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.