This work aims to investigate briefly, the effectiveness of plant extracts so far used for steel and other metals as inhibitors in combating the metallic corrosion in basic media. Corrosion inhibitors have been recommended by various researchers as one of the ways to slow down the rate of corrosion and to reduce the financial losses associated with it. Corrosion inhibitors can be organic or inorganic in nature. But due to their eco-friendly and regenerative nature, green corrosion inhibitors of natural origin are the preferred candidates as against synthetic inhibitors. Majority of corrosion studies today are focused on the application of plant extracts for corrosion protection in acidic media, whereas alkaline media has been used only in few studies, and yet with little or no recent work. Even the result of this review shows that plant-based inhibitors have been used mostly on steel products, aluminum products, and copper in that descending order for minimizing corrosion in alkaline media, while it has been rarely used on metals such as tin, iron, and zin in the same alkaline media. As a result, it is beneficial to encourage more review and research on the use of plant extracts as corrosion inhibitors in basic media for steel and other metals. And the novelty of this review is based on this concept. Hence, this study is very vital for key players/readers in this field to improve their awareness regarding on how to design extract of plants origin according to their suitability and reproducibility for corrosion protection of metallic structures.
