Preparation of Graphene Nanoplatelets Reinforced SiC Composites by Oscillatory Pressure Sintering

Preparation of SiC-based composites with higher relative density and mechanical properties remains challenging. Herein, we report the fabrication of a category of high performance SiC-based composites using oscillatory pressure assisted sintering (OPS) and 0.5 wt% graphene nanoplatelets (GNPs) as reinforced agents. As the sintering temperature changed from 1860 to 1950 degrees C, the relative density and mean grain size of the composites increased from 98.79% to 99.95% and 1.02 mu m to 1.98 mu m, respectively. The SiC-GNPs composites fabricated by OPS possessed much better mechanical properties in comparison with some published data obtained by other sintering methods. The optimal OPS-prepared temperature of the composites was 1920 degrees C; correspondingly, the relative density, flexural strength, hardness and fracture toughness were 99.72%, 488 MPa, 28.94 GPa and 6.73 MPam1/2, respectively. The crucial toughening mechanisms of crack deflection, crack branching, crack bridging and GNPs bridging were also confirmed.