Synthesis of monodispersed nanometer-sized YAG powders by a modified coprecipitation method

Nanometer-sized yttrium aluminum garnet (YAG) powders were synthesized by using the coprecipitation method with ammonium hydrogen carbonate as a precipitant. The results indicated that an extremely loose YAG precursor was obtained when iodine was introduced in the coprecipitation process on the condition that the initial concentrations of Y³⁺ and Al³⁺ in the solution were set at 0.018 and 0.03 mol/L, respectively, and pH=8. Consequently, the resulting YAG powders after calcination at 1173 K for 2 h were composed of monodispersed particles with an average grain size of 30 nm and better sinterability. The present results indicated that the modified coprecipitation method, with iodine as an additive, was superior to the conventional coprecipitation method, to synthesize ultrafine YAG powders.