JPS6121185B2 - - Google Patents
Info
- Publication number
- JPS6121185B2 JPS6121185B2 JP56020833A JP2083381A JPS6121185B2 JP S6121185 B2 JPS6121185 B2 JP S6121185B2 JP 56020833 A JP56020833 A JP 56020833A JP 2083381 A JP2083381 A JP 2083381A JP S6121185 B2 JPS6121185 B2 JP S6121185B2
- Authority
- JP
- Japan
- Prior art keywords
- porcelain
- crystal grains
- zirconium oxide
- tetragonal
- temperature
- 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
Links
- 239000013078 crystal Substances 0.000 claims description 61
- 229910052573 porcelain Inorganic materials 0.000 claims description 41
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 claims description 32
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 claims description 30
- RVTZCBVAJQQJTK-UHFFFAOYSA-N oxygen(2-);zirconium(4+) Chemical compound [O-2].[O-2].[Zr+4] RVTZCBVAJQQJTK-UHFFFAOYSA-N 0.000 claims description 26
- 229910001928 zirconium oxide Inorganic materials 0.000 claims description 26
- 238000004519 manufacturing process Methods 0.000 claims description 11
- -1 yttrium compound Chemical class 0.000 claims description 10
- 229910052727 yttrium Inorganic materials 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 2
- 238000010304 firing Methods 0.000 description 12
- 230000006866 deterioration Effects 0.000 description 11
- 239000012071 phase Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 9
- 238000005452 bending Methods 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 238000010438 heat treatment Methods 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 238000005245 sintering Methods 0.000 description 6
- 238000002441 X-ray diffraction Methods 0.000 description 5
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 5
- 229910002077 partially stabilized zirconia Inorganic materials 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 239000007784 solid electrolyte Substances 0.000 description 4
- 230000032683 aging Effects 0.000 description 3
- 229910002078 fully stabilized zirconia Inorganic materials 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 239000003381 stabilizer Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 239000003779 heat-resistant material Substances 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 150000003748 yttrium compounds Chemical class 0.000 description 2
- OERNJTNJEZOPIA-UHFFFAOYSA-N zirconium nitrate Chemical compound [Zr+4].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O OERNJTNJEZOPIA-UHFFFAOYSA-N 0.000 description 2
- OBOSXEWFRARQPU-UHFFFAOYSA-N 2-n,2-n-dimethylpyridine-2,5-diamine Chemical compound CN(C)C1=CC=C(N)C=N1 OBOSXEWFRARQPU-UHFFFAOYSA-N 0.000 description 1
