Lotus-type porous alumina was fabricated by unidirectional solidification under hydrogen gas flow (0.1 MPa) and pressurized hydrogen atmosphere using silica and calcia added alumina feed rods. The silica and/or calcia additives in the feed rods strongly affect on the formation of porous structure during the solidification. The porosity increases with increasing silica content. The added calcia in the feed rod is effective on the homogenization of pore distribution. The pores are elongated along the solidification direction. The pores were increased in length when the solidification was performed in pressurized hydrogen atmosphere. A glassy boundary phase which was consisted of silica and calcia components was directly formed in the solidified sample during the solidification. The compressive strength of porous sample with 25.9 percent porosity and non-porous sample prepared in Ar atmosphere were 512 and 1679 MPa, respectively.
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