Sonochemically activated solid-state synthesis of BaTiO3 powders

Sonochemical activation in aqueous medium for solid-state synthesis of BaTiO3 powders

“…In our previous study, we showed that sonochemical activation, even in ethanol, could accelerate the solid-state reaction by the effect of particle size reduction through the preferential fragmentation of BaCO 3 [35] . In this experiment, the phase conversion (95.7–98.2% using ethanol) could be further enhanced by using aqueous medium (97.2–99.8%) for the sonochemical activation, implying that there is an additional chemical effect of the aqueous medium on the solid-state reaction, as marked by the colored arrows in Fig.…”

“…Furthermore, all ultrasonicated BaCO 3 in the aqueous medium exhibited a smaller particle size than that in ethanol (∼2.9 μm). In our previous study, we performed the sonochemical activation of BaCO 3 in ethanol [35] . In that case, only mechanical fragmentation was attributed to the particle size reduction of the BaCO 3 .…”

“…It is known that the size reduction owing to the ultrasonication can be attributed to mechanical fragmentation and chemical dissolution [24] , [33] , [34] , [35] , [37] . To verify the effect of pH on the dissolution of BaCO 3 , ICP measurements for the supernatant of 600 W ultrasonicated medium were performed.…”

“…Because of its high calcination temperature (∼1200 °C), solid-state reaction can provide highly dense BaTiO 3 powders, which is desirable in terms of reliability. Furthermore, it has been reported that submicron-sized BaTiO 3 powders can be successfully prepared via the solid-state reaction through appropriate pre-treatments of the raw materials, such as high-energy ball-milling and mechanochemical [29] , [30] , [31] , [32] and sonochemical activation [33] , [34] , [35] . These pre-treatments result in downsizing and uniform mixing of the raw materials, thereby facilitating the synthesis of BaTiO 3 powders through reaction (1).…”

“…Among these pre-treatment methods, sonochemical activation, which uses ultrasonication for the downsizing and mixing of raw materials, is a contamination-free, time-saving, and cost-effective process. Recently, we reported that sonochemical activation of BaCO 3 and TiO 2 in ethanol could significantly enhance the solid-state process for the synthesis of BaTiO 3 powders (∼200 nm) at a relatively low temperature (∼1000 °C) [35] . This was mainly attributed to the physical effect of the ultrasonic irradiation, i.e., the preferential fragmentation of BaCO 3 .…”