JP2612545B2 - Heat-resistant conductive ceramics - Google Patents
Heat-resistant conductive ceramicsInfo
- Publication number
- JP2612545B2 JP2612545B2 JP6190214A JP19021494A JP2612545B2 JP 2612545 B2 JP2612545 B2 JP 2612545B2 JP 6190214 A JP6190214 A JP 6190214A JP 19021494 A JP19021494 A JP 19021494A JP 2612545 B2 JP2612545 B2 JP 2612545B2
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- JP
- Japan
- Prior art keywords
- sintered body
- partial pressure
- oxygen partial
- conductivity
- heat
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Compositions Of Oxide Ceramics (AREA)
- Conductive Materials (AREA)
- Fuel Cell (AREA)
Description
【０００１】[0001]
【産業上の利用分野】本発明は、８００℃以上の大気中
及び加湿水素中などの低酸素分圧下において安定であ
り、高耐熱性と高導電性を有する新規な耐熱導電性セラ
ミックスに関する。このような新規な耐熱導電性セラミ
ックスは、固体電解質型燃料電池部材、発熱体素子、耐
熱電極などの高温導電性材料として有用である。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel heat-resistant conductive ceramic which is stable under a low oxygen partial pressure such as in the atmosphere of 800 ° C. or higher and in humidified hydrogen and has high heat resistance and high conductivity. Such a novel heat-resistant conductive ceramic is useful as a high-temperature conductive material such as a solid oxide fuel cell member, a heating element, and a heat-resistant electrode.
【０００２】[0002]
【従来の技術】化学式ＬａＣｒＯ3 で表されるセラミッ
クスのＬａの一部をＡ（ＡはＣａ、Ｓｒなど）で固溶置
換し、同時にＣｒの一部をＭ（ＭはＣｏ、Ｎｉなど）で
固溶置換した化学式Ｌａ1-x Ａx Ｃｒ1-y Ｍy Ｏ3 によ
り表されるセラミックスは導電性が高く、且つ焼結しや
すいペロブスカイト型結晶構造を有する酸化物として提
案されている。2. Description of the Related Art A part of La in ceramics represented by the chemical formula LaCrO 3 is solid-solution-substituted by A (A is Ca, Sr, etc.), and a part of Cr is simultaneously replaced by M (M is Co, Ni, etc.). ceramics represented by solid solution obtained by substituting the formula La 1-x a x Cr 1 -y M y O 3 is highly conductive, have been proposed as and oxides having a sintering tends perovskite crystal structure.
【０００３】しかしながら、このようなＬａ1-x Ａx Ｃ
ｒ1-y Ｍy Ｏ3 で表される組成の焼結体は、緻密質で高
導電性ではあるが、高温加湿水素雰囲気中などの低酸素
分圧下で使用する場合には、体積膨張が大きいために焼
結体内部に微少なクラック等が発生し易く、機械的特性
が低下するという欠点がある。また、かかる焼結体を固
体電解質型燃料電池のセパレータとして使用する場合に
は、焼結体の両側において酸素分圧が大きく異なるた
め、低酸素分圧側では上述したような表面付近での体積
膨張による伸びや機械的特性の低下のためにセパレータ
に反りや割れが生じ易く、セルの破損や性能の低下につ
ながる等の問題点がある。従って、上記組成の焼結体
は、各種の高温雰囲気中において、安定した状態で長時
間使用可能な実用的材料とは言い難い状態である。However, such a La 1-x A x C
sintered body having a composition represented by r 1-y M y O 3, albeit with high conductivity in dense, when used in low oxygen partial pressure, such as in a high-temperature humidified hydrogen atmosphere, the volume expansion Due to the large size, minute cracks and the like are easily generated inside the sintered body, and there is a disadvantage that mechanical properties are deteriorated. Further, when such a sintered body is used as a separator of a solid oxide fuel cell, since the oxygen partial pressure is greatly different on both sides of the sintered body, the volume expansion near the surface as described above on the low oxygen partial pressure side. The separator is liable to warp or crack due to elongation or a decrease in mechanical properties due to cracking, resulting in problems such as breakage of cells and deterioration of performance. Therefore, the sintered body having the above composition is hardly a practical material that can be used for a long time in a stable state in various high-temperature atmospheres.
【０００４】また、上記化学式におけるｘの値を小さく
することによって、低酸素分圧下における焼結体の安定
性を改善できることも明らかになりつつあるが、これに
よっても長期間使用した場合の安定性については、なお
十分とはいい難い状態である。[0004] It has also become clear that the stability of the sintered body under a low oxygen partial pressure can be improved by reducing the value of x in the above chemical formula. Is not yet enough.
【０００５】[0005]
【発明が解決しようとする課題】本発明の主な目的は、
高温の大気中や加湿水素中などの低酸素分圧下におい
て、従来知られている各種の材料と比べて安定性に優
れ、しかも長期間安定性の低下することのない耐熱導電
性材料を提供することにある。SUMMARY OF THE INVENTION The main object of the present invention is to:
To provide a heat-resistant conductive material that is superior in stability to various conventionally known materials under low oxygen partial pressure, such as in a high-temperature atmosphere or humidified hydrogen, and does not decrease in stability for a long time. It is in.
【０００６】[0006]
【課題を解決するための手段】本発明者は、上記のよう
な従来技術の問題点に鑑みて、鋭意研究を重ねた結果、
化学式ＬａＣｒＯ3 で表されるセラミックスのＬａの一
部をＡで固溶置換し、同時にＣｒの一部をＭで固溶置換
した化学式Ｌａ1-x Ａx Ｃｒ1-y Ｍy Ｏ3 で表わされる
セラミックスにおいて、更に、Ｃｒの一部をＡｌ及びＭ
ｇの少なくとも一種で固溶置換する場合には、低酸素分
圧下における安定性がより改善されたものとなり、この
様な焼結体における固溶置換すべき各成分の種類及びそ
の量を特定範囲に制御すると共に、焼結体のかさ密度、
伸び率、導電率及び曲げ強さを所定範囲とすることによ
って、高温の大気中や加湿水素中などの低酸素分圧下で
の導電性と強度を兼ね備え、しかも耐久性が大幅に改善
された焼結体を得ることができることを見出し、ここに
本発明を完成するに至った。Means for Solving the Problems The present inventor has conducted intensive studies in view of the above-mentioned problems of the prior art.
A part of La of ceramics represented by the chemical formula LaCrO 3 is solid-solution-substituted with A, and a part of Cr is solid-solution-substituted with M, and is represented by a chemical formula La 1-x A x Cr 1- y My O 3 . In some ceramics, a part of Cr is changed to Al and M
In the case of performing solid solution substitution with at least one of g, the stability under low oxygen partial pressure is further improved, and the type and amount of each component to be subjected to solid solution substitution in such a sintered body are specified. And the bulk density of the sintered body,
By setting the elongation, conductivity, and bending strength within the specified ranges, the sintering has both conductivity and strength under a low oxygen partial pressure such as in a high-temperature atmosphere or humidified hydrogen, and has greatly improved durability. The present inventors have found that a union can be obtained, and have completed the present invention.
