Synthesis of pure YAG nano powders by co-precipitation method

Nano-sized powders of aluminum yttrium garnet (nano-YAG) have been successfullysynthesized by regular co-precipitation method using ammonium hydrogen carbonate (AHC)as the precipitant solvent. To investigate the effect of calcination time, the dried powders werecalcined in a conventional furnace at ۱۱۰۰ °C for various durations i.e. ۱۵, ۳۰, ۴۵, ۶۰ and ۱۲۰min. The phase transformation and micro-structural features of the crystalline samples werecharacterized by X-ray powder diffraction and field emission scanning electron microscopy(FESEM) techniques, respectively. Thermal analysis of samples was investigated bydifferential thermal analysis and thermal gravimetric analysis (TG/DTA). It was found thatcalcination time play an important role in the aluminum yttrium garnet synthesis process. Xraypowder diffraction pattern indicated that the pure YAG phase was synthesized viacalcination at ۱۱۰۰ °C for ۱ hour. Shorter calcination time leaded to appearances of YAM(Y۴Al۲O۹) and YAP (YAlO۳) peaks (accompanied by strong peaks related to crystalline YAGphase). The phase transformation and decomposition stages of precursor powders wereproposed based on TG/DTA results during heating process up to ۱۲۰۰ °C. Moreover, FESEMimages revealed that the average particle size of pure YAG (after ۶۰ min of calcination) wasabout ۵۰-۶۰ nm.

Keywords:

YAG , Nano-sized powder , Synthesis , Co-precipitation method