JP2005247673A - Dy-DOPED NANO CERIA SINTERED COMPACT AND ITS MANUFACTURING METHOD - Google Patents

Dy-DOPED NANO CERIA SINTERED COMPACT AND ITS MANUFACTURING METHOD Download PDF

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JP2005247673A
JP2005247673A JP2004064616A JP2004064616A JP2005247673A JP 2005247673 A JP2005247673 A JP 2005247673A JP 2004064616 A JP2004064616 A JP 2004064616A JP 2004064616 A JP2004064616 A JP 2004064616A JP 2005247673 A JP2005247673 A JP 2005247673A
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sintered body
powder
nitrate
ammonium carbonate
temperature
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JP4729700B2 (en
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Toshiyuki Mori
利之 森
Yarong Wang
雅蓉 王
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National Institute for Materials Science
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    • 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
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    • Y02E60/50—Fuel cells
    • 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
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly electroconductive ceria sintered compact and its manufacturing method. <P>SOLUTION: By passing through a process for yielding a precipitated product of a precursor having a specified composition, a Dy-doped nano ceria spherical particle with a controlled shape, less aggregated, and good sinterability is produced. By sintering it, a dense sintered compact comprising particles with an average diameter of ≤100 nm is manufactured, by which its electroconductivity is drastically improved and a nano-sintered compact with high electroconductivity unobtainable by a conventional rare-earth element-doped ceria sintered compact is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、酸素センサ、炭酸ガスセンサ、一酸化窒素センサ、および燃料電池用固体電解質、などに利用されるＤｙドープナノセリア系焼結体およびその製造方法に関する。   The present invention relates to a Dy-doped nanoceria-based sintered body used for an oxygen sensor, a carbon dioxide gas sensor, a nitric oxide sensor, a solid electrolyte for a fuel cell, and the like, and a method for producing the same.

希土類元素をドープしたセリア系焼結体は、希土類元素としてサマリウム（Ｓｍ）やガドリウム（Ｇｄ）をドープしてなるセリア系焼結体は高導電率を有することで知られている。しかし、実際に焼結体を作製し、その導電率を測定してみると、その導電率は、直流３端子法で、７００℃でそれぞれ、-１．８および-１．５（Ｓ／ｃｍ）と十分なものではなかった。固体電解質を各種ガスセンサや燃料電池へ応用するには、低い温度で高い導電率を確保することが求められている。そうした中、Ｄｙ元素をドープしたセリア系焼結体は、１ミクロン以上の粒子径を有する場合、その伝導率は、ＳｍやＧｄなどをドープしたセリア系焼結体の値を下回る導電率（０．４ミクロンの粒径をもつＤｙ0.2Ｃｅ0.8Ｏ1.9
焼結体については、直流３端子法で、７００℃において-３．４Ｓ／ｃｍ）を持ち、その
低い導電率ゆえ、実用上有用な材料であるとは考えられていなかった。 A ceria-based sintered body doped with a rare earth element is known to have a high electrical conductivity, while a ceria-based sintered body doped with samarium (Sm) or gadolinium (Gd) as a rare earth element. However, when a sintered body was actually produced and its electrical conductivity was measured, the electrical conductivity was −1.8 and −1.5 (S / cm, respectively) at 700 ° C. by the direct current three-terminal method. ) And was not enough. In order to apply the solid electrolyte to various gas sensors and fuel cells, it is required to ensure high conductivity at a low temperature. Among these, when the ceria-based sintered body doped with the Dy element has a particle diameter of 1 micron or more, the conductivity is lower than the value of the ceria-based sintered body doped with Sm, Gd or the like (0 Dy 0.2 Ce 0.8 O 1.9 with 4 micron particle size
The sintered body had a direct current three-terminal method and had -3.4 S / cm at 700 ° C., and because of its low conductivity, it was not considered to be a practically useful material.

また、希土類ドープセリア焼結体の製造方法としては、サブミクロンの原料粉末から出発し、常圧焼結法を用いて、１４００℃以上の高温において焼結し、高密度焼結体を得る方法が採用されてきた。この方法において、サブミクロンの原料粉末は、セリウム塩と金属塩の混合溶液に、シュウ酸やアンモニアを沈殿剤として加えて均一沈殿を得る方法や、出発原料に金属アルコキシドを用いて、加水分解を行い、均一沈殿を作成する方法などが用いられてきた。こうして得られた均一沈殿物は、ろ過、乾燥、および仮焼を行い微粉末の合成を行ってきた。   In addition, as a method for producing a rare earth-doped ceria sintered body, there is a method of starting from a submicron raw material powder and sintering at a high temperature of 1400 ° C. or higher by using a normal pressure sintering method to obtain a high-density sintered body. Has been adopted. In this method, submicron raw material powder is hydrolyzed by adding oxalic acid or ammonia as a precipitating agent to a mixed solution of cerium salt and metal salt to obtain uniform precipitation, or by using metal alkoxide as a starting material. For example, methods have been used to create uniform precipitates. The uniform precipitate thus obtained has been filtered, dried and calcined to synthesize fine powder.

しかし、こうして得られた粉末は、凝集が大きいことから、結晶化温度が最低でも７００℃以上となり、そのため粒径がサブミクロンから１ミクロン程度と大きくなる。そのため、焼結温度が１６００℃以上であっても、焼結体内部に５体積％以上の空孔が残存し、この残存空孔が導電特性の低下をもたらすという欠点があった。アルコキシドを出発原料に用いる場合には、単分散粉末を作製することが可能であるが、アルコキシド原料が高価であることから、実用化に際しては、薄膜への応用に限定され、利用技術分野がきわめて限られることから、実用化の妨げとなっていた。   However, since the powder obtained in this way is highly agglomerated, the crystallization temperature is at least 700 ° C. or higher, and the particle size is increased from submicron to about 1 micron. Therefore, even when the sintering temperature is 1600 ° C. or higher, there is a drawback that 5% by volume or more of voids remain inside the sintered body, and this residual void causes a decrease in the conductive properties. When an alkoxide is used as a starting material, it is possible to produce a monodispersed powder. However, since the alkoxide raw material is expensive, it is limited to application to thin films in practical use, and the technical field of use is extremely high. Because it is limited, it has been a hindrance to practical use.

以上述べたように従来の希土類をドープしてなるセリア系焼結体は、導電性の点で充分でなく、また、製造プロセスにおいても導電性を妨げる要因となる空孔が存在する、あるいは特定の費用のかかる原料に依存せざるを得ない等いくつかの点で困難な問題があった。本発明は、このような問題のない高電導性セリア系焼結体とその製造方法を提供しようというものである。   As described above, conventional ceria-based sintered bodies doped with rare earths are not sufficient in terms of electrical conductivity, and there are pores that are a factor that impedes electrical conductivity in the manufacturing process, or are specified. However, there are some difficult problems such as having to rely on expensive materials. The present invention is to provide a highly conductive ceria-based sintered body free from such problems and a method for producing the same.

本発明者らは、上記従来技術の問題点に鑑み、鋭意検討を続けた結果、粒子の形状を制御し、凝集の少ない、球状粒子を作製することから準備したことは勿論、そのために粒子の前駆体である沈殿物質の組成、仮焼条件などについても検討を重ねた結果、易焼結性Ｄｙドープナノセリア粉末を作成し、この粉末を用いて焼結体内の平均粒子径が１００ｎｍ以下で、かつ緻密な焼結体を作成した場合に、劇的に導電率が向上し、これまでの希土類ドープセリア系焼結体にはない、高い導電性が現れることを見出し、本発明を完成するに
至った。 In light of the above-mentioned problems of the prior art, the present inventors have made intensive investigations, and as a result, prepared the preparation of spherical particles that control the shape of the particles and have less agglomeration. As a result of repeated investigations on the composition of precipitating substances, the pre-calcination conditions, etc., a sinterable Dy-doped nanoceria powder was prepared, and the average particle size in the sintered body was 100 nm or less using this powder. In addition, when a dense sintered body is prepared, the electrical conductivity is dramatically improved, and high conductivity that does not exist in the conventional rare earth-doped ceria-based sintered body appears, and the present invention is completed. It came.

すなわち本発明の上記課題を解決するための解決手段として講じた技術的構成は、以下（１）、（２）に記載する通りである。   That is, the technical configuration taken as a means for solving the above-described problems of the present invention is as described in (1) and (2) below.

（１） 一般式が、ＤｙxＣｅ1-xＯ2-δ（ただし、０．１０≦ｘ≦０．３０、 δ
はカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）または、（Ｄｙ1-aＳｒa）xＣｅ1-xＯ2-δ（ただし、０．１０≦ａ≦０．３、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）で表されるホタル石化合物からなるナノ粒子焼結体であって、焼結体の平均粒子径が平均１００ｎｍ以下であり、かつ焼結体密度が理論密度に対して９５％以上の値を有し、７００℃における直流３端子法における導電率が、-１（Ｓ／ｃｍ）以上であることを特徴とする、Ｄ
ｙドープ高電導性ナノセリア系焼結体。 (1) The general formula is Dy x Ce 1-x O 2- δ (where 0.10 ≦ x ≦ 0.30, δ
Represents an oxygen deficiency amount determined from the charge balance of cations and anions) or, (Dy 1-a Sr a ) x Ce 1-x O 2- δ ( although, 0.10 ≦ a ≦ 0.3, 0.10 ≦ x ≦ 0.30, where δ represents the amount of oxygen defects determined from the balance of charges of cations and anions) The average particle diameter is 100 nm or less on average, the sintered body density is 95% or more of the theoretical density, and the conductivity in the direct current three-terminal method at 700 ° C. is −1 (S / cm) D
y-doped highly conductive nanoceria-based sintered body.

