PRODUCTION OF NANOPOWDERS
OF YTTRIUM-ALUMINUM GARNET BY THE PECHINI METHOD
A. V. Belyakov
and N. A. Kulikov
Translated from Novye Ogneupory, No. 2, pp. 37 – 38, February, 2011.
Original article submitted December 15, 2009.
Results are presented from the synthesis of nanopowders of yttrium-aluminum garnet by the Pechini method.
It is established that the Pechini method is a promising technology for producing optically transparent ceram-
Keywords: nanopowder, yttrium-aluminum garnet (YAG), Pechini method, transparent ceramic.
In 1967, Pechini patented a method of obtaining very
fine powders by using chelate complexes.
Due to its sim-
plicity, low cost, and flexibility under industrial conditions,
this method is now also used to obtain nanopowders. The
Pechini method is not highly sensitive to moisture (at least
for most substances), does not require an inert atmosphere or
strict monitoring of firing temperature and time, and is con-
venient to use for the synthesis of multi-component oxide
systems. Among the advantages of the method are the possi-
bility of controlling stoichiometry, forming a homogeneous
mixture of components and single-phase powders, and form-
ing films at low temperatures with short periods of time for
nanopowder synthesis. A diagram of the Pechini method is
shown in Fig. 1.
To use the Pechini method for synthesis, it is necessary
to have multifunctional organic acids capable of forming sta-
ble chelate complexes with metal ions. It is also necessary to
have diatomic alcohols, which are used as solvents in the ini-
tial stages of the synthesis operation and are used as reagents
for polyesterification in subsequent stages. The poly-
esterification reaction helps form a polymer that consists of a
polymeric three-dimensional network with interstitial metal
As a rule, in the first stage, sols of the corresponding
metals are dissolved in a large excess of citric acid to form
citrate complexes. Ethylene glycol is added to the resulting
solution, which is then heated to 100 – 130°C in order to syn-
thesize a polyester between the free citric acid and the ethyl-
ene glycol. Temperature is then increased to remove excess
alcohol. The resulting viscous substance (polymer) is kept at
450 – 600°C to remove products formed in the oxidation of
the organic matter that is present. The thus-synthesized mate-
rial is a mixture of uniformly distributed oxides of metals
and intermediate decomposition products. Subsequent heat
treatment makes it possible to obtain a final product of the
In the course of the experiments that were performed, the
Pechini method was used to synthesize powders of
(yttrium-aluminum garnet — YAG). Accord-
ing to data obtained from scanning electron microscopy, the
product was characterized by particle sizes of less than 1 mm,
and in certain cases particle size was as small as 50 nm.
However, synthesis of the YAG particles also showed some
of the shortcomings of the method. Among the problems
were the presence of organic matter after heat treatment, ag-
gregation of the particles, and incomplete removal of carbon
from the particles. The phenomenon of powder particles in-
heriting the structure of the previous material is manifest
clearly in synthesis through the stage of aerogel formation:
after heat treatment, the particles replicate the structure of the
It was established that the polymer must be heat-treated
for a longer period of time and at higher temperatures in or-
der to reduce the amount of organic material left in it after
the synthesis operation. However, increasing heat-treatment
time and temperature adversely affects the structure of the
powder; denser aggregates are formed and residual carbon
Refractories and Industrial Ceramics Vol. 52, No. 1, May, 2011
1083-4877/11/05201-0061 © 2011 Springer Science+Business Media, Inc.
D. I. Mendeleev Russian Chemical-Technological University,
U. S. Patent No. 3.330.697, C1. 117 – 215. Method of preparing
lead and alkaline earth titanates and niobates and coating method
using the same to form a capacitor,” Pechini M. P.; Applicant and
Patent-Holder North Adams, Mass., assignor to Sprague Electric
Company, North Adams, Mass., a corporation of Massachusetts.
— No. 304434; Applied 26.08.1963; Published 11.07.67, 7 pp.