液の補給機構（図示せず）により、その液面がほぼ一定に保持されている。複数の細管１１の内径、本数及び間隔は、原料溶液８を塗布するテープ状基材１２の幅、膜厚、原料溶液の濃度等により適宜決定される。
【００２８】
テープ供給装置３は、保温チャンバ４内に配設され、このテープ供給装置３（線材サプライ）全体を囲うチャンバーの加熱には、通常リボンヒーター等を巻きつけて実施することができるが、均一にチャンバー全体を加熱するためには、図１で示すように、チャンバーを２重構造とし、その間にオイル５を充填して、このオイルを加熱制御する方法が好ましい。
【００２９】
テープ移動機構６は、回転軸を中心として回転駆動される回転ローラからなり、連続的にテープ状基材12を移動せしめ、テープ供給装置３から引き出されたテープ状基材12を溶液塗布部10に供給して、その表面に原料溶液８を塗布する。原料溶液８が塗布されたテープ状基材12は、焼成ドラム７上にスパイラル条に巻取られ、次いで、別途熱処理炉（図示せず）内で焼成される。
【００３０】
上記の回転軸は、ギャップ調整機構（図示せず）により、溶液塗布部10に対して所定の間隔を維持することが可能な構造を有し、複数の細管11を通して密閉容器９内から溶液塗布部10に供給される原料溶液８によってテープ状基材12と溶液塗布部10との間に形成される液体メニスカス（液溜り）により、テープ状基材12の表面に塗膜が形成される。
【００３１】
TFAーMOD法においては、原料溶液の濃度等にもよるが、この液体メニスカスをテープ状基材12と溶液塗布部10との間隔を２ｍｍ未満に設定して形成することが好ましい。
【００３２】
テープ状基材表面の塗膜の膜厚は、基材の移動速度と原料溶液の性質によって決まるが、毛細管の流動抵抗により原料溶液の供給量が制限されるため、均一な膜厚を有する塗膜が得られる塗膜速度（基材の移動速度）を１ｍ/sに制限する必要がある。
【００３３】
【実施例】
以下本発明の一実施例について説明する。
【００３４】
実施例
図１及び図２に示す装置において、外径φ1.7mmのポリテトラフルオロエチレン樹脂により細管11を形成し、このチューブの６本を平行に配置して平面状に形成された溶液塗布部10に幅11.2mmに開口させた。この場合、液体メニスカスは上記の開口幅より若干広がるため、幅12mm程度のテープ状基材まで塗布可能である。
【００３５】
また、複数の細管11は、毛細管現象を利用して原料溶液８を密閉容器９内から溶液塗布部10に適正に供給するために、原料溶液８の液面に対して15゜の仰角をなすように形成した。
【００３６】
一方、密閉容器９は、ポリテトラフルオロエチレン樹脂ブロックの中央部を径φ40mm、深さ40mmの有底状に掘削し、Oリングを介して板状体により開口部を密閉して形成した。
【００３７】
上記の溶液塗布部10を密閉容器９にOリングを介して嵌め込み、溶液塗布部10の細管11の開口部に対向して回転ローラからなるテープ移動機構６を配設した。
【００３８】
テープ供給装置３は、保温チャンバ４内に配設され、チャンバーを２重構造とし、その間にオイル５を充填して、このオイルを100℃±10℃に加熱制御した。
【００３９】
テープ状基材12として、ハステロイテープ上にIBAD法（基材に対して斜め方向からイオンを照射しながら、基板上にターゲットから発生した粒子を堆積させる方法:Ion Beam Assisted Deposition）で成膜したZr₂Gd₂O₇の中間層を形成した幅６mm、厚さ0.2mmのテープを用いた。
【００４０】
まず、酸化物超電導物質の原料溶液８として、TFA−YBCO溶液（YBa₂Cu₃-TFA塩溶液）をメタノール溶液に混合し、溶液濃度を0.15mol/Lに調整した。その溶液を密閉容器９の内部に収容し、テープ状基材12上に10cm/minの塗布速度で塗布した。
【００４１】
次いで、大気中100℃で30分仮焼した直後に、上記の装置を用いて2度目のTFA−YBCO溶液の塗布を行った。この時の湿度は54%であった。
【００４２】
次いで、水蒸気を含んだ酸素雰囲気下において、400℃以下の温度で仮焼した後、このY-Ba-Cu前駆体膜テープを水蒸気を含んだアルゴン/酸素混合ガス中において800℃で熱処理を行い、膜厚１μmのYBCOテープを得た。
【００４３】
上記の400℃以下の仮焼後の仮焼膜の表面は、鏡面状態を示した。また、焼成後のYBCOテープのX線回折の結果、（006）面のピーク強度は20,000c.p.sを示し、優れた結晶性を示した。
【００４４】
比較例
最初の仮焼膜の形成後、大気中での100℃×30分の加熱を行なうことなく、他は実施例と同様の方法により、テープ状基材上に２回の塗布を施して膜厚１μm未満のYBCOテープを得た。
【００４５】
上記の400℃以下の仮焼後の仮焼膜の表面は、ゲル化した球状の微少な粒が生成し、鏡面状態は示さなかった。また、焼成後のYBCOテープのX線回折の結果、（006）面のピーク強度は4,000c.p.sを示し、結晶性は著しく低下した。
【００４６】
【発明の効果】
以上述べたように、本発明によるテープ状酸化物超電導線の製造方法及びその製造装置によれば、テープ状基材を所定温度に保持することにより、仮焼膜表面への水分子の吸着の影響を防止することができ、均一な膜厚を有する塗膜を安定して形成することができ、その後の熱処理によって得られるテープ状酸化物超電導線は、優れた結晶性を示し、電力機器等への応用に適する。
【図面の簡単な説明】
【図１】本発明のテープ状酸化物超電導線の製造装置の一実施例を示す概略図である。
【図２】本発明の原料溶液塗布装置の一実施例を示す概略断面図である。
【符号の説明】
1…テープ状酸化物超電導線の製造装置
2…原料溶液塗布装置
3…テープ供給装置
4…保温チャンバ
５…オイル
６…テープ移動機構
７…焼成ドラム
８…原料溶液
９…密閉容器
10…溶液塗布部
11…細管
