Fabrication of Transparent Yttria Ceramics by Spark Plasma Sintering

Rapid densification of yttria (Y2O3) ceramics without sintering aids via spark plasma sintering at relatively low temperature of 1300 • C for 40 minutes at two-step pressure profile, followed by post-annealing at 1050 • C for 6 hours in air was attempted.Effect of preload pressure on microstructure, Vickers hardness, fracture toughness and optical in-line transmittance was investigated.Densification during spark plasma sintering did not involve any phase transformation and all phases have shown cubic structure according to X-ray analysis.The highest hardness and fracture toughness value was recorded to be 7.60 ± 0.18 GPa and 1.16 ± 0.07 MPa m 1/2 with 10 MPa preload and 100 MPa final load.In addition to this, the highest transmittance with a value of 76.7% at a wavelength of 2000 nm was obtained when studied with 10 MPa preload and 100 MPa final load.