J. Korean Ceram. Soc. > Volume 29(7); 1992 > Article
 Journal of the Korean Ceramic Society 1992;29(7): 558.
 $CaO-MgO-Al_2O_3-SiO_2$계의 글라스-세라믹에서 결정상이 소결체에 미치는 영향 김형순 순천대학교 금속공학과 무기재료분야 Effect of Crystal Phases on the Properties of Sintered Glass-Ceramics for $CaO-MgO-Al_2O_3-SiO_2$ System ABSTRACT The effect of composed phase in the hot pressed CaO-MgO-Al2O3-SiO2 glass-ceramic has been investigated through microstructure studies, thermal, physical and mechanical properties. Sintering was done in the condition at the temperature range 900~95$0^{circ}C$ for 20~120 mins under 7.5 MPa unilateral pressure. Sintered ceramics were composed of diopside, anorthite, residual glass and the portion of each phase was dependent on the sintering temperature and the holding time: as the temperature increases, the amount of diopside increased and then the rate of increase of diopside reduced with increasing anorthite. The thermal expansion coefficient of hot pressed was reduced with increasing crystallinity of hot pressed and was in the range of 6.69~7.46$times$10-6 K-1 below $600^{circ}C$. The elastic constant of hot pressed increased with increasing crystallinity up to about 80%, but after that was reduced due to the change of microstructure. The flexural strength of sintered ceramics was decreased with higher temperature and holding time, while the fracture toughness of those increased. It was shown that the physical and mechanical properties of hot pressed ceramic were related to the fraction of composed sintered ceramics, similar to a particulate composite, to the crystallinity of 80% of the glass-ceramic.
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