碳化硼纳米线的制备和结构

以碳纳米管为模板，通过加热碳纳米管与硼粉的混合物，获得了笔直的硼碳纳米线.对纳米线的结构和成分进行研究，结果表明纳米线主要为B4C纳米线.在部分B4C纳米线的端部存在Ni颗粒，这些端部具有Ni颗粒的纳米线构成了纳米磁针.讨论了B4C纳米线的生长机制，B4C纳米线的生长主要为硼原子在碳纳米管中扩散并发生化学反应，使得碳纳米管晶格结构发生重组，形成B4C纳米线.反应后，硼原子部分取代了碳纳米管中碳原子，修补了碳纳米管中的晶格缺陷，获得了形态笔直的B4C纳米线.

Preparation and Structure of Boron Carbide Nanowires

To obtain boron carbide nanowire, the mixture of carbon nanotubes and boron powder is heated to 1000～1100 ℃ for 30～60 min. The results of transmission electronic microscopy examination show that most of the carbon nanotube in our sample transfer into straight boron carbide nanowire. The structure of the nanowire is studied by the selected area electronic diffraction (SAED) and HRTEM, which shows that most of the nanowire is B4C nanowire. There is a nickel particle at the end of some boron carbide nanowires. The nickel particles come from the catalyst encapsulated in the hollow of the carbon nanotube. The growing mechanism of the boron carbide nanowire is discussed. Carbon nanotube acts as template for the growth of boron carbide nanowire. During the reaction, boron atoms replace some sites of the carbon in the nanotube, resulting in reconstructing the crystal of the nanotube and mending the defects in the carbon nanotube.