Li4WO5: A temperature stable low-firing microwave dielectric ceramic with rock salt structure

A Li4WO5 ceramic with rock salt structure was prepared by the solid-state reaction method and its microwave dielectric properties was demonstrated for the first time. It could be well densified at relatively low sintering temperature (∼890 °C). XRD and DTA analysis revealed a phase transformation from cubic to orthorhombic occured at 700 °C. Excellent microwave dielectric properties with a near-zero temperature coefficient of resonant frequency ∼−2.6 ppm/°C, a relative permittivity ∼8.6 and a quality factor ∼23,100 GHz (at 11.0 GHz) was obtained. Li4WO5 was found to be chemically compatible with silver powders when sintered at 890 °C. All the results indicate that the Li4WO5 ceramic is a promising candidate as a base material in low temperature cofired ceramic technology.