**2. Historical background**

Corrosion can be viewed as a universal phenomenon, omnipresent and omnipotent. It is there everywhere, air, water, soil and in every environment, we encounter [7]. Known to people as rust, corrosion is an undesirable phenomenon which destroys the luster and beauty of the materials and lessens their life. Indian government spending around 3.5% Lakscrores of the nation's GDP per annum for losses of corrosion [8]. Recent studies estimate that, not only in India, other countries also rise their funds for demand of corrosion inhibitors [9].

Corrosion costs manifest in the form of premature deterioration or failure necessitating maintenance, repairs and replacement of damaged parts.. Corrosion has a vast environmental and economic impact on all the surfaces of national infrastructure like highways, bridges, buildings, chemical processing units, waste water treatment and virtually on all metallic objects in our day to day life use [10]. Other than material loss, corrosion interferes not only with environment, also affects human safety and industrial operations severely. Awareness to corrosion and adaptation of timely and appropriate control measures hold the key in the abatement of corrosion failures [11].
