JP2002029742A - Rare earth oxide powder and method for manufacturing the same - Google Patents
Rare earth oxide powder and method for manufacturing the sameInfo
- Publication number
- JP2002029742A JP2002029742A JP2000220677A JP2000220677A JP2002029742A JP 2002029742 A JP2002029742 A JP 2002029742A JP 2000220677 A JP2000220677 A JP 2000220677A JP 2000220677 A JP2000220677 A JP 2000220677A JP 2002029742 A JP2002029742 A JP 2002029742A
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- Prior art keywords
- rare earth
- earth metal
- powder
- metal oxide
- oxide powder
- Prior art date
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、新規な希土類金属
酸化物粉末及びその製造方法に関する。[0001] The present invention relates to a novel rare earth metal oxide powder and a method for producing the same.
【０００２】[0002]
【従来技術】酸化イットリウムに代表されるイットリウ
ム、スカンジウム、ランタニド系の希土類酸化物粉末
は、各種のセラミックスの原料として多用されている。
特に、酸化物系ファインセラミックスにおいては、主成
分として使用されるほか、焼結安定剤、焼結促進剤等の
助剤又は添加剤として使用されたり、あるいは各反応過
程における触媒として使用されており、その重要性は近
年ますます高まりつつある。2. Description of the Related Art Yttrium, scandium, and lanthanide-based rare earth oxide powders represented by yttrium oxide are widely used as raw materials for various ceramics.
In particular, in oxide-based fine ceramics, in addition to being used as a main component, they are used as auxiliaries or additives such as sintering stabilizers and sintering accelerators, or as catalysts in each reaction process. , Its importance has been increasing in recent years.
【０００３】これに対し、希土類金属酸化物粉末の焼結
は非常に困難と言われている。例えば、佃 (窯業協会
誌、84[12]585(1976))又は Greskovich (Ceramics Bull
etin:American Ceramics Society, 52[2]473(1973))に
よって報告されているように、イットリア（Ｙ2Ｏ3）を
比較的高密度で焼結させるためには約２２００℃で長時
間焼結させることが必要とされている。また、 Dutta
(Mat.Res.Bull., 4, 791(1969))らの報告では、ホット
プレス法による強制的な緻密化が必要とされている。こ
れらの技術では、焼結条件、焼結方法等を改良するもの
であるが、これらを改良しても希土類酸化物粉末の焼結
性を改善するのには限界がある。On the other hand, it is said that sintering of rare earth metal oxide powder is very difficult. For example, Tsukuda (Journal of the Ceramic Society of Japan, 84 [12] 585 (1976)) or Greskovich (Ceramics Bull
etin: As reported by the American Ceramics Society, 52 [2] 473 (1973)), to sinter yttria (Y 2 O 3 ) at a relatively high density, sintering at about 2200 ° C. for a long time is required. It is needed to be. Also, Dutta
(Mat. Res. Bull., 4, 791 (1969)) et al. Require forced densification by a hot press method. These techniques improve sintering conditions, sintering methods, and the like. However, even if these techniques are improved, there is a limit to improving the sinterability of the rare earth oxide powder.
【０００４】希土類金属酸化物粉末を主成分として焼結
体を作製する際に求められる特性の中で最も重要なもの
は焼結性である。Herring のスケール則（守吉他「セラ
ミックスの焼結」内田老鶴圃）等で示されているとお
り、粉末を構成している一次粒子の粒径を小さくするこ
とは個々の粉末が焼結する際の拡散距離を短くでき、粉
末の焼結特性を飛躍的に向上できる。The most important property required for producing a sintered body containing a rare earth metal oxide powder as a main component is sinterability. As indicated by Herring's scaling rule (Moriyoshi et al., “Sintering of Ceramics”, Uchida Lacquer), reducing the particle size of the primary particles that make up the powder is a problem when individual powders are sintered. Can be shortened, and the sintering characteristics of the powder can be dramatically improved.
【０００５】ところが、焼結性を向上させるということ
は、一次粒子の表面エネルギーが著しく高くなることを
意味する。すなわち、微粒子化するほど粒子間の静電引
力（物理的結合）等の作用が強くなって焼結特性を向上
させる反面、一次粒子の凝集力を強めることになり、粉
砕困難な二次粒子を形成しやすくなる。結局は、粉砕が
完全に行われない限りは焼結性を向上させることは困難
である。[0005] However, improving the sinterability means that the surface energy of the primary particles is significantly increased. In other words, as the particles become finer, the effect of electrostatic attraction (physical bonding) between the particles becomes stronger and the sintering characteristics are improved, but the cohesive force of the primary particles is increased, and secondary particles that are difficult to pulverize are reduced. It is easy to form. After all, it is difficult to improve sinterability unless grinding is performed completely.
