Corrosion is defined as the deterioration usually a metal by its interaction, with highly reactive elements such as oxygen (air), halogens, oxides of sulphur, etc., in the surrounding moist environment. In general, corrosion leads to the formation of oxides, hydroxides, etc., at the metal’s surface, better known as rust, in colors specific to the substrate metal. Corrosion, otherwise, simply known as rust, is supposed to be one of the biggest factors for the degradation of metallic materials, specifically, iron, used in millions of tons, annually, in almost all buildings, railway wagons and tracks, surface and subsurface marine vehicles/equipment, agriculture equipment, and implements, weapon systems, etc. The corrosion process is more pronounced in the marine environment due to biofouling. The latter is caused due to adherence of several kinds of microorganisms found in the marine environment. Corrosion of articles in the marine environment caused by biofouling results in a 10% increase in the fuel consumption in motorized sea vehicles, in addition to threatening the reliability, service life, and environmental adaptability thereby resulting in huge economic losses.The annual global cost of damage caused by corrosion is estimated at around $ 2 trillion USD. It is believed that 25 - 30% could be prevented with proper corrosion protection. Hence, corrosion prevention in a specific environment is a big challenging task for a material scientist. There are several methods of corrosion prevention that are either based on electrochemical principles or separating the metal from its corrosion-inducing environment. In certain cases, it may be possible to adjust the surrounding environment in order to make it less corrosive. Choosing the most effective method is not always simple and easy. This choice is partly governed by the ambient environmental conditions and economic considerations.

Generally, corrosion prevention technologies use one or more of the following approaches:

​

• Use non-corrosive metals and alloys such as stainless steel or aluminum

• Make sure the metal surface stays clean and dry

• Use a coating or barrier product such as grease, oil, paint, or carbon fiber coating

• Lay a layer of backfill, for example, limestone, with underground piping

• Use a sacrificial anode to provide a cathodic protection system, etc.

Out of many such measures use of coatings or barrier products has proven as most cost-effective. The importance of coating could be emphasized because of its multifunctional characteristics such as cathodic protection (sacrificial), modification of environment (barrier effects and inhibition), and materials selection from a broad range of conventional and advanced materials. Such coatings are comprised either of other metals more resistant to oxidation than the base metal e.g., coating of chromium, zinc, tin, or chromium on articles made out of iron or a  hybrid of inorganic and organic (OIH) materials. Over the past few decades, technological development has led to the production of a large variety of coatings and materials that have an efficient barrier effect preventing corrosion, namely inorganic coatings, paints, and other surface treatments. Among them, chromate and similar hexavalent chromium compounds dispersed in epoxy, polyurethane, or alkyd binder reins are effective substances as inhibitors and are usually incorporated in anticorrosive pre-treatments of a wide range of metals and alloys. The toxicity of chromium ions has put restrictions on many countries on their large-scale use in anti-corrosion applications.