Corrosion Inhibition Studies on Mild Steel by Tetramethyl Ammonium Bromide in Hydrochloric Acid Medium

The inhibitory effect of tetramethyl ammonium bromide (TMAB) on mild steel corrosion was investigated in the presence of hydrochloric acid (HCl) by using the electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques. The morphology of the mild steel surface was studied using scanning electron microscopy (SEM) technique, while the surface corrosion products were analyzed by Fourier transform infrared (FTIR) spectroscopy. Surface inhibition is the simplest method to protect metals and alloys from corrosion, and good inhibition efficiency leading to reduced corrosion rates was found from our studies and experimentation. Inhibition efficiency was enhanced with the rise in the concentration of TMAB in HCl solution and the direct correlation of corrosion rate with the inhibitor concentration is appropriately explained. Polarization curves displayed TMAB as an effective mixed-type inhibitor that reduced the corrosion rate of the mild steel. The nature of the corrosion attack and the phases present in the rust ascertained a significant reduction in corrosion by the addition of TMAB to 0.1 M HCl. Systematic analyses were also performed to analyze the corrosion rate in the absence of TMAB for a range of acid concentrations from 0.1 to 1.0 M.