【０００７】即ち、本発明は下記の耐熱導電性セラミッ
クスを提供するものである。That is, the present invention provides the following heat-resistant conductive ceramics.
【０００８】１.（１）化学式 ( Ｌａ1-x Ａx ）a (
Ｃｒ1-y-z Ｍy Ｂz ）b Ｏ3 （式中、ＡはＣａ及びＳｒ
の少なくとも一種を示し、０＜ｘ≦０．２であり、Ｍは
Ｃｏ及びＮｉの少なくとも一種を示し、０＜ｙ≦０．１
であり、ＢはＡｌ及びＭｇの少なくとも一種を示し、０
＜ｚ≦０．１であり、０＜ｙ＋ｚ≦０．１８、０．９５
≦ａ／ｂ≦１．０２である）で表されるペロブスカイト
型結晶構造を有する焼結体であり、（２）焼結体のかさ
密度が理論密度の９２％以上、（３）１０００℃での酸
素分圧が１０-16 atm となる加湿水素雰囲気中１０００
℃で１０時間熱処理した後の室温での焼結体の伸び率が
０. １５％以下、（４）１０００℃での酸素分圧が１０
-16 atm となる加湿水素雰囲気中１０００℃における導
電率が０. ５Ｓ／ｃｍ以上、（５）室温曲げ強さが１０
ｋｇｆ／ｍｍ2 以上であり、且つ１０００℃での酸素分
圧が１０-16 atm となる加湿水素雰囲気中１０００℃で
１０時間熱処理した後の焼結体の室温曲げ強さが８ｋｇ
ｆ／ｍｍ2 以上であることを特徴とする耐熱導電性セラ
ミックス。1. (1) Chemical formula (La 1-x A x ) a (
Cr 1-yz M y B z ) b O 3 ( wherein, A is Ca and Sr
0 <x ≦ 0.2, M represents at least one of Co and Ni, and 0 <y ≦ 0.1
And B represents at least one of Al and Mg, and 0
<Z ≦ 0.1, 0 <y + z ≦ 0.18, 0.95
≦ a / b ≦ 1.02), wherein (2) the bulk density of the sintered body is at least 92% of the theoretical density, and (3) at 1000 ° C. 1000 in a humidified hydrogen atmosphere where the oxygen partial pressure is 10 -16 atm
The elongation percentage of the sintered body at room temperature after heat treatment at 10 ° C. for 10 hours is 0.15% or less, and (4) the oxygen partial pressure at 1000 ° C. is 10%.
The conductivity at 1000 ° C. in a humidified hydrogen atmosphere at -16 atm is 0.5 S / cm or more, and (5) the room temperature bending strength is 10
kgf / mm 2 or more, and the sintered body has a room temperature bending strength of 8 kg after heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere in which the oxygen partial pressure at 1000 ° C. is 10 −16 atm.
A heat-resistant conductive ceramic having a f / mm 2 or more.
【０００９】２．化学式( Ｌａ1-x Ａx ）a ( Ｃｒ
1-y-z Ｍy Ｂz ）b Ｏ3 で表される焼結体のＬａの５０
モル％以下をイットリウム及び原子番号５８から７１の
希土類元素の少なくとも一種で置換したものである請求
項１に記載の耐熱導電性セラミックス。[0009] 2. Chemical formula (La 1-x A x ) a (Cr
1-yz M y B z) b O 3 50 of La sintered body represented by
The heat-resistant conductive ceramic according to claim 1, wherein less than mol% is replaced with yttrium and at least one of rare earth elements having atomic numbers 58 to 71.
【００１０】以下に、本発明の耐熱導電性セラミックス
が満足すべき上記（１）〜（５）の各要件について詳細
に説明する。Hereinafter, the requirements (1) to (5) that the heat-resistant conductive ceramic of the present invention should satisfy will be described in detail.
【００１１】（１）化学式 ( Ｌａ1-x Ａx ）a ( Ｃｒ
1-y-z Ｍy Ｂz ）b Ｏ3 （式中、ＡはＣａ及びＳｒの少
なくとも一種を示し、０＜ｘ≦０．２であり、ＭはＣｏ
及びＮｉの少なくとも一種を示し、０＜ｙ≦０．１であ
り、ＢはＡｌ及びＭｇの少なくとも一種を示し、０＜ｚ
≦０．１であり、０＜ｙ＋ｚ≦０．１８、０．９５≦ａ
／ｂ≦１．０２である）で表されるペロブスカイト型結
晶構造を有する焼結体であること。(1) Chemical formula (La 1-x A x ) a (Cr
1-yz M y B z) b O 3 ( in the formula, A represents at least one of Ca and Sr, an 0 <x ≦ 0.2, M is Co
And at least one of Ni and 0 <y ≦ 0.1, B represents at least one of Al and Mg, and 0 <z
≦ 0.1, 0 <y + z ≦ 0.18, 0.95 ≦ a
/B≦1.02) that is a sintered body having a perovskite crystal structure.
【００１２】本発明の耐熱導電性セラミックスは、Ｌａ
ＣｒＯ3 を基本構造とし、Ｌａの一部をＣａ及びＳｒ
（以下この両者をまとめてＡと記すことがある）の少な
くとも一種で固溶置換し、Ｃｒの一部をＣｏ及びＮｉ
（以下この両者をまとめてＭと記すことがある）の少な
くとも一種で固溶置換したものであり、ペロブスカイト
型結晶構造を有するものであることが必要である。この
様なセラミックスでは、３価のＬａの一部を２価のＡで
固溶置換することによって生じる正の電荷の不足分を、
Ｃｒの３価から一部４価への原子価移動により補う構造
となり、その結果、隣接するＣｒイオンの３価と４価と
の間に電子の速やかな移動が生じて導電性が大幅に向上
する。また、Ａの置換量が多くなると、導電性とともに
焼結性も大幅に向上する。また、Ｃｒの一部をＭで固溶
置換することも、導電性及び焼結性を向上させる効果が
ある。The heat-resistant conductive ceramic of the present invention is La
CrO 3 as a basic structure, La is partially Ca and Sr
(Hereinafter, both of these may be collectively referred to as A).
(Hereinafter, both of these may be collectively referred to as M). At least one of them is a solid solution-substituted one and must have a perovskite crystal structure. In such ceramics, the shortage of positive charge caused by solid solution replacement of a part of trivalent La with divalent A is
The structure is compensated by the valence transfer of Cr from trivalent to partially tetravalent, and as a result, electrons move quickly between trivalent and tetravalent of adjacent Cr ions, and the conductivity is greatly improved. I do. Further, when the substitution amount of A increases, the sinterability as well as the conductivity is greatly improved. Replacing part of Cr with a solid solution with M also has the effect of improving conductivity and sinterability.
