Uniform carbon nanotube growth on carbon felt preforms: Enhancing mechanical and electromagnetic shielding properties of C/SiC composites

Carbon fiber-reinforced silicon carbide composites (C/SiC) face challenges in achieving concurrent structural and electromagnetic interference (EMI) shielding enhancements while maintaining excellent mechanical properties and thermal stability. This investigation introduces a meticulously designed catalytic chemical vapor deposition (CCVD) approach to enable the in situ growth of carbon nanotubes (CNTs) on carbon fiber preforms. By methodically fine-tuning the process parameters, we achieved precise control over the CNTs’ morphology, density, and spatial distribution. The CNT-modified C/SiC composites demonstrated remarkable multifunctional performance: the bridging effect of CNTs enhanced flexural strength to 122.64 ± 11.65 MPa and fracture toughness to 14.05 ± 2.32 MPa m^1/2. Simultaneously, EMI shielding effectiveness in the X-band reached 38.14 dB, attributed to synergistic effects including three-dimensional conductive network formation, heterogeneous interface effects, and the high specific surface area of CNTs. This work establishes a novel methodology for developing tailor-made ceramic matrix composites with structure-property coordination, showing significant potential for aerospace applications that require integrated electromagnetic protection and mechanical robustness.