In-situ polymer-derived SiOCnws-Cf/SiC(rGO) composites: a potential candidate for EMI shielding and thermal management
The rapid evolution of aerospace technology necessitates the development of multi-functional composites that combine light weight, mechanical robustness, thermal protection/insulation, and electromagnetic interference (EMI) shielding. C/SiC porous ceramic composites are promising for thermal protection in hypersonic vehicles. Here, we report a facile strategy to fabricate Cf/SiC composite polymer-derived ceramics (PDCs) via re-pyrolysis of high-energy ball-milled polycarbosilane-vinyltriethoxysilane-graphene oxide (PVG) with Cf/SiC(rGO)p blend interleaves. In-situ generated honeycomb-like cellular structures and non-directional channels reduce density and increase porosity. High-quality SiO2 joints, formed from Si-dangling bonds, strengthen interfacial bonding via a brazing effect, while in-situ SiOC nanowires (SiOCnws) create a hierarchically enhanced network, improving fracture toughness and crack resistance. Multi-scale interfacial/dipole polarization enhances EMI shielding. The optimized Cf(0.2)/SiC(rGO) composite exhibits low density (1.49 g cm−3), high fracture toughness (6.32 MPa m1/2), hardness (7.18 GPa), compressive strength (72.67 MPa), and EMI shielding effectiveness of 58.31 dB. It maintains structural stability under butane blowtorch ablation at ~1300 °C for 3600 s. Porous variants show thermal conductivity of 0.211 W m−1 K−1 with 69.74% porosity. These multi-functional composites are promising for thermal protection systems in aerospace applications.