PARTICLE COATING MECHANISM OF FINE PARTIC LES BY HIGH-SPEED GAS IMPACT - WALL EFFECTS

Recently, there have been various studies on fabrication of composite particles to produce functional materials. Here, high-speed gas impact blending is utilized as a kind of surface-composite method to coat fi ne particles. The coating mechanism is investigated theoretically and experimentally. It is assumed that small particles move between the su rfaces of large particles and the inner wail in collisions. The proces s is described by the number of small particles coated over the large ones after arbitrary impact times. The experimental results with binar y sized particles agreed with simulated ones according to this theory. As a result, it was found that the transfer of small particles betwee n large ones affects the distribution form of the number of small ones over large ones, and that the transfer between large particles and th e inner wall governs the average number of small ones in addition. The refore, it becomes possible to estimate the coating ratio of large par ticles in a certain processing time by this fabrication method.