（２） 組成式が、ＤｙxＣｅ1-xＯ2-δ（ただし、０．１０≦ｘ≦０．３、δ は
カチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）となるように混合するか、または（Ｄｙ1-aＳｒa）xＣｅ1-xＯ2-δ（ただし、０．１０≦ａ≦０．３、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）となるように、ディスプロシウム（Ｄｙ）硝酸塩とセリウム硝酸塩またはＤｙ硝酸塩、Ｓｒ硝酸塩とセリウム硝酸塩を混合し、この混合溶液と沈殿剤として炭酸アンモニウムを、（炭酸アンモニウム水溶液濃度）／（Ｍ硝酸塩水溶液濃度）、（ＭはＤｙまたはＤｙ＋Ｓｒを表す）のモル比が５から１０になるように混合して、Ｃｅ1-xＭx（ＮＨ3）y（ＣＯ3）z・Ｈ2ＯまたはＣｅ1-x（Ｍ1-aＳｒa）x（ＮＨ3）y（ＣＯ3）z・Ｈ2Ｏ（ただし、０．０５≦ｘ≦０．３、０．０５≦ｙ≦１、０．０５≦ｚ≦２および）で表されるセリウムアンモニウムカーボネートを沈殿させた後に、熟成を６０℃以上８０℃以下の温度で行い、洗浄後、４００℃以上６５０℃以下の温度において酸素気流中、仮焼することで、平均粒径２０ナノメーター以上５０ナノメーター以下の球状粒子を作成し、１０００℃以下の温度で焼結することで、相対密度の９５％以上の相対密度を持ち、７００℃における直流３端子法における導電率が、-１（Ｓ／ｃｍ）以上であることを特徴とする、高電導性Ｄｙドープナノセリア系焼結体の製造方法。 (2) The composition formula is Dy x Ce 1-x O 2- δ (where 0.10 ≦ x ≦ 0.3, δ represents the amount of oxygen defects determined from the charge balance between the cation and the anion) so as mixed in or (Dy 1-a Sr a) x Ce 1-x O 2- δ ( although, 0.10 ≦ a ≦ 0.3,0.10 ≦ x ≦ 0.30, δ is Dysprosium (Dy) nitrate and cerium nitrate or Dy nitrate, Sr nitrate and cerium nitrate are mixed so that the amount of oxygen defects determined from the balance of the cation and anion charges) As an agent, ammonium carbonate was mixed so that the molar ratio of (ammonium carbonate aqueous solution concentration) / (M nitrate aqueous solution concentration) (M represents Dy or Dy + Sr) was 5 to 10, and Ce 1-x M x (NH 3 ) y (CO 3 ) z · H 2 O or Ce 1-x (M 1- a Sr a) x (NH 3) y (CO 3) z · H 2 O ( although, 0.05 ≦ x ≦ 0.3,0.05 ≦ y ≦ 1,0. After cerium ammonium carbonate represented by 05 ≦ z ≦ 2 and) is precipitated, aging is performed at a temperature of 60 ° C. or more and 80 ° C. or less, and after washing, in a stream of oxygen at a temperature of 400 ° C. or more and 650 ° C. or less. By baking, spherical particles having an average particle diameter of 20 nanometers or more and 50 nanometers or less are prepared, and sintered at a temperature of 1000 ° C. or less, having a relative density of 95% or more of the relative density, at 700 ° C. A method for producing a highly conductive Dy-doped nanoceria-based sintered body, wherein the electrical conductivity in the direct current three-terminal method is -1 (S / cm) or more.

本発明は、上記特有なプロセスによって得られてなる原料を焼結体に使用することにより、セリア系焼結体の電導率を大幅に上げることに成功したものであり、今後、燃料電池を始め各種センサ等において使用され、それらの性能アップに大いに寄与するものと期待される。とりわけ、近年注目されている燃料電池の小型化、高出力化には大いに寄与するものと期待され、その意義は極めて大きいし、重大である。   The present invention has succeeded in significantly increasing the electric conductivity of the ceria-based sintered body by using the raw material obtained by the above specific process for the sintered body. It is used in various sensors, etc., and is expected to greatly contribute to improving their performance. In particular, it is expected to greatly contribute to miniaturization and high output of fuel cells that have been attracting attention in recent years, and its significance is extremely large and serious.

ここに、本発明の焼結体は、一般式：ＤｙxＣｅ1-xＯ2-δ（ただし、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）または、一般式：（Ｄｙ1-aＳｒa）xＣｅ1-xＯ2-δ（ただし、０．１０≦ａ≦０．３、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）で表されるホタル石化合物からなることが好ましい。該一般式中、ｘは、０．１０以上０．３０以下でなければならない。ｘが０．１０を下回ると、酸素欠陥量が不足していることから、いくら焼結体の粒子径を小さく制御しても、導電率の向上は期待できないことから好ましくない。一方、ｘが０．３０を上回ると、過剰な酸素欠陥が、結晶中において欠陥のクラスターを形成し、導電率を低下させることから、焼結体の粒径をナノサイズに制御しても、導電率の向上は見込めないことから好ましくない。 Here, the sintered body of the present invention has a general formula: Dy x Ce 1-x O 2- δ (where 0.10 ≦ x ≦ 0.30, δ is determined from the balance of charges of the cation and anion) oxygen defects represents the amount) or the general formula: (Dy 1-a Sr a ) x Ce 1-x O 2- δ ( although, 0.10 ≦ a ≦ 0.3,0.10 ≦ x ≦ 0.30 , Δ represents an oxygen defect amount determined from the balance of charges of the cation and anion). In the general formula, x must be 0.10 or more and 0.30 or less. If x is less than 0.10, the amount of oxygen defects is insufficient. Therefore, no matter how small the particle diameter of the sintered body is controlled, improvement in conductivity cannot be expected. On the other hand, when x exceeds 0.30, excessive oxygen defects form defect clusters in the crystal and lower the conductivity. Therefore, even if the grain size of the sintered body is controlled to nanosize, It is not preferable because improvement in conductivity cannot be expected.

また、一般式：（Ｄｙ1-aＳｒa）xＣｅ1-xＯ2-δにおいて、ａの値は、０．１以上０．３以下が好ましい。ａの値が０．１を下回ると、Ｓｒ元素が焼結体の粒成長を抑制する効果が十分に発揮されずに好ましくない。一方ａの値が０．３を上回ると、過剰のＳｒが焼結体の粒界に偏析し、焼結を阻害し、十分に高い密度が得られないので好ましくない。また、ｘは、０．１０以上０．３０以下が好ましい。この範囲を下回ると、酸素欠陥量が不足していることから、焼結体の粒子径を小さく制御しても、導電率の向上は期待できず、好ましくない。一方、ｘが０．３０を上回ると、過剰な酸素欠陥が、結晶中において欠陥のクラスターを形成し、導電率を低下させることから、焼結体の粒径をナノサイズに制御しても、導電率の向上は見込めず好ましくない。 Moreover, the general formula: In (Dy 1-a Sr a) x Ce 1-x O 2- δ, the value of a is preferably 0.1 to 0.3. When the value of a is less than 0.1, the Sr element is not preferable because the effect of suppressing the grain growth of the sintered body is not sufficiently exhibited. On the other hand, if the value of a exceeds 0.3, excess Sr is segregated at the grain boundaries of the sintered body, hindering sintering, and a sufficiently high density cannot be obtained, which is not preferable. Moreover, x is preferably 0.10 or more and 0.30 or less. Below this range, the amount of oxygen defects is insufficient, so even if the particle size of the sintered body is controlled to be small, improvement in conductivity cannot be expected, which is not preferable. On the other hand, when x exceeds 0.30, excessive oxygen defects form defect clusters in the crystal and lower the conductivity. Therefore, even if the grain size of the sintered body is controlled to nanosize, An improvement in conductivity cannot be expected, which is not preferable.

さらに、焼結体はホタル石結晶構造からなるものでなければならない。これ以外の結晶構造、すなわち原料物質であるＳｒやＤｙなどの酸化物に由来する、ホタル石結晶構造以外の構造の、アルカリ土類や希土類を含んだ構造のものが混在すると、最終生成物の伝導特性を著しく低下させることから好ましくない。
また、本発明における焼結体は、その平均粒子径が１００ｎｍ以下でなければならない。平均粒子径が１００ｎｍを上回り１ミクロン程度の場合には、粒界がかえって大きな抵抗要素となり、焼結体内部の導電特性を低下させ、導電率は低下するので好ましくない。 Furthermore, the sintered body must have a fluorite crystal structure. If a crystal structure other than this, that is, a structure other than the fluorite crystal structure derived from an oxide such as Sr or Dy, which is a raw material, is mixed with an alkaline earth or rare earth-containing structure, the final product This is not preferable because the conductive characteristics are significantly reduced.
The sintered body in the present invention must have an average particle size of 100 nm or less. When the average particle diameter exceeds 100 nm and is about 1 micron, the grain boundary is rather a large resistance element, which lowers the conductive characteristics inside the sintered body and lowers the conductivity, which is not preferable.

