ISSN 0020-1685, Inorganic Materials, 2007, Vol. 43, No. 5, pp. 502–504. © Pleiades Publishing, Inc., 2007.
Original Russian Text © P.P. Fedorov, E.A. Tkachenko, S.V. Kuznetsov, V.V. Voronov, S.V. Lavrishchev, 2007, published in Neorganicheskie Materialy, 2007, Vol. 43, No. 5,
pp. 574–576.
Preparation of MgO Nanoparticles
P. P. Fedorov, E. A. Tkachenko, S. V. Kuznetsov,
V. V. Voronov, and S. V. Lavrishchev
Laser Materials and Technologies Research Center, Prokhorov General Physics Institute, Russian Academy of Sciences,
ul. Vavilova 38, Moscow, 119333 Russia
e-mail: tez@rambler.ru
Received September 22, 2006
Abstract—MgO nanoparticles have been prepared via hydroxide precipitation from aqueous solutions, fol-
lowed by the thermal decomposition of the hydroxide. The nanoparticles inherit the platelike shape from the
hydroxide and break into isometric particles upon significant superheating. The particle size of the synthesized
magnesium oxide powders varies from 30 to 75 nm, depending on the annealing temperature.
DOI: 10.1134/S0020168507050111
INTRODUCTION
was obviously caused by recrystallization of the MgO
formed.
Advances in nanotechnology, a relatively young
area of materials research, have led to revision and new
interpretation of earlier known scientific facts. For
example, in earlier studies, if synthesis from dilute
solutions yielded a colloidal solution of a precipitate
with low to zero filterability, this was considered a neg-
ative effect. Conversely, there is now increasing interest
in such substances because the effect in question is con-
nected with the preparation of nanometer- and submi-
cron-sized particles, which possess special properties,
differing from the properties of bulk materials.
EXPERIMENTAL
The starting chemicals used were reagent-grade
magnesium oxide and analytical-grade nitric acid.
Magnesium oxide nanoparticles were synthesized in
two steps: precipitation of magnesium hydroxide, fol-
lowed by calcination at different temperatures until
MgO formation. Magnesium hydroxide was obtained
by adding increments of aqueous ammonia to a magne-
sium nitrate solution until precipitation, with constant
stirring using a magnetic stirrer. The magnesium nitrate
solution (0.207 M) was prepared by dissolving magne-
sium oxide in a threefold excess of nitric acid. The pre-
cipitate was washed with distilled water and dried on
filter paper using a lamp (at a temperature of about 40–
50°C).
An interesting effect was found in studies of the for-
mation of yttria nanoparticles through thermal decom-
position of a basic nitrate hydrate [1–4]: adjusting pre-
cipitation conditions, in particular, using some surfac-
tants, one can obtain precursor particles in the form of
nanometer-thick platelets. The Y2O3 particles resulting
from subsequent thermal decomposition of the precur-
sor inherit the platelike shape from the precursor parti-
cles. Considerable superheating causes the platelets to
break into spherical nanoparticles, which is accompa-
nied by a reduction in lattice microstrain to almost zero.
The samples thus prepared were characterized by
x-ray diffraction (XRD). In particular, we evaluated the
size of coherent scattering domains (CSDs) and lattice
microstrain ε as described by Jiang et al. [7]. XRD pat-
The purpose of this work was to ascertain whether terns were collected on a DRON-4 powder diffractome-
this mechanism of nanoparticle formation is universal. ter (CuKα radiation, pyrolytic graphite monochroma-
The model systems used were magnesium hydroxide
and magnesium oxide. Magnesium hydroxide has a
layered, brushite-type structure [5] and typically con-
sists of platelike particles. Magnesium oxide (peri-
clase) crystallizes in cubic symmetry (NaCl structure);
platelike particles are uncommon for MgO. Rao and
Pitzer [6] reported that the DTA curve of Mg(OH)2
tor). Polycrystalline silicon (220 reflection, 2θ =
47.34°) was used as a peak-shape standard. The CSD
size and ε in magnesium oxide were determined by ana-
lyzing the 200 diffraction line profile (2θ = 42.98°). The
morphology of powder specimens was examined by
scanning electron microscopy (SEM) on a JEOL 5910.
To prevent surface charging, a gold layer was evapo-
showed, in addition to the endotherm due to hydroxide rated on the surface of the specimens. Thermal analysis
decomposition, an exothermic peak near 560°C, which (DTA + TG + DTG) was performed at a heating rate of
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