Effect of heat-treatment on the dielectric properties of CaMgSi2O6 glass-ceramics with Cr2O3–Fe2O3–TiO2

Abstract

The dielectric properties of CaMgSi2O6 glass-ceramics were investigated at microwave frequencies as a function of Cr2O3–Fe2O3–TiO2 (CFT) content and heat-treatment method. The specimens with 0.5 wt % CFT heat-treated at 900 °C for 3 h showed the maximum degree of crystallization and a high quality factor (Qf, 53,000 GHz). The temperature coefficient of the resonant frequency (TCF) did not remarkably change with CFT content. To obtain the optimum Qf value, the specimens with 0.5 wt % CFT were heat-treated by the two-stage method. While the specimens heat-treated at 757 °C for 3 h and/or 5 h and crystallized at 900 °C for 3 h showed the lower Qf than that of the specimens heat-treated at 900 °C for 3 h by the single-stage method, due to the re-dissolution of the nuclei formed at Tn, whereas the specimens heat-treated at 757 °C for 10 h and crystallized at 900 °C for 3 h showed the improved Qf value. The maximum Qf (62,000 GHz) was observed for the specimens heat-treated at 757 °C for 10 h and crystallized at 950 °C for 3 h.