%0 Journal Article
%T Electrochemical and Surface Morphological Studies of Carbon Steel Corrosion by a Novel Polynuclear Schiff Base in HCl Solution
%A K. S. Shaju
%A K. Joby Thomas
%A Vinod P. Raphael
%A Aby Paul
%J ISRN Electrochemistry
%D 2013
%R 10.1155/2013/820548
%X The corrosion inhibition efficiency of a potential polynuclear Schiff base, (s)-2-(anthracene-9 (10H)-ylidene amino)-5-guanidinopentanoic acid (A9Y5GPA), on carbon steel (CS) in 1£¿M hydrochloric acid solution has been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization studies. The corrosion inhibition efficiencies of parent amine [(s)-2-amino-5-guanidinopentanoic acid] and parent ketone (anthracene-9 (10H)-one) on carbon steel in 1.0£¿M hydrochloric acid solution have also been investigated using weight loss studies. The electrochemical and weight loss data established that the inhibition efficiency on CS increases with the increase in the concentration of inhibitor, A9Y5GPA. The adsorption of A9Y5GPA obeys the Langmuir adsorption isotherm. Thermodynamic parameters ( , ) were calculated using the adsorption isotherm. Activation parameters of the corrosion process ( , and ) were also calculated from the corrosion rates obtained from temperature studies. Tafel plot analysis revealed that A9Y5GPA acts as a mixed-type inhibitor. A probable inhibition mechanism was also proposed. Surface morphology of the carbon steel specimens in the presence and absence of the inhibitor was evaluated by SEM analysis. 1. Introduction The use of hydrochloric acid in metal industries for acid pickling, descaling, and cleaning process is the major reason for the increase in the dissolution rate of carbon steel. The use of certain organic compounds as inhibitors is the most practical method to prevent corrosion of the carbon steel (CS) in acidic media [1¨C3]. Compounds with -bonds generally exhibit good inhibitive properties due to interaction of -orbital with the metal surface [4]. Schiff bases are organic molecules possessing azomethine linkage and many of them act as effective potential corrosion inhibitors [5¨C8]. Increasing efforts have been made to study the corrosion behavior of metals and mechanism of inhibition during the past decade mainly through electrochemical investigations [9¨C11]. The present investigation was undertaken to examine the corrosion inhibition behavior of a novel polynuclear Schiff base (A9Y5GPA) derived from anthracene-9 (10H)-one and (s)-2-amino-5-guanidinopentanoic acid in 1£¿M£¿HCl solution on CS at different temperatures. The study was performed by weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization analysis. 2. Experimental 2.1. Inhibitor Polynuclear Schiff base (A9Y5GPA) was obtained by the condensation of equimolar mixture
%U http://www.hindawi.com/journals/isrn.electrochemistry/2013/820548/