Explain sacrificial protection as a method of preventing corrosion on the bronze propeller of a boat, as shown.
- Leaving Cert Engineering - Question m - 2009
Question m
Explain sacrificial protection as a method of preventing corrosion on the bronze propeller of a boat, as shown.
Worked Solution & Example Answer:Explain sacrificial protection as a method of preventing corrosion on the bronze propeller of a boat, as shown.
- Leaving Cert Engineering - Question m - 2009
Step 1
Explain the issue of corrosion
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Answer
Sea water is highly corrosive and can attack metal components like the bronze propeller of a boat. This corrosion leads to deterioration, making it expensive to replace parts like the propeller.
Step 2
Describe sacrificial protection
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Answer
To prevent corrosion, a sacrificial anode made of a more reactive metal such as zinc, aluminum, or magnesium is attached to the hull of the boat near the propeller. This anode acts as a cathode in an electro-chemical reaction.
Step 3
Explain the electro-chemical action
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Answer
In this process, the anode corrodes instead of the bronze propeller. As the more reactive metal oxidizes, it 'sacrifices' itself, providing protection to the propeller which serves as the cathode. The anode must be replaced periodically as it gets consumed.
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