Low-level sintering aids for highly transparent Yb:Y2O3 ceramics

Excess additives in laser ceramics compromise the physical nature and degrade the laser performance, and should be diminished properly in order to improve the quality of the laser ceramics. In this work, highly transparent Yb:Y2O3 ceramics were fabricated by using low-level ZrO2-MgO as double-sintering aid and vacuum sintering. Morphology and particle size of the ball-milled ceramic powders were studied by using transmission electron microscopy (TEM) and Rietveld refinement. Phase composition, microstructure and optical transmittance of the sintered ceramic samples were investigated by using X-ray diffractometer (XRD), scanning electron microscopy (SEM) and UV-VIS-NIR spectrometer. The optimized additive concentrations were found as low as 0.8 wt% for ZrO2 and 0.075 wt% for MgO, and the corresponding Yb:Y2O3 ceramic sample fabricated had the transparency as high as 79.4% at 1200 nm and 81.5% at 2000 nm. A possible sintering mechanism was proposed and discussed in this paper. It is expected that the elevated laser performance will be produced in this low-level additive induced Yb:Y2O3 transparent ceramics.