【０００６】一般的にセラミックスの原料粉末を製造す
る場合は、溶液中でシュウ酸塩、水酸化物等の中間体を
形成し、この中間体を仮焼することによって目的とする
原料を得る。この中間体の母体として一次粒子が形成さ
れるが、一次粒子サイズは非常に微細なものであり、仮
焼途中で個々の一次粒子間の焼結が進行することによっ
て非常に強固なネック形成（粒子どうしが何らかの拡散
機構により化学結合を形成）がされると物理的結合の場
合より粉砕がさらに困難となる。強固な一次粒子の凝集
が生じたとき、これを粉砕するためにホットミル等の処
理時間の長い粉砕方法を適用したり、アトライター又は
振動ミルのような破砕性能の高い装置を使用しなければ
ならなくなる。また、これらによって粉砕を試みたとし
ても、凝集状態によってはある一定粒度までしか破砕が
進行しないことがある。最近、斎藤らの報告 (J.Am.Cer
am.Soc.,81[8]2023(1998))によれば、炭酸イットリウム
を中間体とし、これらの中間体を７００〜１１００℃に
仮焼し、得られた酸化イットリウム粉末を焼結すること
によって比較的緻密な透光性焼結体が作製されたとされ
ている。ところが、この報告の中の仮焼粉末の電子顕微
鏡写真では、一次粒子が強固なネックを形成しており、
これはさらなる焼結性改善の必要性を示唆している。In general, when producing a raw material powder for ceramics, an intermediate such as oxalate or hydroxide is formed in a solution, and the intermediate is calcined to obtain a desired raw material. Primary particles are formed as a base of this intermediate, but the primary particle size is very fine, and sintering between the individual primary particles progresses during calcination to form a very strong neck ( When the particles form a chemical bond by some kind of diffusion mechanism), the pulverization becomes more difficult than in the case of the physical bond. When strong primary particles are agglomerated, a grinding method with a long processing time such as a hot mill must be applied to grind the particles, or a device with high crushing performance such as an attritor or a vibration mill must be used. Disappears. Further, even if crushing is attempted by these methods, crushing may progress only to a certain particle size depending on the state of aggregation. Recently, a report by Saito et al. (J.Am.Cer
According to am. Soc., 81 [8] 2023 (1998)), using yttrium carbonate as an intermediate, calcining these intermediates to 700 to 1100 ° C., and sintering the obtained yttrium oxide powder. Thus, a relatively dense translucent sintered body was produced. However, in the electron micrograph of the calcined powder in this report, the primary particles form a strong neck,
This suggests the need for further improvement in sinterability.
【０００７】実用化段階にある希土類酸化物粉末の製法
としては、例えばイットリウムの無機酸溶液とアンモニ
ア水（又は苛性ソーダ水）を反応させて水酸化イットリ
ウムを沈殿させる方法がある。しかしながら、この沈殿
物は非晶質のゲル状沈殿物を形成しやすい。このゲル状
沈殿物はろ過性が悪いため、生産性が低く、さらに純水
洗浄による不純物除去が困難である。また、このゲル状
沈殿物では、その粒子形態、粒径等の制御が困難であ
る。As a method for producing a rare earth oxide powder at the stage of practical use, for example, there is a method in which an inorganic acid solution of yttrium is reacted with ammonia water (or caustic soda water) to precipitate yttrium hydroxide. However, this precipitate tends to form an amorphous gel-like precipitate. Since the gel-like precipitate has poor filterability, productivity is low, and it is difficult to remove impurities by washing with pure water. In addition, it is difficult to control the particle morphology and particle size of the gel precipitate.
【０００８】イットリウムの無機酸溶液と蓚酸とを反応
させて蓚酸イットリウムを沈殿させ、この沈殿物を仮焼
してＹ2Ｏ3粉末を得る方法がある。しかしながら、この
方法では、仮焼後の酸化物がフロック状の粗大かつ硬い
凝集粒子を形成しており、粉砕することが困難である。
また、イットリウム無機酸塩としてＹＣｌ3が一般的に
使用されているため、沈殿中に塩素が残存しやすく、仮
焼の際に塩化水素ガスが発生しやすいため、装置腐食や
環境対策を講じる必要もある。There is a method of reacting an inorganic acid solution of yttrium with oxalic acid to precipitate yttrium oxalate, and calcinating the precipitate to obtain a Y 2 O 3 powder. However, according to this method, the calcined oxide forms floc-like coarse and hard aggregated particles, which is difficult to pulverize.
In addition, since YCl 3 is generally used as an inorganic salt of yttrium, chlorine tends to remain during precipitation, and hydrogen chloride gas is easily generated during calcination. Therefore, it is necessary to take measures against equipment corrosion and environmental measures. There is also.
【０００９】イットリウムの無機酸溶液から蓚酸アンモ
ニウムの複塩を沈殿させる方法がある（例えば、特開平
５−２７９０２２号、特開平５−２７９０２３号、特開
昭５５−２８９０５号等）。しかしながら、これらの方
法では、沈殿形成前に蓚酸とアンモニアとを予め反応さ
せておく必要があり、そのプロセスが煩雑である。ま
た、これにより得られる粉末も焼結性等の点において改
善の余地がある。There is a method of precipitating a double salt of ammonium oxalate from an inorganic acid solution of yttrium (for example, JP-A-5-279022, JP-A-5-279023, JP-A-55-28905, etc.). However, in these methods, it is necessary to react oxalic acid and ammonia in advance before forming a precipitate, and the process is complicated. Further, the powder obtained thereby has room for improvement in terms of sinterability and the like.
【００１０】[0010]
【発明が解決しようとする課題】以上のように、従来技
術では、粉砕性、分散性、焼結性等のいずれかに問題が
あるため、緻密な希土類金属酸化物の焼結体を工業的規
模で提供することが困難ないしは不可能であるというの
が実情である。As described above, in the prior art, since there is a problem in any of pulverizability, dispersibility, sinterability, etc., a dense sintered body of rare earth metal oxide is industrially produced. The fact is that it is difficult or impossible to provide on a scale.
【００１１】従って、本発明の主たる目的は、これら従
来技術の問題を解消し、緻密な焼結体を与える希土類金
属酸化物粉末を提供することにある。Accordingly, it is a main object of the present invention to provide a rare earth metal oxide powder which solves the problems of the prior art and gives a dense sintered body.