焼結体密度は、理論密度の９５％以上に緻密に作成することが好ましい。焼結体密度がこの値を下回ると、焼結体内部に取り残された空孔が、絶縁性を有するため、焼結体全体の導電性を著しく低下させるので好ましくない。
以上のべたように、化学組成、焼結体粒子径、および焼結体密度のすべての条件を満たすことによって、はじめて、従来にない高い導電特性である、７００℃において-１（Ｓ
／ｃｍ）以上の値が得られることが明らかにされた。 It is preferable that the density of the sintered body is densely set to 95% or more of the theoretical density. If the density of the sintered body is lower than this value, the voids left inside the sintered body have an insulating property, which is not preferable because the conductivity of the entire sintered body is significantly reduced.
As described above, by satisfying all the conditions of the chemical composition, the sintered body particle diameter, and the sintered body density, −1 (S
/ Cm) It has been clarified that a value of not less than can be obtained.

さらに、本発明におけるＤｙドープナノセリア系焼結体を作成するためには、まず易焼結性粉末の作成を行うことが必要不可欠である。こうした易焼結性粉末は、共沈法による均一沈殿法により作成が可能であるが、その際のセリウムカーボネートの化学組成は、Ｃｅ1-xＭx（ＮＨ3）y（ＣＯ3）z・Ｈ2ＯまたはＣｅ1-x（Ｍ1-aＳｒa）x（ＮＨ3）y（ＣＯ3）z・Ｈ2Ｏ（ただし、０．０５≦ｘ≦０．３、０．０５≦ｙ≦１、及び１．１０≦ｚ≦２．２４）とすることが好ましい。 Furthermore, in order to prepare the Dy-doped nanoceria-based sintered body in the present invention, it is indispensable to first prepare a sinterable powder. Such easily sinterable powder can be prepared by a uniform precipitation method using a coprecipitation method, and the chemical composition of cerium carbonate at that time is Ce 1-x M x (NH 3 ) y (CO 3 ) z. H 2 O or Ce 1-x (M 1- a Sr a) x (NH 3) y (CO 3) z · H 2 O ( although, 0.05 ≦ x ≦ 0.3,0.05 ≦ y ≦ 1 and 1.10 ≦ z ≦ 2.24).

上記組成式において、ｘの値は０．０５以上０．３以下の範囲が好ましい。この範囲を下回る場合は、上述のセンサ、燃料電池用固体電解質などへの応用に際して、仮焼粉末中に導入される酸素欠陥量が不足し、十分な特性が発揮されないので好ましくない。またこの範囲を上回ると、過剰な酸素欠陥が仮焼粉末中に導入され、かえって製品の特性を低下させるので好ましくない。   In the above composition formula, the value of x is preferably in the range of 0.05 to 0.3. If it falls below this range, the amount of oxygen defects introduced into the calcined powder will be insufficient when applied to the above-mentioned sensor, solid electrolyte for fuel cells, etc., and this is not preferable. On the other hand, exceeding this range is not preferable because excessive oxygen defects are introduced into the calcined powder, which deteriorates the properties of the product.

ｙの範囲は、０．０５以上１以下でなければならない。ｙの値は、反応溶液と沈殿剤のモル濃度比やｐＨにより制御されるものであり、ｙの値がこの範囲を下回ると十分に沈殿が生成せず、ろ液中に多量のセリウムなどの金属元素が残り、収率が低下するうえ、柱状粒子と球状粒子が混在した凝集体ができてしまい、焼結性を著しく低下させるので好ましくない。また、この範囲を上回ると粒子間の凝集が強くなり、サブミクロンの凝集体となり、焼結性が低下するので好ましくない。   The range of y must be 0.05 or more and 1 or less. The value of y is controlled by the molar concentration ratio and pH of the reaction solution and the precipitating agent. If the value of y falls below this range, precipitation does not occur sufficiently, and a large amount of cerium or the like is present in the filtrate. This is not preferable because the metal element remains, the yield is reduced, and an aggregate in which columnar particles and spherical particles are mixed is formed, and the sinterability is significantly reduced. On the other hand, if it exceeds this range, the aggregation between the particles becomes strong, resulting in a submicron aggregate and the sinterability is lowered, which is not preferable.

ｚの範囲は、１．１０以上２．２４以下が好ましい。このｚの値は、沈殿剤の濃度により制御可能であるが、この値が１．１０を下回ると十分に沈殿が生成せず、ろ液中に多量のセリウムなどの金属元素が残り、収率が低下するうえ、柱状粒子と球状粒子が混在した凝集体ができてしまい、焼結性を著しく低下させるので好ましくない。また、この範囲を上回ると粒子間の凝集が強くなり、サブミクロンの凝集体となり、焼結性が低下するので
好ましくない。 The range of z is preferably 1.10 or more and 2.24 or less. The value of z can be controlled by the concentration of the precipitating agent. However, when this value is less than 1.10, precipitation is not sufficiently generated, and a large amount of metal element such as cerium remains in the filtrate. In addition, an aggregate in which columnar particles and spherical particles are mixed is formed, and the sinterability is significantly reduced. On the other hand, if it exceeds this range, the aggregation between the particles becomes strong, resulting in a submicron aggregate and the sinterability is lowered, which is not preferable.

また、該式中ａの範囲は、０．０１以上０．３以下が好ましい。この範囲を下回るとＳｒ元素を共存させる効果が十分に発揮されず、上述のセンサ、燃料電池用固体電解質などへ利用した際、特性向上につながらないことから好ましくない。また、この範囲を上回るとＳｒ元素が偏析をおこし、かえって、センサ、燃料電池用固体電解質などの特性を低下させることがあるので好ましくない。   Further, the range of a in the formula is preferably 0.01 or more and 0.3 or less. Below this range, the effect of coexisting Sr element is not sufficiently exhibited, which is not preferable because it does not lead to improvement in characteristics when used in the above-described sensor, solid electrolyte for fuel cells, and the like. On the other hand, if it exceeds this range, the Sr element is segregated, and on the contrary, the characteristics of the sensor, solid electrolyte for fuel cell, etc. may be deteriorated, which is not preferable.

さらに、Ｓｒの硝酸塩、Ｄｙの硝酸塩およびセリウムの硝酸塩と炭酸アンモニウムを用いて沈殿を作製する場合、６０℃以上８０℃以下の温度で熟成を行なわなければならない。熟成温度がこの範囲を下回ると、沈殿中に柱状の粒子が共存してしまい、仮焼後にも、この柱状粒子が残存し、焼結性を低下させるので好ましくない。また、この温度範囲を超えるとせっかく生成した球状の粒子が凝集し、仮焼後もこの凝集がのこり、焼結性を著しく低下させるので好ましくない。   Further, when a precipitate is prepared using Sr nitrate, Dy nitrate, cerium nitrate and ammonium carbonate, aging must be performed at a temperature of 60 ° C. or higher and 80 ° C. or lower. If the aging temperature is lower than this range, the columnar particles coexist in the precipitation, and the columnar particles remain after calcination, which is not preferable. Further, if the temperature range is exceeded, the spherical particles generated with agglomeration are agglomerated, and this agglomeration remains after calcination, which is not preferable because the sinterability is significantly reduced.

熟成時間については特に制限はないが、あまり長時間の熟成をおこなってもそれなりの効果しかないので、１時間から２時間程度の熟成時間で十分である。
本発明に得られた沈殿物質は、沈殿生成後に水洗しなければならず、水洗を行わないと沈殿物質中に不純物が残存し、仮焼粉末の凝集を引き起こすために好ましくない。水洗の回数に特に制限はないが、３回以上の水洗を行うことで、ほぼ完全に不純物を除去できるので、３回以上の水洗を行うことが好ましい。 The aging time is not particularly limited, but a aging time of about 1 to 2 hours is sufficient because aging for a very long time has a certain effect.
The precipitated substance obtained in the present invention must be washed with water after the precipitation is formed, and if the washing is not performed, impurities remain in the precipitated substance, which causes agglomeration of the calcined powder. Although there is no restriction | limiting in particular in the frequency | count of water washing, since an impurity can be removed almost completely by performing water washing 3 times or more, it is preferable to perform water washing 3 times or more.

水洗後、粉末は乾燥不活性ガスなどを用いて乾燥を行い、空気中または酸素中で仮焼することで、結晶化させ、ホタル石型の結晶構造単一相にする必要があるが、その仮焼温度は４００℃以上６５０℃以下でなければならない。この温度範囲を下回ると、十分に結晶化が進まず、残存する非晶質が、焼結中に不均一な粒成長を引き起こし、緻密化を妨げることから好ましくない。またこの温度範囲を上回ると、サブミクロン以上の粒径になって、焼結に１６００℃以上の高温を必要とし、空孔が焼結体中に残りやすく、結果としてセンサや燃料電池用固体電解質の特性を低下させるので好ましくない。   After washing with water, the powder must be dried using a dry inert gas, etc., and calcined in air or oxygen to crystallize it into a single phase of fluorite-type crystal structure. The calcining temperature must be 400 ° C or higher and 650 ° C or lower. Below this temperature range, crystallization does not proceed sufficiently, and the remaining amorphous material causes non-uniform grain growth during sintering and prevents densification, which is not preferable. If the temperature range is exceeded, the particle size becomes submicron or larger, and a high temperature of 1600 ° C. or higher is required for sintering, and voids tend to remain in the sintered body. As a result, solid electrolytes for sensors and fuel cells are used. This is not preferable because the above characteristics are deteriorated.

