Effect of Cu content on the Electrochemical Corrosion Behavior of Peak-aged Al-6Si-0.5Mg Alloys in Sodium Chloride Solution

Abstract

The purpose of this study is to understand the electrochemical corrosion behavior of 1wt% Cu content Al-6Si-0.5Mg alloy in 0.1M NaCl solution. The potentiodynamic polarization curves reveal that 1wt% Cu content alloy is less prone to corrosion than the Cu free alloy. The EIS test results show that corrosion resistance or polarization resistance (R_ct) increases with the addition of 1wt% Cu to Al-6Si-0.5Mg alloy. Higher polarization resistance (R_p) has been obtained with the addition of 1wt% Cu to the Al-6Si-0.5Mg alloy. Due to addition of Cu and thermal modification, the magnitude of open circuit potential (OCP), corrosion potential (E_corr) and pitting corrosion potential (E_pit) of Al-6Si-0.5Mg alloy in NaCl solution were shifted to the more noble direction.