JPS60137870A - Zirconia sintered body - Google Patents

Abstract

(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

【発明の詳細な説明】 本発明は高強度に優れ、かつ熱的安定性の高いジルコニ
ア焼結体の改良に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a zirconia sintered body having excellent high strength and high thermal stability.

カルシウム、マグネシウム、イツトリウム、チタニウム
およびセリウムの可溶性塩類又は酸化物の中から選ばれ
た少なくとも１種の第１成分とビスマス、銅、スズ、ア
ルミニウムおよび鉄の可溶性塩類又は酸化物の中から選
ばれた少なくとも１種の第２成分とを溶解した水溶性ジ
ルコニウム塩の水溶液中にアンモニア水を加えて得た沈
殿物を原料粉として成形、焼成して高密度ジルコニア焼
結体を得る方法が特公昭５４−２５５２３号公報により
知られている。At least one first component selected from soluble salts or oxides of calcium, magnesium, yttrium, titanium, and cerium and soluble salts or oxides selected from bismuth, copper, tin, aluminum, and iron. A method of obtaining a high-density zirconia sintered body by forming and firing a precipitate obtained by adding aqueous ammonia into an aqueous solution of a water-soluble zirconium salt containing at least one second component as a raw material powder was published in 1973. It is known from the publication No.-25523.

上記の方法によオｔば完全安定化ジルコニア焼結体や高
強度の部分安定化ジルコニア焼結体が比較的容易に製造
できるとされているが、再現性の良い高強度の部分安定
化ジルコニア焼結体を得るためには、焼結体に含まれる
正方晶結晶の粒径を１μｍ以下望ましくは０．５μｍ以
下にしなければならず、焼成温度は焼結に必要な最低に
近い温屁で焼成し焼成中における結晶成長をできるだけ
少なくしなければならない。従って常圧焼成においては
１５５０℃以下望ましくは１５００℃以下で焼成する必
要がある。しかし仁のような低い温度で焼成して前記原
料粉を焼結させるだめにはビスマス、銅、スズ等の焼結
助剤を添加する必要があるが、このような焼結助剤は結
晶成長を助長する性質を有するため添加量の精密な制御
および分布を均一化させる分散が必要であり、焼成温度
分布もより正確に制御しなければならない。このように
高強度の部分安定化ジルコニア焼結体を得るには高度の
セラミック製造技術が必要で多大の困難を伴う。It is said that fully stabilized zirconia sintered bodies and high-strength partially stabilized zirconia sintered bodies can be produced relatively easily by the above method, but high-strength partially stabilized zirconia sintered bodies with good reproducibility In order to obtain a sintered body, the grain size of the tetragonal crystals contained in the sintered body must be 1 μm or less, preferably 0.5 μm or less, and the firing temperature must be close to the lowest temperature required for sintering. Crystal growth during firing must be minimized. Therefore, in normal pressure firing, it is necessary to perform the firing at a temperature of 1550°C or lower, preferably 1500°C or lower. However, in order to sinter the raw material powder by firing at a low temperature such as kerosene, it is necessary to add sintering aids such as bismuth, copper, and tin. Because it has the property of promoting , it is necessary to precisely control the amount added and to disperse it to make the distribution uniform, and the firing temperature distribution must also be controlled more precisely. Obtaining a partially stabilized zirconia sintered body with such high strength requires advanced ceramic manufacturing technology and is accompanied by great difficulties.

本発明はかかる欠点のないジルコニア焼結体を提供する
ことを目的とするものである。The object of the present invention is to provide a zirconia sintered body free from such drawbacks.

本発明者らは上記の欠点について化学組成等を変えジル
コニア焼結体の性能の調査研究を進めた結果、酸化ジル
コニウムを７６〜９８モルチ、モルイツトリウムを０．
５〜４．０モル係および酸化セリウムを０．５〜２０．
０モル係含有させたところ。The present inventors investigated the performance of zirconia sintered bodies by changing the chemical composition to address the above-mentioned drawbacks, and as a result, they found that zirconium oxide was used at 76 to 98 mol, and mol ythrium was added at 0.
5 to 4.0 molar ratio and 0.5 to 20.0 molar ratio of cerium oxide.
When it was made to contain 0 molar ratio.

正方晶結晶の粒子径が１μｍを越えても機械的強度のば
らつき、低下等は生ぜず常に高い機械的強度を示すこと
を確認した。また結晶を成長させ。It was confirmed that even when the particle size of the tetragonal crystal exceeds 1 μm, no variation or decrease in mechanical strength occurs, and high mechanical strength is always exhibited. Grow crystals again.

“かつ高温における熱変形に悪影響を与える焼結助剤を
添加することなく　、１５００℃程度の温度でも焼結し
９反面焼成温匿が１６００℃、１６５０℃と高くなり焼
結体内の正方晶結晶が１〜３μｍとと大きく成長しても
その高強度は持続すると共に。“Also, it can be sintered at temperatures of around 1,500°C without adding sintering aids that adversely affect thermal deformation at high temperatures.9 On the other hand, the sintering temperature is as high as 1,600°C and 1,650°C, resulting in tetragonal crystals within the sintered body. Even when it grows to a size of 1 to 3 μm, its high strength remains.