仮焼の際の雰囲気は、空気中でも、酸素気流中でも同様な効果を得られるが、なるべく酸素分圧の高い雰囲気で仮焼することが、沈殿物質中に含まれる不純物を完全に燃焼させるうえで好ましい。また、仮焼時間についても特に制限はないが、低い温度で仮焼するほど、粉末中に炭酸ガスや水分が残りやすいので、４００℃または５００℃で仮焼する場合は、１０時間以上仮焼する必要があるが、それ以上の温度で仮焼する場合は、あまり長くしてもそれなりの効果しかないので、１時間から４時間程度仮焼すれば十分である。   The atmosphere during calcination can be obtained in air or in an oxygen stream, but calcination in an atmosphere with as high an oxygen partial pressure as possible is necessary to completely burn impurities contained in the precipitate. preferable. The calcining time is not particularly limited, but carbon dioxide gas and moisture are likely to remain in the powder as the calcining is performed at a lower temperature. Therefore, when calcining at 400 ° C. or 500 ° C., the calcining is performed for 10 hours or more. However, in the case of calcining at a temperature higher than that, it is sufficient to calcine for about 1 to 4 hours because there is only a certain effect even if it is too long.

得られた易焼結性粉末を焼結する方法には、特に制限はないが、大気中、９００℃以上１１００度以下の温度において、大気中で焼結することで相対密度９５％以上の高密度焼結体を作製することができるが、粒径を１００ナノメーター以下に制御するためには、１１００度以下の温度で焼結しなければならない。この温度を上回ると、焼結中に粒子が著しく成長し、平均粒径が１００nmを上回り、焼結体の電導率を低下させるので好ましくない。一方、この範囲を下回ると、十分に焼結体中の空孔が除去されず、焼結体密度が理論密度の９５％を下回り、電導率を低下させるので好ましくない。また、焼結時間については、特に制限はないが、あまり長時間の焼結をおこなっても、それなりの効果しか見込めないので、４時間程度の焼結を行えば十分である。   The method for sintering the obtained easily sinterable powder is not particularly limited. However, a high relative density of 95% or more is obtained by sintering in air at a temperature of 900 ° C. to 1100 ° C. A density sintered body can be produced, but in order to control the particle size to 100 nanometers or less, it must be sintered at a temperature of 1100 degrees or less. Above this temperature, the particles grow significantly during sintering, the average particle diameter exceeds 100 nm, and the conductivity of the sintered body is lowered, which is not preferable. On the other hand, if it is below this range, the pores in the sintered body are not sufficiently removed, and the density of the sintered body is less than 95% of the theoretical density, which is not preferable. Further, the sintering time is not particularly limited, but even if sintering is performed for a very long time, only a certain effect can be expected, so it is sufficient to perform the sintering for about 4 hours.

次に、本発明を実施例、図面及び比較例に基づいて説明する。但し、これらの実施例は、あくまでも本発明を具体的に示し、容易に理解するための一助として開示するものであって、本発明の内容は、これらの実施例により制限されるものではない。   Next, this invention is demonstrated based on an Example, drawing, and a comparative example. However, these examples are disclosed only as an aid for specifically showing and easily understanding the present invention, and the contents of the present invention are not limited by these examples.

実施例１；
組成がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０５モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウム水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリ・リットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６５℃の温度で、１時間熟成を行った。 Example 1;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.05 mol / liter dysprosium nitrate (purity 99.9) so that the composition was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the aqueous dysprosium nitrate solution to the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of ammonium carbonate dropping, aging was performed at a temperature of 65 ° C. for 1 hour.

こうして得られた沈殿は、水洗処理とろ過とを交互に３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は
引き続き、空気中７００℃の温度で１時間仮焼してセリア系化合物粉末を作成し、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。図１には、Ｘ線回折試験による結晶相の同定結果を示す。得られた仮焼粉末は、平均粒子径が３０ナノメーターの球状粒子であった。 The thus obtained precipitate was alternately washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 700 ° C. for 1 hour to prepare a ceria compound powder, and it was confirmed by an X-ray diffraction test that it consisted of a single crystal phase of fluorite. In FIG. 1, the identification result of the crystal phase by an X-ray diffraction test is shown. The obtained calcined powder was spherical particles having an average particle size of 30 nanometers.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行った。得られた焼結体は、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。得られた焼結体は、平均粒子径が９０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．８（Ｓ／ｃｍ）と高い値を示した。実施例１の結
果を表１、表２に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 and then sintered in air at 1000 ° C. for 4 hours. The obtained sintered body was densified to 99% of the theoretical density, and no large voids were observed on the surface of the sintered body, indicating that the densification was progressing. The obtained sintered body had an average particle diameter of 90 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as high as −0.8 (S / cm). The results of Example 1 are shown in Tables 1 and 2.

実施例２；
組成がＤｙ0.1Ｃｅ0.9Ｏ1.95になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）及び０．０２２モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウム水溶液と炭酸アンモニウム水溶液のモル比が、９となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリ・リットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.9Ｄｙ0.1（ＮＨ3）0.1（ＣＯ3）1.24・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を作成し、図１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。得られた仮焼粉末は、平均粒子径が３０ナノメーターの球状粒子であった。 Example 2;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.022 mol / liter dysprosium nitrate (purity 99.9) so that the composition was Dy 0.1 Ce 0.9 O 1.95. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the aqueous dysprosium nitrate solution to the aqueous ammonium carbonate solution is 9, and the aqueous ammonium carbonate solution is added to the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.9 Dy 0.1 (NH 3 ) 0.1 (CO 3 ) 1.24 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to prepare a ceria compound powder, and it was confirmed by an X-ray diffraction test that it consisted of a single crystal phase of fluorite as in FIG. . The obtained calcined powder was spherical particles having an average particle size of 30 nanometers.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行った。得られた焼結体は、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。得られた焼結体は、平均粒子径が９０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．９（Ｓ／ｃｍ）と高い値を示した。本実施例においても結果を表１、表２に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 and then sintered in air at 1000 ° C. for 4 hours. The obtained sintered body was densified to 99% of the theoretical density, and no large voids were observed on the surface of the sintered body, indicating that the densification was progressing. The obtained sintered body had an average particle diameter of 90 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as high as −0.9 (S / cm). Also in this example, the results are shown in Tables 1 and 2.

