Effect of Antimony and Bismuth on the Electrochemical Corrosion of Cast Aluminum–Silicon Alloys in 3% NaCl Solution

Abstract

The corrosion behavior of Al–Si–Bi (up to 0.5 wt.% Bi) and Al–Si–Sb (up to 0.5 wt.% Sb) ternary alloys is studied with the method of polarization curves and scanning electron microscopy in 3% NaCl solution. Current density indices decrease at concentrations of the doping element up to 0.05 wt.% and, thus, the corrosion rate slows down. At higher concentrations of antimony and bismuth, the current density corresponding to the beginning of passivation increases and the active range on potentiodynamic curves reduces. This is indicative of lower corrosion resistance of the alloys.