【００１３】一方、ＡおよびＭの固溶置換量が増加すれ
ば、上述したように焼結性及び導電性は向上するもの
の、熱膨張係数が大きくなり、ジルコニアを電解質とし
た固体電解質型燃料電池のセパレータに使用した場合等
には、還元雰囲気側の体積膨張によるセパレータの反り
の発生とともに、ジルコニア電解質との熱膨張係数の差
が大きくなり、セルの破損や性能低下を引き起こすこと
がある。かかる現象は、（ＬａＡ）（ＣｒＭ) Ｏ3 焼結
体では、高温の低酸素分圧下にさらされた場合には、焼
結体から酸素イオンが系外に抜けでた後に酸素空孔子が
生成し、酸素空孔子は陽イオンとの間に引力作用が働か
ないので、酸素空孔子数が増えすぎると、陽イオンと酸
素イオンの間に働く引力作用の総和が小さくなり、逆に
異種の陽イオン間の斥力作用が強く現れ、結晶格子間の
拡張が生じて、焼結体が伸張し、このことが低酸素分圧
下での安定性の低下の一因となって生じるものと推定さ
れる。On the other hand, when the solid solution substitution amount of A and M is increased, the sinterability and conductivity are improved as described above, but the thermal expansion coefficient is increased, and the solid electrolyte fuel cell using zirconia as the electrolyte is used. In the case where the separator is used, the difference in thermal expansion coefficient between the separator and the zirconia electrolyte increases with the occurrence of warpage of the separator due to volume expansion on the reducing atmosphere side, which may cause cell breakage or performance deterioration. This phenomenon is caused by the fact that, when the (LaA) (CrM) O 3 sintered body is exposed to a high temperature and a low oxygen partial pressure, oxygen vacancies are generated after oxygen ions escape from the sintered body to the outside of the system. However, since oxygen vacancies do not have an attractive effect with cations, if the number of oxygen vacancies increases too much, the total attractive force acting between the cations and oxygen ions decreases, and conversely, different types of positive ions It is presumed that the repulsive action between ions appears strongly and the crystal lattice expands, and the sintered body expands, which contributes to the decrease in stability under low oxygen partial pressure. .
【００１４】したがって、本発明の焼結体においては、
焼結性及び導電性の向上と、高温の低酸素分圧下におけ
る安定性の両方を考慮して、上記化学式の中のＡの固溶
置換量であるｘ値を、モル比で０＜ｘ≦０．２、好まし
くは０＜ｘ≦０．１６とし、上記化学式の中のＭの固溶
置換量であるｙ値を、モル比で０＜ｙ≦０．１、好まし
くは０＜ｙ≦０．０６とする。ｘ及びｙの値がこの範囲
を上回ると、上述したように還元時の体積膨脹や熱膨脹
係数の増加が生じ易くなって、ジルコニアを電解質とし
た固体電解質型燃料電池のセパレーターに使用した場合
等には、セルの破損や性能低下を引き起こすので好まし
くない。Therefore, in the sintered body of the present invention,
In consideration of both improvement in sinterability and conductivity and stability under high-temperature low oxygen partial pressure, the value x, which is the amount of solid solution substitution of A in the above chemical formula, is expressed as a molar ratio of 0 <x ≦ 0.2, preferably 0 <x ≦ 0.16, and the y value, which is the amount of solid solution substitution of M in the above chemical formula, is expressed as a molar ratio of 0 <y ≦ 0.1, preferably 0 <y ≦ 0. .06. When the values of x and y exceed this range, the volume expansion and the thermal expansion coefficient at the time of reduction tend to increase as described above, and when used as a separator of a solid oxide fuel cell using zirconia as an electrolyte, etc. Is not preferred because it causes cell breakage and performance degradation.
【００１５】更に、本発明では、Ｌａの一部をＡで固溶
置換し、Ｃｒの一部をＭで固溶置換することに加えて、
Ｃｒの一部をＡｌ及びＭｇ（以下、この両者をまとめて
Ｂと記すことがある）の少なくとも一種で固溶置換する
ことが必要である。この様に、Ｃｒの一部をＢで固溶置
換することによって、Ｌａの一部をＡで固溶置換し、Ｃ
ｒの一部をＭで固溶置換しただけの場合と比べて、高温
の低酸素分圧下における安定性をより長期間持続するこ
とが可能となる。上記化学式におけるＢの固溶置換量で
あるｚ値は、モル比で０＜ｚ≦０．１、好ましくは０＜
ｚ≦０．０８とし、ＭとＢによるＣｒの固溶置換量の合
計値（ｙ＋ｚ）の許容範囲は、モル比で０＜ｙ＋ｚ≦
０．１８、好ましくは０＜ｙ＋ｚ≦０．１０とすること
が必要である。ｚ及びｙ＋ｚの値がこの範囲を上回る
と、還元性雰囲気中での機械的特性や導電性等の安定性
が低下するので好ましくない。Further, in the present invention, in addition to the solid solution substitution of a part of La with A and the solid solution substitution of a part of Cr with M,
It is necessary to replace a part of Cr with at least one of Al and Mg (hereinafter, both may be collectively referred to as B) in solid solution. Thus, by partially dissolving Cr with B, a part of La is solid-displaced with A, and C is partially dissolved.
Compared to the case where only a part of r is solid-solution-substituted with M, stability under a high-temperature and low oxygen partial pressure can be maintained for a longer period of time. The z value, which is the amount of solid solution substitution of B in the above chemical formula, is 0 <z ≦ 0.1, preferably 0 <in molar ratio.
z ≦ 0.08, and the allowable range of the total value (y + z) of the solid solution substitution amounts of Cr by M and B is 0 <y + z ≦
0.18, preferably 0 <y + z ≦ 0.10. If the values of z and y + z exceed this range, the stability in mechanical properties and conductivity in a reducing atmosphere is undesirably reduced.
【００１６】また、本発明の焼結体におけるＬａＣｒＯ
3 のＬａサイトとＣｒサイトの比であるａ／ｂの許容範
囲は、０．９５≦ａ／ｂ≦１．０２であり、好ましくは
１である。ａ／ｂ値が上記範囲をはずれると、焼結性に
影響したり、ＬａＣｒＯ3 以外の結晶相が析出するので
好ましくなく、特に、ａ／ｂが１．０２を上回る場合に
は、緻密な焼結体が得られたとしても、粒界に偏析する
Ｌａ2 Ｏ3 のために、大気中においても非常に脆くなる
ので好ましくない。In the sintered compact of the present invention, LaCrO
Tolerance of a ratio of 3 La site and Cr site a / b is 0.95 ≦ a / b ≦ 1.02, preferably 1. If the a / b value is out of the above range, the sinterability is affected and a crystal phase other than LaCrO 3 is precipitated, which is not preferable. Even if a compact is obtained, it is not preferable because La 2 O 3 segregates at the grain boundary and becomes very brittle even in the air.
