JPH04214069A - Lanthanum chromite-based multiple oxide and its application - Google Patents
Lanthanum chromite-based multiple oxide and its applicationInfo
- Publication number
- JPH04214069A JPH04214069A JP3067465A JP6746591A JPH04214069A JP H04214069 A JPH04214069 A JP H04214069A JP 3067465 A JP3067465 A JP 3067465A JP 6746591 A JP6746591 A JP 6746591A JP H04214069 A JPH04214069 A JP H04214069A
- Authority
- JP
- Japan
- Prior art keywords
- lanthanum chromite
- lanthanum
- oxide
- alkaline earth
- earth metal
- 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.)
- Pending
Links
- NFYLSJDPENHSBT-UHFFFAOYSA-N chromium(3+);lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Cr+3].[La+3] NFYLSJDPENHSBT-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims abstract description 13
- 150000001342 alkaline earth metals Chemical group 0.000 claims abstract description 13
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 8
- 239000011777 magnesium Substances 0.000 claims abstract description 8
- 239000000446 fuel Substances 0.000 claims description 14
- 239000002131 composite material Substances 0.000 claims description 11
- 239000004020 conductor Substances 0.000 claims description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 26
- 229910052742 iron Inorganic materials 0.000 abstract description 13
- 239000011651 chromium Substances 0.000 abstract description 11
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 abstract description 7
- 229910052804 chromium Inorganic materials 0.000 abstract description 7
- 229910052746 lanthanum Inorganic materials 0.000 abstract description 7
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 abstract description 7
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 11
- 239000000843 powder Substances 0.000 description 9
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum oxide Inorganic materials [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 description 8
- 239000000203 mixture Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000010304 firing Methods 0.000 description 5
- 239000007784 solid electrolyte Substances 0.000 description 5
- 238000001354 calcination Methods 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000002441 X-ray diffraction Methods 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 229910000423 chromium oxide Inorganic materials 0.000 description 3
- BDAGIHXWWSANSR-NJFSPNSNSA-N hydroxyformaldehyde Chemical compound O[14CH]=O BDAGIHXWWSANSR-NJFSPNSNSA-N 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N iron oxide Inorganic materials [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 3
- 239000011812 mixed powder Substances 0.000 description 3
- 239000004570 mortar (masonry) Substances 0.000 description 3
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 229910052712 strontium Inorganic materials 0.000 description 3
- 229910000018 strontium carbonate Inorganic materials 0.000 description 3
- 238000006467 substitution reaction Methods 0.000 description 3
- 229910000859 α-Fe Inorganic materials 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 2
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 229910052788 barium Inorganic materials 0.000 description 2
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 239000011575 calcium Substances 0.000 description 2
- 239000010941 cobalt Substances 0.000 description 2
- 229910017052 cobalt Inorganic materials 0.000 description 2
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229910002076 stabilized zirconia Inorganic materials 0.000 description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910002321 LaFeO3 Inorganic materials 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011195 cermet Substances 0.000 description 1
- UOUJSJZBMCDAEU-UHFFFAOYSA-N chromium(3+);oxygen(2-) Chemical class [O-2].[O-2].[O-2].[Cr+3].[Cr+3] UOUJSJZBMCDAEU-UHFFFAOYSA-N 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002019 doping agent Substances 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 239000002737 fuel gas Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910000473 manganese(VI) oxide Inorganic materials 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- -1 oxygen ion Chemical class 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005204 segregation Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0215—Glass; Ceramic materials
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0215—Glass; Ceramic materials
- H01M8/0217—Complex oxides, optionally doped, of the type AMO3, A being an alkaline earth metal or rare earth metal and M being a metal, e.g. perovskites
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/50—Fuel cells
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Sustainable Development (AREA)
- Sustainable Energy (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Fuel Cell (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Conductive Materials (AREA)
Abstract
Description
【０００１】0001
【産業上の利用分野】本発明は新規なランタンクロマイ
ト系複合酸化物とその高温導電性材料及び高温型燃料電
池セパレータとしての用途に係る。この新規なランタン
クロマイト系複合酸化物は高導電性かつ緻密であり、高
温型燃料電池、ＭＨＤ発電その他の高温導電性材料に利
用することができる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new lanthanum chromite complex oxide and its use as a high temperature conductive material and a high temperature fuel cell separator. This new lanthanum chromite-based composite oxide is highly conductive and dense, and can be used for high-temperature fuel cells, MHD power generation, and other high-temperature conductive materials.
