Kinetic Model for Nanocrystalline Anatase to Rutile Polymorphic Transformation

Abstract

In this paper, kinetic models are presented for phase transformation from anatase to rutile in nanocrystalline samples at different temperature ranges. The models, in which the nucleation and growth are considered together, are able to predict the polymorphic transformation behavior of titania with better accuracy. In addition to researchers' assumption that phase transformation of nanocrystalline anatase to rutile at lower temperatures occurs only with interface nucleation, the results reveal that the surface nucleation can also have a significant role in the kinetics of phase transformation in conditions of prolonged heating. In comparison to other published models, the advantage of these models is that no experimental data regarding the size of particles is required to study the kinetics of phase transformation of TiO 2 nanoparticles.