Heterocyclic compounds and hybrid materials: green corrosion inhibitors for ferrous and non-ferrous materials

Abstract

With growing environmental awareness and changing regulations that restrict conventional corrosion inhibitors due to their toxicity, corrosion inhibitors are becoming interesting. Many organic compounds containing heteroatoms such as phosphorus, sulphur, oxygen and nitrogen are remarkably effective at inhibiting corrosion. The heteroatoms with the best corrosion-inhibiting properties follow the order P > S > N > O. Their effectiveness is attributed to the inclusion in the molecule of a lone pair and pi electrons, which facilitate their deposition on the metal surface. Extensive research has shown that virtually all corrosion inhibitors contain one or more heteroatoms, often in the form of polar functional groups, which enhances their propensity to adsorb to metal surfaces. Since then, much research on the use of N, P and S atoms has been published, but studies on the use of oxygen, oxygen–nitrogen and oxygen–nitrogen-sulphur heteroatoms are rare. Therefore, the aim of this study was to describe a variety of corrosion inhibitors containing oxygen, oxygen–nitrogen and oxygen–nitrogen-sulphur heteroatoms.