WL, I-E and EIS Studies on the Corrosion Behaviour of Mild Steel by 7-substituted 3-methylquinoxalin-2(1H)-ones and thiones in Hydrochloric Acid Medium
Year: 2012
Type: article
Abstract: The present study examines the use of some 7-R-3-methylquinoxalin-2(1H)-ones and thiones, namely 3-methylquinoxalin-2(1H)-one (Q=O), 3-methylquinoxalin-2(1H)-thione (Q=S), 7-chloro-3- methylquinoxalin-2(1H)-one (Cl-Q=O) and 7-chloro-3-methylquinoxalin-2(1H)-thione (Cl-Q=S) for corrosion and dissolution protection of mild steel in 1 M HCl. The inhibiting efficiency of the different inhibitors under study is evaluated by means of weight loss and electrochemical techniques (potentiodynamic curves and impedance measurements). The experimental results reveal that Q=S > Cl-Q=S > Q=O > Cl-Q=O. The variation in inhibiting efficiency mainly depends on the type and nature of the chlorine group and the substitution of an atom of oxygen by a sulphur atom. Polarization curves exhibit that these quinoxaline derivatives are predominately cathodic type inhibitors and mixedtype in the case of Q=S in molar hydrochloric acid. The inhibiting efficiency increases with the quinoxaline derivatives and reaches the maximum value of ca. 90 % in the case of Q=S at 10-3 M. The results obtained from weight loss and electrochemical studies are in reasonable good agreement and follow the same trend. The adsorption of quinoxaline derivatives on the mild steel obeys to the Langmuir isotherm model.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,670
OpenAlex ID: W2606595607