JP3616243B2 - Electrochemical vapor deposition apparatus and solid electrolyte film forming method using the same - Google Patents

Description

この改質反応で発生する水素に対して、固体電解質１１３を介して対極する燃料極１１２と空気極１１４との部分で次の化２式の発電反応を起こし、遊離した電子を集電することによって発電力を得る。
【０００７】
【化２】

つまり、燃料極１１２においては化２（ａ）式に示すように、改質反応で生成された水素が、固体電解質１１３から供給される酸化物イオンと反応して水蒸気と電子を生成する。そして燃料極１１２で生成された電子が導電性フェルト１１５と導電性チューブ１１１を経て陰極１１８から外部回路に回り、陽極１１９を経て空気極１１４に到達すると、この空気極１１４において、化２（ｂ）式に示すように空気１１７中の酸素と反応して酸化物イオンを生成し、これが固体電解質１１３に放出され、燃料極１１２側に到達して化２（ａ）式の反応に供されるのである。
【０００８】
このような発電機構の燃料電池１１０において、空気極１１４、固体電解質１１３及び燃料極１１２の部分は次にようにして形成している。まず空気極１１４となるランタンマンガナイト系の多孔質の基材に対して電気化学蒸着法、つまり、ＣＶＤ（Ｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ ）−ＥＶＤ（Ｅｌｅｃｔｒｏｃｈｅｍｉｃａｌ Ｖａｐｏｒ Ｄｅｐｏｓｉｔｉｏｎ ）法を用いて薄く、かつ緻密なＹＳＺ膜を固体電解質１１３として形成し、さらにこのＹＳＺ膜にニッケル、コバルト、ニッケル又はコバルトを主成分とする合金、あるいはニッケルジルコニアサーメットの粉末をスラリーコートし、同じように電気化学蒸着法を施して多孔質の燃料極１１２を成膜し、あるいは特開平４−３４９３４３号公報に掲載されているような溶射法を用いて成膜するのである。
【０００９】
そして固体電解質１１３の成膜を行う電気化学蒸着装置としては、図６に示す構造のものが使用されている。この従来の電気化学蒸着装置は、反応室２１内を真空に近い状態、約１Ｔｏｒｒにして、かつヒータ２２によって約１０００〜１２００℃の温度条件下で、空気極支持管となる多孔質のストロンチウム添加ランタンマンガナイト（ＬＳＭ）製の基体２３の外側にはアルゴンＡｒ、酸素Ｏ_２ 、水蒸気Ｈ_２ Ｏの混合酸化ガス２４を導入し、他側面にはＹＳＺ膜の原料となるイットリウム、ジルコニウムの塩化物ＹＣｌ_３ ，ＺｒＣｌ_４ の蒸気２５をキャリアガスであるアルゴン（Ａｒ）ガスに混入して原料蒸気供給管２６から供給する。
【００１０】
この原料蒸気２５の供給系統は、塩化イットリウムＹＣｌ_３ 、塩化ジルコニウムＺｒＣｌ_４ の原料微粉末をパウダーフィーダ（ＭＰＦ）３１，３２に貯溜しておき、マスフローコントローラ（ＭＦＣ）３３，３４によって所定の流量でアルゴンキャリアガス３５を供給することによってキャリアガス３５に原料微粉末を混入しつつ配管３６を通じて反応室２１の原料蒸気供給管２６まで供給し、この原料蒸気供給管２６内でヒータ２２の加熱によって気化し、原料蒸気２５にして反応室２１内に供給する構造である。
【００１１】
このような構造の電気化学蒸着装置を使用することによって、図７（ａ）に示すように、最初は基体２３の多数の孔２７を通ってくる酸化ガス２４と原料蒸気２５とが化３式に示す反応をして図７（ｂ）に示すようにＹＳＺ膜２８を基体２３の表面に生成し、徐々に基体２３の多数の孔２７を閉塞していく。これがＣＶＤ段階である。
【００１２】
【化３】

このＣＶＤ段階が終了すると、原料蒸気２５と酸化ガス２４とは直接に反応することはなくなり、酸化ガス２４からの酸素がＹＳＺ面上で還元されてＹＳＺ膜２８中を酸化物イオンＯ^２−として拡散し、化４式に示す反応を原料塩化物蒸気と行うＥＶＤ段階へ進み、同図（ｃ）に示すようにＹＳＺ膜２８が成長する。
【００１３】
【化４】

こうして電気化学蒸着法によって固体電解質１１３としてＹＳＺ膜２８を成膜した後は、さらに上述した燃料極１１２をスラリーコーティングした後に電気化学蒸着する方法、その他の方法で燃料電池を作製することになる。
【００１４】
【発明が解決しようとする課題】
しかしながら、このような従来の電気化学蒸着装置の場合、次のような問題点があった。すなわち、図６に示すように原料蒸気供給管２６の下端開口部から原料蒸気２５を基体２３内に吐出し、基体２３の外側に酸化ガスを供給し、ＥＶＤ−ＣＶＤ反応で発生する塩化物排気４１、酸化物排気４２はそれぞれ、反応炉２１の上部に一個所ずつ設けられた排出口４３，４４を通じて外部に排出する構造であったため、反応炉２１内各部でガスの流れに速度差が生じやすく、これが基体２３の表面に蒸着する固体電解質２８の膜厚を不均一にする問題点があった。
【００１５】
本発明はこのような従来の問題点に鑑みてなされたもので、電気化学蒸着の実施中に基体を回転させると共に軸方向に移動させることによって固体電解質の膜厚を一様にすることができる電気化学蒸着装置及びそれを用いた固体電解質の成膜方法を提供することを目的とする。
【００１６】
【課題を解決するための手段】
請求項１の発明は、円管状の蒸着基体を内部に収容し、かつ気化された蒸着原料蒸気を蒸気導入管を通じて前記蒸着基体の内部に導入し、かつ前記蒸着基体の外部に酸化ガスを導入して、前記蒸着基体の内周面に電気化学蒸着膜を形成する反応室を備えて成る電気化学蒸着装置において、前記蒸着基体を軸周りに回転させる回転手段と、前記蒸着基体を軸方向に移動させる移動手段とを備えたものである。
【００１７】
請求項１の発明の電気化学蒸着装置では、蒸着原料粉末を高温で気化させ、反応室に導入して蒸着基体の内周面に電気化学蒸着させる際に、蒸着基体を軸周りに回転させ、かつ軸方向に移動させることによって、反応室内の蒸着原料蒸気の流れや酸化ガスの流れが不均一であっても蒸着基体の表面各所に均一な膜厚で原料蒸気を蒸着させ、膜厚の均一な固体電解質を成膜する。
