High temperature electromagnetic interference shielding of lightweight and flexible ZrC/SiC nanofiber mats

SiC based materials are ideal candidates for electromagnetic-interference (EMI) shielding application at high temperature. Herein, lightweight and flexible ZrC/SiC hybrid nanofiber mats were successfully fabricated by electrospinning and high temperature pyrolysis with polycarbosilane (PCS) and Zirconium acetylacetone ((Zr(acac)3) as precursors. The adding of Zr(acac)3 makes the PCS solution a lower viscosity and higher conductivity. After pyrolysis, highly conductive ZrC nanoparticles are uniformly distributed in the SiC nanofiber matrix. As a result, the average diameter of ZrC/SiC nanofibers is reduced from 2.6 μm to 330 nm compared with pure SiC fibers. Meanwhile, the specific BET surface area (SBET) of ZrC/SiC nanofiber mat is also improved from 51.5 to 131.1 m2/g due to the reduced diameter and rough surface morphology. Meanwhile, the electrical conductivity of ZrC/SiC nanofiber mat greatly rises from 1.5 × 10−6 to 1.3 × 10−1 S/cm. It is found that 3-layer ZrC/SiC naofiber mats with the total thickness of 1.8 mm achieve the EMI shielding effectiveness (SET) of 18.9 dB. With a low density of 0.06 g/cm3, the specific shielding effectiveness could be as high as 315 dB·cm3·g−1. Moreover, the SET value could be further promoted to 20.1 dB at 600 °C. Such optimized EMI shielding performance indicates that the ZrC/SiC nanofiber mat could be an excellent lightweight and effective EMI shielding material for high temperature application.