Investigation of some Schiff bases as acidic corrosion of alloy AA3102

The inhibiting effect of some Schiff bases on the corrosion of AA3102 aluminium in 0.1 M HCl has been studied by means of the hydrogen evolution and electrochemical impedance spectroscopy. The Schiff bases 2-hydroxyacetophenone-etansulphonylhydrazone, Salicylaldehyde-etansulphonylhydrazone, 5-bromosalicylal-dehyde-etansulphonylhydrazone and 5-chlorosalicylaldehyde-etansulphonylhydrazone were synthesized from salicylaldehyde and the corresponding amine. The hydrogen evolution tests showed that the corrosion resistance was greatly enhanced in presence of inhibitors. These results were confirmed by the impedance measurements where it was observed that the effect of inhibitor addition appears by an increase in the resistance and by a decrease in the capacity of interface. It is suggested that their effects depend on their concentration and the molecular structures. The maximum inhibition efficiencies were obtained for the 5-bromosalicylaldehydetansulphonylhydrazon and 5-chlorosalicylalde-hyde-etansulphonylhydrazone by both methods. (C) 2004 Elsevier B.V. All rights reserved.