【００１８】
請求項２の発明は、請求項１に記載された電気化学蒸着装置を用いた固体電解質の成膜方法であって、塩化イットリウム粉末、塩化ジルコニウム粉末それぞれを所定の割合、所定の流量で導出し、高温雰囲気で気化させて蒸着原料蒸気を生成し、この蒸着原料蒸気を前記反応室の前記蒸気導入管に導入して前記蒸着基体を軸周りに回転させ、かつ軸方向に移動させながらその内周面に電気化学蒸着膜を形成するものである。
【００１９】
請求項２の発明の固体電解質の成膜方法では、請求項１の電気化学蒸着装置を用いて蒸着基体の内周面に固体電解質膜を成膜するので、蒸着基体の内周面全体に渡り、均一な膜厚の固体電解質膜を成膜することができる。
【００２０】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて詳説する。図１及び図２は、本発明の１つの実施の形態の電気化学蒸着装置を示している。この第１の実施の形態の電気化学蒸着装置は、図６に示した従来例と同様に反応室２１内を真空に近い状態、約１Ｔｏｒｒにして、かつヒータ２２によって約１０００〜１２００℃の温度条件下で、空気極支持管となる多孔質のＬＳＭ基体２３の外側にはアルゴンＡｒ、酸素Ｏ_２ 、水蒸気Ｈ_２ Ｏの混合酸化ガス２４を導入し、内側にはＹＳＺ膜の原料となるイットリウム、ジルコニウムの塩化物ＹＣｌ_３ ，ＺｒＣｌ_４ の蒸気２５をキャリアガスであるアルゴン（Ａｒ）ガスに混入して原料蒸気供給管２６から供給する構成である。また原料蒸気２５の供給系統は、塩化イットリウムＹＣｌ_３ 、塩化ジルコニウムＺｒＣｌ_４ の原料微粉末をパウダーフィーダ（ＭＰＦ）３１，３２に貯溜しておき、マスフローコントローラ（ＭＦＣ）３３，３４によって所定の流量でアルゴンキャリアガス３５を供給することによってキャリアガス３５に原料微粉末を混入しつつ配管３６を通じて反応室２１の原料蒸気供給管２６まで供給し、この原料蒸気供給管２６内でヒータ２２の加熱によって気化し、原料蒸気２５にして反応室２１内に供給する構成である。
【００２１】
そして外部固定部材（図示せず）に固定されたスライドベース５１に係合されたスライダ５２によって上下垂直方向にスライド自在にモータ５３が支持されており、このモータ５３の回転出力軸５４に回転ねじ体５５が垂直軸の周りに水平に回転するように固定されている。回転ねじ体５５の下面側には締付けリング５６によってＬＳＭ基体２３の上端部が固定されている。なお、ＬＳＭ基体２３の上部（固体電解質膜を成膜しない部分）には後述する塩化物排気を排出するための通気口２３ａが複数箇所に形成されているものとする。
【００２２】
一方、上部に雌ねじ部６１が形成され、下部に追うＯリング６２のはめ込まれたスライドガイド６３が形成された支持筒体６４が反応室２１の上端部に固定されている。また支持筒体６４には複数の位置に塩化物排気用の通気口６５が形成されている。そしてこの支持筒体６４の雌ねじ部６１に前述の回転ねじ体５５が螺合させられている。
【００２３】
支持筒体６４よりも下方の位置において、反応室２１の内部に仕切板７１が気密的に取り付けられている。この仕切板７１の内周部にはＯリング７２がはめ込まれ、ＬＳＭ基体２３の外周面に気密的に、かつスライド可能に接触させられている。そしてこの仕切板７１の上側の位置において反応室２１に塩化物排気用の排気口７３が形成され、また仕切板７１の下側の位置において反応室２１に酸化物排気用の排気口７４が形成されている。
【００２４】
なお、原料蒸気供給管２６はモータ５３、回転出力軸５４、回転ねじ体５５及び締付けリング５６の各中心部を貫通するように配管されており、シーリング手段（図示せず）によって気密的にシーリングされていて、これらモータ５３、回転出力軸５４、回転ねじ体５５及び締付けリング５６が原料蒸気供給管２６に対して気密的に回転、スライドできるようにしてある。
【００２５】
次に、上記構成の電気化学蒸着装置による固体電解質成膜の手順について説明する。塩化イットリウムＹＣｌ_３ 、塩化ジルコニアＺｒＣｌ_４ の原料微粉末をパウダーフィーダ（ＭＰＦ）３１，３２に貯留しておき、マスフローコントローラ（ＭＦＣ）３３，３４によって所定の流量でアルゴンキャリアガス３５を供給することによってキャリアガス３５に原料微粉末が混入した原料（例えば、ＺｒＣｌ_４ ：ＹＣｌ_３ ＝５：１の重量比に混合）を配管３６を通じて原料蒸気供給管２６に４〜１０ｇ／ｈｒ程度の速度で供給し、ヒータ２２の加熱によって原料を気化させ、原料蒸気にして反応室２１内のＬＳＭ基体２３の内側に下部から供給する。
【００２６】
反応室２１内は真空に近い状態、約１Ｔｏｒｒにして、かつヒータ２２によって約１０００〜１２００℃の温度条件で、空気極支持管となる多孔質のＬＳＭ基体２３の外側にはアルゴンＡｒ、酸素Ｏ_２ 、水蒸気Ｈ_２ Ｏの混合酸化ガス２４を０．４〜２．０リットル／ｍｉｎ の流量で導入し、内側にはＹＳＺ膜の原料となるイットリウム、ジルコニウムの塩化物ＹＣｌ_３ ，ＺＣｌ_４ の蒸気２５をキャリアガスであるアルゴンＡｒに混入して原料蒸気供給管２６の下端部から供給する。これによって、図７に示したＣＶＤ−ＥＶＤ作用によって基体２３の内側面に固体電解質膜としてＹＳＺ膜２８が成膜される。
【００２７】
そしてこの原料蒸気２５の供給中、モータ５３を正逆回転させ、回転出力軸５４を介して回転ねじ体５５をゆっくりと正逆回転させることによって、反応室２１の上部の支持筒体６４の雌ねじ部１との螺合により回転ねじ体５５を回転させながらモータ５３と共に上下移動させ、これに取り付けられている基体２３をも回転させながら上下移動させる。基体２３の回転速度は０．００５〜０．０５ｒｐｍの微速である。これによって、原料蒸気２５の速度、濃度、反応室２１内の温度条件などのばらつきや中心軸のオフセットがあってもＹＳＺ膜２８が基体２３の内側面の各部に均一な膜厚で蒸着される。
【００２８】
