Impedance matching optimization mechanism of SiBCN(Ni) absorbing fibers with Ni as catalyst

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 Ni2Si, β-SiC, Si3N4, and Si2N2O, resulting in the presence of multiple heterogeneous interfaces and excellent polarization loss capability. The Ni2Si 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 (RLmin) 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.