Abstract
The effect of some transition and heavy metal cations on the dissolution of aluminum has been investigated in neutral and acid Cl− solutions by potentiodynamic polarization, gravimetric and thermometric measurements, and surface examination by SEM. At low cation concentrations, deposition of the metals corresponding to these cations on aluminum surface by displacement consumes the electrons otherwise available for the cathodic reaction, and corrosion inhibition is observed. This is, however, counteracted by the acceleration due to galvanic coupling between the deposited metal and aluminum at higher cation concentrations. Deposition of metals on aluminum by displacement is not uniform. Pitting corrosion of aluminum increases considerably neighboring to the deposited metal segregates. Inhibition of the accelerating effect of cations and Cl− by 
, benzotriazole, 
, 
, 
, benzoate, and sulfanilic acid decreased in the given order. Binary mixtures of 
and 
acid showed effective synergetic inhibition which stopped the dissolution of aluminum. 
inhibit the aggressive effect of cations by hindering the displacement process through the repair of the oxide film defects together with strong adsorption on its surface.