Continuous Production of BaTiO3 Nanoparticles by Hydrothermal Synthesis

Abstract

Continuous production of BaTiO3 fine particles was performed by hydrothermal synthesis using a flow reaction system. The effect of reaction temperature on particle size and its distribution was investigated. Aqueous 0.1 M TiO2 sols and 0.12 M Ba(OH)2 solutions were used as starting materials. The reaction temperature was in the range 300−420 °C, and the reaction pressure was constant at 30 MPa. The reaction time was varied from 0.1 to 40 s with a flow rate of 15 or 75 g/min. Characterizations of products were performed by X-ray diffractometry, scanning electron microscopy equipped with energy dispersion X-ray spectrometry, and transmission electron microscopy. The conversion of TiO2 into BaTiO3 was also evaluated. At 300 °C, the Ti conversion increased with the reaction time and achieved a 95% yield at 38 s. With the increase in temperature, both the Ti conversion and the crystallinity of BaTiO3 became high. With an increase in temperature from 300 to 380 °C, the average particle size of BaTiO3 decreased ...