JP2547007B2 - Method for producing perovskite type oxide fine powder - Google Patents
Method for producing perovskite type oxide fine powderInfo
- Publication number
- JP2547007B2 JP2547007B2 JP62055291A JP5529187A JP2547007B2 JP 2547007 B2 JP2547007 B2 JP 2547007B2 JP 62055291 A JP62055291 A JP 62055291A JP 5529187 A JP5529187 A JP 5529187A JP 2547007 B2 JP2547007 B2 JP 2547007B2
- Authority
- JP
- Japan
- Prior art keywords
- urea
- type oxide
- perovskite type
- fine powder
- oxide fine
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Description
【発明の詳細な説明】 〔産業上の利用分野〕 本発明は尿素を用いた中和共沈法によるペロブスカイ
ト型酸化物微粉末の製造方法に関する。TECHNICAL FIELD The present invention relates to a method for producing perovskite type oxide fine powder by a neutralization coprecipitation method using urea.
ペロブスカイト型酸化物は一般にPbZrXTi1-XO3として
表わされる固溶体である。その粉末は強誘電体、圧電体
等の電気部材の原料として実用に供されている。The perovskite type oxide is a solid solution generally represented by PbZr X Ti 1-X O 3 . The powder is put to practical use as a raw material for electric members such as ferroelectrics and piezoelectrics.
用途上、より高い電気的特性（たとえば電気機械結合
係数）を要求されるため、該酸化物は高純度かつ平均粒
子径がサブミクロンのものが求められている。Since higher electrical characteristics (for example, electromechanical coupling coefficient) are required for use, the oxide is required to have high purity and an average particle size of submicron.
ペロブスカイト型酸化物粉末の製法は種々開発されて
いるが、製造コストが低く、かつ工程が簡単なアンモニ
ア中和共沈法（湿式法）が工業的に採用されている。Although various manufacturing methods of perovskite type oxide powder have been developed, an ammonia neutralization coprecipitation method (wet method) is industrially adopted because of low manufacturing cost and simple process.
この製法はPb,Zr,Tiの各金属水酸化物が水に難溶であ
ることに着眼して開発されたものであるすなわちPb,Zr,
Tiの各金属イオンを溶解させた混液にアンモニア水を滴
下するか、逆にアンモニア水に混液を滴下して混合溶液
をpH6〜８にし、Pb,Zr,Tiの各イオンを水酸化物として
共沈させ、得られた共沈物を過し、乾燥し、仮焼して
ペロブスカイト型酸化物粉末を製造する方法である。This manufacturing method was developed with a focus on the fact that the metal hydroxides of Pb, Zr, and Ti are poorly soluble in water, that is, Pb, Zr,
Ammonia water is added dropwise to the mixed solution in which each metal ion of Ti is dissolved, or conversely, the mixed solution is added to ammonia water to adjust the pH of the mixed solution to 6 to 8, and each ion of Pb, Zr, and Ti is used as a hydroxide. It is a method of producing a perovskite type oxide powder by precipitating the obtained coprecipitate, drying and calcining.
〔発明が解決しようとする問題点〕 前記アンモニア中和共沈法によつて製造された酸化物
粉末の一次粒子は細かく、かつ組成的にも均一である。
しかしこの方法では沈澱形成段階で生成した各沈澱物が
凝集しながら共沈し、その乾燥物は非常に固い団塊とな
り、仮焼後までその形状をとどめている。[Problems to be Solved by the Invention] The primary particles of the oxide powder produced by the ammonia neutralization coprecipitation method are fine and uniform in composition.
However, in this method, the respective precipitates formed in the precipitate forming step co-precipitate while coagulating, and the dried product becomes a very hard nodule, and its shape is retained until after calcination.
そこで該中和共沈法では一般に乾燥後の乾燥物あるい
は仮焼後の仮焼物を耐摩耗性のライニング、媒体を整備
した粉砕機を用いて粉砕して該酸化物の粉末を製造す
る。Therefore, in the neutralization coprecipitation method, generally, the dried product after drying or the calcined product after calcination is crushed using a crusher equipped with a wear resistant lining and a medium to produce the oxide powder.
しかしながら、上記粉砕方法は機械的手段によるた
め、平均粒子径はせいぜい数μｍ程度にしかならないこ
と、および粉砕も長時間に及ぶため、ライニング等の摩
耗による不純物の混入が避けられないことが、従来の中
和共沈法の重大な欠点であつた。However, since the above-mentioned pulverization method is a mechanical means, the average particle diameter is only about several μm at the most, and the pulverization takes a long time, so that mixing of impurities due to abrasion such as lining is inevitable. However, this is a serious drawback of the neutralization coprecipitation method.
