Foldcore sandwich structure formed by BN-coated graphene nanosheets grafted to SiC fibers with enhanced mechanical performance

To improve the strong interface between fibers and ceramic matrix in silicon carbide (SiC) fibers reinforced in ceramic matrix composites (CMCs), tremendous efforts have been devoted to the fabrication of fiber coating. However, the design and preparation of these fiber coatings still remain a considerable challenge. In this study, we report a novel strategy to synthesize foldcore sandwich structure formed by boron nitride (BN)-coated graphene nanosheets (GNS) grafted to SiC fibers and analyze how the presence of GNS/BN composite coatings influences the mechanical performance of the fibers. In the fracture process, GNS-grafted SiC fibers coated with BN provide a specific wrinkled and malleable surface, which can be flattened and then broken in the early fracture stage. As a result, the fracture process is changed, resulting in enhanced mechanical performance. Our strategy could be further extended to the fabrication of other composite coatings on fibers with enhanced mechanical properties.