Preparation and properties of high toughness RBAO macroporous membrane support

Reaction bonding of aluminum oxide (RBAO) is a novel technique for preparing porous alumina. By adapting this manufacturing route, macroporous Al2O3 supports with high fracture toughness are prepared for ceramic membrane. The effects of sintering temperatures and aluminum (Al) content on mechanical properties of macroporous Al2O3 supports are investigated, especially for the improvement of fracture toughness. When the sintering temperatures increase from 1200 °C to 1600 °C, increments of fracture toughness and bending strength are observed. Sintered at 1600 °C, when Al content is 16 wt%, the maximum value of fracture toughness and bending strength of macroporous Al2O3 supports are 2.0 MPa m1/2 and 137 MPa, respectively, which are 2.0 and 2.6 times than that of the supports without adding any additives. By SEM analysis, many fine Al2O3 particles form a network which is beneficial to the improvements of fracture toughness and bending strength. After corroded in nitric acid and sodium hydroxide solutions of 1 mol L−1 at 80 °C for 168 h, respectively, the mass loss percentage is lower than 1 wt%. And the bending strength keeps at the level of ∼40 MPa which is strong enough to apply in industry. Simultaneously, the toughening mechanism of RBAO macroporous support is also discussed.