A new route to improve microwave dielectric properties of low-temperature sintered Li2TiO3-based ceramics
Low-temperature sintered Li2TiO3-based ceramics for low temperature co-fired ceramic resonators were synthesized by a solid state reaction method. Their microwave dielectric properties were further improved by CeO2 addition. When the amount of CeO2 increased, the relative permittivity (ε r ) of the samples increased a little and then decreased. The quality factor (Q × f) of the samples was improved obviously for a higher standard reduction potential of cerium than that of titanium. The temperature coefficient of resonant frequency (τ f ) of the samples decreased with the increase of CeO2 addition. CeO2 mainly existed as a secondary phase and it facilitated the sintering of the Li2TiO3-based ceramics. Typical microwave dielectric properties of ε r = 22.97, Q × f = 34,881 GHz, and τ f = 33.12 ppm/°C were obtained for Li2TiO3 + 2 wt% ZnO–B2O3 frit + 0.9 wt% CeO2 ceramics sintered at 920 °C for 4 h. The addition of oxidizers was proved a promising route to improve the microwave dielectric properties of titanate ceramics sintered at low temperatures.
This work was supported by the National Natural Science Foundation of China (NSFC-50902055) and China Postdoctoral Science Foundation (20110491224).