Expansion Behavior of Ce[sub 1−y]Gd[sub y]O[sub 2.0−0.5y−δ] under Various Oxygen Partial Pressures Evaluated by HTXRD

Lattice constants and thermal expansion of in the temperature range 25-1000°C were estimated with high-temperature X-ray diffraction (HTXRD) while oxygen partial pressure varied in to Pa. Under oxygen partial pressures higher than 1 Pa, linear thermal expansion was observed, and the expansion coefficient increased with Gd content. In atmospheres with oxygen partial pressures lower than Pa, anomalous expansion due to reduction, which generates oxide-ion vacancies, was observed at temperatures higher than 600°C. By using the result of oxygen nonstoichiometry, lattice expansion behaviors with δ were analyzed. It was revealed that there exists two regions with different expansion behavior against δ in and whereas only a single expansion behavior against δ was observed in showing correspondence with results of oxygen nonstoichiometry. © 2003 The Electrochemical Society. All rights reserved.