YAO Sen, LIN Hongyu, ZENG Xiaozhou, ZHUANG Yanhong, LI Chenyu, LI Yang
(School of Materials and Architectural Engineering, Guizhou Normal Universtiy, Guiyang 550025, Guizhou, China)

Abstract: Porous alumina ceramics were prepared by molding method with fused alumina micron powder as aggregate, alkaline silica solution as high temperature binder and carboxymethycellulose as molding promoter. The effect of silica solution content and sintered temperature on linear shrinkage, flexural strength, microstructure and porosity of the porous ceramics were investigated. Results indicated that the linear shrinkage and flexural strength increased with silica solution content, while the porosity decreased. When the silica solution content was 5%-15% with the sintered temperature from 1250 ℃-1350 ℃, the porous ceramics had an excellent porosity, and the porosity was about 27.8%-40.1%. When the silica solution surpassed 20%, the superabundant silica crystal derived from the solution degraded the flexural strength and porosity.
Key words: silica solution; porous alumina ceramics; binder; silicon dioxide