A brief review was presented of the experimental data available on ionic oxides, and the problems involved in their interpretation. Fundamental differences between grain boundary diffusion in metals and ceramics were noted. Calculations of the segregation of defects and impurities to grain boundaries were described, together with methods for calculating diffusion coefficients in these boundaries. New results were presented for alumina and chromia. The problem of defining grain-boundary width was considered with respect to new calculations on nickel oxide.

Short-Circuit Diffusion in Ceramics. J.H.Harding: Interface Science, 2003, 11[1], 81-90