Inhibitory action of non toxic compounds on the corrosion behaviour of 316 austenitic stainless steel in hydrochloric acid solution: comparison of chitosan and cyclodextrin

Abstract

The inhibitory action of two non toxic organic compounds, chitosan and hydroxypropyl-beta-cyclodextrin (HP-β-CD), against the corrosion of 316 austenitic stainless steel in acidic chloride solutions was studied. Weight loss and electrochemical tests show that the inhibitory action increases with concentration of the organics, though the effect is greater with chitosan than with HP-β-CD for a given concentration. These compounds act as anodic inhibitors (by forming an adsorbing film on the metal surface and blocking the active corrosion sites), whereas the cathodic half-reaction is not significantly affected. The highest inhibition efficiency attained in 0.1 M HCl solution was 76% by using chitosan.