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

Abstract

The crystalline phases, microstructure, composition analysis and microwave dielectric properties of Li2TiO3–xvol.% Li2Zn3Ti4O12 (x=15–40) composite ceramics with 1–3wt.% 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 −1.3ppm/°C was obtained in the Li2TiO3–30vol.% Li2Zn3Ti4O12 ceramic sintered at 1100°C for 2h with permittivity of 22.0, Q×f value of 38,900GHz. The microwave dielectric properties of Li2TiO3–20vol.% Li2Zn3Ti4O12 ceramics with 1–3wt.% LZB glass addition sintered at 900°C for 2h were characterized. The addition of 2.5wt.% LZB glass reduced the sintering temperature of the Li2TiO3–20vol.% Li2Zn3Ti4O12 ceramic from 1100°C to 900°C without obvious degradation of the microwave dielectric properties. The 2.5wt.% LZB glass-added Li2TiO3–20vol.% Li2Zn3Ti4O12 ceramic sintered at 900°C for 2h could reach a high relative density of 98% of the theoretical density of the Li2TiO3–20vol.% Li2Zn3Ti4O12 ceramic and exhibited microwave dielectric properties of ɛr=22.0, Q×f=28,407GHz, and a near zero τf value of −1.6ppm/°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.