実施例３；
配合がＤｙ0.28Ｃｅ0.78Ｏ1.86になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）及び０．０５６モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウム水溶液と炭酸アンモニウム水
溶液のモル比が、８になるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリ(リットルの速度で滴下して沈殿を作製した。
炭酸アンモニウム滴下終了後、６５℃の温度で、１時間熟成処理を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.72Ｄｙ0.28（ＮＨ3）0.28（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。得られた仮焼粉末の平均粒子径は、３５ナノメーターであり、実施例１同様の球状粒子であった。 Example 3;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.056 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.28 Ce 0.78 O 1.86. %) Was prepared so that the molar ratio of the dysprosium nitrate aqueous solution and the ammonium carbonate aqueous solution was 8, and the ammonium carbonate aqueous solution was added to the starting material mixed aqueous solution at a rate of 1 mm / min. To prepare a precipitate.
After the ammonium carbonate dropping, aging treatment was performed for 1 hour at a temperature of 65 ° C. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.72 Dy 0.28 (NH 3 ) 0.28 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. As in Example 1, the calcined powder was confirmed to be composed of a single crystal phase of fluorite by an X-ray diffraction test. The average particle size of the obtained calcined powder was 35 nanometers, and the same spherical particles as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行った。こうして得られた焼結体は、実施例１同様、理論密の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が８０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．６（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 and then sintered in air at 1000 ° C. for 4 hours. The sintered body thus obtained was densified to 99% of the theoretical density as in Example 1, and no large voids were observed on the surface of the sintered body, indicating that the densification was progressing. It was.
The obtained sintered body had an average particle diameter of 80 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as high as −0.6 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例４；
組成がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０５モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウム水溶液と炭酸アンモニウム水溶液のモル比が、６となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリ・リットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、７５℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.8・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中４５０℃の温度で
１２時間仮焼してセリア系化合物粉末を作成し、図１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。得られた仮焼粉末は、平均粒子径が２５ナノメーターの球状粒子であった。 Example 4;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.05 mol / liter dysprosium nitrate (purity 99.9) so that the composition was Dy 0.2 Ce 0.8 O 1.9. %) Was used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the aqueous dysprosium nitrate solution to the aqueous ammonium carbonate solution was 6, and the aqueous ammonium carbonate solution was added to the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of ammonium carbonate dropping, aging was performed at a temperature of 75 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.8 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 450 ° C. for 12 hours to prepare a ceria compound powder, and it was confirmed by an X-ray diffraction test that it consisted of a single crystal phase of fluorite as in FIG. . The obtained calcined powder was spherical particles having an average particle size of 25 nanometers.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、９００℃、４時間
、空気中において焼結を行った。得られた焼結体は、理論密度の９６％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が８５ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．８（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 , followed by sintering in air at 900 ° C. for 4 hours. The obtained sintered body was densified to 96% of the theoretical density, and no large voids were observed on the surface of the sintered body, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 85 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as high as −0.8 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例５
組成が（Ｄｙ0.8Ｓｒ0.2）0.175Ｃｅ0.825Ｏ1.79になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０２８モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００７モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル比が、７となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリ・リットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６２℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.18（ＣＯ3）1.6・Ｈ2Ｏであっ
た。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を作成し、図１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。得られた仮焼粉末は、平均粒子径が２５ナノメーターの球状粒子であった。 Example 5
The starting material was 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.028 mol / liter dysprosium nitrate so that the composition would be (Dy 0.8 Sr 0.2 ) 0.175 Ce 0.825 O 1.79 (Purity 99.9%) and 0.007 mol / liter of strontium nitrate so that the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 7. Then, an aqueous ammonium carbonate solution was prepared, and the aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to produce a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 62 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.18 (CO 3 ) 1.6 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to prepare a ceria compound powder, and it was confirmed by an X-ray diffraction test that it consisted of a single crystal phase of fluorite as in FIG. . The obtained calcined powder was spherical particles having an average particle size of 25 nanometers.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、９００℃、４時間
、空気中において焼結を行った。得られた焼結体は、理論密度の９５％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が８５ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．７（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 , followed by sintering in air at 900 ° C. for 4 hours. The obtained sintered body was densified to 95% of the theoretical density, and no large voids were observed on the surface of the sintered body, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 85 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as high as −0.7 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例６；
配合が（Ｄｙ0.85Ｓｒ0.15）0.175Ｃｅ0.825Ｏ1.79になるように、出発原料として、０．２０モル／ｌの硝酸セリウム（純度９９．９９％）、０．０２９モル／ｌの硝酸ディスプロシウ（純度９９．９％）及び０．００５２モル／ｌの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、９になるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成処理を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.85Ｓｒ0.15）0.175（ＮＨ3）0.18（ＣＯ3）1.24・Ｈ2Ｏであった。前駆
体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３５ナノメーターであり、実施例１同様の球状粒子であった。 Example 6;
The starting material was 0.20 mol / l cerium nitrate (purity 99.99%) and 0.029 mol / l dysprosium nitrate (purity) so that the composition was (Dy 0.85 Sr 0.15 ) 0.175 Ce 0.825 O 1.79 99.9%) and 0.0052 mol / l of strontium nitrate, so that the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 9. An aqueous ammonium carbonate solution was prepared, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 ml / min to produce a precipitate. After ammonium carbonate dropping, aging treatment was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.85 Sr 0.15 ) 0.175 (NH 3 ) 0.18 (CO 3 ) 1.24 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. As in Example 1, the calcined powder was confirmed to be composed of a single crystal phase of fluorite by an X-ray diffraction test. Further, the average particle size of the calcined powder was 35 nanometers, and the same spherical particles as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が９０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．６（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 99% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 90 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as high as −0.6 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例７；
配合が（Ｄｙ0.75Ｓｒ0.25）0.175Ｃｅ0.825Ｏ1.79になるように、出発原料として、０．２０モル／ｌの硝酸セリウム（純度９９．９９％）、０．０２６モル／ｌの硝酸ディスプロシウ（純度９９．９％）及び０．００８７モル／ｌの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、６になるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、７５℃の温度で、１時間熟成処理を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.75Ｓｒ0.25）0.175（ＮＨ3）0.18（ＣＯ3）1.8・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中４５０℃の温度で１２時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３０ナノメーターであり、実施例１同様の球状粒子であった。 Example 7;
The starting material was 0.20 mol / l cerium nitrate (purity 99.99%) and 0.026 mol / l dysprosium nitrate (purity) so that the blending was (Dy 0.75 Sr 0.25 ) 0.175 Ce 0.825 O 1.79. 99.9%) and 0.0087 mol / l strontium nitrate, so that the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 6. An aqueous ammonium carbonate solution was prepared, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 ml / min to produce a precipitate. After the ammonium carbonate dropping, aging treatment was performed for 1 hour at a temperature of 75 ° C. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.75 Sr 0.25 ) 0.175 (NH 3 ) 0.18 (CO 3 ) 1.8 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 450 ° C. for 12 hours to obtain a ceria compound powder. As in Example 1, the calcined powder was confirmed to be composed of a single crystal phase of fluorite by an X-ray diffraction test. The average particle size of the calcined powder was 30 nanometers, which was the same spherical particle as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、９００℃、４時間
、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が９０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．６（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 900 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 99% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 90 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as high as −0.6 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例８；
配合が（Ｄｙ0.8Ｓｒ0.2）0.15Ｃｅ0.85Ｏ1.79になるように、出発原料として、０．２０モル／ｌの硝酸セリウム（純度９９．９９％）、０．０２７モル／ｌの硝酸ディスプロシウ（純度９９．９％）及び０．００６モル／ｌの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８になるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６５℃の温度で、１時間熟成処理を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.85（Ｄｙ0.8Ｓｒ0.2）0.15（ＮＨ3）0.15（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で２時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３５ナノメーターであり、実施例１同様の球状粒子であった。 Example 8;
The starting material was 0.20 mol / l cerium nitrate (purity 99.99%), 0.027 mol / l dysprosium nitrate (purity) so that the blending was (Dy 0.8 Sr 0.2 ) 0.15 Ce 0.85 O 1.79 99.9%) and 0.006 mol / l strontium nitrate, so that the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 ml / min to produce a precipitate. After the ammonium carbonate dropping, aging treatment was performed for 1 hour at a temperature of 65 ° C. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.85 (Dy 0.8 Sr 0.2 ) 0.15 (NH 3 ) 0.15 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 2 hours to obtain a ceria compound powder. As in Example 1, the calcined powder was confirmed to be composed of a single crystal phase of fluorite by an X-ray diffraction test. Further, the average particle size of the calcined powder was 35 nanometers, and the same spherical particles as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９８％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。得られた焼結体は、平均粒子径が８５ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．５（Ｓ／ｃｍ）と高い値を
示した。
本実施例の結果を表１、表２に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 98% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing. The obtained sintered body had an average particle diameter of 85 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as high as −0.5 (S / cm).
The results of this example are shown in Tables 1 and 2.

実施例９；
配合が（Ｄｙ0.8Ｓｒ0.2）0.25Ｃｅ0.75Ｏ1.79になるように、出発原料として、０．２０モル／ｌの硝酸セリウム（純度９９．９９％）、０．０４モル／ｌの硝酸ディスプロシウム（純度９９．９％）及び０．０１モル／ｌの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８になるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６５℃の温度で、１時間熟成処理を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.85（Ｄｙ0.8Ｓｒ0.2）0.15（ＮＨ3）0.15（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中４５０℃の温度で１２時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は２５ナノメーターであり、実施例１同様の球状粒子であった。 Example 9;
The starting material was 0.20 mol / l cerium nitrate (purity 99.99%) and 0.04 mol / l dysprosium nitrate so that the composition was (Dy 0.8 Sr 0.2 ) 0.25 Ce 0.75 O 1.79. (Purity 99.9%) and 0.01 mol / l of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After the ammonium carbonate dropping, aging treatment was performed for 1 hour at a temperature of 65 ° C. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.85 (Dy 0.8 Sr 0.2 ) 0.15 (NH 3 ) 0.15 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 450 ° C. for 12 hours to obtain a ceria compound powder. As in Example 1, the calcined powder was confirmed to be composed of a single crystal phase of fluorite by an X-ray diffraction test. Further, the average particle size of the calcined powder was 25 nanometers, and the same spherical particles as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、９００℃、４時間
、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９６％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んで
いることが分かった。
得られた焼結体は、平均粒子径が８０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-０．５（Ｓ／ｃｍ）と高い値を示した。
本実施例の結果を表１、表２に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 900 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 96% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 80 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as high as −0.5 (S / cm).
The results of this example are shown in Tables 1 and 2.

Figure 2005247673
Figure 2005247673


Figure 2005247673
Figure 2005247673

比較例１；
配合がＤｙ0.05Ｃｅ0.95Ｏ1.9になるように、出発原料として、０．２０モル／リット
ルの硝酸セリウム（純度９９．９９％）及び０．０１モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した
。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.95Ｄｙ0.05（ＮＨ3）0.05（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３０ナノメーターであり、実施例１同様の球状粒子であった。 Comparative Example 1;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.01 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.05 Ce 0.95 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.95 Dy 0.05 (NH 3 ) 0.05 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 30 nanometers, which was the same spherical particle as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９７％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が８５ナノメーターであったが、直流３端子法により、７００℃において測定した導電率は、-２．１（Ｓ／ｃｍ）と低い値を示した。本比較例
の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 97% of the theoretical density, and no large pores were observed on the sintered body surface, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 85 nanometers, but the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −2.1 (S / cm). . The results of this comparative example are shown in Tables 3 and 4.

比較例２；
配合がＤｙ0.4Ｃｅ0.6Ｏ1.95になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）及び０．０８モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.6Ｄｙ0.4（ＮＨ3）0.4（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３０ナノメーターであり、実施例１同様の球状粒子であった。 Comparative Example 2;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.08 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.4 Ce 0.6 O 1.95. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.6 Dy 0.4 (NH 3 ) 0.4 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 30 nanometers, which was the same spherical particle as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。
得られた焼結体は、平均粒子径が８５ナノメーターであったが、直流３端子法により、７００℃において測定した導電率は、-２．５（Ｓ／ｃｍ）と低い値を示した。本比較例
の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 99% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing.
The obtained sintered body had an average particle diameter of 85 nanometers, but the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −2.5 (S / cm). . The results of this comparative example are shown in Tables 3 and 4.

