Effect of ytterbium doping on the microstructure and plastic deformation of BaCeO3 perovskite oxide

Abstract

Trivalent cation-doped barium cerate perovskites are attractive materials for clean-energy applications, in particular solid oxide fuel cells, due to their singular proton conductivity in wet environments. Furthermore, these devices operate at high temperatures, where creep and other deformation processes determine the lifetime and overall performance. In this work, the structural and microstructural characteristics of undoped and ytterbium-doped (1 to 10at.%) BaCeO3 polycrystals produced by solid state reaction have been investigated. A single orthorhombic perovskite phase was found after sintering in air at 1500°C for 10h. The microstructure shows a complex evolution with doping: the average grain size firstly decreases with increasing Yb content up to 5at.%, and then increases with further Yb additions. The high-temperature mechanical properties have been studied in compression between 1100 and 1250°C in air at constant initial strain rate. The creep strength increases with increasing Yb content. Extended steady states of deformation were attained at lower strain rates and higher temperatures when increasing doping amount.