Mechanical properties of Al2O3–SiC–C composites using polycarbosilane as SiC precursor

Al2O3–SiC–C composites with varying amounts of SiC were prepared by hot pressing method where polycarbosilane (PCS) adopted as the precursor of SiC. The sintering quality, structure-phase state and mechanical properties of composites were measured and compared with Al2O3 monolithic. It was found that the flexural strength increased from 280 MPa for Al2O3 monolithic to the highest of 520 MPa for a 10 wt.% SiC added Al2O3–SiC–C composite, and the fracture toughness was improved from 3.2 to 5.9 MPa m1/2 at the same time. The reinforcement effects were discussed on considering the addition of SiC phase and free carbon in an Al2O3 composite matrix.