PREPARATION OF AL2O3-ALN-NI COMPOSITES

A method is proposed to prepare Al2O3-AlN-Ni composites, The composite s are prepared by sintering Al2O3/NiAl powder mixtures at 1600 degrees C in a mixture of nitrogen and carbon monoxide. The presence of NiAl particles raises the green density of Al2O3/NiAl powder compacts, Duri ng sintering, NiAl reacts with nitrogen to form AlN and Ni inclusions, A volume expansion accompanies the reaction, Because of the high gree n density and the reaction, the volume shrinkage of the Al2O3-AlN-Ni c omposite decreases with the increase of added NiAl content.