Electron trapping sites near oxygen vacancies in stabilized zirconia

Defects structures due to oxygen vacancies in stabilized zirconia are analyzed focusing on their electron trapping power under reducing conditions: the electrons released during reduction reactions give rise to electronic centers which immobilize the oxygen vacancies involved in the defects. The effective decrease of the migrating oxygen vacancies caused by this process may affect the ionic conductivity of the material. Thermal stability and dependence on yttria concentration of these defect complexes, investigated by means of electron paramagnetic resonance spectroscopy, are reviewed to determine composition and possible regeneration treatments which minimize the number of these electronic centers.