Influence of ZnO additions to 0.96Mg_0.95Co_0.05TiO₃-0.04SrTiO₃ ceramics on sintering behavior and microwave dielectric properties

The effects of ZnO addition on the microstructures and microwave dielectric properties of 0.96Mg_0.95Co_0.05TiO₃-0.04SrTiO₃ ceramics were investigated. ZnO was selected as liquid phase sintering aids to lower the sintering temperature of 0.96Mg_0.95Co_0.05TiO₃-0.04SrTiO₃ ceramics. With ZnO additives, the densification temperature of 0.96Mg_0.95Co_0.05TiO₃-0.04SrTiO₃ can be effectively reduced from 1450 °C to 1250-1350 °C. The crystalline phase exhibited no phase difference at low addition levels (0.5-4 wt%). It is found that low-level doping of ZnO (0.5-4 wt%) can significantly improve the density and dielectric properties of 0.96Mg_0.95Co_0.05TiO₃-0.04SrTiO₃ ceramics. The quality factors Q × f was strongly dependent upon the amount of additives. Q × f values of 74,000 GHz and 30,000 GHz could be obtained at 1250-1350 °C with 1 wt% and 4 wt% ZnO additives, respectively. During all additives ranges, the relative dielectric constants were not significantly different and ranged from 20.1 to 27.77. The temperature coefficient varies from -8 ppm/°C to 2.7 ppm/°C.