Preparation and properties of nano-SiC strengthening Al2O3 composite ceramics

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 5.1 MPa m1/2 in AS2 composite. The maximum flexural strength was 516 MPa obtained in AS1 composite.