Studies on a basic question of zinc titanates

Anatase and rutile TiO2 crystalline powders were combined with ZnO powder to synthesize zinc titanates using traditional solid-state reaction method, on the basis of which, the disagreement between experimental results and the well-known hypothesis that the formation of Zn2TiO4 is limited by the presence of anatase whereas ZnTiO3 is formed only in the presence of rutile, a basic but unresolved question, was discussed qualitatively and phenomenologically by means of X-ray diffraction and thermal analysis. On the one hand, a grain size effect of anatase powder on the amount of ZnTiO3 product was found out in ZnO-TiO2 system for the first time, and can well explain the appearance of ZnTiO3 in anatase-derived zinc titanates. On the other hand, a so-called RID process was put forward to interpret the appearance of Zn2TiO4 in rutile-derived zinc titanates calcined at temperatures below the onset decomposition temperature of ZnTiO3, and agreed well with the experimental results. As a result, the reasons for the disagreement mentioned above were naturally exposed, and a key factor in the achievement of pure or, at least a higher mass fraction of ZnTiO3 under solid-state conditions as well. (C) 2008 Elsevier B.V. All rights reserved.