【０００２】0002
【従来の技術】ランタンクロマイト（ＬａＣｒＯ３ ）
は高温において導電性をもち、かつ耐酸化性、耐還元性
に優れるために、高温の腐食性雰囲気で使用する導体材
料として極めて有望視されている酸化物系セラミックス
である。ランタンクロマイトにマグネシウム、カルシウ
ム、ストロンチウム、バリウムなどのアルカリ土類金属
を微量不純物元素として添加することにより、ドーパン
トとして作用し導電率を向上させることができる。ラン
タンクロマイトはペロブスカイト構造ＡＢＯ３ （式中
、Ａ，Ｂは金属元素、Ｏは酸素である。）をなしている
。
添加したカルシウム、ストロンチウム、バリウムはラン
タンクロマイト格子中ランタン位置に置換固溶しており
、一方マグネシウムはクロム位置に置換固溶している。[Prior art] Lanthanum chromite (LaCrO3)
is an oxide-based ceramic that is highly promising as a conductive material for use in high-temperature corrosive atmospheres because it has electrical conductivity at high temperatures and has excellent oxidation and reduction resistance. By adding an alkaline earth metal such as magnesium, calcium, strontium, or barium to lanthanum chromite as a trace impurity element, it can act as a dopant and improve electrical conductivity. Lanthanum chromite has a perovskite structure ABO3 (wherein A and B are metal elements and O is oxygen). The added calcium, strontium, and barium are substituted in solid solution at the lanthanum position in the lanthanum chromite lattice, while magnesium is substituted in solid solution at the chromium position.
【０００３】0003
【発明が解決しようとする課題】上記、微量元素添加ラ
ンタンクロマイトは導電率の点では十分な性能を有して
いるが、常圧大気中では緻密な焼結が得られにくく空隙
が生じるためにガスを十分に遮断できないという欠点が
ある。したがって、例えば固体電解質燃料電池のセパレ
ータ材料としてランタンクロマイトを用いようとした場
合、燃料ガスと空気を完全に分離することが不可能であ
り、この目的に用いることができなかった。[Problem to be solved by the invention] Although the above-mentioned lanthanum chromite with added trace elements has sufficient performance in terms of electrical conductivity, it is difficult to obtain dense sintering in normal pressure atmosphere, and voids occur. The disadvantage is that the gas cannot be shut off sufficiently. Therefore, for example, when attempting to use lanthanum chromite as a separator material for a solid electrolyte fuel cell, it is impossible to completely separate fuel gas and air, and it cannot be used for this purpose.
【０００４】ランタンクロマイトにおいて容易に緻密な
焼結体が得られないのは、第一に焼成温度において酸化
クロムの蒸気圧が高く、ランタンクロマイトの分解によ
って生じた酸化クロム蒸気が焼結体粒界における気孔の
移動を阻害するため、焼結体中に微細な空隙として残留
するためであり（工業材料１９８７年１１月号別冊、１
８ページ）、第二にイオンの体積拡散がきわめて遅く原
料粉末の界面が移動しにくいためである。[0004] The reason why it is not easy to obtain a dense sintered body in lanthanum chromite is that the vapor pressure of chromium oxide is high at the sintering temperature, and the chromium oxide vapor generated by the decomposition of lanthanum chromite flows into the grain boundaries of the sintered body. This is because they remain as fine voids in the sintered body to inhibit the movement of pores in the sintered body (Industrial Materials, November 1987 issue, special issue, 1).
(page 8), and secondly, the volumetric diffusion of ions is extremely slow and the interface of the raw material powder is difficult to move.
【０００５】そこで、本発明はこの点を解決し緻密な焼
結体を常圧大気中で容易に得られるようにするとともに
、導電率においても従来よりも向上せしめることを目的
とする。The object of the present invention is therefore to solve this problem and to make it possible to easily obtain a dense sintered body in normal pressure atmosphere, as well as to improve the electrical conductivity compared to the conventional one.
【０００６】[0006]
【課題を解決するための手段】本発明者らは、上記目的
を達成するために、先に、ランタンクロマイトのランタ
ンの１部をアルカリ土類金属で置換し、クロムの１部を
コバルトで置換した新規なランタンクロマイト系複合酸
化物を開示した（特願平１−１９６７８５号）。そして
、上記において、コバルトに代えて、鉄でクロムの１部
を置換した場合にも同様の効果が奏せられることを見い
出し、本発明に到達した。[Means for Solving the Problems] In order to achieve the above object, the present inventors first replaced a part of lanthanum in lanthanum chromite with an alkaline earth metal, and replaced a part of chromium with cobalt. A novel lanthanum chromite-based composite oxide has been disclosed (Japanese Patent Application No. 196785/1999). In the above, it has been found that the same effect can be achieved even when a part of chromium is replaced with iron instead of cobalt, and the present invention has been achieved.
