Trade-off between microwave absorption and mechanical properties of Core-Shell Zr-Si-C/O fibrous aerogels via phase transformation effect

Ceramic fibrous aerogels are promising lightweight thermal insulators, yet concurrently enhancing mechanical robustness, acoustic attenuation and electromagnetic (EM) wave absorption remains challenging because these functions demand conflicting architectures. Here we introduce a phase-transition-driven multiphase evolution strategy in Si Zr crystals combined with a one-step thermally induced core–shell conversion. This approach enables coordinated regulation of the chemical states, dislocation density and oxygen-vacancy concentration in Zr Si ceramic fibers, and forms a heterogeneous “oxide shell (ZrO 2 /SiO 2 )-carbide core (SiC/ZrC)” within each fiber. The resulting interfacial enrichment and improved impedance matching synergistically strengthen the aerogel and boost EM dissipation. The obtained ZSCO fibrous aerogels deliver a compressive stress up to 255.73 kPa, a minimum reflection loss of −21.87 dB and an average sound absorption coefficient of 0.61. Mechanistic analysis reveals a thermally driven, multimodal regulation pathway for tailoring multifunctional ceramic fibers, offering a scalable route to aerogels for extreme environments.