Li2Zn3Ti4O12–Ba3(VO4)2 microwave dielectric ceramics sintered at a low temperature without glass addition

Abstract

The microstructure and microwave dielectric properties of the (1−x)Li2Zn3Ti4O12–xBa3(VO4)2 composite ceramics prepared via a solid-state reaction method have been investigated systematically by using an X-ray diffractometer (XRD), a scanning electron microscope equipped with an energy dispersive spectrometer and a microwave network analyzer. The XRD results exhibited that the Li2Zn3Ti4O12 and Ba3(VO4)2 ceramic could coexist well in the sintered bodies, and no other secondary phase was detected. The microstructure and microwave dielectric properties of the composite ceramics were found to be obviously dependent on the sintering temperature and phase composition. With the addition of the Ba3(VO4)2 phase, the sintering temperature of the Li2Zn3Ti4O12 ceramic could be reduced effectively and its temperature coefficient of resonant frequency (τf) value could also be adjusted to near zero together with a comparable quality factor (Q × f) value. Excellent microwave dielectric properties of dielectric constant er ~ 16.9, Q × f ~51,322 GHz and τf ~+3.3 ppm/°C were obtained in the 0.4Li2Zn3Ti4O12–0.6Ba3(VO4)2 composite ceramic, when sintered at 950 °C for 4 h. The good chemical compatibility between the 0.4Li2Zn3Ti4O12–0.6Ba3(VO4)2 composite ceramic and silver electrode indicates that the as-prepared composite ceramic is suitable for low-temperature cofired ceramic (LTCC) applications.