Corrosion Inhibition of Aluminium in 1.0 M HCl by Zinc Phtalocyanine Sulfonate

Abstract

The inhibitive effect of sulfonated zinc phthalocyanine (ZnPcS) on the corrosion of aluminium in 1.0 M hydrochloric acid is hereby explored. Corrosion data were obtained via weight loss experiments, and ZnPcS proved to be an efficient inhibitor, with its molecules being adsorbed on the surface of the aluminium coupons. The adsorption pattern conforms to the classical Langmuir model. Corrosion rates generally decreased with ZnPcS concentration between 303 K and 323 K. However, inhibition efficiency reduced when temperature was increased from 303 K to 313 K, and then increased with further temperature increase to 323 K, which is attributed to physisorption (303 K – 313 K) and chemisorptions (323 K). It is suggested that the metal forms coordinate bonds with the electron-donating functionalities on ZnPcS at 323 K.