۱- Introduction

۲- Mechanism

۳- Corrosion inhibitor chemistry

۴- Conclusions and prospects

References

Abstract

Corrosion of metals has been a widespread issue in industries for centuries. The use of corrosion inhibitors in rust preventative fluids are commonly employed to provide the temporary corrosion protection to metals. The aim of this review is to summarize the rust inhibition properties, inhibition mechanism, chemistry and development of corrosion inhibitors for rust preventative fluids. Some suggestions for further research on corrosion inhibitors have also been discussed.

Introduction

Corrosion is the degradation of a material’s properties by chemical and/or electrochemical reaction with the environment, and in most cases it means the electrochemical oxidation of metal. The study of National Association of Corrosion Engineers (NACE) estimated that the global cost of corrosion to be $ 2.5 trillion annually, equivalent to about 3.4% of the global Gross Domestic Product (GDP) [1]. It also found that implementing corrosion prevention best practices can save 15–۳۵% of the cost of damage, that is $ 375–۸۷۵ billion. Among the various methods available to prevent corrosion of metals, rust preventative fluids are extensively used to provide temporary corrosion protection during manufacturing processes, storage and shipment. Rust preventative fluids are prepared by mixing corrosion inhibitors, film-forming agents and other additives into a base fluid, and it can be classified as solvent-based, oil-based and water-based rust preventatives according to the types of base fluid [2]. It is definite that corrosion inhibitors are critical for them to achieving high performance. Inorganic and organic inhibitors are the two main types of corrosion inhibitors. Inorganic inhibitors, such as nitrite, nitrate, chromate, dichromate, phosphate, are widely used in different base fluids and for various metals [3]. On the other hand, organic inhibitors are the compounds containing one or more polar groups (with O, N, P, S atoms, and π electrons), which are effective to prevent corrosion via adsorption on the metal surface [4–۶]. Since the polar groups are usually regarded as the reaction centers for the adsorption process, the strength of adsorption is strongly dependent on the electron density and polarizability of the polar groups [7]. Accordingly, organic inhibitors include sulfonates, alcohols, ethers, amines, amides, amine salts, carboxylates, heterocyclic nitrogen compounds, phosphates, polymers, natural products, and others in consideration of polar groups nature. The present article reviews the mechanism and development of corrosion inhibitors for rust preventative fluids.