Chemistry Reference
In-Depth Information
1.0
0.8
0.6
Ar, 200 mL/min
O
2
, 200 mL/min
0.4
0.2
0.0
0
20
40
60
80
Time (min)
FIGURE 8.63
Decomposition of HMX by a pulsed electrical discharge in water for different
gases bubbled through the reactor. The water temperature was kept at 25
◦
C and the concentra-
tion of the added Fe
2
+
ions was 0.3mmol/L. (From Zoh, K.-D. and Stenstrom, M.K.,
Water
Res
., 36, 1331-1341, 2002.)
how water decontamination applications can benefit from a technology based on the
production of reactive species by pulsed electrical discharges in water, results for the
decomposition of the energetic compound HMX in an aqueous solution by pulsed
discharges in water were presented.
8.4 NANO- AND MICROPARTICLES
The accents in fine particle research in plasma technology are gradually shifting from
the traditional view of them as unwelcome process contaminants to new fine powder
materials or to often desired elements that can essentially improve the properties of
plasma-made thin films [422]. Such tailored micro- and nanoparticles in the plasma
phasecanberegardedasbuildingunitsinnanofabricationinvolvingdoping,structural
incorporation, or self-assembly processes.
Production of large amounts of powders in high-pressure thermal plasma jets
(plasma spraying) is state of the art in metal and ceramic industries [423,424]. How-
ever, size distribution and uniformity of produced particles are often rather poor.
A solution is the use of low-pressure plasmas for particle generation and modifica-
tion. A major advantage of low-pressure nonthermal plasmas is the nonequilibrium
chemistry, which provides unique possibilities for fine particle treatment without
damage and thermal overload. Hence, small amounts of particles with a high added
value can be fabricated using these methods. Besides the chemistry, the charge
and size of the particles are crucial parameters for the explanation of the unique
architectures of nano-sized objects such as nanostructured films, nanowires, and
nanotubes.
