Fabrication and Evaluation of Corrosion Behavior of Nickel Alloy Metal Matrix Composite with Influence of Chills

Nickel alloys have wide-spread applications in mechanical, tribological and corrosion components such as clutches, cylinder liners, pistons in the automotive industry and marine components in sea water owing to its relative corrosion resistant & good thermal conductivity. The presence of silicon results in reduction of the co-efficient of thermal expansion of nickel & produces an alloy with good casting machining & corrosion characteristics. Further it is reported that addition of silica, improves the mechanical properties which in turn has profound influence on the mechanical properties and corrosion behavior of Nickel-SiO2 alloys. Therefore an investigation in the present research will be made to fabricate and evaluate the microstructure, corrosion of chilled composites consisting of nickel matrix and fused SiO2 particles as the reinforcement (size 40-150 µm) in the matrix. The reinforcement being added ranges from 3 to 12 wt. % in steps of 3%. The resulting composites cast in moulds containing metallic and non metallic chill block (MS, SiC & Cu) were tested for their microstructure and corrosion behaviors. The main objective of the present research is to obtain fine grain Ni/SiO2 chilled sound composite having very good mechanical and corrosion properties.