Mechanical and optical properties of spark plasma sintered transparent Y2O3 ceramics

Commercial Y2O3 nanopowder was used to fabricate transparent Y2O3 ceramics by spark plasma sintering under the pressure of 100 MPa for 20 min with the heating rate of 100 °C/min. The microstructures, mechanical and optical properties of the Y2O3 ceramics sintered at different temperatures were investigated in detail. Densification occurred up to a sintering temperature of 1500 °C, and above 1500 °C, rapid grain growth and pore growth occurred. The highest relative density of 99.58% and the minimum average grain size of 0.58±0.11 µm were obtained at 1500 °C. The flexural strength, hardness and fracture toughness of the optimal spark plasma sintered Y2O3 ceramic were 122 MPa, 7.60 GPa and 2.06 MPa.m1/2, respectively. The Y2O3 ceramic sintered at 1500 °C had the in-line transmission of about 11-54% and 80% in the wavelength range of 400-800 nm and 3-5 µm, respectively.