JP5268717B2

JP5268717B2 - Brazing material and bonded body for air bonding

Info

Publication number: JP5268717B2
Application number: JP2009056805A
Authority: JP
Inventors: 雄一郎山内; 敦菊地
Original assignee: NHK Spring Co Ltd
Current assignee: NHK Spring Co Ltd
Priority date: 2009-03-10
Filing date: 2009-03-10
Publication date: 2013-08-21
Anticipated expiration: 2029-03-10
Also published as: JP2010207863A

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brazing filler metal for atmospheric joining which can easily join metals to each other, ceramics to each other, and a metal and ceramics in the air without using flux, regarding a brazing filler metal for atmospheric joining and a joined body being a sealing material for a solid oxide type fuel cell, particularly, the brazing filler metal for atmospheric joining for maintaining air-tightness of a fuel gas and an oxidizer gas between the components of a solid oxide type fuel cell operating at 600 to 800°C and a joined body with a sealing structure including the brazing filler metal for joining. <P>SOLUTION: The brazing filler metal for atmospheric joining is composed of Ag as the main component; Ge, Cr or their oxides, and inevitable impurities as the balance, and is made into a composite oxide mainly composed of Ge and Cr in the joining stage in the atmosphere. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は、固体酸化物型燃料電池のシール材料である大気接合用ろう材及び接合体に関する。本発明は、特に６００〜８００℃で動作する固体酸化物型燃料電池の構成部品間の燃料ガス及び酸化剤ガスの気密性を保つための大気接合用ろう材、及び該接合用ろう材を含むシール構造を備えた接合体に関する。 The present invention relates to a brazing material for air bonding, which is a sealing material for a solid oxide fuel cell, and a bonded body. The present invention includes a brazing material for air bonding for maintaining airtightness of fuel gas and oxidant gas between components of a solid oxide fuel cell operating particularly at 600 to 800 ° C., and the bonding brazing material. The present invention relates to a joined body having a seal structure.

従来、燃料電池のガスシール法として、ペースト状のガラスを用いたガラスシール法、及びろう付法が用いられている。
ろう付法には、真空ろう付及びフラックスを用いた大気ろう付の大きく２つの施工環境がある。これらは、いずれもろう付加熱時の接合部材とろう材の酸化防止のために必要とされるものである。 Conventionally, as a gas sealing method for a fuel cell, a glass sealing method using a paste-like glass and a brazing method are used.
There are roughly two construction environments for brazing methods: vacuum brazing and atmospheric brazing using flux. These are all required for preventing oxidation of the joining member and the brazing material during the brazing heat.

真空ろう付は、真空中で加熱することで、ワークとろう材の酸化を防止することで良好な接合継手が得られる。一方、フラックスを用いた大気ろう付は、フラックスにより接合部で還元雰囲気を作ることにより良好な接合界面が得られる。 In vacuum brazing, a good joint can be obtained by heating in vacuum to prevent oxidation of the workpiece and the brazing material. On the other hand, in air brazing using a flux, a good joining interface can be obtained by creating a reducing atmosphere at the joint with the flux.

また、セラミックスと金属をろう付する手法として、活性金属ろう付法が挙げられる。この手法で良好な接合体を得るためには、真空中、及び窒素雰囲気などの非酸化雰囲気での熱処理が必要である。 An active metal brazing method may be used as a method for brazing ceramics and metal. In order to obtain a good bonded body by this method, heat treatment is required in a vacuum and in a non-oxidizing atmosphere such as a nitrogen atmosphere.

一方、大気中でろう付する手法として、反応性大気ろう付法（Reactive Air Brazing）がある（特許文献１）。これは、セラミックスと大気中でＡｌ酸化物層を形成する耐熱金属とを、ＡｇにＣｕＯを添加したろう材を用いて大気中で接合するものであり、ろう材の主成分がＡｇなどの貴金属成分であるため、フラックスを用いずにろう付できる特長を有する。
更に、前記反応性大気ろう付法に対し、Ａｇの添加元素としてＣｕやＣｕＯを用いずに高温水素耐久性を高めた大気ろう付法がある（特許文献２）。 On the other hand, as a technique for brazing in the air, there is a reactive air brazing method (Patent Document 1). In this method, ceramics and a heat-resistant metal that forms an Al oxide layer in the atmosphere are joined in air using a brazing material in which CuO is added to Ag. The main component of the brazing material is a noble metal such as Ag. Since it is a component, it has the feature that it can be brazed without using flux.
Furthermore, there is an air brazing method in which high temperature hydrogen durability is improved without using Cu or CuO as an additive element of Ag as compared with the reactive air brazing method (Patent Document 2).

