Selection of different sintering aids and heat-treatment of Y2O3 raw powders for Yb3+:Y3Al5O12 transparent ceramics

La₂O₃, Y₂O₃, ZrO₂, and MgO+TEOS were added as the sintering aid to prepare Yb³⁺:Y₃Al₅O₁₂ transparent ceramics. Pre-calcination was adopted to improve the crystalline quality and morphology of the commercially available Y₂O₃ raw powders. The non-stoichiometricaly doped La₂O₃, Y₂O₃, and ZrO₂ enhanced the grain boundary mobility so fast that abnormal grain growth occurred and pores tended to be enclosed in these grains. It was found that MgO+TEOS had a positive effect on full densification of the Yb:YAG ceramics. The grain boundaries moved moderately so that pores could be eliminated well and meanwhile the grains would not get too large. Laser output experiment was also carried out for the Yb:YAG transparent ceramics.