Anticorrosive efficiency of novel 1,4-benzothiazinone derivative for mild steel in phosphoric acid solution

• A. El-khlifi¹, M. Saadouni², R. Ijoub¹, Y. El Aoufir^3,4, S. Boukhriss², B. Hammouti⁵ and M. Ouhssine¹

¹ Laboratoire de Biotechnologie, Environnement et Qualité, Faculté des Sciences, Université Ibn Tofaïl, 14000 Kénitra, Morocco
² Laboratory of Organic, Organometallic and Theoretical Chemistry, Faculty of Science, Ibn Tofaïl University, 14000 Kenitra, Morocco
³ Laboratory of Separation Processes, Faculty of Sciences, University Ibn Tofail, Kénitra, Morocco
⁴ Laboratory of Nanotechnology, Materials & Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
⁵ Laboratory of Analytical Chemistry, Materials, and Environment (LC2AME), Faculty of Sciences, University of Mohammed Premier, B.P. 717, 60000 Oujda, Morocco

Abstract: Corrosion is a big challenge and many corrosion control methods have been adopted all over the world. It can damage the materials, which are used to construct automobiles, pipeline systems, bridges and buildings, petroleum refineries, etc. Corrosion inhibitors are used as effective alternatives for the protection of metallic surfaces against corrosion. Herein, the corrosion inhibition characteristics of 2-(4-сhlorophenyl)-1,4-benzothiazin-3-one (CBT) have been studied as efficient inhibitor for corrosion control of mild steel in 2.0 M phosphoric acid solution using potentiodynamic polarization, weight loss measurements and electrochemical impedance spectroscopy (EIS) techniques. The effects of inhibitor concentration on the inhibition action were investigated. The corrosion inhibition efficiency increased with the increase of CBT concentration up to 85% obtained at 25 °C at 5 mM concentration. The adsorption of CBT on metal surface obeyed Langmuir adsorption isotherm. Adsorption isotherm study suggests that both physical and chemical adsorptions may be the type of adsorption of the inhibitor on the metal surface. Polarization measurements showed that the CBT acted as mixed inhibitor. The surface morphology of mild steel, in the absence and presence of CBT in 2.0 M phosphoric acid solution, was studied using scanning electron microscopy (SEM). The SEM analysis strongly supports the results of electrochemical measurements.

Keywords: corrosion inhibition, benzothiazine, mild steel, phosphoric acid, EIS

Int. J. Corros. Scale Inhib., 2019, 8, no. 3, 659-672 PDF (1 527 K)
doi: 10.17675/2305-6894-2019-8-3-14

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