ＵＳ２００３／０１３２２７０Ａ１US2003 / 0132270A1 特開２００７−３３１０２６号公報JP 2007-331026 A

ガラスシール法は、燃料電池のシール材としては、強度が十分ではなく、ガラス成分とセパレータの金属成分が反応して劣化の原因になるなど、様々な問題が残っている。
一方、セラミックスと金属を接合させる活性金属ろう付法では、Ｔｉなどの活性金属を用いるため、熱処理雰囲気が真空中に限られる。しかし、セルへの非酸化雰囲気での熱処理は、セルのカソード材料である金属酸化物セラミックスの特性を変化させてしまうため、適応することが困難である。 The glass sealing method is not sufficient as a sealing material for fuel cells, and various problems remain such that the glass component and the metal component of the separator react to cause deterioration.
On the other hand, in the active metal brazing method for joining ceramics and metal, an active metal such as Ti is used, so that the heat treatment atmosphere is limited to a vacuum. However, heat treatment in a non-oxidizing atmosphere on the cell is difficult to adapt because it changes the characteristics of the metal oxide ceramics that are the cathode material of the cell.

こうした課題を踏まえ、前記反応性大気ろう付法の報告がなされている。しかしながら、本出願人の研究では、シール面を介して一方は水素雰囲気、もう一方は酸素雰囲気であり、温度は６００〜８００℃という燃料電池の動作環境下では、水素及び酸素が各々ろう材主成分のＡｇ中に拡散しており、ろう材中で水素と酸素が反応し、ボイドが生じる。また、致命的な問題として、拡散してきた水素によりセラミックスとの反応層として形成していたＣｕＯの一部がＣｕに還元され、良好な接合界面を保持できない問題があることが判明した。更に、特許文献２では、接合率が良好とはいえず、十分なシール性能であるとはいえない。 Based on these problems, the reactive air brazing method has been reported. However, in the applicant's research, one of the hydrogen atmosphere and the other is an oxygen atmosphere through the sealing surface, and in the operating environment of the fuel cell at a temperature of 600 to 800 ° C., hydrogen and oxygen are mainly brazing filler metals. It diffuses in the component Ag, and hydrogen and oxygen react in the brazing material to generate voids. Further, as a fatal problem, it has been found that a part of CuO formed as a reaction layer with ceramics is reduced to Cu by the diffused hydrogen, and a good bonding interface cannot be maintained. Furthermore, in patent document 2, it cannot be said that a joining rate is favorable and it cannot be said that it is sufficient sealing performance.

本発明は上述した課題を解決するためなされたもので、大気中で、金属同士、セラミックス同士、及び金属とセラミックスを簡単にフラックス無しで接合できる大気接合用ろう材、及び高温水素／酸素雰囲気において優れた接合界面を保ち、さらには優れた接合率を保つことが可能な接合体を提供することを目的とする。 The present invention has been made to solve the above-described problems. In the atmosphere, a brazing material for air bonding that can easily bond metals, ceramics, and metals and ceramics without flux, and a high-temperature hydrogen / oxygen atmosphere. An object is to provide a bonded body capable of maintaining an excellent bonding interface and further maintaining an excellent bonding rate.

本発明の大気接合用ろう材は、Ａｇを９４〜９７ｗｔ％と、Ｇｅ又はＧｅ酸化物を１〜５ｗｔ％と、Ｃｒ又はＣｒ酸化物を１〜３ｗｔ％と、残部としての不可避不純物からなり、これらの合計が１００ｗｔ％となるように調整されていることを特徴とする。
Air bonding brazing material of the present invention, a 94 to 97 wt% of Ag, and 1 to 3 wt% and Ge, or 1-5 wt% of Ge oxide, a Cr or Cr oxide, consists inevitable impurities as the balance, The total is adjusted so that it may become 100 wt%.

本発明によれば、大気中で、金属同士、セラミックス同士、及び金属とセラミックスを簡単にフラックス無しで接合できる大気接合用ろう材が得られる。また、本発明によれば、高温水素／酸素雰囲気において優れた接合界面を保ち、さらには優れた接合率を保つことが可能な接合体が得られる。 ADVANTAGE OF THE INVENTION According to this invention, the brazing material for air joining which can join metals, ceramics, and a metal and ceramics easily without a flux in air | atmosphere is obtained. Further, according to the present invention, it is possible to obtain a bonded body capable of maintaining an excellent bonding interface in a high-temperature hydrogen / oxygen atmosphere and further maintaining an excellent bonding rate.

