IMF2017

In this work, two direct synthesis methods; sonochemical and surface active etching method, are proposed as a simple way to achieved BaTiO₃ nanoparticles. In the sonochemical process, the oxides of perovskite BaTiO₃ were synthesized successfully without a calcination step. Synthesis parameters detailed exploration considering the role of sodium hydroxide (NaOH) concentration, synthesis atmosphere, ultrasonic reaction time and precursor concentration on the perovskite phase formation and particle size was presented. It was found that nanocrystals were formed directly before being oriented and aggregated into large particles in aqueous solution under ultrasonic irradiation. The nucleation in the sonocrystallization process was accelerated by the implosive collapse of bubbles, while the crystal growth process was inhibited or delayed by shock waves and turbulent flow created by ultrasonic radiation. A pure complex perovskite phase of spherical shape was formed completely in a short irradiation time without the calcination process. In the surface active etching process, the micrometer-sized BaTiO₃ precursor was converted successfully to nanometer-sized particles, and its irregular shape changes to nearly uniform spheres, with accurate stoichiometric control. The effects of temperature and time on surface active etching process is provided deeper insights into the mechanism and offers an important role to control the particle sizes more precisely. Experimental procedures revealed a possible process mechanism observed within the etched surface and Oriented-attachment growth models, and this demonstrated approach could be used as an excellent platform for preparing ceramic nanoparticles. Both methods are highly recommended for the preparation of other functional materials with controlled morphology, size, size distribution, and composition.