【０００７】こうして、本発明は、上記目的を達成する
ために、一般式Ｌａ１−ｘ Ｍｘ Ｃｒ１−ｙ Ｆｅｙ
Ｏ３ （式中、Ｍはマグネシウムを除くアルカリ土類
金属であり、０＜ｘ≦０．５であり、０＜ｙ≦０．５で
ある。）で表わされかつペロブスカイト構造を持つこと
を特徴とする新規なランタンクロマイト系複合酸化物を
提供する。同様にして、本発明は、一般式（Ｌａ１−ｘ
Ｍｘ ）ａ （Ｃｒ１−ｙ Ｆｅｙ ）ｂ Ｏ３ 〔
式中、Ｍはマグネシウムを除くアルカリ土類金属であり
、０＜ｘ≦０．５，０＜ｙ≦０．５、そして０．９５≦
ｂ／ａ＜１又は１＜ｂ／ａ≦１．０５である。〕で表わ
され主としてペロブスカイト構造からなることを特徴と
するランタンクロマイト系複合酸化物を提供する。[0007] Thus, in order to achieve the above object, the present invention provides the general formula La1-x Mx Cr1-y Fey
O3 (wherein M is an alkaline earth metal excluding magnesium, 0<x≦0.5, and 0<y≦0.5) and is characterized by having a perovskite structure. A novel lanthanum chromite-based composite oxide is provided. Similarly, the present invention provides the general formula (La1-x
Mx )a (Cr1-y Fey)b O3 [
In the formula, M is an alkaline earth metal excluding magnesium, 0<x≦0.5, 0<y≦0.5, and 0.95≦
b/a<1 or 1<b/a≦1.05. The present invention provides a lanthanum chromite-based composite oxide represented by the following formula, characterized in that it mainly consists of a perovskite structure.
【０００８】さらに、本発明によれば、上記のランタン
クロマイト系複合酸化物を用いた高温導電性材料及び高
温型燃料電池のセパレータを提供する。一般式Ｌａ１−
ｘ Ｍｘ Ｃｒ１−ｙ Ｆｅｙ Ｏ３ で表わされるペ
ロブスカイト構造を持つランタンクロマイト系複合酸化
物は、最も理想的には、ペロブスカイト型（ＡＢＯ３
）構造のＡサイトにＬａ、ＢサイトにＣｒが配置したラ
ンタンクロマイトの基本構造において、Ｌａの一部がア
ルカリ土類金属で置換され、かつさらにＣｒの一部がＦ
ｅで置換された構造をなしていると考えられる。Furthermore, the present invention provides a high-temperature conductive material and a separator for a high-temperature fuel cell using the above-mentioned lanthanum chromite-based composite oxide. General formula La1-
The lanthanum chromite-based composite oxide having a perovskite structure represented by
) In the basic structure of lanthanum chromite, in which La is placed at the A site and Cr is placed at the B site, a part of La is replaced with an alkaline earth metal, and a part of Cr is further replaced with F.
It is thought that it has a structure substituted with e.
【０００９】また、一般式（Ｌａ１−ｘ Ｍｘ ）ａ
（Ｃｒ１−ｙ Ｆｅｙ ）ｂ Ｏ３ で表わされる主と
してペロブスカイト構造からなるランタンクロマイト系
複合酸化物は、上記のペロブスカイト構造（ｂ／ａ＝１
の場合）からｂ／ａが僅かにずれた分だけ、ペロブスカ
イト構造以外の構造が含まれていると考えられる。Ｌａ
の一部をアルカリ土類金属で置換することによって導電
性が向上する。ただし、マグネシウムはＡサイトのＬａ
ではなくＢサイトのＣｒと置換するので、本発明では用
いない。アルカリ土類金属の置換量は、モル比で０．５
まで、好ましくは０．０５〜０．３である。これらのア
ルカリ土類金属による置換がこの範囲内で多いほど導電
性は高くなるが、この範囲を越えて増加するともはやＬ
ａと置換しきれなくなり、ペロブスカイト構造以外の複
合酸化物（例えばＣａＣｒＯ４ ，ＳｒＣｒＯ４ など
）を生じ、その特性を著しく低下させる。[0009] Furthermore, the general formula (La1-x Mx)a
The lanthanum chromite-based composite oxide mainly consisting of a perovskite structure represented by (Cr1-y Fey)b O3 has the above-mentioned perovskite structure (b/a=1
It is considered that a structure other than the perovskite structure is included by the amount that b/a slightly deviates from the case of . La
Conductivity is improved by replacing a portion of with an alkaline earth metal. However, magnesium is La at the A site.
