The effect of aliovalent dopants on the kinetics of phase separation in the TiO2-SnO2 system was examined. Cation diffusion coefficients were estimated from the kinetics of phase transformation assuming transformation to be diffusion-controlled. Divalent and trivalent cation dopants accelerated while pentavalent dopants suppressed the kinetics of phase transformation. Independent measurements also showed that trivalent dopants enhanced and pentavalent dopants suppressed interdiffusion coefficients.

The Effect of Aliovalent Dopants on Cation Diffusion in TiO2-SnO2. Drobeck, D.L., Virkar, A.V., Cohen, R.M.: Journal of Physics and Chemistry of Solids, 1990, 51[8], 977-88