Morphology investigation of yttrium aluminum garnet nano-powders prepared by a sol–gel combustion method

Highly sinterable yttrium aluminum garnet (YAG) nano-powders have been synthesized by a sol–gel combustion method with various chelating agents and fuels, namely citric acid, tartaric acid, glycine and ethylene diamine tetraacetic acid (EDTA). The preparation involved the thermal decomposition of a chelating agent (fuel)–nitrate gel and the formation of amorphous precursors. The as-synthesized precursors were studied by infrared spectroscopy (IR), thermogravimetric (TG) and differential scanning calorimetric (DSC) analyses. The nano-powders calcined at 1000°C were characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). It was found that the chelating agents and fuels used had a significant influence on the average grain size and agglomeration of YAG nano-powders. The rate of combustion reaction between chelating agent (fuel) and nitrate was responsible for the growth of the grains. Nano-particles with the smallest size and high sinterability were obtained when using EDTA, which derived from the significant blocking of the diffusion path associated with the lowest combustion reaction rate.