However, it is not used in the present invention because it is substituted with Cr at the B site. The amount of alkaline earth metal substitution is 0.5 in molar ratio.
up to, preferably 0.05 to 0.3. The more substitutions with these alkaline earth metals within this range, the higher the conductivity becomes, but when it increases beyond this range, it is no longer L.
This results in the formation of complex oxides other than perovskite structures (eg, CaCrO4, SrCrO4, etc.), which significantly deteriorates the properties.
【００１０】鉄はランタンクロマイト格子のＢサイトの
クロムの一部と置換して酸化クロムの蒸気圧を下げ、そ
の蒸発を抑制するために緻密な焼結体を得ることが可能
になる。また、鉄の添加は又、焼結体の導電率を向上さ
せる効果があり、鉄を添加しない場合に較べ高い導電率
が得られる。鉄の置換量はモル比で０＜ｙ≦０．５、よ
り好ましくは０．０５≦ｙ≦０．３である。鉄の添加量
が多くなると、ランタンクロマイト格子中への固溶が困
難になり、ランタンフェライト（ＬａＦｅＯ３ ）が生
成するようになる。ランタンフェライトは電子導電性の
ほかに酸素イオン導電性を有し、また、還元性雰囲気下
で不安定なのでランタンクロマイトとしての特性を劣化
させる。従って、鉄の添加量はランタンフェライトが生
成しない量か、生成してもその量ができるだけ少ないこ
とが望ましい。[0010] Iron replaces part of the chromium at the B site of the lanthanum chromite lattice, lowering the vapor pressure of chromium oxide and suppressing its evaporation, making it possible to obtain a dense sintered body. Further, the addition of iron also has the effect of improving the electrical conductivity of the sintered body, and a higher electrical conductivity can be obtained than when no iron is added. The amount of iron substitution is such that the molar ratio is 0<y≦0.5, more preferably 0.05≦y≦0.3. When the amount of iron added increases, solid solution in the lanthanum chromite lattice becomes difficult, and lanthanum ferrite (LaFeO3) is generated. Lanthanum ferrite has oxygen ion conductivity in addition to electronic conductivity, and is unstable in a reducing atmosphere, which deteriorates the properties of lanthanum chromite. Therefore, it is desirable that the amount of iron added be such that no lanthanum ferrite is produced, or that even if it is produced, the amount is as small as possible.
【００１１】一般式（Ｌａ１−ｘ Ｍｘ ）ａ （Ｃｒ
１−ｙ Ｆｅｙ ）ｂ Ｏ３ においてｂ／ａは必ずし
も１である必要はなく、その前後でも同様な効果を奏す
ることができるが、ｂ／ａを１から若干ずらした場合に
はセラミックスの強度を向上する効果を奏する。本発明
の材料は特にＦｅの添加により焼結性に優れ、緻密な焼
結体を得ることができるが、焼結体は多結晶より構成さ
れており、一般的に焼結性の向上は結晶粒径の拡大を促
し、結晶粒径が大きくなるにつれてセラミックス強度が
低下する。これはアルミナや安定化ジルコニアにおいて
もよく知られた現象である。そこで、ｂ／ａの比を１か
ら若干ずらすことによって、多結晶中にペロブスカイト
構造以外の構造を入れることで、粒径を抑制し、これに
よってセラミックス強度の向上を図ることができる。但
し、ｂ／ａが１からあまり大きくずれてしまうと、ペロ
ブスカイト構造以外のランタン酸化物やクロム酸化物な
どが増加し、これらは粒子界面にあって電気導電性を低
下させるので好ましくない。そこで、ｂ／ａは０．９５
〜１．０５の範囲内とする。General formula (La1-x Mx ) a (Cr
1-y Fey )b In O3, b/a does not necessarily have to be 1, and the same effect can be achieved even before or after that, but if b/a is slightly shifted from 1, the strength of the ceramic will be improved. It has the effect of The material of the present invention has excellent sinterability due to the addition of Fe, and a dense sintered body can be obtained, but the sintered body is composed of polycrystals, and generally the improvement in sinterability is due to crystallization. It promotes grain size expansion, and as the crystal grain size increases, the ceramic strength decreases. This is a well-known phenomenon in alumina and stabilized zirconia. Therefore, by slightly shifting the b/a ratio from 1 and introducing a structure other than the perovskite structure into the polycrystal, the grain size can be suppressed, thereby improving the ceramic strength. However, if b/a deviates too much from 1, lanthanum oxides, chromium oxides, etc. other than the perovskite structure increase, which is not preferable because they are present at the particle interface and reduce electrical conductivity. Therefore, b/a is 0.95
-1.05.
