Effect of Ba5Ta4O15 incorporation on sintering behavior and microwave dielectric properties of Ba(Ma(1/3)Ta(2/3))O-3 materials

The characteristics of Ba(Mg1/3Ta2/3)O-3 BMT materials synthesized by a two -step process, consisting of the formation of B-site compounds, e.g., MgTa2 O6, followed by the formation of a BMT perovskite, were compared with the p roperties of BMT powders-prepared by the conventional single-step mixed-oxi de route. BMT powders prepared by the two-step process exhibits superior re activity compared to those synthesized by the single-step process. The sing le-phase perovskite can be formed at a lower calcination temperature (900 d egrees C) and high density ceramic materials can be obtained at a lower sin tering temperature with a short period of time (1500 degrees C, 2 h). When the Ba5Ta4O15 is incorporated into pure BMT perovskite, the sintered densit y of BMT materials decreases significantly, and the dielectric constant (K) and temperature coefficient of resonance frequency (tau(f)) are not altere d significantly, but the Q-factor of the BMT materials decreases significan tly. These observations imply that the mechanism by which the two-step proc ess significantly improves the densification process and the related microw ave dielectric properties is the effective suppression of formation of the secondary phase, Ba5Ta4O15.