Microwave Dielectric Properties of Li 3 TiO 3 F Oxyfluorides Ceramics.

Using a solid-state reaction strategy, nominal Li₃TiO₃F oxyfluorides ceramics were fabricated, and its sintering behavior, microstructure, phase assemblages, as well as microwave dielectric performances were all investigated. The main phase of Li₃TiO₃F with cubic structures accompanied with small amounts of the LiF or Li₂TiO₃ secondary phase was identified by XRD analysis. SEM analysis showed that a uniform and dense microstructure was obtained for 750 °C-sintered samples. The dielectric constant (ε_r) and quality factor (Q × f) were found to be strongly correlated with porosity and grain size distribution, whereas the temperature coefficient of resonance frequency (τ_f) was mainly dominated by the phase assemblages. In particular, the 750 °C-sintered Li₃TiO₃F samples exhibited good microwave dielectric performances: ε_r = 18, Q × f = 57,300 GHz (under 9.2 GHz), τ_f = −43.0 ppm/°C. [ABSTRACT FROM AUTHOR]