Mechanical Properties of Sic/Graphene Nano-Platelets Composites Prepared by Sps

Silicon carbide (SiC)/graphene nanoplatelets (GNPs) ceramic composites with additions of 0,1,2,4,6,8 wt.% GNPs were fabricated by spark plasma sintering (SPS). Effects of GNPs addition on densification, microstructure and mechanical properties of the SiC/GNPs composites were investigated. As GNPs content increased, relative density of the composites decreased slightly from 99.0% for monolithic SiC to 98.3% at 8 wt.% GPNs. Uniform distribution of GNPs in the microstructure was exhibited. A small portion of SiC grains was assumedly wrapped by thin-layered GNPs, which could explain microstructural refinement of the composites with CNPs additions. Vickers hardness was increased by 7% (25.4 GPa) in the 1 wt.% GNPs composition relative to monolithic SiC (23.5 GPa) while fracture toughness of the SiC/GNPs composites showed a minimum at 1, 2 wt.% GNPs additions. The mechanical property changes indicated different states of GNPs existence in the SiC/GNPs composites, among which thin-layered GNPs wrapping SiC grains could benefit Vickers hardness relative to agglomeration of GNPs.