Synthesis and Application of Nanoparticulate Aluminosilicate Sols (II) Mixed <TEX>Al_2O_3-SiO_2$</TEX> Sols

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J. Korean Ceram. Soc. > Volume 32(1); 1995 > Article

Journal of the Korean Ceramic Society 1995;32(1): 63.

극미세 입자 Aluminosilicate계 졸의 합성 및 응용 (II) Al_2O_3-SiO_2$계 혼합졸

현상훈, 김승구, 이성철

연세대학교 세라믹공학과

Synthesis and Application of Nanoparticulate Aluminosilicate Sols (II) Mixed Al_2O_3-SiO_2$ Sols

ABSTRACT

A crack-free ceramic composite membrane with micropores has been synthesized by the pressurized sol-gel coating technique using the mixed Al2O3-SiO2 sols. The mixed sols were prepared by mixing nanoparticulate SiO2 and boehmite sols. These sols were more stable at lower pH, but very unstable when their copositions were in the range of 50~75mol% of SiO2 at the same pH. The mixed Al2O3-SiO2 membrane prepared from the mixed sol (0.2mol/$ell$ of solid content and pH=2) containing 40mol% of SiO2 had the mean pore radius of 0.80nm and the specific surface area of 280$m^2$/g. The nitrogen permeability through the coated Al2O3-SiO2 layer was 42$times$107mol/$m^2$.s.Pa. It was found that the thermal stability of aluminosilicate membranes, even through similar to that of SiO2 membranes, was much improved in comparison with ${gamma}$-alumina membranes.

Key words: Mixed Al2O3-SiO2 sol, Pressurized Sol-gel coating technique, Ceramic composite membrane, N2 gas permeability, Thermal stability