Structure analysis of BaCe0.8Y0.2O3-δ in dry and wet atmospheres by high-temperature X-ray diffraction measurement

High temperature X-ray diffraction measurements were performed under dry and wet atmospheres to investigate phase behavior of BaCe0.8Y0.2O3-delta (BCY20). In the temperature range of 30-400 degrees C, BCY20 was identified to be rhombohedral and monoclinic structures in dry and wet atmospheres, respectively. Larger lattice volumes were obtained in a wet atmosphere due to a chemical expansion induced by water incorporation. A gradual change in diffraction peak shape due to a phase transformation from rhombohedral to monoclinic was observed at 300 degrees C when moisture was introduced into the atmosphere. These results indicated clearly the dependence of phase behavior of BCY20 on partial pressure of water vapor in atmosphere. (c) 2013 Elsevier Inc. All rights reserved.