- NGDQQLAVJWUYSF-UHFFFAOYSA-N 4-methyl-2-phenyl-1,3-thiazole-5-sulfonyl chloride Chemical compound S1C(S(Cl)(=O)=O)=C(C)N=C1C1=CC=CC=C1 NGDQQLAVJWUYSF-UHFFFAOYSA-N 0.000 description 1
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- 229910017493 Nd 2 O 3 Inorganic materials 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000002250 absorbent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 238000000975 co-precipitation Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000008240 homogeneous mixture Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- IBSDADOZMZEYKD-UHFFFAOYSA-H oxalate;yttrium(3+) Chemical compound [Y+3].[Y+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O IBSDADOZMZEYKD-UHFFFAOYSA-H 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229910052761 rare earth metal Inorganic materials 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 150000003755 zirconium compounds Chemical class 0.000 description 1
- DUNKXUFBGCUVQW-UHFFFAOYSA-J zirconium tetrachloride Chemical group Cl[Zr](Cl)(Cl)Cl DUNKXUFBGCUVQW-UHFFFAOYSA-J 0.000 description 1
- 229910021489 α-quartz Inorganic materials 0.000 description 1
Description
本発明は高強度でかつ特定温度領域における長
時間使用による経時劣化の極めて少ないZrO2−
Y2O3系のジルコニア磁器の製造法に関するもの
である。
従来、ZrO2−Y2O3系のジルコニア磁器の製造
法としては、立方晶のみより成る完全安定化ジル
コニア磁器の製造法と、立方晶と単斜晶より成る
部分安定化ジルコニア磁器の製造法が知られてお
り、これらの製造法によつて得られるジルコニア
磁器はいずれも耐熱材料、固体電解質等として使
用されている。このうち完全安定化ジルコニア磁
器は、常温から約1500℃迄の温度範囲において安
定であり長時間使用による経時劣化もほとんど無
いものであるが、反面強度が低いので例えば自動
車排ガス中の酸素濃度を検出する酸素センサー用
固体電解質として利用した場合、熱衝撃によつて
極めて破損しやすいという欠点があつた。一方立
方晶と単斜晶よりなる部分安定化ジルコニア磁器
は完全安定化ジルコニア磁器に較べると強度は大
きく耐熱衝撃性もよいものであるが、200℃ない
し300℃という特定温度域における強度の経時劣
化が極めて大きく、該温度で長時間使用した場
合、磁器表面に微細なクラツクが多数発生して吸
水性を示すようになり著しく強度が低下し、つい
には破損するという重大な欠点を有しているもの
であつた。
これはZrO2−Y2O3系部分安定化ジルコニア磁
器では約1500℃の焼成温度において正方晶である
結晶粒子が約1500℃から室温への冷却中に500℃
付近で単斜晶に相変態を起こし、その際生ずる体
積変化により磁器中に過大な応力が加わりそのた
め極めて微小なクラツクが結晶粒子内に多数発生
し、このクラツクが200℃ないし300℃の特定温度
領域に長時間おかれると拡大しやがて磁器破壊に
至るものであると考えられる。
さらに、立方晶と単斜晶より成る部分安定化ジ
ルコニア磁器は室温から約800℃の間で加熱冷却
を繰り返すと500℃付近で起る単斜晶と正方晶と
の相変態により熱膨脹曲線が加熱方向と冷却方向
で異なるいわゆるヒステリシス曲線となり、かつ
室温にもどしたときの寸法が加熱冷却の前後で異
なるので高精度の寸法が維持できない欠点があつ
た。
本発明は、従来のこのような部分安定化ジルコ
ニア磁器の欠点を解消し、優れた強度を有すると
ともに200℃ないし300℃の特定温度域における強
度の経時劣化を著しく改良し、かつ室温から約
800℃までの熱膨脹曲線に相変態によるヒステリ
シス現象がなく、室温における高い寸法精度を維
持できるジルコニア磁器の製造法であり、結晶子
径が1000Å以下の酸化ジルコニウム又は無定形酸
化ジルコニウム特に好ましくは、水酸化ジルコニ
ルを熱分解して得た酸化ジルコニウムとイツトリ
ウム化合物より成りY2O3／ZrO2のモル比が２／
98〜７／93の範囲である混合物の成形体、好まし
くはその混合物を200〜1200℃の温範囲内で熱分
解し、解砕した後成形した成形体を、1000〜1550
℃の温度範囲で焼成して、主として正方晶の結晶
粒子、または正方晶の結晶粒子と立方晶の結晶粒
子とより成りかつ平均結晶粒子径が２μ以下で、
200℃ないし300℃における耐久性に優れたジルコ
ニア磁器を製造する磁器の製造法である。
すなわち、本発明は200〜300℃の特定温度域に
おける強度の経時劣化が極めて少なく、かつ室温
〜800℃の温度域での加熱冷却による寸法変化の
ないジルコニア磁器としては、Y2O3／ZrO2のモ
ル比が２／98〜７／93であり、各々の結晶粒子の
結晶相が主として正方晶の結晶粒子、または正方
晶の結晶粒子と立方晶の結晶粒子とより成りかつ
平均結晶粒子径が２μ以下である、すなわち
