Effects of lithium fluoride addition on sintering characteristics and microwave dielectric properties of rock–salt structure Li2Mg4TiO7 ceramics

Li2Mg4TiO7 ceramics doped with 1–5 wt% LiF were successfully prepared by the conventional solid-state method. The sintered samples could be well indexed as the rock salt structure with space group Fm-3m (JCPDS #70-2711). The sintering behaviors, phase compositions, microstructures and microwave dielectric properties of ceramics were associated with the sintering temperature and the amount of LiF addition. The εr and Q·f values of the Li2Mg4TiO7 ceramics increased firstly and then decreased with increasing the amount of LiF addition. A near zero temperature coefficient of resonant of frequency (τf ) value could be obtained by adjusting the amount of LiF additions. The Li2Mg4TiO7 ceramics doped with 2 wt% LiF sintered at 950 °C for 4 h possessed promising microwave dielectric properties with εr value of 14.43, Q·f value of 48,700 GHz and τf value of −3.83 ppm/°C, making them suitable for low-temperature co-fired ceramic applications.