Processing, phase analysis and microwave dielectric properties of Sr5−xBixTi1+xNb4−xO17 (x\u2009=\u20094, 3) ceramics

Abstract

The ceramics in Sr5−xBixTi1+xNb4−xO17 (x\u2009=\u20094, 3) series were prepared using solid state sintering method. The phase and microwave dielectric properties were investigated. The parent phase Sr2Bi3Ti4NbO17 and SrBi4Ti5O17 phases did not formed along the Sr5−xBixTi1+xNb4−xO17 series for the compositions with x\u2009=\u20093 and 4. The SrBi4Ti4O15 phase formed as the major phase along with some secondary Bi2Ti2O7 and SrTiO3 phases for the composition with x\u2009=\u20094 in Sr5−xBixTi1+xNb4−xO17 series. For the composition with x\u2009=\u20093 in Sr5−xBixTi1+xNb4−xO17 series, Nb based Bi2Ti2O7 pyrochlore phase formed as the major phase along with SrBi3Ti2NbO12 phase as a secondary phase. In this study, good combination of microwaves dielectric properties i.e., εr\u2009~\u2009166, Qufo 8888 GHz and τf\u2009~\u20093.4 ppm/°C is obtained for the compositions with x\u2009=\u20094 sintered at 1200 °C and εr\u2009~\u200988, Qufo~\u200912,500 GHz and τf\u2009~\u2009−\u20099.36 ppm/°C is obtained for the composition with x\u2009=\u20093 sintered at 1200 °C.