Protection against Corrosion of Aluminum Alloy in Marine Environment by Lawsonia inermis

The corrosion performance of aluminum alloy 5083 (AA5083) was investigated in the splash zone area simulated in salt spray cabinet at ambient temperature. Three paint formulations were prepared in accordance with different percentages of henna extract. FTIR method was used to determine the constituent of henna while weight loss and electrochemical method were applied to investigate the inhibition behaviour. The findings show that corrosion rate of aluminum alloy decreased with the increases of henna extract in the coating formulation. The rise of charge transfer resistance (Rct) value has contributed to the greater protection of the coated aluminum. The decrease in double layer capacitance value (Cdl) is another indicator that a better protective barrier has been formed in the presence of henna in the coating matrix.