Effects of Graphite on the Corrosion Behavior of Aluminum-Graphite Composite in Sodium Chloride Solutions

摘要

A series of different aluminum-graphite composites (Al-Gr), namely pure Al, Al-1%Gr, Al-2%Gr, andAl-3%Gr, was fabricated. The surface of these composites was investigated using optical microscopyto examine the distribution of exfoliated graphite within aluminum. The corrosion behavior of the pureAl and Al-Gr composites after different immersion intervals in 3.5% NaCl solutions was carried outusing cyclic potentiodynamic polarization (CPP), chronoamperometry (CA), and electrochemicalimpedance spectroscopy (EIS). The study was also complimented by scanning electron microscopy(SEM) and energy dispersive X-ray (EDX) investigation. Corrosion measurements indicated that thepresence of Gr and the increase of its content raise the corrosion rate and reduce the polarizationresistance of Al. Increasing the immersion time of the test samples in the chloride solutions beforemeasurements was found to decrease the general corrosion and increase the pitting corrosion.SEM/EDX investigations revealed that the presence of Gr activates the corrosion of Al due to theoccurrence of galvanic corrosion and this effect increases with increasing Gr content.