What is sacrificial protection in corrosion control?

• A. The deliberate sacrifice of one metal to protect another.
• B. Coating with paint
• C. Polishing to remove oxide layers
• D. Heat treatment to increase hardness

Answer: (A)

Sacrificial protection is a corrosion control method where a more electrochemically active metal is deliberately used to corrode in place of the metal we want to protect. When the two metals are in electrical contact in an electrolyte, a galvanic cell forms and the more active metal becomes the anode, corroding instead of the protected metal. This is why zinc is often used to protect steel—either as a galvanizing coating or as sacrificial anodes on structures like ships or pipelines. The sacrificial metal will gradually be consumed and must be replaced to continue protection.

Coating with paint provides a physical barrier to moisture and electrolytes, but it’s not sacrificial protection. Polishing to remove oxide layers isn’t a protective strategy for long-term corrosion control, and heat treatment to increase hardness relates to mechanical properties, not corrosion protection.