Air Permeable Alumina-Based Porous Ceramics with High-Performance Prepared by Novel Gel Casting Route

Abstract

Using carrageenan as cross-linking agent, a gel casting method was used to prepare porous ceramics. Instead of using foaming agent or templates, large size Al2O3 with size of ~45μm were used as skeleton materials, and thus micropores were directly formed in the sintered samples. To tune the pore structure and flexural strength, the micropowders of α-Al2O3 and Kaoling powders as filing materials and rare-earth oxides as sintering additives were introduced. The effect of the content of sintering additives and sintering temperatures on the properties of the through-hole ceramics were investigated. Finally, porous Al2O3 based porous ceramics (with thickness of 8mm) with flexural strength over 160MPa, porosity over 30%, and gas permeability above 30 L/min/cm2 were obtained.

Keywords: Al2O3, Gel casting, Air permeability, Porous ceramic