Preparation of Sn–Pb Spherical Fine Metal Powders by Centrifugal Atomization Based on Mono-Sized Droplets

In order to meet the industrial manufacturing requirements for high-quality powders, a novel hybrid method for the preparation of spherical fine metal powders by centrifugal atomization of mono-sized droplets obtained by the pulsated orifice ejection method was proposed. The Sn–Pb powders with small size, narrow size distribution, high sphericity, and no satellite powders were obtained by this method. The impact of different process parameters on the powder size, particle size distribution, and powder morphology was investigated. The powder size decreased with the increase of the disk diameter, melting temperature, and rotation speed, and the size of the powder particles exhibited a normal bimodal distribution. The width of the liquid flow lines on the rotation disk was expected to be proportional to the size of the powder. The smallest median particle size D50 of the powders obtained was 21.3 μm with the disk diameter of 15 mm, the melting temperature was 573 K, and the rotation speed was 48000 r/min. The difference between the experimental and theoretical values of the particle sizes was analyzed as well. The median diameter D50 is smaller by a considerable margin compared to traditional theoretical values. In addition, the disintegration mode of the liquid film during the atomization process was also discussed. The direct drop formation mode was considered to exist in this novel method that suggests the possibility to implement the microrefinement and improve the controllability of metal powder preparation.