EFFECTS OF SEGREGATION ON THE PACKING OF SPHERICAL AND NONSPHERICAL PARTICLES

The packing of particles is important in the processing of the powders and in the ultimate properties of articles processed from the powders . Using an apparatus originally designed for the experimental determin ation of the packing density of powders, segregation effects with sphe rical and nonspherical particles with low aspect ratios were studied. The segregation of the powder samples according to particle sizes occu rred upon vibration of the bed, following the well-known mechanisms of segregation according to size and elutriation segregation due to entr ainment of particles in air. Segregation effects were also demonstrate d with a melamine powder which consisted of nonspherical particles wit h low aspect ratios. Furthermore, additional data are provided for the packing density values of spherical particles with multimodal particl e size distributions, which further support the theory of Ouchiyama an d Tanaka on the packing of spherical particles, when segregation effec ts are not significant.