Fracture properties of (CeO₂)_1-x(RO _1.5)_x (R = Y, Gd, and Sm; X = 0.02-0.20) ceramics

The fracture properties of rare earth (yttrium, gadolinium, and samarium) doped ceria ceramics were systematically investigated using the modified small punch method at room temperature in air and at high temperatures in argon gas. The samples prepared by oxalate co-precipitation method showed higher fracture strength than those by solid-state reaction method. In addition, the sintering temperature dependence of gadolinium doped ceria indicated that the highest fracture strength was attained by sintering at 1600 °C. Furthermore, it turned out that the fracture strength was influenced by the dopant concentration rather than the kind of dopant. The relationship between mechanical properties and defect structures are discussed from the dopant concentration, sintering temperature and testing temperature dependence of the fracture strength.