Aromatic Triazoles as Corrosion Inhibitors for Mild Steel in Acidic Environments

3-hydroxyphenyl-4-phenyl-5-mercapto-1,2,4,triazole (HPMT); 3-aminophenyl-4-phenyl-5-mercapto-1,2,4,triazole (APMT); 3,4-diphenyl-5-mercapto-1,2,4-triazole (DPMT); and 3-cinnamyl-4-phenyl-5-mercapto-1,2,4,triazole (CPMT) were synthesized in the laboratory, and their influence on the inhibition of corrosion of mild steel in 1 N hydrochloric acid (HCl) and 1 N sulfuric acid (H2SO4) was investigated by weight loss and potentiodynamic polarization techniques. The inhibition efficiency of these compounds was found to vary with concentration, temperature, and immersion time. Good inhibition efficiency was evidenced in both acid solutions. The adsorption of these compounds on the steel surface for both acids was found to obey Temkin’s adsorption isotherm. The potentiodynamic polarization data showed that the compounds studied were filming (adsorption) inhibitors.