図１は、本発明の実施例１に係る接合体の外観図を示す。FIG. 1 is an external view of a joined body according to Example 1 of the present invention. 図２は、図１の接合体の一部を切欠した外観図を示す。FIG. 2 shows an external view in which a part of the joined body of FIG. 1 is cut away. 図３は、図１の接合体の断面二次電子像接合度断面図を示す。FIG. 3 shows a sectional view of the secondary electron image bonding degree of the bonded body of FIG. 図４は、図３の要部を拡大した断面二次電子像を示す。FIG. 4 shows an enlarged cross-sectional secondary electron image of the main part of FIG. 図５は、実施例２に係る接合体の接合後の透過Ｘ線画像、並びに要部の拡大断面二次電子像を示す。FIG. 5 shows a transmission X-ray image after joining of the joined body according to Example 2, and an enlarged cross-sectional secondary electron image of the main part. 図６は、比較例１に係る接合体の接合後の透過Ｘ線画像、並びに要部の拡大断面二次電子像を示す。FIG. 6 shows a transmission X-ray image after bonding of the bonded body according to Comparative Example 1, and an enlarged cross-sectional secondary electron image of the main part. 図７は、比較例２に係る接合体の接合後の透過Ｘ線画像、並びに要部の拡大断面二次電子像を示す。FIG. 7 shows a transmission X-ray image after bonding of the bonded body according to Comparative Example 2, and an enlarged cross-sectional secondary electron image of the main part. 図８は、高温水素耐久試験を行うための装置の概略図を示す。FIG. 8 shows a schematic view of an apparatus for performing a high-temperature hydrogen durability test. 図９は、実施例３に係る接合体の高温水素耐久試験前の断面二次電子像を示す。FIG. 9 shows a cross-sectional secondary electron image of the joined body according to Example 3 before the high-temperature hydrogen durability test. 図１０は、実施例３に係る接合体の高温水素耐久試験後の断面二次電子像を示す。FIG. 10 shows a cross-sectional secondary electron image after the high-temperature hydrogen durability test of the joined body according to Example 3. 図１１は、セルと金属板をろう材層で接合した接合体試料の試験後の断面二次電子像を示す。FIG. 11 shows a cross-sectional secondary electron image after a test of a joined body sample in which a cell and a metal plate are joined with a brazing material layer. 図１２は、図１１の試料の金属板領域，セル領域及びろう材層領域における各元素分析結果を示す。FIG. 12 shows each elemental analysis result in the metal plate region, cell region and brazing material layer region of the sample of FIG. 図１３は、比較例３に係る接合体の高温水素耐久試験前の断面二次電子像を示す。FIG. 13 shows a cross-sectional secondary electron image of the joined body according to Comparative Example 3 before the high-temperature hydrogen durability test. 図１４は、比較例３に係る接合体の高温水素耐久試験後の断面二次電子像を示す。FIG. 14 shows a cross-sectional secondary electron image after the high-temperature hydrogen durability test of the joined body according to Comparative Example 3. 図１５は、比較例４に係る接合体の高温水素耐久試験前の断面二次電子像を示す。FIG. 15 shows a cross-sectional secondary electron image of the bonded body according to Comparative Example 4 before the high-temperature hydrogen durability test. 図１６は、比較例４に係る接合体の高温水素耐久試験後の断面二次電子像を示す。FIG. 16 shows a cross-sectional secondary electron image after the high-temperature hydrogen durability test of the joined body according to Comparative Example 4. 図１７は、実施例５に係る試験片同士の引張試験の説明図を示す。FIG. 17 is an explanatory diagram of a tensile test between test pieces according to Example 5.

以下、本発明について更に詳しく説明する。
本発明において、セラミックスとしては、例えば、ジルコニア，安定化ジルコニア，アルミナ，マグネシア，ステアタイト，ムライト，チタニア，シリカ，サイアロン等の酸化物セラミックスが挙げられる。また、母材となる金属としては、例えば、ステンレス，耐熱性ステンレス，ＦｅＣｒＡｌ合金，ＦｅＣｒＳｉ合,Ｎｉ基耐熱合金等が挙げられる。 Hereinafter, the present invention will be described in more detail.
In the present invention, examples of the ceramic include oxide ceramics such as zirconia, stabilized zirconia, alumina, magnesia, steatite, mullite, titania, silica, and sialon. Examples of the metal that serves as a base material include stainless steel, heat resistant stainless steel, FeCrAl alloy, FeCrSi alloy, and Ni-base heat resistant alloy.

本発明において、ろう材の主成分であるＡｇに添加する元素としては、Ａｇ中に固溶するものが好ましい。具体的には、Ｇｅ，Ｓｉ，Ｃｒ，Ａｌ，Ａｕ，Ｐｄ、Ｓｂ，Ｂｉの少なくとも１つの金属が挙げられる。 In the present invention, the element added to Ag, which is the main component of the brazing material, is preferably an element that dissolves in Ag. Specifically, at least one metal of Ge, Si, Cr, Al, Au, Pd, Sb, and Bi can be used.

以下に実施例を示すが、本発明は特に本実施例に限定されるものではない。
（実施例１）
図１〜図４を参照する。ここで、図１は実施例１に係る接合体の概観図、図２は図１の接合体を一部切欠した外観図、図３は接合後の接合体の断面二次電子像、図４は図３の要部を拡大した断面二次電子像を示す。 Examples are shown below, but the present invention is not particularly limited to these Examples.
Example 1
Please refer to FIGS. Here, FIG. 1 is a schematic view of the joined body according to Example 1, FIG. 2 is an external view of the joined body of FIG. 1 partially cut away, FIG. 3 is a cross-sectional secondary electron image of the joined body after joining, FIG. FIG. 4 shows an enlarged cross-sectional secondary electron image of the main part of FIG.

