Shape modification of graphite particles by rotational impact blending

To modify particle shape of graphite materials, a rotational impact-blending machine was utilized and the effect of operational conditions was investigated in relation to the size and shape of particles. It was also examined on the specific surface area and the crystal structure of particle surface. As a result, a particle shape index, defined as a ratio of short to long axis of an approximated ellipse by Fourier analysis, got large, whereas the particle size became small a bit, as the peripheral velocity of a rotor and the treatment time increased. The specific surface area more or less increased after treatments, and R value of Raman spectroscopy also increased with the treatment time as the lattice defects grow on the particle surface by surface milling or impact. Then, it temporarily decreased due to the generation of new surfaces with a few defects by volumetric grinding. Finally, two regression analyses were carried out on the relationship between the operational conditions and the particle properties like the diameter and the shape index so as to get proper particles. (c) 2005 Elsevier Ltd. All rights reserved.