JPH079066B2 - Coating agent for forming oxide-based superconducting film - Google Patents

Coating agent for forming oxide-based superconducting film

Info

Publication number
JPH079066B2
JPH079066B2 JP62210952A JP21095287A JPH079066B2 JP H079066 B2 JPH079066 B2 JP H079066B2 JP 62210952 A JP62210952 A JP 62210952A JP 21095287 A JP21095287 A JP 21095287A JP H079066 B2 JPH079066 B2 JP H079066B2
Authority
JP
Japan
Prior art keywords
film
coating agent
superconducting
oxide
alkoxide
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.)
Expired - Lifetime
Application number
JP62210952A
Other languages
Japanese (ja)
Other versions
JPS6455384A (en
Inventor
英興 内川
利夫 小林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Mitsubishi Electric Corp
Original Assignee
Mitsubishi Electric Corp
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Filing date
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Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to JP62210952A priority Critical patent/JPH079066B2/en
Publication of JPS6455384A publication Critical patent/JPS6455384A/en
Publication of JPH079066B2 publication Critical patent/JPH079066B2/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/02—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition
    • C23C18/12—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition characterised by the deposition of inorganic material other than metallic material
    • C23C18/1204—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by thermal decomposition characterised by the deposition of inorganic material other than metallic material inorganic material, e.g. non-oxide and non-metallic such as sulfides, nitrides based compounds
    • C23C18/1208—Oxides, e.g. ceramics
    • C23C18/1216—Metal oxides

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Chemically Coating (AREA)
  • Superconductor Devices And Manufacturing Methods Thereof (AREA)

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は酸化物系超電導膜形成用コーティング剤に関す
る。TECHNICAL FIELD The present invention relates to a coating agent for forming an oxide-based superconducting film.

［従来の技術］ 従来から知られている超電導材料としては金属系のもの
が最も一般的であり、その中でもNb3Geが23.2Kという最
高の超電導転移温度（臨界温度）を有するものであっ
た。[Prior Art] Among the conventionally known superconducting materials, metal-based materials are most common, and among them, Nb 3 Ge has the highest superconducting transition temperature (critical temperature) of 23.2K. .

一方、金属酸化物系超電導材料は一般に金属系のものよ
りも臨界温度が低く、最高の臨界温度を有するBaPb1-XB
iXO3でもせいぜい13K程度であった。On the other hand, metal oxide type superconducting material is generally critical temperature than that of the metal-based low, BaPb 1-X B having the highest critical temperature
The i X O 3 was about 13K at best.

ところが、最近臨界温度の高い酸化物系超電導材料とし
てLa-Sr-Cu-O系の材料（約40K）およびY-Ba-Cu-O系の材
料（約90K）が見出され、高温超電導材料開発ブームを
まきおこしている。However, recently, La-Sr-Cu-O-based materials (about 40K) and Y-Ba-Cu-O-based materials (about 90K) have been found as oxide-based superconducting materials with a high critical temperature. It is causing a development boom.

これら酸化物系超電導材料の製造方法としては、いわゆ
る環式（粉末）法と共沈法とが一般に広く行なわれてい
る。The so-called cyclic (powder) method and coprecipitation method are generally widely used as methods for producing these oxide-based superconducting materials.

乾式法は、La、Ｙ、Ba、Sr、Cuなどの酸化物や炭酸塩の
粉末試薬を乳鉢やミルを用いて機械的に混合したのち焼
成して、酸化物の焼結体をうるという方法である。The dry method is a method in which powdered reagents of oxides or carbonates such as La, Y, Ba, Sr, and Cu are mechanically mixed in a mortar or mill and then fired to obtain a sintered body of oxides. Is.

また共沈法は、上記のような各金属の硝酸塩を水溶媒と
混合し、均一に溶解させたのち、しゅう酸やアンモニア
などを添加してそれぞれの混合沈澱物を同時にうるとい
う方法である。The coprecipitation method is a method in which the above-mentioned nitrates of the respective metals are mixed with an aqueous solvent and uniformly dissolved, and then oxalic acid, ammonia and the like are added to simultaneously obtain respective mixed precipitates.

これらの方法によりえられる材料はいずれも成形用には
適するが、被膜の形成には使用しがたいのが実情であ
る。All of the materials obtained by these methods are suitable for molding, but in reality, they are difficult to use for forming a film.

しかし、超電導素子や超電導回路などへの利用という観
点からは、被膜状の超電導体をうる技術が重要であり、
酸化物系超電導膜をうる技術として、通常の薄膜形成方
法であるスパッタリング法、蒸着法、CVD法などが試み
られている。However, from the viewpoint of use in superconducting elements and superconducting circuits, etc., technology for obtaining film-shaped superconductors is important,
As a technique for obtaining an oxide-based superconducting film, a usual thin film forming method such as a sputtering method, a vapor deposition method, and a CVD method has been tried.

