Nucleation and crystallization behavior of Li2O–Al2O3–SiO2 system glass–ceramic containing little fluorine and no-fluorine

The nucleation and crystallization behavior of Li2O–Al2O3–SiO2 system (LAS) glass–ceramics containing little fluorine and no-fluorine are investigated by the differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). TEM of the annealed glass shows that the nucleation has appeared during the annealing stage. DTA of pre-nucleated glass shows that the optimum nucleating temperature of the LAS glass containing fluorine is 620 °C and 40 °C lower than that containing no-fluorine. XRD and SEM show that the optimum crystallizing temperature of the LAS glass containing fluorine is 760 °C, 110 °C lower than that containing no-fluorine, and the optimum crystallizing time is 4 h. The introduction of fluorine can decrease the crystallizing peak temperature (Tp) and the crystallizing activation energy (E) and improve the crystallization stage to obtain fine crystal with a size of 150 nm.