Collect. Czech. Chem. Commun. 1994, 59, 539-548

The Effect of the Molecular Structure of Cyanine Dye on the Corrosion of Low-Carbon Steel in Hydrochloric Acid Solution

Mohamed Th. Makhlouf

Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt


The effect of two different cyanine dyes 2-(2-hydroxystyryl)quinolinium-1-ethyl iodide (I) and 4-(2-hydroxystyryl)quinolinium-1-ethyl iodide (II) on the electrochemical corrosion behaviour of low-carbon steel (0.05% C, 0.04% Si, 0.023% S, 0.004% Cu) in HCl solution has been studied. Weight loss measurements, galvanostatic polarization curves, open-circuit potential variation of steel electrode with time and the cathodic protective current values show that the investigated cyanine dyes have an anticorrosive character. The inhibition effect depends mainly on the structure of the studied dye molecules, and is more pronounced in case of pretreated carbon steel with the dye solution before immersion in the corrosion medium than that obtained by addition of the dye to the corrosive medium.