Inhibition of aluminum corrosion in acid solution by mono- and bis-azo naphthylamine dyes. Part 1

Abstract

The effect of a series of mono-and bis-azo dyes derived from dihydroxynaphthalene on the dissolution of aluminum in 2 M HCl solutions was studied using weight loss, thermometry and galvanostatic polarization techniques. The inhibition efficiency was found to increase with increasing concentration of inhibitor to reach 97.86 % for 1×10-4 M. The inhibition mechanism is discussed on the basis of adsorption of inhibitor molecules on the metal surface. The inhibitors were adsorbed on the surface according to the Temkin adsorption isotherm. The effect of temperature on the corrosion inhibition of Al was studied and thermodynamic functions for the dissolution and adsorption processes in the absence and in the presence of the azo dyes were computed and discussed. The results obtained from the chemical and electrochemical measurements are in good agreement. Naphthylamineazo dye / Aluminum / Inhibitors / Weight loss / Thermometry / Polarization