比較例３；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３
０ナノメーターであり、実施例１同様の球状粒子であった。 Comparative Example 3;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder is 3
It was 0 nanometer, and the spherical particles were the same as in Example 1.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１５００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、実施例１同様、理論密度の９９％にまで高密度化しており、焼結体表面には大きな空孔は認められず、ち密化が進んでいることが分かった。得られた焼結体は、平均粒子径が４２０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．４（Ｓ／ｃｍ）と低い値
を示した。本比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1500 ° C. for 4 hours. The resulting sintered body was the same as in Example 1. The density was increased to 99% of the theoretical density, and no large voids were observed on the sintered body surface, indicating that the densification was progressing. The obtained sintered body had an average particle diameter of 420 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as low as −3.4 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例４；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、９０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１４０ナノメーターであり、粒子が凝集した会合粒子であった。 Comparative Example 4;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 90 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 140 nanometers, and the particles were aggregated particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体の密度は、理論密度の９１％であり、焼結体表面には空孔が認められ、ち密化が十分には進んでいないことが分かった。得られた焼結体は、平均粒子径が２３０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-２．８（Ｓ／ｃｍ）と低い値を示した。本比較例の結
果を表３、表４に示した。 This powder was molded and then hydrostatically pressed at 2 t / cm 2 , and then sintered in air at 1000 ° C. for 4 hours. The density of the obtained sintered body was the theoretical density. It was found that voids were observed on the surface of the sintered body and densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 230 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method was as low as −2.8 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例５；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、４０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１００ナノメーターであり、球状粒子粒子が凝集した会合粒子であった。 Comparative Example 5;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 40 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 100 nanometers, and the particles were aggregated particles obtained by agglomerating spherical particle particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体の密度は、理論密度の８９％であり、焼結体表面には空孔が認められ、ち密化が進んでいないことが分かった。得られた焼結体は、平均粒子径が２６０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-２．６（Ｓ／ｃｍ）と低い値を示した。本比較例の結果を表３
、表４に示した。 This powder was molded and then hydrostatically pressed at 2 t / cm 2 , and then sintered in air at 1000 ° C. for 4 hours. The density of the obtained sintered body was the theoretical density. It was found that voids were observed on the surface of the sintered body and densification was not progressing. The obtained sintered body had an average particle diameter of 260 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as low as −2.6 (S / cm). Table 3 shows the results of this comparative example.
Table 4 shows.

比較例６；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中９００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は２３０ナノメーターであり、粒子が凝集した会合粒子であった。 Comparative Example 6;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the ammonium carbonate dropping, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 900 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 230 nanometers, and the particles were aggregated particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体の密度は、理論密度の８３％であり、焼結体表面には空孔が認められ、ち密化が進んでいないことが分かった。得られた焼結体は、平均粒子径が２７０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．３（Ｓ／ｃｍ）と低い値を示した。本比較例の結果を表３
、表４に示した。 This powder was molded and then hydrostatically pressed at 2 t / cm 2 , and then sintered in air at 1000 ° C. for 4 hours. The density of the obtained sintered body was the theoretical density. It was found that voids were observed on the surface of the sintered body and densification was not progressing. The obtained sintered body had an average particle diameter of 270 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as low as −3.3 (S / cm). Table 3 shows the results of this comparative example.
Table 4 shows.

比較例７；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）1.4・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温
度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は実施例１同様に、ホタル石単一の結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は２１０ナノメーターであり、粒子が凝集した会合粒子であった。 Comparative Example 7;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Is used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate and the aqueous ammonium carbonate solution is 8, and the aqueous ammonium carbonate solution is added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a single crystal phase of fluorite as in Example 1. The average particle size of the calcined powder was 210 nanometers, and the particles were aggregated particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体の密度は、理論密度の８１％であり、焼結体表面には空孔が認められ、ち密化が十分に進んでいないことが分かった。得られた焼結体は、平均粒子径が２８０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．１（Ｓ／ｃｍ）と低い値を示した。本比較例の結果
を表３、表４に示した。 This powder was molded and then hydrostatically pressed at 2 t / cm 2 , and then sintered in air at 1000 ° C. for 4 hours. The density of the obtained sintered body was the theoretical density. It was found that voids were observed on the surface of the sintered body and the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 280 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method showed a low value of −3.1 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例８；
配合がＤｙ0.2Ｃｅ0.8Ｏ1.9になるように、出発原料として、０．２０モル／リットル
の硝酸セリウム（純度９９．９９％）及び０．０４モル／リットルの硝酸ディスプロシウム（純度９９．９％）を用いて、硝酸ディスプロシウムの混合水溶液と炭酸アンモニウム水溶液のモル比が、１５となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られ
た沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.8Ｄｙ0.2（ＮＨ3）0.2（ＣＯ3）2.63・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中３００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は非晶質からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１５ナノメーターであり、球状粒子からなるものであった。 Comparative Example 8;
The starting materials were 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.04 mol / liter dysprosium nitrate (purity 99.9) so that the formulation was Dy 0.2 Ce 0.8 O 1.9. %) Was used to prepare an aqueous ammonium carbonate solution so that the molar ratio of the mixed aqueous solution of dysprosium nitrate to the aqueous ammonium carbonate solution was 15, and the aqueous ammonium carbonate solution was added to the starting aqueous solution mixture at a rate of 1 milliliter per minute. To prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.8 Dy 0.2 (NH 3 ) 0.2 (CO 3 ) 2.63 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 300 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was amorphous. The average particle size of the calcined powder was 15 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の７８％の密度を有するものであり、焼結体表面には大きな空孔が認められ、ち密化が十分には進んでいないことが分かった。得られた焼結体は、平均粒子径が８５ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．１（Ｓ／ｃｍ）と低い値を示し
た。本比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 78. %, And large pores were observed on the surface of the sintered body, indicating that the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 85 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method showed a low value of −3.1 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例９；
配合が（Ｄｙ0.95Ｓｒ0.05）0.175Ｃｅ0.825Ｏ1.81になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３３モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００１７モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.95Ｓｒ0.05）0.175（ＮＨ3）0.175（ＣＯ3）1.4・Ｈ2
Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は４０ナノメーターであり、球状粒子からなるものであった。 Comparative Example 9;
The starting material is 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.033 mol / liter dysprosium nitrate so that the composition is (Dy 0.95 Sr 0.05 ) 0.175 Ce 0.825 O 1.81 (Purity 99.9%) and 0.0017 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the result of chemical analysis of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.95 Sr 0.05 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 1.4 · H 2
O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 40 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、９００℃、４時間
、空気中において焼結を行ったところ、得られた焼結体は、理論密度の９８％の密度を有するものであり、焼結体表面には大きな空孔が認められず、ち密化が十分に進んでいることが分かった。得られた焼結体は、平均粒子径が９６ナノメーターであったが、直流３端子法により、７００℃において測定した導電率は、-１．９（Ｓ／ｃｍ）と低い値を示し
た。本比較例の結果を表３、表４に示した。 This powder was molded and then subjected to isostatic pressing at 2 t / cm 2 and then sintered in the air at 900 ° C. for 4 hours. As a result, the obtained sintered body had a theoretical density of 98. %, And no large voids were observed on the surface of the sintered body, indicating that the densification was sufficiently advanced. The obtained sintered body had an average particle diameter of 96 nanometers, but the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −1.9 (S / cm). . The results of this comparative example are shown in Tables 3 and 4.

比較例１０；
配合が（Ｄｙ0.6Ｓｒ0.4）0.175Ｃｅ0.825Ｏ1.75になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０２１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００１４モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.6Ｓｒ0.4）0.175（ＮＨ3）0.175（ＣＯ3）1.4・Ｈ2Ｏで
あった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により
確認した。また仮焼粉末の平均粒子径は３０ナノメーターであり、球状粒子からなるものであった。 Comparative Example 10;
The starting material is 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.021 mol / liter dysprosium nitrate so that the composition is (Dy 0.6 Sr 0.4 ) 0.175 Ce 0.825 O 1.75 (Purity 99.9%) and 0.0014 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the result of chemical analysis of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.6 Sr 0.4 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 30 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の９７％の密度を有するものであり、焼結体表面には大きな空孔が認められず、ち密化が十分に進んでいることが分かった。得られた焼結体は、平均粒子径が８４ナノメーターであったが、直流３端子法により、７００℃において測定した導電率は、-２．０（Ｓ／ｃｍ）と低い値を示
した。本比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 97 %, And no large voids were observed on the surface of the sintered body, indicating that the densification was sufficiently advanced. The obtained sintered body had an average particle diameter of 84 nanometers, but the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −2.0 (S / cm). . The results of this comparative example are shown in Tables 3 and 4.

