Alumina assisted grain refinement and physical performance enhancement of yttria transparent ceramics by two-step sintering

Submicrometer grain-sized (1.5 µm) yttria ceramics exhibited the remarkable flexural strength enhancement from 28.5 to 165.0 MPa, and equivalent or superior transparency (81.8%, 1064 nm) to that of single crystal under the two-step sintering of 1550-1500 °C and Al2O3 additive amount of only 150 ppm.