中文摘要：

采用能量为80eV的甲烷和氢气混合（1：5）离子束在700℃下辐照多壁碳纳米管得到了石墨纳米晶包覆多壁碳纳米管的复合物。扫描电子显微镜和透射电子显微镜观察表明离子束处理后的多壁碳纳米管被一层粗糙的碳质层包覆。高分辨透射电子显微镜观察显示，该碳层由许多（002）面与碳纳米管管轴角度为45°～90°的石墨纳米晶构成，层内的多壁碳纳米管空腔结构基本不变。甲烷的高温和沉积可认为是石墨纳米晶结构形成的主因，而氢离子束对偏离其方向的石墨晶面的选择性刻蚀是导致最终沉积的石墨纳米晶晶面与纳米管管轴构成大角度分布的原因。

英文摘要：

Nano-graphite （NG） deposits were formed on multi-walled carbon nanotubes （MWCNTs） lying on a single-crystal-silicon plane by irradiating them with an 80 eV ion beam perpendicular to the plane. The ion beam was produced using a methane and hydrogen mixture （ 1 ： 5 ） at 700 ℃. Electron microscopy indicates that there is an angle in the range 45°-90° between the （0002） planes of the formed NG particles and the axis of the MWCNTs. The MWCNTs retained their inner hollow structure. The formation of the NGs can be ascribed to the high temperature decomposition and deposition of methane, and the observation of specific angles （45°-90°） between the （0002） planes of the NGs and the MWCNT axis may be attributed to the selective etching, or removal, by the hydrogen ions of NG nuclei with 0°-45° between their （0002） planes and the MWCNT axis.