【摘要】 在 0 .6keVAr+高剂量 (～ 10 2 2 /cm2 )辐照石墨表面 ,借助于高分辨透射电子显微镜 (HRTEM ) ,发现有六方金刚石纳米晶产生 .它们的平均直径介于 1— 5 0nm之间 ,而且晶粒个数约随其直径的增大而直线减少 .有趣的是 ,晶粒具有两种结构模式 :直径小于 10nm的晶粒为单晶结构 ,而直径大于 10nm的为多晶结构 .基于受离子轰击过程特点制约的六方金刚石晶粒成核和成长观点 ,讨论了这种双重结构的形成性质更多还原

【Abstract】 Hexagonal diamond nano\|grains in irradiated surface of graphite produced by ion bombardment at high doses of 0.6?keV Ar\++ have been found,using high\|resolution transmission electron microscopy (HRTEM).The average diameter ( D ) of the grains was varied between ～2 and ～50?nm,and the grain population decreases almost monotonic ally as grain size increases.It is of interest to note that they exhibit a distinctly bimodal structure.For diameters less than 10?nm,the microstructure of grains are single crystals,but the polycrystal structure of nano\|grains with larger diameter (>10?nm) can be also observed.The characteristics of this bimodal structure are on the basis of hexagonal diamond nano\|grain nucleation and growth mechanisms,which are restricted by the characteristics of ion bombardment processes.更多还原