【００１２】[0012]
【課題を解決するための手段】本発明者は、これら従来
技術の問題に鑑み、鋭意研究を重ねた結果、特定の性状
を有する希土類酸化物粉末が上記目的を達成できること
を見出し、ついに本発明を完成するに至った。Means for Solving the Problems In view of these problems of the prior art, the present inventors have conducted intensive studies, and as a result, have found that a rare earth oxide powder having a specific property can achieve the above object. Was completed.
【００１３】すなわち、本発明は、下記の希土類金属酸
化物粉末及びその製造方法に係るものである。That is, the present invention relates to the following rare earth metal oxide powder and a method for producing the same.
【００１４】１．平均粒径１０〜２００ｎｍの範囲内に
ある一次粒子からなる鱗片状二次粒子により構成される
ことを特徴とする希土類金属酸化物粉末。1. A rare-earth metal oxide powder comprising flaky secondary particles composed of primary particles having an average particle diameter in the range of 10 to 200 nm.
【００１５】２．希土類金属塩の水溶液中にアルカリ水
溶液を添加することにより中間体を生成させた後、当該
中間体を６００〜１０００℃で仮焼する方法であって、
（１）当該水溶液の温度が０〜５０℃であり、（２）ア
ルカリ水溶液の添加速度を当該希土類金属の酸化物１モ
ル当たり２〜３０モル／分とすることにより、上記第１
項に記載の希土類金属酸化物粉末を製造する方法。2. A method of producing an intermediate by adding an aqueous alkali solution to an aqueous solution of a rare earth metal salt, and then calcining the intermediate at 600 to 1000 ° C,
(1) The temperature of the aqueous solution is 0 to 50 ° C., and (2) the addition rate of the alkaline aqueous solution is 2 to 30 mol / min per 1 mol of the rare earth metal oxide.
The method for producing a rare earth metal oxide powder according to the above item.
【００１６】[0016]
【発明の実施の形態】１．希土類金属酸化物粉末 本発明の希土類金属酸化物粉末は、平均粒径１０〜２０
０ｎｍの範囲内にある一次粒子からなる鱗片状二次粒子
により構成されることを特徴とする。DETAILED DESCRIPTION OF THE INVENTION 1. Rare earth metal oxide powder The rare earth metal oxide powder of the present invention has an average particle size of 10 to 20.
It is characterized by being composed of flaky secondary particles consisting of primary particles in the range of 0 nm.
【００１７】本発明粉末における希土類金属としては特
に限定されず、スカンジウム、イットリウムのほか、ラ
ンタニド系列（ランタン、セリウム、プラセオジム、ネ
オジム、プロメチウム、サマリウム、ユウロピウム、ガ
ドリニウム、テルビウム、ジスプロシウム、ホルミウ
ム、エルビウム、ツリウム、イッテルビウム及びルテチ
ウム）が挙げられる。The rare earth metal in the powder of the present invention is not particularly limited. In addition to scandium and yttrium, lanthanide series (lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium) , Ytterbium and lutetium).
【００１８】一次粒子の平均粒径は通常１０〜２００ｎ
ｍ程度、好ましくは１５〜１７０ｎｍとする。平均粒径
が１０ｎｍ未満である場合又は２００ｎｍを超える場合
は、焼結性等が低下するおそれがあるので好ましくな
い。The average particle size of the primary particles is usually from 10 to 200 n.
m, preferably 15 to 170 nm. If the average particle size is less than 10 nm or more than 200 nm, sinterability and the like may be reduced, such being undesirable.
【００１９】本発明粉末は、上記一次粒子からなる鱗片
状（フレーク状）二次粒子により構成される。この二次
粒子のアスペクト比は通常１を超えるものであれば良い
が、好ましくは３〜１００程度、特に５〜９０とすれば
良い。本発明粉末のアスペクト比は、例えば合成時にお
けるアルカリ水溶液の添加速度（滴下速度）、溶液温
度、溶液濃度等により制御することができる。The powder of the present invention is composed of scale-like (flake-like) secondary particles composed of the above primary particles. The aspect ratio of the secondary particles may generally be more than 1, but is preferably about 3 to 100, and more preferably 5 to 90. The aspect ratio of the powder of the present invention can be controlled by, for example, the addition rate (dropping rate) of the aqueous alkali solution, the solution temperature, and the solution concentration during the synthesis.
【００２０】本発明粉末では、二次粒子が、実質的に一
次粒子が単層状に配列することにより構成されているこ
とが好ましい。このような二次粒子は、特に優れた粉砕
性を発揮することができる。本発明の効果を妨げない範
囲内において、一次粒子が単層状に配列することにより
構成されている二次粒子以外の二次粒子が含まれていて
も良い。例えば、部分的に一次粒子が二層になっている
二次粒子、全体的に二層以上になっている二次粒子等が
含まれていても良い。In the powder of the present invention, it is preferable that the secondary particles are constituted by substantially arranging the primary particles in a single layer. Such secondary particles can exhibit particularly excellent pulverizability. As long as the effects of the present invention are not impaired, secondary particles other than the secondary particles constituted by arranging the primary particles in a single layer may be included. For example, secondary particles in which primary particles partially have two layers, secondary particles in which two or more layers are entirely included, and the like may be included.
【００２１】二次粒子の平均粒径は特に限定されない
が、通常は５０〜２００００ｎｍ程度、好ましくは５０
〜１５０００ｎｍとすれば良い。また、二次粒子の平均
厚さも上記アスペクト比を満たす限り特に限定されない
が、通常は１０〜２００ｎｍ程度、好ましくは１５〜１
７０ｎｍとすれば良い。なお、本発明における平均厚さ
に関し、一次粒子が単層状で配列して構成していると想
定し、一次粒子の平均粒径をもって上記二次粒子の平均
厚さとする。The average particle size of the secondary particles is not particularly limited, but is usually about 50 to 20,000 nm, preferably 50 to 20,000 nm.
