Formation mechanism of barium Titanate nanoparticle aggregations

Abstract

A novel nanoparticle aggregation structure of barium titanate was obtained by the hydrothermal method. Powder X-ray diffraction (XRD) revealed that the aggregates crystallized in the cubic phase. The crystallization of the products became more significant with reaction progress. The growth characteristics of the aggregates was further confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), and electron diffraction (ED) spectroscopy. The aggregation was composed of many 5-8 nm nanoparticles by orientation attachment and we found that the ED patterns indicated a single-crystal property for the aggregates. The size of the aggregates was about 60 nm and they grew as the reaction continued. From the results of energy dispersive X-ray (EDX) spectroscopy analysis and kinetics modeling using the Johnson-Mehl-Avrami (JMA) equation, the diffusion nucleation of Ba2+ ion was found to be dominant during the early stages of aggregation formation. The growth process of "diffusion nucleation-orientation attachment" revealed the formation mechanism of barium titanate nanoparticle aggregations. © Editorial office of Acta Physico-Chimica Sinica.