【００１７】また、上記化学式( Ｌａ1-x Ａx ）a ( Ｃ
ｒ1-y-z Ｍy Ｂz ）b Ｏ3 において、Ｌａの５０モル％
以下をイットリウム及び原子番号５８から７１の希土類
元素の少なくとも一種（複数元素でも可）で固溶置換し
ても良く、このような組成の焼結体も優れた焼結性を示
し、耐熱性と導電性の著しい低下も認められない。元素
源としては、酸化物、水酸化物、炭酸塩、硝酸塩あるい
は金属アルコキシドなどのセラミックス製造に通常使用
される化合物が使用され、化合物の種類やその形態は、
特に限定されない。Further, the above chemical formula (La 1-x A x ) a (C
In r 1-yz M y B z ) b O 3, 50 of La mole%
The following may be replaced by solid solution with yttrium and at least one (or a plurality of elements) of rare earth elements having atomic numbers 58 to 71, and a sintered body having such a composition also exhibits excellent sinterability, No significant decrease in conductivity is observed. As the element source, compounds commonly used in the production of ceramics such as oxides, hydroxides, carbonates, nitrates or metal alkoxides are used.
There is no particular limitation.
【００１８】（２）焼結体のかさ密度は理論密度の９２
％以上とする。(2) The bulk density of the sintered body is 92% of the theoretical density.
% Or more.
【００１９】かさ密度が理論密度の９２％未満では、気
孔量の増加により、導電性、気密性、機械的強度等が著
しく低下する。従って、かさ密度は理論密度の９２％以
上であることが必要であり、９３％以上であることが好
ましく、固体電解質型燃料電池のセパレータのように、
使用時に材料の片側が高温の空気等の高酸素分圧下にさ
らされ、他の高温の水素等の低酸素分圧下にさらされる
場合には、水素ガスに対する気密性を維持するために、
かさ密度は理論密度の９４％以上であることが更に望ま
しい。When the bulk density is less than 92% of the theoretical density, the conductivity, airtightness, mechanical strength, etc. are significantly reduced due to an increase in the amount of pores. Therefore, the bulk density needs to be 92% or more of the theoretical density, and preferably 93% or more. As in the case of a solid oxide fuel cell separator,
When one side of the material is exposed to a high oxygen partial pressure such as high-temperature air during use and is exposed to a low oxygen partial pressure such as another high-temperature hydrogen, in order to maintain airtightness against hydrogen gas,
More preferably, the bulk density is at least 94% of the theoretical density.
【００２０】（３）１０００℃での酸素分圧が１０-16
atm となる加湿水素雰囲気中１０００℃で１０時間熱処
理した後の室温での焼結体の伸び率は０. １５％以下と
する。(3) Oxygen partial pressure at 1000 ° C. is 10 -16
The elongation percentage of the sintered body at room temperature after heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere atm is set to 0.15% or less.
【００２１】本焼結体を例えば、固体電解質型燃料電池
のセパレータのように焼結体の両面を１０００℃の異な
る雰囲気（片側は水素ガス、他面は空気）にさらして使
用する場合、前述したように低酸素分圧となる水素ガス
側では結晶格子間の拡張により焼結体が伸張するため、
焼結体に変形が生じる可能性がある。この場合において
も安定に使用するためには、高温における焼結体の機械
的強度、弾性率、クリープ強度等から、１０００℃での
酸素分圧が１０-16 atm となる加湿水素雰囲気中１００
０℃で１０時間熱処理した後の室温での焼結体の伸び率
が０. １５％以下であることが必要である。この伸び率
が０. １５％を上回ると、焼結体にマイクロクラックが
生じ易くなること等により、高温の低酸素分圧下での強
度が低下したり、例えば上記燃料電池の場合のように、
加重が加わった場合に、変形が生じたり、機械的強度が
低下するなどして、、焼結体が壊れ易くなり、耐久性に
劣るものとなる。For example, when the present sintered body is used by exposing both surfaces of the sintered body to different atmospheres of 1000 ° C. (one side is hydrogen gas and the other side is air) like a solid oxide fuel cell separator, for example, As described above, on the hydrogen gas side where the oxygen partial pressure is low, the sintered body expands due to expansion between crystal lattices.
The sintered body may be deformed. In this case, in order to use the sintered body in a stable manner, it is necessary to use a humidified hydrogen atmosphere in which the oxygen partial pressure at 1000 ° C. becomes 10 −16 atm based on the mechanical strength, elastic modulus, creep strength and the like of the sintered body at a high temperature.
It is necessary that the elongation of the sintered body at room temperature after heat treatment at 0 ° C. for 10 hours is 0.15% or less. If the elongation is more than 0.15%, microcracks are likely to occur in the sintered body, and the strength at high temperature and low oxygen partial pressure is reduced. For example, as in the case of the fuel cell described above,
When a load is applied, the sintered body is easily broken due to deformation or a decrease in mechanical strength, resulting in poor durability.
【００２２】この伸び率を０. １５％以下とするために
は、前記化学式のＡ、Ｍ及びＢの種類、ｘ、ｙ、ｚ及び
ｙ＋ｚのモル量を規定の範囲内にするとともに、焼結体
に含有される６価Ｃｒ量が１. ５重量％以下であること
が望ましい。In order to reduce the elongation to 0.15% or less, the types of A, M and B in the above-mentioned chemical formula, the molar amounts of x, y, z and y + z are set within the specified ranges, and the sintering is performed. It is desirable that the amount of hexavalent Cr contained in the body is 1.5% by weight or less.
【００２３】尚、伸び率は、熱処理前の室温での試料の
長さＬ0 と、１０００℃での酸素分圧が１０-16 atm と
なる加湿水素雰囲気中１０００℃で１０時間熱処理した
後の室温での試料の長さＬから次式により求めた値であ
る。The elongation percentage was determined by measuring the length L 0 of the sample at room temperature before heat treatment and the heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere in which the oxygen partial pressure at 1000 ° C. was 10 −16 atm. This is a value obtained by the following equation from the length L of the sample at room temperature.
【００２４】 伸び率（％）＝｛（ＬーＬ0 ）／Ｌ0 ｝×１００ （４）１０００℃での酸素分圧が１０-16 atm となる加
湿水素雰囲気中１０００℃における導電率は０. ５Ｓ／
ｃｍ以上とする。Elongation (%) = {(L−L 0 ) / L 0 } × 100 (4) The conductivity at 1000 ° C. in a humidified hydrogen atmosphere where the oxygen partial pressure at 1000 ° C. is 10 −16 atm is 0. . 5S /
cm or more.
