Abstract
Zn-22%A1 alloy was atomized by the method of gas atomization, water atomization and centrifugal atomization with various atomizing conditions; to compare the solidified microstructure of obtained powders. Centrifugally atomized powder, gas-atomized powder and water-atomized coarse spherical powder had equiaxed dendrite structure. While the secondary dendrite arm spacings depended on the size of the powder particle, they had no dependence on the kind of atomizing method nor on the conditions, i.e. atomizing temperature and cooling gas. This suggests that the depth of undercooling is more important than the heat loss into atmosphere to determine the solidified structure. Water atomized finer or irregular powder did not have clear structure. This suggests that more rapid solidification occurred in water atomization.
