Microstructure of Rare-Earth-Doped Ceria Prepared by Oxalate Coprecipitation Method

摘要

Rare-earth-doped ceria powders (Ce_(0.8)R_(0.2)o_(1.9), R =Yb, Y, Gd, Sm, Nd and La),prepared by oxalate coprecipitation, were sintered at 1600 deg C in air. All X-ray diffraction patterns of the samples could be indexed as those of a cubic fluorite structure. The measured lattice parameter and density were well explained by the oxygen vacancy model associated with the substitution of a rare-earth-dopant for cerium. The observation of rare-earth-doped ceria ceramics by high-resolution transmission electron microscopy indicated that no crystalline or amorphous secondary phase formed in the grain interior or at grain boundaries. The rare-earth-dopant elements dissolved uniformly in the bulk and at grain boundaries.