A mechanistic study of TiO2 anatase-to-rutile phase transformation under mechanical processing conditions

A systematic investigation on the mechanistic features of the anatase-to-rutile phase transformation under mechanical treatment conditions has been performed. Mechanical processing was carried out first on pure anatase powders and was demonstrated to induce two consecutive transformations from anatase to TiO2 II and from this to rutile. Phase transformation kinetics was described by means of kinetic curves and the rate quantified by two rate constants. The mechanical treatment was successively performed on anatase–rutile powder mixtures with different rutile contents. Being the final product of phase transformations, rutile acts here as an inert phase. Its effect on rate constants was carefully ascertained and used to further point out their physical meaning.