Temperature Stability of Li₂TiO₃‐Zn₂SiO₄ Microwave Dielectric Ceramics

Abstract

Abstract In this work, microstructure, composition, and microwave dielectric properties of nominal compositions (1‐ x )Li 2 TiO 3 ‐ x Zn 2 SiO 4 ( x =0.1, 0.2, 0.3, 0.4), which were prepared by conventional solid‐state ceramic route, have been investigated. Li 2 TiO 3 and Zn 2 SiO 4 reacted to form Li 2 ZnSiO 4 and Zn 2 Ti 3 O 8 , where Zn 2 Ti 3 O 8 is formed during Zn 2 TiO 4 cooling. The microwave dielectric properties of samples are mainly affected by the characteristics and relative content of crystal phase and densification. With the increase of x , the relative dielectric constant (ϵ r ) decreases gradually. The quality factor (Qf) value increases at first, reaches the maximum value at x =0.2, and then decreases. The temperature coefficient of resonance frequency (τ f ) value has a sharp decrease due to the increase of Li 2 ZnSiO 4 . A near zero τ f of about −2.0 ppm/°C was obtained in 0.8Li 2 TiO 3 –0.2Zn 2 SiO 4 ceramic sintered at 1150 °C for 4 h with ϵ r value of 17.67, Qf value of 19,600 GHz. Thus, it could be a candidate for microwave devices.