Silicon carbide nanowires are valuable for electronic and optical applications, due to their high mechanical and electrical properties. Previous studies demonstrated that nanowires can be produced easily, by mixing a silicon-based compound (Si or SiO2) with a carbon source (C or SiC), in an inert gas atmosphere (Ar or He). The result of this reaction is an elevated number of core–shell SiC-SiOx nanowires. The mechanism of formation of these wires should be inquired, in order to control the process. In this work, SiO2 and SiC are chosen as raw materials for SiO(g) and CO(g) production. These two gases react at SiC surfaces and generate the core–shell nanowires. SEM, TEM and XPS analyses confirm the composition and the microstructure of the product. A three-step mechanism of formation is proposed. The formation of nanowires is compared with thermodynamics of reactions occurring in the Si-C-O system. It is found that nanowires develop in wide temperature and SiO partial pressure ranges (T: 924 °C to 1750 °C, pSiO = 0.50 to 0.74). Higher He flows will shift the reaction to lower temperatures and pSiO.

中文翻译：

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SiC-SiOx 核壳纳米线的表征、热力学和形成机制

碳化硅纳米线由于其高机械和电性能而对电子和光学应用很有价值。先前的研究表明，通过在惰性气体气氛（Ar 或 He）中将硅基化合物（Si 或 SiO2）与碳源（C 或 SiC）混合，可以轻松生产纳米线。该反应的结果是核壳 SiC-SiOx 纳米线数量增加。应探究这些线的形成机制，以控制该过程。在这项工作中，选择 SiO2 和 SiC 作为 SiO(g) 和 CO(g) 生产的原材料。这两种气体在 SiC 表面反应并生成核壳纳米线。SEM、TEM 和 XPS 分析证实了产品的成分和微观结构。提出了一个三步形成机制。纳米线的形成与发生在 Si-CO 系统中的反应的热力学进行了比较。发现纳米线在较宽的温度和 SiO 分压范围内发展（T：924°C 至 1750°C，pSiO = 0.50 至 0.74）。较高的 He 流量会将反应转移到较低的温度和 pSiO。