Inhibition Effects of N,N‐Dimethylalkylamines and Octanethiol on Iron Corrosion in Anhydrous Acetonitrile Solution Containing FeCl3

Abstract

Polarization and impedance measurements were carried out on an iron electrode in an anhydrous acetonitrile solution of and containing organic corrosion inhibitors. The inhibitors investigated were N,N‐dimethylalkylamines and octanethiol . These compounds suppressed both cathodic and anodic processes of iron corrosion in the acetonitrile solution. The double‐layer capacitances obtained from impedance data for the electrode inhibited with were markedly lower in the potential region of the cathodic polarization curve than those for the uninhibited electrode. Ultraviolet and visible spectra of the acetonitrile solution containing revealed the formation of a complex cation with , and joint adsorption of the complex cation with on the iron surface was substantiated by X‐ray photoelectron spectroscopy of the surface treated with the solution. A surface thiolate of was formed by its chemisorption on the iron surface, resulting in a decrease in the double‐layer capacitance and the cathodic and anodic current densities, respectively. © 2000 The Electrochemical Society. All rights reserved.