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–3Li2O–4WO3 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 °C, but transformed to mixed phases with Li2Mg2W2O9 and Li2WO4 when the sintering temperature was 820–840 °C. The ceramic sintered at ~820 °C exhibited good properties with relative permittivity of ~10.3, Q × f value about 20,537 GHz (at the frequency f ~ 11 GHz) and a negative temperature coefficient of resonant frequency of −76.9 ppm/°C. 5MgO–3Li2O–4WO3 ceramic had a promising application in low-temperature cofired ceramic technology.