Formation mechanisms and morphological changes during the hydrothermal synthesis of BaTiO3 particles from a chemically modified, amorphous titanium (hydrous) oxide precursor

The formation mechanism of BaTiO3 under hydrothermal conditions was investigated. A coprecipitated precursor prepared from chemically modified titanium isopropoxide with acetylacetone and barium acetate was used as a starting material. A solid-state kinetic analysis, supported by microstructural evidence, indicates that the formation mechanism of BaTiO3 in the current material system is dissolution and precipitation. The Ba-Ti complex gel dissolves into the aqueous soluble species, followed by direct precipitation from supersaturated solution. It is proposed that crystallization is controlled by dissolution of the hydrous Ti gel at the initial stage and then possibly by dissociation of the acetylacetonate group from the Ti solution species in which the acetylacetonate group is strongly bound to Ti. (C) 2003 Elsevier Science Ltd. All rights reserved.