Evaluation of Corrosion Inhibition of a Novel Class inhibitors for Mild Steel Corrosion in HCl Solution

چکیده مقاله

Corrosion inhibitors in mild steel play a fairly important role in mild steel different application. Stainless steels are designed for applications in aggressive oil field and marine environments where both corrosion resistance and mechanical properties of stainless steels would perhaps be limited [1]. Hydrochloric acid solution causes corrosion of stainless steel [2]. It is well known that corrosion never stops but its scope and severity can be lowered. However, corrosion control is an essential issue from application point of view and it has been reported that inhibitors are needed to be used which act as a barrier to reduce the aggressiveness of the environments against the pitting corrosion attack [3–5]. Organic compounds are commonly used as corrosion inhibitors to reduce the corrosion attack on stainless steel in acidic media. Besides widely used of 2-aminobenzothiazole derivatives have been demonstrated to be other promising mild steel inhibitors. In this paper, the properties of three derivatives of 2-aminobenzothiazole namely 1, 3-Benzothiazol-2-amine (BA), 6-Bromo-1, 3-benzothiazol-2-amine (6-BBA), 6-Chloro-1, 3-benzothiazol-2-amine (6-CBA) on the mild steel corrosion in 6.0 M hydrochloric acid have been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. These studies were carried out at different concentrations and temperatures. Polarization measurements indicate that the three inhibitors act as mixed type inhibitors. The adsorption of inhibitors obeys the Langmuir adsorption isotherm and the thermodynamic parameters (Ea, Kads, ΔG0 ads) were calculated and discussed. Quantum chemical calculations were performed to provide further insight into the inhibition efficiencies determined experimentally