図中の符番１は、外径φ１４ｍｍ，内径８ｍｍの金属（日立金属製の商品名：ＺＭＧ２３２Ｌ）の筒状体である。この筒状体１には、外径φ６，肉厚１ｍｍのＳＵＳ３１０Ｓ製のパイプ３がＢＮｉ_５で真空ろう付されている。符番２は、固体酸化物型燃料電池に用いられる，２０ｍｍ×２０ｍｍのセラミック製のセルを示す。なお、図中の符番４は、本発明主に評価を行った大気ろう付部を示す。ここで、大気ろう付け用のろう材には、Ａｇ−２ｗｔ％Ｇｅ−１ｗｔ％Ｃｒ混合粉末ろうを、有機溶剤，有機バインダーでペーストとしたものを用いた。 Reference numeral 1 in the drawing is a cylindrical body of metal (trade name: ZMG232L, manufactured by Hitachi Metals) having an outer diameter of 14 mm and an inner diameter of 8 mm. A pipe 3 made of SUS310S having an outer diameter of φ6 and a thickness of 1 mm is vacuum brazed to the cylindrical body 1 with BNi ₅ . Reference numeral 2 indicates a 20 mm × 20 mm ceramic cell used for a solid oxide fuel cell. In addition, the number 4 in a figure shows the air brazing part which mainly evaluated this invention. Here, as the brazing material for air brazing, a paste prepared by mixing Ag-2 wt% Ge-1 wt% Cr mixed powder brazing with an organic solvent and an organic binder was used.

図１の接合体は、次のようにして作製する。まず、上記筒状体１に上記パイプ３をＢＮｉ５で真空ろう付する。次に、固体酸化物型燃料電池に用いられるセル２を２０ｍｍ×２０ｍｍに切断し、そのセル２の上に上記筒状体１を大気中９７０℃で３０分間保持して接合する。ここで、筒状体１の接合には上記ろう材を用いた。 The joined body of FIG. 1 is produced as follows. First, the pipe 3 is vacuum brazed to the cylindrical body 1 with BNi5. Next, the cell 2 used for the solid oxide fuel cell is cut into 20 mm × 20 mm, and the cylindrical body 1 is held on the cell 2 at 970 ° C. for 30 minutes in the atmosphere and joined. Here, the brazing material was used for joining the cylindrical body 1.

（実施例２）
実施例２では、実施例１と同様の板状のセルに、３０ｍｍ角，厚み０．１ｍｍの金属板（日立金属製の商品名：ＺＭＧ２３２Ｌ）を、実施例１と同様のろう材、接合条件で大気ろう付を行った。
図５（Ａ）は実施例２に係る接合体の接合後の透過Ｘ線画像を示し、図５（Ｂ）は図５（Ａ）のＸ−Ｘ’線に沿う拡大断面二次電子像を示す。なお、図１〜図４と同部材は同符番を付して説明を省略する。
図５（Ａ），（Ｂ）において、符番５は金属板、符番６は空洞部、符番７ははみ出したろう材を示す。 (Example 2)
In Example 2, a 30 mm square, 0.1 mm thick metal plate (trade name: ZMG232L manufactured by Hitachi Metals) is used in the same plate-like cell as in Example 1, and the same brazing material and bonding conditions as in Example 1 Atmospheric brazing was performed.
5A shows a transmission X-ray image after joining of the joined body according to Example 2, and FIG. 5B shows an enlarged cross-sectional secondary electron image along the line XX ′ in FIG. 5A. Show. In addition, the same member as FIGS. 1-4 is attached | subjected the same number, and description is abbreviate | omitted.
5A and 5B, reference numeral 5 denotes a metal plate, reference numeral 6 denotes a hollow portion, and reference numeral 7 denotes a protruding brazing material.

（比較例１）
実施例２と同じ材料、同じ接合条件で、Ａｇ−２ｗｔ％Ｃｕろうを用いて大気ろう付を行った。これは、特許文献１で用いられる大気ろう付法を適用したものである。
図６（Ａ）は比較例１に係る接合体の接合後の透過Ｘ線画像を示し、図６（Ｂ）は図６（Ａ）のＸ−Ｘ線に沿う拡大断面二次電子像を示す。なお、図１〜図５と同部材は同符番を付して説明を省略する。図６（Ａ），（Ｂ）より、比較例１の接合体の場合、実施例２よりもやや接合率が劣っていることがわかる。 (Comparative Example 1)
Atmospheric brazing was performed using Ag-2 wt% Cu brazing under the same material and the same joining conditions as in Example 2. This is an application of the atmospheric brazing method used in Patent Document 1.
6A shows a transmission X-ray image after joining of the joined body according to Comparative Example 1, and FIG. 6B shows an enlarged cross-sectional secondary electron image along the line XX of FIG. 6A. . The same members as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted. 6 (A) and 6 (B), it can be seen that in the case of the joined body of Comparative Example 1, the joining rate is slightly inferior to that of Example 2.

