Effects of ZrO2 concentration on the properties of pressureless-sintered highly transparent Er2O3 ceramics

Erbium oxide (Er 2 O 3 ) transparent ceramics were successfully fabricated with different contents of zirconia (ZrO 2 ) additive sintered at 1850 °C for 8 h in vacuum. The effects of ZrO 2 concentration on microstructure, optical, mechanical, and thermal properties of Er 2 O 3 transparent ceramics were systematically investigated in this study. With the concentration of ZrO 2 increasing from 0 to 4 at.%, the average grain size of Er 2 O 3 transparent ceramics decreased from 166.6 to 4.7 μm. Also, the Vickers hardness and fracture toughness were increased from 7.6 ± 0.3 to 10.1 ± 0.3 GPa and 0.69 ± 0.05 to 1.09 ± 0.03 MPa m 1/2 , respectively. However, the thermal diffusion coefficient and thermal conductivity reduced slightly after the doping of ZrO 2 . The in-line transmittance of 4 at.% ZrO 2 -doped Er 2 O 3 ceramics with the excellent optical quality reached 77% in the visible range and 78% at 1100 nm, which were 95% and 96% of the theoretical in-line transmittance of Er 2 O 3 single crystal, respectively. There were absorption peaks at 1500 nm and in the visible light range of 4 at.% ZrO 2 -doped Er 2 O 3 ceramics. The Er 2 O 3 ceramics developed in this study can be potential candidates for application in solid-state lasers.