ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 7, pp. 1057!1061. + Pleiades Publishing, Inc., 2006.
Original Russian Text + L.V. Morozova, A.E. Lapshin, I.A. Drozdova, 2006, published in Zhurnal Prikladnoi Khimii, 2006, Vol. 79, No. 7, pp. 1067!
AND INDUSTRIAL INORGANIC CHEMISTRY
Effect of Mechanochemical Activation on the Synthesis
and Sintering of Solid Solutions Based on ZrO
L. V. Morozova, A. E. Lapshin, and I. A. Drozdova
Grebenshchikov Institute of Silicate Chemistry, Russian Academy of Sciences, St. Petersburg, Russia
Received December 19, 2005; in final form, April 2006
Abstract-The effect of mechanochemical activation on the synthesis of tetragonal solid solutions in the
and also the possibility of preparing the substances in amorphous
and nanocrystalline states were studied.
Achievements of the last decade in the field of
ceramics processing and sintering theory clearly show
that the possibilities for the development of new
ceramic materials based on oxides and their com-
pounds are far from being exhausted. Presently there
is an increased interest in ultradispersed powders
(particle size up to 150 nm) in the processing of struc-
tural ceramics, caused by their high activity allowing
compact products to be obtained at relativelly low
sintering temperatures (1400oC).
Structural ceramics based on partially stabilized
zirconium dioxide belongs to new advanced kinds of
ceramics with a unique combination of properties:
high melting point, reagent and corrosion resistance,
high hardness and strength, resistance to thermal
shock, and low thermal conductivity .
To obtain ultradispersed powders, precursors of
stabilized zirconium dioxide, chemical methods of
synthesis (coprecipitation , decomposition of
solutions by evaporation [6, 7], and the sol3gel meth-
od ) are widely used.
The sol3gel method and chemical precipitation
make it possible to synthesize nanopowders (335 nm)
of stabilized ZrO
; however, these methods are rather
labor- and time-consuming; they and also require
special research and a choice of optimal conditions for
each particular system. Such powders tend to form
many-particle agglomerates negatively affecting the
densification in the course of compaction and sinter-
ing of ceramic materials.
At present the method of mechanochemical activa-
tion (MA) is used to accelerate syntheses of solid
solutions and compounds in oxide systems, and also
to prepare ultradispersed powders. This method is
highly competitive with liquid-phase synthetic meth-
ods and allows chemical processes to be performed at
relatively low temperatures when the formation of a
perfect crystal structure is complicated. This opens up
a way to the synthesis of substances in nanocrystalline
and amorphous states. The MA method is character-
ized by simplicity and low cost; thus, it can be con-
sidered as an alternative to modern chemical synthetic
Its essence consists in carrying out solid-phase reac-
tions in grinding devices (mills and disintegrators).
A joint mechanical treatment leads to crushing and
plastic deformation of substances, acceleration of
mass transfer, and efficient mixing of the components.
The mean particle size of ceramic materials obtained
by MA is as small as 303150 nm at a contamination
of no more than 0.05 wt %; the advantages of the
solid-phase synthesis in this case are preserved .
The aim of this work was to study the effect the
mechanochemical activation on the synthesis and sin-
tering of the tetragonal solid solutions (ZrO
prepare compact ceramic materials based on them.
Zirconium, yttrium, and cerium nitrates: ZrO.
O (analytically pure grade), Y(NO
O (chemically pure grade), and Ce(NO
(analytically pure grade) were chosen as starting re-
agents for the study.
The use of hydrated nitrates is caused by the fact
that their hardness is several times lower than that of
the anhydrous compounds, which allows us to reduce