Freeze gelcasting of aqueous alumina suspensions for porous ceramics

A novel route combining the conventional freeze casting and gel casting was proposed for the fabrication of aligned pore structures. In comparison with the conventional freeze casting, the utilization of a water-soluble Hydantoin epoxy resin in the freeze casting promoted the gelation process and led to a higher compressive strength of the green body. After sintering, the freeze gelcast samples exhibited a twice higher compressive strength and 15.6% higher porosity at the same time than those of conventional freeze cast sample. The improvements were attributed to the combination of gelation of Hydantoin epoxy resin and the aligned ice growth, which led to the coexistence of aligned cylindrical and lamellar pore structures.