（比較例２）
実施例２と同じ材料、同じ接合条件で、Ａｇ−１ｗｔ％ＴｉＡｌ−０．６ｗｔ％Ｃｒろうを用いて大気ろう付を行った。これは、特許文献２で用いられる大気ろう付を適用したものである。図７（Ａ）は比較例２に係る接合体の接合後の透過Ｘ線画像を示し、図７（Ｂ）は図７（Ａ）のＸ−Ｘ線に同拡大断面二次電子像を示す。なお、図１〜図５と同部材は同符番を付して説明を省略する。
図７（Ａ），（Ｂ）より、比較例２の接合体の場合、実施例２や比較例１と比較して、さらにボイドが多く、接合率が著しく劣ることがわかる。また、図７（Ａ）において、金属板の表面が全体的に白くなっていることが確認できた。 (Comparative Example 2)
Atmospheric brazing was performed using Ag-1 wt% TiAl-0.6 wt% Cr brazing under the same material and the same joining conditions as in Example 2. This is an application of atmospheric brazing used in Patent Document 2. 7A shows a transmission X-ray image after joining of the joined body according to Comparative Example 2, and FIG. 7B shows the same enlarged cross-sectional secondary electron image along the XX line of FIG. 7A. . The same members as those in FIGS. 1 to 5 are denoted by the same reference numerals, and description thereof is omitted.
7A and 7B, it can be seen that in the case of the joined body of Comparative Example 2, there are more voids and the joining rate is significantly inferior compared to Example 2 and Comparative Example 1. Further, in FIG. 7A, it was confirmed that the surface of the metal plate was entirely white.

（実施例３）
次に、上記実施例１に係る接合体の気密性、耐高温水素性について説明する。
実施例１で得られた接合体の気密性は、Ｈｅリーク試験にて評価したところ、１０^−１１Ｐａ／ｓｅｃの優れた気密性を有していることが確認された。また、耐高温水素性を調査するため、図８に示すような実験系にて、接合体の内部に１ＮＬ／ｍｉｎの流量で水素（Ｈ_２）を流入し、８００℃大気中で４時間保持した。 (Example 3)
Next, the airtightness and high-temperature hydrogen resistance of the joined body according to Example 1 will be described.
When the airtightness of the joined body obtained in Example 1 was evaluated by a He leak test, it was confirmed that the bonded body had an excellent airtightness of 10 ⁻¹¹ Pa / sec. In order to investigate the high temperature hydrogen resistance, hydrogen (H ₂ ) was introduced into the joined body at a flow rate of 1 NL / min in an experimental system as shown in FIG. did.

試験後の接合体にスヌープリーク試験を行った結果、漏れは確認されず、更にＨｅリーク試験では１０^−８／ｓｅｃの優れた気密性を示した。なお、図８において、符番１１は大気炉１２に配置された接合体を、符番１３はＨ_２を流す配管を、符番１４はスウェージロックを示す。配管１３，スウェージロック１４及び接合体１１を通過したＨ_２を、大気炉外で燃焼させることにより、燃料電池の模擬的な運転環境を再現した。 As a result of conducting a snoop leak test on the joined body after the test, no leakage was confirmed, and the He leak test showed excellent airtightness of 10 ⁻⁸ / sec. In FIG. 8, reference numeral 11 indicates a joined body disposed in the atmospheric furnace 12, reference numeral 13 indicates a pipe through which H ₂ flows, and reference numeral 14 indicates a swage lock. The simulated operating environment of the fuel cell was reproduced by burning H ₂ that passed through the pipe 13, the swage lock 14, and the joined body 11 outside the atmospheric furnace.

図９は高温水素耐久試験前の接合体の断面二次電子像を示し、図９（Ａ）は接合体の全体図（×４０），図９（Ｂ）は中央部の拡大図（×３００），図９（Ｃ）は同接合体の中央部の拡大図（×１．００ｋ）を示す。また、図１０は試験後の接合体の断面二次電子像を示し、図１０（Ａ）は接合体の全体図（×４０），図１０（Ｂ）は接合体の水素雰囲気側拡大図（×５００），図１０（Ｃ）は接合体の中央部の拡大図（×５００），図１０（Ｄ）は接合体の大気雰囲気側の拡大図（×５００）を示す。なお、図１０（Ｄ）では、水素の拡散が早いので空洞が生じやすいことが確認できた。 FIG. 9 shows a cross-sectional secondary electron image of the joined body before the high-temperature hydrogen durability test, FIG. 9A is an overall view (× 40) of the joined body, and FIG. 9B is an enlarged view of the center portion (× 300). ) And FIG. 9C are enlarged views (× 1.00 k) of the central portion of the joined body. FIG. 10 shows a cross-sectional secondary electron image of the joined body after the test, FIG. 10A is an overall view (× 40) of the joined body, and FIG. 10B is an enlarged view of the joined body on the hydrogen atmosphere side ( × 500), FIG. 10C is an enlarged view (× 500) of the central portion of the joined body, and FIG. 10D is an enlarged view (× 500) of the joined body on the air atmosphere side. Note that in FIG. 10D, it was confirmed that cavities were easily generated because hydrogen diffused quickly.

図１１及び図１２（Ａ）〜（Ｆ）は、試験後の元素分布分析結果を示し、図１１は接合体の全体図を示す。図１１において、符番２１はセラミック製のセル、符番２２はろう材層、符番２３は金属（日立金属製の商品名：ＺＭＧ２３２Ｌ）の筒状体を示す。図１２（Ａ）ではＦｅ，図１２（Ｂ）ではＺｒ，図１２（Ｃ）ではＯ，図１２（Ｄ）ではＡｇ，図１２（Ｅ）ではＧｅ，図１２（Ｆ）ではＣｒの分析を行った。 11 and 12A to 12F show the element distribution analysis results after the test, and FIG. 11 shows an overall view of the joined body. In FIG. 11, reference numeral 21 denotes a ceramic cell, reference numeral 22 denotes a brazing material layer, and reference numeral 23 denotes a cylindrical body of metal (trade name: ZMG232L manufactured by Hitachi Metals). 12 (A), Fe in FIG. 12 (B), O in FIG. 12 (C), Ag in FIG. 12 (D), Ge in FIG. 12 (E), Cr in FIG. 12 (F). went.

