Plant Extracts: An Overview of Their Corrosion Mitigation Performance against Mild Steel in Sodium Chloride Solution

Many industries face corrosion problems caused by the medium containing chloride ion due to its aggressive nature. The implementation of corrosion inhibitors has been recognized to be the easiest and most inexpensive approach for corrosion mitigation. Plant extracts as inexpensive, nontoxic, and biodegradable materials are found abundantly in nature. The heteroatoms, and polyfunctional groups of the active constituents present in plant extracts, make them potential candidates as corrosion inhibitors for metals. The present review includes a compilation of to-date investigations of aqueous extracts of various parts of plants for the corrosion inhibition of mild steel in the NaCl medium only. The inhibition efficiency of various plant extracts was reported based on electrochemical techniques. The type of action, the mode of adsorption, and the mechanism of inhibition were also explored. The surface characterization and theoretical accepts are explained briefly as a support to the experimental results.