Y2O3／ZrO2モル比、結晶粒子の結晶相、平均結
晶粒子径という３要件のいずれも満たすことが大
切であることを究明し、そのためには成形体を構
成する酸化ジルコニウムの結晶子径が特定粒径以
下または無定形であることが最も重要であるとと
もに、安定化剤の量および焼成温度等が特定範囲
内であることが必要であることを幾多の研究の結
果究明したことにもとづくものである。
本発明を以下に詳しく説明する。
本発明において200℃ないし300℃における耐久
性に優れていると称するは200℃ないし300℃の間
の任意の温度において経時劣化が少ないことを意
味する。具体的な測定手段の一例としては実施例
で述べるように大気中で200℃ないし300℃の間を
10℃／分の昇降温速度で加熱冷却を繰り返す耐久
試験を行い、耐久前と耐久後の抗折強度の変化を
測定するのが良い。耐久時間は長い程劣化の程度
が増大するが、1500時間程度で従来のジルコニア
磁器と本発明によつて得られるジルコニア磁器と
の差が明瞭となる。
焼結後のジルコニア磁器が、主として正方晶の
結晶粒子、または正方晶の結晶粒子と立方晶の結
晶粒子とより安定的に成るためには、前述のとお
り成形体を構成する酸化ジルコニウムは特定結晶
子径すなわち1000Å以下又は無定形、好ましくは
結晶子径が700Å〜300Åであることがよい。
すなわち成形体を構成する酸化ジルコニウムの
結晶子径とジルコニア磁器の結晶相との関係をＸ
線回折強度比で表わすと、例えば第１図および第
２図に示すとおり、結晶子径が700Å以下の範囲
または無定形では主として正方晶の結晶粒子（Ｈ
領域）、または正方晶の結晶粒子と立方晶の結晶
粒子（H′領域）とより成つており、700〜1000Å
の範囲ではこれらにわずかに単斜晶の結晶粒子が
混入する程度（Ｉ領域）であるが1000Åを超える
と急激に単斜晶の結晶粒子が増加する（Ｊ領
域）。
なお、結晶子径が０μとは無定形の酸化ジルコ
ニウムであることを示す。ただし無定形の酸化ジ
ルコニウムを用いる場合は焼成収縮が過大となる
ため、好ましくは結晶の酸化ジルコニウムがよ
い。ここで第１図および第２図中、Ｔ（200）、Ｃ
（200）、Ｍ（11１）はそれぞれ正方晶の（200）
面、立方晶の（200）面、単斜晶の（11１）面の
Ｘ線回折線強度を示す。
従つて、ジルコニア磁器の結晶相を経時劣化の
少ない主として正方晶の結晶粒子、または正方晶
の結晶粒子と立方晶の結晶粒子とに安定的に維持
するためには、成形体を構成する酸化ジルコニウ
ムは結晶子経が1000Å以下または無定形でなけれ
ばならないことが第１図および第２図よりも明確
である。ここで重要なことは特定の結晶子経をも
つ酸化ジルコニウムは酸化イツトリウム等の安定
化剤と固溶していないことである。固溶していな
い原料を用いると焼成時に酸化ジルコニウムと安
定化剤が反応焼結を起こす。原料の段階で固溶し
ていると単なる固相焼結となる。特に本発明の磁
器の場合、反応焼結を起こすと固相焼結より焼成
温度下げることができ、磁器の粒成長を抑制し、
結果としてより正方晶の結晶粒子が安定し、200
℃〜300℃での耐久性が良好となる。ここで、原
料調製時に例えばジルコニウム化合物とイツトリ
ウム化合物との混合溶液から共沈によつて酸化ジ
ルコニウムと酸化イツトリウムとした原料であつ
ても、酸化ジルコニウムと酸化イツトリウムが固
溶していなければ差しつかえない。
なお、結晶子経が1000Å以下または無定形の酸
化ジルコニウムは塩化ジルコニウム、硝酸ジルコ
ニウム等の熱分解等でも得られるが、好ましくは
水酸化ジルコニル（ZrO（OH）2・nH2O）を200
〜1100℃の温度より好ましくは500〜1050℃の温
度で熱分解した酸化ジルコニウム粉末がよい。こ
の場合水酸化ジルコニルの熱分解温度が200℃未
満では水酸化ジルコニル中の水が完全に取れず、
また1100℃を越えると結晶子経は1000Åを超える
ので好ましくない。
本発明の製造法においてはまず、酸化ジルコニ
ウムとイツトリウム化合物をY2O3／ZrO2のモル
比が２／98〜７／93の範囲内となるように混合す
る。この場合酸化ジルコニウムとイツトリウム化
合物との混合比がY2O3／ZrO2のモル比に換算し
て２／98〜７／93の範囲内であることが、経時劣
化改善のために極めて重要である。これは２／98
未満では経時劣化改善のための正方晶の結晶粒子
の生成が無く、また７／93を越えても正方晶の結
晶粒子がほとんど含まれなくなり立方晶の結晶粒
子のジルコニア磁器となるからである。
また、イツトリウム化合物としては酸化イツト
リウム、塩化イツトリウム、硝酸イツトリウム、
蓚酸イツトリウム等が好ましく、この場合イツト
リウム化合物としては、酸化物に換算して約30モ
ル％以下の例えばYb2O3、Sc2O3、Nd2O3、
Sm2O3等の稀土類元素酸化物あるいはCaO、
MgO等で置換したものでもよい。次いで、混合
物をラバープレス成形、押出成形、鋳込成形等の
成形法により所定の形状に成形し、空気中で1000
〜1550℃の温度範囲内で焼成する。焼成は1000〜
1550℃の温度好ましくは1100〜1450℃の温度範囲
内で最高温度で１〜20時間保持する。焼成時間は
一般に低温焼成のときほど長くする方がよい。な
お、焼成温度と磁器の結晶相との関係は、焼成温
度が1000℃末満あるいは1550℃を越えると急激に
単斜晶の生成が増大するので好ましくなく、1000
〜1550℃の温度範囲内であれば主として正方晶ま
たは正方晶と立方晶の混合相が安定的に生成す
る。更にY2O3／ZrO2のモル比が好ましくは４／
96〜７／93の範囲では主として正方晶と立方晶よ
り成る磁器が得られ酸素イオン導電性が高く200
〜300℃における経時劣化が少なく固体電解質と
して好適である。
なお、酸化ジルコニウムとイツトリウム化合物
との混合物を200〜1200℃の温度で１〜10時間程
度加熱することによりイツトリウム化合物を熱分
解して、さらに必要に応じてボールミル等で解砕
したものに原料として使用すると酸化ジルコニウ
ムと酸化イツトリウムの均一な混合物が得られ、
これを成形し焼成するとより緻密な磁器ができ好
