Galvanisation
The coating of iron or steel with a layer of zinc to protect it from corrosion.
Unit
μm
In depth
Zinc protects in two ways: it forms a physical barrier, and being more reactive it corrodes sacrificially even where the coating is scratched. This continued protection at breaks in the coating is what distinguishes galvanising from painting or tin plating.
Examples in the real world
Galvanised roofing sheets, crash barriers and nails, applied by hot dipping in molten zinc.