Synthesis and electrical properties of Ce_(1-x)Gd_xO_(2-x/2) (x = 0.05-0.3) solid solutions prepared by a citrate-nitrate combustion method

摘要

Ce_(1-x)Gd_xO_(2-x/2) (GDC) powders with different Gd～(3+) contents (x = 0.05-0.3) were prepared by a simple citrate-nitrate combustion method. The influence of the Gd～(3+) doping content on the crystal structure and the electrical properties of GDC were examined. Many analysis techniques such as thermal analysis, X-ray diffraction, nitrogen adsorption analysis, scanning electron microscopy and AC impedance analysis were employed to characterize the GDC powders. The crystallization of the GDC solid solution occurred below 350 °C. The GDC powders calcined at 800 °C showed a typical cubic fluorite structure. The lattice parameter of GDC exhibited a linear relationship with the Gd～(3+) content. As compared with that sintered at other temperatures, the GDC pellet that sintered at 1300 °C had a high relative density of 97%, and showed finer microstructure. The conductivity of GDC was firstly increased and then decreased with the increase of the Gd～(3+) content. The sintered GDC sample with the Gd～(3+)content of 0.25 exhibited the highest conductivity of 1.27 x 10~(-2) S cm~(-1) at 600 °C.