Corrosion inhibitory effects of a new synthetic symmetrical Schiff‐base on carbon steel in acid media

Abstract

In this investigation, the inhibitory effect of a new synthesised tetra‐dentate Schiff‐base, bis‐(2‐hydroxy‐1‐naphthaldehyde) 1,6‐hexadiamine (A₁), on the corrosion of carbon steel in 1 M HCl and 0.5 M H₂SO₄ media solutions was studied using various techniques including electrochemical impedance spectroscopy polarisation curves and weight loss. The new compound was shown to be a very good inhibitor and had better behaviour in 1 M HCl than was the case in 0.5 M H₂SO₄. Potentiodynamic polarisation tests showed that this inhibitor had both cathodic and anodic action. Changes in Tafel and impedance parameters (I_corr, R_ct and C_dl) indicated that the absorbed protective film grows with increasing exposure time and concentration of inhibitor. The maximum inhibition efficiency was approximately 97 per cent and 95 per cent at 100 ppm (A₁) in 1 M HCl and 0.5 M H₂SO₄. The adsorption of this inhibitor on a carbon steel surface in both acidic media followed Langmuir adsorption isotherm behaviour.

Citation

Dadgarnezhad, A., Sheikhshoaie, I. and Baghaei, F. (2004), "Corrosion inhibitory effects of a new synthetic symmetrical Schiff‐base on carbon steel in acid media", Anti-Corrosion Methods and Materials, Vol. 51 No. 4, pp. 266-271. https://doi.org/10.1108/00035590410541337