Toughening macroporous alumina membrane supports with YSZ powders

Macroporous alumina is an important support in membrane fields because of its stabilities to withstand exposure to high temperature, harsh chemical environment and high mechanical strength. However, the essence of brittleness can greatly shorten the life span and restrict the application fields. In this paper, YSZ (ZrO₂ stabilized by 3 mol% Y₂O₃) powders were added into alumina powders to improve the fracture toughness of macroporous Al₂O₃ supports sintered at 1400 °C and 1600 °C. The results show that the fracture toughness and the corresponding bending strength of supports are simultaneously greatly influenced by various YSZ contents. When YSZ content is 6 wt%, the maximum value of the fracture toughness is 3.0 MPa·m^1/2, and the bending strength is up to 90 MPa. By SEM and XRD analysis, the phase transformation of the uniform distribution t-ZrO₂ into m-ZrO₂ is the main cause which improves the fracture toughness of macroporous Al₂O₃ supports. Lowering of the sintering temperature by adding YSZ additives is also discovered here. The fracture toughness of the supports sintered at 1400 °C by adding YSZ powder is higher than that of the supports sintered at 1600 °C without adding any additives.