【００２５】本セラミックスが固体電解質型燃料電池の
セパレータとして使用される場合には、低酸素分圧下に
さらされる側の導電率は、主として４価のＣｒの還元に
より減少するが、低酸素分圧下において良好な導電率を
維持するためには、１０００℃での酸素分圧が１０-16
atm となる加湿水素雰囲気中１０００℃における導電率
が０. ５Ｓ／ｃｍ以上であることが必要であり、１Ｓ／
ｃｍ以上であることが好ましい。また、大気中１０００
℃における導電率は、５Ｓ／ｃｍ以上であることが好ま
しい。When the present ceramics is used as a separator of a solid oxide fuel cell, the conductivity on the side exposed to a low oxygen partial pressure is reduced mainly by reduction of tetravalent Cr, In order to maintain good electrical conductivity, the oxygen partial pressure at 1000 ° C. is 10 −16.
It is necessary that the conductivity at 1000 ° C. in a humidified hydrogen atmosphere at which the pressure is atm is 0.5 S / cm or more.
cm or more. 1000 in the atmosphere
The conductivity at ° C. is preferably 5 S / cm or more.
【００２６】（５）室温曲げ強さが１０ｋｇｆ／ｍｍ2
以上であり、且つ１０００℃での酸素分圧が １０-16
atm となる加湿水素雰囲気中１０００℃で１０時間熱処
理した後の焼結体の室温曲げ強さが８ｋｇｆ／ｍｍ2 以
上であること。(5) Room temperature flexural strength of 10 kgf / mm 2
And the oxygen partial pressure at 1000 ° C. is 10 −16
The sintered body has a room temperature bending strength of 8 kgf / mm 2 or more after heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere atm.
【００２７】本発明のセラミックスは、例えば、固体電
解質型燃料電池部材、発熱体素子、耐熱電極などの高温
導電性材料として使用されるものであり、十分な強度を
有するために焼結体の室温曲げ強さが１０ｋｇｆ／ｍｍ
2 以上であることが必要であり、１２ｋｇｆ／ｍｍ2 以
上であることが好ましい。また、この焼結体を、固体電
解質型燃料電池のセパレータのように使用時に材料が高
温の加湿水素等の低酸素分圧下にさらされるような用途
に用いる場合には、この雰囲気下でも十分な強度を有す
る必要があり、この焼結体を１０００℃での酸素分圧が
１０-16 atm となる加湿水素雰囲気中１０００℃で１０
時間熱処理した後の室温曲げ強さは８ｋｇｆ／ｍｍ2 以
上であることが必要であり、１０ｋｇｆ／ｍｍ2 以上で
あることが好ましい。The ceramic of the present invention is used as a high-temperature conductive material such as a solid oxide fuel cell member, a heating element, a heat-resistant electrode, and the like. Flexural strength is 10kgf / mm
Must be at least two, it is preferably 12 kgf / mm 2 or more. Further, when the sintered body is used for applications in which the material is exposed to a low oxygen partial pressure such as high-temperature humidified hydrogen at the time of use, such as a separator of a solid oxide fuel cell, even under this atmosphere, it is sufficient. The sintered body must have strength, and the sintered body is heated at 1000 ° C. in a humidified hydrogen atmosphere at an oxygen partial pressure of 10 −16 atm.
The room temperature flexural strength after heat treatment for a period of time must be 8 kgf / mm 2 or more, and preferably 10 kgf / mm 2 or more.
【００２８】尚、還元処理後の室温曲げ強さは、前述の
通り、還元処理後の焼結体の伸び率にも依存しており、
還元処理後も十分な強度を保つためには、還元処理後の
焼結体の伸び率を前記規定値の範囲内にすると共に、焼
結体に含有される６価Ｃｒ量が１. ５重量％以下である
ことが望ましい。また、同様に還元処理後の室温曲げ強
さを上記範囲とするためには、焼結体の平均結晶粒径が
３０μｍ以下であることが好ましい。As described above, the room temperature bending strength after the reduction treatment also depends on the elongation percentage of the sintered body after the reduction treatment.
In order to maintain a sufficient strength even after the reduction treatment, the elongation of the sintered body after the reduction treatment is set within the range of the specified value, and the amount of hexavalent Cr contained in the sintered body is 1.5 wt. % Is desirable. Similarly, in order to maintain the room temperature bending strength after the reduction treatment in the above range, the average crystal grain size of the sintered body is preferably 30 μm or less.
【００２９】本発明による焼結体は、通常以下のように
して製造される。The sintered body according to the present invention is usually produced as follows.
【００３０】先ず、焼結体を構成する各成分の原料（Ｌ
ａ源、Ａ源、Ｃｒ源、Ｍ源及びＢ源）を所定の割合に配
合し、均一に混合、分散して、粉末混合物を得る。各原
料としては、酸化物、水酸化物、炭酸塩、硝酸塩あるい
は金属アルコキシドなどのセラミックス製造に通常使用
される化合物を使用できる。粉末の粒度は、特に限定さ
れないが、通常は１０μｍ以下程度とすることが望まし
い。混合は、粉末の湿式混合叉は乾式混合のいずれの方
法によっても良く、また、各元素を含む水溶液などの混
合でも良い。尚、湿式混合の場合は有機溶媒を使用する
ことが好ましく、水を使用する場合にはアルカリ成分や
ＳｉＯ2 分などの含有量が、それぞれ０. ２重量％を上
回らないようにイオン交換水、若しくは蒸留水を使用す
ることが望ましい。First, the raw materials (L
a source, A source, Cr source, M source and B source) are blended in a predetermined ratio, and uniformly mixed and dispersed to obtain a powder mixture. As each raw material, compounds commonly used in the production of ceramics such as oxides, hydroxides, carbonates, nitrates and metal alkoxides can be used. Although the particle size of the powder is not particularly limited, it is usually desirable that the particle size be about 10 μm or less. The mixing may be performed by either wet mixing or dry mixing of powders, or may be performed by mixing an aqueous solution containing each element. In the case of wet mixing, it is preferable to use an organic solvent. In the case of using water, ion-exchanged water or water is used so that the content of each of the alkali component and the SiO 2 component does not exceed 0.2% by weight. Alternatively, it is desirable to use distilled water.
【００３１】次いで、上記で得られた粉末混合物を、そ
の７０％以上がペロブスカイト型結晶構造となる温度以
上で熱処理し、合成粉末とする。合成温度は通常８００
〜１４００℃程度の範囲にあり、より好ましくは９００
〜１３５０℃程度の範囲にある。合成時間は合成温度と
も関係するが、通常０. ５〜１０時間程度である。合成
雰囲気は大気中など酸素含有雰囲気が好ましい。更にこ
の合成物を粉砕後、上記の熱処理を数回繰り返して組成
の均一化を図ることが望ましい。Next, the above-obtained powder mixture is heat-treated at a temperature of 70% or more at which a perovskite-type crystal structure is obtained to obtain a synthetic powder. The synthesis temperature is usually 800
１1400 ° C., more preferably 900 ° C.