ましいものである。ボールミル等による解砕後の
原料粒度は0.1〜10μ程度である。
また、酸化ジルコニウムとイツトリウム化合物
の混合物に焼結助剤としてSiO2、Al2O3、粘土等
を磁器全体の30重量％以下添加してもよい。
なお、本発明において酸化ジルコニウムの結晶
子経はCuKα線を用いたＸ線回折法で行ない、
式Ｄ＝0.89λ／（Ｂ−ｂ）cosθにより求めた。
ここでＤは求める酸化ジルコニウムの結晶子経、
λはCuKα線の波長で1.541Å、Ｂは酸化ジルコ
ニウムの単斜晶（11１）面または正方晶（111）
面の回折線の半減値幅（ラジアン）のうち大きい
方の値、ｂは内部標準として添加する結晶子経の
3000Å以上のα−石英の（101）面の半減値幅
（ラジアン）、θは酸化ジルコニウムの半減値幅の
測定に用いた回折線の回折角２θの1/2の値であ
る。
次に実施例を述べる。
第１表に示すように酸化ジルコニウムとイツト
リウム化合物を表中の組成となるようにボールミ
ル混合した。そしてその混合物を表中に熱分解の
記載のあるものはその条件で熱分解を行なつてか
ら焼結助剤を加えてボールミルにて湿式粉砕し、
乾燥した後それぞれの粉末をプレス成形し、第１
表記載の温度条件で焼成した。そして得られた磁
器について平均結晶粒子径およびＸ線回折線によ
る正方晶、立方晶、単斜晶の強度比および抗折強
度を測定した。なお結晶子経は成形体とする混合
物を用いて測定し、磁器のＸ線回折線強度比の測
定は磁器の鏡面研磨面を用いて行ない立方晶の
（200）面、正方晶の（200）面および単斜晶の
（11１）面でのＸ線回折線ピーク強度の比を求め
た。また抗折強度は3.5×3.5×50mmの棒状に仕上
げ３点曲げ法にて求めた。また第１表中の耐久試
験とは200〜300℃の間を10℃／分の昇降温速度で
加熱、冷却を繰り返した耐久試験であり、1500時
間経過後、抗折強度を測定した。さらに耐久試験
前の抗折強度に対する耐久試験後の抗折強度の割
合をパーセントで示した。
なお第１表には本発明の数値限定範囲外の例を
参考例として合せ記載した。
The present invention is a ZrO 2
This invention relates to a method for producing Y 2 O 3 based zirconia porcelain. Conventionally, methods for producing ZrO 2 −Y 2 O 3 system zirconia porcelain include a method for producing fully stabilized zirconia porcelain consisting only of cubic crystals, and a method for producing partially stabilized zirconia porcelain consisting of cubic crystals and monoclinic crystals. are known, and zirconia porcelain obtained by these manufacturing methods are all used as heat-resistant materials, solid electrolytes, etc. Of these, fully stabilized zirconia porcelain is stable in the temperature range from room temperature to approximately 1,500°C and hardly deteriorates over time due to long-term use.However, on the other hand, its strength is low, so it can be used, for example, to detect oxygen concentration in automobile exhaust gas. When used as a solid electrolyte for oxygen sensors, it has the disadvantage of being extremely susceptible to damage due to thermal shock. On the other hand, partially stabilized zirconia porcelain made of cubic and monoclinic crystals has higher strength and better thermal shock resistance than fully stabilized zirconia porcelain, but its strength deteriorates over time in a specific temperature range of 200°C to 300°C. is extremely large, and when used for a long time at such temperatures, it has the serious drawback that many minute cracks occur on the porcelain surface, it becomes water-absorbent, its strength decreases significantly, and it eventually breaks. It was hot. This is because in ZrO 2 −Y 2 O 3 system partially stabilized zirconia porcelain, the crystal grains, which are tetragonal at a firing temperature of about 1500°C, are heated to 500°C during cooling from about 1500°C to room temperature.