なお、ＣＶＤ−ＥＶＤ法で生まれる塩化物排気４１は基体２３上部の通気口２３ａ、支持筒体６４の通気口６５を通じて反応室２１内の仕切板７１の上側の部屋に集まり、ここから排気口７３を通じて外部に排出される。また酸化物排気４２は反応室２１内の仕切板７２の下側に集まり、ここから排気口７４を通じて外部に排出される。
【００２９】
このようにしてこの第１の実施の形態の電気化学蒸着装置を用いた固体電解質成膜方法では、ＣＶＤ−ＥＶＤ法に基体２３に固体電解質ＹＳＺ膜２８を成膜する際に、基体２３を反応室２１内で回転させながら上下に移動させるので、反応室２１内の上下で、また円周方向で原料蒸気２５の速度、濃度、温度条件などのばらつきがあっても、ＹＳＺ膜２８が基体２３の内側面の各部に均一な膜厚で蒸着できる。
【００３０】
次に、本発明の第２の実施の形態の電気化学蒸着装置を図３に基づいて説明する。第２の実施の形態の電気化学蒸着装置は、原料液貯留部８１，８２を備え、原料微粉末である塩化イットリウムＹＣｌ_３ と塩化ジルコニウムＺｒＣｌ_４ それぞれを希釈剤としてのエタノールによって希釈して混合液にしてここに一時的に貯留する。この原料液貯留部８１，８２に貯留される原料液はマスフローコントローラ（ＭＦＣ）８３，８４それぞれによって一定時間に一定量を排出するように制御する。
【００３１】
反応室２１の構造と反応室２１内の基体２３に対する回転、スライド機構の構造は図１、図２に示した第１の実施の形態と同じである。
【００３２】
次に、この第２の実施の形態の電気化学蒸着装置を用いた固体電解質成膜の手順について説明する。塩化イットリウムと塩化ジルコニウムとの微粉末それぞれを適当な量のエタノールと混合して原料混合液を作成し、これらを原料液貯留部８１，８２それぞれに貯留させる。
【００３３】
反応室２１は真空に近い気圧、約１Ｔｏｒｒ程度まで減圧し、さらにヒータ２２によって１０００〜１２００℃の温度まで加熱する。そしてアルゴン、水蒸気及び酸素の混合酸化ガス２４を０．４〜２．０リットル／ｍｉｎ の流量で反応室２１内の基体２３の外側に供給する。
【００３４】
こうした予備工程の後、原料貯留部８１，８２に貯留されている原料液に対して、マスフローコントローラ８３，８４によってアルゴンガスを所定流量で供給してこれらの原料液を、例えば、両方の原料液の供給量がその中に含まれる原料粉末の重量に換算して合計で４〜１０ｇ／ｈｒ程度の流量で供給し、図示していない気化室で加熱して希釈剤を蒸発分解させ、さらに残った塩化イットリウム、塩化ジルコニウムを気化させた後、キャリアガスであるアルゴンガスＡｒと共に原料蒸気供給管２６に供給し、この原料蒸気供給管２６から原料蒸気２５を反応室２１内のＬＳＭ基体２３の内側に下部から供給する。
【００３５】
そしてこの原料蒸気２５の供給中、モータ５３を回転させ、回転出力軸５４を介して回転ねじ体５５をゆっくりと回転させることによって、回転ねじ体５５と共に基体２３を回転させながら上下移動させる。
【００３６】
この手順を所定時間、例えば５時間継続することにより、第１の実施の形態と同様にＣＶＤ−ＥＶＤ作用によって基体２３の内側面に固体電解質膜としてＹＳＺ膜２８を成膜することができる。しかも、原料蒸気２５の速度、濃度、反応室２１内の温度条件などのばらつきがあっても、基体２３が回転しながら上下移動するのでＹＳＺ膜２８を基体２３の内側面の各部に均一な膜厚で蒸着させることができる。
【００３７】
【実施例】
＜実施例１＞
図１及び図２に示した電気化学蒸着装置を用いてＹＳＺ固体電解質の成膜を行った。そのために、空気極支持管をなす基体２３のＬＳＭ管（外径２１ｍｍφ、内径１７ｍｍφ、長さ５０ｃｍ）を反応室２１において回転ねじ体５５の下部に取り付け、また外径１２ｍｍφ、内径９ｍｍφのカーボン製の原料蒸気供給管２６を反応室２１の中心部に取り付けた。そして、反応室２１を１Ｔｏｒｒ程度まで真空にし、ヒータ２２によって１２００℃に加熱し、さらに反応室２１の基体２３の外側にアルゴン／水蒸気／酸素の酸化ガス２４を０．５リットル／ｍｉｎ の流量で供給した。
【００３８】
そしてマスフローコントローラ３３，３４によって塩化イットリウム、塩化ジルコニウムそれぞれの微粉末を１：５の重量比で、かつ原料粉末重量に換算して両方で５ｇ／ｈｒ程度となる流量で気化室（図示せず）に供給して１２００℃に加熱して気化させて原料蒸気とし、これをさらに原料蒸気供給管２６から反応室２１の基体２３の内側に供給し、５時間の電気化学蒸着を行い、約５０μｍのＹＳＺ固体電解質膜２８を成膜した。この電気化学蒸着の間、モータ５３によって原料蒸気供給管２６を０．０１ｒｐｍでゆっりくと正逆回転させることによって最下位置から最上位置まで上下移動させた。
【００３９】
得られた固体電解質膜は緻密で均一な膜厚であった。
【００４０】
＜実施例２＞
図３に示した電気化学蒸着装置を用い、塩化イットリウム、塩化ジルコニウムそれぞれの微粉末をエタノールと重量比で１：１に混合した原料液を１：５の割合で、かつ原料粉末重量に換算して両方で５ｇ／ｈｒ程度となる流量で装置に供給し、１２００℃に加熱して希釈剤を蒸発分解し、また原料粉末を気化させて原料蒸気にし、これを実施例１と同じく１Ｔｏｒｒ程度の真空で、１２００℃に加熱した反応室２１の基体２３の内側に原料蒸気供給管２６を通じて供給しつつ、電気化学蒸着を行った。基体２３の回転速度の設定は実施例１と同じにした。
【００４１】
得られたＹＳＺ固体電解質膜２８は約５０μｍであり、緻密で均一な膜厚であった。
【００４２】
【発明の効果】
以上のように請求項１の発明の電気化学蒸着装置によれば、蒸着原料粉末を気化させて反応室に導入して蒸着基体の内周面に電気化学蒸着させる際に、蒸着基体を軸周りに回転させ、かつ軸方向に移動させることによって、反応室内の蒸着原料蒸気の流れや酸化ガスの流れが不均一であっても蒸着基体の表面各所に均一な膜厚で蒸着原料蒸気を蒸着させ、膜厚の均一な固体電解質を成膜することができる。
【００４３】
請求項２の発明の固体電解質の成膜方法によれば、請求項１の発明の電気化学蒸着装置を用いて蒸着基体の内周面に固体電解質膜を成膜するので、蒸着基体の内周面全体に渡り、均一な膜厚の固体電解質膜を成膜することができる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態の電気化学蒸着装置の断面図。