範 囲 1350 ° C. Although the synthesis time is related to the synthesis temperature, it is usually about 0.5 to 10 hours. The synthesis atmosphere is preferably an oxygen-containing atmosphere such as the air. Further, after pulverizing this composite, it is desirable to repeat the above heat treatment several times to make the composition uniform.
【００３２】その後、上記で得られた合成粉末を粉砕、
分散する。この工程は前記混合処理と同様に有機溶媒の
存在下で行うことが好ましいが、水の存在下で行う場合
には、アルカリ成分やＳｉＯ2 分などの含有量が、上記
範囲を上回ることがないように、イオン交換水、若しく
は蒸留水を使用することが望ましい。粉砕、分散後の合
成粉末は、平均粒径が３μｍ以下で比表面積が２ｍ2 ／
ｇ以上であることが好ましく、平均粒径が１μｍ以下で
比表面積が３ｍ2 ／ｇ以上であることがより好ましい。
この粉砕により、焼結体中組成と構成粒子径の均一化が
実現できる。Then, the synthetic powder obtained above is pulverized,
Spread. This step is preferably performed in the presence of an organic solvent as in the case of the above-mentioned mixing treatment, but when performed in the presence of water, the content of an alkali component or SiO 2 content does not exceed the above range. Thus, it is desirable to use ion-exchanged water or distilled water. The pulverized and dispersed synthetic powder has an average particle size of 3 μm or less and a specific surface area of 2 m 2 /
g or more, more preferably an average particle size of 1 μm or less and a specific surface area of 3 m 2 / g or more.
By this pulverization, the composition in the sintered body and the particle diameter of the constituent particles can be made uniform.
【００３３】次いで、所定の粒度に粉砕された粉末をプ
レス成形、ＣＩＰ成形、鋳込み成形、テープ成形、押し
出し成形、ホットプレス成形等のセラミックス成形の常
法により成形する。この際、アクリル系など公知の成形
助剤を適当量添加しても良いことは言うまでもない。Next, the powder pulverized to a predetermined particle size is molded by a conventional method of ceramic molding such as press molding, CIP molding, casting molding, tape molding, extrusion molding, and hot press molding. At this time, it goes without saying that an appropriate amount of a known molding aid such as an acrylic resin may be added.
【００３４】続いて、得られた成形体を焼成する。焼成
雰囲気は減圧、常圧及び加圧のいずれであっても良い。
焼成温度は通常１５００〜１９００℃程度の範囲とし、
好ましくは１６００〜１８００℃程度の範囲とする。
尚、具体的な焼成温度、保持時間等は焼結体のかさ密度
などの特性値が要求される範囲となるように適宜設定す
ればよい。Subsequently, the obtained molded body is fired. The firing atmosphere may be any of reduced pressure, normal pressure, and pressure.
The firing temperature is usually in the range of about 1500 to 1900 ° C,
Preferably, it is in the range of about 1600 to 1800 ° C.
The specific firing temperature, holding time, and the like may be appropriately set so that the characteristic values such as the bulk density of the sintered body are within a required range.
【００３５】加圧焼結の場合には、より低温で焼結体を
緻密化させることができる。また、Ａ、Ｍ及びＢ成分が
少ない場合には、焼成温度を高める必要がある。低酸素
分圧下で焼成した焼結体については、導電性が低下して
いるので、この焼結体を大気中１０００℃以上の温度で
熱処理することにより、導電性の向上を図ることが望ま
しい。この処理は必ずしも前記の焼成工程に引き続いて
行う必要はなく、上記の条件を充足する限り、焼結体の
使用過程において行っても良い。In the case of pressure sintering, the sintered body can be densified at a lower temperature. When the A, M and B components are small, it is necessary to raise the firing temperature. Since the conductivity of a sintered body fired under a low oxygen partial pressure is reduced, it is desirable to improve the conductivity by heat-treating the sintered body at a temperature of 1000 ° C. or higher in the atmosphere. This treatment does not necessarily need to be performed subsequent to the above-described firing step, and may be performed in the process of using the sintered body as long as the above conditions are satisfied.
【００３６】[0036]
【発明の効果】本発明によれば、下記のような顕著な効
果が達成できる。According to the present invention, the following remarkable effects can be achieved.
【００３７】（１）焼結体の耐熱性、導電性及びかさ密
度を従来技術では達成できなかった程度まで高めること
ができる。(1) The heat resistance, conductivity and bulk density of the sintered body can be increased to a level that could not be achieved by the prior art.
【００３８】（２）特に高温の低酸素分圧下に長時間さ
らされても強度低下、導電率低下が少ない焼結体が得ら
れ、酸素分圧の異なる条件下で焼結体を使用しても伸び
などの変形が少なく、破壊等が生じず耐久性に優れたも
のとなる。(2) A sintered body having a small decrease in strength and a small decrease in electric conductivity even when exposed to a high temperature and a low oxygen partial pressure for a long time can be obtained. Also, there is little deformation such as elongation, and it is excellent in durability without destruction or the like.
【００３９】（３）本発明による焼結体は、水蒸気が存
在する酸化性あるいは還元性雰囲気においても気密性を
保持し、かつ導電性、機械的強度及び形状安定性を長時
間維持でき、しかもジルコニア電解質と熱膨張係数を近
似させることができるので、固体電解質型燃料電池のセ
パレータやインターコネクター、発熱体素子、耐熱電極
などの実用材料として有用である。(3) The sintered body according to the present invention can maintain airtightness even in an oxidizing or reducing atmosphere in which water vapor is present, and can maintain conductivity, mechanical strength, and shape stability for a long time. Since the thermal expansion coefficient can be approximated to that of the zirconia electrolyte, it is useful as a practical material such as a separator, an interconnector, a heating element, and a heat-resistant electrode of a solid oxide fuel cell.
【００４０】[0040]
【実施例】以下に実施例及び比較例を示し、本発明の特
徴とするところをより詳細に説明する。EXAMPLES Examples and comparative examples will be shown below, and the features of the present invention will be described in more detail.
