Corrosion study of Al–Fe (20 wt-%) alloy in artificial sea water with NaOH additions

The corrosion behaviour of the Al-Fe (20wt-%) alloy was investigated by electrochemical methods in an artificial sea water solution at various alkaline pH values adjusted by a NaOH solution. The electrochemical results showed lower current density values at a temperature of 23 degrees C, varying from 0.008 to 0.873mA/cm(2). The potentiodynamic polarisation results suggest the formation of a sensitive layer, which decreases with increasing pH. EIS results showed a corrosion mechanism control governing by diffusion of the solution ions across the permeable scale. SEM characterisation showed a scale formation composed of hydroxides as the main corrosion products; this was associated with increases in both the pH and the immersion time.