【００１２】本発明の新規なランタンクロマイト系複合
酸化物の製造手法自体は慣用法に従うことができる。す
なわち、ランタン源、アルカリ土類金属源、クロム源、
鉄源を所定比に混合した粉末混合物を所定の温度、一般
的には、１０００〜１６００℃、好ましくは１０００〜
１２００℃で仮焼して得ることができる。仮焼時間は一
般に１〜数十時間、好ましくは１〜１０時間である。仮
焼雰囲気は大気中等の酸素含有雰囲気中で行なう。仮焼
時の圧力は大気圧でよい。The novel lanthanum chromite complex oxide of the present invention can be manufactured by any conventional method. Namely, lanthanum source, alkaline earth metal source, chromium source,
A powder mixture containing iron sources in a predetermined ratio is heated to a predetermined temperature, generally 1000 to 1600°C, preferably 1000 to 1000°C.
It can be obtained by calcining at 1200°C. The calcination time is generally 1 to several tens of hours, preferably 1 to 10 hours. The calcination atmosphere is performed in an oxygen-containing atmosphere such as the air. The pressure during calcination may be atmospheric pressure.
【００１３】仮焼粉末の成形、焼成も慣用法に従うこと
ができるが、焼成温度は一般に１３００℃以上で、好ま
しくは１５００〜１６００℃、焼成時間は焼成体の形状
に依存するが一般に１〜１０時間、好ましくは１〜２時
間、焼成雰囲気は酸素含有雰囲気である。本発明のラン
タンクロマイト系複合酸化物は常圧焼結でも緻密な焼結
体が得られることを特徴としているが、加圧下で焼結す
ることを排斥するわけではない。[0013] Molding and firing of the calcined powder can also be carried out according to conventional methods, but the firing temperature is generally 1300°C or higher, preferably 1500 to 1600°C, and the firing time is generally 1 to 10°C, although it depends on the shape of the fired product. The firing atmosphere is an oxygen-containing atmosphere for a period of time, preferably 1 to 2 hours. Although the lanthanum chromite-based composite oxide of the present invention is characterized in that a dense sintered body can be obtained even by normal pressure sintering, sintering under pressure is not excluded.
【００１４】こうして得られる微量元素添加ランタンク
ロマイト焼結体は、常圧大気中における焼成によっても
８５％以上の相対密度を得ることができ、かつ導電率も
従来組成のものと比較して１５％以上高い値を得ること
ができる。しかも、この焼結体は耐酸化性、耐還元性に
優れているので、高温下で耐食性と導電性の両方が要求
される高温導電性材料として有用である。とくに、導電
性を有しかつ耐食性と緻密性を有する点で、固体電解質
型燃料電池のセパレータ材料として有用である。The trace element-added lanthanum chromite sintered body obtained in this way can obtain a relative density of 85% or more even when fired in the atmosphere at normal pressure, and has an electrical conductivity of 15% compared to that of the conventional composition. higher values can be obtained. Moreover, since this sintered body has excellent oxidation resistance and reduction resistance, it is useful as a high-temperature conductive material that requires both corrosion resistance and conductivity at high temperatures. In particular, it is useful as a separator material for solid oxide fuel cells because it has electrical conductivity, corrosion resistance, and denseness.
