INVESTIGATION OF GRINDING EFFECTS IN BINARY-MIXTURES FROM THE TIO2-SNO2-V2O5 SYSTEM

Solid solution formation induced by dry ball-milling under an argon at mosphere has been investigated in binary mixtures from the TiO2-SnO2-V 2O5 system mainly by X-ray diffraction and differential scanning calor imetry, Grinding experiments followed by heat treatments result in sub stantial solid solubilities in all three binaries, Under our experimen tal conditions, the solubility after grinding depends solely on the na ture of grinding media particularly in V2O5 based systems, when reduct ion reactions take place between grinding tools and oxide particles. T he results demonstrate that the interaction between TiO2 or SnO2 and V 2O5 follows from the fact that SnO2 and TiO2 are first slightly reduce d during milling and subsequently reoxidized by V2O5. These interactio ns promote solid solution formation and the development of a reduced d isordered vanadium oxide layer at the surface of SnO, grains. The fina l state of powders, where the interface density between both oxides is very high, could be of interest in catalysis. (C) 1996 Academic Press , Inc.