Enhancement of densification and microwave dielectric properties in LiF ceramics via a cold sintering and post-annealing process

LiF is a low-firing fluoride with excellent microwave dielectric properties, however densification of ceramics challenging owing to their low surface free energy. In this study, cold sintering process (150 °C, 250 MPa, 60 min) was employed pre-densify 78 % relative density. Post-annealing treatments between 650 °C and 800 led significant grain growth which accompanied by an increase in density 92 %. The quality factor ( Qf ) increased increasing annealing temperature maximum 110,800 GHz at 1.5 times higher than the value obtained via conventional (78,800 GHz), permittivity ? r = 8.2 coefficient resonant frequency, ? f =–135 ppm/°C. Such high values its compatibility Ag electrode suggest that sintered has great potential as component or additive co-fired ceramic formulations.