The Al2O3/YSZ samples were prepared with different MgO particle sizes and wt.% ranging from 0.4 wt.% to 0.9 wt.% for micron size of additives and 0.4 wt.% to 1.3 wt.% for nano additives. The powders were then mixed using a ball mill for 8 h and pressed at 295 MPa using a hydraulic press. The specimens were then sintered in a Lenton electric hearth furnace at 1600 C for 4 h with 5 C/min sintering rate.