結晶は熱的にも安定で焼成後の冷却途中で正方晶から単
斜晶に変化することがないことも確認した。It was also confirmed that the crystals were thermally stable and did not change from tetragonal to monoclinic during cooling after firing.

本発明は酸化ジルコニウム７６〜９８モルチ。The present invention uses 76 to 98 moles of zirconium oxide.

酸化イツトリウム０．５〜４，０モル係および酸化セリ
ウム０．５〜２０．０モル係を含有してなるジルコニア
焼結体に関する。The present invention relates to a zirconia sintered body containing 0.5 to 4.0 moles of yttrium oxide and 0.5 to 20.0 moles of cerium oxide.

なお本発明において酸化ジルコニウムは７６〜９８モル
チのモルとされ、酸化セリウムは０．５〜２０．０モル
係の範囲とされるが、酸化ジルコニウムが９８モル係を
越え酸化セリウムが０．５モル係未満であると焼結体の
熱的安定性が劣り、酸化ジルコニウムが７６モモル係満
とされ、酸化セリウムが２０．０モル係を越えると焼結
体の機械的強度が低くなる。In the present invention, zirconium oxide has a mole of 76 to 98 mole, and cerium oxide has a mole of 0.5 to 20.0 mole, but if zirconium oxide exceeds 98 mole, cerium oxide has a mole of 0.5 mole. If the zirconium oxide content is less than 76 molar ratio, the thermal stability of the sintered body will be poor, and if the cerium oxide content exceeds 20.0 molar ratio, the mechanical strength of the sintered body will be low.

また酸化イツトリウムは、０゜５〜４．０モル係の範囲
とされ、この範囲から外れると焼結体の機械的強度が低
くなる。Further, yttrium oxide has a molar ratio of 0.5 to 4.0, and if it deviates from this range, the mechanical strength of the sintered body decreases.

本発明におけるジルコニア焼結体の化学組成は上記の範
囲とされるが、酸化イツトリウムを１〜３モルモル酸化
セリウム’ｉｏ、５〜８モルモルし残りを酸化ジルコニ
ウムとすれば、　１２０　Ｋｇ／ｗｎ”以上の高張式の
ジルコニア焼結体が得られるので好ましい。この組成の
場合は２００〜５００℃で１０００時間以上の長時間使
用すると結晶が次第に変化するので室温使用に適した構
造材となる。The chemical composition of the zirconia sintered body in the present invention is within the above range, but if 1 to 3 mol mol of yttrium oxide is cerium oxide, 5 to 8 mol mol, and the remainder is zirconium oxide, the chemical composition is 120 Kg/wn" or more. This composition is preferred because it yields a hypertonic zirconia sintered body. With this composition, the crystals gradually change when used for a long time of 1000 hours or more at 200 to 500°C, making it a structural material suitable for use at room temperature.

これに対し酸化セリウムの量が８モル係を越えると曲げ
強さは’２０４／Ｉｍ２以上にはならないが。On the other hand, if the amount of cerium oxide exceeds 8 molar ratio, the bending strength will not exceed '204/Im2.

長時間高温で使用しても結晶は変化しないので得られる
焼結体は、畠温断熱構造材に適する。Since the crystals do not change even when used at high temperatures for long periods of time, the obtained sintered body is suitable for Hatatetsu insulation structural materials.

さらに本発明ではジルコニア焼結体が立方晶を含む正方
品結晶ｆｆ：８０ｆｆｉ量１以上（単斜晶結晶を２０重
ｆ％未満）含有し、０〜８００℃における平均熱膨張係
数が９Ｘ１０−’／’Ｃ以上でめれは強度の安定性に優
れると共に焼結体内部の結晶組織が熱的に安定であるの
で好ましい。Furthermore, in the present invention, the zirconia sintered body contains tetragonal crystals including cubic crystals ff:80ffi in an amount of 1 or more (monoclinic crystals less than 20% by weight), and has an average thermal expansion coefficient of 9X10-' at 0 to 800°C. /'C or more is preferable because it provides excellent strength stability and the crystal structure inside the sintered body is thermally stable.

以下実施例により本発明を説明する。The present invention will be explained below with reference to Examples.

実施例 炭ｔジルコニウム粉（マグネシウムエレクトロン社製）
、酸化イツ）　ＩＪウム粉（信越化学課、純度９９．５
％）および酸化セリウム粉（信越化学膜。Example carbon t zirconium powder (manufactured by Magnesium Electron)
, oxide) IJum powder (Shin-Etsu Chemical Division, purity 99.5
%) and cerium oxide powder (Shin-Etsu Chemical Membrane).

純度９９．５％）を第１表に示す配合割合に秤量しＩＮ
の塩酸に溶解し１次いで溶解物を攪拌しながらアンモニ
ア水を滴下し中和して沈殿物を得た。(purity 99.5%) was weighed to the proportions shown in Table 1 and IN
The solution was dissolved in hydrochloric acid, and then aqueous ammonia was added dropwise to the solution while stirring to neutralize it to obtain a precipitate.

