In situ construction of CNWs/SiC-NWs hybrid network reinforced SiCN with excellent electromagnetic wave absorption properties in X band

Here we report a study regarding the microstructure and dielectric property of carbon nanowires (CNWs)/SiC nanowires (SiC-NWs) network reinforced SiCN ceramics. The combination of hybrid networks with hierarchical porous structure and dual-phase electromagnetic wave (EMW) absorbing materials could provide a very favorable condition for both impedance match and EMW attenuation which are two crucial elements for the achievement of excellent EMW absorption properties. In-situ synthesis was adopted to avoid the aggregation of nanowires thereby enhancing its dispersibility in the matrix. The high specific area and unique microstructure of CNWs and SiC-NWs hybrid network extend the propagation distance of EMW and facilitate the improvement of EMW attenuation in the process of multiple reflections, conductivity loss and polarization loss, thereby optimizing the absorption performance of the composites. CNWs/SiC-NWs/SiCN containing 5.75 wt% CNWs demonstrates excellent EMW absorption performance, achieving an effective absorption bandwidth of 4.2 GHz which covers the whole X band and the minimum reflection coefficient reaches -21.6 dB at a thickness of 2.35 mm. CNWs/SiC-NWs/SiCN composites demonstrate efficient EMW absorbing ability, providing novel ways of designing and reference for the development of EMW absorbing materials. (C) 2020 Elsevier Ltd. All rights reserved.