| ZrO2 입자의 분산방법에 따른 Al2O3/ZrO2 요업체의 특성 |
| 연상흠, 김재준, 황규홍, 이종국1, 김환2 |
경상대학교 신소재공학부
1조선대학교 신소재공학과
2서울대학교 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 University
1Department of Advanced Materials, Engineering, Chosun University
2Division 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 |
|
|
|
PDF Links
Full text via DOI
Download Citation 
