Effect of SiC whiskers and graphene nanosheets on the mechanical properties of ZrB2-SiCw-Graphene ceramic composites

Ultrahigh temperature ZrB2-SiCw-Graphene ceramic composites are fabricated by hot pressing ZrB2-SiCw-Graphene oxide powders at 1950 °C and 30 MPa for 1 h. The microstructures of the composites are characterized by Scanning electron microscopy, Raman spectroscopy and X-ray diffraction. The results show that multilayer graphene nanosheets are achieved by thermal reduction of graphene oxide during sintering process. Compared with monolithic ZrB2 materials, flexural strength and fracture toughness are both improved due to the synergistic effect of SiC whisker and graphene nanosheets. The toughening mechanisms mainly are the combination of SiC whisker and graphene nanosheets crack bridging, pulling out.