分析結果より、金属板２３の領域では、フェライト系ＳＵＳの主成分であるＦｅ，Ｃｒが検出された。また、セル２１の領域では、主成分であるＺｒＯ_２が検出された。更に、ろう材層２２の領域では、主成分であるＡｇ，Ｇｅ，Ｃｒ，及びＧｅ，Ｃｒの酸化物が検出された。Ａｇ中にはＧｅ，Ｃｒが共存し、特にＧｅとＣｒの酸化物がセル２１上に反応層として形成されている。前記酸化物による反応層がセル２１との接合に寄与していると考えられる。更に、ろう材層２２と金属板２３の界面には、ＣｒとＯが共存しているのが認められる。このＣｒ酸化物が金属との反応層を形成して接合に寄与していると考えら得る。図１１及び図１２より、セル２１上にＧｅの酸化物層が形成されており、微量のＣｒも確認できた。また、ろう材の主成分のＡｇ中にＣｒが酸化物として点在している様子がわかった。 From the analysis result, in the region of the metal plate 23, Fe and Cr, which are the main components of ferrite SUS, were detected. Further, in the region of the cell 21, ZrO _{2 as} a main component was detected. Further, in the region of the brazing filler metal layer 22, the main components of Ag, Ge, Cr, and oxides of Ge and Cr were detected. Ge and Cr coexist in Ag. In particular, an oxide of Ge and Cr is formed on the cell 21 as a reaction layer. It is considered that the reaction layer made of the oxide contributes to the bonding with the cell 21. Furthermore, it is recognized that Cr and O coexist at the interface between the brazing filler metal layer 22 and the metal plate 23. It can be considered that this Cr oxide contributes to the bonding by forming a reaction layer with the metal. 11 and 12, a Ge oxide layer was formed on the cell 21, and a trace amount of Cr could be confirmed. It was also found that Cr was scattered as an oxide in the main component Ag of the brazing material.

（比較例３）
次に、上記実施例３と同様のリーク試験をＡｇ−２ｗｔ％Ｃｕろうを用いて行った。試験前の気密性は、実施例３と同様、１０^−１１Ｐａ／ｓｅｃ台の優れた気密性を示した。しかし、試験後のスヌープリーク試験では漏れが確認された。従って、Ｈｅリーク試験を行うことができなかった。
図１３は比較例３の接合体の高温水素耐久試験前の断面二次電子像を示し、図１３（Ａ）は接合体の全体図（×４０），図１３（Ｂ）は接合体の中央部の拡大図（×３００），図１３（Ｃ）は接合体の中央部の拡大図（×１．００ｋ）を示す。また、図１４は高温水素耐久試験後の接合体の断面二次電子像を示し、図１４（Ａ）は接合体の全体図（×４０），図１４（Ｂ）は接合体の水素雰囲気側の拡大図（×５００），図１４（Ｃ）は接合体の中部の拡大図（×５００），図１４（Ｄ）は接合体の大気雰囲気側の拡大図（×５００）を示す。 (Comparative Example 3)
Next, a leak test similar to that of Example 3 was performed using Ag-2 wt% Cu brazing. The airtightness before the test showed excellent airtightness on the order of 10 ⁻¹¹ Pa / sec as in Example 3. However, leaks were confirmed in the snoop leak test after the test. Therefore, the He leak test could not be performed.
FIG. 13 shows a cross-sectional secondary electron image of the joined body of Comparative Example 3 before the high-temperature hydrogen durability test, FIG. 13 (A) is an overall view of the joined body (× 40), and FIG. 13 (B) is the center of the joined body. Enlarged view (× 300) and FIG. 13 (C) are enlarged views (× 1.00 k) of the central part of the joined body. 14 shows a cross-sectional secondary electron image of the joined body after the high-temperature hydrogen durability test, FIG. 14 (A) is an overall view of the joined body (× 40), and FIG. 14 (B) is the hydrogen atmosphere side of the joined body. FIG. 14 (C) is an enlarged view (× 500) of the middle part of the joined body, and FIG. 14 (D) is an enlarged view (× 500) of the joined body on the atmosphere side.

