念珠状碳化硅/二氧化硅纳米线的制备及电磁波吸收性能

Synthesis and Electromagnetic Wave Absorption Properties of Beaded Silicon Carbide/Silica Nanowires

通过一种简单、低成本的方法,以竹炭为碳源,在惰性气氛条件下碳热还原二氧化硅,成功制备了念珠状碳化硅(Si C)/二氧化硅(Si O2)纳米线。采用扫描电子显微镜、X射线衍射与X射线光电子能谱对念珠状Si C/Si O2纳米线的微观形貌、物相组成和化学组成进行了表征。结果表明:Si C纳米线表面光滑,直径约为150~200 nm;1~2μm的珠状突起主要成分为Si O2,并均匀分布在Si C纳米线上。室温条件下,在X波段(8.2~12.4 GHz)测试了试样的复介电常数,并以传输线理论计算出样品在不同厚度的反射损耗。结果表明:当厚度为1.80 mm时,试样的有效吸收带宽(RL<–10 d B)为2.32 GHz,最小RL值达到–43.58 d B。

Beaded silicon carbide(Si C)nanowires were synthesized via carbothermic reduction of silica in inert atmosphere with bamboo carbon as a carbon source.The morphology,phase and chemical composition of the beaded Si C/Si O2 nanowires were characterized by scanning electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy.The as-synthesized beaded Si C/Si O2 nanowires with the smooth surface are composed of nanowires with the diameters of150–200 nm and Si O2 beads with the diameters of 1–2μm uniformly distributed on Si C nanowires.The dielectric permittivity of the samples were measured at room temperature at X band(i.e.,8.20–12.40 GHz),and the reflection loss of the samples at different thicknesses was calculated by the transmit line theory.The results show that the effective absorption bandwidth of the composite absorbing materials is 2.32 GHz(RL<–10 d B)with the thickness of 1.80 mm,and the minimum reflection loss of the sample reaches–43.58 d B.