Fabrication of porous Al2TiO5-Al2O3 ceramics using Al2O3 hollow spheres coated with TiO2 sol

Currently, porous Al 2 O 3 ceramics have attracted extensive attention because of their unique properties. However, the low strength of porous Al 2 O 3 ceramics constrains their practical application. Herein, the porous Al 2 TiO 5 –Al 2 O 3 ceramics with higher strength were prepared through the Al 2 O 3 hollow spheres (HSs) coated with TiO 2 sol using co-precipitation method. The present work is to study the effects of Al 2 TiO 5 solution content on the sintering behavior and mechanical properties of porous Al 2 O 3 ceramics. Then, the enhancement mechanism was analyzed by comparison of the bulk density, porous, shrinkage, compressive strength , and the resultant microstructure. With Ti(SO 4 ) 2 solution content as the primary parameter to control the Al 2 TiO 5 content, it was found that when Ti(SO 4 ) 2 solution content was 15 mL, the minimum value of porosity reached 30.4%, while the maximum values of bulk density and shrinkage reached 2.52 g/cm 3 and 9.4%, respectively. Furthermore, the compressive strength of porous Al 2 O 3 ceramics containing 15 mL Ti(SO 4 ) 2 solution reached a maximum of 53.1 MPa, which is attributed to the formation of the liquid phase and the presence of elongated Al 2 TiO 5 grains. This results from the improvement of bonding strength between Al 2 O 3 HSs.