Previous Year Question

Correct answer: C — Zinc

What galvanizing does

Galvanizing is the process of applying a protective zinc coating to iron or steel. In hot-dip galvanizing, suitably cleaned steel is immersed in molten zinc. The resulting coating includes bonded iron–zinc layers and an outer zinc-rich surface.

The coating protects the base metal in two related ways. First, it forms a physical barrier that reduces contact between steel and the surrounding moisture and oxygen. Second, zinc is electrochemically more active than iron and can corrode preferentially when both are exposed to an electrolyte. This is called sacrificial protection.

Sacrificial action explains why a small scratch need not immediately cause the exposed steel to rust as rapidly as unprotected steel. Protection is not unlimited: it depends on the surrounding coating remaining available and the exposure conditions. As the zinc is consumed, its protection eventually diminishes.

Galvanized steel is widely used for transmission-tower components, line hardware and conventional ACSR steel strands because these parts are exposed to the weather. The defining coating metal in the process is zinc.