Structural investigation of mechanically activated nanocrystalline BaTiO<inf>3</inf> powders

Abstract

In this article, in order to obtain tetragonal nanocrystalline BaTiO 3, structural investigations of mechanically activated BaTiO 3 powder have been performed. A mercury porosimetry analysis and scanning electron microscopy method have been applied for determination of the specific pore volume, porosity and microstructure morphology of the samples. The lattice vibration spectra of nonactivated and activated powders, their phase composition, lattice microstrains and the mean size of coherently diffracting domains were examined by Raman spectroscopy and the X-ray powder diffraction method. The average crystal structure of obtained nanocrystalline powders, estimated from X-ray diffraction data, gave evidence of retained, but slightly sustained tetragonality of powders, even for particles as small as ∼30 nm. Raman spectroscopy also gave clear evidence for local tetragonal symmetries, in particular through the presence of a band at ∼307 cm-1. © 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.