Compression and corrosion behaviour of sintered copper-fly ash composite material

Abstract

An attempt has been made to reinforce Copper (Cu) with low density material Fly Ash (FA) to form Cu–FA composite material through Powder Metallurgy (P/M) route. Samples of 3, 6 and 9 weight percentage of FA in Cu matrix were prepared. Scanning electron microscopy analysis was used to study the morphology of the composite materials. The x-ray diffraction analysis was used to characterize the elemental composition of composite powder. Energy-dispersive spectroscopy (EDS) mapping was used to find the homogeneous distribution of FA in Cu matrix. Mechanical behavior of the Cu–FA composite material was studied using Vickers hardness and compression test. The mechanism model for decrease in compressive strength of Cu–FA composite material was identified as boundary slip. The corrosion behavior of Cu–FA composite material in acidic (1N HCl) and in sea water media are studied. Electrochemical polarization test was used to carry out the corrosion studies on Cu–FA composite material in acidic media. The increase in Polarization Resistance (Rp = 68.6499 × 10−4 Ω cm2 in acidic media and Rp = 68.75327 10−4 Ω cm2 in sea water) of Cu-9FA evidences that increase in weight percentage reinforcement of FA in Cu matrix decreases the corrosion rate in both acidic and sea water media. The increase in charge transfer resistance (Rct = 1142 Ω cm2) of Electrochemical Impedance Spectroscopy (EIS) test authenticates that the corrosion resistance of Cu-9FA is healthier than pure Cu. It was observed that improved corrosion resistance and good mechanical properties are obtained for 9% FA reinforced Cu composite material.