Effects of GeO2 Addition On the Crystallization , Thermal Expansion, and Optical Transparency of Li2O-Al2O3-SiO2 Glass-Ceramics

• Main Authors: Chun-Yuan Lue, 盧俊元
• Other Authors: Jiin-Jyh Shyu
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/91793444628828685209

碩士 === 大同大學 === 材料工程學系(所) === 93 === Li2O-Al2O3-SiO2 glass-ceramics containing nano-sized h-quartz s.s. crystals have optical transparency and ultra-low thermal-expansion coefficient. The objective of the thesis is to explore the effect of GeO2 addition on the crystallization and properties of Li2O-Al2O3-SiO2 glass-ceramics. It is expected that the viscosity of the parent glass will be reduced to profit glass shaping, and the IR transmission cut-off will be shifted to longer wavelength. The experimental results indicated that viscosity of glass reduced with the increase in GeO2 content. A single h-quartz s.s. phase can be formed in the parent glass subjected to nucleation and crystallization thermal treatment. The crystal size increased with the increasing GeO2 content, affecting the optical transmission in visible region for the glass ceramics. Although the conditions of thermal treatment to gain good transmission (70%) is more narrow with the increase in GeO2 content, materials with the transmission closed to Zerodur® can still be obtained. The coefficient of thermal expansion of glasses and glass-ceramics that contain GeO2 was increased with respect to the GeO2 free composition. Addition of GeO2 is useless on extending the IR transmission cut-off wavelength for glasses and glass-ceramics.