Investigation of grinding effects in binary mixtures from the TiO2-SnO2-V2O5 system

Solid solution formation induced by dry ball-milling under an argon atmosphere has been investigated in binary mixtures from the TiO2-SnO2-V2O5 system mainly by X-ray diffraction and differential scanning calorimetry, Grinding experiments followed by heat treatments result in substantial solid solubilities in all three binaries, Under our experimental conditions, the solubility after grinding depends solely on the nature of grinding media particularly in V2O5 based systems, when reduction reactions take place between grinding tools and oxide particles. The results demonstrate that the interaction between TiO2 or SnO2 and V2O5 follows from the fact that SnO2 and TiO2 are first slightly reduced during milling and subsequently reoxidized by V2O5. These interactions promote solid solution formation and the development of a reduced disordered vanadium oxide layer at the surface of SnO, grains. The final state of powders, where the interface density between both oxides is very high, could be of interest in catalysis. (C) 1996 Academic Press, Inc.