Preparation of Glass-Ceramics in $Li_2O-Al_2O_3-TiO_2-SiO_2$ System by Sol-Gel Technique : (I) Preparation of Porous Monolithic Gel in $Li_2O-Al_2O_3-TiO_2-SiO_2$ System by Sol-Gel Method

Sol-Gel법에 의한 $Li_2O-Al_2O_3-TiO_2-SiO_2$계 다공성 결정화 유리의 제조 : (I) Sol-Gel 방법에 의한 $Li_2O-Al_2O_3-TiO_2-SiO_2$계 다공성 겔체의 제조

  • Published : 1993.07.01

Abstract

It was investigated in this study that a preparation method, activation energy, surface area, pore volume, pore size distribution and DTA analysis of the dry gel in process of producing monolithic porous gel in Li2O-Al2O3-TiO2-SiO2 system by the sol-gel technique using metal alkoxides. Activation energy for gellation according to the variation of water concentration and the kind of catalysts ranged from 10 to 20kcal/mole. Monolithic dry gels were prepared after drying at 9$0^{\circ}C$ when the amount of water for gellation was 4~8 times more than the stoichiometric amount, that was necessary for the full hydrolysis of the mixed metal alkoxide. The specific surface area, the pore volume, the average pore radius of the dried gel at 18$0^{\circ}C$ according to the various kinds of catalyst were about 348~734$m^2$/g, 0.35~0.70ml/g and 10~35$\AA$, respectively. It showed that the dry gels were porous body. As a result ofthe analysis of DTA, it was confirmed that the exothermaic peaks at 715$^{\circ}C$ and 77$0^{\circ}C$ was clue to the crystallization of dried gel.

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