SiBCN ceramic materials are widely studied in electromagnetic wave (EMW) absorption. However, their practical application is limited due to the problem of poor impedance matching. In this study, SiBCN (Ni) fibers were successfully prepared by doping magnetic metal Ni, and the absorption properties of the samples were systematically investigated at different high-temperature treatments (1200 °C–1500 °C). The results showed that the doping of Ni contributed to the formation of carbon nanotubes (CNTs), which could enhance the improvement of conductive loss performance. Additionally, the catalytic effect of Ni promoted the formation of various crystals, including Ni 2 Si, β-SiC, Si 3 N 4 , and Si 2 N 2 O, resulting in the presence of multiple heterogeneous interfaces and excellent polarization loss capability. The Ni 2 Si particles acted as magnetic loss units, thereby enhancing the impedance matching of the fibers. Consequently, the SiBCN (Ni) sample prepared at 1300 °C exhibited a minimum reflection loss (RL min ) of −21.38 dB and an effective absorption band (EAB) of 3.68 GHz. In addition, SiBCN (Ni) fibers coating proved effective in reducing Radar Cross Section (RCS) signals. Therefore, these findings suggest that SiBCN (Ni) fibers have the potential to serve as EMW absorbers in military radar and satellite communication.
In this work, SiBCN fibers with excellent electromagnetic wave (EMW) absorption performance were fabricated using electrospinning technology, followed by curing, pyrolysis, and heat treatment. Microstructure evolution and EMW absorption performance of SiBCN fibers after heat treatment at 1200–1600 °C were investigated. After heat treatment at 1200 °C, the conductive turbostratic C was precipitated from amorphous SiBCN fibers, resulting in minimum reflection loss (RL min ) reaching −63 dB and efficient absorption bandwidth (EAB) reaching 5.2 GHz. While turbostratic C and nano-SiC grains were simultaneously precipitated from SiBCN fibers heat treated at 1400 °C, and the RL min reached −67 dB. The excellent EMW absorption performance of SiBCN fibers was mainly attributed to the synergistic effect of conductive loss, dipole polarization, and interfacial polarization. This work can guide the fabrication of high-performance EMW-absorbing ceramic fibers.
The increasingly complex electromagnetic environment and escalating stealth technology requirements pose unprecedented challenges to multifunctional electromagnetic wave (EMW) absorbing materials. While significant progress has been made, existing SiBCN material systems still struggle to simultaneously achieve broadband absorption and strong attenuation. In response to this demand, we propose a Fe-Co-Ni ternary co-doping strategy from the perspective of multiple doping and magnetic medium coupling. By precisely controlling the content of magnetic elements, the synergistic effect between magnetic loss and dielectric loss is realized. The experimental results show that the minimum reflection loss (RL min ) of the optimized SiBCN/Fe-Co-Ni fibers reach -53.19 dB, and a broadband absorption of 5.36 GHz is achieved at a thickness of 1.98 mm. More importantly, the material maintains excellent stealth performance across a wide range of incident angles. Capitalizing on these outstanding properties, we have successfully designed a low radar cross-section (RCS) stealth antenna. The antenna exhibits a 27.5 dBsm RCS reduction at 9.24 GHz. This work not only clarifies the synergistic mechanism of multiple magnetic doping to regulate electromagnetic parameters, but also provides new ideas for the development of new generation of smart stealth materials and devices.
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