Application of Wagner's Theory to the Parabolic Growth of Oxides Containing Different Kinds of Defects: I . Pure Oxides

A generalized treatment of the parabolic oxidation of pure metals forming electronically semiconducting oxides containing different kinds of defects is developed by extending the Kröger approach to Wagner's theory of oxidation based on the analysis of the diffusion of lattice defects. Only oxides with defects in the cation sublattice are considered for simplicity. It is shown how the generally used expressions for the dependence of the parabolic rate constant and the self‐diffusion coefficient of the metal as functions of the oxygen activity through the scale are modified by the presence of more than one type of lattice defect. This treatment is then applied to the oxidation of cobalt in oxygen at 1000°C taking into account the actual defect structure of , obtaining a reasonable agreement with the experimental results.