Ultralong SiC Nanowires for Electromagnetic Wave Absorption

Ultralong cylindrical and chain-beaded SiC nw with strong wave-absorbing capabilities were successfully synthesized by carbothermal reduction, employing coconut active charcoal as a carbon source, silicon powders as a silicon source, and graphite flake as a growth matrix. The sintering temperature and holding duration considerably influenced the composition, microstructure, morphology, dielectric properties, and absorption traits of SiC nw . Elevated sintering temperature facilitated the transformation from cylindrical to chain-beaded SiC nw . Extending the holding duration from 2 h to 6 h promoted SiC nw growth in both longitudinal and transverse directions. At 1200 °C for 2 h, the cylindrical SiC nw exhibited superior absorption properties, featuring an RL of −65.40 dB at 4.5 mm and 5.32 GHz, along with an EAB of 1.66 GHz spanning 4.64–6.30 GHz. When sintered at 1200 °C for 6 h, the cylindrical SiC nw demonstrated an RL of −57.70 dB at 2.00 mm and 14.86 GHz, along with an EAB of 5.50 GHz between 12.50 and 18.00 GHz. At 1400 °C for 6 h, the chain-beaded SiC nw exhibited an RL of −47.00 dB at 3.50 mm and 5.96 GHz and an EAB of 1.56 GHz across 5.30–6.86 GHz. These insights accentuate the considerable possibilities of SiC nw in electromagnetic wave absorption applications.