The Use of Plant Extracts as Green Corrosion Inhibitors: A Review

The corrosion of metals is very important, both economically and environmentally, and is a serious concern. Since the past decades, traditional (chemical) corrosion inhibitors to prevent corrosion have been and are still being used. Although these inhibitors can be said to be a good choice among other protection techniques because of their good efficiency, the toxicity of many of them causes environmental problems, and, due to the change in the laws on the use of chemicals, many of them are no longer allowed. Hence, during the past years, research on green corrosion inhibitors (GCIs) increased and very favorable results were obtained, and now they are very popular. It can be said that biodegradability and easy preparation are their most important factors. Meanwhile, the use of plants, especially their extracts, has been studied a lot. Plant extracts contain compounds that have anti-corrosion properties. In this review, the use of plants as GCIs is investigated, focusing on recent advances in their use. Also, the phenomenon of corrosion, corrosion protection (including coatings, nanoparticles, and chemical inhibitors), and other GCIs are briefly reviewed.