Diffusion kinetics of indium in TiO2 (rutile)

This work determines the self-diffusion coefficients of indium in TiO 2 single crystal (rutile). Diffusion concentration profiles were imposed by deposition of a thin surface layer of InCl3 on the TiO2 single crystal and subsequent annealing in the temperature range 1073-1573 K. The diffusion-induced concentration profiles of indium as a function of depth were determined using secondary ion mass spectrometry (SIMS). These diffusion profiles were used to calculate the self-diffusion coefficients of indium in the polycrystalline In2TiO5 surface layer and the TiO2 single crystal. The temperature dependence of the respective diffusion coefficients, in the range 1073-1573 K, can be expressed by the following formulas: DIn-In2TiO5=1. 9×10-13exp(-142kJ/mol/RT)[m2s-1] and DIn-TiO2=7.4×10-4exp(-316kJ/mol/RT) [m2s-1] The obtained activation energy for bulk diffusion of indium in rutile (316 kJ/mol) is similar to that of zirconium in rutile (325 kJ/mol). The determined diffusion data can be used in selection of optimal processing conditions for TiO2-In2O3 solid solutions.