Assembling unidirectionally frozen alumina/camphene bodies for aligned porous alumina ceramics with larger dimensions

This paper proposes a novel way of producing aligned porous alumina ceramics with larger dimensions by assembling unidirectionally frozen alumina/camphene bodies, particularly those containing polystyrene (PS) polymer as the binder. The compressive strength of the samples sintered at 1450 °C for 3 h increased remarkably from 2 ± 0.1 to 16 ± 2 MPa with increasing PS content from 5 to 20 vol.% due to the prevention of cracks generally caused by drying shrinkage. In addition, frozen samples with a PS content of 20 vol.% could be assembled into larger dimensions without difficulty. The height of the assembled sample produced with a lamination number of 5 could be increased to ∼24 mm without a severe decrease in compressive strength (16 ± 3 MPa at a porosity of ∼79 vol.%) due to the maintenance of an aligned porous structure with good interfacial bonding between the laminations.