Effect of Al2O3-CeO2 molar ratio on mechanical properties of SiC ceramics

In the present work, SiC ceramic samples with Al 2 O 3 and CeO 2 sintering additives were prepared by spark plasma sintering (SPS). The effects of Al 2 O 3 to CeO 2 molar ratio from 6.25:3.75 to 5:5, 4:6 and 3:7 on sintering behavior, microstructure, Vickers hardness , and fracture toughness of the SiC ceramic samples were investigated and compared. The results showed that, the relative density of SiC ceramic samples increased from 97.8% to 99.2%, and the Vickers hardness increased from 19.72 ± 0.41 GPa to 21.18 ± 0.92 GPa as the CeO 2 molar ratio increased. The increase in CeO 2 molar ratio effectively improved the densification and hardness of SiC ceramics.