次に沈殿物をろ過し、残渣にエチルアルコールを添加し
減圧乾燥後８００℃で加熱処理をした。Next, the precipitate was filtered, ethyl alcohol was added to the residue, and after drying under reduced pressure, it was heated at 800°C.

その後樹脂製ポットおよび玉石を使用し、２４時霧乾燥
法で造粒して成形粉を得１．さらに前記の成形粉を１ト
ン／ｃｍ　”の圧力にて加圧成形し、６×５×６０１１
ＩＩ１１の成形体を得た。次にこの成形体を１６００℃
の温度で焼成してジルコニア焼結体を得た。Thereafter, using a resin pot and cobblestones, granulation was carried out using a 24-hour fog drying method to obtain molded powder.1. Furthermore, the above-mentioned molding powder was pressure-molded at a pressure of 1 ton/cm 2 to form a 6×5×6011
A molded product II11 was obtained. Next, this molded body was heated to 1600°C.
A zirconia sintered body was obtained by firing at a temperature of .

次に前記のジルコニア焼結体をダイアモンド砥石（２０
０番）ｔ−使用して四面研削し、さらにターイアモンド
ペーストで鏡面仕上けして４Ｘ３Ｘ４０ｍｍの試料を得
た。この試料を用いて各種試験を行なった。なお試験条
件において試料に含まれる結晶址の測定は焼成表面、ダ
イアモンド研削面および加熱処理した試料の表面をＸ線
回折装置を使用し、単斜晶、正方晶、立方晶結晶の回折
ピーク強度から含有率を算出した。その測定結果を合わ
せてＩ；ｌ！１表に示す。なお立方晶と正方晶の回折ピ
ークの分離は困ＭＬであるためその含量で算出した。ま
た曲は強さは３点曲げ試験法で行ない、熱的安定性は５
Ｘ１０Ｘ１００ｍｍの成形体を製作し。Next, the zirconia sintered body was placed on a diamond whetstone (20
No. 0) T- was used to grind all sides, and the sample was mirror-finished with diamond paste to obtain a sample of 4 x 3 x 40 mm. Various tests were conducted using this sample. The crystal mass contained in the sample was measured under the test conditions by using an X-ray diffraction device on the fired surface, diamond-ground surface, and heat-treated surface of the sample, and from the diffraction peak intensities of monoclinic, tetragonal, and cubic crystals. The content rate was calculated. Combined with the measurement results, I;l! It is shown in Table 1. In addition, since it is difficult to separate the diffraction peaks of cubic and tetragonal crystals, calculations were made based on their contents. In addition, the strength of the song was tested using the 3-point bending test method, and the thermal stability was tested at 5.
Produced a molded body of X10X100mm.

その成形体の一端’（ｉ−１２００℃に加熱し、他の一
端は２５℃に設置して試料に温展勾配を与えて劣化状況
を調べだ。One end of the molded body was heated to 1200°C (i-1200°C), and the other end was placed at 25°C to apply a warming gradient to the sample to examine its deterioration status.

以下余白 第１表から酸化ジルコニウムに、酸化イツトリウムと酸
化セリウムを併用したものはいずれか一方のみを添加し
た場合に比較し、得られる焼結体の機械的強度が高く、
また熱的安定性も高いことがわかる。From Table 1 in the margin below, when zirconium oxide is combined with yttrium oxide and cerium oxide, the mechanical strength of the resulting sintered body is higher than when only one of them is added.
It can also be seen that the thermal stability is high.

本発明によれば常に高い機械的強度を示し、また熱的安
定性も旨いので、室温から高温の使用に適した断熱構造
材に適したジルコニア焼結体を得ることができる。According to the present invention, a zirconia sintered body that consistently exhibits high mechanical strength and good thermal stability can be obtained, which is suitable for use as a heat insulating structural material suitable for use at room temperatures to high temperatures.

Claims (1)

【特許請求の範囲】 １、酸化ジルコニウム７６〜９８モルチ、酸化イツトリ
ウム０．５〜４．０モルチおよび酸化セリウム０．５〜
２０．０モルチを含有してなるジルコニア焼結体。 ２、　ジルコニア焼結体が立方晶を含む正方晶結晶を８
０重ｆｆ１１以上（単斜晶結晶を２０重量％未＃）含有
し、０〜８００℃における平均熱膨張係数が９　Ｘ　１
０−６／℃以上である特許請求の範囲第１項記載のジル
コニア焼結体。[Claims] 1. Zirconium oxide 76 to 98 molti, yttrium oxide 0.5 to 4.0 molti, and cerium oxide 0.5 to 98 molti
A zirconia sintered body containing 20.0 molti. 2. The zirconia sintered body has 8 tetragonal crystals including cubic crystals.
Contains 0 weight ff11 or more (20 weight% monoclinic crystals), and has an average thermal expansion coefficient of 9 x 1 at 0 to 800°C
The zirconia sintered body according to claim 1, which has a temperature of 0-6/°C or higher.