Low-temperature sintering and microwave dielectric properties of (Zr,Sn)TiO4 ceramics

Zirconium tin titanate ceramics, especially the Zr0.8Sn0.2TiO4 (ZST) ceramics, suitable for use in resonators or filters at microwave frequency, have a high Q value and a low temperature coefficient of resonant frequency. However, the sintering temperature still remained as high as 1350 °C. The methods including glass additions, wet chemical processing, and liquid-phase sintering aids have been used to lower the sintering temperature of ZST ceramics. Using glass additives was found to effectively lower the sintering temperature. Nevertheless, it decreased the microwave dielectric properties of ZST ceramics. The wet chemical processes, especially the coprecipitation route, offered advantages over traditional processing techniques, but often required a complicated procedure that would increase the cost and time in fabricating the ZST ceramics. In contrast, the sintering temperature of ZST ceramics with BaCuO2+CuO,CuO, or V2O5 additions could be effectively reduced without decreasing the microwave dielectric properties due to the liquid phase effects. The microwave dielectric properties of ZST ceramics were sensitive to processing conditions and microstructure features. The dielectric constants were not significantly affected by various additives while the quality factors were strongly dependent on the type and the amount of additives.