Crystallization behavior and microwave dielectric property of MgO–Al2O3–SiO2–TiO2–CeO2 glass–ceramic

Glass–ceramics with a molar composition of 1.0MgO·1.2Al2O3·2.8SiO2·1.2TiO2·0.6CeO2, was prepared by one-step crystallization heat treatment of the parent glass at different temperatures for 2 h. The crystallization behavior and microwave dielectric properties of the materials were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and network analyzer. The investigations show that the exothermic peaks in the range of 841–1220 °C are corresponding with perrierite (Ce2Ti2Si2O11), magnesium aluminotitanate (Mg2Al6Ti7O25, MAT), rutile (TiO2), α-cordierite (Mg2Al4Si5O18) and ceria (CeO2), respectively. The microwave dielectric properties are correlated with the treatment conditions. With the heat-treatment temperature is increased in the range of 1100–1250 °C, the dielectric constant (ɛr) of the material varies in the range of 10.99–11.73. It increases first and then decreases, with the maximum value of 11.73 appearing at 1200 °C. At the same time, the quality factor (Q × f, Q = 1/tan δ, f = resonant frequency) of the material shows the similar variation, with a maximum value of 17,3000 GHz appearing at 1200 °C. However, the temperature coefficient of resonance frequency (τf) of the material increases from 26.3 to 75.9 ppm/°C because of the increase in the perrierite phase. A new glass–ceramic with excellent microwave dielectric properties of ɛr = 11.73, Q × f = 17,300 GHz, τf = 48.5 ppm/°C, was obtained in this study.