Electrical conductivity of the ZrO2-Ln2O3 (Ln = lanthanides) system

The electrical conductivity of the system ZrO2-Ln(2)O(3) (Ln = lanthanides) has been measured as a function of dopant concentration in a temperature range 350-1000 degrees C. The Arrhenius plots of the conductivity showed a distinct curvature near 600-700 degrees C. The migration enthalpy of oxide ions and the association enthalpy of oxide ion vacancies with the dopant lanthanide ions were estimated from the difference of the activation energy for the conduction in a higher temperature and low temperature range. The electrical conductivity of the systems ZrO2-Ln(2)O(3) depended on the composition and the dopant ion radius. The conductivity decreased with increasing the dopant ion radius, and the composition having the maximum conductivity decreased with increasing the dopant ionic radius. The highest conductivity of 0.3 S/cm at 1000 degrees C was observed in ZrO2 with 11 mol.% Sc2O3. The migration enthalpy in the ZrO2-Ln(2)O(3) systems increased and the association enthalpy decreased with increasing the dopant ion radius. (C) 1999 Elsevier Science BN. All rights reserved.