Effects of high-energy ball milling of commercial Y2O3 powders on their densification using spark plasma sintering

Commercial Y2O3 powders were treated by high-energy ball milling (HEBM) and then subjected to spark plasma sintering (SPS) in a furnace at 1600 degrees C under 30 MPa for 5 minutes to produce pure Y2O3 transparent ceramics. The sintered Y2O3 bodies show a relative density of about 99.52% and a grain size of about 3.2 mu m, which is approximately six times smaller than that of the specimen obtained using commercial powders. This result shows that HEBM is highly effective in improving the sinterability of Y2O3 with the controlled grain growth. The transmittance of all sintered specimen was similar in the infrared region (2000 nm), but the specimen that underwent HEBM showed excellent transmittance in the visible light region (700 nm). In particular, the hardness and fracture strengths of the sintered bodies that underwent HEBM were 8.48 GPa and 0.91MPa.m(1/2), respectively, demonstrating excellent mechanical characteristics.