Read the passage below:
To safeguard steel vessel hulls from galvanic deterioration in saltwater environments, marine technicians attach sacrificial zinc anodes along the submerged hull surface. Because zinc possesses a lower electrochemical potential than structural steel, the seawater electrolyte causes the zinc to corrode preferentially. As the zinc oxidizes and sheds electrons, it maintains a protective electrical current that shields the surrounding ferrous metal from rusting. However, if technicians mistakenly apply marine bottom paint over these anodes during scheduled maintenance, the coating insulates the zinc from the surrounding seawater, completely halting the galvanic current and accelerating hull degradation.
According to the passage, why does painting over sacrificial anodes harm a vessel's hull?
- AIt causes structural steel to corrode preferentially while zinc sheds electrons directly into the paint layer.
- BIt elevates the electrochemical potential of the ferrous metal above that of the surrounding saltwater.
- It creates an insulating barrier that prevents direct contact with seawater, disabling the galvanic protective circuit.Cevap
- DIt traps corrosive moisture underneath the coating, causing rapid blister cracking across the keel plates.