Densification and Crystallization Characteristics of LAS Gels Prepared by the Hydrolysis-Condensation Reaction and the Mixed Colloidal Processing Route

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J. Korean Ceram. Soc. > Volume 28(11); 1991 > Article

Journal of the Korean Ceramic Society 1991;28(11): 865.

가수분해-축합반응 및 콜로이드 혼합법으로 유도된 LAS gel의 치밀화와 결정화 특성

김광수, 장현명¹, 정창주

전남대학교 공과대학 무기재료공학과
¹포항공과대학 재료공학과 정밀세라믹스 공정과학 연구실

Densification and Crystallization Characteristics of LAS Gels Prepared by the Hydrolysis-Condensation Reaction and the Mixed Colloidal Processing Route

ABSTRACT

LAS (lithium aluminosilicate) sol was synthesized using the hydrolysis-condensation reaction of TEOS, chelated Al(OBus)3 and LiNO3 with H2O in alcohol (ethanol+2-propanol) medium. Lowering Li content by a factor of 1/2 significantly enhanced densification and retarded the crystallization of LAS gel by ~30$0^{circ}C$. Dense LAS specimen with essentially pore-free microstructure was obtained by sintering the sol-gel derived gel at 80$0^{circ}C$ for 4 h and annealing at 120$0^{circ}C$ for 2 h. Similary, a mixed colloidal processing was attempted as a convenient, alternative route for the fabrication of dense LAS sintered body. The $beta$-spodumene seeding (~0.8 ${mu}{textrm}{m}$) in the sol-gel derived LAS modified the sequence of phase transformations and lowered the temperature of crystallization by ~12$0^{circ}C$. Combining the epitaxial seeding with the sol-gel process, we could lower the crystallization temperature to the sintering temperature range (~80$0^{circ}C$) and, demonstrate a possibility of making the viscous sintering/crystallization as a continuous as a continuous unit process.