そこで、本発明者らはアンモニア中和共沈法を改良し
て、粉砕工程を必要としないペロブスカイト型酸化物微
粉末の製造方法について研究した結果、アンモニアに替
えて尿素を採用することにより、従来法の欠点を解消で
きることを見い出して本発明を完成した。Therefore, the present inventors have improved the ammonia neutralization coprecipitation method, and as a result of research on a method for producing a perovskite type oxide fine powder that does not require a pulverization step, as a result of adopting urea instead of ammonia, The present invention has been completed by finding that the drawbacks of the law can be solved.
すなわち本発明はPb,Zr,Tiの各金属イオンを含む硝酸
溶液（以下単に「硝酸溶液」という）と、前記金属イオ
ンと反応し共沈させるに要する量以上の尿素を溶解させ
た水溶液（以下「尿素溶液」という）とを混合後、加熱
して尿素を分解させ、各金属イオンと反応させて水酸化
物とし共沈させ、得られた共沈物を過し、乾燥し、仮
焼してつくるペロブスカイト型酸化物の製造方法を要旨
とするものである。That is, the present invention is a nitric acid solution containing each metal ion of Pb, Zr, and Ti (hereinafter simply referred to as "nitric acid solution"), and an aqueous solution in which urea is dissolved in an amount equal to or greater than the amount required for coprecipitation by reacting with the metal ion (hereinafter (Urea solution)), then heat to decompose urea and react with each metal ion to form a hydroxide to coprecipitate. The coprecipitate obtained is dried, dried and calcined. The gist of the invention is a method for producing a perovskite type oxide.
以下、本発明を詳細に説明する。 Hereinafter, the present invention will be described in detail.
本発明に用いる尿素は純度の高い市販品が用いられ
る。As the urea used in the present invention, a commercially available product with high purity is used.
尿素溶液をつくるときに配合される尿素量は製造され
るペロブスカイト型酸化物１モルに対し、少なくとも３
モル以上、好ましい配合量は６〜30モルである。６モル
未満では各金属イオンが全量共沈しない場合があり、30
モルを超えれば仮焼物中に尿素が残存する場合もあるの
で、仮焼時間を非常に長くしなければならないことがあ
り、いずれも好ましくない。The amount of urea blended when preparing the urea solution is at least 3 per 1 mol of the perovskite type oxide produced.
The amount is not less than mol, and the preferable amount is 6 to 30 mol. If it is less than 6 moles, not all metal ions may coprecipitate.
If it exceeds the molar amount, urea may remain in the calcined product in some cases, so that the calcining time may have to be made very long, which is not preferable.
尿素を水に溶解する方法は、慣用の方法にしたがつて
尿素溶液をつくる。A method of dissolving urea in water is to prepare a urea solution according to a conventional method.
次に硝酸溶液のつくり方を説明する。 Next, a method of preparing a nitric acid solution will be described.
硝酸溶液をつくるにはPb,Zr,Tiの各金属原子を含む化
合物を濃硝酸に溶解させることによつてつくられる。溶
解方法は慣用方法による。化合物としては硝酸塩、オキ
シ硝酸塩等の無機化合物のほか、金属アルコキシド、酢
酸塩等の有機化合物などが示される。一つの化合物に上
記金属原子が２種以上含まれていることはさしつかえな
い。A nitric acid solution is prepared by dissolving a compound containing Pb, Zr, and Ti metal atoms in concentrated nitric acid. The dissolution method is a conventional method. Examples of the compound include inorganic compounds such as nitrates and oxynitrates, and organic compounds such as metal alkoxides and acetates. It does not matter that one compound contains two or more kinds of the above metal atoms.
化合物の配合割合はPb,Zr,Tiの各金属原子比が仮焼し
たさいに所望のペロブスカイト型酸化物になるような割
合にすればよく、本発明ではその比を特に限定しない。The compounding ratio of the compound may be such that each metal atomic ratio of Pb, Zr and Ti becomes a desired perovskite type oxide upon calcination, and the ratio is not particularly limited in the present invention.
次に共沈物のつくり方を説明する。 Next, how to make a coprecipitate will be described.
上記のようにしてつくられた硝酸溶液に尿素溶液を加
え、あるいはその逆に加え混液とする。このとき、Pb,Z
r,Tiの沈澱生成を防ぐため混液をpH2以下に保つことが
重要である。ついで混液を撹拌しながらその混液を加熱
する。加熱によつて尿素が分解し、Pb,Zr,Tiの各金属イ
オンと反応してそれぞれの金属水酸化物が生成し共沈す
る。A urea solution is added to the nitric acid solution prepared as described above, or vice versa, to form a mixed solution. At this time, Pb, Z
It is important to keep the pH of the mixture below 2 to prevent the precipitation of r and Ti. Then, the mixture is heated while stirring the mixture. Urea is decomposed by heating and reacts with each metal ion of Pb, Zr, and Ti to generate each metal hydroxide and coprecipitate.
