Hyperfine characterization of the metastable t"-form of the tetragonal phase in ZrO2-10 mol % Y2O3 powders synthesized by gel combustion

A nanocrystalline ZrO2-10 mol% Y2O3 powder synthesized by a nitrate-citrate gel-combustion process and stabilized in the metastable t"-form of the tetragonal phase has been characterized using mainly the Perturbed Angular Correlations technique. The determined hyperfine interaction allows a clear distinction between the zirconium surroundings in the t"-form and those already known of the other forms of the tetragonal phase. Oxygen vacancies movement is revealed as a slow diffusion involving a very small activation energy. As the powder is heated, a transformation is observed to occur around 560 degrees C, which is consistent with a C-to-cubic transition.