MICROSTRUCTURAL STUDY OF VANADIUM-TITANIUM OXIDE POWDERS OBTAINED BY LASER-INDUCED SYNTHESIS

Using laser-induced pyrolysis, powder samples of pure TiO2 and mixed o xides with different vanadium content were prepared and analyzed by XR D. The diffraction patterns were interpreted in microstructural terms by Fourier analysis of their peak profiles. The influence of vanadium on the phase transition was studied and the changes in the particle an d microstrain distributions obtained at different temperatures were an alyzed. There is an evident correlation between the initial microstrai n distribution in the Ti1-xVxO2 powder and the vanadium content. The s egregation of the V2O5 phase causes a strain reduction into the anatas e structure. We suggest that the previously observed lowering of the t ransition temperature for the anatase-to-rutile transformation in the presence of vanadium is due to distortions induced by this ion in the anatase structure. (C) 1994 Academic Press, Inc.