The Preparation of Al2O3/Ni Nanocomposites by Pressureless Sintering

In the present study, an Al2O3-matrix nanocomposite containing 5 vol.% Ni is prepared by pressureless sintering. Most the Ni inclusions, around 70 vol.% of Ni, locate at the intergranular sites. The presence of the intergranular Ni inclusions prohibits the grain growth of Al2O3 matrix. The size of the intergranular nickel inclusions, 140 nm, is larger than that of the intragranular ones, 70 nm. The strength and toughness of the Al2O3/Ni nanocomposite are 1.35 and 1.2 times that of Al2O3 alone. The strengthening is mainly contributed by microstructural refinement.