Papers by Author: Li Ming Lin

Abstract: A porous alumina with cylindrical pores was fabricated by unidirectional solidification under hydrogen gas flow (0.1 MPa) using alumina feed rods doped with silica, calcia or sodium oxide. The additives in the feed rods strongly affect the formation of porous structure during the solidification. The porosity increases with increasing silica content. The increase of porosity is enhanced by further addition of sodium oxide. The addition of calcia to the feed rod is effective on the homogenization of pore distribution. The porous alumina with 1mol%CaO and 20mol%SiO2 additives showed 50% porosity and homogeneous pores distribution.

Abstract: A new fabrication method of porous ceramics using unidirectional solidification was proposed in this paper and the role of silica additive on the formation of porous alumina structure was discussed. A porous alumina was formed by unidirectional solidification process that was conducted using floating zone melt method in hydrogen atmosphere at normal pressure. The effect of silica additive on the porosity and the pore size of the solidified samples was examined. The porosity of the solidified samples increased with increase of silica contents. On the other hand, the pore size decreased with increase of silica content. The average pore size of 10% and 20% silica added samples were 0.396 mm and 0.184 mm, respectively.