Defect structure modification in zirconia by alumina

To high purity 8 mol% Y2O3 doped ZrO2, 0-0.6 mol% Al2O3 were added. The mic rostructures were characterized by SEM, and the electrical properties were measured by impedance spectroscopy. The bulk resistivity increases with inc reasing Al2O3 content, the grain boundary resistivity and the grain boundar y thickness also increase with increasing Al2(O)3 content, which is mainly due to the decreasing concentrations of free oxygen vacancies in the bulk a nd at the grain boundaries as a result of the Al2O3 addition. Possible conc entration variations of the other defects, e.g. Y'(Zr), Al'(Zr), (Y'V-Zr(O) . .)(. .), (Al'V-Zr(O). .)(.), (Y'(ZrVOY)-Y-. .'(Zr))(x) and (Al'(ZrVOAl)-A l-. .'(Zr))(x) in the bulk and at the grain boundaries are also suggested.