MICROSTRUCTURE AND STRENGTH OF CERAMICS PREPARED
FROM POWDERS SYNTHESIZED VIA SIMULTANEOUS
AND SEQUENTIAL DEPOSITION ROUTES
L. I. Podzorova,
A. A. Il’icheva,
O. I. Pen’kova,
G. V. Talanova,
and L. I. Shvoreneva
Translated from Ogneupory i Tekhnicheskaya Keramika, No. 2, pp. 15 – 19, February, 2003.
Sol-gel techniques for simultaneous and sequential deposition of precursor powders for preparation of cera
mics in the ZrO
system are described. The phase composition of ceramics varies with the
method of powder deposition. The intracrystallite arrangement pattern of the secondary phase in the system
obtained via simultaneous deposition route provides the base for a ceramic that is superior in strength charac
teristics to ceramic prepared from ZrO
powders deposited via sequential route.
The physicochemical processes involved in the forma-
tion of ceramics are in many respects determined by the
properties of the solid-state precursor materials — typically,
powders [1 – 4]. The conventional chemical techniques, in
particular, the sol-gel method, allow one to exert control,
within narrow ranges of dispersion, of the chemical and
phase compositions of the synthesized powders. Studies
were reported in the literature [5 – 7] that were concerned
with the effect of precursor powders, obtained under differ-
ent conditions, on the properties of ceramics. It was shown in
 that the order in which components are deposited during
the synthesis of zirconia and yttria powders affects the phase
composition of the ceramic and the stability of the tetragonal
This work follows in the footsteps of previous studies
[5, 8, 9] concerned with the synthesis of powders in the
system, which is of special interest for
designing dispersion-strengthened engineering ceramics
[8 – 12].
Our goal in this work was to see how the order in which
precursor powder components in the ZrO
system are deposited affects the microstructure and mechani
cal properties of the ceramic prepared from them.
The precursor powders were synthesized as recommended
in [13, 14]. Powders of variable composition (88 mol.% ZrO
+ 12 mol.% CeO
=90/10, 70/30, and 30/70 mol.%
The techniques used were:
a) sequential deposition of components: first hydroxides
of zirconium and cerium were deposited; next, a solution of
aluminum nitrate was added to deposit quantitatively alumi-
num hydroxide (the powders thus obtained were labeled P10,
P30, and P70);
b) simultaneous precipitation of all the hydroxides (the
powders thus obtained were labeled O10, O30, and O70);
Specimens with dimensions of 4 ´ 4 ´ 32 mm were
molded by dry pressing using a hydraulic press (50 tons) at a
specific pressure of 100 – 200 MPa.
The specimens were sintered in air at 1550 – 1650°C
using an electric furnace with chromite-lanthanum heaters.
A low-temperature adsorption method was employed to
measure the specific surface of powders (an Autosorb-1 in
strument was used).
A DRON-3 x-ray diffractometer (CuK
used to analyze the phase composition; JCPDS International
standard databank files were for identification. The quantita
tive phase analysis was carried out using external standards
which were single-phase specimens with a high degree of
Microscopic studies of the structure were conducted on
an MeF3 metallurgical microscope (Reihert) in a reflected
polarized light using polished sections.
Refractories and Industrial Ceramics Vol. 44, No. 4, 2003
1083-4877/03/4404-0211$25.00 © 2003 Plenum Publishing Corporation
Institute for Physicochemical Problems of Ceramic Materials,
Russian Academy of Sciences, Moscow, Russia; Institute for
Glass Joint-Stock Company, Moscow, Russia.