High-Performance Multifunctional Carbon–Silicon Carbide Composites with Strengthened Reduced Graphene Oxide

Materials with low density, exceptional thermal and corrosion resistance, and ultrahigh mechanical and electromagnetic interference (EMI) shielding performance are urgently demanded for aerospace and military industries. Efficient design of materials' components and microstructures is crucial yet remains highly challenging for achieving the above requirements. Herein, a strengthened reduced graphene oxide (SrGO)-reinforced multi-interfacial carbon–silicon carbide (C-SiC)n matrix (SrGO/(C-SiC)n) composite is reported, which is fabricated by depositing a carbon-strengthening layer into rGO foam followed by alternate filling of pyrocarbon (PyC) and silicon carbide (SiC) via a precursor infiltration pyrolysis (PIP) method. By increasing the number of alternate PIP sequences (n = 1, 3 and 12), the mechanical, electrical, and EMI shielding properties of SrGO/(C-SiC)n composites are significantly increased. The optimal composite exhibits excellent conductivity of 8.52 S·cm–1 and powerful average EMI shielding effectiveness (SE) of 70.2 dB over a broad bandwidth of 32 GHz, covering the entire X-, Ku-, K-, and Ka-bands. The excellent EMI SE benefits from the massive conduction loss in highly conductive SrGO skeletons and polarization relaxation of rich heterogeneous PyC/SiC interfaces. Our composite features low density down to 1.60 g·cm–3 and displays robust compressive properties (up to 163.8 MPa in strength), owing to the uniformly distributed heterogeneous interfaces capable of consuming great fracture energy upon loadings. Moreover, ultrahigh thermostructural stability (up to 2100 °C in Ar) and super corrosion resistance (no strength degradation after long-term acid and alkali immersion) are also discovered. These excellent comprehensive properties, along with ease of low-cost and scalable production, could potentially promote the practical applications of the SrGO/(C-SiC)n composite in the near future.