SiC-based Ceramic Materials Incorporating GNPs Array: Preparation and Mechanical Characterization

Silicon carbide ceramics are important engineering materials, but their application is limited by the inherent brittleness. Two-dimensional graphene, with its excellent properties, can be used as a second phase to improve the performance of silicon carbide ceramics. However, due to poor dispersion of graphene in the ceramic matrix, it is a challenge to fully exploit the modifying effect of graphene in composite materials. To address these challenges,SiC-based ceramic materials incorporating graphene nanosheets（GNPs） were synthesized using ceramic organic precursor polycarbosilane and industrial expandable graphite as starting materials. The precursor intercalation technique was employed to fabricate SiC/GNPs ceramic composites with GNPs volume fraction of 1%, 3%, and 5%.The GNPs were uniformly arranged in an array-like parallel fashion in the SiC ceramic matrix, showing excellent orientation. With the GNPs content increasing, the spacing between GNPs within the array decreased, indicating tunable microstructural topology. The addition of GNPs greatly enhanced the fracture toughness of SiC ceramics.When the GNPs content was 3%, the relative density of the samples reached 98.5%, the bending strength reached 445 MPa, and the fracture toughness（KIC value） peaked at 5.67 MPa·m1/2, surpassing pure SiC ceramics by 40%,which was primarily attributed to crack deflection and bridging induced by the GNPs. However, further increase in GNPs content led to a decrease in fracture toughness to 4.37 MPa·m1/2. These SiC-based ceramic composites with a graphene array have potential application in design and development of novel "structure-function integration"SiC-based ceramic devices.