Abstract
Al2O3/Si3N4 composites were prepared by hot-pressing the mixtures of finer Al2O3 and Si3N4 powders at 1600°C in N2 atmosphere. Transmissiom electron microscopic observation revealed that most of Si3N4 particles were dispersed within Al2O3 grains. The fracture toughness of this nanocomposites increased from 3.25 to 4.6 MPam1/2 and the fracture strength showed a similar trend from 350 to 530 MPa. The most striking finding in this composite system was that the degradation in hardness and strength at elevated temperatures were significantly improved by the nanoscale dispersion of Si3N4 into the Al2O3 grains. The effcts of Si3N4 dispersions into Al2O3 grains on the mechanical properties such as hardness, toughness and strength were discussed.
