The electromagnetic (EM) wave absorption properties of 2-mm-thick silicon carbide nanowire (SiCNW)-epoxy composites were studied in the range of 2-40 GHz using a free-space antenna-based system. The 35 wt % SiCNW composites exhibited dual-frequency EM wave absorptions of -31.7 and -9.8 dB at 8.3 and 27 GHz, respectively. The minimum reflection loss of -32.4 dB was achieved at 31.1 GHz for the composites containing 25 wt % SiCNW. A study of the loss mechanism of EM wave absorption suggests the combination of the electric conductance loss caused by network-like SiCNWs in the resin matrix and the relaxation polarization loss in the interfaces of SiCNWs and the epoxy resin.

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High-purity silicon carbide (SiC) nanowires were synthesized through a catalyst-free arc-discharge process using silicon dioxide powders as a filler in a graphite anode. The characterization of the as-synthesized SiC nanowires showed that the diameter of the single-crystalline SiC nanowires was about 3−15 nm and the length was up to several micrometers. To understand the formation mechanism of the SiC nanowires in the absence of a catalyst, we found that oxygen plays a key role in the growth process and suggest that the growth mechanism of SiC nanowires is a catalyst-free vapor−solid (VS) mechanism. Photoluminescence measurements of the SiC nanowires revealed that the material emits blue-green light with a peak wavelength of 472 nm (CIE coordinates:  x = 0.19, y = 0.24).

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Silicon oxide (SiO2) nanowires were synthesized on a 3 cm × 3 cm Si wafer by thermal evaporation of Si@SiO2 core–shell particles under argon atmosphere at 1000 °C for 1 h. The SiO2 nanowires were of diameters ranging from 30 to 100 nm and the lengths were of several micrometres. The growth mechanism of SiO2 nanowires was studied and suggested to be a vapour–solid mechanism. Field-emission (FE) properties of the Pt coated SiO2 nanowires were studied and the result showed that a turn-on electric field of 2.9 V µm−1 was obtained at the vacuum gap of 200 µm. Good FE properties of the Pt coated SiO2 nanowires resulted from the high aspect ratio of the SiO2 nanowires and the excellent work function of platinum.