Preparation and characterization of mixed oxides obtained from various molar mixtures of beta-PbO2 and TiO2

A detailed physical characterization of various mixed oxides obtained from 75 : 25, 65 : 35, 60 : 40, 50 : 50, 40 : 60, 35 : 65 and 25 : 75 molar mixtures of beta-PbO2 and TiO2 through solid state reaction has been made by using various analytical techniques like X-ray diffraction, UV-visible reflectance, scanning electron microscopy with energy dispersive X-ray analysis, spin resonance spectroscopy and X-ray photoelectron spectroscopy. These studies reveal that the mixed oxides contain two phases: PbTiO3 with Pb1-xTixO and PbTiO3 with Ti1-xPbxO2 at the PbO2-rich and the TiO2-rich side of the PbO2-TiO2 system respectively. The 50 : 50 molar mixture produces a single phase PbTiO3 compound. It is also observed that incorporation of Ti into the PbO lattice restricts the phase transformation of tetragonal PbO to orthorhombic PbO on the PbO2-rich side of the system and incorporation of Pb into the TiO2 lattice makes the Pb4+ state stable even at high temperatures, in the TiO2-rich region of the system.