Investigation of Synthesized Sulfonated Melamine Formaldehyde as a Novel Corrosion Inhibitor for Mild Steel in Saline Environment

A water soluble compound named sulfonated melamine formaldehyde (SMF) was synthesized and its corrosion inhibition behavior was studied for carbon steel in 3.5% NaCl solution by polarization measurements and electrochemical impedance spectroscopy (EIS). SMF was characterized with hydrogen nuclear magnetic resonance spectroscopy and then its physical properties and corrosion prevention efficiencies were investigated. The corrosion behavior of SMF was found to be dependent strongly on the electric nature of functional groups which are present in its structure. The decrease in (i (corr)) and the increase in inhibition efficiency (% IE) with increasing the SMF concentrations proves that it protects C-steel in 3.5% NaCl solution from being corroded and Nyquist diagrams indicate that increasing charge transfer resistance is associated with a decrease in the capacitance and increase in the percentage inhibition efficiency. The decrease in capacitance values could be attributed to the adsorption of the inhibitor molecules at the metal surface by increasing the concentration of inhibitor in the solution the inhibition efficiency increased and the best inhibition was obtained at 1000 ppm inhibitor concentration. The scanning electron microscope was used to investigate the surface morphology of specimens in the absence and presence of inhibitor compound.