混液の加熱温度は尿素を効率よく分解させるために管
理する必要がある。50℃未満では反応が終了せず収率が
悪くなる。また105℃を超えると尿素の分解により生じ
たアンモニアガスが水中に溶けこまずに系外に逃げ、未
反応の原料液が残って収率が悪くなるので加熱温度は50
〜105℃とする。尿素の添加量については少なすぎると
反応が終了せず収率が悪くなるので製造されるペロブス
カイト型酸化物１モルに対し、３モル以上は必要であ
る。The heating temperature of the mixed solution must be controlled in order to decompose urea efficiently. If the temperature is lower than 50 ° C, the reaction will not be completed and the yield will be poor. When the temperature exceeds 105 ° C, the ammonia gas generated by the decomposition of urea does not dissolve in water and escapes to the outside of the system, leaving unreacted raw material liquid and lowering the yield.
Set to ~ 105 ℃. If the amount of urea added is too small, the reaction will not be completed and the yield will be poor. Therefore, 3 mol or more is necessary for 1 mol of the perovskite oxide produced.
混液中に生成した共沈物は過され、乾燥される。得
られた乾燥物はほとんど一次粒子のフワフワした粉末状
である。The coprecipitate formed in the mixed solution is passed and dried. The obtained dried product is almost fluffy powdery particles.
得られた乾燥物は500〜1000℃、空気中で仮焼すれば
平均粒径がサブミクロンのペロブスカイト型酸化物微粉
末が得られる。The obtained dried product is calcined in air at 500 to 1000 ° C. to obtain perovskite type oxide fine powder having an average particle size of submicron.
本発明でつくられた乾燥物や仮焼物が従来法のように
団塊にならず、フワフワした粉末状になる理由は不詳で
あるが、次のように推定することができる。It is unclear why the dried or calcined product produced by the present invention does not become a lump and becomes a fluffy powder unlike the conventional method, but it can be estimated as follows.
すなわち混液の加熱によつて尿素が部分的に分解し、
尿素およびアンモニウムイオンとして存在し、混液をア
ルカリ性にする一方、イオン状態のPb,Zr,Tiの各金属は
アルカリと反応してゲル（水酸化物）を生成する。That is, the urea is partially decomposed by heating the mixed solution,
It exists as urea and ammonium ions and makes the mixed solution alkaline, while the ionic Pb, Zr, and Ti metals react with the alkali to form a gel (hydroxide).
このゲル表面に尿素および／またはアンモニウムイオ
ンが吸着し、各ゲル相互に反発し、凝集せずに共沈堆積
するために、その乾燥物も微細化されたフワフワした状
態になるものと思われる。It is considered that urea and / or ammonium ions are adsorbed on the surface of the gel, repel each other, and coprecipitate and deposit without agglomeration, so that the dried product also becomes a fine and fluffy state.
市販のオキシ硝酸ジルコニウム水溶液、チタンイソプ
ロポキシドおよび無水硝酸鉛を用いてペロブスカイト型
酸化物微粉末を製造した。A fine powder of perovskite type oxide was produced using a commercially available aqueous solution of zirconium oxynitrate, titanium isopropoxide and anhydrous lead nitrate.
オキシ硝酸ジルコニウム水溶液52.5ml（Zr0.3mol/
）に濃硝酸30mlを加えたのち、チタンイソプロポキシ
ド44.4ml（Ti3.32mol/）を滴下し、撹拌して透明な溶
液にした。この溶液に無水硝酸鉛101.0gを加え、溶解さ
せ、Pb,Zr,Tiの原子比が1:0.52:0.48の硝酸溶液をつく
つた。Zirconium oxynitrate aqueous solution 52.5 ml (Zr 0.3 mol /
After adding 30 ml of concentrated nitric acid to 4), 44.4 ml (Ti3.32 mol /) of titanium isopropoxide was added dropwise and stirred to form a transparent solution. To this solution, 101.0 g of anhydrous lead nitrate was added and dissolved to prepare a nitric acid solution having an atomic ratio of Pb, Zr, and Ti of 1: 0.52: 0.48.
一方、表１に示す尿素量を1800mlの純水に溶解させて
尿素溶液をつくつた。On the other hand, the urea amount shown in Table 1 was dissolved in 1800 ml of pure water to prepare a urea solution.
