The effects of Ca doping on the O ion diffusion and phase transition in oxide ion conductors La2Mo2O9 was investigated by low frequency internal friction measurement and X-ray diffraction. It was found that the 2 relaxation sub-peaks at lower temperature, which were associated with the O ion diffusion, and the phase transition peak at higher temperature were affected seriously by Ca doping. With the increase of Ca doping content, the peak height of the relaxation peak decreased, but the activation energy increased at first and then decreased. From the influence of Ca doping on the peak height and activation energy of the relaxation peaks, it was deduced that Ca doping could make the O ion diffusion easier in some doping content. As for the phase transition around 833K, substituting La3+ cation in some degree with divalent Ca2+ could suppress it and maintain the high temperature phase to lower temperatures, which help to improve the O ions conducting property.

Effects of Ca Doping on the Oxygen Ion Diffusion and Phase Transition in Oxide Ion Conductor La2Mo2O9. X.P.Wang, Q.F.Fang: Solid State Ionics, 2002, 146[1-2], 185-93