The electrical conductivity of zircaloy oxide films

The electrical conductivity of Zircaloy-2, improved Zircaloy-2 and Zircaloy-4 oxide films has been measured using gold, copper and zirconium electrodes over the temperature range of 296-723 K. No notable discrepancies among the temperature dependence of electrical conductivity in the oxide films obtained from all electrodes were found. Depending on the activation behavior it is thought that the conductivity corresponds to the thermal excitation of electrons. The current-voltage characteristics of all oxide films show non-Ohmic behavior where the bulk current (electronic in nature) is associated with the Schottky and/or the Poole-Frenkel processes. On the basis of these results, it is concluded that the electron motion dominates the electrical conductivity of zircaloy oxide films. Therefore the slow-diffusing negative oxygen ions control the oxidation process of zircaloys. (orig.)