Influence of process parameters on SAC305 lead-free solder powder produced by centrifugal atomization

摘要

In the present work, a centrifugal atomizer was constructed in order to study the effects of operating parameters: rotating speed, melt feed rate, shape and size of atomizer, and oxygen content in the atomizer chamber, on the characters of SAC305 powder. It was evidenced from the experimental results that the median size of the atomized powders became smaller with increasing rotating speed, decreasing melt feed rate, and the use of larger atomizer. At same operating conditions, a cup shaped atomizer was able to give approx. 11% finer powder compared to that from a flat-disk shaped one. Median particle size appeared to be smaller with decreasing oxygen content in the chamber. SEM micrographs revealed that SAC305 particles atomized under atmospheric condition were found to form various shapes: ligament, teardrop, flake, and irregular. The shape of powder particles tends to be rounder with decreasing oxygen content in the chamber. Fine particles of SAC305 powder ( — 45 μm) containing oxygen less than 100 ppm could be synthesized by purging nitrogen gas into the atomizing chamber. Production yield of the SAC305 powder increased with increasing atomizer's rotating speed, lower melt feed rate, and larger atomizer.