Low temperature synthesis and structural characterization of nanocrystalline YAG prepared by a modified sol-gel method

Nanocrystalline yttrium aluminum garnet, Y3Al5O12 or YAG, was synthesized by means of a modified glycolate or sol-gel method that consists of a mixture of salts in an aqueous media. The monophasic nanocrystalline YAG was obtained at 800 °C, which is much lower than others prepared by wet-chemical methods and little higher than alkoxide sol-gel process. The structural evolution features of the nanocrystalline powder were studied by XRD, FT-IR, 27Al MAS NMR, AFM, SEM and TEM. The crystallite sizes range from 26 to 95 nm for 800 and 1150 °C, respectively, suggesting the possibility to be controlled by the annealing temperature. The experimental results indicate the existence of oxygen defects and Al atoms with distorted or incomplete coordination sphere. The feasibility of the modified glycolate method for the preparation of nanocrystalline YAG is discussed.