Preparation, thermal stability and sintering behavior of Ni/Al2O3 coated powders

Alumina-coated Ni powders were prepared by a heterogeneous precipitation me thod. The thermal stability of the coated powders was investigated by diffe rential thermal and thermogravimetric analysis in air and argon, respective ly. It was found that the alumina coating layers could effectively hinder t he oxidation process of the Ni particles. The sintering behavior of the pow ders by hot pressing indicated that the coated powders exhibited a higher s interability than ball-milled powders, and could be fully sintered at as lo w a temperature as 1350 degreesC. The microstructure of Al2O3/Ni composites from coated powders was different from that of convenient-processed compos ites. (C) 2001 Elsevier Science B.V. All rights reserved.