Investigation on corrosion inhibition and adsorption mechanism of azomethine derivatives at mild steel/0.5 M H2SO4 solution interface: Gravimetric, electrochemical, SEM and EDX studies

The inhibition performance of five azomethine derivatives such as: 1-(4-Methyloxy phenylimino)-1(phenylhydrazono)-propan-2-one (SB1), 1-(4-Methylphenylimino)-1-(phenylhydrazono) propan-2-one (SB2), 1(phenylimino)-1(phenylhydrazono)-propan-2-one (SB3), 1-(4-Bromo phenylimino)-1(phenylhydrazono)-propan2-one (SB4) and 1-(4-Chlorophenylimino)-1(phenylhydrazono) -propan-2-on (SB5) as corrosion inhibitors for mild steel in sulfuric acid 0.5 M were investigated using different methods. All experimental results demonstrate that these compounds are eficients inhibitors. The inhibition efficiencies (IE) increase with inhibitors concentration. At 7.5 x 10-5 M, the IE was 97.27%, 96.31%, 94.23%, 93.19 and 91.64% for SB1, SB2, SB3, SB4 and SB5, respectively. The potentiodynamic polarization results indicated that all the studied inhibitors act as mixed type. The adsorption process on mild steel surface obeyed Langmuir isotherm. The associated activation parameters and thermodynamic have been calculated and discussed. The adsorbed film formed on the metal surface was characterized by SEM and EDX.