Polymer-derived SiC-based  ceramic fibrous membranes have attracted increasing attention as lightweight and thermally stable electromagnetic wave absorbers. However, simultaneously achieving strong attenuation capability and good impedance matching remains challenging due to the limited regulation of phase composition and dielectric behavior. In this work, multiphase SiC-based fibrous membranes were prepared by electrospinning combined with polycarbosilane (PCS)-derived ceramic conversion. The phase evolution, fiber morphology, dielectric response, and electromagnetic wave absorption performance were regulated by tuning the PCS content and pyrolysis temperatures. Advanced characterizations confirm the formation of a heterogeneous β-SiC/SiO_xC_y/carbon multiphase structure with good flexibility, which provides abundant polarization centers, moderate conductive pathways, and multiple reflection sites, thereby enabling balanced impedance matching and dielectric loss. Consequently, the sample with a PCS content of 1.4 g pyrolyzed at 1400 °C achieves a minimum reflection loss (RL_min) of −27.12 dB at a matching thickness of 2.2 mm and a maximum effective absorption bandwidth (EAB) of 8.22 GHz at 2.7 mm, covering 9.78-18 GHz. Radar cross-section (RCS) simulation further verifies the electromagnetic scattering suppression capability of the optimized fibrous ceramic coating. Therefore, this study provides a useful strategy for tailoring phase composition and dielectric behavior in polymer-derived SiC-based fibrous membranes for broadband electromagnetic wave absorption.

The preparation of dense high-entropy carbide ceramics (HECCs) is extremely challenging owing to their strong covalent bonding and sluggish diffusion associated with high-entropy effects, which necessitate ultrahigh sintering temperatures that in turn cause severe grain coarsening and excessive energy consumption. In this study, a novel low-temperature consolidation route is developed based on Ti₃AlC₂ reactive sintering. Specifically, the reactive precursor Ti₃AlC₂ decomposes into TiC_x and Al during spark plasma sintering. The in situ formed TiC_x accelerates interdiffusion and solid-solution formation among transition-metal carbides, while the released Al effectively activates particle interfaces. This dual-activation mechanism markedly enhances sintering kinetics, enabling the densification of (TiVNbTaMo)C_x ceramics at 1550 °C. The optimized sample achieved a relative density of 98.5%, a Vickers hardness of 22.94 GPa under a load of 9.8 N, a flexural strength of 1018 MPa, and a fracture toughness of 5.67 MPa·m^1/2, showing superior strength and hardness compared with most reported high-entropy carbides while maintaining an acceptable level of toughness. Furthermore, the interfacial modification results in a stable friction coefficient from room temperature to 900 °C, accompanied by nonadhesive wear behavior at elevated temperatures, making the obtained samples promising for high-temperature structural and wear-resistant applications. Therefore, reactive-Ti₃AlC₂ precursor-assisted sintering provides a new pathway for the design and scalable fabrication of advanced dense high-entropy ceramics under low-temperature conditions.