摘要
This paper describes the solid-state production of a unique yellowish-grey microwave dielectric ceramic,Ca_(3)Fe_(2)Ge_(3)O_(12)(CFG).Rietveld refinement demonstrated that CFG corresponds to a cubic system(space group 230:Ia 3 d).The relative density of the ceramic initially increased and then decreased with the sintering temperature,reaching a maximum of 96.92%at 1330℃.According to scanning electron mi-croscopy and energy-dispersive spectroscopy results,the CFG ceramic grains are spherical and consistent in size;furthermore,they have distinct grain boundaries and a uniform distribution of the four con-stituent elements.The CFG ceramic has a superior crystal structure and a high crystallinity,according to transmission electron microscopy.Raman spectroscopy revealed that the Q×f value of the ceramic and the full width at half maximum of the Raman peak are negatively correlated.The ceramic possesses the best overall dielectric characteristics after sintering at 1330℃for 4 h:ε_(r)=10.31,Q×f=82636 GHz,andτ_(f)=-45.66×10^(-6)℃^(-1),showing that it is a promising candidate for use in mobile devices.
基金
supported by Natural Science Foundation of China(Grant Nos.61761015,11664008)
Natural Science Foundation of Guangxi(Grant No 2018GXNSFFA050001)
the High Level Innovation Team and Outstanding Scholar Program of Guangxi Institutes.