【００１５】図１にプラナー型固体電解質燃料電池の構
造の例を示す。同図中、１は固体電解質（例、Ｙ安定化
ジルコニア）のシートで上面にカソード（例、Ｌａ０．
９ Ｓｒ０．１ ＭｎＯ３ ）２、下面にアノード（例
、ＮｉＯ／ＺｒＯ２ サーメット）３が形成されている
。４がセパレータで本発明の新規なランタンクロマイト
系複合酸化物で作る。５は４と同じくランタンクロマイ
ト系複合酸化物で作るが、外部出力端子として使われる
。図１に見られる通り、セパレータ４はそれに形成され
た溝によって空気６及び燃料（例、水素）７の流路を構
成しかつ空気６と燃料７を分離するセパレータであると
共に、隣接する単位セルのアノード３とカソード２とを
電気的に接続する役割をも担うものである。外部出力端
子５は集積された単位セルの両端部において空気６と燃
料７の流路を形成すると共にアノード３又はカソード２
との電気的接続を行なう部材でもあり、これも本発明の
ランタンクロマイト系複合酸化物で構成する。また、図
１は２つの単位セルを集積した燃料電池を示したが、３
つ以上の単位セルを集積することも可能で、その場合に
は各単位セル間にセパレータ４を挿入する。FIG. 1 shows an example of the structure of a planar solid electrolyte fuel cell. In the figure, 1 is a sheet of solid electrolyte (eg, Y-stabilized zirconia) with a cathode (eg, La0.
9 Sr0.1 MnO3 ) 2, and an anode (eg, NiO/ZrO2 cermet) 3 is formed on the lower surface. 4 is a separator made of the novel lanthanum chromite complex oxide of the present invention. 5 is made of lanthanum chromite complex oxide like 4, but is used as an external output terminal. As seen in FIG. 1, the separator 4 is a separator that forms a flow path for air 6 and fuel (e.g. hydrogen) 7 by grooves formed therein, and separates the air 6 and fuel 7 from adjacent unit cells. It also plays the role of electrically connecting the anode 3 and cathode 2 of. The external output terminal 5 forms a flow path for air 6 and fuel 7 at both ends of the integrated unit cell, and also connects to the anode 3 or cathode 2.
It is also a member for electrical connection with the lanthanum chromite complex oxide of the present invention. In addition, although Fig. 1 shows a fuel cell in which two unit cells are integrated, three
It is also possible to integrate more than one unit cell, in which case a separator 4 is inserted between each unit cell.
【００１６】[0016]
【実施例】実施例１（ｂ／ａ＝１）
酸化ランタン２６．０６５ｇ、炭酸ストロンチウム５．
９０５ｇ、酸化第二ク
ロム１３．６７９ｇ、酸化第二鉄１．５９７ｇを秤量し
、メノウ乳鉢を用いて湿式混合した。この組成はＬａ０
．８ Ｓｒ０．２ Ｃｒ０．９ Ｆｅ０．１ Ｏ３ に
相当する。この混合粉末を１２００℃にて１時間仮焼し
た。昇温速度は２０℃／ｍｉｎである。こうして得られ
たランタンクロマイト粉末をＸ線回折法により分析した
結果、第二相の存在は確認できず、鉄はペロブスカイト
構造をもったランタンクロマイト格子中に固溶している
ことがわかった。[Example] Example 1 (b/a=1) 26.065 g of lanthanum oxide, 5.0 g of strontium carbonate.
905 g of chromic oxide, 13.679 g of chromic oxide, and 1.597 g of ferric oxide were weighed and wet-mixed using an agate mortar. This composition is La0
．． 8 Sr0.2 Cr0.9 Fe0.1 O3. This mixed powder was calcined at 1200°C for 1 hour. The temperature increase rate is 20°C/min. As a result of analyzing the thus obtained lanthanum chromite powder by X-ray diffraction, the presence of a second phase could not be confirmed, and it was found that iron was solidly dissolved in the lanthanum chromite lattice having a perovskite structure.
【００１７】この粉末を３００ｋｇｆ／ｃｍ２ の荷重
でフローティング成形し、１６００℃にて２時間本焼成
した（昇温速度は５℃／ｍｉｎ）。こうして得られた焼
結体について、密度ならびに導電率を測定した。その結
果、密度にして５．６ｇ／ｃｍ３ 、空気中１０００℃
における導電率にして２１Ｓ／ｃｍを得た。また、この
焼結体を走査型電子顕微鏡ならびにＥＤＸ分光分析によ
って元素の分布を観察したが、偏析等は見られず添加し
た鉄は均一にクロムと置換していることがわかった。[0017] This powder was float-molded under a load of 300 kgf/cm2, and main firing was performed at 1600°C for 2 hours (heating rate was 5°C/min). The density and conductivity of the sintered body thus obtained were measured. As a result, the density was 5.6g/cm3, and the temperature was 1000℃ in air.