12…テープ状基材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an oxide superconducting wire and an apparatus for manufacturing the same, and in particular, an organic material that forms a superconducting film on a substrate by applying a raw material solution using a highly volatile solvent to the substrate surface, followed by drying and baking. The present invention relates to a method for manufacturing a tape-shaped oxide superconducting wire having a uniform film thickness and characteristics and suitable for use in equipment such as a superconducting magnet and a superconducting cable in a metal coating pyrolysis (MOD) method, and a manufacturing apparatus therefor.
[0002]
[Prior art]
Rare earth 123-based oxide superconductors have better magnetic field characteristics at liquid nitrogen temperature than Bi-based superconductors, so it is possible to maintain a practical high critical current density (Jc). If practical use is successful, in addition to excellent characteristics in the high temperature range, it is possible to produce a method that does not use silver, which is a noble metal, and because liquid nitrogen can be used as a refrigerant, cooling efficiency will be several tens to several hundred times Since it improves, it is very advantageous economically. As a result, it is possible to use the superconducting wire even for devices that have not been applicable from the viewpoint of economic efficiency, and it is predicted that the use and market of the superconducting devices will be greatly expanded.
[0003]
The crystal system of rare earth 123 superconductor (especially Y-123 superconductor, molar ratio of Y: Ba: Cu = 1: 2: 3) is orthorhombic. In order to achieve this, it is required not only to align the CuO plane of the crystal but also to align the in-plane crystal orientation. The reason for this is that a slight misalignment generates twin grain boundaries and deteriorates the current-carrying characteristics.
[0004]
The production method for increasing the in-plane orientation of the crystal of the Y-123 superconductor and forming the wire while aligning the in-plane orientation is the same as the method for producing the thin film. That is, by forming an intermediate layer with improved in-plane orientation and orientation on a tape-shaped metal substrate, and using the crystal lattice of this intermediate layer as a template, the in-plane orientation of the Y-123 superconductor crystal The degree and direction can be improved.
[0005]
Furthermore, it has been found that the critical current density (Jc) of a superconductor depends on the crystallinity and surface smoothness of the intermediate layer, and its characteristics change greatly depending on the state of the underlying layer.
[0006]
The manufacturing technology of the biaxially oriented metal substrate in which the in-plane oriented intermediate layer is formed on the tape-shaped metal substrate is the SOE (Surface-Oxidation Epitaxy) method, ISD (Inclined substrate deposition) method, IBAD (Ion Beam Assisted Deposotion) method and RABiTS (Rolling Assisted Biaxially Textured Substrate) method are known. Many Y-123 superconducting wires with Jc exceeding ⁶ A / cm ² have been reported.
