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The inhibitive effect of 5‐amino‐indole on the corrosion of mild steel in acidic media
Author(s) -
Düdükcü M.
Publication year - 2011
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200905524
Subject(s) - adsorption , dielectric spectroscopy , langmuir adsorption model , corrosion , polarization (electrochemistry) , electrochemistry , corrosion inhibitor , electrical impedance , langmuir , materials science , chemistry , inorganic chemistry , nuclear chemistry , metallurgy , electrode , physics , quantum mechanics
The inhibitor performance of 5‐aminoindole (5‐AI) on mild steel corrosion in 0.5 M HCl was investigated in relation to the inhibitor concentration using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization (LPR) methods. The effect of immersion time on the corrosion behavior of mild steel was also studied. The impedance data obtained were fitted and modeled using an equivalent circuit model. The results show that 5‐AI is an effective inhibitor and has an inhibition efficiency of 90% at 1 × 10 −2 M additive concentration. The adsorption behavior of 5‐AI was also investigated. For this purpose, the adsorption equilibrium constant ( K ads ), and the free energy of adsorption (Δ G ads ) were calculated and discussed. It was found that 5‐AI acts as mixed‐type inhibitor and obeys Langmuir adsorption isotherm with a free energy of adsorption of −27.71 kJ/mol.