Fabrication of transparent YAG ceramics by traditional solid-state-reaction method

Transparent polycrystalline YAG ceramics were fabricated by solid-state reaction method using commercial ultrafine yttria and α-Al2O3 powders. The starting materials were milled and calcined at 1 400 °C, and sintered into transparent YAG ceramics at 1 750 °C in the vacuum for 4 h. Neither the starting materials as-milled or those calcined into YAG phase at 1 500 °C can be sintered into transparent ceramics. Wide grain boundaries emerge in the YAG ceramics sintered at 1 850 °C for 4 h, at the edge of which YAG phases decompose into perovskite YAlO3(YAP) and α-Al2O3.