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Galvanizing is a process used to protect steel by applying a sacrificial coating? Which metal is used in galvanizing?
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Correct Answer: A. Zinc.
To provide a sacrificial coating the coating metal must be more reactive than the base metal being protected. Thus gold and copper are not applicable as they are both less reactive than iron and can only provide a passive coating.
Aluminum and zinc are more reactive than iron. Aluminum and zinc both form protective oxide layers that will stop corrosion of the iron, but aluminum is too reactive to be used in exposed weathering conditions. It is zinc that has just the right degree of reactivity that allows it to both protect the iron and not be corroded away, providing a strong and long lasting sacrificial coating.
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