【図２】上記の実施の形態の電気化学蒸着装置の基体回転・移動機構部分の拡大断面図。
【図３】本発明の第２の実施の形態の電気化学蒸着装置の断面図。
【図４】従来の円筒固体電解質型燃料電池の斜視図。
【図５】他の従来の円筒固体電解質型燃料電池の断面図。
【図６】従来の電気化学蒸着装置の断面図。
【図７】一般的な電気化学蒸着作用の説明図。
【符号の説明】
２１ 反応室
２２ ヒータ
２３ 基体
２４ 酸化ガス
２５ 原料蒸気
２６ 原料蒸気供給管
２８ ＹＳＺ膜
３１ パウダーフィーダ
３２ パウダーフィーダ
３３ マスフローコントローラ
３４ マスフローコントローラ
５１ スライドベース
５２ スライダ
５３ モータ
５４ 回転出力軸
５５ 回転ねじ体
６１ 雌ねじ部
６３ スライドガイド
６４ 支持筒体
７３ 排気口
７４ 排気口
８１ 原料液貯留部
８２ 原料液貯留部
８３ マスフローコントローラ
８４ マスフローコントローラ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrochemical vapor deposition apparatus and a solid electrolyte film forming method using the same.
[0002]
[Prior art]
Conventionally, a solid oxide fuel cell has a flat plate method and a cylindrical method, and the cylindrical method has a vertical stripe method and a horizontal stripe method. In particular, a cylindrical vertical stripe type solid oxide fuel cell has the structure shown in FIG. This conventional cylindrical vertical stripe type solid electrolyte fuel cell 106 includes an air electrode support tube 101 of porous lanthanum manganite oxide (LaMnOx), a solid electrolyte 102 made of yttria-stabilized zirconia (YSZ), nickel, A cermet fuel electrode 103 made of cobalt, nickel alloy or cobalt alloy and YSZ is laminated, and the interconnector 104 is insulated from the fuel electrode 103 at a part of the outer peripheral surface and connected to the internal air electrode support tube 101. Are arranged in the form of
[0003]
However, in such a conventional vertical-stripe cylindrical solid oxide fuel cell, the materials of each element are all made of ceramics and operate at a high temperature of about 850 to 1050 ° C. There is a problem in that stress is concentrated near the overlapping interconnector 104 and the bottom of the battery and cracks are likely to occur.
[0004]
In order to solve this conventional problem, Japanese Patent Application Laid-Open No. 7-263001 proposes a solid oxide fuel cell 110 having a structure shown in FIG. This proposed conventional solid oxide fuel cell 110 is characterized by a structure in which a conductive tube 111 for fuel supply is inserted in the center. That is, a fuel electrode 112, a solid electrolyte 113, and an air electrode 114 are formed in this order from the inside, and a fuel supply conductive tube 111 having a number of holes for fuel injection is inserted in the center, and this conductive tube 111 is inserted. A conductive felt 115 having a fuel reforming function is filled between the fuel electrode 112 and the fuel electrode 112, a fuel gas 116 is supplied to the conductive tube 111, and air 117 is circulated on the outer periphery.
