Novel 5MgO-3Li2O-4WO3 ceramic: preparation, phase evolution and its microwave dielectric properties

A new low-temperature firing microwave dielectric ceramic with the composition of 5MgO-3Li(2)O-4WO(3) was synthesized by a solid-state reaction method. The ceramic was found to be a novel pure compound (Li2Mg2W2O9) when the sintering temperature was 720-760 degrees C, but transformed to mixed phases with Li2Mg2W2O9 and Li2WO4 when the sintering temperature was 820-840 degrees C. The ceramic sintered at similar to 820 degrees C exhibited good properties with relative permittivity of similar to 10.3, Q x f value about 20,537 GHz (at the frequency f similar to 11 GHz) and a negative temperature coefficient of resonant frequency of -76.9 ppm/degrees C. 5MgO-3Li(2)O-4WO(3) ceramic had a promising application in low-temperature cofired ceramic technology.