The green plant-based corrosion inhibitors—a sustainable strategy for corrosion protection

Abstract Corrosion of metals is an inevitable process in nature which is conducted by a spontaneous electrochemical reaction between the corrosive environment and a metallic surface. Globally, there is a significant loss due to corrosion, and therefore, corrosion inhibition is a basic need. The use of traditional methods such as protective coatings and sacrificial coatings have some limitations, being toxic and not eco-friendly. In this context, the plant-based corrosion inhibitors are emerging as novel, eco-friendly and economically viable alternatives for inhibition of corrosion. The present review is focused on the role of plant extracts and biomass for the inhibition of corrosion. In addition, the potential of secondary metabolites produced by the plants and their activity in combination, mechanism of inhibition and patents generated in the field have been discussed. The green anti-corrosive inhibitors have some limitations as these are less efficient at low concentrations. Furthermore, the microbial corrosion should be studied in detail and the efficacy of plant extracts and essential oils should be evaluated in order to develop a proper anticorrosive strategy. Finally, the effect of these active metabolites in combination with other less-toxic chemicals and essential oils may give rise to newer potential synergistic combinations with far-reaching impact.