YU Junling ¹, BAO Zhenhong ^{1, 2}, MIAO Lifeng ², WANG Tao ¹, JIANG Feng ¹, LIU Jianmin ²
(1. School of Material Science and Engineering, Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China. 2. National Engineering Research Center for Domestic & Building Ceramics, Jingdezhen 333000, Jiangxi, China)

Abstract: AR₂O-MgO-Al₂O₃-SiO₂(RMAS, R=Li, Na, K) glaze with low thermal expansion and low content of Li₂O was developed. The effects of Li₂O on structure and properties of the RMAS glaze were studied. The action mechanism of Li₂O was examined by using high temperature microscope, XRD, DTA, FE-SEM and AFM. With increasing content of Li₂O, fluidity of the RMAS glaze decreases first and then increases, while the crystal phase transforms from α-cordierite to α-cordierite and β-eucryptite solid solution (LixAlxSi₃−xO₆). The coefficient of thermal expansion decreases from 3.79×10⁻⁶ ℃⁻¹ (α _{L 20-600 ℃}) to 1.22×10⁻⁶ ℃⁻¹ (α _{L 20-600 ℃}), as the content of Li₂O is increased from 0 wt.% to 2.35 wt.%. When the content of Li₂O is 1.96 wt.%, the RMAS glaze possesses the highest comprehensive properties, with the highest α-cordierite content of 25.5 wt.% and coefficient of thermal expansion of 1.42×10⁻⁶ ℃⁻¹ (α _{L 20-600 ℃}). Compared with that of the sample without Li₂O, the activation energy values for the formation of α-cordierite in the RMAS glaze with 1.96 wt.% Li₂O decreased from 750.6 kJ·mol⁻¹ to 687.5 kJ·mol⁻¹.
Key words: glaze; low Li₂O content; α-cordierite; β-eucryptite