Investigation of Anti-corrosion Effect of Gum Arabic on the Aluminum Corrosion in Alkaline Medium

One of the most important uses of aluminum is alkaline batteries. The main obstacle of such applications is its high corrosion rate.The present work is a trial to overcome the self-corrosion issue of aluminum and find out a cheap, safe and eco-friendly inhibitor. In this research the inhibition effect of Gum Arabic (GA) on the aluminum corrosion in 4 M KOH solution has been investigated by hydrogen evolution test, open circuit potential (OCP), potentiodynamic polarisation and the surface analysis method. The Obtained results showed that GA prevents aluminum corrosion in alkaline media and inhibition efficiency (IE%) enhances with the increase in the concentration of GA and decrease with the increase in the temperature. At the highest concentration of GA (at 25°C) the inhibition efficiency is 75.25%. Also the Kads value reduce with the increase in the temperature, which indicates that inhibitor molecules physically adsorbed on aluminum surface. Due to the presence of significant amount of polar groups in GA structure, it blocks the surface of the aluminum by adsorption onto its surface, prevents its corrosion. SEM and EDAX results showed that in the presence of GA, the corrosion rate is clearly reduced and a stable protective layer cover the aluminum surface. The potentiodynamic polarisation results also indicate that the GA acts as a mixed type inhibitor.