Preparation and Characteristics of <tex>$Y_2O_3-CeO_2-ZrO_2$</tex>Structural Ceramics ; I. Synthesis and Sinterability of Powder

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J. Korean Ceram. Soc. > Volume 33(9); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(9): 1057.

$Y_2O_3-CeO_2-ZrO_2$ 구조세라믹스의 제조 및 특성 : I 분말의 합성 및 소결성

오혁상, 이윤복, 김영우¹, 오기동, 박흥채

부산대학교 무기재료공학과
¹포항산업과학연구원

Preparation and Characteristics of $Y_2O_3-CeO_2-ZrO_2$Structural Ceramics ; I. Synthesis and Sinterability of Powder

ABSTRACT

Y2O3-CeO2-ZrO2 powders were prepared from water-soluble salts using a coprecipitation method. The forming process of oxide and the characteristics of the calcined powders treated in different drying conditions were investigated. The oxidation was occurred at the temperature of around 40$0^{circ}C$ and the main crystallization of ZrO2 around $600^{circ}C$. On calcination at $600^{circ}C$ heating lamp-dried powders consisted of agglomerates of globular morphology with average agglomerate size of 2.27${mu}{textrm}{m}$ and specific surface area of 68.3m2/g and spray dried powders contained dense spheric particles with average agglomerate size of 1.35${mu}{textrm}{m}$ and specific surface area of 11.0m2/g which exhibited low agglomeration tendency. Removal of the water by a freeze-drying technique produced calcined powders containing flake-like secondary particle structures with wide agglomerate size distri-bution of 0.1-60${mu}{textrm}{m}$ and specific surface area of 24.5${mu}{textrm}{m}$. The 20 MPa-pressed density (36.8-41.4% T,D) of calcined powders did not nealy depend on drying methods whilst compaction ratio of calcined powders derived from freeze-drying was the highest ( 6.24) among three drying methods. On continuous heating up to 150$0^{circ}C$ the sinterability of calcined powders derived from heating lamp-drying was superior to those derived from spray-and freeze-drying. The final sintered density of calcined powders was the highest (96% T,D at 150$0^{circ}C$) in case of heating lamp-drying.

Key words: $Y_2O_3-CeO_2-ZrO_2$ powders, Oxidation, Crystallization, Calcination, Sinterabilyt, Heating lamp-drying, Spray-drying