The effect of diameter ratio between transducers and reactor in sonication-assisted synthesis of Ba_0.7Sr_0.3TiO₃ and Ba_0.3Sr_0.7TiO₃ nanoparticles

This paper describes the particle size characterization of mechanically alloyed Ba_0.7Sr_0.3TiO₃ and Ba_0.3Sr_0.7TiO₃ prepared with the aid of a high-power ultrasonic destruction. Analytical-grade BaCO₃, TiO₂ and SrCO₃ with a purity greater than 99 wt.% were used as precursors for Ba_0.7Sr_0.3TiO₃ and Ba_0.3Sr_0.7TiO₃. The mechanically powders were respectively sintered at 1200 °C for 3 hours to form crystalline powders. This work is aimed at studying the effect of diameter ratio between reactor and transducer of a high power sonicator on the Ba_0.7Sr_0.3TiO₃ and Ba_0.3Sr_0.7TiO₃ nanoparticles formation. The presence of a single phase of the two materials was confirmed by X-Ray Diffraction (XRD). The concentration of the particles in demineralized water was 3.0 g / 100 mL which become the object of 3 hours ultrasonic destruction subjected to the application of transducer in which the ratio between the diameter of the reactor and the transducer (D/d) was fixed at 1.4, 1.6 and 1.8 respectively. It was found that the mean particle size before the ultrasonic destruction was 538 nm for Ba_0.7Sr_0.3TiO₃ and 480 nm for Ba_0.3Sr_0.7TiO₃. With D/d of 1.8, the mean particle size of the two materials was found to decrease drastically to 38 nm and 24 nm, respectively. These mean particle sizes were respectively comparable with that of the crystallite size of the particles derived using the Whole Powder Pattern Modelling (WPPM) from which the mean crystallite size of 22 nm for Ba_0.7Sr_0.3TiO₃ and 14 nm for Ba_0.3Sr_0.7TiO₃ were obtained. It is then confirmed single nanocrystallite Ba_0.7Sr_0.3TiO₃ and Ba_0.3Sr_0.7TiO₃ particles were already achieved. We can conclude that the ultrasonic destruction to mechanically milled crystalline particles would be one of an effective way to produce nanoparticles.