[0005]
The power generation operation of the solid oxide fuel cell 110 will be described. A fuel gas 116 such as natural gas, methane, or coal gasification gas is supplied into the conductive tube 111 of the battery 110, and the porous tube of the conductive tube 111 is supplied. The conductive felt 115 is ejected through the wall, and the conductive felt 115, the fuel electrode 112, and the solid electrolyte 113 are subjected to the following chemical formula 1 under high temperature conditions, usually 650 ° C. to 1050 ° C. Initiate a reforming reaction.
[0006]
[Chemical 1]

For the hydrogen generated by this reforming reaction, a power generation reaction of the following chemical formula 2 is caused at the portion of the fuel electrode 112 and the air electrode 114 opposite to each other through the solid electrolyte 113, and the released electrons are collected. To get the generated power.
[0007]
[Chemical formula 2]

That is, at the fuel electrode 112, as shown in the chemical formula 2 (a), hydrogen generated by the reforming reaction reacts with oxide ions supplied from the solid electrolyte 113 to generate water vapor and electrons. Then, when the electrons generated at the fuel electrode 112 pass through the conductive felt 115 and the conductive tube 111 to the external circuit from the cathode 118 and reach the air electrode 114 through the anode 119, the air electrode 114 has chemical formula 2 (b As shown in the formula, it reacts with oxygen in the air 117 to generate oxide ions, which are released to the solid electrolyte 113, reach the fuel electrode 112 side, and are subjected to the reaction of formula 2 (a). It is.
[0008]
In the fuel cell 110 of such a power generation mechanism, the air electrode 114, the solid electrolyte 113, and the fuel electrode 112 are formed as follows. First, a thin and dense YSZ film is formed on a lanthanum manganite-based porous substrate to be the air electrode 114 by using an electrochemical deposition method, that is, a CVD (Chemical Vapor Deposition) -EVD (Electrochemical Vapor Deposition) method. Is formed as a solid electrolyte 113, and the YSZ film is further coated with nickel, cobalt, nickel or an alloy containing nickel as a main component, or nickel zirconia cermet powder, and similarly subjected to electrochemical vapor deposition to be porous. The fuel electrode 112 is formed into a film, or is formed by using a spraying method as disclosed in Japanese Patent Laid-Open No. 4-349343.
[0009]
As an electrochemical vapor deposition apparatus for forming a film of the solid electrolyte 113, an apparatus having a structure shown in FIG. 6 is used. In this conventional electrochemical vapor deposition apparatus, the inside of the reaction chamber 21 is in a state close to a vacuum, about 1 Torr, and the heater 22 adds porous strontium serving as an air electrode support tube under a temperature condition of about 1000 to 1200 ° C. A mixed oxidation gas 24 of argon Ar, oxygen O ₂ , and water vapor H ₂ O is introduced to the outside of the lanthanum manganite (LSM) substrate 23, and yttrium and zirconium chlorides that are raw materials for the YSZ film on the other side. A vapor 25 of YCl ₃ and ZrCl ₄ is mixed with argon (Ar) gas as a carrier gas and supplied from a raw material vapor supply pipe 26.
[0010]
The raw material vapor 25 supply system stores fine powders of yttrium chloride YCl ₃ and zirconium chloride ZrCl ₄ in powder feeders (MPF) 31 and 32, and mass flow controllers (MFC) 33 and 34 at a predetermined flow rate. By supplying the argon carrier gas 35, the raw material fine powder is mixed into the carrier gas 35 and supplied to the raw material vapor supply pipe 26 of the reaction chamber 21 through the pipe 36, and the heater 22 is heated in the raw material vapor supply pipe 26 to heat the gas. The raw material vapor 25 is supplied into the reaction chamber 21.
[0011]
By using the electrochemical vapor deposition apparatus having such a structure, as shown in FIG. 7A, the oxidizing gas 24 and the raw material vapor 25 that initially pass through the numerous holes 27 of the base 23 are converted into the chemical formula 3 As shown in FIG. 7B, the YSZ film 28 is generated on the surface of the base 23 and the many holes 27 of the base 23 are gradually closed. This is the CVD stage.
[0012]
[Chemical 3]

When this CVD step is completed, the raw material vapor 25 and the oxidizing gas 24 do not react directly, and oxygen from the oxidizing gas 24 is reduced on the YSZ surface, and the inside of the YSZ film 28 is converted into oxide ions O ^2−. Then, the process proceeds to the EVD stage where the reaction shown in the chemical formula 4 is performed with the raw material chloride vapor, and the YSZ film 28 is grown as shown in FIG.
[0013]
[Formula 4]

Thus, after the YSZ film 28 is formed as the solid electrolyte 113 by the electrochemical vapor deposition method, a fuel cell is manufactured by a method in which the fuel electrode 112 is further slurry-coated and then electrochemical vapor deposition or other methods.
[0014]
[Problems to be solved by the invention]
However, such a conventional electrochemical vapor deposition apparatus has the following problems. That is, as shown in FIG. 6, the raw material vapor 25 is discharged into the base 23 from the lower end opening of the raw material vapor supply pipe 26, the oxidizing gas is supplied to the outside of the base 23, and the chloride exhaust generated by the EVD-CVD reaction. 41 and the oxide exhaust 42 are structured to be discharged to the outside through the discharge ports 43 and 44 provided one by one in the upper part of the reaction furnace 21, respectively, so that a speed difference occurs in the gas flow in each part in the reaction furnace 21. There is a problem that this makes the film thickness of the solid electrolyte 28 deposited on the surface of the substrate 23 non-uniform.
