The flexural strength and densification behavior of Al2O3-doped Ce0.8Y0.2O1.9 electrolyte composites

The Ce0.8Y0.2O1.9/Al2O3 composite powders with 0–10 mol% Al2O3 were prepared by a sol–gel low-temperature combustion process. The influence of Al2O3 content on sintering, grain growth behavior and flexural strength of Ce0.8Y0.2O1.9/Al2O3 composites was investigated. The experimental results show that the relative density and average grain size of the sintered Y2O3-doped CeO2 increases with the increasing Al2O3 content and then decreases when the content is above 0.5 mol%. The relative density of 0.5 mol% Al2O3-doped and undoped Ce0.8Y0.2O1.9 is 99.7% and 90%, respectively, at 1300 °C for 4 h. The introduction of Al2O3 significantly enhances the flexural strength of Ce0.8Y0.2O1.9/Al2O3 composites. The flexural strength is 270 MPa for the specimen containing 10 mol% Al2O3 while the flexural strength is 121 MPa for the Ce0.8Y0.2O1.9 specimen.