Development of surface phases in Ba(Zn1/3Nb2/3)O3–Ba(Ga1/2Ta1/2)O3 microwave dielectric ceramics

Ceramics in the system Ba(Zn1/3Nb2/3)O3–Ba(Ga1/2Ta1/2)O3 (BZN–BGT) were prepared by the mixed oxide route. Powders were calcined at 1200 °C for 4 h and sintered at temperatures in the range 1300–1450 °C. Products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and wavelength dispersive spectroscopy (WDS) techniques. processing of the ceramics two secondary phases developed on the surfaces of the sintered ceramics as a result of Zn evaporation: Ba8Zn1Ta6O24 (816) and Ba4Nb5O15 (BN). On the basis of this analysis, ceramics having the compositions of the two secondary phases were prepared independently by the mixed oxide route. Both ceramics have a hexagonal structure; the 816 phase has space group of P63cm.