SYNTHESIS AND FERROELECTRICAL PROPERTIES OF LEAD TITANATE PARTICLES BY HYDROLYSIS AND CONDENSATION OF COMPLEX ALKOXIDE IN OCTANOL ACETONITRILE SOLUTIONS/

An attempt was made to produce lead titanate particles with a sol-gel process which adopted the hydrolysis and condensation reactions of com plex alkoxide prepared from Pb (O-i-C3H7)(2) and Ti(OC2H5)(4). The syn thetic reactions of the complex alkoxide were carried out in octanol f or 2-72h at 70 degrees C, and the successive hydrolysis and condensati on reactions were performed at water concentrations of 0.1-2.3 mol/dm( 3) at an ambient temperature in octanol-butanol solvents containing ac etonitrile as a cosolvent. Size distributions of the lead titanate par ticles formed were measured with dynamic light-scattering. Selection o f reaction conditions enabled the synthesis of spherical particles wit h average diameters less than 100 nm in ranges of water concentrations of 0.5-2.0 mol/dm(3) and acetonitrile concentrations of 15-20 vol% at a total monomer concentration of 0.05 mol/dm(3). The particles were s ubjected to heat treatment at various temperatures. The particles star ted to crystallize into a tetragonally perovskite structure at 200 deg rees C, and transformed into a single phase at 750 degrees C. Dielectr ic constants of the particles heat-treated at 500-750 degrees C were c lose to that of bulk, whereas the crystallite sizes in the particles w ere similar to the sizes of the particles produced in the reactions.