Application of Natural Product Extracts as Green Corrosion Inhibitors for Metals and Alloys in Acid Pickling Processes-A review.

Acid solutions are widely used in process industries as inhibitors for the removal of deposited scales from metallic surfaces. Generally the applications of corrosion inhibitors have been an accepted practice for their aggressive nature towards acids. A variety of organic compounds were studied for investigating their corrosion inhibition potential. Literature reveals that the presence of N, S and O in these organic compounds reported excellent inhibition efficiency. But, unfortunately they have the undesired toxic effect on environment, aquatic and animal life and expensive as well. Therefore, plants and natural product extracts have been posed to achieve the target of employing as a cheap, environmentally acceptable, abundant source, readily available and effective molecules having very high inhibition efficiency and low or zero environmental impact. This article discusses properties, adsorption and inhibition mechanism and the efficiencies of natural products which are used as co-friendly corrosion inhibitors for various metals and alloys in different acid media.