Effects of crystallisation process on thermal expansion property of lepidolite glass ceramics of Mg0-Al203-Si02-Li20-R20-F (R=Na, K) system were studied. The results show that the thermal expansion coefficient of lepidolite glass-ceramics decreases with the increase of crystallization temperature above 1050 deg C. Prolonging heat treatment time has the same effect as crystallization temperature. The reasons are attributable to the increase in beta-spodumene, which has low thermal expansion coefficient, and micropores and microcracks in the glass-ceramics, which lead to low macroscopic thermal expansion. Besides, the results are also revealed that the properties of thermal expansion coefficient, bending strength and machineability can be optimised according to application demand.
