Porous alumina/zirconia composites with a controlled "designer" pore structure have been prepared by the tertiary-butyl alcohol (TBA)-based freeze casting technique. The porous materials were characterized in terms of their sintered microstructures, physical and mechanical properties. Unidirectional aligned macropore channels with highly dense structured walls were developed by controlling the solidification direction of the TBA solvent. The sintered porosity and pore size generally decreased with increasing solid loading, this leading to higher compressive strength. The resulting porous materials exhibited an average porosity and compressive strength in the range 63.5-28.8% and 48-341 MPa, respectively, depending on the processing conditions applied. With further addition of zirconia to alumina, the compressive strength was enhanced with a decrease in the porosity, presumably due to the relatively high densification of compacts containing zirconia powder.

Keywords: Alumina/zirconia, Tertiary-butyl alcohol, Solidification, Pore channels, Compressive strength.