The Research and Preparation of Low-Expansion and Transparent LAS Glass-Ceramics

The low-expansion and transparent Li_2O-Al_2O_3-SiO_2 (LAS) system glass-ceramic doped with TiO_2 and ZrO_2 as nucleation agents was prepared by traditional two-step heated schedule. The microstructure and crystalline phase were analysed by SEM and XRD, respectively. The results showe that: The β-spodumene s.s, with grain size of 50-100nm, were separated in the LAS glass-ceramic. The coefficient of linear expansion of LAS glass-ceramic was almost 0×10 -7 /K within 20-400℃ and trended to 8×10 -7 /K when the temperature increased from 400℃ to 700℃.The LAS glass-ceramic had excellent transparency and the coefficient of visible light permeation was 70%.