Phase-transition kinetics of calcium-doped TiO2: A high-temperature XRD study

Controlling titanium dioxide crystallinity is crucial in view of the possible oxide applications. In this study, we examined the effects of calcium doping on the anatase-rutile phase transition via in-situ high-temperature X-ray diffraction. The phase transition temperature of calcium-doped TiO2 was approximately 900 degrees C, specifically 900 degrees C, 875 degrees C, and 900 degrees C for the 2%, 4%, and 6% calcium-doped TiO2, respectively. The larger radius of the calcium ion compared to that of the titanium ion hindered the calcium incorporation into the TiO2 lattice. Moreover, the hampered titanium-oxygen bond rotation during the phase transition led to an increase in the phase-transformation temperature. Furthermore, at higher calcium concentrations, the corresponding activation energies increased first and then decreased. This may have been controlled by the decreasing nucleation rate during the reaction.

Automated summary

Controlling the crystallinity of titanium dioxide is important for its potential applications. In this study, the effects of calcium doping on the anatase-rutile phase transition were investigated using in-situ high-temperature X-ray diffraction. The results showed that calcium doping increased the phase transition temperature and reduced the activation energy.