Electromagnetic property of polymer derived SiC–C solid solution formed at ultra-high temperature

Abstract

High-performance electromagnetic interference (EMI) shielding materials in harsh environment are highly required for electronics and aerospace applications. This study reports the EMI shielding property of a polymer derived SiC–C solid solution formed at ultra-high temperature, which has not been reported in the open literature. The average total shielding effectiveness per unit thickness was 29.14 dB/mm, 18.05 dB/mm and 22.08 dB/mm when the polymer derived SiC (PDC-SiC) was annealed at 1700, 1900 and 2000 °C, respectively. High electrical conductivity leads to a high EMI effectiveness of the PDC-SiC annealed at 1700 °C. The electrical conduction loss was decreased while the dielectric loss was increased because of the formation of defects induced by the dissolution of carbon into the SiC lattice. At an annealing temperature of 1500 °C, the PDC-SiC showed microwave absorbing features, with a minimum reflection coefficient (at 3.37 mm) of −53.06 dB at 27.04 GHz. Microstructure characterization revealed that the change and distribution of carbon structure resulted in the electromagnetic property change. The results of this study provided a new method of designing EMI shielding materials by making a carbon solid solution that could change the potential application of the PDC-SiC from microwave absorption to EMI shielding.