POINT-DEFECT CONCENTRATION RELAXATION AND CREEP TRANSIENTS IN BINARY OXIDES

In non-stoichiometric oxides (NiO, CoO, Cu-2 O...) two thermodynamic parameters (temperature T and partial pression of oxygen P-O2) are necessary in order to fix the population of point defects. When one of these two parameters (T or P-O2) is suddenly changed and a physical property is continuously recorded, a ''transient'' can be observed due to the diffusion of the point defects in order to reach the new thermodynamic equilibrium population. Many works have been devoted to the majority point defects (non-stoichiometry). In this paper we present an overview about the high temperature transitory plastic deformation which is related with the minority point defects.