Fabrication of Y2O3 transparent ceramics by hot isostatic pressing from precipitated nanopowders

Yttrium (Y2O3) nanopowders were synthesized via the precipitation method using ammonium hydrogen carbonate (AHC) as the precipitant. The influences of calcination temperature on the composition and morphology of the powders were investigated. Fine Y2O3 powders with low-agglomeration were obtained by calcining the precursor at 1100 degrees C for 4 h. The primary crystallites were calculated to be similar to 47 nm in size and weakly agglomerated to particles with size of similar to 79 nm. Using the synthesized powders as the starting materials, Y2O3 ceramics were fabricated by vacuum sintering at different temperatures combined with HIP post-treatment. The densification and micro-structure evolution of the Y2O3 ceramics were systematically investigated. The ceramic sample vacuum sintered at 1500 degrees C for 2 h and post-HIPed at 1550 degrees C for 3 h exhibited a uniform and fine microstructure with the average grain of about 1.0 mu m. The in-line transmittance of the ceramic sample reached 80.1% at 1100 nm.