Cationic surfactant as corrosion inhibitor for aluminum in acidic and basic solutions

Purpose - To investigate the inhibiting effect of the cationic surfactant cetyl trimethylammonium chloride (CTAC) on aluminum (Al). Design/methodology/approach - Pure aluminum rods were immersed in hydrochloric acid (HCl) and sodium hydroxide (NaOH) solutions for weight-loss tests and potentiostatic polarization measurements. Findings - The inhibition action depends on the concentration of the inhibitor, the concentration of the corrosive media, and the temperature. The inhibition efficiency in NaOH was higher than that in HCl solutions. In both acidic and basic media, the increase in temperature resulted in a decrease of the inhibition efficiency and a decrease in the degree of surface coverage. The results were indicative of increased aluminum dissolution with increasing temperature. It was found that adsorption of CTAC on the aluminum surface follows Temkin's isotherm in HCl and Langmuir's isotherm in NaOH. Originality/value - Clarifies the effects of concentration and temperature on the inhibition efficiency of a cationic surfactant on aluminum.