Effect of preparation methods on microstructures and microwave dielectric properties of Ba(Mg1/3Nb2/3)O3 ceramics

Abstract

Effect of preparation methods on microstructures and microwave dielectric properties of Ba(Mg1/3Nb2/3)O3 ceramics was investigated. Ba(Mg1/3Nb2/3)O3(BMN) ceramics were prepared by the conventional mixed oxides method and the molten salt synthesis method. It was shown that the single-phase of BMN was obtained at 900 °C in the molten salt synthesis method. No single-phase BMN was obtained in the conventional mixed oxides method, although the calcining temperature was increased up to 1400 °C. BMN powders prepared by the molten salt synthesis method had better sinterability than that prepared by the conventional mixed oxides method. Because of the very different nature of the powders, different microstructures were observed. The molten salt synthesis method ceramics have a higher B-site ordering parameter (S) and larger grain size than that of the conventional mixed oxides ceramics at same sintering temperature. The variation of Qf, er and τf were also explained based on the difference in microstructures.