THE EFFECT OF SAME ETHOXYLATED FATTY-ACIDS ON CORROSION OF ALUMINUM IN HYDROCHLORIC-ACID SOLUTIONS

The inhibitive effect of some ethoxylated fatty acids St(EO)(80), OL(E O)(20), OL(EO)(40) and OL(EO)(80) on the corrosion of two types of alu minium. Al(1) and Al(2). has been studied in 1 M hydrochloric acid sol ution by weight loss method. The effect of inhibitor concentration. te mperature and time of immersion have been investigated. The inhibitive effect of these fatty acids is due to their adsorption on aluminium s urfaces. The inhibitive efficiency depends on both the type and concen tration of additives. Increasing the ethylene oxide units in the molec ules and the presence of the double bond in oleate structure will enha nce the inhibition efficiency. The activation energy and the thermodyn amic parameters for the corrosion process in the absence and presence of the inhibitors were determined. By fitting the corrosion datal it i s found that the results are with Langmiur, Frumkia, Flory-Huggins iso therm and the kinetic thermodynamic model. (C) 1998 Elsevier Science S .A.