Low-temperature sintering and microwave dielectric properties of (Zn1−xCox)2SiO4 ceramics

(Zn1−xCox)2SiO4 (0≤x≤0.1) powders were synthesized by the traditional solid-state process. Fixed amount of Li2O-B2O3-SiO2-CaO-Al2O3 (LBSCA)glass was added to (Zn1−xCox)2SiO4 powders to decrease the sintering temperature around 900 °C. The X-ray diffraction (XRD) diffraction spectra indicated that there was no second phase formed while the Scanning Electron Microscope (SEM) images demonstrated that moderate Co-substitution contributed to the grain densification and uniformity in (Zn1−xCox)2SiO4 system. Moreover, the microwave dielectric properties strongly depended on the substitution content and sintering temperature. When sintered at 900 °C, the sample with 0.05 Co substitution presented a compact microstructure with uniform grains and high microwave dielectric properties: εr=6.5, Q×f=57,000 GHz and τf=−55 ppm/°C.