Preparation and properties of nano-SiC strengthening Al2O3 composite ceramics

▶ PCS was used to prepare Al2O3/SiC nano-composites. ▶ Nano-composite showed high strength compared with monolithic Al2O3. ▶ Strengthening mechanism included refined structure and residual stress. The processing and mechanical behaviors of Al2O3-xwt.%SiC (x=1, 2, 5, ASx) nano-composites prepared by the in situ synthesis of SiC from polycarbosilane (PCS) were investigated. The composites were densified by hot pressing. The microstructure and mechanical properties of the sintered composites were analyzed. The results showed that a fully dense structure was obtained when a few nano-SiC were doped and that the fracture toughness and strength were highly improved compared with those of monolithic Al2O3. The fracture toughness reached 5.1MPa m1/2 in AS2 composite. The maximum flexural strength was 516MPa obtained in AS1 composite.