Abstract: In the ZrO₂ ceramic systems doped with different oxides (Y₂O₃, MgO and Al₂O₃), the electronic energy spectroscopy and local density of states were calculated by a
theoretical quantum chemical method, and compared with the behaviors of electronic and ionic conduction. The results showed that for the system doped with Al₂O₃,
the energy gap near the Fermi energy level becomes smaller, so that the electronic conduction increases; the binding energy between Al and O atom increases, which
enhances the energy for vacancy migrating, the ionic conduction decreases. On the contrary, the systems doped with Y₂O₃ show a large
ionic conduction, but a weaker electronic conduction. The effect of MgO is just between above two systems. The mentioned results agree with that of references and experiments.

Key words: zirconia, doping, conductivity, SCF--Xα--SW method