【００４１】実施例１〜５ 表１に示す各組成式の配合となるように、原料粉末を秤
量、配合し、アルコール存在下で湿式で混合、分散を行
った後、乾燥し、大気中１２７０℃で５時間加熱して、
９５％以上がペロブスカイト型構造に合成された粉末を
得た。尚、原料粉末は、組成式に応じて、純度９９. ５
％以上のＬａ2 Ｏ3 、ＳｒＣＯ3 、ＣａＣＯ3 、Ｃｒ2
Ｏ3 、ＣｏＯ、ＮｉＯ、Ａｌ2 Ｏ3 及びＭｇＯの各酸化
物及び炭酸塩から選択して用いた。得られた合成粉末を
媒体撹拌ミルによりアルコール存在下で１２時間湿式で
粉砕、分散し、平均粒径０. ６μｍのスラリーを得た。
次いで、これに成形助剤を加えた後、スプレードライヤ
ーにより成形用顆粒粉体（平均粒径６０μｍ）を調整し
た。この顆粒粉体を成形圧力３tonf／ｃｍ2 でＣＩＰ成
形し、１２０×１２０×５ｍｍの成形体を得た後、大気
中において、表１に記載の温度で４時間焼成した。得ら
れた焼結体をダイヤモンド砥石により研削加工して、表
面を仕上げた試料について特性を測定した。作製した実
施例１〜５の各試料の組成式と焼成温度を表１に示し、
上記した方法で得られた焼結体について測定した特性を
表２に示す。伸び率は、１０００℃での酸素分圧が１０
-16atm となる加湿水素雰囲気中１０００℃で１０時間
熱処理した後、室温で測定した値であり、導電率は１０
００℃での酸素分圧が１０-16 atm となる加湿水素雰囲
気中１０００℃において測定した値であり、曲げ強さは
１０００℃での酸素分圧が１０-16 atm となる加湿水素
雰囲気中１０００℃で１０時間熱処理を行い、熱処理の
前後において測定した値である。Examples 1 to 5 Raw material powders were weighed and blended so as to have the composition shown in Table 1, mixed and dispersed in the presence of alcohol by a wet method, dried, and dried in air. Heat at ℃ for 5 hours,
95% or more of the powder obtained had a perovskite structure. The raw material powder has a purity of 99.5 according to the composition formula.
% Or more of La 2 O 3 , SrCO 3 , CaCO 3 , Cr 2
It was selected from oxides and carbonates of O 3 , CoO, NiO, Al 2 O 3 and MgO. The obtained synthetic powder was wet-pulverized and dispersed in a medium stirring mill in the presence of alcohol for 12 hours to obtain a slurry having an average particle diameter of 0.6 μm.
Next, after adding a molding aid to the mixture, a granule powder for molding (average particle size: 60 μm) was adjusted by a spray dryer. This granule powder was subjected to CIP molding at a molding pressure of 3 tonf / cm 2 to obtain a molded body of 120 × 120 × 5 mm, and then calcined in the atmosphere at a temperature shown in Table 1 for 4 hours. The obtained sintered body was ground by a diamond grindstone, and the characteristics of a sample whose surface was finished were measured. Table 1 shows the composition formulas and firing temperatures of the manufactured samples of Examples 1 to 5,
Table 2 shows properties measured for the sintered body obtained by the above method. The elongation rate is 10% oxygen partial pressure at 1000 ° C.
The value was measured at room temperature after heat treatment at 1000 ° C for 10 hours in a humidified hydrogen atmosphere of -16 atm.
The bending strength is a value measured at 1000 ° C. in a humidified hydrogen atmosphere where the oxygen partial pressure at 00 ° C. is 10 −16 atm. The bending strength is 1000 in a humidified hydrogen atmosphere where the oxygen partial pressure at 1000 ° C. is 10 −16 atm. This is a value measured before and after heat treatment at 10 ° C. for 10 hours.
【００４２】また、実施例１の焼結体を化学分析した結
果、Ｌａ、Ｓｒ、Ｃａ、Ｃｒ、Ｃｏ、Ｎｉ、Ａｌ及びＭ
ｇ以外の主な含有物は、６価Ｃｒ＝０. ７重量％、Ｓｉ
Ｏ2＝０. １重量％以下、Ｎａ2 Ｏ＝０. １重量％以下
であった。Further, as a result of chemical analysis of the sintered body of Example 1, La, Sr, Ca, Cr, Co, Ni, Al and M
The main components other than g are hexavalent Cr = 0.7% by weight, Si
O 2 = 0.1% by weight or less and Na 2 O = 0.1% by weight or less.
【００４３】実施例６ 実施例２の組成式においてＬａの１８モル％をＮｄに代
えた以外、実施例２と同様の操作を行って本発明の焼結
体を得た。その特性を表２に示す。Example 6 A sintered body of the present invention was obtained in the same manner as in Example 2, except that 18 mol% of La in the composition formula of Example 2 was changed to Nd. The characteristics are shown in Table 2.
【００４４】実施例７ 表１に示す組成式の配合となるように、原料粉末を秤
量、混合、分散し、合成した粉末をアルコール中湿式で
粉砕、分散し、スプレードライヤー時に成形助剤を加え
ない以外は、実施例１〜５と同様にして成形用顆粒粉体
を得た。この顆粒粉体を圧力２５０kgf/ｃｍ2 、温度１
６５０℃にてホットプレス成形し、φ８０×５ｍｍの焼
結体を得た。この焼結体を大気中１２００℃で４時間熱
処理した後、ダイヤモンド砥石により研削加工して、表
面を仕上げた試料について特性を測定した。その結果を
表２に示す。Example 7 Raw material powders were weighed, mixed and dispersed so as to have the composition shown in Table 1, and the synthesized powder was pulverized and dispersed in a wet method in alcohol, and a molding aid was added during spray drying. Except for the absence, granules for molding were obtained in the same manner as in Examples 1 to 5. The granulated powder is subjected to a pressure of 250 kgf / cm 2 and a temperature of 1
Hot press molding was performed at 650 ° C. to obtain a sintered body of φ80 × 5 mm. This sintered body was heat-treated at 1200 ° C. for 4 hours in the air, and then ground by a diamond grindstone to measure the characteristics of the sample whose surface was finished. Table 2 shows the results.
【００４５】比較例１〜４ 表１に示す各組成式の配合となるように、原料粉末を秤
量、配合し、その他は実施例１〜５と同様にして作製し
た焼結体について、研削加工と表面加工を加えた後、特
性を測定した。その結果を表２に示す。Comparative Examples 1 to 4 Raw material powders were weighed and blended so as to have the composition shown in Table 1, and the rest was ground in the same manner as in Examples 1 to 5 for grinding. After applying a surface treatment, the characteristics were measured. Table 2 shows the results.
【００４６】[0046]
【表１】 [Table 1]
【００４７】[0047]
【表２】 [Table 2]
【００４８】上記表２から明らかなように、実施例１〜
７の焼結体は、いずれもかさ密度が高く、伸び率が所定
の範囲内であり、更に導電性、強度に優れたものであっ
た。そして、例えば実施例３の焼結体を固体電解質型燃
料電池のセパレータ（１００×１００×３ｍｍ）として
長時間使用し、昇降温を行ってもジルコニア電解質等に
破損は認められなかった。As apparent from Table 2 above, Examples 1 to
Each of the sintered bodies of No. 7 had a high bulk density, an elongation percentage within a predetermined range, and was further excellent in conductivity and strength. For example, even when the sintered body of Example 3 was used for a long time as a separator (100 × 100 × 3 mm) of a solid oxide fuel cell and the temperature was raised and lowered, no damage was observed in the zirconia electrolyte or the like.
