Analysis of Phase Stability in Cubic Zirconia Solid Solutions by First Principle Molecular Orbital Method

Abstract

The electronic structure of various kinds of c-ZrO₂ solid solutions is calculated by a first principles molecular orbital method. It is found that the calculated partial density of states agrees well with the ELNES obtained from ZrO₂-8mol%Y₂O₃. From the calculation for ZrO₂-R₂O₃ system in which the effect of stabilization on c-ZrO₂ is high, the addition of R₂O₃ was found to remarkably decrease the repulsive Coulomb force between neighboring oxygen ions. In contrast, the addition of TiO₂, which has no effect to stabilize c-ZrO₂, increases the repulsive interaction between oxygen ions. It was concluded that the instability of c-ZrO₂ solid solution depends on the repulsive interaction between neighboring oxygen ions.