Effect of cathodic charging on Al-32Si-2Cu alloy in acidic solution

Abstract

Samples of Al-32Si-2Cu intermetallic was subjected to electrochemical cathodic charging and corrosion test in hydrochloric acid (HCl) solution of concentrations ranging from 0.1 to 3.0 M. The influence of cathodic charging current density and time on changing the surface morphology, phase transformation, compositions, and fracture mode has been investigated using X-ray diffraction (XRD) and scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS). A considerable drop in Vickers microhardness value with increasing cathodic charging time of the specimen was observed. Electrochemical polarization facilitates the formation of simple and mixed salt (AlCl3, Al5Cl3(OH)12.2H2O) over the alloy surface by chloride inclusion in the major corrosion product of hydroxides or oxides of Al.

Keywords

• cathodic charging
• potentiodynamic polarization
• Al-32Si-4Cu alloy