[0015]
The present invention has been made in view of such conventional problems, and the thickness of the solid electrolyte can be made uniform by rotating the substrate and moving it in the axial direction during the electrochemical deposition. An object of the present invention is to provide an electrochemical deposition apparatus and a method for forming a solid electrolyte using the same.
[0016]
[Means for Solving the Problems]
According to the first aspect of the present invention, a tubular vapor deposition substrate is housed inside, vaporized vapor deposition raw material vapor is introduced into the vapor deposition substrate through a vapor introduction tube, and an oxidizing gas is introduced outside the vapor deposition substrate. Then, in an electrochemical vapor deposition apparatus comprising a reaction chamber for forming an electrochemical vapor deposition film on the inner peripheral surface of the vapor deposition substrate, rotating means for rotating the vapor deposition substrate around an axis, and the vapor deposition substrate in the axial direction And a moving means for moving.
[0017]
In the electrochemical vapor deposition apparatus of the invention of claim 1, when vapor deposition raw material powder is vaporized at a high temperature, introduced into the reaction chamber and electrochemical vapor deposited on the inner peripheral surface of the vapor deposition substrate, the vapor deposition substrate is rotated about its axis, In addition, by moving in the axial direction, even if the flow of the vapor deposition raw material vapor and the flow of the oxidizing gas in the reaction chamber are non-uniform, the vapor of the raw material is deposited in a uniform film thickness on the surface of the vapor deposition substrate. A solid electrolyte is formed into a film.
[0018]
The invention of claim 2 is a solid electrolyte film forming method using the electrochemical vapor deposition apparatus according to claim 1, wherein each of the yttrium chloride powder and the zirconium chloride powder is derived at a predetermined ratio and a predetermined flow rate. Vaporizing in a high temperature atmosphere to generate a vapor deposition raw material vapor, introducing the vapor deposition raw material vapor into the vapor introducing pipe of the reaction chamber, rotating the vapor deposition substrate around the axis, and moving it in the axial direction An electrochemical deposition film is formed on the peripheral surface.
[0019]
In the solid electrolyte film forming method according to the second aspect of the present invention, since the solid electrolyte film is formed on the inner peripheral surface of the vapor deposition substrate using the electrochemical vapor deposition apparatus according to the first aspect, the entire inner peripheral surface of the vapor deposition substrate is formed. A solid electrolyte membrane with a uniform film thickness can be formed.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 show an electrochemical vapor deposition apparatus according to one embodiment of the present invention. The electrochemical vapor deposition apparatus according to the first embodiment is similar to the conventional example shown in FIG. 6, and the reaction chamber 21 is in a state close to a vacuum, about 1 Torr, and a temperature of about 1000 to 1200 ° C. by the heater 22. Under the conditions, a mixed oxidizing gas 24 of argon Ar, oxygen O ₂ and water vapor H ₂ O is introduced to the outside of the porous LSM base 23 serving as the air electrode support tube, and yttrium serving as a raw material for the YSZ film is introduced inside. In this configuration, a vapor 25 of zirconium chlorides YCl ₃ and ZrCl ₄ is mixed with an argon (Ar) gas as a carrier gas and supplied from a raw material vapor supply pipe 26. In addition, the raw material vapor 25 is supplied by storing fine powders of yttrium chloride YCl ₃ and zirconium chloride ZrCl ₄ in powder feeders (MPF) 31 and 32, and mass flow controllers (MFC) 33 and 34 at a predetermined flow rate. By supplying the argon carrier gas 35, the raw material fine powder is mixed into the carrier gas 35 and supplied to the raw material vapor supply pipe 26 of the reaction chamber 21 through the pipe 36, and the heater 22 is heated in the raw material vapor supply pipe 26 to heat the gas. The raw material vapor 25 is supplied into the reaction chamber 21.
[0021]
A motor 53 is slidably supported in the vertical direction by a slider 52 engaged with a slide base 51 fixed to an external fixing member (not shown). The body 55 is fixed to rotate horizontally around the vertical axis. An upper end portion of the LSM base 23 is fixed to the lower surface side of the rotating screw body 55 by a fastening ring 56. It is assumed that vent holes 23a for discharging chloride exhaust described later are formed at a plurality of locations in the upper portion of the LSM substrate 23 (the portion where the solid electrolyte membrane is not formed).
[0022]
On the other hand, a support cylinder 64 in which a female thread 61 is formed in the upper part and a slide guide 63 in which an O-ring 62 that follows the lower part is fitted is fixed to the upper end of the reaction chamber 21. The support cylinder 64 is formed with chloride exhaust vents 65 at a plurality of positions. The aforementioned rotating screw body 55 is screwed into the female thread portion 61 of the support cylinder 64.
[0023]
A partition plate 71 is airtightly attached to the inside of the reaction chamber 21 at a position below the support cylinder 64. An O-ring 72 is fitted into the inner peripheral portion of the partition plate 71 and is brought into airtight and slidable contact with the outer peripheral surface of the LSM base 23. An exhaust port 73 for exhausting chloride is formed in the reaction chamber 21 at a position above the partition plate 71, and an exhaust port 74 for exhausting oxide is formed in the reaction chamber 21 at a position below the partition plate 71. Has been.
[0024]
The raw material vapor supply pipe 26 is piped through the central portions of the motor 53, the rotary output shaft 54, the rotary screw body 55, and the tightening ring 56, and is hermetically sealed by a sealing means (not shown). The motor 53, the rotation output shaft 54, the rotating screw body 55 and the tightening ring 56 can be rotated and slid in an airtight manner with respect to the raw material vapor supply pipe 26.
