The Y_3Al_5O_(12)(YAG) nanocrystals were synthesized by ultrasound-assisted and ultrasoundmicrowave-assisted alkoxide hydrolysis precipitation methods. The structures and morphology of the YAG were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and transmission electron microscopy(TEM). The synthesis kinetics of two kinds of YAG nanocrystals was investigated using differential thermal analysis and thermo gravimetric analysis(DTA-TG) at different heating rates in argon gas. The results show that two kinds of YAG precursors have one obvious endothermic peak at 315-600 K. The apparent activation energy of two kinds of YAG precursors was calculated using the Doyle-Ozawa and Kissinger methods, the coefficients of reaction order, frequency factor and kinetic equations were also determined. The average apparent activation energy for the YAG precursor prepared by ultrasound-microwave assisted was calculated to be 80.76 k J·mol-1 higher than the YAG precursor prepared by ultrasound-assisted synthesis(56.56 k J·mol-1).