（比較例４）
次に、上記実施例３と同様のリーク試験をＡｇ−１ｗｔ％ＴｉＡｌ−０．６ｗｔ％Ｃｒろうを用いて行った。試験前の気密性は、実施例３と同様、１０^−１１Ｐａ／ｓｅｃ台の優れた気密性を示した。しかし、試験後のスヌープリーク試験では、比較例３と同様に漏れが確認された。従って、Ｈｅリーク試験を行うことができなかった。
図１５は比較例４に係る接合体の高温水素耐久試験前の断面二次電子像を示し、図１５（Ａ）は接合体の全体図（×４０），図１５（Ｂ）は接合体の中央部の拡大図（×３００），図１５（Ｃ）は接合体の中央部の拡大図（×２．００ｋ）を示す。また、図１４は比較例４に係る接合体の高温水素耐久試験後の断面二次電子像を示し、図１６（Ａ）は接合体の全体図（×４０），図１６（Ｂ）は接合体の水素雰囲気側の拡大図（×５００），図１６（Ｃ）は接合体の中部の拡大図（×５００），図１６（Ｄ）は接合体の大気雰囲気側の拡大図（×５００）を示す。 (Comparative Example 4)
Next, a leak test similar to that of Example 3 was performed using Ag-1 wt% TiAl-0.6 wt% Cr brazing. The airtightness before the test showed excellent airtightness on the order of 10 ⁻¹¹ Pa / sec as in Example 3. However, in the snoop leak test after the test, leakage was confirmed as in Comparative Example 3. Therefore, the He leak test could not be performed.
15 shows a cross-sectional secondary electron image of the joined body according to Comparative Example 4 before the high-temperature hydrogen durability test, FIG. 15A is an overall view (× 40) of the joined body, and FIG. An enlarged view (× 300) of the central portion and FIG. 15 (C) show an enlarged view (× 2.00 k) of the central portion of the joined body. 14 shows a cross-sectional secondary electron image after the high-temperature hydrogen durability test of the joined body according to Comparative Example 4, FIG. 16A is an overall view of the joined body (× 40), and FIG. Fig. 16C is an enlarged view of the middle part of the joined body (x500), and Fig. 16D is an enlarged view of the joined body on the air atmosphere side (x500). Indicates.

下記表１は、上記実施例２及び比較例１，２のろう材組成及び接合率の良，不良の結果を示す。下記表２は、上記実施例３及び比較例３，４のろう材組成、Ｈｅリーク試験、スヌープリーク試験、ろう材層のボイド及び接合界面の剥離の有無を示す。表１より実施例２の場合は接合率が比較例２に比べて良好であることが確認できた。表２より、実施例３は比較例３，４に比べてＨｅリーク試験，スヌープリーク試験においてリークがなく、またろう材層のボイド及び接合界面の剥離もなく優れていることが確認できた。

Table 1 below shows the results of good and bad brazing material compositions and joining rates in Example 2 and Comparative Examples 1 and 2. Table 2 below shows the brazing material composition, the He leak test, the snoop leak test, the voids of the brazing material layer, and the presence or absence of peeling at the joint interface in Example 3 and Comparative Examples 3 and 4. From Table 1, it was confirmed that the bonding rate in Example 2 was better than that in Comparative Example 2. From Table 2, it was confirmed that Example 3 was superior to Comparative Examples 3 and 4 in that there was no leakage in the He leak test and snoop leak test, and there was no void in the brazing material layer and no peeling of the bonding interface.

（実施例４）
下記表３に示す組成のろう材１〜６で実施例３と同様の試験を行い、気密性の評価及び断面観察を行った。下記表４はろう材１〜６のろう材組成、Ｈｅリーク試験、スヌープリーク試験、ろう材層のボイド及び接合界面の剥離の有無を示す。表３，４より、ろう材１〜４の場合は、Ｈｅリーク試験，スヌープリーク試験においてリークがない。しかし、ろう材３，４の場合はろう材層のボイドがなく且つ接合界面の剥離がないが、ろう材１，２の場合はろう材の組成としてＣｒを含まないため、ろう材層のボイドが発生し且つ接合界面の剥離が確認された。

Example 4
The same tests as in Example 3 were performed on the brazing filler metals 1 to 6 having the compositions shown in Table 3 below, and airtightness evaluation and cross-sectional observation were performed. Table 4 below shows the brazing filler metal compositions of the brazing filler metals 1 to 6, the He leak test, the snoop leak test, the voids of the brazing filler metal layer, and the presence or absence of delamination of the bonding interface. From Tables 3 and 4, in the case of the brazing materials 1 to 4, there is no leak in the He leak test and the snoop leak test. However, in the case of the

brazing filler metals

3 and 4, there is no void in the brazing filler metal layer and there is no separation of the bonding interface, but in the case of the

brazing filler metals

1 and 2, the composition of the brazing filler metal does not contain Cr. Occurred and peeling of the bonding interface was confirmed.

（実施例５）
１．２ｍｍ厚の金属板（日立金属製の商品名：ＺＭＧ２３２Ｌ）３１を１５×１００ｍｍに切断し、接合代が１５ｍｍ角になるように、重ねろう付継手を、大気中９７０℃で３０分保持することで製作した。ろう付後、図１７に示すような引張試験を行った結果、ｎ＝３の平均引張強度は１１４ＭＰａを示した。 (Example 5)
A 1.2 mm thick metal plate (Hitachi Metals' trade name: ZMG232L) 31 is cut to 15 × 100 mm, and the overlap brazed joint is held at 970 ° C. for 30 minutes in the atmosphere so that the joining margin is 15 mm square. I made it. After brazing, a tensile test as shown in FIG. 17 was performed. As a result, the average tensile strength at n = 3 was 114 MPa.