[0007]
Many of these methods employ a vapor phase method such as a PLD (Pulse Laser Deposition) method for both the intermediate layer and the superconducting layer.
[0008]
In recent years, the TFA-MOD method using a fluorine compound raw material has been proposed in the United States as a method for forming a superconducting layer without using a vapor phase method. It shows the same Jc value as the Y-based oxide superconductor thin film obtained by the vapor deposition method such as chemical vapor deposition, etc., and from the expectation for the cost reduction of the wire, the Y-based oxide superconductor is converted to the wire again. (See, for example, Non-Patent Document 1).
[0009]
In the above TFA-MOD method, a solution obtained by dissolving trifluoroacetate in an anhydrous methanol solvent is applied on an oriented metal substrate having an oxide intermediate layer formed on the surface, and then calcined and burned to oxidize. In order to prevent formation of nitrates that occur during heat treatment of ordinary organic acid salt pyrolysis method, organic acid salts containing F (trifluoroacetate) are used as starting materials. If a coating film can be continuously formed and fired on a long metal substrate, a Y-based oxide superconductor tape can be produced by a simpler method than the vapor phase method.
[0010]
However, the above TFA-MOD method uses anhydrous methanol as the solvent of the raw material solution, so the solvent is highly volatile, and the concentration of the solution changes significantly during the continuous coating process on a long metal substrate. Therefore, it is very difficult to form a coating film with a uniform thickness, and the raw material solution is highly hygroscopic and has the property of absorbing moisture in the air and gelling it. There is a problem in that the raw material solution is altered by being exposed to air for a period of time.
[0011]
Further, when the spray drying method or the like is employed, there is a problem that clogging occurs due to solidification at the tip of the ejection hole during a long continuous operation.
[0012]
In response to the above problems, the present inventors have invented a bead coating method using a sealed container and a capillary phenomenon, and solved these problems.
[0013]
In this method, a raw material solution of an oxide superconducting substance using a volatile solvent is accommodated in a sealed container having a solution application part formed outside, and continuously maintained at a predetermined interval with respect to the solution application part. Continuous movement on the surface of the tape-shaped substrate by moving the tape-shaped substrate and supplying the raw material solution to the solution application section through a plurality of capillaries to form a liquid meniscus between the solution application section and the tape-shaped substrate. A raw material solution is applied (see Japanese Patent Application No. 2001-342392).
[0014]
Furthermore, although there is a problem that the film thickness that can be applied at one time is thin, this coating thickness can be increased to more than 1 μm by adopting a multilayer coating method that repeats a plurality of application to calcination processes. It was.
[0015]
[Non-Patent Document 1]
Cryogenic Engineering Vol.35, No.11, November 25, 2000, p.517
[0016]
[Problems to be solved by the invention]
As described above, the significant change in the concentration of the solution and the alteration of the raw material solution during the continuous application process in the TFA-MOD method could be solved by adopting a bead coating method utilizing a closed vessel and capillary phenomenon. As a new problem, the surface layer of the calcined film was modified during the interval between calcining and coating in the multilayer coating method.
[0017]
That is, when a coating film is formed again by the TFA-MOD method on the film that has been applied and calcined once, the raw material solution gels and granulates immediately after coating, making it difficult to form a uniform coating film. It has been found that this is likely to occur. In particular, this phenomenon occurs frequently during rainy days and rainy seasons when the humidity is high from summer to summer, and does not occur during dry periods when humidity is low.
[0018]
This phenomenon will become a big problem in the future in the production of long superconducting wires that require uniform film thickness and characteristics.
[0019]
The present invention has been made to solve the above problems, and after applying a raw material solution using a highly volatile solvent to the surface of the substrate, it is baked to form a coating film having a uniform film thickness by the MOD method. It is an object of the present invention to provide a method for manufacturing a tape-shaped oxide superconducting wire that can be stably formed and a manufacturing apparatus therefor.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the method for producing a tape-shaped oxide superconducting wire of the present invention comprises:
A raw material solution of an oxide superconducting material using a volatile solvent is accommodated in a sealed container having a solution application part formed outside, and a tape-like substrate is continuously maintained at a predetermined interval with respect to the solution application part. The surface of the tape-shaped substrate is formed by moving the material and supplying the raw material solution to the solution coating unit through a plurality of thin tubes to form a liquid meniscus between the solution coating unit and the tape-shaped substrate. In the method of manufacturing an oxide superconducting wire by continuously applying a raw material solution to a base material solution, a tape-like base material in a tape supply device for supplying a tape-like base material to the solution application part is provided. It is characterized in that it is maintained in a temperature range of from ° C to 150 ° C.
