Dielectric properties and electromagnetic wave absorbing performance of single-source-precursor-derived carbon-rich NbC-SiC-C nanocomposites

For the first time, the present work reports the dielectric properties and electromagnetic wave (EMW) absorbing performance of polymer-derived carbon-rich NbC-SiC-C nanocomposites. In our previous work, NbC-SiC-C nanocomposites with the ultra-high temperature ceramic phase NbC as the main phase were synthesized with the allylhydridopolycarbosilane (AHPCS) and niobium pentachloride (NbCl5) as starting materials. On this basis, divinyl benzene was chosen as carbon-rich source and introduced into the AHPCS and NbCl5 to form a single-source-precursor. Finally, carbon-rich NbC-SiC-C nanocomposites were successfully synthesized by polymer-derived ceramic approach. Compared with ceramic samples without Nb and with lower carbon content, the carbon-rich NbC-SiC-C nanocomposites show extremely enhanced EMW absorbing performance with minimum reflection coefficient of -51.1 dB at 6.88 GHz for the thickness of 2.27 mm. As a consequence, the resultant carbon-rich NbC-SiC-C nanocomposite has to be considered as structure&function integrated material with excellent EMW absorption performance, which can be applied in hostile environment.