それらの中では、「ジャパニーズ・ジャーナル・オブ・
アプライド・フィジックス（Japanese Journal of Appl
ied Physics）,Vol 26,No.4,pL 410（1987）および同Vo
l 26,No.5pL 738（1987）」などに記載されているよう
に、スパッタリング法が最も一般的で広く行なわれてい
る。スパッタリング法は、ターゲットであるLa-Sr-Cu-O
系やY-Ba-Cu-O系などの焼結体をイオン化したArやArとO
2との混合ガスで衝撃して、加熱した基板上にそれらの
酸化物の薄膜を付着させ、ついで焼成することにより超
電導膜にするというものである。Among them, “Japanese Journal of
Applied Physics (Japanese Journal of Appl
ied Physics), Vol 26, No. 4, pL 410 (1987) and Vo
26, No. 5pL 738 (1987), etc., the sputtering method is the most common and widely used. The sputtering method is the target La-Sr-Cu-O
Ar or Ar and O ionized from a sintered body such as Y-Ba-Cu-O system
The superconducting film is formed by bombarding with a mixed gas of 2 and depositing a thin film of these oxides on the heated substrate, and then firing.

［発明が解決しようとする問題点］ しかしながら、従来のスパッタリング法では、真空系、
反応器、高周波電源とその制御装置、ガス流量コントロ
ーラなどを備えた高価で大規模な設備が必要で、しかも
一度乾式法や共沈法を経て高温で焼結した酸化物系超電
導材料からなるスパッタリングターゲットを用いねばな
らないという欠点がある。加えて、スパッタリング法に
より膜を形成すると、しばしば意図する組成からのずれ
を生じたり、比較的薄い膜しか形成できないために結晶
化しにくく、したがって形成された膜の超電導状態に転
移する臨界温度が低いことや臨界電流密度（臨界温度以
下での電流密度）を大きくとれないことなどの特性上の
問題がある。[Problems to be Solved by the Invention] However, in the conventional sputtering method,
Expensive and large-scale equipment equipped with a reactor, high-frequency power supply and its control device, gas flow controller, etc. is required, and sputtering consisting of oxide superconducting material once sintered at high temperature through dry method or coprecipitation method. It has the drawback of having to use a target. In addition, when a film is formed by a sputtering method, the composition often deviates from the intended composition, and it is difficult to crystallize because only a relatively thin film can be formed. Therefore, the formed film has a low critical temperature for transition to a superconducting state. There is a problem in characteristics such as the fact that the critical current density (current density below the critical temperature) cannot be made large.

本発明は前記のような問題点を解消するためになされた
ものである。The present invention has been made to solve the above problems.

［問題点を解決するための手段］ 本発明は、従来の方法に比べて非常に容易に膜を形成す
ることができ、形成された膜の超電導状態へ転移する臨
界温度が高く、その転移温度幅が狭く、かつ臨界電流密
度を大きくとれるなど、超電導特性の優れた酸化物系超
電導膜を形成することができ、かつ保存性に優れたコー
ティング剤を提供するためになされたものであり、Mg、
Ca、SrおよびBaから選ばれた１種以上の元素、Sc、Ｙお
よびランタノイドから選ばれた１種以上の元素ならびに
Cuそれぞれのアルコキシドの部分加水分解生成物がカル
ボン酸とともに有機溶媒中に均質に溶解、分散または懸
濁せしめられてなる酸化物系超電導膜形成用コーティン
グ剤に関する。[Means for Solving Problems] In the present invention, a film can be formed very easily as compared with a conventional method, and the formed film has a high critical temperature for transition to a superconducting state. It is made to provide a coating agent that can form an oxide-based superconducting film with excellent superconducting properties, such as a narrow width and a large critical current density, and has excellent storage stability. ,
One or more elements selected from Ca, Sr and Ba, one or more elements selected from Sc, Y and lanthanoid, and
The present invention relates to a coating agent for forming an oxide-based superconducting film in which a partial hydrolysis product of each alkoxide of Cu is homogeneously dissolved, dispersed or suspended in an organic solvent together with a carboxylic acid.

［作 用］ 本発明に用いる所定の金属元素のアルコキシドの部分加
水分解生成物は、カルボン酸とともに適当な有機溶媒中
に均質かつ安定に溶解、分散または懸濁せしめられう
る。それゆえ、この液をディッピング法、印刷法、ハケ
塗り法などの簡易な方法で基板などにコーティングして
焼成するだけで、容易に均質な酸化物系超電導膜がえら
れる。[Operation] The partial hydrolysis product of the alkoxide of a predetermined metal element used in the present invention can be homogeneously and stably dissolved, dispersed or suspended in a suitable organic solvent together with a carboxylic acid. Therefore, a homogeneous oxide-based superconducting film can be easily obtained only by coating the substrate or the like with this solution by a simple method such as a dipping method, a printing method, or a brush coating method and baking.

本発明のコーティング剤を塗布したのち焼成してえられ
る酸化物系超電導膜は、比較的厚いものであるため、従
来の薄膜形成法（たとえばスパッタリング法など）によ
る膜と比較して焼成時に結晶化しやすく、超電導膜がえ
られやすい。Since the oxide-based superconducting film obtained by applying the coating agent of the present invention and then baking is relatively thick, it is crystallized during baking as compared with a film formed by a conventional thin film forming method (for example, a sputtering method). It is easy to obtain a superconducting film.

