Control of graphitization degree and defects of carbon blacks through ball-milling†
In most of the reports, ball-milling of graphitic materials would lead to the decrease of their crystal degree and further amorphization. However, large crystal enhancement of carbon black and graphitized carbon black induced by ball milling were herein observed. The hollow structure of the graphitized carbon black remained without collapse. But from high resolution transmission electron microscopy, the morphology of each nanoparticle is changed from polyhedron to sphere after a certain time of ball-milling. Accordingly, a transformation model was proposed.