CNT fibers based laminated composites resistant to extreme environments: Synergistic design of electromagnetic shielding performance and high-temperature resistance

Laminated composites were fabricated by introducing PyC, SiC and HfC matrix phases via chemical vapor infiltration (CVI), using flexible carbon nanotube (CNT) fibers with excellent mechanical strength and electromagnetic shielding performance as reinforcements. The field emission properties, tensile strength, thermal conductivity, electromagnetic performance, and high-temperature ablation resistance of the composites with different matrix phases were systematically investigated. The results demonstrated that incorporating the high-melting-point HfC ceramic phase increased the composite's field emission turn-on electric field to 3.8 V·μm⁻¹ while synergistically enhancing load transfer within the CNT fibers network, resulting in a tensile strength of 85.6 MPa. Furthermore, the CNTF/SiC composites achieved a longitudinal thermal conductivity of 18.2 W·m⁻¹·K⁻¹ along with remarkable electromagnetic shielding performance (41-43 dB). Notably, butane torch ablation tests revealed that all three laminated composites retained structural integrity after ablation for 90 s, demonstrating outstanding high-temperature ablation resistance. This study expands the application potential of CNT fibers in high-temperature-resistant and multifunctional composite materials.