Ionic conductivity and mechanical properties of Y2O3-doped CeO2 ceramics synthesis by microwave-induced combustion

Abstract We developed a new method, i.e. microwave-induced combustion synthesis to produce highly sinterable Y 2 O 3 -doped CeO 2 nanopowders. The process took only 15 min to yield Y 2 O 3 -doped CeO 2 powders. We also investigated the conductivity of Y 2 O 3 -doped CeO 2 ceramics. It was found Y 2 O 3 concentration to have a large effect on the morphology, activation energy, ionic conductivity, and mechanical properties of Y 2 O 3 -doped CeO 2 ceramics. The results revealed that the bulk densities of Y 2 O 3 -doped CeO 2 ceramics sintered at 1420 °C for 5 h were all higher than 92% of the theoretical densities, and the maximum ionic conductivity, σ 800 °C = 0.023 S/cm at 800 °C, the minimum activation energy, E a = 0.954 eV determined in the temperature of 300–800 °C and the maximum fracture toughness, K IC = 1.825 ± 0.188 MPa m 1/2 were found for 9 mol.% Y 2 O 3 -doped CeO 2 specimen. The grain size of CeO 2 decreases with increasing Y 2 O 3 concentration. The fracture toughness was found to increase at increased Y 2 O 3 concentration, because of the decrease of CeO 2 grain size.