Corrosion is a destructive process where metals deteriorate through reactions with their environment, posing major challenges to infrastructure, industry, and heritage structures. This issue is particularly severe in coastal regions due to the influence of natural seawater. In recent years, plant extracts have been proven to be eco‐friendly, cost‐effective corrosion inhibitors because they are biodegradable, renewable, and nontoxic. Plant extracts have been studied as corrosion inhibitors for numerous metallic materials such as aluminum and its alloys, carbon steel, zinc and its alloys, copper and its alloys, and nickel and its alloys under different aggressive corrosion environments. The present study investigates the corrosion inhibition efficiency of Bougainvillea extract on high‐yield strength deformed (HYSD) steel bars exposed to natural seawater. Electrochemical techniques such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) were used to evaluate inhibition performance. Results showed that inhibition efficiency increased with inhibitor concentration, peaking at 92% for 750 ppm, while a lower efficiency of 87% at 500 ppm was attributed to chloride‐induced film dissolution. Additionally, the adsorption isotherm follows Langmuir adsorption. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of functional groups in the Bougainvillea extract responsible for bonding interactions that contribute to corrosion inhibition.
Bhandary et al. (Thu,) studied this question.