Effect of low activation rare-earth oxides on sintering of β-SiC

The feasibility of sintering β-SiC at 1850 ℃ with using low-activation rare-earth oxides as sintering additives was studied. Thermodynamic calculation suggested that all five rare-earth oxides (Y2O3, Sc2O3, CeO2, La2O3, and Pr6O11) were suitable sintering additives. Comprehensive microstructure characterization further revealed that Pr6O11 was the most effective sintering additive as it suffered the least influence from the content effect. A mechanism based on liquid phase sintering was proposed based on microstructure observations. The radiation stability of sintered SiC was investigated as well. The intergranular phases (rare-earth oxides and silicates) and SiC grains remained after being irradiated to 17 dpa at 750 ℃.