Preparation and thermal properties of P2O5 doped Li2O-Al2O3-SiO2 glass-ceramics

Using TiO(2) and ZrO(2) as compound nucleation agent, serials Li(20)-Al(2)O(3)-SiO(2) (LAS) glasses containing different content of P(2)O(5) were prepared by conventional melt quenching technique and subsequent converting to glass ceramics. The influence of P(2)O(5) content on viscosity of LAS glasses was investigated in the temperature range from the softening point to melting temperature. DSC was undertaken to analyze the change of characteristic temperature Tg, Tc and Tp. Thermal expansion coefficient (TEC) of matrix glass and glass-ceramic containing different P(2)O(5) were measured. The results show introducing P(2)O(5) effectively decreased the melting temperature and viscosity of LAS glasses. TECs of the matrix glass and glass-ceramic range from 4.1 x 10(-6) C(-1) to 5.3 x 10(-6) degrees C(-1) and from -0.2 x 10(-6) degrees C(-1) to 1.2 x 10(-6) degrees C(-1), respectively. XRD analysis indicates that beta-spodumene is the main crystalline phase in the P(2)O(5) doped LAS glass-ceramics, resulting in the low thermal expansion coefficient of the glass-ceramics.