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.
KeywordsCeO2 Microwave Dielectric Property Solid State Reaction Method Linear Shrinkage Li2TiO3
This work was supported by the National Natural Science Foundation of China (NSFC-50902055) and China Postdoctoral Science Foundation (20110491224).