Lawsonialnermis Extract Enhances Performance of Corrosion Protection of Coated Mild Steel in Seawater

¹ School of Ocean Engineering, Universiti Malaysia Terengganu, Malaysia.
² School of Fundamental Sciences, Universiti Malaysia Terengganu, Malaysia.

^* Corresponding author: niksani@umt.edu.my

Abstract

The investigation of coating incorporated with various percentages of henna has been conducted by means of weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy method. Mild steel has been studied at ambient temperature and 50°C in order to examine the effect of temperature. The potentiodynamic polarization measurements indicate that henna extract acts as a mixed inhibitor while the corrosion rate (CR) value decreases as the current density (I_corr) decreases in the presence of 10% henna extract for both temperatures. Surface and protective film analysis have been carried out using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM).The inhibition activity is mainly correlated with the major active functional groups of lawsone. The main components can be found in lawsone structures are phenols O-H, carboxylic acid C=O and alkenes C=C. The morphology of the uninhibited sample shows a rough surface of mild steel as a result of corrosion process and severe damage can be seen. In the presence of henna, a smooth surface of mild steel anda uniform deposition of henna were observed.