［実施例］ 本発明においては、本発明に用いる金属（Mg、Ca、Sr、
Ba、Sc、Ｙ、ランタノイドおよびCu）のアルコキシドか
ら部分加水分解生成物が調製される。[Examples] In the present invention, the metals (Mg, Ca, Sr,
Partial hydrolysis products are prepared from alkoxides of Ba, Sc, Y, lanthanoids and Cu).

前記本発明に用いる金属のアルコキシドにはとくに限定
はなく、えられる部分加水分解生成物が使用する溶媒中
に均質に溶解、分散または懸濁せしめられ、焼成により
被覆にしうるものであるかぎり、いかなる構造、形態の
ものをも使用しうる。すなわち、前記金属アルコキシド
を形成するアルコキシ基の炭素数がいくつのものであっ
ても、また多価アルコールからのアルコキシドであって
も用いることができる。このようなアルコキシ基の好ま
しい具体例としては、たとえばメトキシ基、エトキシ
基、プロポキシ基、イソプロポキシ基、ブトキシ基、第
３級ブトキシ基、第２級ブトキシ基などがあげられるが
これらに限定されるものではない。The metal alkoxide used in the present invention is not particularly limited, as long as the obtained partial hydrolysis product is homogeneously dissolved, dispersed or suspended in the solvent used and can be coated by baking. Structures and forms can also be used. That is, any number of carbon atoms of the alkoxy group forming the metal alkoxide or an alkoxide from a polyhydric alcohol can be used. Preferred specific examples of such an alkoxy group include, but are not limited to, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, a tertiary butoxy group, and a secondary butoxy group. Not a thing.

本明細書にいう部分加水分解生成物とは、平均的にみて
金属アルコキシドを構成するアルコキシ基の0.3個以上
が加水分解し、0.1個以上のアルコキシ基が加水分解さ
れずに残存するものであり、通常前記金属アルコキシド
を有機溶媒中に溶解、分散または懸濁させ、制限された
量の水で加水分解することにより調製される。The partial hydrolysis product referred to in the present specification is one in which 0.3 or more of the alkoxy groups constituting the metal alkoxide on average are hydrolyzed, and 0.1 or more alkoxy groups remain without being hydrolyzed. Usually, it is prepared by dissolving, dispersing or suspending the metal alkoxide in an organic solvent and hydrolyzing it with a limited amount of water.

前記有機溶媒としては、たとえばメチルアルコール、エ
チルアルコール、イソプロピルアルコール、ブタノー
ル、イソアミルアルコール、ベンゼン、トルエン、キシ
レン、テトラヒドロフラン、ジエチルエーテル、ジフェ
ニルエーテル、アニソール、メチルエチルケトン、メチ
ルイソブチルケトン、酢酸エチル、酢酸ブチルなどの有
機溶媒が使用される。Examples of the organic solvent include organic solvents such as methyl alcohol, ethyl alcohol, isopropyl alcohol, butanol, isoamyl alcohol, benzene, toluene, xylene, tetrahydrofuran, diethyl ether, diphenyl ether, anisole, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate and butyl acetate. A solvent is used.

部分加水分解する際の水の量は、金属アルコキシドの加
水分解し易さなどによって大きく異なるが概ね金属アル
コキシドを完全に加水分解しうる化学量論量の50〜500
％程度が好ましく、加水分解する際の温度は室温〜80℃
であるのが好ましい。また、水の添加方法としては金属
アルコキシドの溶液、分散液または懸濁液に所定量の水
を加える方法が好ましい。添加される水としては、金属
イオンなどを含まないイオン交換水、蒸留水などが用い
られる。The amount of water used for partial hydrolysis greatly varies depending on the ease with which the metal alkoxide is hydrolyzed, but in general, the stoichiometric amount of 50 to 500, which can completely hydrolyze the metal alkoxide,
% Is preferable, and the temperature during hydrolysis is room temperature to 80 ° C.
Is preferred. As a method of adding water, a method of adding a predetermined amount of water to a solution, dispersion or suspension of metal alkoxide is preferable. As water to be added, ion-exchanged water containing no metal ions, distilled water, etc. are used.

加水分解する金属アルコキシドとしては、Mg、Ca、Srお
よびBaの中から選ばれた１種以上の元素、Sc、Ｙおよび
ランタノイドの中から選ばれた１種以上の元素ならびに
Cuの各元素を含有するアルコキシドを使用し、前記のご
とき条件で加水分解すると本発明に使用する所定の金属
アルコキシドの部分加水分解生成物を含有する溶液、分
散液、または懸濁液がえられる。The hydrolyzable metal alkoxide includes one or more elements selected from Mg, Ca, Sr and Ba, one or more elements selected from Sc, Y and lanthanoids, and
When an alkoxide containing each element of Cu is used and hydrolyzed under the conditions as described above, a solution, dispersion or suspension containing a partial hydrolysis product of a predetermined metal alkoxide used in the present invention can be obtained. .

