Page 187 - Materials Chemistry, Second Edition

174 3 Metals

Figure 3.12. Illustration of an atomizer for the production of metallic powders. The molten metal/alloy is
sprayed into a cooling tower under the flow of an atomizing gas. The particulates are allowed to cool as
they descend downward, and are collected in a hopper at the bottom of the tower. Reproduced
with permission from Crucible Materials Corporation (http://www.cruciblecompaction.com/process/
atomization.cfm).

former consists of gaseous ground-state and excited-state metallic atoms, the latter
contains electrons and metallic ions that are much more reactive.
By varying parameters such as jet design, pressure and volume of the atomizing
fluid, and density of the liquid metal stream, it is possible to control the overall
particle size and shape. In principle, atomization is applicable to all metals that can
be melted, and is commercially used for the production of iron, steels, alloy steels,
copper, brass, bronze, and other low-melting-point metals such as aluminum, tin,
lead, zinc, and cadmium.
Atomization is particularly useful for the production of homogeneous powdered
alloys, since the constituent metals are intimately mixed in the molten state. Further,