Low-temperature sintering and microwave dielectric properties of Li ₃MO₄ (M = Ta, Sb) ceramics

Both Li₃TaO₄ and Li₃SbO₄ ceramics were prepared via the solid state reaction method. With 1 wt.% B ₂O₃ addition, the sintering temperatures of both Li ₃TaO₄ and Li₃SbO₄ ceramics can be lowered to near 930 °C. The chemical compatibility of silver electrode and the low-firing ceramics has been considered, and the results showed that both the Li₃TaO₄ and Li₃SbO₄ ceramics are chemical compatible with Ag. Good microwave dielectric properties were obtained with permittivities of 14.1 and 10.3, quality factor Q_f values of 29,900 (at 12.4 GHz) and 14,600 GHz (at 13.5 GHz), and temperature coefficient of resonant frequency values of -48 and -28 ppm/°C for Li ₃TaO₄ and Li₃SbO₄ ceramics with 1 wt.% B₂O₃ addition, respectively.