[0021]
In order to achieve the above object, the tape-shaped oxide superconducting wire manufacturing apparatus of the present invention includes a sealed container for containing a raw material solution of an oxide superconducting material using a volatile solvent, A planar solution application part formed outside the container and a plurality of capillaries penetrating the sealed container and having one end opened below the surface of the raw material solution and the other end opened in the planar solution application part. Raw material solution coating apparatus, a tape moving mechanism for continuously moving the tape-shaped base material while maintaining a predetermined interval with respect to the solution coating section, and a tape supply device for supplying the tape-shaped base material to the solution coating section In the oxide superconducting wire manufacturing apparatus comprising: a means for holding the tape-shaped substrate in the tape supply device in a temperature range of 50 ° C to 150 ° C.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
In the method for producing a tape-shaped oxide superconducting wire of the present invention, a superconducting film is formed by the MOD method, but when performing multi-layer coating, conventionally, the wire supplied from the wire supply is in a state exposed to the atmosphere. Under high humidity environment, water molecules in the atmosphere are easily adsorbed on the surface of the calcined film. As the length of the wire becomes longer, the exposure time to the atmosphere becomes longer, so adsorbed water molecules increase and react with the raw material solution applied at the application port to cause gelation.
[0023]
In order to prevent the influence of adsorption of the water molecules on the surface of the calcined film, it is necessary to keep the tape-like substrate in the tape supply device at a predetermined temperature. For this reason, the entire wire supply is enclosed, and the wire is supplied to the coating port while being kept at 50 to 150 ° C. Since the coating is performed after the water molecules adsorbed on the surface are desorbed by this heat retention, the influence of the reaction between the solution and water molecules is prevented, and the gelation of the solution can be prevented. As the above temperature range, a range of 100 ° C. ± 10 ° C. is particularly preferable.
[0024]
The raw material solution in this case is preferably a solution made of a solution obtained by dissolving trifluoroacetate in which an element constituting an oxide superconducting substance is blended in a predetermined molar ratio in an anhydrous methanol solvent. Of course, oxide superconducting materials such as Nd, Sm, and Ho to which the method, particularly the TFA-MOD method can be applied, can also be used.
[0025]
In the tape-shaped oxide superconducting wire manufacturing apparatus of the present invention, the solution application part is detachably attached to the hermetic container, the solution application part is formed in a flat shape, and a plurality of capillaries open to the solution application part. Preferably, the plurality of capillaries form a predetermined elevation angle with respect to the liquid surface of the raw material solution in order to supply the raw material solution in the hermetic container to the solution application unit using capillary action. The elevation angle is 5 ° or more and 30 ° or less with respect to the liquid surface of the raw material solution, so that the raw material solution can be supplied from the inside of the sealed container to the solution application unit with an appropriate pressure. This is possible in the same manner as the invention by the present inventors.
[0026]
FIG. 1 shows an outline of a manufacturing apparatus 1 used for manufacturing a tape-shaped oxide superconducting wire according to the present invention. 2 is a raw material solution coating apparatus, 3 is a tape supply apparatus, 4 is a heat insulation chamber, and 6 is a tape transfer. Mechanism.
[0027]
As shown in FIG. 2, the raw material solution coating apparatus 2 includes a sealed container 9 for containing a raw material solution 8 of an oxide superconducting substance using a volatile solvent therein, and a solution formed outside the sealed container. A plurality of capillaries 11 that pass through the application unit 10 and the sealed container, have one end opened below the surface of the raw material solution 8 and the other end opened in the solution application unit 10 are provided. The liquid surface of the raw material solution 8 in the sealed container 9 is held substantially constant by a raw material solution replenishing mechanism (not shown) for adjusting the height thereof. The inner diameter, the number, and the interval of the plurality of thin tubes 11 are appropriately determined depending on the width, film thickness, concentration of the raw material solution, and the like of the tape-like substrate 12 on which the raw material solution 8 is applied.
