Fabrication, microstructure and mechanical properties of Al2O3/Ni nanocomposites by a chemical method

Al2O3/Ni nanocomposites were prepared by a chemical method and hot-pressing technique using AI(NO)(3).9H(2)O and NiO as the starting materials. At 1450 degreesC the composites can achieve >98% theoretical density after hot-pressing. Microstructural results revealed that Ni grains were uniformly dispersed in the Al2O3 matrix, some fine Ni grains of similar to100 nm were entrapped within Al2O3 grains, some Ni grains of 100-300 ran were dispersed at the grain boundary, forming intra/inter-type nanocomposite. The three-point bending strength and the fracture toughness of the dense Al2O3 composite increased by 26 and 79%, respectively, with the addition Ni content. The strengthening and toughening mechanisms of the composite with respect to the microstructure are analyzed. (C) 2003 Elsevier Ltd. All rights reserved.