Mechanical Response of Hierarchical Ysz Membranes with Multi-Scale Voids and Anisometric Macro-Void

Mechanically strong but highly porous structured ceramics are desirable for a range of applications like water purification and energy conversion. Yttria-stabilized zirconia membranes, possessing a hierarchical arrangement of voids from hundreds of micrometers to nanometers, were prepared by a non-solvent induced phase separation technique. Effects of the multi-scale voids on stress distributions and related mechanical properties were experimentally studied and simulated. The gradually varying diameter of the finger-like voids led to a loading direction dependent fracture strength. Meanwhile, no strength degradation was found when penetration depths of these macro-voids increased from 70% to 80% of the membrane thickness, because the void tails caused no interference to the bending stress. The sponge-like structure surrounding the finger-like voids absorbed strains, and the resultant stress concentration determined the fracture strength