J. Korean Ceram. Soc. > Volume 29(12); 1992 > Article
 Journal of the Korean Ceramic Society 1992;29(12): 935.
 $Li_2O-Al_2O_3-SiO_2$계 소지내에 Zircon상 형성에 따른 내열 강화 특성 전덕일, 김정욱, 이응상 한양대학교 무기재료공학과 A Study on the Thermal Resistance Strength with the Formation of the Zircon Phase in LAS System ABSTRACT The LAS system with good thermal properties has a narrow range of firing and sintering temperature near the melting point. So it is difficult to sinter LAS to dense sintered body. In this study, the petalite (Li2O.Al2O3.8SiO2) with good thermal properties, was taken as a base composition, and zironia was added in this composition to broaden the firing range, increase the mechanical strength, and control the thermal expansion. The thermal and mechanical properties were investigated. The results are as follows; 1. Zirconia phase was formed in LAS matrix and apparent porosity was decreased from 0.9% to 0.5%, and the mechanical strength was kincreased from 112 MPa to 190 MPa, by the densification of body. 2. The composition Li2O.Al2O3.8SiO2 has a negative thermal expansion, but the thermal expansion was changed from negative to positive with the densification and the increase of amount of synthesized zircon phase which had positive thermal expansion. The coefficient of thermal expansion, with the increase of the amount of additives, was low as -0.74~9.06$times$10-7/$^{circ}C$ in 20~$600^{circ}C$, and 7.95~20.13$times$10-7/$^{circ}C$ in 20~80$0^{circ}C$. 3. The mechanical strength of LZ15 (added with ZrO2.SiO2 15 wt%) composition thermal-shocked was stable in the temperature range of 0~$600^{circ}C$, but rapidly decreased due to the increase of thermal expansion above $600^{circ}C$.
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