Powders of Ti x(Sm0.2Ce0.8)1-xO 2-delta, 0 < x < 0.5, were synthesized by the polymeric precursor method. The treatment temperature ranged between 400 and 1000 ºC. The characterization was carried out by X-ray diffraction and the structural refinement study by the Rietveld method. The titanium addition tends to increase the lattice deformation of the crystalline structure, which is not eliminated until the treatment at 700 ºC. Under these conditions, the samples are single phase, cerianite. In the samples treated at 1000 ºC the lattice deformation was suppressed segregating titanium as samarium titanate and rutile, depending on x. The solubility of titanium is limited to x < 0.05. When titanium contents exceed x = 0.05, only samarium titanate precipitates as secondary phase up to x = 0.20. For higher titanium contents (x > 0.20) the rutile phase precipitates. At the same time the samarium titanate content decreases and samarium migrates into the cerianite phase. These phenomena can be proved by the increase in lattice parameters.
X-ray diffraction; Rietveld method
