Fabrication and Property of rGO/SiC Composite

SiC ceramics have excellent mechanical properties, but its toughness is relatively low. To enhance the fracture toughness of SiC ceramics, graphene is introduced as fillers. In this study, the silicon carbide-reduced graphene oxide（SiC/rGO） composites with different contents of rGO were fabricated by hot press sintering（HP）. Near fully-dense SiC/rGO composite was obtained after being hot-pressed under 2050℃, 40 MPa for 1 h. In addition, the influences of graphene reinforcement on the sintering process, microstructure, and mechanical properties（fracture toughness, bending strength, and Vickers hardness） of SiC/rGO composites were discussed. The three-point flexural strength of 4 wt% rGO/SiC composite reached 564 MPa, and the fracture toughness reached 4.02 MPa×m1/2, which were 6% and 54% higher than those of hot-pressed SiC ceramics, respectively. The flexural strength of the three points of 6 wt% rGO/SiC composite was 420 MPa, which was lower than that of hot-pressed SiC ceramics. While its fracture toughness was up to 4.56 MPa×m1/2, which was 75% higher than that of hot-pressed SiC ceramics. The results of crack propagation show that the toughening mechanism can be ascribed to crack deflection, crack bridging and rGO pullout.