Synthesis of yttria nanopowder with poly acrylic acid as dispersant for highly transparent yttria ceramics

Highly pure and well-dispersed yttria nanocrystalline powders were synthesized with a modified coprecipitation method that uses mixed ammonium hydroxide-carbonate solution as the precipitant and poly acrylic acid (PAA) as the dispersant. Comparing with the yttria powders synthesized using the same route but without PAA dispersant, the PAA-assisted powders exhibit lower level of agglomeration and better sinterability. Sintering trajectories of the powders with and without PAA dispersant were investigated. Y₂O₃ ceramics sintered with the PAA-assisted powders exhibited smaller grain size, homogeneous microstructure, and higher in-line optical transmittance. The result suggests that the polymer-assisted coprecipitation could be used to synthesize yttria nanopowders for fabricating high optical quality transparent ceramics.