[0028]
The tape supply device 3 is disposed in the heat insulation chamber 4, and heating of the chamber surrounding the entire tape supply device 3 (wire supply) can be usually performed by winding a ribbon heater or the like. In order to heat the entire chamber, as shown in FIG. 1, it is preferable to use a method in which the chamber has a double structure, oil 5 is filled between the chambers, and the oil is heated and controlled.
[0029]
The tape moving mechanism 6 is composed of a rotating roller that is driven to rotate about a rotation axis. The tape moving mechanism 6 continuously moves the tape-like base material 12, and the tape-like base material 12 drawn from the tape supply device 3 is moved to the solution application unit 10. And the raw material solution 8 is applied to the surface. The tape-shaped substrate 12 coated with the raw material solution 8 is wound on a spiral strip on a firing drum 7 and then fired in a separate heat treatment furnace (not shown).
[0030]
The rotating shaft has a structure capable of maintaining a predetermined distance from the solution application unit 10 by a gap adjusting mechanism (not shown), and applies the solution from the inside of the sealed container 9 through a plurality of thin tubes 11. A coating film is formed on the surface of the tape-shaped substrate 12 by a liquid meniscus (liquid reservoir) formed between the tape-shaped substrate 12 and the solution application unit 10 by the raw material solution 8 supplied to the unit 10.
[0031]
In the TFA-MOD method, although depending on the concentration of the raw material solution, the liquid meniscus is preferably formed with the distance between the tape-shaped substrate 12 and the solution application part 10 set to less than 2 mm.
[0032]
The film thickness of the coating film on the surface of the tape-shaped substrate is determined by the moving speed of the substrate and the properties of the raw material solution. However, since the supply amount of the raw material solution is limited by the flow resistance of the capillary, the coating film having a uniform film thickness is used. It is necessary to limit the coating speed (the moving speed of the substrate) at which the film is obtained to 1 m / s.
[0033]
【Example】
An embodiment of the present invention will be described below.
[0034]
EXAMPLE In the apparatus shown in FIG. 1 and FIG. 2, a solution application part formed by forming a thin tube 11 from polytetrafluoroethylene resin having an outer diameter of φ1.7 mm and arranging six of these tubes in parallel to form a flat surface 10 was opened to a width of 11.2 mm. In this case, since the liquid meniscus is slightly wider than the opening width, it can be applied to a tape-shaped substrate having a width of about 12 mm.
[0035]
Further, the plurality of capillaries 11 form an elevation angle of 15 ° with respect to the liquid surface of the raw material solution 8 in order to appropriately supply the raw material solution 8 from the inside of the sealed container 9 to the solution application unit 10 by utilizing capillary action. Formed as follows.
[0036]
On the other hand, the sealed container 9 was formed by excavating the center of a polytetrafluoroethylene resin block into a bottomed shape having a diameter of 40 mm and a depth of 40 mm, and sealing the opening with a plate-like body via an O-ring.
[0037]
The solution application unit 10 was fitted into the sealed container 9 via an O-ring, and a tape moving mechanism 6 composed of a rotating roller was disposed facing the opening of the thin tube 11 of the solution application unit 10.
[0038]
The tape supply device 3 was disposed in the heat insulation chamber 4 and had a double structure. The oil was filled between the chambers, and the oil was heated and controlled at 100 ° C. ± 10 ° C.
[0039]
As tape-like substrate 12, film was formed on Hastelloy tape by IBAD method (Method of depositing particles generated from target on substrate while irradiating ions from oblique direction to substrate: Ion Beam Assisted Deposition) A tape having a width of 6 mm and a thickness of 0.2 mm formed with an intermediate layer of Zr ₂ Gd ₂ O ₇ was used.
[0040]
First, a TFA-YBCO solution (YBa ₂ Cu ₃ -TFA salt solution) was mixed with a methanol solution as a raw material solution 8 of an oxide superconducting material, and the solution concentration was adjusted to 0.15 mol / L. The solution was accommodated in the sealed container 9 and applied onto the tape-like substrate 12 at a coating speed of 10 cm / min.
[0041]
Next, immediately after calcining at 100 ° C. for 30 minutes in the atmosphere, a second TFA-YBCO solution was applied using the above apparatus. The humidity at this time was 54%.
