Mechanical and optical properties of spark plasma sintered transparent Y2O3 ceramics

Commercial Y 2 O 3 nanopowder was used to fabricate transparent Y 2 O 3 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 Y 2 O 3 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 Y 2 O 3 ceramic were 122 MPa, 7.60 GPa and 2.06 MPa.m 1/2 , respectively. The Y 2 O 3 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.