Sintering, microstructure, thermal conductivity and microwave dielectric properties of xLiF-(1-x)MgO ceramics (x=0.03-0.10 mol) were investigated. The high density was obtained in the specimens of x≥0.06, i.e., 0.04 LiF-0.96 MgO in mol, whereas the amount of 0.03 mol LiF was insufficient to densify. From the result that the contact flattening in the sintered specimen was observed, the densification occurred through the liquid-phase sintering. The specimen of x=0.06 showed the highest room-temperature thermal conductivity. Relative density, thermal conductivity, dielectric constant, and quality factor (Q x f) of the specimen for x=0.06 sintered at 900°C for 4 h were 97.8%, 39.2 Wm-1K-1, 9.45, and 14,671 GHz, respectively.
