Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 1, pp. 11−14.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © E.E. Grinberg, G.V. Baranova, I.E. Strel’nikova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 1, pp. 14−17.
AND INDUSTRIAL INORGANIC CHEMISTRY
Inﬂ uence of Hydrolysis Method on the Sol-Gel Formation
of the Yttria–Alumina System with Use of Alcoholates
E. E. Grinberg
, G. V. Baranova
, and I. E. Strel’nikova
Scientiﬁ c-Research Institute of Chemical Reagents and High Purity Chemical Substances, Moscow, Russia
Bochvar All-Russian Scientiﬁ c-Research Institute for Inorganic Materials, Moscow, Russia
Received July 26, 2012
Abstract—The inﬂ uence exerted by hydrolysis methods and introduction of a hydrolyzing agent into the systems
formed by the alkoxide technology, which uses yttrium salts and alumium secondary butylate as the initial com-
ponents, was determined. It was found that the hydrolysis stage affects the conditions of the subsequent thermal
treatment, the phase formation in the system, and the granulometric composition of the prepared powders. The
most favorable conditions for formation of yttrium aluminum garnet are achieved upon excess water hydrolysis
in the presence of an aqueous solution of yttrium salt.
Yttrium–aluminum garnet (YAG) is the most widely
used optical material for the development of solid-state
lasers, including those with unique characteristics. YAG
powder is used for growing single crystals and preparing
transparent ceramic. The material has the cubic structure
and therefore may be activated by rare earth elements,
which can serve as luminescent and catalytic centers.
Among many methods of YAG preparation, the alk-
oxide sol-gel technology using alkoxides of correspond-
ing elements as starting materials and their hydrolysis
to obtain pure oxide hydrates with ﬁ ne particles and a
developed surface area is the most promising method.
Along with the evident advantages, the only alkoxide
method of the preparation of YAG powders has some
drawbacks, such as difﬁ culty of obtaining and purifying of
yttrium alkoxide. Therefore, it is impossible or not reason-
able to use the only alkoxide raw materials for production
of YAG and a number of multicomponent oxide systems.
A cheap and simple method is the alkoxide-salt (hybrid)
sol-gel technology with the use of yttrium as salt .
The yttria–alumina system has three chemically
strong compositions: the stable compositions are cubic
) and monoclinic Y
) and the metastable composition is
). These compounds are
formed successfully. In a complex chain of reactions
between yttria and alumina, the synthesis of garnet is
the fastest reaction.
We studied how the proposed method of the synthesis
using aluminum secondary butylate and yttrium salts
(chloride, nitrate, and acetate) as starting materials is
affected by the hydrolysis, one of the most important
The synthesis was performed in a solution of alumi-
num secondary butylate in isopropyl alcohol (ASB in
IPA) in order to reduce the viscosity of the solution and
to attain a better distribution of the components in the
volume. The yttrium salt, chloride (YCl
O], or acetate [Y(CH
O], was in-
troduced into the solution at continuous intense agitation.
After the introduction of yttrium salt, the system had
strongly acidic pH value, which facilitates formation of
stable ultraﬁ ne particles with minimal tendency to ag-
glomeration and makes further acidiﬁ cation of the sol in
the early stages of its formation unnecessary.
We studied the different methods of the hydrolysis.
The hydrolysis owing to the crystallization water of yt-