Sintering behavior, phase structure and adjustable microwave dielectric properties of Li2O–MgO–nTiO2 ceramics (1 ≤ n ≤ 5)

Li2O–MgO–nTiO2 (1 ≤ n ≤ 5) ceramics were prepared by a solid state reaction method. The sintering behavior, phase evolution, microstructure and microwave dielectric properties of ceramics were investigated. With increasing n value, the microstructure of ceramics changed from a porous structure to the compact structure. Bulk density, relative permittivity (εr) and temperature coefficient of resonator frequency (τf) firstly increased, reached a max value and then decreased with increasing n values. Q × f value first decreased, then increased and finally decreased again. When n = 2, Li2O–MgO–2TiO2 systems presented good microwave dielectric properties with Q × f value of 44,914 GHz, εr of 20.8 and τf of −10.15 ppm/oC and low density of 3.33 g/cm3. When n = 3, Li2O–MgO–3TiO2 systems showed better comprehensive performances with sintering temperature of 1050 °C, Q × f value of 48,513 GHz, εr of 25.5, τf of 1.6 ppm/oC and low density of 3.40 g/cm3.