| Sol-Gel 법에 의한 $Li_2O-Al_2O_3-TiO_2-SiO_2$ 계 다공성 결정화 유리의 제조 : (II) Sol-Gel 법에 의해 제조된 $Li_2O-Al_2O_3-TiO_2-SiO_2$ 계 괴상겔의 결정화 |
| 조훈성, 양중식1 |
마산전문대 환경관리과
1경희대학교 화학과 |
| Preparation of Glass-Ceramics in $Li_2O-Al_2O_3-TiO_2-SiO_2$ System by Sol-Gel Technique : (II) Crystallization of $Li_2O-Al_2O_3-TiO_2-SiO_2$ Monolithic Gel Prepared by Sol-Gel Method |
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| ABSTRACT |
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The monolithic dry gels of the Li2O-Al2O3-TiO2-SiO2 system were prepared by the sol-gel technique using metal alkoxides as starting materials to obtain monolithic glass-ceramics at low temperature without melting. Activation energy for the crystal growth of the gel with 6.05% TiO2, nucleating ageng, for the preparation of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was 101.14kcal/mol. As a result of the analysis of DTA & XRD, it was confirmed that the crytallization of Li2O-Al2O3-TiO2-SiO2 system glass-ceramic was the most efficient when 6.05% TiO2, nucleating agent, was added. $beta$-eucryptite solid solution crystals and $beta$-spodumene solid solution crystals were detected in the sample heat treated above 85$0^{circ}C$. The sintered gel heat treated at 85$0^{circ}C$ had the specific surface area of 185$m^2$/g, the pore volume of 0.19cc/g and the average pore radius of 20.8$AA$. This shows that the sintered gel is also comparatively porous material. In temperature range of 25~85$0^{circ}C$ thermal expansion coefficient of the specimen which was crystallized for 10hrs at 85$0^{circ}C$ was 6.7$times$10-7/$^{circ}C$, which indicated that the crystallized specimen was turned out to be the glass-ceramic with low thermal expansion. |
| Key words:
Sol-gel method, Lithium alminosilicate glass-ceramics, Crystallization, Porous material, Low thermal expansion |
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