Electrochemical investigation of the corrosion behavior of heat treated Al-6Si-0.5Mg-xCu (x=0, 0.5 and 1) alloys

  • Abul Hossain Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka
  • Mohammed Abdul Gafur Pilot Plant and Process Development Centre (PP & PDC), BCSIR Laboratories, Dhaka
  • Fahmida Gulshan Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka
  • Abu Syed Wais Kurny Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka
Keywords: Al alloy, Nyquist plot, corrosion rate, tafel plot, EIS

Abstract

The corrosion behavior of heat treated Al-6Si-0.5Mg-xCu (x=0, 0.5 and 1 wt %) alloys in 0.1 M NaCl solution was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization curves reveal that 0.5 wt % Cu and 1 wt % Cu content alloys are less prone to corrosion than the Cu free alloy. The EIS test results also showed that corrosion resistance or charge transfer resistance (Rct) increases with increasing Cu content into
Al-6Si-0.5Mg alloy. Maximum charge transfer resistance (Rct) was obtained with the addition of 1 wt % Cu and minimum Rct value was for Cu free Al-6Si-0.5Mg alloy. Due to addition of Cu and thermal modification, the magnitude of open circuit potential (OCP), corrosion potential (Ecorr) and pitting corrosion potential (Epit) of Al-6Si-0.5Mg alloy in NaCl solution were shifted to the more noble direction.

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Published
15-03-2015
Section
Electrochemical Science