SIMPLE METHOD FOR SYNTHESIZING ALUMINUM-YTTRIUM GARNET
(Nd:YAG) NANOPOWDERS BY FLUSHING (BUBBLING) WITH AMMONIA
X. X. Li,
B. Y. Zheng,
and J. L. Huang
Translated from Novye Ogneupory, No. 6, pp. 52 – 56, June, 2014.
Original article submitted April 1, 2014.
A simple method is developed for synthesizing nanopowder of neodymium-doped yttrium aluminum garnet
(Nd:YAG) by coprecipitation with flushing (bubbling) by ammonia. Different methods are used to study the
specimens obtained, such as thermogravimetry/differential scanning calorimetry, X-ray powder diffraction,
infrared spectroscopy based on a Fourier transform, scanning electron microscopy. Results show that
stoichiometric Nd:YAG powders may be prepared by calcination of a precursor at 900°C for 2 h. In addition, it
is detected that a slow ammonia supply rate (5 – 10 ml/min) is favorable for forming Nd:YAG powders with a
good structure and with an average particle size of ~70 nm. The technology developed by us does not use
manual titration for synthesizing multibasic oxides, as a result of which this technology may be readily used
on an industrial scale.
Keywords: Nd:YAG, coprecipitation, ammonia, powders, ceramic, synthesis.
Due to different optical and mechanical properties of
neodymium-doped yttrium aluminum garnet (Nd:YAG) sin-
gle crystals they are used extensively as solid-state laser sub
stances . Normally Nd:YAG single crystals are grown by
means of a traditional Chokralski method, which is not only
technically complex, but also extremely expensive. It is very
difficult to grow high quality coarse (Nd:YAG) single crys
tals by this method. Recently considerable attention has been
devoted to transparent laser ceramic of Nd:YAG, since it ex
hibits a whole series of advantages, and in fact low cost,
preparation rapidity, high concentration of alloying impuri
ties, size, etc. [2 – 8]. It is well known that in the course of
preparing transparent laser ceramics of Nd:YAG synthesis of
high quality polycrystalline Nd:YAG powder is most impor
tant [9, 10]. Therefore considerable effort is applied in the di
rection of preparing polycrystalline Nd:YAG powder with a
good structure, which may then be used as starting material
for synthesizing polycrystalline ceramic.
Normally Nd:YAG powder is prepared by means of a
solid-state reaction of the corresponding oxide powders. This
method requires a high firing temperature and prolonged
soaking times . Compared with solid-state reactions the
method of wet chemical synthesis has such advantages as not
only a low synthesis temperature and short firing duration,
but also the fact that in the course of their use it is possible to
obtain a uniform mixture of metal ions at an atomic level.
Therefore recently there has been extensive study of several
methods of wet chemical synthesis with the aim of preparing
high quality Nd:YAG powders [3, 12 – 23]. Among these
methods the simplest and cheapest synthesis method is com
bined precipitation, and in order to prepare Nd:YAG powder
such precipitants are used as ammonia water [24, 25] and
ammonium hydrogen carbonate [9, 10, 16]. Normally re
verse titration technology is used in the course of combined
precipitation  in order to prepare stoichiometric Nd:YAG
powder. Metal nitrate solution is added dropwise to precipi
tant. In the course of titration there is formation of excess lo
cal concentration of metal ions, which is unfavorable for
forming uniform Nd:YAG powder. In addition, in the course
of the process supply of droplets normally requires manual
titration, which in turn, leads to uneven droplet supply rate,
and also to the impossibility of using such a method on an in
Refractories and Industrial Ceramics Vol. 55, No. 3, September, 2014
1083-4877/14/05503-0250 © 2014 Springer Science+Business Media New York
Department of Chemical Engineering, College of Environmental
& Biological Engineering, Putian University, Putian 351100, PRC.
Department of Chemical and Biochemical Engineering, College
of Chemistry and Chemical Engineering, Xiamen University,
Xiamen 361005, PRC.