EFFECT OF CYANINE DYE SOLVENT INTERACTION ON THE ELECTROCHEMICAL CORROSION BEHAVIOR OF LOW-CARBON STEEL IN ACID-MEDIUM

The effect of the solvent used in the preliminary treatment with 1-eth yl-2(2'-hydroxystyryl)quinolinium cyanine dye solution on the electroc hemical corrosion behaviour of low-carbon steel in HCl solution as the corrosive medium has been studied. Weight loss measurements, anodic p otentiostatic polarization curves and the cathodic current values show ed that cyanine dye in protic solvents (isobutanol, isopropanol, n-but anol, water and methanol) gives a more inhibitive effect than when dis solved in aprotic ones (dimethylformate, dimethylsulphoxide, 2-butanon e, acetone and dioxane). The relative permittivities of the different solvents are not the main factor affecting the inhibitive action. It w as found that in the case of protic solvents, isobutanol gives a highe r inhibitive action and methanol gives a lower one; in the case of a p rotic so Ive nts, N,N'-dimethylformamide gives the higher inhibitive e ffect. This behaviour was confirmed by the polarization studies and th e values of the cathodic protective currents.