Microstructure and mechanical properties of Ni-P coated Si3N4 reinforced Al6061 composites

Silicon nitride is currently a popular choice as reinforcement to develop light alloy composites owing to its high hot hardness and excellent wear and corrosion resistance. However, meager information is available as regards the development of aluminum alloy-silicon nitride composites by stir cast technique. This route of processing metal matrix composites (MMCs) poses challenges in particular, poor wettability of the ceramic reinforcement in the matrix alloy. To overcome this problem, researchers are currently focusing on use of metallic coated ceramic reinforcement. In the light of the above, this paper discusses the development of Ni-P coated silicon nitride reinforced Al6061 composites by stir cast method. XRD, metallographic, EDAX studies, microhardness, and tensile strength tests of the developed composites have been carried out. A maximum of 10 wt% of Ni-P coated silicon nitride has been dispersed uniformly in the matrix alloy. A drastic improvement in both microhardness and tensile strength is observed. (C) 2008 Elsevier B.V. All rights reserved