このようにして部分加水分解生成物を含有する混合液を
調製すると、金属アルコキシドを完全に加水分解したば
あいにえられる水酸化物または酸化物などに比して有機
溶媒とのなじみがよくなり、有機溶媒中に溶解、分散ま
たは懸濁させやすくなる。また未加水分解物に比して溶
液の粘度が上昇するため、塗布膜を形成するのに都合が
よいというコーティング剤として好ましい特性を有する
ようになる。When a mixed solution containing a partially hydrolyzed product is prepared in this way, it becomes more compatible with organic solvents than the hydroxide or oxide obtained when the metal alkoxide is completely hydrolyzed. , Becomes easy to dissolve, disperse or suspend in an organic solvent. In addition, since the viscosity of the solution is higher than that of the unhydrolyzed product, it has favorable characteristics as a coating agent, which is convenient for forming a coating film.

前記部分加水分解生成物を含有するものを調製する際に
用いるMg、Ca、SrおよびBaから選ばれた１種以上の元素
を含むアルコシシド（以下、II a族系アルコキシドとい
う）、Sc、Ｙおよびランタノイドから選ばれた１種以上
の元素を含むアルコキシド（以下、III a族系アルコキ
シドという）ならびにCuアルコキシドを混合する割合に
はとくに限定はなく、目的とする酸化物系超電導膜を与
えるコーティング剤がえられるかぎりいかなる組成割合
で混合してもよいが、たとえばIII a族元素としてＹを
用いるばあいにはII a族系アルコキシド/Yアルコキシド
/Cuアルコキシド＝２〜10/1/3〜10（金属の原子比）程
度で混合するのが好ましく、またIII a族元素としてLa
を用いるばあいには（II a族系アルコキシド＋Laアルコ
キシド）/Cuアルコキシド＝2/1（金属の原子比）程度で
混合するのが好ましい。なおII a族系アルコキシドとLa
アルコキシドとの比率にはとくに限定はない。Alcosides containing one or more elements selected from Mg, Ca, Sr and Ba (hereinafter referred to as IIa group alkoxides), Sc, Y and used for preparing the one containing the partial hydrolysis product. There is no particular limitation on the mixing ratio of the alkoxide containing one or more elements selected from the lanthanoids (hereinafter referred to as IIIa group alkoxide) and the Cu alkoxide, and the coating agent that gives the target oxide-based superconducting film They may be mixed in any composition ratio as far as possible. For example, when Y is used as the group IIIa element, the group IIa alkoxide / Y alkoxide is used.
/ Cu alkoxide = 2 to 10/1/3 to 10 (atomic ratio of metal) is preferably mixed, and as a Group IIIa element is La
In the case of using, it is preferable to mix (IIa group alkoxide + La alkoxide) / Cu alkoxide = 2/1 (atomic ratio of metal). In addition, II a group alkoxide and La
The ratio with the alkoxide is not particularly limited.

えられた部分加水分解生成物を含有する混合液はこのま
までは一般にゲル化して固化しやすく、保存安定性が充
分でない。この理由は明確ではないが、部分加水分解生
成物中に存在する水酸基間で、脱水縮合がおこったりす
るためではないかと考えている。The mixed solution containing the obtained partial hydrolysis product generally gels and solidifies as it is, and the storage stability is not sufficient. The reason for this is not clear, but it is considered that dehydration condensation may occur between the hydroxyl groups present in the partial hydrolysis product.

ところがこの液にカルボン酸を加えるとゲル化しにくく
なり、保存安定性が良好（分散液や懸濁液が分離しない
ということではなく、たとえ分離しても混合したりする
だけで使用しうる状態になることをいう）になるととも
に、塗布性なども改善される。However, when carboxylic acid is added to this solution, it becomes difficult to gel, and storage stability is good (not that the dispersion or suspension does not separate, but even if it is separated, it can be used just by mixing them. That is, the coating property is improved.

前記添加するカルボン酸としては、たとえばギ酸、酢
酸、プロピオン酸、ブタン酸、しゅう酸、マレイン酸、
オクチル酸、オレイン酸などがあげられる。カルボン酸
以外の酸でもゲル化しにくくすることができるが、たと
えば酸に含まれるCl、Brなどがコーティング後の焼成膜
中にCl-、Br-などのイオンとして残存すると超電導特性
が低下したり、ばあいによっては部分加水分解生成物を
分解させ、超電導膜がえられなくなったりするために好
ましくない。Examples of the carboxylic acid to be added include formic acid, acetic acid, propionic acid, butanoic acid, oxalic acid, maleic acid,
Examples include octylic acid and oleic acid. Although it is possible to make gelation difficult even with acids other than carboxylic acid, for example, Cl, Br, etc. contained in the acid in the baked film after coating remain as ions such as Cl − , Br −, etc., or the superconducting property deteriorates, In some cases, the partial hydrolysis product is decomposed and the superconducting film cannot be obtained, which is not preferable.

前記カルボン酸の添加量としてはコーティング剤の全重
量に対して３〜20％程度が好ましく、５〜10％程度がさ
らに好ましい。The amount of the carboxylic acid added is preferably about 3 to 20%, more preferably about 5 to 10%, based on the total weight of the coating agent.

