Insights into corrosion inhibition behavior of a triazole derivative For mild steel in hydrochloric acid solution

In order to search for new molecules and use them as corrosion inhibitors of mild steel in 1M HCl, (Z) -5-methyl-4 -((3-nitrobenzylidene) amino) -2,4-dihydro-3H-1,2,4-triazole-3-thione (C10H9N5O2S) (2m), is a novel inhibitor. Its inhibitory action was studied using gravimetric measurement, electrochemical impedance spectroscopy, potentiodynamic polarization, scanning electron microscopy (SEM) and theoretical calculations. The methods cited above, reveal that (2m) is an excellent inhibitor. Its maximum inhibition efficiency reaches up to 89.74 % at 10-6M. The inhibition of corrosion is due to the adsorption of the inhibitor on the mild steel. Potentiodynamic polarization shows that (2m) acts as a mixed type inhibitor with a certain cathodic predominance. Scanning electron microscopy shows an improved morphology of the surface of mild steel in the presence of the inhibitor studied. The inhibition mechanism was explored by the potential of zero charge (Epzc) measurement at the solution/metal interface. The quantum chemical parameters were calculated using the DFT method to correlate the electron properties with the adsorption and inhibition behavior of (Z) -5-methyl-4 -((3-nitrobenzylidene) amino) -2, 4-dihydro-3H-1,2,4-triazole-3-thione. (C) 2019 Published by Elsevier Ltd.