Nonstoichiometry of the fluorite-type oxide solid solutions Ce 1-XYXO2-0.5X-δ (X=0.1, 0.2) was measured as a function of temperature (T=973-1373 K) and oxygen partial pressure (P(O2)=10-2-10-24 atm) by means of thermogravimetry. The result shows that the nonstoichiometry of Ce 1-XYXO2-0.5X-δ (X=0.1, 0.2) is not explained by a simple point defect model, therefore, defect association models are suggested. From the calculation, it is found that (Ce′ CeVÖCe′Ce)x is the major defect association not only in Ce1-XYXO 2-0.5X-δ (X=0.1, 0.2), but also in pure CeO2 for nonstoichiometries less than 0.10. It is also found that the defect association (Ce′CeVÖCe′Ce)x is dominating at lower temperature and smaller X composition.
- Chemical compound
- Defect association