なお、えられるコーティング剤中には焼成後にえられる
超電導膜の特性をわるくしない範囲であれば、ほかの化
合物、たとえば界面活性剤、分散剤、乳化剤などを加え
てもよい。Other compounds such as a surfactant, a dispersant and an emulsifier may be added to the obtained coating agent as long as the characteristics of the superconducting film obtained after firing are not deteriorated.

本発明のコーティング剤には本発明に用いる金属の所定
の３種以上を含有する化合物がコーティング剤中に合計
３％（重量％、以下同様）以上含有されているのが好ま
しく、10〜30％含有されているのがさらに好ましい。The coating agent of the present invention preferably contains a compound containing at least three kinds of metals used in the present invention in a total amount of 3% (% by weight, the same applies hereinafter) or more, and 10 to 30%. More preferably, it is contained.

このようにしてえられる本発明のコーティング剤は、た
とえば淡黒色、茶色または黒かっ色のごとき色調で流動
性を有し、通常pH4〜５程度であり、製造後30日間以上
安定であり、塗布法、スプレー法、ディップ法、スクリ
ーン印刷法、スピンコーティング法などの方法で基体に
付着せしめたのち、乾燥、焼成（要すれば予備焼成を含
む）することにより、膜厚５〜50μｍ程度の酸化物系超
電導膜がえられる。The coating agent of the present invention thus obtained has fluidity with a color tone such as pale black, brown or blackish brown, usually has a pH of about 4 to 5, is stable for 30 days or more after production, and is applied by a coating method. An oxide with a film thickness of about 5 to 50 μm is obtained by applying it to a substrate by a method such as a spray method, a dip method, a screen printing method or a spin coating method, and then drying and baking (including preliminary baking if necessary). A superconducting film can be obtained.

塗膜の乾燥は、たとえば室温で10分間放置後120℃で20
分間のごとき条件で行ない、そののち要すれば約300〜5
00℃で約30〜60分間の予備焼成を行なったのち、約800
〜1000℃で約２〜５時間焼成することにより、酸化物系
超電導膜が製造される。The coating film can be dried, for example, by leaving it at room temperature for 10 minutes and then at 120 ° C for 20 minutes.
Do this under the condition of a minute, and if necessary, about 300-5
After pre-baking at 00 ℃ for about 30-60 minutes, then about 800
An oxide-based superconducting film is manufactured by baking at about 1000 ° C. for about 2 to 5 hours.

前記焼成を行なう際の雰囲気としては、空気中、酸素雰
囲気中いずれでもよく、また焼成プロセスは任意の温度
で任意の回数行なうことができる。本発明者らの検討に
よれば酸素が豊富な雰囲気中で行なった方が概して超電
導特性の良好な膜が製造できるようであった。これは、
酸素の豊富な雰囲気中で焼成すると、用いた各化合物が
熱分解したのち各金属元素の酸化物が生成しやすくなる
ことによるものと推察される。The atmosphere for performing the firing may be either air or oxygen atmosphere, and the firing process can be performed at any temperature and any number of times. According to the study by the present inventors, it seems that a film having excellent superconducting properties can be generally manufactured by carrying out in an atmosphere rich in oxygen. this is,
It is speculated that this is because, when firing in an atmosphere rich in oxygen, each compound used is thermally decomposed and then an oxide of each metal element is easily generated.

つぎに本発明のコーティング剤を実施例に基づき説明す
る。Next, the coating agent of the present invention will be described based on Examples.

実施例１および比較例１ 目的とする酸化物系超電導膜の組成が （La0.92Sr0.08）2CuO4となるようにLaブトキシド、Sr
ブトキシドならびにCuブトキシドをブタノール200ml中
に全重量の15％となるように均質に分散させた。Example 1 and Comparative Example 1 La butoxide and Sr were added so that the composition of the target oxide-based superconducting film was (La 0.92 Sr 0.08 ) 2 CuO 4.
Butoxide as well as Cu butoxide were homogeneously dispersed in 200 ml butanol to 15% of the total weight.

この分散液を60℃に調節したのち、イオン交換水3mlを1
0分間かけて滴下しながら部分加水分解を行ない、全金
属アルコキシドの約20モル％が加水分解された部分加水
分解生成物を含有する均質な混合液を調製した。この液
に酢酸10mlを加えて均一な液とした。After adjusting this dispersion to 60 ° C, add 3 ml of deionized water to 1
Partial hydrolysis was carried out while dropping for 0 minutes to prepare a homogeneous mixed solution containing a partial hydrolysis product in which about 20 mol% of all metal alkoxides were hydrolyzed. 10 ml of acetic acid was added to this liquid to make a uniform liquid.

えられた液は黒緑色、半透明で流動性があり、粘度は約
1500cPで、製造後30日間以上安定であった。この液を攪
拌しながらα‐Al2O3基板の片面にディップコーティン
グして室温および80℃で乾燥させたのち、酸素気流中、
915℃で３時間焼成し、α‐Al2O3基板上に厚さ約30μｍ
の焼成膜を形成した。The obtained liquid is black-green, semi-transparent and has fluidity, and the viscosity is about
At 1500 cP, it was stable for more than 30 days after production. After stirring this solution with dip coating on one side of the α-Al 2 O 3 substrate and drying at room temperature and 80 ° C, in an oxygen stream,
Baking at 915 ℃ for 3 hours, thickness of about 30μm on α-Al 2 O 3 substrate
The fired film of was formed.

