Carbon onions growth mechanism

Growth Mechanisms of Carbon Onions Obtained by Electron Irradiation... 

Ozawa et al. proposed another growth mechanisms of carbon onions based on TEM observations of carbon black irradiated by an electron beam [13]. Spiroids are first formed and then carbon onions (Figure 3.3). Qin and lijima also studied the formation of spheroid graphitic particles by irradiating diamond crystals inside a TEM [14]. Since the mechanism of carbon onion formation was not known, several studies were carried out to follow the transformation of diamond nanoparticles into carbon onions directly inside a transmission electron... 

Figure 3.3 Growth mechanism of carbon onion from spiroid proposed by Ozawa et al. Reproduced by permission of American Chemical Society from Ozawa et al. [13], Figure 3, (2002) American Chemical Society...

Thus far, four mechanisms for the formation of concentric shell carbon particles as zero-dimensional carbon allotropes have been proposed. The first mechanism is the formation of a corannulene carbon framework followed by a spiral-shell growth [48], The second mechanism is that the regular concentric arrangements of carbon layers in the onion-like caibon sphere occur tlirough the solidification process of a carbon droplet under ultrafast condensation (49J. The third mechanism is due to a solid—>quasi-liquid—>solid process tliat is, reorganization of soot-containing tubular and polyhedral graphitic particles by... 

---