Creep behavior of porous La0.6Sr0.4Co0.2Fe0.8O3-δ oxygen transport membrane supports

Advanced oxygen transport membrane designs rely upon a thin functional layer supported by a porous substrate material that carries the mechanical loads. The creep deformation behavior needs to be assessed in order to wan-ant a long-term reliable operation at elevated temperatures. The current study reports the creep behavior of porous La0.6Sr0.4Co0.2Fe0.8O3-delta in air for a temperature range of 750-950 degrees C. Stress exponents and activation energies are derived from the deformation data. A comparison with the creep rates of dense material revealed a progressively increasing creep rate with increasing temperature that might be related to surface diffusional effects. Additional tests at room temperature revealed non-linear stress-strain curves and an apparent ferroelastic creep due to domain switching in the rhombohedral phase that is stable at lower temperature. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.