Particle Size-Controlled and Characteristics of Hydrothermally Synthesized BaTiO3 Nanoparticles

The increasing demand for miniaturized and high-capacitance multi-layer ceramic capacitor (MLCC) requires BaTiO3 dielectric powders with precisely controlled particle size, uniform morphology, and stable ferroelectric crystallinity. In this study, BaTiO3 powders with different particle sizes were synthesized via a hydrothermal method by tailoring the precursor chemistry and organic additive conditions. Relatively coarse BaTiO3 particles were synthesized using anatase TiO2 and BaCl2⋅2H2O precursors in a 2 M NaOH aqueous solution, whereas fine BaTiO3 particles were prepared from amorphous TiO2 precipitated from titanium(IV) butoxide in the presence of Ba(OH)2⋅8H2O, diethylene glycol, and glycolic acid. Both reactions were performed at 210°C for 48 h under hydrothermal conditions. Field-emission scanning electron microscopy and particle size analysis showed that the average particle size was significantly reduced from approximately 152.6±27.3 nm to 38.6±5.8 nm by introducing the organic additives. X-ray diffraction confirmed the formation of single-phase perovskite BaTiO3, and Raman spectroscopy characterised BaTiO3 bands in fine particles. These results suggest that additive-assisted hydrothermal synthesis is a strategy for preparing size-controlled BaTiO3 nanopowders for MLCC dielectric applications.