Effect of Ba₅Ta₄O₁₅Incorporation on Sintering Behavior and Microwave Dielectric Properties of Ba(Ma_1/3Ta_2/3)O₃Materials

Abstract

The characteristics of Ba(Mg 1/3 Ta 2/3 )O 3 , BMT materials synthesized by a two-step process, consisting of the formation of B-site compounds, e.g. , MgTa 2 O 6 , followed by the formation of a BMT perovskite, were compared with the properties of BMT powders prepared by the conventional single-step mixed-oxide route. BMT powders prepared by the two-step process exhibits superior reactivity compared to those synthesized by the single-step process. The single-phase perovskite can be formed at a lower calcination temperature (900°C) and high density ceramic materials can be obtained at a lower sintering temperature with a short period of time (1500°C, 2 h). When the Ba 5 Ta 4 O 15 is incorporated into pure BMT perovskite, the sintered density of BMT materials decreases significantly, and the dielectric constant ( K ) and temperature coefficient of resonance frequency (τ f ) are not altered significantly, but the Q -factor of the BMT materials decreases signicantly. These observations imply that the mechanism by which the two-step process significantly improves the densification process and the related microwave dielectric properties is the effective suppression of formation of the secondary phase, Ba 5 Ta 4 O 15 .