M. Paskevicius et al. / Journal of Alloys and Compounds 481 (2009) 595–599
599
Table 2
results show that the nanoparticles are on average ∼55 nm with
particle polydispersity and a rough surface structure. XRD results
also show that there is little or no oxide contamination which is
beneficial for Al nanoparticle use in the propellant, pyrotechnic and
explosives industries. Deuterium absorption measurements were
unsuccessful at moderate pressures which indicates that pressures
greater than 2 kbar are required to introduce hydrogen into pure Al
nanoparticles greater than 10 nm in size at temperatures ranging
from 77 to 473 K.
Overview of deuterium absorption conditions for the three samples tested as
described in the text. No measurable absorption was observed for any samples at
the conditions indicated.
Sample
Average particle
size (nm)
Deuterium absorption conditions
Pressure (bar)
Temperature (K)
Al in NaCl
40–50
55
1560
298
473
1560
Al (washed)
1875
77
1
917
298
423
1958
Acknowledgements
Al (purchased)
10–22
1900
298
M. Paskevicius would like to thank the Australian government
for the granting of Australian Post Graduate Awards with Stipend
gen into very large ∼150 m Al powder particles, which were very
likely significantly contaminated with oxygen due to handling in
atmosphere. Al surfaces are poor at dissociating molecular hydro-
gen [25,26], and although oxidised AlH3 powder has successfully
prevented H release over a period of decades due to H imperme-
(
APAWS), and the Australian Institute of Nuclear Science and Engi-
neering (AINSE) for the granting of a postgraduate research award
PGRA). C.E. Buckley acknowledges the financial support of the
(
Australian Research Council through REIF grant R00107962 2001,
which enabled the SAXS studies to be undertaken. The authors
acknowledge the facilities, scientific and technical assistance of the
Australian Microscopy & Microanalysis Research Facility at the Cen-
tre for Microscopy, Characterisation & Analysis, The University of
Western Australia, a facility funded by The University, State and
Commonwealth Governments.
able surface layers of Al O3 [27], the benefit of possessing small
2
amounts of oxide at the AlH surface remain unknown, and it is not
3
clear if Al O is better at dissociating molecular H2 than pure Al
2
3
surfaces. As our attempts to hydride Al nanoparticles below 2 kbar
were unsuccessful, it is clear that no significant change in the ther-
modynamic properties compared to the bulk occurs, even at the
10 nm scale, assuming that other factors are favourable for hydro-
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