Low-agglomerated yttria nanopowders via decomposition of sulfate-doped precursor with transient morphology

The fabrication peculiarities of low-agglomerated yttria (Y₂O₃) nanopowders via thermal decomposition of sulfate-doped precursor with transient morphology were studied. It was determined that Y₂(OH)₅(NO₃)_x(CO₂)_y(SO₄)_z·nH₂O (n=1-2) crystalline precursor underwent fragmentation and decomposition into isolated quasi-spherical Y₂O₃ particles upon calcination. Effect was connected with minimizing the free energy of the plate-like crystallites via reducing the contact surface until to the moment of spheroidization and attainment of isolation that occurred at T=1100 °C. Residual sulfate ions slowed down the surface diffusion during heat treatment thus retaining quasy-spherical morphology and low aggregation degree of Y₂O₃ nanopowders. Sulfate-doped yttria nanopowders with medium particle size of 53±13 nm possessed improved sinterability in comparison with undoped ones arising from finer particle size, narrower particle distribution and lower agglomeration degree.