Studies on the Crystal Growth in  ZnO-AI<TEX>$_2$</TEX>O<TEX>$_3$</TEX>-SiO<TEX>$_2$</TEX>Glass

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J. Korean Ceram. Soc. > Volume 12(1); 1975 > Article

Journal of the Korean Ceramic Society 1975;12(1): 23.

ZnO-Al$_2$O$_3$-SiO$_2$ 유리에서의 결정성장에 관한 연구

이종근, 이병하¹

한양대학교요업공학과
¹한양대학교 요업공학과

Studies on the Crystal Growth in ZnO-AI$_2$O$_3$-SiO$_2$Glass

ABSTRACT

The object of this study is to find the optimum conditions for crystal growth and kinds of crystal in ZnO-Al2O3-SiO2 glass composition. At first, the base glass composed of ZnO (44.7%), Al2O3(14.0%) and SiO2(41.3%) was melted in propane gas furnace at 1450-150$0^{circ}C$ for an hour, and then it was poured into the stainless steel mould heated previously at $600^{circ}C$ to obtain the thin glass test piece. Four crystal forms from base glass such as stuffed keatite, zinc orthosilicate, zinc aluminosilicate, and cristobalite were crystallized during heat treatment between 80$0^{circ}C$ and 110$0^{circ}C$. For the investigation of crystal growth, X-ray diffractometer and thermal differential analysis were used and the growth rate of the four crystal forms were obtained by the method of Archimedes specific gravity and intensity comparison of X-ray diffraction peak. The results obtained were as follows. 1) Stuffed keatite peaks which started to appear after two hours at 80$0^{circ}C$ were maximum after 11 hours and this crystal breaks down to willemite irreversibly at about 100$0^{circ}C$. 2) Development of gahnite started at 85$0^{circ}C$ and increased with temperature growth. 3) Stuffed keatite which had been transformed slowly into willemite at 100$0^{circ}C$ was decreased with time and willemite increased until four hours. 4) Cristobalite began to be developed after treatment of 110$0^{circ}C$.