A conductivity of 21 S/cm was obtained. In addition, the element distribution of this sintered body was observed using a scanning electron microscope and EDX spectroscopy, and no segregation was observed, indicating that the added iron was uniformly replaced by chromium.
【００１８】以上のものと同製法にて作製したＬａ０．
８ Ｓｒ０．２ ＣｒＯ３ 組成の焼結体（比較例）に
おいては密度５．０ｇ／ｃｍ３ 、空気中１０００℃に
おける導電率にして１８Ｓ／ｃｍであった。このように
、鉄を添加することによって密度、導電率ともに向上し
ていることがわかる。
実施例２（ｂ／ａ＝０．９７）
酸化ランタン２６．０６５ｇ、炭酸ストロンチウム５．
９０５ｇ、酸化第二クロム１３．２６９ｇおよび酸化第
二鉄１．５４９ｇを秤量し、メノウ乳鉢を用いて湿式混
合した。この組成はＬａ０．８ Ｓｒ０．２ Ｃｒ０．
８７３ Ｆｅ０．０９７ Ｏ３ に相当する。この混合
粉末を実施例１と同様にして焼成した。[0018] La0.
The sintered body (comparative example) having a composition of 8 Sr0.2 CrO3 had a density of 5.0 g/cm 3 and a conductivity of 18 S/cm at 1000° C. in air. Thus, it can be seen that both density and conductivity are improved by adding iron. Example 2 (b/a=0.97) 26.065 g of lanthanum oxide, 5.0 g of strontium carbonate.
905 g of chromic oxide, 13.269 g of chromic oxide, and 1.549 g of ferric oxide were weighed and wet-mixed using an agate mortar. This composition is La0.8 Sr0.2 Cr0.
It corresponds to 873 Fe0.097 O3. This mixed powder was fired in the same manner as in Example 1.
【００１９】得られた焼成生成物（粉末）はＸ線回折法
により分析すると、殆んどペロブスカイト構造であった
。この粉末を用いて実施例１と同様にして焼結体を調製
し、密度、導電率、曲げ強度、平均粒径を測定した。
結果を表１に示す。
実施例３（ｂ／ａ＝１．０２）
酸化ランタン２６．０６５ｇ、炭酸ストロンチウム５．
９０５ｇ、酸化第二クロム１３．９５２ｇおよび酸化第
二鉄１．６２９ｇを秤量し、メノウ乳鉢を用いて湿式混
合した。この組成はＬａ０．８ Ｓｒ０．２ Ｃｒ０．
９１８ Ｆｅ０．１０２ Ｏ３ に相当する。この混合
粉末を実施例１と同様にして焼成した。When the obtained fired product (powder) was analyzed by X-ray diffraction, it was found that most of it had a perovskite structure. A sintered body was prepared using this powder in the same manner as in Example 1, and the density, electrical conductivity, bending strength, and average particle size were measured. The results are shown in Table 1. Example 3 (b/a=1.02) 26.065 g of lanthanum oxide, 5.0 g of strontium carbonate.
905 g of chromic oxide, 13.952 g of chromic oxide, and 1.629 g of ferric oxide were weighed and wet-mixed using an agate mortar. This composition is La0.8 Sr0.2 Cr0.
It corresponds to 918 Fe0.102 O3. This mixed powder was fired in the same manner as in Example 1.
【００２０】得られた焼成生成物（粉末）はＸ線回折法
により分析すると、殆んどペロブスカイト構造であった
。この粉末を用いて実施例１と同様にして焼結体を調製
し、密度、導電率、曲げ強度、平均粒径を測定した。
結果を表１に示す。[0020] When the obtained fired product (powder) was analyzed by X-ray diffraction, it was found that most of it had a perovskite structure. A sintered body was prepared using this powder in the same manner as in Example 1, and the density, electrical conductivity, bending strength, and average particle size were measured. The results are shown in Table 1.
【００２１】[0021]
【表１】[Table 1]
【００２２】表１の結果より、Ｓｒ及びＦｅの添加によ
り焼結体の密度（焼結性）、導電率ともに向上している
こと、またＡサイト、Ｂサイトの組成比ｂ／ａを１から
若干ずらすことにより機械的強度が向上し、かつ密度、
導電率は損なわれていないことが見られる。From the results in Table 1, it can be seen that both the density (sinterability) and electrical conductivity of the sintered body are improved by adding Sr and Fe, and that the composition ratio b/a of the A site and B site is changed from 1 to 1. By slightly shifting the mechanical strength and density,
It can be seen that the conductivity is intact.
