Reasons analysis
In order to compare the difference of surface morphology of
nanometer and micrometer aluminum powders, Scanning Electron
Microscopy (SEM) was used to scan 100 nm and 75 lm aluminum
powder as shown in Fig. 9.
From Fig. 9 we can clearly see: the particles of 100 nm aluminum
powders are spherical and their shapes are like heaped beans.
Among them there are also some larger particles, which may be the
oxidation products. The morphologies of 75 lm aluminum powders
are completely different from those of 100 nm aluminum
powders, and their shapes are squamous. There are some agglomerations
formed among aluminum powder, and it is difficult to
determine their average particle sizes.
The activity of nano-aluminum powder is much higher than the
normal one [24]. Firstly, nano-aluminum powders are produced in
vacuum or inert gas media, so contaminations from the environment
is not easy. Meanwhile, metal aluminum is vaporized into