Investigation of the preparation methods and mechanical properties of graphene nanoplatelets/α-SiC ceramic composites

While graphene is widely acknowledged for its potential in enhancing the toughness of ceramic composites, achieving substantial mechanical improvements through simple and scalable processing methods remains a challenge. This study demonstrates that minimal additions of graphene nanoplatelets (GNPs) can significantly enhance the fracture toughness of silicon carbide (SiC) ceramics using pressureless sintering. The investigation focused on examining the influence of GNPs addition on the phase composition, porosity, mechanical properties, and microstructure of these composite ceramic materials. By incorporating only 1–3 wt.% GNPs into an α-SiC matrix, a remarkable 37.86% increase in fracture toughness (5.28 MPa·m1/2) is achieved at the optimal loading of 1 wt.%, surpassing the toughening efficiency typically reported for similar composite systems. Microstructural analysis revealed that the primary toughening mechanisms of GNPs in SiC involve pull-out and crack deflection. This study demonstrates GNPs combined with pressureless sintering can effectively unlock the toughness potential of SiC ceramics, providing a practical and scalable approach for industrial applications.