Reduce synthesis temperature and improve dispersion of YAG nanopowders based on the co-crystallization method

• YAG nanopowders were synthesized through a co-crystallization method.
• A three-layer core–shell structure was made to lower the synthesis temperature.
• PAA again reduced the synthesis temperature based on the core–shell structure.
• YAG nanopowders were synthesized at 700 °C in normal apparatus.
• Agglomeration was greatly improved by PAA.

Pure yttrium aluminum garnet (YAG) nanopowders were synthesized at 950 °C from the co-crystallization precursor of Y(NO3)3⋅6H2O and Al(NO3)3⋅9H2O (nitrate process). When 17 wt.% of Y(NO3)3⋅6H2O was replaced by Y2O3 nanopowders, so as to make up a three-layer core–shell structure of the precursor, the synthesis temperature was reduced to 850 °C (Y2O3 process). Based on Y2O3 process, further reducing the synthesis temperature to 700 °C was realized by adding polyacrylic acid (PAA, 50% M), which was used to shorten the distance of the metal ions and provide combustion heat (PAA process). TEM characterizations indicated that the powders produced through nitrate and Y2O3 processes agglomerated, while the powders produced through PAA process were dispersed much better. The agglomerate size analysis results demonstrated that the powders produced through PAA process were with smaller agglomerate size and wider agglomerate size distribution than those through nitrate process or Y2O3 process. And they were more likely to be sintered to YAG transparent ceramics.