【００２３】[0023]
【発明の効果】本発明により提供される新規ランタンク
ロマイト系複合酸化物は、常圧大気中で容易に緻密化し
、かつ導電率も優れているので、高温で使用する安定な
導体材料を提供することができ、とくに高温型燃料電池
のセパレータとして有用である。[Effects of the Invention] The novel lanthanum chromite-based composite oxide provided by the present invention is easily densified in normal pressure atmosphere and has excellent electrical conductivity, so it provides a stable conductor material that can be used at high temperatures. It is particularly useful as a separator for high-temperature fuel cells.
【図１】平板型固体電解質型燃料電池の模式図である。FIG. 1 is a schematic diagram of a flat plate solid electrolyte fuel cell.
１…固体電解質 ２…カソード ３…アノード ４…接合体 ５…外部出力端子 ６…空気 ７…燃料 1...Solid electrolyte 2...Cathode 3...Anode 4...Zygote 5...External output terminal 6...Air 7...Fuel
Claims (4)
Ｆｅｙ Ｏ３ （式中、Ｍはマグネシウムを除くアル
カリ土類金属であり、０＜ｘ≦０．５であり、０＜ｙ≦
０．５である。）で表わされかつペロブスカイト構造を
持つことを特徴とするランタンクロマイト系複合酸化物
。Claim 1: General formula La1-x Mx Cr1-y
Fey O3 (where M is an alkaline earth metal excluding magnesium, 0<x≦0.5, and 0<y≦
It is 0.5. ) is a lanthanum chromite-based composite oxide characterized by having a perovskite structure.
Ｃｒ１−ｙ Ｆｅ）ｂ Ｏ３ 〔式中、Ｍはマグネシウ
ムを除くアルカリ土類金属であり、０＜ｘ≦０．５，０
＜ｙ≦０．５、そして０．９５≦ｂ／ａ＜１又は１＜ｂ
／ａ≦１．０５である。〕で表わされ主としてペロブス
カイト構造からなることを特徴とするランタンクロマイ
ト系複合酸化物。Claim 2: General formula (La1-x Mx) a (
Cr1-y Fe)b O3 [In the formula, M is an alkaline earth metal excluding magnesium, and 0<x≦0.5,0
<y≦0.5 and 0.95≦b/a<1 or 1<b
/a≦1.05. ] A lanthanum chromite-based composite oxide characterized by being mainly composed of a perovskite structure.
イト系複合酸化物からなる高温導電性材料。3. A high temperature conductive material comprising the lanthanum chromite complex oxide according to claim 1 or 2.
イト系複合酸化物からなるセパレータを用いた高温型燃
料電池。4. A high-temperature fuel cell using a separator made of the lanthanum chromite complex oxide according to claim 1 or 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3067465A JPH04214069A (en) | 1990-03-30 | 1991-03-30 | Lanthanum chromite-based multiple oxide and its application |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2-81260 | 1990-03-30 | ||
| JP8126090 | 1990-03-30 | ||
| JP3067465A JPH04214069A (en) | 1990-03-30 | 1991-03-30 | Lanthanum chromite-based multiple oxide and its application |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04214069A true JPH04214069A (en) | 1992-08-05 |
Family
ID=26408683
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3067465A Pending JPH04214069A (en) | 1990-03-30 | 1991-03-30 | Lanthanum chromite-based multiple oxide and its application |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04214069A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6248465B1 (en) | 1998-05-13 | 2001-06-19 | Murata Manufacturing Co., Ltd. | Complex oxide ceramic sintered body and solid-electrolyte fuel cell comprising the same |
| JP2017065991A (en) * | 2015-09-30 | 2017-04-06 | 大日精化工業株式会社 | Perovskite-based black powder, method for producing the same, and resin composition using the same |
-
1991
- 1991-03-30 JP JP3067465A patent/JPH04214069A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6248465B1 (en) | 1998-05-13 | 2001-06-19 | Murata Manufacturing Co., Ltd. | Complex oxide ceramic sintered body and solid-electrolyte fuel cell comprising the same |
| JP2017065991A (en) * | 2015-09-30 | 2017-04-06 | 大日精化工業株式会社 | Perovskite-based black powder, method for producing the same, and resin composition using the same |
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