（比較例５）
実施例５と同様の試験を、Ａｇ−２ｗｔ％Ｃｕろうを用いて行った。 (Comparative Example 5)
A test similar to that of Example 5 was performed using Ag-2 wt% Cu brazing.

（比較例６）
実施例５と同様の試験を、Ａｇ−１ｗｔ％ＴｉＡｌ−０．６ｗｔ％Ｃｒを用いて行った。
下記表５は、上記実施例５及び比較例５，６のろう材組成及び引張応力を示す。表５より、実施例５は比較例５，６に比べて引張応力が著しく優れていることが確認できた。

(Comparative Example 6)
The test similar to Example 5 was done using Ag-1 wt% TiAl-0.6 wt% Cr.
Table 5 below shows the brazing material composition and tensile stress of Example 5 and Comparative Examples 5 and 6. From Table 5, it was confirmed that Example 5 was significantly superior in tensile stress as compared with Comparative Examples 5 and 6.

なお、この発明は、上記実施例のような金属部材とセラミックスの接合に限らず、セラミックス同士の接合、又は金属部材同士の接合に適用できる。また、ろう材の組み合わせも上記実施例に記載したものに限らず、［発明を実施するための最良の形態］で述べた様々な材料を用いることができる。更に、加熱条件も上記実施例に記載されたものに限らず、本発明の要旨を変更しない範囲で適宜組み合わせることができる。
以下に、本願出願の当初の特許請求の範囲に記載された発明を付記する。
［１］主成分であるＡｇと、Ｇｅ，Ｃｒ又はこれらの酸化物と、残部としての不可避不純物からなることを特徴とする大気接合用ろう材。
［２］Ａｇを８０〜９５ｗｔ％と、Ｇｅ又はＧｅ酸化物を０より多く１０ｗｔ％以下と、Ｃｒ又はＣｒ酸化物を０．２〜１０ｗｔ％以下と、残部としての不可避不純物からなり、これらの合計が１００ｗｔ％となるように調整されていることを特徴とする［１］記載の大気接合用ろう材。
［３］大気中の接合過程でＧｅとＣｒを主とする複合酸化物になることを特徴とする［１］若しくは［２］記載の大気接合用ろう材。
［４］セラミックス同士又はセラミックスと金属又は金属同士を、［１］乃至［３］何れか一記載の大気接合用ろう材で接合してなり、かつガスシール性を有することを特徴とする接合体。
［５］燃料電池用として使用されることを特徴とする［４］記載の接合体。
［６］固体酸化物型燃料電池として使用されることを特徴とする［４］記載の接合体。 In addition, this invention is applicable not only to the joining of a metal member and ceramics like the said Example but to joining of ceramics, or joining of metal members. The combination of the brazing materials is not limited to that described in the above embodiment, and various materials described in [Best Mode for Carrying Out the Invention] can be used. Furthermore, the heating conditions are not limited to those described in the above embodiments, and can be appropriately combined within a range not changing the gist of the present invention.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[1] A brazing material for air bonding, comprising Ag as a main component, Ge, Cr, or an oxide thereof, and an inevitable impurity as a balance.
[2] Ag is 80 to 95 wt%, Ge or Ge oxide is more than 0 and 10 wt% or less, Cr or Cr oxide is 0.2 to 10 wt% or less, and the balance is inevitable impurities. The brazing material for air bonding according to [1], wherein the total amount is adjusted to 100 wt%.
[3] The brazing material for air bonding according to [1] or [2], wherein a composite oxide mainly composed of Ge and Cr is formed in a bonding process in the air.
[4] A joined body comprising ceramics or ceramics and metal or metals joined together by the brazing material for air joining according to any one of [1] to [3], and having gas sealing properties. .
[5] The joined body according to [4], which is used for a fuel cell.
[6] The joined body according to [4], which is used as a solid oxide fuel cell.

１，２１…セル、２，２３…筒状体、３…パイプ、４，２２…大気ろう付部、５，３１…金属板、６…空洞部、７…はみ出したろう材、１１…接合体。 DESCRIPTION OF SYMBOLS 1,21 ... Cell, 2,23 ... Cylindrical body, 3 ... Pipe, 4,22 ... Air brazing part, 5,31 ... Metal plate, 6 ... Hollow part, 7 ... Extruding brazing material, 11 ... Joined body.

Claims

Ag is 94 to 97 wt % , Ge or Ge oxide is 1 to 5 wt% , Cr or Cr oxide is 1 to 3 wt%, and the balance is inevitable impurities, and the total of these is 100 wt% A brazing material for air bonding, characterized by being adjusted.

2. The brazing material for air bonding according to claim 1, wherein a composite oxide mainly composed of Ge and Cr is formed in a bonding process in the air.

A joined body comprising ceramics or ceramics and metal or metals joined together using the brazing material for air bonding according to claim 1 or 2, and having gas sealing properties.

4. The joined body according to claim 3, wherein the joined body is used for a fuel cell.

4. The joined body according to claim 3, wherein the joined body is used as a solid oxide fuel cell.