[0025]
Next, a procedure for forming a solid electrolyte film by the electrochemical vapor deposition apparatus having the above configuration will be described. By storing raw material fine powders of yttrium chloride YCl ₃ and zirconia chloride ZrCl ₄ in powder feeders (MPF) 31 and 32 and supplying an argon carrier gas 35 at a predetermined flow rate by mass flow controllers (MFC) 33 and 34 A raw material (for example, mixed in a weight ratio of ZrCl ₄ : YCl ₃ = 5: 1) mixed with the raw material fine powder in the carrier gas 35 is supplied to the raw material vapor supply pipe 26 through the pipe 36 at a speed of about 4 to 10 g / hr. The raw material is vaporized by the heating of the heater 22 and supplied as raw material vapor to the inside of the LSM substrate 23 in the reaction chamber 21 from below.
[0026]
The inside of the reaction chamber 21 is in a state close to a vacuum, about 1 Torr, and a temperature condition of about 1000 to 1200 ° C. by the heater 22, and the outside of the porous LSM substrate 23 serving as an air electrode support tube is argon Ar, oxygen O ₂ , a mixed oxidizing gas 24 of water vapor H ₂ O is introduced at a flow rate of 0.4 to 2.0 liters / min. Inside, vapors of yttrium and zirconium chlorides YCl ₃ and ZCl _{4 which} are raw materials for the YSZ film 25 is mixed with argon Ar as a carrier gas and supplied from the lower end of the raw material vapor supply pipe 26. As a result, the YSZ film 28 is formed as a solid electrolyte film on the inner surface of the substrate 23 by the CVD-EVD action shown in FIG.
[0027]
During the supply of the raw material vapor 25, the motor 53 is rotated in the forward and reverse directions, and the rotating screw body 55 is slowly rotated in the forward and reverse directions via the rotation output shaft 54, whereby the internal thread of the support cylinder 64 in the upper part of the reaction chamber 21 is obtained. The rotary screw body 55 is rotated up and down together with the motor 53 by being screwed with the part 1, and the base member 23 attached thereto is also moved up and down while rotating. The rotation speed of the substrate 23 is a fine speed of 0.005 to 0.05 rpm. As a result, the YSZ film 28 is deposited with a uniform film thickness on each part of the inner surface of the substrate 23 even when there are variations in the speed, concentration, temperature conditions in the reaction chamber 21, and offset of the central axis. .
[0028]
The chloride exhaust 41 produced by the CVD-EVD method gathers in a room above the partition plate 71 in the reaction chamber 21 through the vent 23 a on the base 23 and the vent 65 of the support cylinder 64, and from here the exhaust 73 It is discharged to the outside through. The oxide exhaust 42 gathers below the partition plate 72 in the reaction chamber 21, and is exhausted to the outside through the exhaust port 74.
[0029]
In this way, in the solid electrolyte film forming method using the electrochemical vapor deposition apparatus of the first embodiment, the substrate 23 is reacted when the solid electrolyte YSZ film 28 is formed on the substrate 23 by the CVD-EVD method. Since it is moved up and down while rotating in the chamber 21, the YSZ film 28 is formed on the substrate 23 even if there are variations in the speed, concentration, temperature conditions, etc. of the raw material vapor 25 in the upper and lower directions in the reaction chamber 21 and in the circumferential direction. It can deposit with a uniform film thickness on each part of the inner surface.
[0030]
Next, the electrochemical vapor deposition apparatus of the 2nd Embodiment of this invention is demonstrated based on FIG. The electrochemical vapor deposition apparatus according to the second embodiment includes raw material liquid storage units 81 and 82, and each of the raw material fine powders yttrium chloride YCl ₃ and zirconium chloride ZrCl ₄ is diluted with ethanol as a diluent to be a mixed liquid. And temporarily store here. The raw material liquids stored in the raw material liquid storage units 81 and 82 are controlled to be discharged at a constant time by mass flow controllers (MFCs) 83 and 84, respectively.
[0031]
The structure of the reaction chamber 21 and the structure of the rotation and slide mechanism with respect to the base 23 in the reaction chamber 21 are the same as those of the first embodiment shown in FIGS.
[0032]
Next, a solid electrolyte film forming procedure using the electrochemical vapor deposition apparatus of the second embodiment will be described. Each fine powder of yttrium chloride and zirconium chloride is mixed with an appropriate amount of ethanol to prepare a raw material mixture, and these are stored in the raw material liquid storage portions 81 and 82, respectively.
[0033]
The reaction chamber 21 is depressurized to a pressure close to vacuum, about 1 Torr, and further heated to a temperature of 1000 to 1200 ° C. by the heater 22. Then, a mixed oxidizing gas 24 of argon, water vapor and oxygen is supplied to the outside of the substrate 23 in the reaction chamber 21 at a flow rate of 0.4 to 2.0 liter / min.
[0034]
After such a preliminary process, argon gas is supplied at a predetermined flow rate by the mass flow controllers 83 and 84 to the raw material liquid stored in the raw material storage portions 81 and 82, and these raw material liquids are supplied to, for example, both raw material liquids. Is supplied at a flow rate of about 4 to 10 g / hr in total in terms of the weight of the raw material powder contained therein, and is heated in a vaporization chamber (not shown) to evaporate and decompose the diluent. After yttrium chloride and zirconium chloride are vaporized, the raw material vapor supply pipe 26 is supplied together with the argon gas Ar serving as a carrier gas, and the raw material vapor 25 is supplied from the raw material vapor supply pipe 26 to the inside of the LSM substrate 23 in the reaction chamber 21. Supply from the bottom.
[0035]
During the supply of the raw material vapor 25, the motor 53 is rotated, and the rotating screw body 55 is slowly rotated via the rotation output shaft 54, so that the base 23 is moved up and down together with the rotating screw body 55.
[0036]
By continuing this procedure for a predetermined time, for example, 5 hours, the YSZ film 28 can be formed as a solid electrolyte film on the inner surface of the substrate 23 by the CVD-EVD action as in the first embodiment. Moreover, even if there are variations in the speed and concentration of the raw material vapor 25 and the temperature conditions in the reaction chamber 21, the base 23 moves up and down while rotating, so the YSZ film 28 is a uniform film on each part of the inner surface of the base 23. It can be deposited in thickness.
