4.3 Physical and Chemical Vapor Synthesis Processes 49
Figure 4.8 Setup for physical vapor synthesis
of oxide nanoparticles. The metallic precursor
is evaporated, for example, by an electric arc
and transported by an inert carrier gas to the
reaction zone, where the metal particles are
oxidized. Particle growth and agglomeration
are limited in the final quenching step.
Metallic
precursor rod
Energy input
Vapor and
metal clusters
Oxidized
parƟcles
AddiƟon of
reacƟve gas
AddiƟon of
quenching gas
Powder
collector
Carrier gas
gas. As heat source for mass production, an electrical arc, an electron beam, or a
laser have many advantages and are quite often applied. Figure 4.8 displays the
layout of such a system.
A typical industrial product, Fe 2 O 3 , stemming from a process similar to the
one depicted in Figure 4.8 is displayed in Figure 4.9. It shows the characteristic,
Figure 4.9 Fe 2 O 3 powder produced in a
device, similar to the one sketched in Figure
4.8. The broad particle-size distribution, in
this example from 5 to 50 nm, is
characteristic of this type of products.
(Courtesy Nanophase Technologies
Corporation, 1319 Marquette Drive,
Romeoville, IL 60446, USA.
http://www.nanophase.com.)
100 nm