Inhibition of Aluminum Corrosion in Hydrochloric Acid by n-, Di-n- and Tri-n-Butylamines

Abstract

Abstract Weight losses of aluminum in hydrochloric acid are diminished in the ranges 16–75 for n-; 40–90 for di-n~ and 50–98percent for tri-n-butylamine. Inhibitor efficiency increases with acid concentration up to 1.25 or 1.5 N, depending on the inhibitor and is practically constant thereafter. Efficiency increases with increased inhibitor concentration up to a certain value, then remains constant. Optimum inhibitor concentration depends on acid concentration and immersion period. Experimental results indicate corrosion of pure aluminum in hydrochloric acid solutions is essentially under cathodic control and inhibition by amines is by adsorption on cathodic areas. A similar mechanism is indicated for aluminum alloyed with manganese.