Synthesis of highly porous alumina via powder metallurgy method using TiO2 as sintering additive

Authors: Lê Minh Hải*, Nguyễn Minh Đức, Đặng Quốc Khánh

Abstract

The highly porous alumina was prepared via powder metallurgy route from alumina powder using ammoni bicarbonate (NH4)HCO3 and citric acid as the pore-forming agents and titanium dioxide as the sintering additive. The results shown that a small amount of TiO2 (1%) led to a remarkble enhancement of the bonding between alumina particles due to the formation of new phase Al2TiO5 on the alumina particles surface. Consequently, the densification and the strength of the Al2O3-TiO2 sintered pellets were better than those of Al2O3. The pore sizes determined through SEM observation have an average value of 190 m. The porosity of the sintered samples increases with the concentration of the pore-forming agents and reaches the highest value of 79.3 % corresponding to 80 vol.% ammonia bicarbonate used. The pore size could be controlled by the particle size of the starting pore forming agents, from a few m to a few mm. The thermal resistance of the porous alumina is higher than 1770oC.

Keyword

alumina, titanium dioxide, porous, powder metallurgy
Pages : 57-62

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