A new temperature stable microwave dielectric ceramic with low-sintering temperature in Li2TiO3-Li2Zn3Ti4O12 system

The crystalline phases, microstructure, composition analysis and microwave dielectric properties of Li2TiO3-x vol.% Li2Zn3Ti4O12 (x = 15-40) composite ceramics with 1-3 wt.% Li2O-ZnO-B2O3 (LZB) glass addition prepared by solid-state reaction method have been investigated. A near zero temperature coefficient of resonant frequency (τf) of about −1.3 ppm/°C was obtained in the Li2TiO3-30 vol.% Li2Zn3Ti4O12 ceramic sintered at 1100 °C for 2 h with permittivity of 22.0, Q × f value of 38,900 GHz. The microwave dielectric properties of Li2TiO3-20 vol.% Li2Zn3Ti4O12 ceramics with 1-3 wt.% LZB glass addition sintered at 900 °C for 2 h were characterized. The addition of 2.5 wt.% LZB glass reduced the sintering temperature of the Li2TiO3-20 vol.% Li2Zn3Ti4O12 ceramic from 1100 °C to 900 °C without obvious degradation of the microwave dielectric properties. The 2.5 wt.% LZB glass-added Li2TiO3-20 vol.% Li2Zn3Ti4O12 ceramic sintered at 900 °C for 2 h could reach a high relative density of 98% of the theoretical density of the Li2TiO3-20 vol.% Li2Zn3Ti4O12 ceramic and exhibited microwave dielectric properties of ɛr = 22.0, Q × f = 28,407 GHz, and a near zero τf value of −1.6 ppm/°C. Moreover, this ceramic has a chemical compatibility with Ag electrode, making it a very promising candidate material for Low-temperature co-fired ceramic (LTCC) applications.