It may be set to 〜15000 nm. Also, the average thickness of the secondary particles is not particularly limited as long as it satisfies the above aspect ratio, but is usually about 10 to 200 nm, preferably 15 to 1 nm.
What is necessary is just to make it 70 nm. In addition, regarding the average thickness in the present invention, it is assumed that the primary particles are arranged in a single layer, and the average particle diameter of the primary particles is defined as the average thickness of the secondary particles.
【００２２】本発明粉末のＢＥＴ比表面積は特に限定的
でなく、最終製品の用途等に応じて適宜設定すれば良
い。通常は２〜５０ｍ2／ｇ程度、好ましくは１５〜３
５ｍ2／ｇとすれば良い。このような範囲にＢＥＴ比表
面積を設定することによって、より粉砕しやすい粉末と
することができる。２．希土類金属酸化物粉末の製造方法 本発明粉末の製造方法は、希土類金属塩の水溶液中にア
ルカリ水溶液を添加することにより中間体を生成させた
後、当該中間体を６００〜１０００℃で仮焼する方法で
あって、（１）当該水溶液の温度が０〜５０℃であり、
（２）アルカリ水溶液の添加速度を当該希土類金属の酸
化物１モル当たり２〜３０モル／分とすることにより、
上記１の希土類金属酸化物粉末を製造するものである。The BET specific surface area of the powder of the present invention is not particularly limited, and may be appropriately set according to the use of the final product. Usually about 2 to 50 m 2 / g, preferably 15 to 3
What is necessary is just 5 m < 2 > / g. By setting the BET specific surface area in such a range, a powder that can be more easily pulverized can be obtained. 2. Method for Producing Rare Earth Metal Oxide Powder In the method for producing the powder of the present invention, an intermediate is generated by adding an aqueous alkali solution to an aqueous solution of a rare earth metal salt, and then the intermediate is calcined at 600 to 1000 ° C. (1) the temperature of the aqueous solution is 0 to 50 ° C.,
(2) By setting the rate of addition of the aqueous alkali solution to 2 to 30 mol / min per 1 mol of the rare earth metal oxide,
This is for producing the rare earth metal oxide powder of the above item 1.
【００２３】希土類金属塩としては、水可溶性塩であれ
ば特に限定されない。例えば、希土類金属の硝酸塩、硫
酸塩、塩化物等の無機酸塩、あるいは希土類金属の酢酸
塩、シュウ酸塩等の有機酸塩等を使用することができ
る。これらは単独で又は２種以上で使用することができ
る。例えば、希土類金属がイットリアであればＹＣ
ｌ3、Ｙ（ＮＯ3）3、Ｙ（ＣＨ3ＣＯＯ）3等の塩類を用
いることができる。The rare earth metal salt is not particularly limited as long as it is a water-soluble salt. For example, inorganic acid salts such as nitrate, sulfate, and chloride of rare earth metal, and organic acid salts such as acetate and oxalate of rare earth metal can be used. These can be used alone or in combination of two or more. For example, if the rare earth metal is yttria, YC
Salts such as l 3 , Y (NO 3 ) 3 and Y (CH 3 COO) 3 can be used.
【００２４】希土類金属塩の水溶液の濃度は、用いる希
土類金属塩の種類等に応じて適宜設定すれば良いが、通
常は酸化物換算で０．０２〜０．３モル／リットル程
度、好ましくは０．０３〜０．２モル／リットルとすれ
ば良い。The concentration of the aqueous solution of the rare earth metal salt may be appropriately set depending on the kind of the rare earth metal salt to be used and the like, but is usually about 0.02 to 0.3 mol / l, preferably 0 to 0.3 mol / l in terms of oxide. It may be 0.03 to 0.2 mol / liter.
【００２５】次いで、上記水溶液にアルカリ水溶液を添
加する。添加方法は、例えば滴下により実施すれば良
い。アルカリの種類は特に限定されず、例えば水酸化ナ
トリウム、水酸化カリウム、炭酸水素ナトリウム、アン
モニア水（ＮＨ4ＯＨ）等が挙げられる。本発明では、
アルカリ水溶液の添加速度を当該希土類金属の酸化物１
モル当たり２〜３０モル／分程度、好ましくは１０〜２
０モル／分とする。Next, an aqueous alkaline solution is added to the above aqueous solution. The addition method may be, for example, dropping. The type of the alkali is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, and aqueous ammonia (NH 4 OH). In the present invention,
The rate of addition of the aqueous alkali solution is adjusted to the rare earth metal oxide 1
About 2 to 30 mol / min, preferably 10 to 2 per mol
0 mol / min.
【００２６】アルカリ水溶液の総添加量は、希土類金属
塩の水溶液中に含まれる希土類金属の当量又はそれ以上
となるようにすれば良い。すなわち、希土類金属塩の水
溶液を中和すれば良い。The total amount of the alkaline aqueous solution may be adjusted to be equal to or more than the equivalent of the rare earth metal contained in the aqueous solution of the rare earth metal salt. That is, the aqueous solution of the rare earth metal salt may be neutralized.
