Investigation of some new triazole derivatives for inhibiting the acid corrosion of C1018 carbon steel: Correlation of electrochemical studies with quantum chemical calculations

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Iron and alloys of iron are commonly used in industries for various purposes. Despite their toughness, they are prone to corrosion. A common way to protect metallic components from corrosion is the use of pyridine inhibitors. Hence, two new triazole derivatives, ethyl{[5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetate (EPT) and 2-({[5-(pyridin-4-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}methyl)-1H-benzimidazole (PTB) have been synthesised and the formation of compounds were confirmed by spectral data. The inhibition efficacy of both the inhibitors on C1018 metal in 1 M HCl were examined by electrochemical techniques. The results proved the anticorrosive ability of EPT and PTB with inhibition efficiency of 92% and 94%, respectively. Meanwhile, current density decreased from 1330 µA/cm2 to 106 µA/cm2 for EPT and 79.5 µA/cm2 for PTB with an increase in inhibitor concentration. Further, both of the triazole derivatives behaved as mixed type inhibitors through the Langmuir adsorption mechanism. Surface morphological analysis gave further proof for the higher adsorbing ability of these triazole derivatives on the metallic surface. The above experimental investigations were validated by performing quantum chemical calculations. The results of theoretical methods indicated the effectiveness of EPT and PTB for protecting the metal from acid corrosion.