A phase transformation to monoclinic occurs in the vicinity, and the volume change that occurs at this time applies excessive stress to the porcelain, resulting in many extremely small cracks within the crystal grains, and these cracks occur at a specific temperature of 200°C to 300°C. It is thought that if left in the area for a long time, it will expand and eventually lead to porcelain destruction. Furthermore, when partially stabilized zirconia porcelain consisting of cubic and monoclinic crystals is repeatedly heated and cooled from room temperature to approximately 800°C, the thermal expansion curve becomes heated due to the phase transformation between monoclinic and tetragonal crystals that occurs around 500°C. The so-called hysteresis curves are different in the direction and the cooling direction, and the dimensions when returned to room temperature are different before and after heating and cooling, so there is a drawback that highly accurate dimensions cannot be maintained. The present invention eliminates the drawbacks of conventional partially stabilized zirconia porcelain, has excellent strength, significantly improves the aging deterioration of strength in a specific temperature range of 200°C to 300°C, and improves strength from room temperature to approximately
This is a method for producing zirconia porcelain that has no hysteresis phenomenon due to phase transformation in its thermal expansion curve up to 800°C and can maintain high dimensional accuracy at room temperature. It is made of zirconium oxide obtained by thermally decomposing zirconyl oxide and a yttrium compound, and the molar ratio of Y 2 O 3 /ZrO 2 is 2/
A molded body of a mixture having a temperature range of 98 to 7/93, preferably a molded body obtained by thermally decomposing the mixture within a temperature range of 200 to 1200°C, crushing it, and then molding it,
C. and is mainly composed of tetragonal crystal grains, or tetragonal crystal grains and cubic crystal grains, and has an average crystal grain size of 2 μ or less,
This is a porcelain manufacturing method that produces zirconia porcelain that has excellent durability at 200℃ to 300℃. In other words, the present invention uses Y 2 O 3 /ZrO as a zirconia porcelain that exhibits extremely little deterioration in strength over time in a specific temperature range of 200 to 300°C, and that does not change dimensions due to heating and cooling in a temperature range of room temperature to 800°C. 2 has a molar ratio of 2/98 to 7/93, the crystal phase of each crystal grain is mainly composed of tetragonal crystal grains, or tetragonal crystal grains and cubic crystal grains, and the average crystal grain size is is less than 2μ, i.e.
We determined that it is important to satisfy all three requirements: Y 2 O 3 /ZrO 2 molar ratio, crystal phase of crystal particles, and average crystal particle diameter. As a result of numerous studies, we have determined that the most important thing is that the particle diameter is below a certain particle size or that it is amorphous, and that the amount of stabilizer and firing temperature, etc., must be within a certain range. It is based on The invention will be explained in detail below. In the present invention, "excellent durability at 200°C to 300°C" means that there is little deterioration over time at any temperature between 200°C and 300°C. As an example of a specific measurement method, as described in the examples, a temperature between 200℃ and 300℃ in the atmosphere is used.
It is best to conduct a durability test in which heating and cooling are repeated at a rate of temperature rise and fall of 10°C/min, and to measure the change in bending strength before and after the test. The longer the durability time, the greater the degree of deterioration, but the difference between the conventional zirconia porcelain and the zirconia porcelain obtained by the present invention becomes clear after about 1500 hours. In order for the zirconia porcelain after sintering to be more stable with mainly tetragonal crystal grains, or with tetragonal crystal grains and cubic crystal grains, the zirconium oxide constituting the molded body must be made of specific crystals as described above. It is preferable that the crystallite diameter is 1000 Å or less or amorphous, preferably the crystallite diameter is 700 Å to 300 Å. In other words, the relationship between the crystallite diameter of zirconium oxide constituting the molded body and the crystal phase of zirconia porcelain is expressed as
When expressed as a line diffraction intensity ratio, for example, as shown in Figures 1 and 2, in the range of crystallite diameters of 700 Å or less or in amorphous form, mainly tetragonal crystal grains (H
It consists of tetragonal crystal grains and cubic crystal grains (H' region), and has a diameter of 700 to 1000 Å.
In the range , monoclinic crystal grains are slightly mixed in these (I region), but when it exceeds 1000 Å, the monoclinic crystal grains rapidly increase (J region). Note that a crystallite diameter of 0 μ indicates that the material is amorphous zirconium oxide. However, if amorphous zirconium oxide is used, the firing shrinkage will be excessive, so crystalline zirconium oxide is preferable. Here, in Figures 1 and 2, T (200), C
(200) and M(111) are respectively tetragonal (200)
The X-ray diffraction line intensities are shown for the (200) plane of the cubic crystal, and the (111) plane of the monoclinic crystal. Therefore, in order to stably maintain the crystalline phase of zirconia porcelain as mainly tetragonal crystal grains or tetragonal crystal grains and cubic crystal grains with little deterioration over time, it is necessary to It is clearer than in FIGS. 1 and 2 that the crystallite diameter must be less than 1000 Å or the crystallite size must be amorphous. What is important here is that zirconium oxide having a specific crystallite diameter is not dissolved in solid solution with a stabilizer such as yttrium oxide. If a raw material that is not in solid solution is used, zirconium oxide and the stabilizer will react and sinter during firing. If solid solution is present at the raw material stage, it will simply be solid phase sintering. In particular, in the case of the porcelain of the present invention, reactive sintering can lower the firing temperature than solid phase sintering, suppressing grain growth of the porcelain,
As a result, the tetragonal crystal grains become more stable and 200
Good durability at temperatures between ℃ and 300℃. Here, even if the raw material is made into zirconium oxide and yttrium oxide by coprecipitation from a mixed solution of a zirconium compound and a yttrium compound during raw material preparation, there is no problem as long as the zirconium oxide and yttrium oxide are not solidly dissolved. . Zirconium oxide with a crystallite diameter of 1000 Å or less or amorphous can be obtained by thermal decomposition of zirconium chloride, zirconium nitrate, etc., but preferably zirconyl hydroxide (ZrO(OH) 2 · nH 2 O) is
Zirconium oxide powder thermally decomposed at a temperature of 500 to 1050°C is more preferable than 1100°C. In this case, if the thermal decomposition temperature of zirconyl hydroxide is less than 200℃, the water in zirconyl hydroxide cannot be completely removed.