【００２７】本発明方法において、アルカリ水溶液を添
加する場合における希土類金属塩の水溶液の温度は、通
常０〜７０℃程度、好ましくは１０〜３５℃の範囲内に
制御する。上記温度が０℃未満の場合又は７０℃を超え
る場合は、粉砕性等が低下し、粉砕しにくい粉末が生成
されるおそれがある。In the method of the present invention, the temperature of the aqueous solution of the rare earth metal salt when the aqueous alkaline solution is added is generally controlled within the range of about 0 to 70 ° C., preferably 10 to 35 ° C. When the temperature is lower than 0 ° C. or higher than 70 ° C., the pulverizability or the like is reduced, and a powder which is difficult to pulverize may be generated.
【００２８】アルカリ水溶液の添加は、その添加が完了
した後における希土類金属塩の水溶液のｐＨが、通常
７．５〜９．５程度の範囲、特に８〜８．５の範囲を維
持できるようにすることが好ましい。The addition of the aqueous alkali solution is carried out so that the pH of the aqueous solution of the rare earth metal salt after the completion of the addition can be generally maintained in the range of about 7.5 to 9.5, particularly in the range of 8 to 8.5. Is preferred.
【００２９】アルカリ水溶液の添加により中間体が沈殿
物として生成する。一般に、中間体は鱗片状粒子からな
る粉末（粒子）により構成されている。例えば希土類金
属がイットリウムの場合は、鱗片状の結晶性水酸化イッ
トリウム、塩基性炭酸イットリウム等の粒子が沈殿物と
して生成する。An intermediate is formed as a precipitate by the addition of the aqueous alkali solution. Generally, the intermediate is composed of powder (particles) composed of flaky particles. For example, when the rare earth metal is yttrium, scaly particles of crystalline yttrium hydroxide, basic yttrium carbonate, etc. are generated as precipitates.
【００３０】生成した中間体は、ろ過、遠心分離等の公
知の固液分離方法により回収した後、必要に応じて水洗
しても良い。その後、必要に応じて乾燥処理を行うこと
もできる。乾燥方法は自然乾燥及び強制乾燥（加熱乾
燥）のいずれでも良く、強制乾燥の場合は通常５０〜１
５０℃程度で加熱すれば良い。The produced intermediate may be recovered by a known solid-liquid separation method such as filtration and centrifugation, and then washed with water as necessary. Thereafter, a drying treatment can be performed if necessary. The drying method may be either natural drying or forced drying (heat drying), and in the case of forced drying, usually 50 to 1
What is necessary is just to heat at about 50 degreeC.
【００３１】次に、上記中間体を６００〜１０００℃
（好ましくは６００〜９５０℃）で仮焼する。仮焼温度
が６００℃未満の場合は残留揮発成分が残留したり、焼
結密度が上がらなくなるおそれがある。また１０００℃
を超える場合は鱗片状二次粒子内部の一次粒子間の結合
が非常に強くなって粉砕性が低下するおそれがある。仮
焼雰囲気は特に限定されないが、通常は大気中又は酸化
性雰囲気中とすれば良い。仮焼時間は特に制限されず、
仮焼温度等に応じて適宜決定すれば良い。Next, the above intermediate is heated at 600 to 1000 ° C.
(Preferably at 600 to 950 ° C.). When the calcination temperature is lower than 600 ° C., there is a possibility that residual volatile components remain or the sintering density cannot be increased. 1000 ℃
If it exceeds 300, the bond between the primary particles inside the flaky secondary particles is very strong, and the pulverizability may be reduced. Although the calcining atmosphere is not particularly limited, it may be usually in the air or an oxidizing atmosphere. The calcination time is not particularly limited,
What is necessary is just to determine suitably according to a calcination temperature etc.
【００３２】本発明粉末を用いて焼結体等を製造する場
合は、例えば本発明の希土類金属酸化物粉末を含む原料
粉末を成形し、焼結すれば良い。本発明粉末を主原料と
して得られた焼結体のほか、副原料（例えば、焼結助
剤、ＺｒＯ2用安定化剤、Ａｌ合金用強化材等の添加
剤）として使用して得られた焼結体も本発明焼結体に包
含される。When a sintered body or the like is manufactured using the powder of the present invention, for example, a raw material powder containing the rare earth metal oxide powder of the present invention may be formed and sintered. In addition to the sintered body obtained using the powder of the present invention as a main raw material, the powder was obtained as an auxiliary raw material (for example, an additive such as a sintering aid, a stabilizer for ZrO 2 , or a reinforcing material for Al alloy). A sintered body is also included in the sintered body of the present invention.
【００３３】本発明では、成形に先立って必要により予
め粉砕することもできる。粉砕方法は公知の方法に従え
ば良く、例えばボールミル、振動ミル等を使用すること
ができる。粉砕後の平均粒径は、最終製品の使用目的等
に応じて適宜設定すれば良いが、通常は０．０１〜０．
５μｍ程度とすれば良い。本発明粉末は、容易に粉砕す
ることができる。In the present invention, pulverization can be performed in advance, if necessary, prior to molding. The pulverizing method may be in accordance with a known method, and for example, a ball mill, a vibration mill or the like can be used. The average particle size after pulverization may be appropriately set according to the purpose of use of the final product and the like, but is usually from 0.01 to 0.1.
It may be about 5 μm. The powder of the present invention can be easily pulverized.
【００３４】成形方法は、例えばプレス成形、ＣＩＰ
法、ドクターブレード法等の公知の成形方法を適宜採用
することができる。この場合、本発明の効果を妨げない
範囲内で原料粉末に公知の樹脂系バインダー、焼結助剤
等を適宜配合しても良い。The molding method is, for example, press molding, CIP
A known molding method such as a method and a doctor blade method can be appropriately adopted. In this case, a known resin-based binder, sintering aid, or the like may be appropriately blended with the raw material powder within a range that does not impair the effects of the present invention.
