Three-dimensional CNT lamellae reinforced SiC for enhanced mechanical and electromagnetic shielding properties

Abstract Large-sized carbon nanotube lamella/silicon carbide matrix (CNTL/SiC) composites were fabricated by infiltrating SiC into a lamellar CNT skeleton as a matrix, which avoids the uneven dispersion and high-temperature sintering damage resulting from easily agglomerated CNTs. Due to the highly aligned lamellar structure of the CNTL, the compressive properties of the CNTL/SiC composites were anisotropic and were increased by increasing the number of CVI cycles. The in-plane compressive strengths were higher than the out-of-plane compressive strengths. The flexural strength was as high as 240 ± 5 MPa after 6 CVI cycles. After fracture, the CNTs were pulled-out from matrix, indicating that the CNTs played the main role in bearing load, enhancing the mechanical properties. Since the CNTL/SiC possessed numerous channels, the electromagnetic (EM) waves could be trapped and attenuated by repeated reflection and absorption, yielding outstanding electromagnetic interference (EMI) shielding effectiveness. The total shielding effectiveness (SET) values were significantly determined by the thickness and number of CVI cycles. Consequently, the SET values of the CNTL/SiC reached 33.1–35.7 dB, which means that the EMI shielding effectiveness is excellent.