Novel synthesis of Y3Al5O12 (YAG) leading to transparent ceramics

A YAlO3 (hexagonal) solid solution with a=0.3678 nm and c=1.046 nm crystallizes at 880–935°C from an amorphous material prepared in the mole ratio Y3+/Al3+=3:5 by a sol–gel technique using hydrazine. The hexagonal YAlO3 phase transforms to Y3Al5O12 (YAG) at 1005–1075°C. The YAG powder calcined at 1200°C can be densified to transparency under vacuum for 2 h at 1600°C without additives.