Effect of Nanosized Al2O3 as Additive on the Sintering Characteristics and Vickers Hardness of Al2O3/Si3N4 Compound Ceramics

In order to enhance the density and decrease the sintering temperature. Al2O3/Si3N4 compound ceramics were sintered by pressureless using beta- Si3N4 as raw materials and Al2O3 as sintering additives. The effects of Al2O3 as additive on the Vickers hardness and the sintering characteristic of Al2O3/Si3N4 compound ceramics were studied. The results shows that adding 9-15% nano- Al2O3 can get Al2O3/Si3N4 compound ceramics only in 1650 degrees C by pressureless sintering because of nano- Al2O3 sintered. As a consequence. the relative density increases from 89% with micro alumina to above 97% with nano- Al2O3. the Vickers hardness increases from 1043.5MPa to 1356.0 MPa.