J. Korean Ceram. Soc. > Volume 42(8); 2005 > Article
 Journal of the Korean Ceramic Society 2005;42(8): 561. doi: https://doi.org/10.4191/kcers.2005.42.8.561
 ZrO2 입자의 분산방법에 따른 Al2O3/ZrO2 요업체의 특성 연상흠, 김재준, 황규홍, 이종국1, 김환2 경상대학교 신소재공학부1조선대학교 신소재공학과2서울대학교 재료공학부 Characteristics of Al2O3/ZrO2 Ceramics by the Dispersion Process of ZrO2 Particles Sang-Hum Youn, Jae-Jun Kim, Kyu-Hong Hwang, Jong-Kook Lee1, Hwan Kim2 Division of Advanced Materials Engineering, Engineering Research Institute, Gyeongsang National University1Department of Advanced Materials, Engineering, Chosun University2Division of Materials Engineering, Seoul National University ABSTRACT For the homogeneous dispersion of $ZrO_2$ particles in $Al_2O_3/ZrO_2$ceramics, Zr-precusors were mixed with oxide $Al_2O_3$powders by chemical routes such as partial precipitation or partial polymerization of Zr-nitrate solutions. In case of the mechanical mixing of ultrafine $Al_2O_3$ and $ZrO_2$ oxide powders, relatively homogeneous dispersion was difficult to achieve so that the particle size and distributions of $ZrO_2$ were relatively inhomogeneous after sintering at high temperature. But when the Zr-Y-hydroxide were co-precipitated to ultrafine $Al_2O_3$ oxide powders followed by calcinations, homogeneous dispersion of nano-sized $ZrO_2$ particles in $Al_2O_3/ZrO_2$ composite ceramics were obtained. But because of the coalescence of dispersed $ZrO_2$ particles, dispersed $ZrO_2$ was grown up to more than 0.2${mu}m$ (200 nm) when sintered at the temperature of higher than $1500^{circ}C$ But when the sintering temperature was kept to lower than $1400^{circ}C$ by using nano-sized $alpha-alumina$, the particle size of dispersed $ZrO_2$ could be sustained below 0.1 ${mu}m$. But the coalescence of dispersed $ZrO_2$ between $Al_2O_3$ particles could not be avoided so that the mechanical properties were not enhanced contrary to the expectations. So Zr-polyester precursors were precipitated and coated to the surface of ultrafine $alpha-alumina$ powders by the polymerization of Ethylene Glycol with Citric Acid and Zirconium Nitrate. By this dispersion much more uniform dispersion of $ZrO_2$ was achieved at $1450~1600^{circ}C$ of sintering temperature ranges. And due to especially discrete dispersion of $ZrO_2$ between $Al_2O_3$ particles, their mechanical strength was more enhanced than mechanical mixing or hydroxide precipitation methods. Key words: Partial co precipitation, Polymeric precursor method
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