Crystallization Behavior and Kinetics of Lithium Aluminosilicate Glasses with Various Li₂O Contents

Abstract

The crystallization behavior of Li₂O-Al₂O₃-SiO₂ glasses with various concentration of Li₂O were investigated by DSC, XRD, and FE-SEM. The h/l-quartz s.s. is the main crystalline phase for all of the glass with the heat treatment of 720 °C/3 h+800°C/1.5 h while the crystallinity and crystal size increase with the increase of Li₂O contents. Due to the negative thermal expansion coefficient of h/l-quartz s.s., the thermal expansion coefficient of glass-ceramics decreases with the increasing of Li₂O contents. When the Li₂O content is 9mol%, the near-zero CTE_{20–700 °C}= −0.09 × 10⁻⁶ °C⁻¹ is obtained upon the heat treatment of 720 °C/3 h+800 °C/1.5 h. The crystallization activation energy of the glass with 9mol% Li₂O is about 351 kJ/mol, and the crystallization mechanism is volume crystallization.

Keywords

LAS glass-ceramics / crystallization / zero thermal expansion / kinetics