%0 Journal Article
%T 3-Formylindole-4-aminobenzoic Acid: A Potential Corrosion Inhibitor for Mild Steel and Copper in Hydrochloric Acid Media
%A Aby Paul
%A Joby Thomas K.
%A Vinod P. Raphael
%A K. S. Shaju
%J ISRN Corrosion
%D 2012
%R 10.5402/2012/842836
%X The corrosion inhibition efficiencies of Schiff base 3-formylindole-4-aminobenzoic acid (3FI4ABA) on mild steel (MS) and copper in 1.0£¿M HCl solution have been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies. The results show that inhibition efficiencies on both metals increase with increasing the concentration of the inhibitor. 3FI4ABA exhibited comparatively good inhibition towards mild steel in HCl medium even at low concentrations. The adsorption of inhibitor on the surfaces of the corroding metal mild steel and copper obeys the Langmuir isotherm. Polarization studies revealed that 3FI4ABA acts as a mixed-type inhibitor. Thermodynamic parameters ( , ) were calculated using the Langmuir adsorption isotherm. 1. Introduction Schiff bases are organic molecules possessing azomethine linkage (C=N) and have innumerable advantages, right from pharmaceutical applications to the corrosion inhibitions, in the various fields of science. The heteroatoms present in these molecules are of key importance and are responsible for the corrosion inhibition in acidic media on the metal surface [1¨C3]. Some recently reported Schiff bases showed effective inhibition for mild steel (MS), aluminum, copper, and zinc in acidic media [4¨C11]. The study on MS and copper corrosion has become much important particularly in industrial and academic fields. Enormous use of hydrochloric acid for acid pickling, descaling, and cleaning process of mild steel surface are the major reasons for the corrosion problems in the world. Increasing efforts have been made to study the corrosion behavior of metals and mechanism of inhibition during the past decade mainly through electrochemical investigations [8, 9]. Limited work has been reported for the corrosion inhibition of compounds derived from 3-formylindole in acid media. The present investigation was undertaken to examine the corrosion inhibition capacity and mechanism of inhibition of a novel heterocyclic Schiff base (3FI4ABA) molecules derived from 3-formylindole and 4-aminobenzoic acid in 1£¿M£¿HCl solution on MS and Copper. The study was performed using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization analysis. 2. Experimental 2.1. Inhibitor Heterocyclic Schiff base was obtained by the condensation of equimolar mixture of 3-formylindole and 4-amino benzoic acid in ethanol. The reaction mixture was refluxed for 2 hours, evaporated and cooled in ice bath to obtain yellow coloured compound. Figure 1 shows
%U http://www.hindawi.com/journals/isrn.corrosion/2012/842836/