比較のため、従来のスパッタリング法により乾式法で作
製したほぼ（La0.92Sr0.08）2CuO4の焼結体のターゲッ
トを用い、Ar（50mTorr）中、スパッタリング時間４時
間、基板（α‐Al2O3）温度400℃なる条件で厚さ0.5μ
ｍの薄膜を作製し、実施例１と同一条件（酸素気流中91
5℃、３時間）で焼成して焼結膜をえた。For comparison, a target of a (La 0.92 Sr 0.08 ) 2 CuO 4 sintered body prepared by a dry method by a conventional sputtering method was used, in Ar (50 mTorr), a sputtering time of 4 hours and a substrate (α-Al 2 O 3 ) 0.5μ thickness at 400 ℃
m under the same conditions as in Example 1 (in an oxygen stream 91
A sintered film was obtained by firing at 5 ° C. for 3 hours.

前記２種のサンプルにそれぞれインジウムを用いて1.5m
m間隔で４つの電極を形成してクライオスタット中に入
れ、液体ヘリウムで徐々に冷却しながら４端子法によっ
て各サンプルの抵抗率の温度変化を測定した。結果を第
１図に示す。1.5m each using indium for the two samples
Four electrodes were formed at m intervals and placed in a cryostat, and the temperature change of the resistivity of each sample was measured by the four-terminal method while gradually cooling with liquid helium. The results are shown in Fig. 1.

第１図において、曲線（Ａ）は本発明のコーティング剤
を用いた実施例１でえられた膜を特性、曲線（Ｂ）は従
来のスパッタリング法によりえられた膜の特性を示すグ
ラフである。In FIG. 1, curve (A) is a graph showing the characteristics of the film obtained in Example 1 using the coating agent of the present invention, and curve (B) is a graph showing the characteristics of the film obtained by the conventional sputtering method. .

第１図の結果から、本発明のコーティング剤からの酸化
物系超電導膜は、従来の方法によるものと比べると冷却
にともなって急激に抵抗率が０、すなわち超電導状態に
転移することがわかる。また、超電導状態（4.3K）にお
いて各サンプルへの印加電圧を上げることによって流れ
る電流値を徐々に上昇させ、超電導状態が破れて常電導
状態に移行する際の臨界電流密度を求めたところ、実施
例１でえられた膜は986A/cm2、比較例１でえられた膜は
76.2A/cm2であった。From the results shown in FIG. 1, it can be seen that the oxide-based superconducting film made of the coating agent of the present invention has a resistivity which is abruptly changed to 0, that is, a superconducting state, with cooling, as compared with the conventional method. In the superconducting state (4.3K), increasing the applied voltage to each sample gradually increased the flowing current value, and obtained the critical current density when the superconducting state was broken and the state changed to the normal conducting state. The film obtained in Example 1 was 986 A / cm 2 , and the film obtained in Comparative Example 1 was
It was 76.2 A / cm 2 .

以上の結果から、本発明のコーティング剤からの酸化物
系超電導膜は、従来の方法によるものと比べると抵抗率
が完全に０となる温度が高いばかりでなく、常電導状態
から超電導状態への転移幅が小さく、かつ臨界電流密度
がきわめて大きいという実用上きわめて有利な特性を有
するものであることがわかる。これに対して、従来の薄
膜製造方法であるスパッタリング法によるものは、転移
温度、転移幅、臨界電流密度のいずれも実用に供しえな
い不充分な特性しか有さないことがわかる。From the above results, the oxide-based superconducting film from the coating agent of the present invention has not only a high temperature at which the resistivity becomes completely 0, but also a normal-conducting state to a superconducting state as compared with the conventional method. It can be seen that the transition width is small and the critical current density is extremely large, which is extremely advantageous in practical use. On the other hand, it can be seen that the sputtering method, which is a conventional thin film manufacturing method, has insufficient properties such that the transition temperature, the transition width, and the critical current density cannot be put to practical use.

前記２種のサンプルについて、Ｘ線回折法などにより構
造解析を行なったところ、実施例１でえられた膜は、い
わゆるK2NiF4型のほぼ（La0.92Sr0.08）2CuO4のほぼ均
一な単相からなる焼結膜であることが判明した。一方、
従来のスパッタリング法による比較例１でえられた膜
は、前記K2NiF4型の相以外にABO3（Ａ、Ｂは金属元素）
型のペロブスカイト構造やそのほかの相が比較的多く混
在していることが判明した。とくに、目的とする組成か
らCuが欠損してしまう傾向が著しく、目的とする組成か
らの元素比のずれが著しくなることが明らかとなった。
すなわち、第１図に示したように従来の方法による酸化
物系超電導膜の特性が良好でない原因は、前記の組成的
なずれなどが影響していると考えられる。Structural analysis of the above-mentioned two kinds of samples by X-ray diffraction etc. revealed that the film obtained in Example 1 was almost uniform in so-called K 2 NiF 4 type (La 0.92 Sr 0.08 ) 2 CuO 4 . It was found to be a sintered film composed of a simple single phase. on the other hand,
The film obtained in Comparative Example 1 by the conventional sputtering method is ABO 3 (A and B are metallic elements) in addition to the K 2 NiF 4 type phase.
It was revealed that a relatively large amount of type perovskite structure and other phases are mixed. In particular, it became clear that Cu tends to be lost from the target composition, and the deviation of the element ratio from the target composition becomes remarkable.
That is, it is considered that the above compositional deviation or the like influences the reason why the characteristics of the oxide-based superconducting film by the conventional method are not good as shown in FIG.

