Phase Transition and Dielectric Properties of MgO-Al_2O_3-SiO_2-TiO_2 Glass-ceramics Adding CeO_2

The glass-forming, the crystallization process and microwave dielectric properties of MgO-Al2O3-SiO2-TiO2 system glasses adding CeO2 were investigated by means of DTA, XRD, SEM. Results show that spontaneous crystallization of the MgO-Al2O3-SiO2-TiO2 system glasses is obviously prevented with the increass of CeO2 content. After heat treatment (nucleation at 770℃for 4h and cryatal growth at 1200℃for 1.5h) the crystallized volume fraction of rutile and cordierite decrease and that of perrierite increases. The glass-ceramics obtained by crystallization of the glasses have dielectric constant of 7.5-10.5, and microwave loss less than 5.5×10-4.