Glass Separation and Crystallization Behaviors of the Pseudo-binary 3SiO2·B2O3—Li2O System

• Main Authors: Yuen-Tsong Chang, 張淵琮
• Other Authors: Wei-Teh Jiang
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/64008334080337168037

碩士 === 國立成功大學 === 地球科學系 === 88 === Abstract Boron anomaly and liquid immiscibility are usually happened in boron silicate glass and make chemical properties of boron silicate glass unstable and inhomogeneous. The conditions of boron anomaly and liquid immiscibility are mainly affected by the species and concentration of the alkali elements added and the procedure that glass manufactured. But the phase behaviors of the SiO2—B2O3—Li2O trinary system are mysteries till now. We propose to study on 3SiO2‧B2O3—Li2O binary system in concentration of Li2O between 0 mol% to 30 mol% with operation thermal between 750℃ to 1050℃. It is a pseudo-binary system that estimated in this project with six phases including quartz, sassolite, cristobalite, Li2Si2O5, Li2SiO3 and X phase. The various glass quantities were observed under microscopes. In some parts of glass samples immiscibility that found containing two existing types, droplet-shaped and spindle-shaped, distributing in certain components and operation temperature, still, in one particular condition, both can be found. There are two degrees of orders observed by X-ray diffraction, and they are extended medium-range order and medium-range order. The Raman spectrostropic shows that the glass is of boron silicate. Crystallization behaviors of this study are affected by operation temperature and the concentration of the Li2O. Distributions of spindle-shaped immiscibility are affected by the concentration of the Li2O, and of droplet-shaped one are affected by the operation temperature and the concentration of the Li2O. There exist differences in behaviors of crystallization and the co-existing thermal range of two-liquids to previous study. Perhaps, the resulting meta-stable system will always carry out the unstable phases and immiscibility.