Aligned and porous alumina ceramics prepared by camphene-based freeze-casting route: microstructure and properties

Abstract

This investigation reports a novel room-temperature camphene-based freeze-casting method to prepare aligned and porous alumina ceramics. The ceramic/camphene/dispersant mixed slurries were solidified using a fast room-temperature cooling installation to form excessively overgrown camphene dendrites. The experimental results revealed that camphene-based freeze casting could lead to formation of an aligned and porous structure through room-temperature cooling in a copper die. As the ceramic solid loading increased from 8 to 20 vol.-%, the total porosity of the sintered porous alumina ceramics ranged from 80·5 to 67·5% and the compressive strength increased from 5·8 to 23·5 MPa. This freeze-cast processing is considered potentially useful in fabricating novel porous ceramics with special structure.