Effect of halides ions on H2 production during aluminum corrosion in formic acid and using some inorganic inhibitors to control hydrogen evolution

This study reports on the systematic assessment of H-2 production by corrosion of aluminum in formic acid solution in the absence and presence of halide ions and some inorganic inhibitors using hydrogen evolution measurements and complemented by scan electron microscope (SEM) and energy dispersive X-ray (EDX). It is shown that the rate of H-2 production and in turn the dissolution of aluminum increases with increasing acid concentration and solution temperature. Addition of halides ions enhances the active dissolution of aluminum and tends to breakdown the passive film and increases H-2 production. The addition of tungstate, molybdate and nitrite anions to (1.0 M formic acid + 0.2 M Cl-) solution retard the rate of H-2 production, where the H-2 production process decreases in the following in the order: tungstate > molybdate > nitrite. (C) 2013 Elsevier B.V. All rights reserved.