Effects of non-planar geometries and volumetric expansion in the modeling of oxidation in titanium

Development of a model for oxidation of titanium based upon diffusion of ox ygen in the oxide is presented in this work. Equations describing motion of the oxygen-oxide and metal-oxide interfaces are derived using jump mass ba lance. The volumetric expansion of the oxide and its impact on the motion o f interfaces is fully accounted for. An analytical solution is obtained for the case of one-dimensional planar oxidation and is used to estimate the d iffusion coefficient of oxygen into titanium dioxide. Numerical results are presented for the cases of oxidation on the surface of a cylinder, oxidati on of a cylindrical hole and oxidation of a sphere and comparisons are made with experimental data. (C) 2001 Elsevier Science Ltd. All rights reserved .