Preparation and Electromagnetic Wave Absorption Properties of N-Doped SiC Nanowires

Enhancing the conductivity loss of SiC nanowires through doping is beneficial for improving their electromagnetic wave absorption performance. In this work, N-doped SiC nanowires were synthesized using three different methods. The results indicate that a large amount of Si2ON will be generated during the microwave synthesis of SiC nanowires in a nitrogen atmosphere. In addition, the secondary heat-treatment of the as-synthesized SiC nanowires under nitrogen atmosphere will significantly reduce their stacking fault density. When ammonium chloride is introduced as a doped nitrogen source in the reaction raw material, the N-doped SiC nanowires with high-density stacking faults can be synthesized by microwave heating. Therefore, the polarization loss induced by faults and the conductivity loss caused by doping will synergistically enhance the dielectric and EMW absorption properties of SiC nanowires in the range of 2-18 GHz. When the filling ratio of N-doped SiC nanowires is 20 wt.%, the composite shows a minimum reflection loss of -22.2 dB@17.92 GHz, and an effective absorption (RL & LE; -10 dB) bandwidth of 4.24 GHz at the absorber layer thickness of 2.2 mm. Further, the N-doped SiC nanowires also exhibit enhanced high-temperature EMW absorption properties with increasing temperature.

Automated summary

Doping of SiC nanowires improves their electromagnetic wave absorption performance by enhancing the conductivity loss. N-doped SiC nanowires were synthesized using different methods, and the results showed the generation of Si2ON during the microwave synthesis and the reduction of stacking fault density through secondary heat-treatment. N-doped SiC nanowires with high-density stacking faults were successfully synthesized by introducing ammonium chloride as a nitrogen source, resulting in enhanced dielectric and EMW absorption properties in the 2-18 GHz range. The composite with a filling ratio of 20 wt.% exhibited a minimum reflection loss of -22.2 dB@17.92 GHz and an effective absorption bandwidth of 4.24 GHz at a thickness of 2.2 mm. Furthermore, the N-doped SiC nanowires demonstrated enhanced high-temperature EMW absorption properties.