【００３５】上記成形体の焼結は、大気中又は酸化性雰
囲気中（好ましくは純酸素雰囲気中）で通常１６００〜
１７５０℃程度で実施すれば良い。仮焼時間は焼結温度
等に応じて適宜設定することができる。また、本発明で
は、必要に応じてホットプレス法により成形と焼結を同
時に実施しても良い。このようにして得られた本発明の
焼結体は高い相対密度を有し、通常は１６５０℃で３時
間焼成後の相対密度が９９％以上、好ましくは９９．５
％以上という高い値を示す。The sintering of the above-mentioned compact is usually carried out in the air or in an oxidizing atmosphere (preferably in a pure oxygen atmosphere) at a temperature of 1600 to 1600.
What is necessary is just to implement at about 1750 degreeC. The calcination time can be appropriately set according to the sintering temperature and the like. In the present invention, if necessary, molding and sintering may be performed simultaneously by a hot press method. The sintered body of the present invention thus obtained has a high relative density, and usually has a relative density of 99% or more after firing at 1650 ° C. for 3 hours, preferably 99.5.
%.
【００３６】[0036]
【発明の効果】本発明によれば、分散性、反応性、粉砕
性及び焼結性に優れた希土類金属酸化物粉末を提供する
ことができる。これにより、単成分系又は複合系の高密
度焼結体を比較的低い焼結温度で製造することが可能と
なる。その結果、単成分系及び複合系希土類酸化物セラ
ミックスを工業的規模で生産することが可能となる。According to the present invention, a rare earth metal oxide powder excellent in dispersibility, reactivity, pulverizability and sinterability can be provided. This makes it possible to produce a single component or composite high density sintered body at a relatively low sintering temperature. As a result, single component and composite rare earth oxide ceramics can be produced on an industrial scale.
【００３７】また、本発明粉末は容易に粉砕できること
から、非酸化物系セラミックスの焼結助剤、粉末冶金の
粒成長抑制剤等の添加剤として使用する場合には、使用
量が少量で済むだけでなく、それらの添加による悪影響
もないため、従来品を用いる場合よりも優れた特性を付
与することができる。Further, since the powder of the present invention can be easily pulverized, when used as an additive such as a sintering aid for non-oxide ceramics or a grain growth inhibitor for powder metallurgy, a small amount of the powder can be used. In addition, since there is no adverse effect due to the addition thereof, it is possible to impart characteristics superior to those in the case of using a conventional product.
【００３８】このように、本発明粉末は、焼結体の主原
料として使用できるほか、副原料として使用することが
できる。As described above, the powder of the present invention can be used not only as a main raw material of a sintered body but also as an auxiliary raw material.
【００３９】本発明粉末を主原料として得られる焼結体
としては、例えばＹ2Ｏ3焼結体等の単独酸化物焼結体の
ほか、Ｙ−Ｓｃ系酸化物焼結体、ＹＩＧ焼結体、ＹＡＧ
焼結体等のイットリウムを含むガーネット系、ペロブス
カイト系等の焼結体等が挙げられる。これらの焼結体
は、特に透光性材料、耐プラズマ・耐ハロゲン材料等と
して好適に使用できる。例えば透光性材料として赤外線
透過窓、レーザー発振子、放電灯発光管、蛍光体等の用
途、耐プラズマ・耐ハロゲン材料として金属溶融ルツ
ボ、プラズマエッチング半導体製造装置用内壁材・窓材
（監視窓）等の用途にそれぞれ有利である。そのほか、
超高温炉心管、水素焼結炉等の絶縁碍子等として使用す
ることも可能である。また、本発明粉末を主原料として
使用する場合、触媒等としてＬａＭｎＯ3粉末、ＬａＣ
ｅＯ3粉末等をそのまま使用することもできる。Examples of the sintered body obtained by using the powder of the present invention as a main raw material include a single oxide sintered body such as a Y 2 O 3 sintered body, a Y—Sc based oxide sintered body, and a YIG sintered body. Body, YAG
Examples of the sintered body include a garnet-based and perovskite-based sintered body containing yttrium, such as a sintered body. These sintered bodies can be suitably used as a translucent material, a plasma-resistant and halogen-resistant material, and the like. For example, as a translucent material, there are applications such as an infrared transmissive window, a laser oscillator, a discharge lamp arc tube, and a phosphor, a metal melting crucible as a plasma and halogen resistant material, an inner wall material and a window material for a plasma etching semiconductor manufacturing apparatus (a monitoring window) ) Is advantageous for each application. others,
It can be used as an insulator for an ultra-high temperature furnace tube, a hydrogen sintering furnace, or the like. When the powder of the present invention is used as a main raw material, LaMnO 3 powder, LaC
eO 3 powder or the like can be used as it is.
