Page 90 - Book Hosokawa Nanoparticle Technology Handbook

FUNDAMENTALS CH. 2 STRUCTURAL CONTROL OF NANOPARTICLES

Figure 2.2.18
Macro and micro changes of solid during its grinding.

Table 2.2.3
Examples of metal nanoparticles synthesized by MC reaction.

Reaction Metal volume ratio (%) Size (nm)
FeCl 3Na Fe 3NaCl 8.1 10–20
3
CuCl 2Na Cu 2NaCl 11.6 20–50
2
CoCl 2Na 1.5NaCl Co 3.5NaCl 6.6 10–20
2
NiCl 2Na 1.5NaCl Ni 3.5NaCl 6.6 5–10
2
it is necessary to depress the thermal elevation, and
for this purpose, it can be made by mixing a dilute
agent in the starting materials, followed by grinding
operation. NaCl plays a significant role as a dilute
agent in the case of the formation of Co nanoparticles
obtained from a mixture of CoCl and Na, as given by
2
the following equation (2.2.18):
CoCl 2Na 1.5NaCl Co 3.5NaCl (2.2.18)

2
The dilute agent plays a role of dispersion to prevent
from aggregation caused by grinding besides the
depression of thermal elevation. As a result, well-
dispersive nanoparticles can be separated by washing
chloride out from the product with solvent. A TEM
photo of the obtained nickel nanoparticles is shown in
Fig. 2.2.19 [4]. From this figure, it is seen that fine
and well-dispersive particles of 5–10 nm in sizes are
recovered.
20 nm
b) Metal oxide nanoparticles
It is possible to synthesize metal oxides nanoparticles
through the MC reaction, and some of them are
tabulated in Table 2.2.4 [5–11]. In this case, it is very Figure 2.2.19
important to add a dilute agent to the starting mixture. TEM photo of Ni-nanoparticles.

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