Microstructural modulation of carbon for enhanced broadband microwave absorption in CNWs/ZrO2 modified SiOC ceramics

Carbon materials exhibit significant potential as electromagnetic (EM) wave absorbers; however, their practical application is restricted by excessively high electrical conductivity. To address this issue, a ZrO 2 /SiOC ceramic incorporating a three-dimensional (3D) carbon nanowires (CNWs) architecture is developed using polymer-derived ceramics (PDCs) technique. In this design, ZrO 2 nanocrystals and dual-morphology CNWs (twisted/straight) are synergistically integrated within the SiOC matrix, with the pyrolysis temperature regulating the evolution of carbon structures from branched clusters to twisted CNWs and eventually to straight CNWs. Experimental results demonstrate that the CNWs/ZrO 2 /SiOC ceramic (designated as the Zr-Si-2 sample) exhibits a minimum reflection loss (RL min ) of −35.1 dB at a loading of 40 wt% and a thickness of 4.35 mm. Moreover, an effective absorption bandwidth (EAB) of 5.2 GHz is achieved at a thickness of 2.50 mm. This excellent EM wave attenuation performance is attributed to several key factors, including the abundant nano-interfaces (encompassing both homogeneous and heterogeneous) formed by twisted and straight CNWs within the matrix, intrinsic defects present in both the SiOC matrix and CNWs, lattice distortion in ZrO 2 , and the 3D CNWs architecture. In addition to proposing a novel fabrication method for high-performance microwave absorbers, this study establishes a valuable scientific foundation for materials research and applications in relevant fields.