Phase-transition kinetics of silicon-doped titanium dioxide based on high-temperature X-ray-diffraction measurements

Titanium dioxide (TiO2) is widely used as a pigment, additive in food, and personal care. The properties and applications of titanium dioxide vary with crystal structure. In this study, in situ high-temperature X-ray diffraction was used to examine the effect of silicon doping on the phase-transition kinetics of titanium dioxide. Transformation from anatase to rutile titanium dioxide was observed in real time; the Rietveld method was used to calculate the rutile content. The first-order kinetic and Johnson-Mehl-Avrami-Kohnogorov models were compared; the latter was in better agreement with the data. The experimental results showed that the crystal growth process was controlled by the growth of the interface. The phase-transition temperatures for samples with 0%, 5%, and 7.5% silicon were 600, 620, and 630 ​°C, respectively; the activation energies were 212.3, 228.0, and 293.9 ​kJ/mol, respectively. This increase in phase transition temperature and activation energy indicates that doping with silicon inhibits the transformation of anatase to rutile titanium dioxide.