Study on MgAl2O4-doped Al2O3 ceramics

Influences of MgO doping quantities and sintering conditions on the sinter ability and microstructure of Al2O3 ceramics was investigated, which MgO was doped in the form of MgAl2O4. Sintering at 1640 degrees C in air, the sinter ability of MgAl2O4-doped Al2O3 ceramics was worse than those of MgO-doped Al2O3 ceramics. While sintering at 1640 degrees C in H-2, the sinter ability of MgAl2O4-doped Al2O3 ceramics was better than those of MgO-doped Al2O3 ceramics. The relative density of MgAl2O4-doped Al2O3 ceramics reached 99.1 %, but distribution of grain sizes was heterogeneous, which was grain sizes of 3 mu m similar to 7 mu m. When MgAl2O4-doped Al2O3 ceramics was prepared by fist-step sintering at 1450 degrees C in air, and then final-step sintering at 1640 degrees C in H-2, the dense Al2O3 ceramics with elongated grains was achieved.