それら尿素溶液に硝酸溶液を加えてそれぞれの混液を
つくつたところ、各混液ともほぼpH1.6であつた。つい
で、各混液を表１に示す条件で加熱して共沈させたが、
このとき各混液ともほぼpHは８であつた。When nitric acid solution was added to the urea solutions to make mixed solutions, the pH of each mixed solution was about 1.6. Then, each mixed solution was heated under the conditions shown in Table 1 to coprecipitate.
At this time, the pH of each mixed solution was about 8.
各混液を吸引過（紙5C）に共沈物を分別し、70
℃、24時間乾燥した。得られた各乾燥物はフワフワした
微粉末であつた。Separate each mixture into aspirator (paper 5C) to separate coprecipitate, and
It was dried at ℃ for 24 hours. Each of the obtained dried products was a fluffy fine powder.
各乾燥物は600℃、１時間（ただし、実施例８のみは
２時間）電気炉で仮焼してペロブスカイト型酸化物を製
造した。製造された各試料とも54.1gであり、微粉末状
態であつた。Each dried material was calcined in an electric furnace at 600 ° C. for 1 hour (however, only in Example 8 for 2 hours) to produce a perovskite type oxide. Each manufactured sample weighed 54.1 g and was in a fine powder state.
各酸化物微粉末の平均粒径は自然沈降式粒度測定機で
調べ、その結果を表１に併記した。また鉱物組成につい
てＸ線回折計で調べたところ全試料ともPbZr0.52Ti0.43
O3の単一鉱物であつた。The average particle size of each oxide fine powder was examined by a natural sedimentation type particle sizer, and the results are also shown in Table 1. When the mineral composition was examined by an X-ray diffractometer, PbZr 0.52 Ti 0.43 was found for all samples.
It was a single mineral of O 3 .
〔発明の効果〕 本発明は金属水酸化物の共沈物をつくるのに、尿素を
採用したので、仮焼物は従来法のように団塊にならず、
サブミクロンの微粉末を粉砕工程を経ずして製造でき、
その分不純物の混入の少ないペロブスカイト型酸化物微
粉末が得られる。 EFFECTS OF THE INVENTION Since the present invention employs urea to form a coprecipitate of metal hydroxide, the calcined product does not become a nodule unlike the conventional method,
Submicron fine powder can be manufactured without going through the crushing process,
As a result, fine perovskite oxide powder containing less impurities can be obtained.
Claims (1)
と、製造されるペロブスカイト型酸化物１モルに対し、
３モル以上の尿素を溶解させた水溶液とをPH2以下に保
ちつつ混合し、次いで該混液を攪拌しながら50〜105℃
に加熱して共沈物を生成させたのち、該共沈物を乾燥
し、仮焼することを特徴とする一般式PbZrXTi1-XO3で表
わされるペロブスカイト型酸化物微粉末の製造方法。1. A nitric acid solution containing metal ions of Pb, Zr and Ti, and 1 mol of a perovskite type oxide produced.
Mixing with an aqueous solution in which 3 mol or more of urea is dissolved while keeping it at PH2 or less, and then stirring the mixed solution at 50 to 105 ° C.
To produce a coprecipitate, which is then dried and calcined to produce a perovskite oxide fine powder represented by the general formula PbZr X Ti 1-X O 3. Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055291A JP2547007B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing perovskite type oxide fine powder |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62055291A JP2547007B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing perovskite type oxide fine powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63222014A JPS63222014A (en) | 1988-09-14 |
| JP2547007B2 true JP2547007B2 (en) | 1996-10-23 |
Family
ID=12994476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62055291A Expired - Lifetime JP2547007B2 (en) | 1987-03-12 | 1987-03-12 | Method for producing perovskite type oxide fine powder |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2547007B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5275759A (en) * | 1989-02-10 | 1994-01-04 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Zirconia sol, method for production thereof, porous ceramic-producing slurry, and porous ceramic product obtained by use thereof |
| WO1990009350A1 (en) * | 1989-02-10 | 1990-08-23 | Nippon Shokubai Kagaku Kogyo Co., Ltd. | Zirconia sol, preparation thereof, slurry for use in the production of porous ceramic, and porous ceramic produced from said slurry |
| EP1227139B1 (en) * | 2001-01-24 | 2006-04-05 | Ahmet Cüneyt Prof. Dr. Tas | Method of producing crystalline phosphor powders at low temperature |
| KR100527060B1 (en) * | 2001-04-06 | 2005-11-08 | (주)아해 | Preparation of Single and Multi-Component Oxide by Pyrophoric Synthesis Method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61215218A (en) * | 1985-03-19 | 1986-09-25 | Agency Of Ind Science & Technol | Production of functional oxide powder |
-
1987
- 1987-03-12 JP JP62055291A patent/JP2547007B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63222014A (en) | 1988-09-14 |
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