HYDROTHERMAL SYNTHESIS OF PBO-TIO2 SOLID-SOLUTION

The reactions between PbO and TiO2 in the PbO-rich side of the system PbO-TiO2 were investigated under hydrothermal conditions. The influences of Pb/Ti ratios (1.0-4.0) in the feedstock, reaction temperature (100-160-degrees-C), and pH (11.4-14.2) in the reaction medium on the reaction products have been researched. A new type of PbO-TiO2 solid solution [PT(SS)] can be formed under specific hydrothermal conditions. The Pb/Ti ratio in PT(SS) may be varied within a certain range. The PT(SS)-1 with a tabular morphology and a tetragonal structure is a typical PbO-TiO2 Solid solution that is preferentially formed. Its cell parameters are a = 3.911 angstrom and c = 4.831 angstrom, and its composition is PbTi-xO1+2x (x = 0.80 +/- 0.02). The PT(SS) is converted into the tetragonal perovskite-type PbTiO3 and PbO (litharge or massicot) over 550-degrees-C. A combination of heat treatment and acetic acid wash of PT(SS) could provide a new method for preparing ultrafine PbTiO3 powders.