Ys. Cho et al., HYDROTHERMAL PREPARATION AND MORPHOLOGY CHARACTERISTICS OF Y3FE5O12, Journal of the American Ceramic Society, 80(6), 1997, pp. 1605-1608
The influences of processing parameters such as mineralizer, temperatu
re, and nonstoichiometry on reaction product and morphology were inves
tigated in the hydrothermal synthesis of yttrium iron garnet, Y3Fe5O12
(YIG). A cubic YIG phase was synthesized successfully under hydrother
mal conditions of 200 degrees C and 6 h from yttrium and iron hydroxid
e coprecipitates obtained by adjusting the pH to 10.5 using NH4OH. The
other mineralizer, NaOH, was not effective in forming the garnet phas
e, Nonstoichiometric compositions utilizing excess Y content tended to
increase the yield of the garnet phase, but did not affect the morpho
logy, Different morphology characteristics were observed by changing t
he synthesis temperature, Isometric YIG particles disappeared at a rel
atively high temperature of 250 degrees C, resulting in irregular star
-shaped particles of YIG due to the preferential orientation during pa
rticle growth.