Abstract: The low-agglomerated single-phase YAG nanopowders were synthesized by the microwave homogeneous precipitation in the presence of urea. The composition and transformations during
calcination of YAG precursor were analyzed by IR, DTA/TG and XRD. The size and morphology of YAG powders were characterized by LD and TEM. Results show
that the amorphous precursor crystallizes directly to single-phase YAG powders upon calcining to 900℃ that was synthesized under [urea]/[metal ions]
molar ratio of 15. The size distribution and sinterability of YAG powders are obviously improved by adding (NH₄)₂SO₄ into the reaction solution.
YAG powders obtained from the precursor with the (NH₄)₂SO₄ content of 8% have good sinterability and can be highly densified at 1500℃.

Key words: microwave homogenous synthesis, YAG powders, sinterability, （NH₄）₂SO₄