Effects of various YSZ contents on fracture toughness of macroporous alumina supports

Compared with the supports without YSI powders, the improvements of fracture toughness for macroporous alumina ceramic supports by doping Y₂O₃ stabilized ZrO₂ (YSZ) powders were investigated by the dry prassing method. The effect of YSZ content on the apparent porosity, the bending strength and the fracture toughness of the supports heated at 1 400°C, 1 450°C, 1 500°C, 1 550°C and 1 600°C were obtained. The XRD analysis results show that YSZ powders play an important role in the increments of the mechanical properties, especially in the increment of the fracture toughness, that the optimum values exist when the amount of YSZ is 6 wt% in the supports prepared at 1600°C, and the corresponding fracture toughness and bending strength are 2.5 MPa·m1/2 and 137 MPa respectively, and that the phase transformation of t-ZrO₂ into m-ZrO₂ is the main cause which improves the fracture toughness of Al2O₃/YSZ supports.