Inhibition of copper corrosion by the essential oil of Allium sativum in 0.5M H 2 SO 4 solutions
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Inhibition of copper corrosion by the essential oil of Allium sativum in 0.5M H2SO4 solutions K. Mzioud1 · A. Habsaoui1 · M. Ouakki2 · M. Galai1 · S. El Fartah1 · M. Ebn Touhami1 Received: 10 April 2020 / Accepted: 20 August 2020 © Springer Nature Switzerland AG 2020
Abstract Materials in general and copper in particular, have a wide variety of industrial applications. However, they can easily corrode in aggressive environments. The anticorrosive action of copper by the essential oil of Allium sativum in a 0.5M H2SO4 solutions has been studied using electrochemical techniques: electrochemical impedance spectroscopy and potentiodynamic polarization. The polarization curves indicate that the studied oil acts as a cathodic inhibitor retarding the cathodic reaction. An appropriate electrical equivalent circuit model was used to calculate the electrochemical impedance parameters. The results obtained showed that the inhibition efficiency depends on the inhibitor concentration and the temperature. This efficiency reached 97% at a concentration of 1.0 g/L. Some thermodynamic parameters for activation process and metal dissolution such as activation energy (Ea) activation entropy (ΔSa) and the activation enthalpy (ΔHa) were also calculated and discussed. Keywords Corrosion · Inhibition · Copper · Garlic · Adsorption · Sulphuric acid
1 Introduction Due to its excellent thermal conductivity, electrical conductivity, ductility, and good workability, copper is widely used in various fields, such as machinery manufacturing, power transmission, cooling and heating systems, military industry, and so on [1–4]. In order to obtain a shiny final copper surface, which is required in some applications, or to remove scale deposits that reduce the heating efficiency of some copper-based equipment, a sulphuric acid solution is frequently used to remove any undesirable products formed at the surface (oxidation films, incrustations, scale etc.) [3–5]. Therefore, corrosion of copper can be caused during this chemical treatment after the scale or oxides have been removed, which implies the dissolution of the metal and the consumption of the acid used. This also implies important economic losses for
the industrialists [6, 7]. Corrosion phenomenon can be reduced by the use of inhibitors. According to the literature, several studies have been carried out in this field for hundreds of years [8–10]. In 1860 Great Britain announced the discovery of the world’s first corrosion inhibitor. Since this discovery, a lot of work has been done to find and develop different types of organic and inorganic inhibitors [11]. Previous studies have found that the presence of heteroatom’s such as nitrogen, sulphur and phosphorus in the molecular structure of these inhibitors improves their inhibition effectiveness. Therefore, they can establish a coordination bonds between the free doublets of these heteroatom’s and the empty d-orbital’s of transition metals, which indicate the formation of an effective barrier film that isolates the metal substrate from t
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