【００４０】また、本発明粉末を副原料として使用する
場合、例えば１）Ｓｉ3Ｎ4、ＳｉＣ、ＡｌＮ等の非酸化
物系焼結体の焼結助剤又は粉末冶金における焼結助剤、
２）ジルコニア焼結体等の安定化剤、着色剤、３）アル
ミニウム系合金等における強度増加剤、粒成長抑制剤等
の各種添加剤として使用できる。本発明粉末を添加剤と
して使用して得られた焼結体は、例えば上記１）では構
造材料、耐熱材料、絶縁材料等の用途、上記２）では酸
素イオン導電性セラミックス（固体電解質燃料電池、酸
素センサー等）、構造材料（光ファイバー用フェルール
カッター、粉砕メディア等）、上記３）では構造材料等
に有利である。When the powder of the present invention is used as an auxiliary material, for example, 1) a sintering aid for a non-oxide-based sintered body such as Si 3 N 4 , SiC, AlN or a sintering aid for powder metallurgy;
2) It can be used as various additives such as a stabilizer and a coloring agent for a zirconia sintered body and the like, and 3) a strength increasing agent and a grain growth inhibitor in an aluminum-based alloy and the like. The sintered body obtained by using the powder of the present invention as an additive is, for example, used in 1) above as a structural material, a heat-resistant material, an insulating material, etc., and in 2) described above, as an oxygen ion conductive ceramic (solid electrolyte fuel cell, Oxygen sensors, etc.), structural materials (ferrule cutter for optical fiber, crushing media, etc.), and the above 3) are advantageous for structural materials.
【００４１】本発明の希土類金属酸化物粉末は、これら
の用途に限られず、その他の電気・電子材料、医療材
料、構造材料等への応用に期待できる。The rare earth metal oxide powder of the present invention is not limited to these uses, and can be expected to be applied to other electric / electronic materials, medical materials, structural materials and the like.
【００４２】[0042]
【実施例】以下、実施例及び比較例を示し、本発明の特
徴とするところをより一層明確にする。但し、本発明の
範囲は、これら実施例に限定されるものではない。EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention. However, the scope of the present invention is not limited to these examples.
【００４３】実施例１ （１）粉末の合成 まず酸化イットリウム換算で０．０３モル／リットルの
Ｙ（ＮＯ3）3水溶液（５０リットル）中に０．８モル／
リットルのＮＨ4ＯＨ水溶液を添加して沈殿を形成させ
た。このときのＮＨ4ＯＨ水溶液の添加速度は、酸化イ
ットリウム１モル当たり１８モル／分とした。ＮＨ4Ｏ
Ｈ水溶液の添加完了後のｐＨは８．３であった。また、
ＮＨ4ＯＨ水溶液の添加中の溶液温度は１８〜２０℃と
なるように調節した。Example 1 (1) Synthesis of Powder First, 0.8 mol / l of a Y (NO 3 ) 3 aqueous solution (50 l) of 0.03 mol / l in terms of yttrium oxide was used.
One liter of aqueous NH 4 OH was added to form a precipitate. At this time, the addition rate of the aqueous NH 4 OH solution was 18 mol / min per mol of yttrium oxide. NH 4 O
The pH after completion of the addition of the H aqueous solution was 8.3. Also,
NH 4 solution temperature during the addition of OH aqueous solution was adjusted to 18-20 ° C..
【００４４】得られた鱗片状中間体は、フィルタープレ
スによりろ過し、純水による洗浄を５回繰り返した。洗
浄された中間体は、１００℃に加熱して付着水分を除去
した後、さらに６３０℃で５時間仮焼することによって
粉末を得た。The obtained scale-like intermediate was filtered by a filter press, and the washing with pure water was repeated 5 times. The washed intermediate was heated to 100 ° C. to remove adhering water, and then calcined at 630 ° C. for 5 hours to obtain a powder.
【００４５】次いで、容量２リットルのポットミルに上
記粉末３００ｇ、直径５ｍｍのＺｒＯ2製ボール１．２
ｋｇ及びエチルアルコール０．８リットルを加え、３時
間粉砕処理を行った。その後、エチルアルコールを蒸発
させ、乾燥した粉砕粉末を得た。得られた粉末を直径３
０ｍｍ、高さ１０ｍｍのタブレット形状に金型成形し、
さらに９８ＭＰａの成形圧でＣＩＰ（冷間等方圧プレ
ス）を行い、成形体を得た。この成形体を純酸素雰囲気
にて１６５０℃で３時間の焼結を行うことにより焼結体
を得た。Next, a ZrO 2 ball having a diameter of 5 mm and a diameter of 5 mm was placed in a 2 liter pot mill.
kg and 0.8 liter of ethyl alcohol were added, and pulverized for 3 hours. Thereafter, the ethyl alcohol was evaporated to obtain a dried pulverized powder. The obtained powder is diameter 3
Molded into a tablet shape of 0mm and height of 10mm,
Further, CIP (cold isostatic pressing) was performed at a molding pressure of 98 MPa to obtain a molded body. The compact was sintered at 1650 ° C. for 3 hours in a pure oxygen atmosphere to obtain a sintered body.
【００４６】表１には、上記粉末及び焼結体の特性を示
す。なお、表１中に示す各特性は以下のようにして測定
・算出した。 （１）粉末の一次粒子径及び二次粒子径（粉砕前） ＦＥ−ＳＥＭ（電界放射走査型電子顕微鏡）により観察
し、任意に選んだ１００個の粒子の粒径の平均値を示
す。 （２）アスペクト比 粒子の平均粒径を平均厚さで除した値を示す。 （３）比表面積 ＢＥＴ法により測定した値を示す。 （４）粉砕前及び粉砕後の平均粒子径 Ｘ線透過法により測定した値を示す。 （５）焼結後の相対密度 Ｙ2Ｏ3の理論密度（５．０３ｇ／ｃｍ3）に対する相対
密度（％）を示す。Table 1 shows the characteristics of the powder and the sintered body. In addition, each characteristic shown in Table 1 was measured and calculated as follows. (1) Primary particle diameter and secondary particle diameter of powder (before pulverization) The average value of the particle diameters of 100 arbitrarily selected particles observed by FE-SEM (field emission scanning electron microscope) is shown. (2) Aspect ratio Indicates the value obtained by dividing the average particle size of the particles by the average thickness. (3) Specific surface area The value measured by the BET method is shown. (4) Average particle diameter before and after pulverization The value measured by the X-ray transmission method is shown. (5) Relative density after sintering The relative density (%) with respect to the theoretical density (5.03 g / cm 3 ) of Y 2 O 3 is shown.