比較例１１；
配合が（Ｄｙ0.9Ｓｒ0.1）0.175Ｃｅ0.825Ｏ1.92になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００３５モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.175（ＣＯ3）1.4・Ｈ2Ｏで
あった。前駆体粉末は引き続き、空気中９００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１２０ナノメータ-であり、球状粒子からなるも
のであった。 Comparative Example 11;
The starting material is 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.031 mol / liter dysprosium nitrate so that the composition is (Dy 0.9 Sr 0.1 ) 0.175 Ce 0.825 O 1.92 (Purity 99.9%) and 0.0035 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 900 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 120 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の７８％の密度を有するものであり、焼結体表面には大きな空孔が認められ、ち密化が十分に進んでいないことが分かった。得られた焼結体は、平均粒子径が１６０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．５（Ｓ／ｃｍ）と低い値を示し
た。本比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 78. %, And large pores were observed on the surface of the sintered body, indicating that the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 160 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as low as −3.5 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例１２；
配合が（Ｄｙ0.9Ｓｒ0.1）0.175Ｃｅ0.825Ｏ1.92になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００３５モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、１５となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、９０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.175（ＣＯ3）2.63・Ｈ2Ｏであった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１１５ナノメーターであり、球状粒子からなるものであった。 Comparative Example 12;
The starting material was 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.031 mol / liter dysprosium nitrate so that the composition would be (Dy 0.9 Sr 0.1 ) 0.175 Ce 0.825 O 1.92 (Purity 99.9%) and 0.0035 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 15. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 90 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 2.63 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 115 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の８５％の密度を有するものであり、焼結体表面には空孔が認められ、ち密化が十分に進んでいないことが分かった。得られた焼結体は、平均粒子径が１７０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．２（Ｓ／ｃｍ）と低い値を示した。本
比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 85. %, The pores were observed on the surface of the sintered body, and it was found that the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 170 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method was as low as −3.2 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例１３；
配合が（Ｄｙ0.9Ｓｒ0.1）0.175Ｃｅ0.825Ｏ1.92になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００３５モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、１となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、５０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.175（ＣＯ3）0.175・Ｈ2Ｏ
であった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１６０ナノメーターであり、球状粒子からなるものであった。 Comparative Example 13;
The starting material was 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.031 mol / liter dysprosium nitrate so that the composition would be (Dy 0.9 Sr 0.1 ) 0.175 Ce 0.825 O 1.92 (Purity 99.9%) and 0.0035 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 1. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 50 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the result of chemical analysis of the obtained precursor powder, the composition is Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 0.175 · H 2 O
Met. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 160 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の８２％の密度を有するものであり、焼結体表面には空孔が認められ、ち密化が十分に進んでいないことが分かった。得られた焼結体は、平均粒子径が２１０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．３（Ｓ／ｃｍ）と低い値を示した。本
比較例の結果を表３、表４に示した。 After the powder was molded, after hydrostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 82. %, The pores were observed on the surface of the sintered body, and it was found that the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 210 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −3.3 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例１４；
配合が（Ｄｙ0.9Ｓｒ0.1）0.175Ｃｅ0.825Ｏ1.92になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００３５モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.175（ＣＯ3）1.4・Ｈ2Ｏで
あった。前駆体粉末は引き続き、空気中３００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は非晶質相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は１５ナノメーターであり、球状粒子からなるものであった。 Comparative Example 14;
The starting material was 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.031 mol / liter dysprosium nitrate so that the composition would be (Dy 0.9 Sr 0.1 ) 0.175 Ce 0.825 O 1.92 (Purity 99.9%) and 0.0035 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the dropwise addition of ammonium carbonate, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 300 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of an amorphous phase. The average particle size of the calcined powder was 15 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１０００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の８５％の密度を有するものであり、焼結体表面には空孔が認められ、ち密化が十分に進んでいないことが分かった。得られた焼結体は、平均粒子径が１４０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．５（Ｓ／ｃｍ）と低い値を示した。本
比較例の結果を表３、表４に示した。 After this powder was molded and subjected to isostatic pressing at 2 t / cm 2 , sintering was performed in air at 1000 ° C. for 4 hours. The resulting sintered body had a theoretical density of 85. %, The pores were observed on the surface of the sintered body, and it was found that the densification was not sufficiently advanced. The obtained sintered body had an average particle diameter of 140 nanometers, and the conductivity measured at 700 ° C. by a direct current three-terminal method showed a low value of −3.5 (S / cm). The results of this comparative example are shown in Tables 3 and 4.

比較例１５；
配合が（Ｄｙ0.9Ｓｒ0.1）0.175Ｃｅ0.825Ｏ1.92になるように、出発原料として、０．２０モル／リットルの硝酸セリウム（純度９９．９９％）、０．０３１モル／リットルの硝酸ディスプロシウム（純度９９．９％）及び０．００３５モル／リットルの硝酸ストロンチウムを用いて、（硝酸ディスプロシウム水溶液＋硝酸ストロンチウム水溶液の合計）のモル数と炭酸アンモニウム水溶液のモル数比が、８となるように炭酸アンモニウム水溶液を調製し、出発原料混合水溶液中に炭酸アンモニウム水溶液を毎分１ミリリットルの速度で滴下して沈殿を作製した。炭酸アンモニウム滴下終了後、６０℃の温度で、１時間熟成を行った。こうして得られた沈殿は水洗処理とろ過を３回繰り返したのち、乾燥窒素ガス中において乾燥し、前駆体粉末を作製した。得られた前駆体粉末の化学分析結果から、その組成は、Ｃｅ0.825（Ｄｙ0.9Ｓｒ0.1）0.175（ＮＨ3）0.175（ＣＯ3）1.4・Ｈ2Ｏで
あった。前駆体粉末は引き続き、空気中６００℃の温度で１時間仮焼してセリア系化合物粉末を得た。仮焼粉末は図１同様、ホタル石型結晶相からなることをＸ線回折試験により確認した。また仮焼粉末の平均粒子径は３０ナノメーターであり、球状粒子からなるものであった。 Comparative Example 15;
The starting material was 0.20 mol / liter cerium nitrate (purity 99.99%) and 0.031 mol / liter dysprosium nitrate so that the composition would be (Dy 0.9 Sr 0.1 ) 0.175 Ce 0.825 O 1.92 (Purity 99.9%) and 0.0035 mol / liter of strontium nitrate, the molar ratio of the total number of (disprosium nitrate aqueous solution + strontium nitrate aqueous solution) and ammonium carbonate aqueous solution is 8. An aqueous ammonium carbonate solution was prepared as described above, and an aqueous ammonium carbonate solution was dropped into the starting raw material mixed aqueous solution at a rate of 1 milliliter per minute to prepare a precipitate. After completion of the ammonium carbonate dropping, aging was performed at a temperature of 60 ° C. for 1 hour. The precipitate thus obtained was repeatedly washed with water and filtered three times, and then dried in dry nitrogen gas to prepare a precursor powder. From the chemical analysis result of the obtained precursor powder, the composition was Ce 0.825 (Dy 0.9 Sr 0.1 ) 0.175 (NH 3 ) 0.175 (CO 3 ) 1.4 · H 2 O. The precursor powder was subsequently calcined in air at a temperature of 600 ° C. for 1 hour to obtain a ceria compound powder. It was confirmed by an X-ray diffraction test that the calcined powder was composed of a fluorite-type crystal phase as in FIG. The average particle size of the calcined powder was 30 nanometers and consisted of spherical particles.

この粉末を金型成形した後、２ｔ／ｃｍ2の静水圧成形を行った後、１５００℃、４時
間、空気中において焼結を行ったところ、得られた焼結体は、理論密度の９８％の密度を有するものであり、焼結体表面には大きな空孔が認められず、ち密化が十分に進んでいることが分かった。得られた焼結体は、平均粒子径が５１０ナノメーターであり、直流３端子法により、７００℃において測定した導電率は、-３．１（Ｓ／ｃｍ）と低い値を示し
た。本比較例の結果を表３、表４に示した。

Figure 2005247673


Figure 2005247673
 The powder was molded, then hydrostatically pressed at 2 t / cm 2 , and then sintered in air at 1500 ° C. for 4 hours. The resulting sintered body had a theoretical density of 98. %, And no large voids were observed on the surface of the sintered body, indicating that the densification was sufficiently advanced. The obtained sintered body had an average particle diameter of 510 nanometers, and the conductivity measured at 700 ° C. by the direct current three-terminal method showed a low value of −3.1 (S / cm). The results of this comparative example are shown in Tables 3 and 4.
Figure 2005247673

Figure 2005247673

以上の実施例、比較例を総合すると、本発明の特許請求の範囲で規定した、一般式に基づく組成式で規定される蛍石焼結体であって、平均粒子径、焼結体密度がそれぞれ特定の値を有してなる場合、その範囲外に比し極めて高い導電率を有することが明らかにされた
。すなわち、このデータによると特許請求の範囲で規定した各要件事項は、それぞれ格別意義のある事項を規定したものと言える。 Summarizing the above examples and comparative examples, the fluorite sintered body defined by the composition formula based on the general formula defined in the claims of the present invention, the average particle diameter, the sintered body density In the case where each has a specific value, it has been clarified that it has an extremely high conductivity as compared to outside the range. In other words, according to this data, it can be said that each requirement defined in the scope of claims defines a matter of exceptional significance.

