Keywords: 
• 多壁碳纳米管 /
• γ射线辐照 /
• 结构转变

Abstract: Purified muhiwalled carbon nanotubes (MWCNTs) were irradiated by ~(60) Co γ-ray with different doses. The structural change of the MWCNTs was revealed by high-resolution transmission electron microscopy and Raman spectroscopy. It was found that under γ-ray irradiation some amorphous structure homogeneously covers the inner tube walls with graphite structure in irradiated MWCNTs. Moreover, the amorphous structure continuously proceeds and the graphite structure is reduced during the γ-ray irradiation till the irradiated MWCNTs become amorphous nanowires with a hollow structure. Based on the interaction between photons and carbon nanotubes, the structural transformation process and the corresponding mechanisms are discussed. In MWCNTs, the collision of a photon with a carbon atom will resuh in displacement of the atom, i.e. formation of a vacancy (single-or multi-vacancy) and a number of primary knock-on atoms which, if their energy is high, leave the tube or displace other atoms in the MWCNTs. If their energy is low, they can be adsorbed onto the tube wails. These adsorbed atoms play the role of interstitials. All the displaced atoms can be sputtered from the MWSNTs. The carbon atoms sputtered from the MWCNTs can further create some damage in a nearby MWCNTs or be absorbed onto its surface. Along with the simple defects, a number of mare complex defects can be formed. The behavior of complex irradiation-induced defects is governed in part by annealing and diffusion of original defects-vacancies and interstltials. The γ-ray irradiation induced structural transformation of MWCNTs was a unique graphite to amorphous structural transition from the outer walls to the inner wails of the irradiated MWCNTs due to the removal of carbon atoms by knock-on displacements.