[0042]
Next, after calcining at a temperature of 400 ° C. or less in an oxygen atmosphere containing water vapor, the Y-Ba-Cu precursor film tape is heat treated at 800 ° C. in an argon / oxygen mixed gas containing water vapor. A YBCO tape with a film thickness of 1 μm was obtained.
[0043]
The surface of the calcined film after calcining at 400 ° C. or lower showed a mirror state. As a result of X-ray diffraction of the YBCO tape after firing, the (006) plane peak intensity was 20,000 cps, indicating excellent crystallinity.
[0044]
Comparative Example After the first calcined film was formed, the coating was performed twice on the tape-like substrate in the same manner as in the example, without heating at 100 ° C. for 30 minutes in the air. A YBCO tape having a thickness of less than 1 μm was obtained.
[0045]
On the surface of the calcined film after calcining at 400 ° C. or lower, fine gelled spherical particles were formed, and the mirror surface state was not shown. Further, as a result of X-ray diffraction of the YBCO tape after firing, the peak intensity on the (006) plane showed 4,000 cps, and the crystallinity was significantly lowered.
[0046]
【The invention's effect】
As described above, according to the method and apparatus for producing a tape-shaped oxide superconducting wire according to the present invention, water molecules are adsorbed onto the surface of the calcined film by maintaining the tape-shaped substrate at a predetermined temperature. The tape-shaped oxide superconducting wire obtained by subsequent heat treatment can prevent the influence, can stably form a coating film having a uniform film thickness, and exhibits excellent crystallinity, such as power equipment Suitable for application to.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic view showing one embodiment of a production apparatus for a tape-shaped oxide superconducting wire of the present invention.
FIG. 2 is a schematic sectional view showing an embodiment of the raw material solution coating apparatus of the present invention.
[Explanation of symbols]
1 ... Tape oxide superconducting wire manufacturing equipment
2 ... Raw material solution coating equipment
3… Tape feeder
4 ... Insulating chamber 5 ... Oil 6 ... Tape moving mechanism 7 ... Firing drum 8 ... Raw material solution 9 ... Sealed container
10… Solution application part
11 ... capillary
12… Tape substrate

Claims

A raw material solution of an oxide superconducting material using a volatile solvent is accommodated in a sealed container having a solution application part formed outside, and a tape-like substrate is continuously maintained at a predetermined interval with respect to the solution application part. The surface of the tape-shaped substrate is formed by moving the material and supplying the raw material solution to the solution coating unit through a plurality of thin tubes to form a liquid meniscus between the solution coating unit and the tape-shaped substrate. In the method of manufacturing an oxide superconducting wire by continuously applying a raw material solution to the substrate, and firing it, a tape-like substrate in a tape supply device for supplying a tape-like substrate to the solution application part is provided. A method for producing a tape-shaped oxide superconducting wire, characterized in that the temperature is maintained in a temperature range of from ° C to 150 ° C.

2. The tape-shaped oxide superconductor according to claim 1, wherein the raw material solution is a solution obtained by dissolving trifluoroacetate in which an element constituting the oxide superconducting substance is mixed in an anhydrous methanol solvent at a predetermined molar ratio. Wire manufacturing method.

2. The method for producing a tape-shaped oxide superconducting wire according to claim 1, wherein the tape-shaped substrate in the tape supply device is maintained in a temperature range of 100 [deg.] C. ± 10 [deg.] C.

An airtight container for containing a raw material solution of an oxide superconducting substance using a volatile solvent therein, a planar solution application part formed outside the airtight container, and one end side penetrating the airtight container, the raw material solution A raw material solution coating apparatus provided with a plurality of thin tubes opened below the liquid surface and having the other end opened to the planar solution coating section, and continuously taped with a predetermined distance from the solution coating section In an oxide superconducting wire manufacturing apparatus comprising a tape moving mechanism for moving a tape-like base material and a tape supply device for supplying the tape-like base material to the solution application unit, the tape-like base material in the tape supply device is at 50 ° C. An apparatus for producing a tape-shaped oxide superconducting wire, characterized by comprising means for maintaining a temperature range of ˜150 ° C.

5. The apparatus for producing a tape-shaped oxide superconducting wire according to claim 4, further comprising means for maintaining the tape-shaped substrate in the tape supply device in a temperature range of 100 ° C. ± 10 ° C.