X-ray study of cerium oxide doped with gadolinium oxide fired at low temperatures

Cerium oxide with different amount of GdO1.5 was prepared by co-precipitation method and fired at temperatures from 600 to 1300 deg. C. The samples were characterized by using X-ray diffraction. The result indicated that in the concentration range of 0-30 mol.% GdO1.5, the samples were in fluorite structure and followed Vegard's law. In the concentration range of 40-50 mol.% GdO1.5, the samples showed the existence of the peaks which did not correspond to fluorite structure and the lattice parameter was independent of gadolinium content. The lattice parameters did not change with extension of annealing time at 600-800 deg. C