Biomedical Engineering Reference
In-Depth Information
12.12 X-ray diffraction patterns (Philips X'Pert diffractometer, CuKα)of
the NiO-Al system after 20 hours mechanochemical treatment
(Pulverisette 6 Fritsch GmbH mill) with reagent proportions calculated
for intermetallic phase formation of (a) NiAl and (b) Ni
3
Al (Wieczorek-
Ciurowa and Oleszak, 2008).
Figure 12.11b shows the synthesis of Ni
3
Al/Al
2
O
3
composite powder
formed after 20 hours of milling in the system with reactant proportions for
the Ni
3
Al phase. However, after up to 4 hours of mechanical treatment, Ni
and Al were present and after 10 hours milling, NiO was still detectable. It is
assumed that the slower decomposition kinetics of the hydrate of nickel
hydroxocarbonate in comparison to anhydrous Cu
2
(OH)
2
CO
3
is responsible
for this behaviour.
12.6.2 Effects of mechanosynthesis in the NiO-Al reagent
system
The effect of 20 hours mechanochemical synthesis in the NiO-Al reagent
system was to produce a NiAl phase with Al
2
O
3
, when the ratio of the
