Specific features of oxygen-ionic conduction in oxide nanoceramics

The effect of surface tension on the activation energy for oxygen-ionic conduction in nanoceramics is considered. The activation energy is calculated for oxygen ion diffusion through oxygen vacancies, which are treated as dilatation centers. The activation energy is shown to decrease as the nanoparticle size decreases. Based on the size distribution function of nanoparticles, the activation energy distribution function is calculated. Analytical expressions are obtained for the dependences of the ionic conduction on temperature and nanoparticle size. The increase of two to three orders of magnitude in the oxygen-ionic conduction observed earlier in the ZrO₂: 16% Y nanoceramics is adequately described by these expressions. The surface tension of nanoparticles is shown to cause a substantial increase in the oxygen-ionic conduction observed in nanoceramics; the main contribution to the conductivity is related to a region near the particle surface.