Effect of process parameters on the synthesis of YAG nano-crystallites in supercritical solvent

Nano-scaled aluminum yttrium garnet (YAG) powders with a spherical morphology were prepared by a mixed-solvo-thermal method under moderate reaction conditions using inexpensive starting materials. The effects of the changing process parameters on phase evolution, constitute and morphology of the resulting samples were characterized by X-ray diffraction (XRD), DTA-TG, transmission electronic microscope (TEM) and HRTEM techniques. The results show that pure phase YAG powders can be successfully synthesized at 300 °C for 1 h when the volume ratio of ethanol to water is 2 or larger. The TEM results reveal that the YAG particles synthesized are well-dispersed fine spherical grains with a relatively narrow grain size distribution. Finally, the formation mechanism for solvo-thermal crystallization of YAG grains is proposed based on IR results.