The transparent Y₂O₃ ceramic was prepared in this work via vacuum sintering of Y₂O₃ nanopowder obtained by sulfuric acid-assisted calcination. The calcination temperature notably influenced the dispersion, morphology and sinterability of Y₂O₃ nanopowders. The calcined powders at various temperatures showed similar shapes, primarily comprised of round particles with an isotropic surface. Nevertheless, the particle size gradually increased as the calcination temperature was raised. The powder calcined at 1100 ℃ showed a lower agglomerate state (n = 2.19) and better sintering properties instead of those obtained at other calcination temperatures, which can be correlated with a larger specific surface area at the low temperature of <1100 ℃ and the rapid growth of large particles at 1200 ℃, respectively. The powder, calcined at 1100 ℃ was vacuum sintered in transparent ceramics for 5 h at a temperature of 1700 ℃. The transparent ceramic exhibited a dense and uniform microstructure, and the 1.5 mm thick sample has an inline transmission of up to 70% at 800 nm wavelength.

Keywords: Transparent ceramics, Y₂O₃ nano-powders, Calcination temperature, Sulfuric acid.