Effectiveness of strontium zinc phosphosilicate on the corrosion protection of AA2198-T851 aluminium alloy in sodium chloride solution
Shedrack Musa Gad, Seyedgholamreza Emad, Xiaorong Zhou, S.B. Lyon, Zelong Jin, Ishaya Musa Dagwa
Abstract
The effectiveness of strontium zinc phosphosilicate (SZP 391) as a corrosion inhibitor for the protection of Al–Cu–Li alloy in 0.5 M NaCl solution was evaluated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarisation (PDP). The morphology of substrates were characterised with scanning and transmission electron microscopy (SEM) and (TEM). The corrosion rate of the substrates exposed to uninhibited solution increases with immersion time while those in inhibited solution showed significant reduction of corrosion rate. SEM and TEM revealed presence of film formed on the substrates’ surface which serves as a barrier for blocking the access of aggressive ions.