Abstract: The crystallization process and microwave dielectric properties of MgO-Al₂O₃-SiO₂-TiO₂-CeO₂ system glass-ceramics were studied by means of DTA, XRD, SEM and TEM. The results show that the parent glass has already been two-phase separated before nucleation
and crystallization. The droplet phase is rich in Ti⁴⁺ and Ce⁴⁺, and the matrix phase is rich in Si⁴⁺ and Al³⁺. During heat-treatment of
the glass, rutile nucleates in the droplet phase at about 800℃ and perrierite appears at 900℃. At 1100℃, α-cordierite precipitates from the matrix phase. With increasing the heat-treatment temperatures,
the crystallized volume fraction of the glass increases, which leads to the increase of the microwave dielectric constant (ε_r) and the decrease of
the microwave loss (tgδ). However, at temperatures higher than 1100℃, ε_r decreases because of the precipitation of large amount of
α-cordierite. At the same time, tgδ increases slightly because of the coarse structure of the crystals. The glass-ceramics obtained by crystallization
of the glass have dielectric constant of 8～11, and microwave loss less than 6×10^-4.

Key words: glass-ceramics, crystallization, microwave dielectric property