Carbon fiber is an absorbing material with high strength, acid and alkali resistance, high temperature resistance, flexibility, and processability and plays an important role in the electromagnetic (EM) wave absorption of civil buildings and military equipment. However, its EM wave-absorption performance is poor because of its large complex permittivity and no magnetic loss ability. In this study, dopamine hydrochloride and FeCl₃ were used as precursors, and the Fe₃O₄/N-doped carbon coating was successfully grown in situ on the surface of short carbon fiber (SCF) via dopamine deposition, autopolymerization, FeCl₃ solution immersion, and calcination at high temperature to improve its EM wave-absorption property. The obtained Fe₃O₄/N-doped carbon particles were uniformly attached to the SCF in the form of a thin layer to constitute a unique hierarchical structure. The Fe₃O₄/N-doped carbon coating/SCF displayed an excellent EM wave-absorption performance. An effective bandwidth of 8.64 GHz and lowest reflection loss of −31.38 dB at 3 mm were achieved because of the significant reduction in complex permittivity and improvement in complex permeability, wave impedance, and EM loss ability of the SCF. The Fe₃O₄/N-doped carbon coating is expected to show great potential in EM wave-absorption fields.

Aramid nonwoven (AN), with lightweight and flexible features, is highly attractive as a thermal insulation material to prevent or minimize skin burn damage. However, it has a finite protective effect due to the restriction of the polymer material and the surface hairiness of nonwoven fabrics. This study aimed to introduce different shapes of TiO₂ particles coated with Sn(Sb)O₂ (ATO) so as to promote protective performance by taking advantage of the high refraction of TiO₂@ATO in the visible light (Vis) and near-infrared (NIR) range. It is demonstrated that, compared with AN, the thermal protection effect of the obtained TiO₂@ATO-coated AN (TiO₂@ATO/AN) was significantly improved owing to the excellent radiation and conduction heat-shielding performance of the TiO₂@ATO coating. The micro-morphology, Vis–NIR spectral features, heat-shielding performances, and thermal protective performance (TPP) values of different composite nonwovens were measured to explore their thermal insulation mechanisms and performances. Compared with pristine AN and AN coated with commercial nano-ATO (ATO/AN), the heating rate of TiO₂@ATO/AN heated using an alcohol lamp was much lower. The maximum TPP values of TiO₂@ATO/AN were enhanced to 1457.874 kW·s/m², while the values for AN and ATO/AN were only 432.23 kW·s/m² and 945.054 kW·s/m², respectively. This study proposes an attractive solution for protecting fabrics against heat damage and opens up tremendous possibilities for heat-resistant nonwoven materials applied in the thermal protection field.

The fast progress in wireless communication technology has significantly intensified electromagnetic interference, underscoring the urgent need for developing high-efficiency, low-cost microwave-absorbing materials (MAMs). The current work synthesizes polydopamine microspheres, which can adsorb Co²⁺ and Fe³⁺, followed by the preparation of a nitrogen-doped carbon microsphere/iron cobalt alloy composite microwave absorbing material (NCS/FeCo) via in situ reduction through high-temperature calcination. Additionally, the surface morphology, surface element composition, hysteresis loop, and electromagnetic parameters were investigated, and the reflection loss (RL) was obtained to explore the absorbing mechanism. The results demonstrated that at a 2.5 mm NCS/FeCo thickness, the maximum RL at 13.4 GHz was −55.3 dB, with the corresponding effective absorption bandwidth (EAB) of 11.28 GHz (6.72–18 GHz). Furthermore, the material exhibits excellent microwave-absorbing properties, providing valuable insights to develop efficient microwave-absorbing materials.