【００４７】[0047]
【表１】 [Table 1]
【００４８】実施例２〜９ ＮＨ4ＯＨ水溶液の添加速度及び仮焼温度を表１に示す
ように変更したほかは実施例１と同様にして粉末及び焼
結体を製造した。各粉末及び焼結体について実施例１と
同様にその物性を測定した。その結果を表１に示す。Examples 2 to 9 Powders and sintered bodies were produced in the same manner as in Example 1 except that the addition rate of the aqueous NH 4 OH solution and the calcination temperature were changed as shown in Table 1. The physical properties of each powder and sintered body were measured in the same manner as in Example 1. Table 1 shows the results.
【００４９】また、実施例９の粉末についてＦＥ−ＳＥ
Ｍによる観察を行った。そのイメージを図１に示す。図
１からも明らかなように、本発明粉末は鱗片状の二次粒
子から構成されていることがわかる。また、一次粒子が
単層状で配列することにより二次粒子が構成されている
こともわかる。Further, the powder of Example 9 was subjected to FE-SE
Observation with M was performed. The image is shown in FIG. As is clear from FIG. 1, it can be seen that the powder of the present invention is composed of scale-like secondary particles. It can also be seen that the secondary particles are constituted by arranging the primary particles in a single layer.
【００５０】比較例１〜６ ＮＨ4ＯＨ水溶液の添加速度及び仮焼温度を変更するこ
とにより、得られる粉末の一次粒子径及び二次粒子径が
表２に示すようにしたほかは実施例１と同様にして粉末
及び焼結体を製造した。各粉末及び焼結体について実施
例１と同様にその物性を測定した。その結果を表２に示
す。Comparative Examples 1 to 6 The primary and secondary particle diameters of the resulting powder were changed as shown in Table 2 by changing the rate of addition of the NH 4 OH aqueous solution and the calcination temperature. A powder and a sintered body were produced in the same manner as described above. The physical properties of each powder and sintered body were measured in the same manner as in Example 1. Table 2 shows the results.
【００５１】[0051]
【表２】 [Table 2]
【００５２】表１及び表２の対比からも明らかなよう
に、比較例の粉末は粉砕性が低く、低い相対密度の焼結
体しか得られないことがかわる。これに対し、本発明品
は粉砕性に優れ、焼結後の相対密度９９％以上を確実に
達成できることがわかる。As is clear from the comparison between Tables 1 and 2, the powder of Comparative Example has low pulverizability and only a sintered body having a low relative density can be obtained. On the other hand, it is understood that the product of the present invention has excellent pulverizability and can reliably achieve a relative density of 99% or more after sintering.
【図１】実施例９で製造された粉末（二次粒子）の粒子
構造を示すイメージ図である。FIG. 1 is an image diagram showing a particle structure of a powder (secondary particle) manufactured in Example 9.
Claims (8)
一次粒子からなる鱗片状二次粒子により構成されること
を特徴とする希土類金属酸化物粉末。1. A rare earth metal oxide powder comprising flaky secondary particles composed of primary particles having an average particle size in the range of 10 to 200 nm.
０である請求項１記載の希土類金属酸化物粉末。2. The scaly secondary particles have an aspect ratio of 5 to 10.
The rare earth metal oxide powder according to claim 1, wherein the value is 0.
請求項１又は２に記載の希土類金属酸化物粉末。3. The rare earth metal oxide powder according to claim 1, which has a BET specific surface area of 2 to 50 m 2 / g.
及び平均厚さ１０〜２００μｍである請求項１〜３のい
ずれかに記載の希土類金属酸化物粉末。4. The average particle size of the secondary particles is 50 to 20000 μm.
The rare earth metal oxide powder according to any one of claims 1 to 3, which has an average thickness of 10 to 200 µm.
配列することにより構成されている請求項１〜４のいず
れかに記載の希土類金属酸化物粉末。5. The rare earth metal oxide powder according to claim 1, wherein the secondary particles are constituted by substantially arranging primary particles in a single layer.
属酸化物粉末を含む原料粉末を成形し、焼成して得られ
た焼結体。6. A sintered body obtained by molding and firing a raw material powder containing the rare earth metal oxide powder according to claim 1.
を添加することにより中間体を生成させた後、当該中間
体を６００〜１０００℃で仮焼する方法であって、
（１）当該水溶液の温度が０〜５０℃であり、（２）ア
ルカリ水溶液の添加速度を当該希土類金属の酸化物１モ
ル当たり２〜３０モル／分とすることにより、請求項１
〜５のいずれかに記載の希土類金属酸化物粉末を製造す
る方法。7. A method for producing an intermediate by adding an aqueous alkali solution to an aqueous solution of a rare earth metal salt, and then calcining the intermediate at 600 to 1000 ° C.
(1) The temperature of the aqueous solution is 0 to 50 ° C., and (2) the addition rate of the aqueous alkali solution is 2 to 30 mol / min per mol of the rare earth metal oxide.
A method for producing a rare earth metal oxide powder according to any one of claims 1 to 5.
金属の酸化物換算で０．０２〜０．３モル／リットルで
ある請求項７記載の製造方法。8. The method according to claim 7, wherein the concentration of the aqueous solution of the rare earth metal salt is 0.02 to 0.3 mol / liter in terms of the oxide of the rare earth metal.
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