Effects of CaTiO_3 addition on the microstructure and microwave dielectric properties of α-CaSiO_3-SiO_2 ceramics

摘要

The effects of CaTiO_3 addition on microstructure and microwave dielectric properties of α-CaSiO_3-6 wt% SiO_2 have been investigated. The X-Ray Diffraction (XRD) patterns results indicate that samples exhibit a three-phase system, which has a wollastonite-structured α-CaSiO_3 primary phase associated with SiO_2 and CaTiO_3 minor phase. It was observed that the average grain size increased with the increasing addition of CaTiO_3 by Scanning Electron Microscope (SEM). The τ_f value is strongly correlated to the compositions and can be controlled through the compositional ratio. The α-CaSiO_3-6 wt% SiO_2 ceramics containing 2.5 wt% of CaTiO_3 sintered at 1350°C showed excellent microwave dielectric properties: an ε_r value of 7.86, a quality factor Q × f value of 21,035 GHz, and a τ_f value of 0.59 ppm/°C.