The Interaction of Zirconia with Oxygen and Its Defect Structure

The mass action law is used to describe the reversible exchange between the crystal lattice of $\text{ZrO}_2$ and the ambient medium, and the special features of positioning of interstitial particles in the lattice are taken into account. The ways of equilibrium interaction between the $\text{ZrO}_{2-x}$ lattice with the ambient medium (types of defects that arise) at different partial pressures of oxygen $p(\text{O}_2)$ and temperatures $T$ are determined, along with the form of the correlation $x = f[p(\text{O}_2)]$, the variation of its composition, the number of charge carriers, mass, volume, and density. The obtained results are compared with the available experimental data. It is demonstrated that, at low temperatures, the lattice defects in pure $\text{ZrO}_2$ are as follows: at high values of $p(\text{O}_2)$ – oxygen vacancies in the anion sublattice and singly charged anions of oxygen in the interstice, and at low values of $p(\text{O}_2)$ – vacancies in the anion sublattice and electrons localized on the adjacent cations. At high temperatures, the lattice defects are as follows: at high values of $p(\text{O}_2)$ – singly charged anions of oxygen and quadruply charged cations of zirconium at the interstice, and at low values of $p(\text{O}_2)$ – only neutral zirconium atoms at the interstice.