Influence of Hydrostatic Pressure and Salt Concentration on Aluminum Corrosion in NaCl Solutions Available to Purchase

The effect of hydrostatic pressure on the corrosion kinetics of aluminum in NaCl solutions at different concentrations (from 5 × 10⁻² to 1 M/L) at pH 8.2, 20 C, and with a dissolved oxygen concentration near saturation (~ 5 ppm) has been examined. The pressure values were 1,10, 100, and 300 atm. It has been found that the increase in hydrostatic pressure increases the susceptibility to pitting and decreases the passivation range between E_corr and E_p as a result of the slighter thickness and the greater number of defects in the oxidation layer. The decrease in thickness with increasing pressure was explained with both the different hydration degree of the ions and the change of the interaction kinetics of Cl⁻ ions with the aluminum surface.