Preparation of high sphericity monodisperse aluminum microspheres by pulsated orifice ejection method

Abstract

Aluminum microspheres with high sphericity are widely used and urgent demanded in additive manufacturing. However, the current primary atomization method is insufficient in sphericity and particle size distribution. Herein, the monodisperse aluminum microspheres with high sphericity and narrow particle size distribution are successfully prepared by the pulsated orifice ejection method (POEM). The particle size distributions of the prepared aluminum microsphere samples with the average diameter of 325.2 µm are ranged from 315 µm to 332 µm, in which the sphericity of 50% microspheres reached 0.966, and that of 99.59% microspheres reached 0.9. The crucible pressure and interface reaction of aluminum melt with crucible are investigated to explore the influence of technological conditions on aluminum particles. Additionally, the effect of cooling rate on particle size is also studied and the results demonstrate that the sphericity of aluminum microspheres can be improved by decreasing the cooling rate during droplet solidification.