Machines designed to operate in marine environment are generally vulnerable to failure by corrosion. It is therefore imperative
that the corrosion susceptibility of such facilities is evaluated with a view to establishing mechanism for its mitigation. In this
study, the corrosion behaviour of as-cast and retrogression-reagion (RRA) specimens of aluminum alloy containing 0.4–2.0
percent magnesium additions in NaCl, FeCl3, and EXCO solutions was investigated. The corrosion simulation processes involved
gravimetric and electrochemical techniques. Results show substantial inducement of Mg2Si precipitates at a relatively higher
magnesium addition, 1.2–2.0 percent, giving rise to increased attack. This phenomenon is predicated on the nature of the Mg2Si
crystals being anodic relative to the alloy matrix which easily dissolved under attack by chemical constituents. Formation of Mg2Si
intermetallic without corresponding appropriate oxides like SiO2 and MgO, which protect the precipitates from galvanic coupling
with the matrix, accentuates susceptibility to corrosion.