本発明のコーティング剤を用いると、用いた各元素の化
合物は焼成時に熱分解され、金属酸化物が生成するが、
熱分解の際に各金属元素が消失して欠損することはな
い。When the coating agent of the present invention is used, the compound of each element used is thermally decomposed during firing to generate a metal oxide,
Each metal element is not lost and lost during the thermal decomposition.

また、本発明のコーティング剤による超電導膜では、ス
パッタリング法や蒸着法などと比べると容易に厚膜が形
成できるため、焼成時に膜の結晶化が進行しやすいもの
と考えられる。Further, in the superconducting film of the coating agent of the present invention, a thick film can be easily formed as compared with the sputtering method, the vapor deposition method, etc., and it is considered that the crystallization of the film is likely to proceed during firing.

なお、実施例１で調製した部分加水分解生成物を含有す
る混合液に酢酸を加えずに１週間室内に放置したとこ
ろ、混合液はゲル化して寒天状となり、コーティング剤
として使用することはできなかった。In addition, when the mixed solution containing the partially hydrolyzed product prepared in Example 1 was allowed to stand in the room for 1 week without adding acetic acid, the mixed solution gelled into an agar-like form and could not be used as a coating agent. There wasn't.

実施例２および比較例２ 目的とする酸化物系超電導膜の組成がYBa2Cu3O7となる
ように、Ｙイソプロポキシド、Baイソプロポキシドおよ
び銅ブトキシドをイソプロピルアルコール300ml中に全
重量の10％となるように均質に分散させた。Example 2 and Comparative Example 2 Y isopropoxide, Ba isopropoxide and copper butoxide were added to 300 ml of isopropyl alcohol so that the composition of the target oxide-based superconducting film was YBa 2 Cu 3 O 7 . It was dispersed homogeneously so as to be 10%.

この分散液を70℃に調節したのち、イオン交換水4.5ml
を15分間かけて滴下しながら部分加水分解を行ない、金
属アルコキシドの約40モル％が加水分解された部分加水
分解生成物を含有する均質な混合液を調製した。この液
にマレイン膜25mlを加えて均一な液とした。After adjusting this dispersion to 70 ° C, 4.5 ml of deionized water
Was added dropwise over 15 minutes to carry out partial hydrolysis to prepare a homogeneous mixed solution containing a partial hydrolysis product in which about 40 mol% of the metal alkoxide was hydrolyzed. 25 ml of a malein film was added to this solution to make a uniform solution.

えられた液は黒緑色、半透明で流動性があり、粘度は約
900cPで、製造後30日間以上安定であった。The obtained liquid is black-green, semi-transparent and has fluidity, and the viscosity is about
At 900 cP, it was stable for more than 30 days after production.

えられた液を攪拌しながらZrO2（Y2O3安定化）基板の片
面にディップコーティングして室温および100℃で乾燥
させたのち、酸素気流中、960℃で2.5時間焼成し、ZrO2
基板上に厚さ約20μｍの焼結膜を形成した。While stirring the obtained solution, one side of the ZrO 2 (Y 2 O 3 stabilized) substrate was dip-coated, dried at room temperature and 100 ° C, and then calcined at 960 ° C for 2.5 hours in an oxygen stream to obtain ZrO 2
A sintered film having a thickness of about 20 μm was formed on the substrate.

比較のため、従来のスパッタリング法により乾式法で製
作したほぼYBa2Cu3O7の焼結体のターゲットを用い、Ar
（50mTorr）中、スパッタリング時間５時間、基板（ZrO
2）温度380℃なる条件で厚さ0.5μｍの薄膜を作製し、
実施例２と同一条件（酸素気流中960℃、2.5時間）で焼
成して焼結膜をえた。For comparison, using a target of a sintered body of almost YBa 2 Cu 3 O 7 produced by a dry method by a conventional sputtering method, Ar was used.
Sputtering time 5 hours in (50mTorr) substrate (ZrO
2 ) Prepare a thin film with a thickness of 0.5 μm under the condition that the temperature is 380 ° C.
A sintered film was obtained by firing under the same conditions as in Example 2 (960 ° C. in oxygen flow, 2.5 hours).