Moreover, if the temperature exceeds 1100°C, the crystallite diameter exceeds 1000 Å, which is not preferable. In the production method of the present invention, first, zirconium oxide and a yttrium compound are mixed so that the molar ratio of Y 2 O 3 /ZrO 2 falls within the range of 2/98 to 7/93. In this case, it is extremely important for the mixing ratio of zirconium oxide and yttrium compound to be within the range of 2/98 to 7/93 in terms of Y 2 O 3 /ZrO 2 molar ratio to improve aging deterioration. be. This is 2/98
If it is less than 7/93, tetragonal crystal grains will not be produced to improve aging deterioration, and if it exceeds 7/93, it will contain almost no tetragonal crystal grains and the zirconia porcelain will have cubic crystal grains. In addition, yttrium compounds include yttrium oxide, yttrium chloride, yttrium nitrate,
Yttrium oxalate is preferable, and in this case, the yttrium compound includes Yb 2 O 3 , Sc 2 O 3 , Nd 2 O 3 , etc. in an amount of about 30 mol % or less in terms of oxide.
Rare earth element oxides such as Sm 2 O 3 or CaO,
It may also be substituted with MgO or the like. Next, the mixture is molded into a predetermined shape by a molding method such as rubber press molding, extrusion molding, or casting molding, and is heated for 1000 min in air.
Firing within a temperature range of ~1550℃. Firing is 1000 ~
A temperature of 1550°C, preferably in the temperature range of 1100 to 1450°C, is maintained at maximum temperature for 1 to 20 hours. Generally, it is better to make the firing time longer when firing at a lower temperature. The relationship between the firing temperature and the crystalline phase of porcelain is unfavorable if the firing temperature is less than 1000℃ or exceeds 1550℃ because the formation of monoclinic crystals will rapidly increase.
Within the temperature range of ~1550°C, mainly tetragonal crystals or a mixed phase of tetragonal and cubic crystals are stably produced. Further, the molar ratio of Y 2 O 3 /ZrO 2 is preferably 4/
In the range of 96 to 7/93, porcelain mainly composed of tetragonal and cubic crystals is obtained, and the oxygen ion conductivity is high.
It is suitable as a solid electrolyte because it shows little deterioration over time at ~300°C. In addition, the yttrium compound is thermally decomposed by heating the mixture of zirconium oxide and the yttrium compound at a temperature of 200 to 1200°C for about 1 to 10 hours, and if necessary, the mixture is crushed using a ball mill etc. and used as a raw material. When used, a homogeneous mixture of zirconium oxide and yttrium oxide is obtained,
If this is molded and fired, a more dense porcelain can be produced, which is preferable. The particle size of the raw material after crushing using a ball mill or the like is approximately 0.1 to 10μ. Further, SiO 2 , Al 2 O 3 , clay, etc. may be added as a sintering aid to the mixture of zirconium oxide and yttrium compound in an amount of 30% by weight or less based on the total weight of the porcelain. In addition, in the present invention, the crystallite diameter of zirconium oxide is determined by an X-ray diffraction method using CuKα rays.
It was determined using the formula D=0.89λ/(B−b)cosθ.
Here, D is the desired crystallite diameter of zirconium oxide,
λ is the wavelength of the CuKα ray, which is 1.541 Å, and B is the monoclinic (111) or tetragonal (111) plane of zirconium oxide.
The larger value of the half-value width (radians) of the diffraction line of the surface, b is the crystallite diameter added as an internal standard.
The half-value width (in radians) of the (101) plane of α-quartz with a diameter of 3000 Å or more, θ is the value of 1/2 of the diffraction angle 2θ of the diffraction line used to measure the half-value width of zirconium oxide. Next, an example will be described. As shown in Table 1, zirconium oxide and yttrium compounds were mixed in a ball mill to have the compositions shown in the table. Then, if the mixture is listed as being thermally decomposed in the table, it is thermally decomposed under the conditions specified, and then a sintering aid is added and wet-pulverized in a ball mill.
