Preliminary Study on Dimocarpus Longan Peel as Inhibitors for the Pitting Corrosion of 5052-O and 6061-O Aluminium Alloys in Artificial Brine Solution

The effect of dimocarpus longan peel extract on the pitting corrosion of 5052-O and 6061-O aluminium alloys in an aqueous solution of artificial brine has been studied employing open circuit potential (OCP) and cyclic potentiodynamic polarization techniques. Moreover, surface studies such as scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were also applied. The addition of that extract increases pitting potential (Epit) both aluminium alloys, increasing the resistance of pitting corrosion both them. On the other hand, the resistance of pitting corrosion on 6061-O alloy was higher than that of 5052-O alloy during the addition of that extract. The addition of that extract also shifts OCP towards to positive potentials both alloys, which indicates the formation of a passive surface layer on the surface of alloys. On the basis of results, the appearance of pit shows on the surface of 5052-O alloy due to the presence Fe-enrich phase, compared to that of 6061-O alloy. Abstract should be in 100 words (10)