The effect of same ethoxylated fatty acids on corrosion of aluminium in hydrochloric acid solutions

The inhibitive effect of some ethoxylated fatty acids St(EO)(80), OL(EO)(20), OL(EO)(40) and OL(EO)(80) on the corrosion of two types of aluminium. Al(1) and Al(2). has been studied in 1 M hydrochloric acid solution by weight loss method. The effect of inhibitor concentration. temperature and time of immersion have been investigated. The inhibitive effect of these fatty acids is due to their adsorption on aluminium surfaces. The inhibitive efficiency depends on both the type and concentration of additives. Increasing the ethylene oxide units in the molecules and the presence of the double bond in oleate structure will enhance the inhibition efficiency. The activation energy and the thermodynamic parameters for the corrosion process in the absence and presence of the inhibitors were determined. By fitting the corrosion datal it is found that the results are with Langmiur, Frumkia, Flory-Huggins isotherm and the kinetic thermodynamic model. (C) 1998 Elsevier Science S.A.