Phase Stability and Physical Properties of <TEX>$ZrO_2$</TEX> doped with <TEX>$Y_2O_3$</TEX> and <TEX>$Nb_2O_5$</TEX>

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J. Korean Ceram. Soc. > Volume 34(6); 1997 > Article

Journal of the Korean Ceramic Society 1997;34(6): 645.

$Y_2O_3$와 $Nb_2O_5$가 첨가된 $ZrO_2$의 상 안정성 및 물리적 성질

이득용, 김대준¹, 조경식¹, 장주웅²

대림전문대학 금속재료과
¹KIST 세라믹스부
²연세대학교 세라믹공학과

Phase Stability and Physical Properties of $ZrO_2$ doped with $Y_2O_3$ and $Nb_2O_5$

ABSTRACT

Tetragonal zirconia polycrystals (TZPs) doped with $Y_{2}O_{3}$ and $Nb_{2}O_{5}$ were prepared by the conventional sintering to enhance fracture toughness and phase stability of TZPs without controlling the grain size. TZP composites were obtained by adding the transformable TZP to the non-transformable TZP in wt%. The monolithic tetragonal $ZrO_2$, same as the composite composition containing 15 wt% transformable TZP, sintered at $1550^{circ}C$ for 10h in air, exhibited the fracture toughness of 9$MPam^{1/2}$ and no low-and high-temperature degradation at temperatures in the range of 220 to $1000^{circ}C$ for 100h in air. The corresponding single composition was 90.24 mol% $ZrO_2$-5.31 mol% $Y_{2}O_{3}$-4.75 mol% $Nb_{2}O_{5}$. The microstructure observation revealed that the t-$ZrO_2$ grains grew grandually with sintering time and no microcraking and twinning were observed.

Key words: Tetragonal $ZrO_2$ polycrystal (TZP), Non-transformable TZP, Transformable TZP, Composite, Monolith, Low-Temperature Phase Stability