Analysis of Mechanical Loss Spectra in Zirconia Ceramics by Appying the Coupling Model

Mechanical loss spectra (two peaks) observed in ZrO2 doped with Y2O3 (2-10 mol%), are attributed to oxygen vacancy (V)-yttrium (Y) associates (V-Y pairs and V-2Y agglomerates). Both peaks were analysed numerically by applying the coupling model. It has been shown that : i) the activation enthalpy H for both peaks increases with Y2O3 content, ii) the values of coupling parameter n are about 0.6 - 0.7, iii) the activation enthalpy H0 corresponding to the noninteracting system (dilute case) is about 0.4 eV which is considerably smaller than the activation enthalpy for reorientation of isolated dipoles (0.8 - 0.9 eV)