Rapid formation of strontium lead titanate nanopowders by the sonochemical method

Strontium lead titanate Sr_1-xPb_xTiO₃ (SPT) nanopowders have been conveniently synthesized using the sonochemical method. A high intensity of ultrasound irradiation can induce the rapid formation of nanometer SPT particles. By controlling the molar ratio of Sr²⁺ and Pb²⁺, SPT nanopowders of different morphologies can be obtained. When x = 0, spherical nanopowders can be obtained. With an increase of the Pb²⁺ content, the shape of the obtained nanopowders becomes cubic. The results, obtained from X-ray diffraction, show that the microstructure of the SPT nanopowders also changes with the increase of the Pb²⁺ content at a given total initial concentration. The formation process of the SPT nanopowders under ultrasonic action goes through two steps. First is the formation of the titanium hydroxide gel through the hydrolysis of TiCl₄, and then the Sr²⁺ and Pb²⁺ are diffused to the titanium hydroxide gel surface. After this, they are combined with the titanium's hydrous nucleus to form the SPT nanoparticles under the effect of ultrasound.