Lowered sintering temperature and modulated microwave dielectric properties in Mg2SiO4 forsterite via Ge substitution

Y In this work, a strategy was demonstrated to reduce the sintering temperature of Mg2SiO4 ceramics while keeping the macrostructure unchanged, through an appropriate amount of low melting point Ge substitution for B-site Si. A series of Mg2Si1-xGexO4 (x = 0.1-0.4) ceramics were prepared by a solid-state reaction method. Influences of Ge substitution on the sintering behavior, crystal structure, and microwave dielectric properties were studied. By comparison, the Ge-substituted samples could be effectively sintered at relatively lower sintering temperatures (similar to 1370 degrees C), which is more than 100 degrees C lower than the nominal Mg2SiO4. In addition, the optimum microwave dielectric performance was achieved in the sample with x = 0.4, with the relative density similar to 97%, the relative dielectric constant (epsilon(r)) of 7.2, the quality factor (Q x f) of 75,794 GHz, and the temperature coefficient of the resonance frequency (tau(f)) of - 41.2 ppm/degrees C. This compositional regulation provides a paradigm for improving the sintering characteristics of silicate.