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.
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TẠP CHÍ KHOA HỌC VÀ CÔNG NGHỆ Giấy phép số37/GP-BTTTT (15/01/2021) Giấy phép sửa đổi, bổ sung số140/GP-BTTTT (05/3/2021) Đơn vị cấp phép:Bộ Thông tin và Truyền thông Cơ quan chủ quản:Trường Đại học Bách Khoa Hà Nội Phó tổng biên tập phụ trách:GS. Đinh Văn Phong