Production of highly aligned porous alumina ceramics by extruding frozen alumina/camphene body

We herein propose a new technique for producing highly aligned porous ceramics by extruding a frozen ceramic/camphene body. To accomplish this, an alumina/camphene slurry with an initial alumina content of 10. vol% was first frozen unidirectionally in a 20. mm × 20. mm mold and extruded through a reduction die with a cross-section of 5. mm × 5. mm at room-temperature. This simple process enabled the formation of porous alumina ceramics with highly aligned pores as a replica of the camphene dendrites with a preferential orientation parallel to the extrusion direction. The sample showed much higher compressive strength of 280 ± 80. kPa with a porosity of 83. vol% when tested parallel to the direction of pore alignment. In addition, these materials could be used as a valuable framework for the production of ceramic/epoxy composites, particularly with a lamellar structure, which would result in a remarkable increase in mechanical properties.