Effects of Zn non-stoichiometry on the phase evolution and microwave dielectric properties of Li_2Zn_(1-x)Ge_3O_8 (0 < x < 0.2) spinels

摘要

A series of Li_2Zn_(1-x)Ge_3O_8 (0≤x≤0.2) spinels were prepared by the conventional solid-state reaction. The phase composition and microstructure were investigated using X-ray diffraction, Raman spectroscopy and scanning electron microscope. The microwave dielectric properties of samples were observed strongly dependent on the sintering temperature and composition. Li_2Zn_(1-x)Ge_3O_8 (0≤x≤0.2) ceramics were well densified at 950℃ for 4 h and the best microwave dielectric properties were achieved at x = 0.15 with ε_r=8.7, Qxf= 99,600 GHz (at 15.0 GHz), and τ_f = —60.1 ppm/℃. Furthermore, the chemical compatibility with the silver electrode were confirmed for Li_2Zn_(1-x)Ge_3O_8 ceramics. These ceramics could be possible candidates as LTCC materials.