Phase stability in the nanocrystalline TiO₂ system

Initial thermodynamic analysis predicts surface tension of fine solid particles decreases with decrease in particle size. Free energy of fine solid particles increases with decrease in particle size. In the nanocrystalline TiO₂ system, the surface tensions and the surface energies of both anatase and rutile were estimated by modeling available thermochemical data and kinetic data. The particle size versus temperature phase diagram of the nanocrystalline TiO₂ system was calculated, which reveals 1-8 nm anatase is more stable than rutile of the same size at certain temperatures.