[0037]
【Example】
<Example 1>
A YSZ solid electrolyte was formed using the electrochemical vapor deposition apparatus shown in FIGS. For this purpose, the LSM tube (outer diameter 21 mmφ, inner diameter 17 mmφ, length 50 cm) of the base 23 forming the air electrode support tube is attached to the lower part of the rotating screw body 55 in the reaction chamber 21, and is made of carbon having an outer diameter of 12 mmφ and an inner diameter of 9 mmφ. The raw material vapor supply pipe 26 was attached to the center of the reaction chamber 21. Then, the reaction chamber 21 is evacuated to about 1 Torr, heated to 1200 ° C. by the heater 22, and an argon / water vapor / oxygen oxidizing gas 24 is flown outside the base 23 of the reaction chamber 21 at a flow rate of 0.5 liter / min. Supplied.
[0038]
The mass flow controllers 33 and 34 vaporize the yttrium chloride and zirconium chloride fine powders at a weight ratio of 1: 5 and at a flow rate of about 5 g / hr in terms of both raw material powder weights (not shown). Is heated to 1200 ° C. and vaporized to form raw material vapor, which is further supplied from the raw material vapor supply pipe 26 to the inside of the substrate 23 of the reaction chamber 21 and subjected to electrochemical vapor deposition for 5 hours. A YSZ solid electrolyte membrane 28 was formed. During this electrochemical vapor deposition, the raw material vapor supply pipe 26 was moved up and down from the lowest position to the highest position by slowly rotating the raw material vapor supply pipe 26 at 0.01 rpm.
[0039]
The obtained solid electrolyte membrane was dense and uniform.
[0040]
<Example 2>
Using the electrochemical vapor deposition apparatus shown in FIG. 3, a raw material liquid in which fine powders of yttrium chloride and zirconium chloride were mixed with ethanol in a weight ratio of 1: 1 was converted to the weight of the raw material powder at a ratio of 1: 5. Then, both are supplied to the apparatus at a flow rate of about 5 g / hr, heated to 1200 ° C. to evaporate and decompose the diluent, and the raw material powder is vaporized into raw material vapor, which is about 1 Torr as in Example 1. While being supplied through the raw material vapor supply pipe 26 to the inside of the base 23 of the reaction chamber 21 heated to 1200 ° C. in vacuum, electrochemical deposition was performed. The setting of the rotation speed of the substrate 23 was the same as that in Example 1.
[0041]
The obtained YSZ solid electrolyte membrane 28 was about 50 μm, and had a dense and uniform thickness.
[0042]
【The invention's effect】
As described above, according to the electrochemical vapor deposition apparatus of the first aspect of the present invention, when the vapor deposition raw material powder is vaporized and introduced into the reaction chamber for electrochemical vapor deposition on the inner peripheral surface of the vapor deposition base, the vapor deposition base is rotated around the axis. By rotating and rotating in the axial direction, vapor deposition raw material vapor is deposited with a uniform film thickness on the surface of the vapor deposition substrate even if the flow of vapor deposition raw material vapor and the flow of oxidizing gas in the reaction chamber are not uniform. A solid electrolyte having a uniform film thickness can be formed.
[0043]
According to the solid electrolyte film forming method of the second aspect of the invention, the solid electrolyte film is formed on the inner peripheral surface of the vapor deposition substrate using the electrochemical vapor deposition apparatus of the first aspect of the invention. A solid electrolyte membrane having a uniform film thickness can be formed over the entire surface.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electrochemical vapor deposition apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of a substrate rotation / movement mechanism portion of the electrochemical vapor deposition apparatus according to the above embodiment.
FIG. 3 is a cross-sectional view of an electrochemical vapor deposition apparatus according to a second embodiment of the present invention.
FIG. 4 is a perspective view of a conventional cylindrical solid oxide fuel cell.
FIG. 5 is a cross-sectional view of another conventional cylindrical solid oxide fuel cell.
FIG. 6 is a cross-sectional view of a conventional electrochemical vapor deposition apparatus.
FIG. 7 is an explanatory view of a general electrochemical vapor deposition action.
[Explanation of symbols]
21 Reaction chamber 22 Heater 23 Substrate 24 Oxidizing gas 25 Raw material vapor 26 Raw material vapor supply pipe 28 YSZ film 31 Powder feeder 32 Powder feeder 33 Mass flow controller 34 Mass flow controller 51 Slide base 52 Slider 53 Motor 54 Rotation output shaft 55 Rotating screw body 61 Female screw Unit 63 slide guide 64 support cylinder 73 exhaust port 74 exhaust port 81 raw material liquid storage unit 82 raw material liquid storage unit 83 mass flow controller 84 mass flow controller

Claims (2)

A cylindrical vapor deposition substrate is housed inside, vaporized vapor deposition raw material vapor is introduced into the vapor deposition substrate through a vapor introduction tube, and an oxidizing gas is introduced outside the vapor deposition substrate, so that the vapor deposition substrate In an electrochemical vapor deposition apparatus comprising a reaction chamber for forming an electrochemical vapor deposition film on the inner peripheral surface,
An electrochemical deposition apparatus comprising: a rotating unit that rotates the deposition substrate about an axis; and a moving unit that moves the deposition substrate in the axial direction. Deriving each of yttrium chloride powder and zirconium chloride powder at a predetermined ratio and a predetermined flow rate, and vaporizing in a high temperature atmosphere to generate a vapor deposition raw material vapor,
The vapor deposition raw material vapor is introduced into the vapor introduction pipe of the reaction chamber, the vapor deposition substrate is rotated around an axis, and an electrochemical vapor deposition film is formed on the inner peripheral surface while moving in the axial direction. A solid electrolyte film forming method using the electrochemical vapor deposition apparatus according to claim 1.

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