Development of Particulate Unit Operations and Morphology Property Relations of Particulate Products

Some particulate unit operations (apparatus engineering) are developed to control the particle morphology. The innovative aspect of this operation is the correspondence between the necessary material properties and their apparatus optimization. Spherical powders of aluminum oxynitride and aluminum nitride are directly prepared by flame synthesis (in spite of the fact that oxygen serves as an indispensable reactant). Non-oxide powders are commonly non-spherical with a size below the submicrometer scale. The major limiting factors in their synthesis are free energy, reaction temperature, and reaction rate. The innovative aspect of this flame synthesis technology assisted by DC arc plasma concerns the reducing gas composition beyond 1500 K. A chemical equilibrium calculation indicates that the plasma heating compensates the lack of reaction temperature under a low oxygen condition. This burner realizes a high-speed reaction with the help of reactive species in the arcs. We also report the multilayer-coated cosmetic powders with regard to material application, and the powder bed shear force evaluation equipment with regard to apparatus optimization.Copyright © 2007 by ASME