Modeling cathodic shielding of sacrificial anode cathodic protection systems in seawater

摘要

Two kinds of cathodic shielding phenomena of the sacrificial anode cathodic protection systems, which are caused by a metal barrier, were investigated by numerical simulations and experiments in this paper. The results show that if the cathode current is completely shielded by the barrier, one side of the barrier would act as the anode leading to the occurrence of serious corrosion, while the protected components and the other side of the barrier would act as cathode being protected. However, if the cathode current is only partially shielded, both the metal components and the barrier would act as cathodes. Furthermore, this non-full shielding effect of the barrier would be weakening by decreasing the mass transfer resistance between the sacrificial anode and the cathodically protected component.