近年、温暖化対策の一環として二酸化炭素削減が叫ばれる一方、高まるエネルギー需要に応えるために、高出力小型燃料電池の開発が活発に進められている。こうした燃料電池の開発には、５００℃から７００℃といった温度域で高い出力を示す燃料電池用固体電解質の研究、開発が必要不可欠である。本発明は、まさにこのニーズに対応した７００℃の温度で大きな電導率を示すセリア系焼結体固体電解質を提供するもので、今後大いに利用されることが期待される。また本発明の電導率の大きなセリア系焼結体固体電解質は、極めて多角的且つ基本的な観点に立脚してナノレベルで新たな知見を得、その上で開発することに成功したものであるところから、極めて安定した品質が保証され、今後は、燃料電池のみならず、各種技術分野において優れた固体電解質として供され、且つ利用されるものと期待される。とくに、耐熱性に優れた固体電解質であるところからその利用範囲は広く、新産業創出へと発展することが期待される。   In recent years, reduction of carbon dioxide has been called out as part of global warming countermeasures, while development of high-power small fuel cells has been actively promoted to meet increasing energy demand. For the development of such a fuel cell, research and development of a solid electrolyte for a fuel cell exhibiting a high output in a temperature range of 500 ° C. to 700 ° C. is indispensable. The present invention provides a ceria-based sintered solid electrolyte exhibiting a large electric conductivity at a temperature of 700 ° C. that exactly meets this need, and is expected to be used greatly in the future. In addition, the ceria-based sintered solid electrolyte having a high conductivity of the present invention has been successfully developed based on new knowledge at the nano level based on extremely diverse and basic viewpoints. Therefore, extremely stable quality is guaranteed, and it is expected that it will be used and used as an excellent solid electrolyte not only in fuel cells but also in various technical fields. In particular, since it is a solid electrolyte with excellent heat resistance, its range of use is wide and it is expected to develop into the creation of new industries.

本発明の製造方法で合成した焼結原料の結晶成分を示すＸ線回折図X-ray diffraction diagram showing crystal components of sintered raw material synthesized by the production method of the present invention

Claims (2)

一般式が、ＤｙxＣｅ1-xＯ2-δ（ただし、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）または、（Ｄｙ1-aＳｒa）xＣ
ｅ1-xＯ2-δ（ただし、０．１０≦ａ≦０．３、０．１０≦ｘ≦０．３０、δはカチオン
とアニオンの電荷のバランスから決定される酸素欠陥量を表す）で表される蛍石化合物からなるナノ粒子焼結体であって、焼結体の平均粒子径が平均１００ｎｍ以下であり、かつ焼結体密度が理論密度に対して９５％以上の値を有し、７００℃における直流３端子法における導電率の測定値が、-１（Ｓ／ｃｍ）以上であることを特徴とする、Ｄｙドープ高
電導性ナノセリア系焼結体。 The general formula is Dy x Ce 1-x O 2- δ (where 0.10 ≦ x ≦ 0.30, δ represents the amount of oxygen defects determined from the balance of charges of the cation and anion) or (Dy 1-a Sr a) x C
e 1-x O 2- δ (where 0.10 ≦ a ≦ 0.3, 0.10 ≦ x ≦ 0.30, δ represents the amount of oxygen defects determined from the balance of charges of the cation and anion) A sintered compact of a nanoparticle made of a fluorite compound represented by the formula, wherein the sintered body has an average particle diameter of 100 nm or less and a sintered body density of 95% or more of the theoretical density. And a Dy-doped highly conductive nanoceria-based sintered body, wherein a measured value of conductivity in a direct current three-terminal method at 700 ° C. is −1 (S / cm) or more. 組成式が、ＤｙxＣｅ1-xＯ2-δ（ただし、０．１０≦ｘ≦０．３、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）となるように混合するか、または（Ｄｙ1-aＳｒa）xＣｅ1-xＯ2-δ（ただし、０．１０≦ａ≦０．３、０．１０≦ｘ≦０．３０、δはカチオンとアニオンの電荷のバランスから決定される酸素欠陥量を表す）となるように、ディスプロシウム（Ｄｙ）硝酸塩とセリウム硝酸塩またはＤｙ硝酸塩、Ｓｒ硝酸塩とセリウム硝酸塩を混合し、この混合溶液と沈殿剤として炭酸アンモニウムを、（炭酸アンモニウム水溶液濃度）／（Ｍ硝酸塩水溶液濃度）、（ここでＭはＤｙまたはＤｙ＋Ｓｒを表す）のモル比が５から１０になるように混合して、Ｃｅ1-xＭx（ＮＨ3）y（ＣＯ3）z・Ｈ2ＯまたはＣｅ1-x（Ｍ1-aＳｒa）x（ＮＨ3）y（ＣＯ3）z・Ｈ2Ｏ（ただし、０．０５≦ｘ≦０．３、０．０５≦ｙ≦１及び１．１０≦ｚ≦２．２４）で表されるセリウムアンモニウムカーボネートを沈殿させた後に、熟成を６０℃以上８０℃以下の温度で行い、洗浄後、４００℃以上６５０℃以下の温度において酸素気流中、仮焼することで、平均粒径２０ナノメーター以上５０ナノメーター以下の球状粒子を作成し、１１００℃以下の温度で焼結することで、相対密度の９５％以上の相対密度を持ち、７００℃における直流３端子法における導電率の測定値が、-１（Ｓ／ｃｍ）以上であることを特徴とする、高
電導性Ｄｙドープナノセリア系焼結体の製造方法。
The composition formula is Dy x Ce 1-x O 2- δ (where 0.10 ≦ x ≦ 0.3, δ represents the amount of oxygen defects determined from the balance of charges of the cation and anion) or mixed, or (Dy 1-a Sr a) x Ce 1-x O 2- δ ( although, 0.10 ≦ a ≦ 0.3,0.10 ≦ x ≦ 0.30, δ cation and anion Dysprosium (Dy) nitrate and cerium nitrate or Dy nitrate, Sr nitrate and cerium nitrate are mixed so that carbon dioxide as a precipitating agent can be obtained. Ammonium was mixed so that the molar ratio of (ammonium carbonate aqueous solution concentration) / (M nitrate aqueous solution concentration) (where M represents Dy or Dy + Sr) was 5 to 10, and Ce 1-x M x ( NH 3) y (CO 3) z · H 2 O or e 1-x (M 1- a Sr a) x (NH 3) y (CO 3) z · H 2 O ( although, 0.05 ≦ x ≦ 0.3,0.05 ≦ y ≦ 1 and 1. After cerium ammonium carbonate represented by 10 ≦ z ≦ 2.24) is precipitated, aging is performed at a temperature of 60 ° C. or higher and 80 ° C. or lower, and after washing, in an oxygen stream at a temperature of 400 ° C. or higher and 650 ° C. or lower, By calcining, spherical particles having an average particle diameter of 20 nanometers or more and 50 nanometers or less are prepared, and sintered at a temperature of 1100 ° C. or less, having a relative density of 95% or more of the relative density, 700 ° C. A method for producing a highly conductive Dy-doped nano-ceria-based sintered body, wherein the measured value of conductivity in the direct current three-terminal method is -1 (S / cm) or more.
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JP2007022836A (en) * 2005-07-14 2007-02-01 Sumitomo Osaka Cement Co Ltd Method of manufacturing rare earth element-added cerium oxide powder
JP2007084413A (en) * 2005-09-26 2007-04-05 Anan Kasei Kk Method of manufacturing oxide sintered compact and raw material powder for oxide sintered compact
JP2008260673A (en) * 2007-03-20 2008-10-30 National Institute For Materials Science Rare earth element-doped ceria sintered body and its producing method
WO2009074549A1 (en) * 2007-12-10 2009-06-18 Höganäs Ab (Publ) Powder for electrolyte in fuel cells
CN101825551B (en) * 2009-07-23 2011-07-27 中国科学院过程工程研究所 Cerium dioxide microsphere used as dimension standard material
CN108178911A (en) * 2018-02-06 2018-06-19 叶剑 A kind of preparation method of rare earth modified nano material
WO2023109515A1 (en) * 2021-12-14 2023-06-22 安集微电子（上海）有限公司 Method for synthesizing cerium oxide and chemical mechanical polishing solution

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JPH092873A (en) * 1995-01-10 1997-01-07 Tosoh Corp Fluorite-type ceria-based solid electrolyte

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JPH092873A (en) * 1995-01-10 1997-01-07 Tosoh Corp Fluorite-type ceria-based solid electrolyte

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007022836A (en) * 2005-07-14 2007-02-01 Sumitomo Osaka Cement Co Ltd Method of manufacturing rare earth element-added cerium oxide powder
JP2007084413A (en) * 2005-09-26 2007-04-05 Anan Kasei Kk Method of manufacturing oxide sintered compact and raw material powder for oxide sintered compact
JP2008260673A (en) * 2007-03-20 2008-10-30 National Institute For Materials Science Rare earth element-doped ceria sintered body and its producing method
WO2009074549A1 (en) * 2007-12-10 2009-06-18 Höganäs Ab (Publ) Powder for electrolyte in fuel cells
CN101897062A (en) * 2007-12-10 2010-11-24 霍加纳斯股份有限公司 Powder for electrolyte in fuel cells
CN101825551B (en) * 2009-07-23 2011-07-27 中国科学院过程工程研究所 Cerium dioxide microsphere used as dimension standard material
CN108178911A (en) * 2018-02-06 2018-06-19 叶剑 A kind of preparation method of rare earth modified nano material
WO2023109515A1 (en) * 2021-12-14 2023-06-22 安集微电子（上海）有限公司 Method for synthesizing cerium oxide and chemical mechanical polishing solution

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