Nucleation of lithium aluminosilicate glass containing complex nucleation agent

The nucleation behavior of lithium aluminosilicate (Li2O–Al2O3–SiO2, LAS) glass containing complex nucleation agent (TiO2 + ZrO2 + P2O5+/or F−) were investigated by the differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM) and infrared (IR) spectroscopy. DTA of annealed glass showed that the addition of P2O5 obviously increased the transition temperature (Tg) while the addition of F− decreased it, and both P2O5 and F− decreased the temperatures (Tp) and the amount of crystallization peaks. DTA of pre-nucleated glass showed that the suitable nucleating system of the LAS glass containing P2O5 was 740 °C/1.5 h, but 700 °C/1.0 h for that containing both P2O5 and F−, both were higher than that containing no P2O5. XRD of nucleated glass showed that two nucleation phases (LiAl(SiO3)2 and LiAlSi3O8) formed and co-existed above the suitable nucleation temperature, and the formation temperature of nucleation phases for sample containing P2O5 was higher than that containing both P2O5 and F−, which coincided with the DTA results and was also confirmed by the IR and TEM analysis. The complex nucleation agent can improve the nucleation of LAS glass by F−-decreasing nucleation temperature and time and P2O5-increasing the amount of nuclei.