【００４９】比較例１及び３の焼結体は、本発明の焼結
体とは組成が異なるものであり、酸素分圧１０-16 atm
の加湿水素雰囲気中１０００℃で１０時間熱処理した後
の室温での伸び率が大きく、曲げ強さも低い値であっ
た。比較例２の焼結体については、組成は本発明焼結体
と同様であるが、かさ密度が低く通気性があった。従っ
て、伸び率、導電率及び曲げ強さの測定は行なわなかっ
た。また、本発明の焼結体とは組成が異なるものである
比較例４の焼結体は緻密なものとなったが、空気中に放
置していたところ、数日後には非常に脆くなっていた。
従って、比較例２と同様にその他の特性の測定は行なわ
なかった。これを粉末にし、Ｘ線回折法により分析した
ところ、ＬａＣｒＯ3 のピーク以外に、Ｌａ2 Ｏ3 のピ
ークが認められた。比較例１〜４の焼結体を固体電解質
型燃料電池のセパレータに使用したところ、比較例１、
３及び４の焼結体を用いた場合には、使用後２４０時間
程度でセパレータまたはジルコニア電解質に割れが発生
する現象が認められ、比較例２の焼結体を用いた場合に
はガスのリークが認められた。The sintered bodies of Comparative Examples 1 and 3 have different compositions from the sintered body of the present invention, and have an oxygen partial pressure of 10 −16 atm.
After heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere, the elongation at room temperature was large and the bending strength was low. The composition of the sintered body of Comparative Example 2 was the same as that of the sintered body of the present invention, but had low bulk density and air permeability. Therefore, the elongation, conductivity, and bending strength were not measured. The sintered body of Comparative Example 4 having a different composition from that of the sintered body of the present invention was dense, but when left in the air, became very brittle after several days. Was.
Therefore, other characteristics were not measured as in Comparative Example 2. This was powdered and analyzed by an X-ray diffraction method. As a result, a La 2 O 3 peak was observed in addition to the LaCrO 3 peak. When the sintered bodies of Comparative Examples 1 to 4 were used for a separator of a solid oxide fuel cell, Comparative Example 1
When the sintered bodies of Nos. 3 and 4 were used, a phenomenon that cracks occurred in the separator or the zirconia electrolyte was observed in about 240 hours after use, and when the sintered body of Comparative Example 2 was used, gas leakage was observed. Was observed.
【００５０】[0050]
Claims (2)
1-y-z Ｍy Ｂz ）b Ｏ3 （式中、ＡはＣａ及びＳｒの少
なくとも一種を示し、０＜ｘ≦０．２であり、ＭはＣｏ
及びＮｉの少なくとも一種を示し、０＜ｙ≦０．１であ
り、ＢはＡｌ及びＭｇの少なくとも一種を示し、０＜ｚ
≦０．１であり、０＜ｙ＋ｚ≦０．１８、０．９５≦ａ
／ｂ≦１．０２である）で表されるペロブスカイト型結
晶構造を有する焼結体であり、（２）焼結体のかさ密度
が理論密度の９２％以上、（３）１０００℃での酸素分
圧が１０-16 atm となる加湿水素雰囲気中１０００℃で
１０時間熱処理した後の室温での焼結体の伸び率が０.
１５％以下、（４）１０００℃での酸素分圧が１０-16
atm となる加湿水素雰囲気中１０００℃における導電率
が０. ５Ｓ／ｃｍ以上、（５）室温曲げ強さが１０ｋｇ
ｆ／ｍｍ2 以上であり、且つ１０００℃での酸素分圧が
１０-16 atm となる加湿水素雰囲気中１０００℃で１０
時間熱処理した後の焼結体の室温曲げ強さが８ｋｇｆ／
ｍｍ2 以上であることを特徴とする耐熱導電性セラミッ
クス。(1) Chemical formula (La 1-x A x ) a (Cr
1-yz M y B z) b O 3 ( in the formula, A represents at least one of Ca and Sr, an 0 <x ≦ 0.2, M is Co
And at least one of Ni and 0 <y ≦ 0.1, B represents at least one of Al and Mg, and 0 <z
≦ 0.1, 0 <y + z ≦ 0.18, 0.95 ≦ a
/B≦1.02), (2) the sintered body has a bulk density of at least 92% of the theoretical density, and (3) oxygen at 1000 ° C. After a heat treatment at 1000 ° C. for 10 hours in a humidified hydrogen atmosphere having a partial pressure of 10 −16 atm, the elongation of the sintered body at room temperature is 0.1%.
(4) Oxygen partial pressure at 1000 ° C. is 10 −16 or less.
Conductivity of at least 0.5 S / cm at 1000 ° C. in a humidified hydrogen atmosphere atm, (5) Room temperature flexural strength of 10 kg
f / mm 2 or more and at 1000 ° C. in a humidified hydrogen atmosphere where the oxygen partial pressure at 1000 ° C. is 10 −16 atm.
Room temperature bending strength of the sintered body after heat treatment for 8 hours
mm 2 or more.
y Ｂz ）b Ｏ3 で表される焼結体のＬａの５０モル％以
下をイットリウム及び原子番号５８から７１の希土類元
素の少なくとも一種で置換したものである請求項１に記
載の耐熱導電性セラミックス。2. The chemical formula (La 1-x A x ) a (Cr 1-yz M
y B z) b O 3 in heat conductivity as claimed in claim 1 or less 50 mole% of La sintered body is obtained by replacing at least one rare earth element from yttrium and atomic number 58 71 represented Ceramics.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6190214A JP2612545B2 (en) | 1994-08-12 | 1994-08-12 | Heat-resistant conductive ceramics |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6190214A JP2612545B2 (en) | 1994-08-12 | 1994-08-12 | Heat-resistant conductive ceramics |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0859341A JPH0859341A (en) | 1996-03-05 |
| JP2612545B2 true JP2612545B2 (en) | 1997-05-21 |
Family
ID=16254373
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6190214A Expired - Lifetime JP2612545B2 (en) | 1994-08-12 | 1994-08-12 | Heat-resistant conductive ceramics |
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| Country | Link |
|---|---|
| JP (1) | JP2612545B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11322412A (en) | 1998-05-13 | 1999-11-24 | Murata Mfg Co Ltd | Multiple oxide ceramic material and solid electrolyte fuel cell |
| JP5885878B1 (en) * | 2014-12-26 | 2016-03-16 | 日本碍子株式会社 | Interconnector material |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3134882B2 (en) * | 1990-03-30 | 2001-02-13 | 東燃ゼネラル石油株式会社 | Lanthanum chromite complex oxides and applications |
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1994
- 1994-08-12 JP JP6190214A patent/JP2612545B2/en not_active Expired - Lifetime
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| Publication number | Publication date |
|---|---|
| JPH0859341A (en) | 1996-03-05 |
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