Models for diffusion with trapping effects

Many models have been proposed to explain the effect of traps on interstitial diffusion. Some models are very general but either require extensive use of a computer or the expressions for the diffusion coefficient are too involved. These models, therefore can not be easily compared with experimental data. Simple models may have conceptual limitations, however, they can sometimes provide a consistent description of the experimental data within their validity. The models proposed by Oriani, by McLellan, and by Perkins and Padgett are discussed and compared using experimental data for oxygen diffusion in niobium-based alloys