The microscopic mechanism leading to stabilization of cubic and tetragonal forms of zirconia was analyzed by means of a self-consistent tight-binding model. Using this model, energies and structures of zirconia containing different vacancy concentrations were calculated, equivalent in concentration to the charge compensating vacancies associated with dissolved yttria in the tetragonal and cubic phase fields (3.2 and 14.4mol%, respectively). The model was shown to predict the large relaxations around an O vacancy, and the clustering of vacancies along the <111> directions, in good agreement with experiments and first principles calculations. The vacancies alone were shown to explain the stabilization of cubic zirconia, and the mechanism was analyzed.

A Stabilization Mechanism of Zirconia Based on Oxygen Vacancies Only. S.Fabris, A.T.Paxton, M.W.Finnis: Acta Materialia, 2002, 50[20], 5171-8