Rapidly fabricating Y2O3 transparent ceramics at low temperature by SPS with mesoporous powder

Fine-grained and dense highly transparent Y 2 O 3 ceramics have been successfully prepared using high sintering activity mesoporous Y 2 O 3 powders without any additive by spark plasma sintering (SPS). The influences of the sintering temperature on microstructure, density, optical, and mechanical properties of SPS-sintered Y 2 O 3 ceramics were studied in detail. As results, the optimal Y 2 O 3 ceramics with high relative density of 99.90% and fine average grain size of 140 nm were obtained at a low sintering temperature of 1140°C and a moderate load pressure of 60 MPa for 5 min. Meanwhile, the dense Y 2 O 3 ceramics with 1 mm thickness after annealing show a high linear transmittance of 78% (close to 94% of the theoretical value) at 2.4–3 µm wavelength. In additions, the Vickers hardness and fracture toughness of samples can reach 8.48 GPa and 1.45 MPa m 1/2 , respectively. This result proves that the high activity of mesoporous Y 2 O 3 is considered to be an important means for preparing high-performance fine Y 2 O 3 ceramics at low sintering temperature.