We investigated the mechanical and electrochemical properties of aluminum alloys. Aluminum alloys do not corrode due to the formation of an anti-corrosive passive film, such as Al2O3 or Al2O3·3H2O, which resists corrosion in neutral solutions. In seawater, however, Cl. ions destroy this passive film. The current density in the first passivity range during the application of anodic protection had a similar value as that for concentration polarization by dissolved oxygen during the application of cathodic protection. The current density in the first passivity range had the lowest value overall. The lowest current densities in the potentiostatic and galvanostatic tests occurred at potentials of .1.4 to .0.7 V and .0.9 to .0.7 V, respectively.