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Titanium carbide (TiC) nanowires are synthesized by carbothermal reduction reaction at 1473–1673 K in argon atmosphere. The structure and morphology of TiC nanowires are characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The chemical reaction thermodynamics and the growth mechanism of TiC nanowires are investigated based on the Ti-C-O-Cl system. It involves the formation of gaseous TiClx and CO crucial intermediates, and the further carbon reduction of TiClx to TiC. Based on the thermodynamic analysis, the two-stage growth mechanism of TiC nanowires is discussed. The work could help to analyze the thermochemistry of the carbothermal reduction reaction in the Ti-C-O-Cl system, which is beneficial to optimize the temperature and the input precursors for controlling TiC nanowires growth. [ABSTRACT FROM AUTHOR]

SiC nanowires (NWs) are usually synthesized in a closed vacuum reaction system which limits the yield of SiC NWs. In this work, SiC NWs and carbon nanotubes were synthesized in an open tube furnace at 1550°C with Si powder as silicon sources, ethanol as carbon sources and ferrocene as catalyst. The as‐synthesized products were ultralong β‐SiC NWs with the diameter about 80‐100 nm and the length up to several tens micrometers. The diameter of the carbon nanotubes was about 20‐30 nm. The carbon nanotube yarns about 20 cm in length were obtained at the end of the tube furnace. The growth mechanism of SiC NWs and carbon nanotubes were proposed. Compared with the traditional synthetic techniques in the high vacuum closed system, the novel synthesis method in the open system provided a new approach to the synthesis of SiC NWs. [ABSTRACT FROM AUTHOR]

Flexible papers constructed by one-dimensional nanowires have attracted much attention due to their various applications. Herein, a novel nonwoven fabric with paper-like qualities composed of zinc blende SiC (β-SiC) nanowires was fabricated by a scalable rolling process. The SiC nanowires were synthesized by the carbothermal reduction reaction of the carbon fiber and carbonaceous silica xerogel. The crystal phase, morphology and microscopic structure of the as-prepared SiC nanowires were characterized by field emission scanning electron microscope, X-ray diffraction and high-resolution transmission electron microscopy. The nanowire vapor-solid growth mechanism and preparation process for SiC nanowire nonwoven fabric were also discussed. The freestanding SiC nanowire nonwoven fabric exhibited high flexibility, high mechanical strength, excellent refractory performance and thermal stability. With high flexibility, high mechanical strength, superior nonflammability and thermal stability, the flexible paper-like 3C-SiC nanowire nonwoven fabric materials would be expected to have some potential applications, such as ceramic matrix composites, metal matrix composites, energy storage, catalyst supports, radiation-proof fabric, filtration and separation. [ABSTRACT FROM AUTHOR]

Silicon carbide nanowires (SiC NWs) with different colors (green, blue and white) were synthesized by sol-gel carbothermal reduction method. The chemical composition and morphology of SiC NWs were investigated by multiple characterization methods. It shows that both green and blue products are 3C–SiC NWs and the white product is SiC/SiO 2 cable-structure NWs. The effects of the SiO 2 /C molar ratio of raw materials and the reaction temperature on the fabrication of green, blue and white SiC NWs were investigated. It is found that green SiC NWs tend to generate at high temperature (1600 °C) and low SiO 2 /C molar ratio (1:1). And blue SiC NWs are more likely to form at relatively low temperature (1550 °C) and high SiO 2 /C molar ratio (2:1). In addition, the white SiC/SiO 2 cable-structure NWs were synthesized with high SiO 2 /C molar ratio and low temperature (1500 °C). The two-step growth mechanism was proposed to interpret the growth process. The photoluminescence properties and band gaps of the nanowires were also investigated. It shows that as the size of SiC reduces into nanometer, its band gap enlarges, which leads to the blue-shift of light emission. The discrepancy in emission spectra was assumed to be related to different thickness of their SiO 2 coatings. And the different thickness of SiO 2 coatings results in the multicolor discrepancy of SiC nanowires. • 3C–SiC nanowires with different colors (green, blue and white) were synthesized. • Different thickness of SiO 2 coating results in different colors among SiC nanowires. • The gas partial pressure ratio of SiO/CO would affect the thickness of SiO 2 coating. • Reaction temperature and Si/C/O ratio could affect the supersaturation of SiO and CO. • The white are SiC/SiO 2 nanocables, different from green and blue SiC nanowires. [ABSTRACT FROM AUTHOR]