LAUSR

Abstract YAG precursors were synthesized via a surfactant-free co-precipitation method using ammonium hydrogen carbonate as precipitant. The effect of final pH on Y/Al molar ratio was investigated. Moreover, the effects of excess aluminum ion content on the phase evolution and characteristics of YAG powders synthesized at pH value of 8 were explored. The chemical composition of the precursor, the phase transformation process and the characterization of the products were investigated by means of ICP, XRD, FTIR, TG-DTA, BET, FESEM, TEM and EDX analysis. The results showed that relatively high Y/Al ratio reduced the kinetics of YAG transformation and decreased homogeneity of the precursor while low Y/Al ratio did not alter the process features. Pure YAG nanopowders with particles mean diameter of 45 nm were obtained by calcination at 1000 °C for 2 h, with the addition of 15% mole of the excess aluminum source at pH value of 8.