Sintering of High-Strength Dense Al2O3 Using Rod-Like Submicron Al2O3 as Sintering Aid

Rod-like submicron Al(2)O(3) powder was prepared by the controllable hydrolyzation of aluminium isopropoxide in streams atmosphere. XRD data show the rod-like Al(2)O(3) has a gamma- Al(2)O(3) structure. TEM images display the length of the submicron Al(2)O(3) is in the range of 100-300 nm and the slenderness ratio is above 10. The rod-like Al(2)O(3) powder was added into the submicron Al(2)O(3) (D(50) = 0.5 mu m, purity > 99.99%) to increase the bending strength of the sintered body and to decrease the sintering temperature. SEM images display that the Al(2)O(3) sintered at 1450 degrees C with rod-like Al(2)O(3) added has a higher density than the virgin Al(2)O(3) and the Al(2)O(3) grains have the trans-crystalline fracture. The bending strength of the sintered Al(2)O(3) with 5 wt% rod-like Al(2)O(3) added is 205 MPa, which increases 241%. A sharp shrinkage in 1300-1400 degrees C appeared in the sintering shrinkage curves characterized by DIL show the rod-like Al(2)O(3) also acts as the sintering aid.