Biomedical Engineering Reference
In-Depth Information
12.11
X-ray diffraction patterns (Philips X'Pert diffractometer, CuK
α
)
for a Ni
2
(OH)
2
CO
3
.
x
H
2
O-Al system after 20 hours of mechanochemical
treatment (
Fritsch GmbH mill) with reagent proportions
calculated for intermetallic phase formation of (a) NiAl and (b) Ni
3
Al
(Wieczorek-Ciurowa and Oleszak, 2008).
Pulverisette 6
12.6.1 Effects of mechanosynthesis in the
Ni
2
(OH)
2
CO
3
.
H
2
O-Al reagent system
The XRD patterns of the Ni
2
(OH)
2
CO
3
.xH
2
O-Al systems with reagent
proportions calculated for NiAl or Ni
3
Al intermetallics mechanically treated
for 20 hours are shown in Fig. 12.11. It is seen that, instead of the desired
NiAl, the Ni
3
Al phase is formed with traces of NiAl. Furthermore, up to the
fourth hour of milling, reagents such as NiO, Ni and Al still remain and
after 10 hours of milling the reaction was still incomplete, about 15% salt
was undecomposed and mechanical alloying of Ni
3
Al was in its first stage.
The results of thermal analysis measurements also confirmed these effects
(Wieczorek-Ciurowa and Oleszak, 2008). After 20 hours of milling the
composite powder is fully formed.
x