After drying, each powder was press-molded and the first
It was fired under the temperature conditions listed in the table. The resulting porcelain was measured for its average crystal grain size, the intensity ratio of tetragonal, cubic, and monoclinic crystals by X-ray diffraction, and the bending strength. The crystallite diameter is measured using a mixture made into a compact, and the X-ray diffraction line intensity ratio of porcelain is measured using a mirror-polished surface of the porcelain. The ratio of the X-ray diffraction line peak intensities at the (111) plane and the (111) plane of the monoclinic crystal was determined. Further, the bending strength was determined by finishing a rod shape of 3.5 x 3.5 x 50 mm using a three-point bending method. The durability test in Table 1 was a durability test in which heating and cooling were repeated between 200 and 300°C at a rate of temperature rise and fall of 10°C/min, and the bending strength was measured after 1500 hours had elapsed. Further, the ratio of the bending strength after the durability test to the bending strength before the durability test is shown in percentage. Table 1 also lists examples outside the numerically limited range of the present invention as reference examples.
【表】【table】
【表】
第１表からも明らかなとおり本発明の製造法に
よるジルコニア磁器は、主として正方晶の結晶粒
子または正方晶の結晶粒子と立方晶の結晶粒子と
より成り平均結晶粒子径が２μ以下のきわめて高
強度で、かつ200〜300℃における耐久試験後の耐
久試験前に対する抗折強度の変化がいずれも80％
以上という経時劣化の少ない磁器であることが確
認された。
以上のべたとおり、本発明は200〜300℃の特定
温度域における経時劣化の極めて少ないジルコニ
ア磁器としてはY2O3／ZrO2モル比が２／98〜
７／93において結晶相が主として正方晶の結晶粒
子または正方晶の結晶粒子と立方晶の結晶粒子と
より成りかつ平均結晶粒子径が２μ以下であるこ
とが大切であることを見出し、そのためには成形
体を構成する酸化ジルコニウムが結晶子径1000Å
以下又は無定形でY2O3／ZrO2モル比が２／98〜
７／93でかつ焼成温度が1000〜1550℃でなければ
ならないことを究明したものであり、本発明の製
造法により特定温度域での経時劣化が少なく熱処
理による寸法変化がない機械的強度が強いジルコ
ニア磁器が製造できるものであり、それらの磁器
は例えば耐熱材料、内燃機関構部品、サーミス
タ、切削バイトおよび固体電解質等として使用で
きるものであつて、産業上極めて有用な磁器の製
造法である。[Table] As is clear from Table 1, the zirconia porcelain manufactured by the manufacturing method of the present invention is mainly composed of tetragonal crystal grains or tetragonal crystal grains and cubic crystal grains, and has an average crystal grain size of 2μ or less. Extremely high strength, with 80% change in bending strength after durability test at 200-300℃ compared to before durability test
It was confirmed that the porcelain has little deterioration over time. As mentioned above, the present invention is a zirconia porcelain with very little deterioration over time in a specific temperature range of 200 to 300°C, with a Y 2 O 3 /ZrO 2 molar ratio of 2/98 to 2.
In 7/93, it was discovered that it is important that the crystal phase consists mainly of tetragonal crystal grains or tetragonal crystal grains and cubic crystal grains, and that the average crystal grain size is 2 μ or less, and for this purpose, The zirconium oxide that makes up the compact has a crystallite diameter of 1000Å.
Y 2 O 3 /ZrO 2 molar ratio is 2/98 or less or amorphous
7/93 and that the firing temperature must be between 1000 and 1550℃, and the manufacturing method of the present invention has strong mechanical strength with little deterioration over time in a specific temperature range and no dimensional change due to heat treatment. Zirconia porcelain can be produced, and these porcelains can be used, for example, as heat-resistant materials, internal combustion engine components, thermistors, cutting tools, solid electrolytes, etc., and it is an extremely useful method for producing porcelain in industry.
第１図および第２図は酸化ジルコニウム粉末の
結晶子径と磁器の結晶相との関係を示す説明図で
ある。
FIGS. 1 and 2 are explanatory diagrams showing the relationship between the crystallite diameter of zirconium oxide powder and the crystal phase of porcelain.
