Inhibition of Corrosion of Carbon Steel in Aqueous Medium using Naval Leaf Extract

Abstract

Corrosion is a natural process generally known as rust, an unwanted phenomenon, which spoils the lustre and beauty of objects and shortens their life. The use of organic inhibitors is one of the most practical methods for protection against corrosion of metals and their alloys. In aqueous solutions, the inhibitory action of organic inhibitors is due to their physical (electrostatic) adsorption onto the metal surface, depending on the charge of the metal surface, the electronic structure of organic inhibitor and the nature of the medium. The present study is carried out to discuss the inhibitive effect of an aqueous extract of naval leaves on the corrosion of carbon steel in dam water using weight loss method, electrochemical studies and surface analysis techniques like Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM). Results of weight loss method indicated inhibition efficiency (IE) increased with increasing inhibitor concentration to a particular extend and then it decreases. Polarization study reveals that the inhibitor system controls the cathodic reaction predominantly. AC impedance spectra reveal that a protective film is formed on the metal surface. The above results have been supported by surface morphology study using Scanning electron microscopy carried out on the carbon steel samples in the absence and presence of inhibitor.