Pit initiation and growth control of Al in KSCN solutions

The inhibitive action of a newly synthesized glycine derivative, namely 2-(4-(dimethylamino)benzylamino)acetic acid hydrochloride (GlyD) on pitting corrosion of Al in KSCN solutions was studied. Obtained results were compared with glycine (Gly) itself. Cyclic polarization, potentiostatic and galvanostatic measurements were made, complemented with ex situ scanning electron microscope (SEM) examinations. Cyclic polarization measurements indicated that the presence of Gly and GlyD in aggressive SCN- solutions shifted the pitting potentials to more noble values and decreased the anodic currents in the passive region. Transient studies showed that nucleation of pit takes place after an incubation time (ti). The rate of pit nucleation (ti−1) and growth was found to decrease to an extent depending on the type inhibitor. The SEM images showed that the severity of the pitting corrosion of Al in KSCN solution decreased to an extent depending on type of inhibitor. GlyD was much better than Gly in controlling pit initiation and growth of Al in these solutions.