THE EFFECT OF COMPLEX NUCLEATING AGENT ON THE PHYSICAL AND CHEMICAL PROPERTIES OF Li۲O-Al۲O۳-SiO۲ GLASS CERAMIC

Abstract: In the present work, effect of the nucleating agent such as TiO۲, ZrO۲, P۲O۵, Ye۲O۳ and CeO۲ in single, double, triple and fourth systems on the crystallization behavior of various compositions was studied. Using differential thermal analysis (DTA), the composition of Li۲O-Al۲O۳-SiO۲ (LAS) was optimized and the coefficient of thermal expansion (CTE), three point flexural strength, hardness, thermal shock resistance, and chemical resistance of the most favorable composition were evaluated. The crystalline phase was determined by the x-ray diffractometry. Moreover, the micro-structure of the samples was studied by SEM technique. According to the results, -Eucryptites (high quartz solid solution) was the main crystalline phase and the CTE values of the optimized sample were determined as ۱.۶۵-۱.۹۳ ۱۰-۶ in the temperature range of ۲۰-۵۰۰ oC. Furthermore, three point bending strength ranged from ۱۳۹ to ۱۵۵ MPa.

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Keyword: Glass ، LAS Glass Ceramic ، Eucryptite ، Low Thermal Expansion .