Porous alumina/zirconia layered composites with unidirectional pore channels processed using a tertiary-butyl alcohol-based freeze casting

Symmetric three-layer porous alumina/zirconia composites with controlled "designer" pore structure have been prepared by a tertiary-butyl alcohol-based freeze casting and sintering at 1400-1500 degrees C in air. Unidirectional aligned macropore channels were developed over a long range by controlling the solidification direction of tertiary-butyl alcohol solvent; in this case, they were surrounded by more dense structured walls. In layered composite, the bottom layer consisted of small sized pore channels (similar to 11 mu m in diameter) compared with the middle and the top layer, due to the comparatively rapid velocity of the TBA crystal growth during solidification. The compressive strength (63-376 MPa) of the sintered porous layered composite remarkably increased as the porosity decreased (64-32%). (C) 2011 Elsevier B.V. All rights reserved.