Corrosion of Copper in 0.1 M Hydrochloric Acid Solution with Benzotriazole as Corrosion Inhibitor
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HYSICOCHEMICAL PROBLEMS OF MATERIALS PROTECTION
Corrosion of Copper in 0.1 M Hydrochloric Acid Solution with Benzotriazole as Corrosion Inhibitor M. Aminia, M. Toorania, and A. Sabour Rouhaghdama, * a
Department of Materials Engineering, Tarbiat Modares University, Tehran, Iran *e-mail: [email protected] Received March 9, 2018; revised March 15, 2020; accepted March 17, 2020
Abstract—Corrosion inhibition properties of benzotriazole were studied in 0.1 M hydrochloric acid solution for copper samples with different roughness levels using open-circuit potential, potentiodynamic polarization, electrochemical impedance, and weight loss measurements. According to the results, inhibition properties were improved because of an increase in surface roughness leading to an increase in inhibition efficiency (up to 99 and 91% for the rough and smooth surfaces, respectively). Adsorption of benzotriazole on copper surfaces follows Langmuir isotherm. Due to roughening, the adsorption free energy changed from ‒25.9 kJ mol–1 for the polished samples to –27.6 kJ mol–1 for the rough sample. Adsorption of the inhibitor on both surfaces was mainly physisorption. Adsorption entropy values for polished and shot-peened samples were 11.4 and 13 J mol–1 K–1, respectively. All data obtained from weight loss, Tafel polarization, and EIS tests were in good agreement. FTIR test, showed a peak between 740 and 745 cm–1 that is associated with C– H bonds. The intensity of peak was higher in the case of shot-peened samples. Keywords: corrosion, copper, benzotriazole, roughness DOI: 10.1134/S2070205120040048
1. INTRODUCTION Copper and its alloys are well-known for their favorable properties such as conductivity, workability, and resistance which make them suitable for a wide range of applications [1, 2]. Although copper is resistant in the atmosphere and many chemical media [3], it is sensitive to corrosion in hydrochloric acid solutions that are used for removing scales and other corrosion products from industrial parts [4–6]. Copper may be exposed to acid and dissolves in the removing process. An essential method for the protection of copper against corrosion is the use of organic corrosion inhibitors [7]. Benzotriazole (BTA) is widely used triazole-type corrosion inhibitor [2, 8, 9]. Inhibition behavior of BTA on copper’s corrosion has been studied in different types of media such as solutions containing chloride ions, fairly neutral and strong acidic and alkaline solutions and industrial atmosphere [10]. It should be noted that BTA’s performance in strong acidic or alkaline solutions is as weak as it is in the media with aggressive ions. Benzotriazole, as an effective inhibitor for copper and its alloys, is an organic compound made of benzene and triazole loops as some heterocyclic organic compounds. An important application of BTA is protection of copper and its alloys under immersion conditions by preventing the occurrence of undesired processes on the surface. BTA prevents
color change of copper surfaces under immersion conditions. Althoug
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