前記２種のサンプルについて実施例１と同様の方法で抵
抗率の温度変化および液体ヘリウム温度（4.3K）におけ
る臨界電流密度を測定した。結果を第２図に示す。With respect to the above two kinds of samples, the temperature change of the resistivity and the critical current density at the liquid helium temperature (4.3 K) were measured by the same method as in Example 1. Results are shown in FIG.

第２図において、曲線（Ｃ）は本発明のコーティング剤
を用いた実施例２でえられた膜の特性、曲線（Ｄ）は従
来のスパッタリング法によりえられた膜の特性を示すグ
ラフである。In FIG. 2, curve (C) is a graph showing the characteristics of the film obtained in Example 2 using the coating agent of the present invention, and curve (D) is a graph showing the characteristics of the film obtained by the conventional sputtering method. .

臨界電流密度は実施例２でえられたものが1635A/cm2、
比較例２でえられたものが113.1A/cm2であった。The critical current density obtained in Example 2 is 1635 A / cm 2 ,
The value obtained in Comparative Example 2 was 113.1 A / cm 2 .

これらの結果から、本発明のコーティング剤からの酸化
物系超電導膜は従来の方法によるものと比べると超電導
状態を示す臨界温度が高く、転移幅が狭く、かつ臨界電
流密度がきわめて大きいという実用上きわめてすぐれた
超電導特性を有することがわかる。これに対して従来の
方法による膜は臨界温度、転移幅、臨界電流密度のいず
れも実用に供しえない不充分な特性しか有さないもので
あることがわかる。From these results, the oxide-based superconducting film from the coating agent of the present invention has a high critical temperature showing a superconducting state, a narrow transition width, and an extremely large critical current density in practical use as compared with the conventional method. It can be seen that it has excellent superconducting properties. On the other hand, it can be seen that the film obtained by the conventional method has insufficient characteristics such that the critical temperature, the transition width and the critical current density cannot be put to practical use.

従来の方法による酸化物系超電導膜が良好な特性を有さ
ない理由としては、実施例１と同様の分析から、高温超
電導相以外の相を比較的多く含有することによることが
わかった。The reason why the conventional oxide-based superconducting film does not have good characteristics was found from the same analysis as in Example 1 because it contained a relatively large amount of phases other than the high temperature superconducting phase.

なお、実施例２で調製した部分加水分解生成物を含有す
る混合液にマレイン酸を加えずに72時間室内に放置した
ところ液は非常に高粘度のゲル状物となり、コーティン
グ剤として使用することはできなかった。In addition, when the mixed solution containing the partially hydrolyzed product prepared in Example 2 was left in the room for 72 hours without adding maleic acid, the solution became a gel having a very high viscosity and should be used as a coating agent. I couldn't.

［発明の効果］ 本発明のコーティング剤を用いて酸化物系超電導膜を形
成すると、臨界温度が高く、臨界電流密度の大きい超電
導膜が簡便な方法で容易にえられる。[Effect of the Invention] When an oxide superconducting film is formed using the coating agent of the present invention, a superconducting film having a high critical temperature and a large critical current density can be easily obtained by a simple method.

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

第１図ならびに第２図は、それぞれ本発明の実施例１お
よび比較例１ならびに実施例２および比較例２でえられ
た酸化物系超電導膜の抵抗率と温度との関係を示すグラ
フである。1 and 2 are graphs showing the relationship between the resistivity and the temperature of the oxide-based superconducting films obtained in Example 1 and Comparative Example 1 and Example 2 and Comparative Example 2 of the present invention, respectively. .

Claims (1)

【特許請求の範囲】[Claims] 【請求項１】Mg、Ca、SrおよびBaから選ばれた１種以上
の元素、Sc、Ｙおよびランタノイドから選ばれた１種以
上の元素ならびにCuそれぞれのアルコキシドの部分加水
分解生成物がカルボン酸とともに有機溶媒中に均質に溶
解、分散または懸濁せしめられてなる酸化物系超電導膜
形成用コーティング剤。1. A partial hydrolysis product of one or more elements selected from Mg, Ca, Sr and Ba, one or more elements selected from Sc, Y and lanthanoids and Cu alkoxides are carboxylic acids. A coating agent for forming an oxide-based superconducting film which is homogeneously dissolved, dispersed or suspended in an organic solvent together with.
JP62210952A 1987-08-24 1987-08-24 Coating agent for forming oxide-based superconducting film Expired - Lifetime JPH079066B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP62210952A JPH079066B2 (en) 1987-08-24 1987-08-24 Coating agent for forming oxide-based superconducting film

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP62210952A JPH079066B2 (en) 1987-08-24 1987-08-24 Coating agent for forming oxide-based superconducting film

Publications (2)

Publication Number Publication Date
JPS6455384A JPS6455384A (en) 1989-03-02
JPH079066B2 true JPH079066B2 (en) 1995-02-01

Family

ID=16597821

Family Applications (1)

Application Number Title Priority Date Filing Date
JP62210952A Expired - Lifetime JPH079066B2 (en) 1987-08-24 1987-08-24 Coating agent for forming oxide-based superconducting film

Country Status (1)

Country Link
JP (1) JPH079066B2 (en)

Also Published As

Publication number Publication date
JPS6455384A (en) 1989-03-02

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