IR-transparent Y2O3 ceramics: Effect of zirconia concentration on optical and mechanical properties

Y 2 O 3 transparent ceramics with different amounts of ZrO 2 were obtained by reactive vacuum sintering at a relatively low temperature of 1735 °C for 22 h. The influence of ZrO 2 concentration within the 0–15 mol.% range on the microstructure, phase composition, microhardness, and optical properties of ceramics in the visible and IR ranges was investigated. SEM and XRD results indicate the absence of secondary phases in the studied concentration range, indicating the formation of single-phase solid solutions. It was shown that doping by ZrO 2 considerably decreases the average grain size of ceramics, while microhardness has the opposite behaviour. 15 mol.% ZrO 2 -doped Y 2 O 3 ceramics demonstrated the highest transmittance in the visible wavelength range. On the other hand, 5 and 7 mol.% ZrO 2 -doped Y 2 O 3 could be considered promising materials for the first atmospheric window (3–5 μm). • Transparent Y 2 O 3 ceramics was obtained by vacuum sintering at 1735 °C. • Effect of ZrO 2 (0–15 mol.%) on properties of Y 2 O 3 ceramics was studied. • Non-linear changes of the lattice constant caused by different defects. • 15 mol.% ZrO 2 -doped Y 2 O 3 ceramics has the highest microhardness. • Transmittance of 80.4 % was achieved for 15 mol.% ZrO 2 -doped Y 2 O 3 ceramics.