Claims (1)
たは無定形の酸化ジルコニウムとイツトリウム化
合物より成り、Y2O3／ZrO2のモル比が２／98〜
７／93の範囲である混合物の成形体を1000〜1550
℃の温度範囲で焼成して、主として正方晶の結晶
粒子、または正方晶の結晶粒子と立方晶の結晶粒
子とよりなりかつ平均結晶粒子径が２μ以下で、
200℃ないし300℃における耐久性が優れたジルコ
ニア磁器を製造することを特徴とする磁器の製造
法。1 Consists of zirconium oxide or amorphous zirconium oxide and yttrium compound with a crystallite diameter of 1000 Å or less, and the molar ratio of Y 2 O 3 /ZrO 2 is 2/98 ~
7/93 range of 1000 to 1550
℃ fired in a temperature range of 30°C, the material is mainly composed of tetragonal crystal grains, or tetragonal crystal grains and cubic crystal grains, and has an average crystal grain size of 2μ or less,
A porcelain manufacturing method characterized by producing zirconia porcelain that has excellent durability at 200°C to 300°C.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56020833A JPS57140375A (en) | 1981-02-17 | 1981-02-17 | Ceramic manufacture |
| US06/245,280 US4360598A (en) | 1980-03-26 | 1981-03-19 | Zirconia ceramics and a method of producing the same |
| CA000373732A CA1154793A (en) | 1980-03-26 | 1981-03-24 | Zirconia ceramics and a method of producing the same |
| EP81301292A EP0036786B2 (en) | 1980-03-26 | 1981-03-25 | Zirconia ceramics and a method of producing the same |
| DE8181301292T DE3166775D1 (en) | 1980-03-26 | 1981-03-25 | Zirconia ceramics and a method of producing the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56020833A JPS57140375A (en) | 1981-02-17 | 1981-02-17 | Ceramic manufacture |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63278550A Division JPH01261267A (en) | 1988-11-05 | 1988-11-05 | Solid electrolyte and its production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57140375A JPS57140375A (en) | 1982-08-30 |
| JPS6121185B2 true JPS6121185B2 (en) | 1986-05-26 |
Family
ID=12038055
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP56020833A Granted JPS57140375A (en) | 1980-03-26 | 1981-02-17 | Ceramic manufacture |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57140375A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08503193A (en) * | 1992-11-17 | 1996-04-09 | ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング | Sintered solid electrolyte with high oxygen ion conductivity |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57140376A (en) * | 1981-02-20 | 1982-08-30 | Ngk Spark Plug Co | Partially stabilized zirconium oxide sintered body for oxygen sensor and manufacture |
| JPS60155569A (en) * | 1984-01-24 | 1985-08-15 | 東レ株式会社 | Partially stabilized zirconia sintered body |
| JPS60156473A (en) * | 1984-01-25 | 1985-08-16 | 株式会社日本メデイカル・サプライ | Medical needle |
| JPS61101462A (en) * | 1984-10-24 | 1986-05-20 | 日本碍子株式会社 | Zirconia ceramic |
| JP2617204B2 (en) * | 1988-04-27 | 1997-06-04 | 日本特殊陶業株式会社 | Method for producing solid electrolyte |
| JP2557290B2 (en) * | 1991-03-29 | 1996-11-27 | 株式会社ニッカトー | Abrasion resistant zirconia sintered body |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53128612A (en) * | 1977-04-15 | 1978-11-09 | Nippon Denso Co | Sintered zirconia for oxygen sensor |
| JPS544913A (en) * | 1977-06-14 | 1979-01-16 | Ngk Spark Plug Co | Method of making zirconia sintered body having highhstrength and oxygen ion conductivity |
| JPS5434309A (en) * | 1977-08-24 | 1979-03-13 | Yoshimitsu Hamano | Locally stabilized zirconia ceramic |
| JPS54138007A (en) * | 1978-04-18 | 1979-10-26 | Nippon Denso Co | Zirconia sintered body for oxygen concentration sensor |
| JPS55140762A (en) * | 1979-04-13 | 1980-11-04 | Kogyo Gijutsuin | Zirconia cutting tool material |
| JPS6121184A (en) * | 1984-07-10 | 1986-01-29 | Mitsubishi Electric Corp | Preparation of water-soluble anstioxidant |
-
1981
- 1981-02-17 JP JP56020833A patent/JPS57140375A/en active Granted
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53128612A (en) * | 1977-04-15 | 1978-11-09 | Nippon Denso Co | Sintered zirconia for oxygen sensor |
| JPS544913A (en) * | 1977-06-14 | 1979-01-16 | Ngk Spark Plug Co | Method of making zirconia sintered body having highhstrength and oxygen ion conductivity |
| JPS5434309A (en) * | 1977-08-24 | 1979-03-13 | Yoshimitsu Hamano | Locally stabilized zirconia ceramic |
| JPS54138007A (en) * | 1978-04-18 | 1979-10-26 | Nippon Denso Co | Zirconia sintered body for oxygen concentration sensor |
| JPS55140762A (en) * | 1979-04-13 | 1980-11-04 | Kogyo Gijutsuin | Zirconia cutting tool material |
| JPS6121184A (en) * | 1984-07-10 | 1986-01-29 | Mitsubishi Electric Corp | Preparation of water-soluble anstioxidant |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH08503193A (en) * | 1992-11-17 | 1996-04-09 | ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング | Sintered solid electrolyte with high oxygen ion conductivity |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57140375A (en) | 1982-08-30 |
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