Steel that is coated with a zinc layer to protect it from corrosion.
Galvanized steel is remarkably corrosion-resistant, because even if a scratch appears on its surface, the zinc coating will nevertheless protect the steel beneath.
A generally hard, strong, durable, malleable alloy of iron and carbon, usually containing between 0.2 and 1.5 percent carbon, often with other constituents such as manganese,
chromium, nickel, molybdenum, copper, tungsten, cobalt, or silicon, depending on the desired alloy properties, and widely used as a structural material. Zinc coatings prevent corrosion of the protected metal by forming a barrier, and by acting as a sacrificial anode if this barrier is damaged. When exposed to the atmosphere, zinc reacts with oxygen to form zinc oxide,
which further reacts with water molecules in the air to form zinc hydroxide. Finally zinc hyroxide reacts with carbon dioxide in the atmosphere to yield a thin, impermeable, tenacious and quite insoluble dull gray layer of zinc carbonate which
adheres extremely well to the underlying zinc, so protecting it from further corrosion, in a way similar to the protection afforded to aluminium and stainless steels by their oxide layers. Zinc, which has been used to hot-dip-galvanize steel for 250 years, provides 50 to 75 years of corrosion protection in many environments. Empirical data collected about hot-dip galvanized (HDG) steel field performance from 1940 to 1980 in environments ranging from industrial to marine to suburban indicates that zinc can prevent base steel corrosion more than other surface treatments.
Because of zinc’s long-lasting protection, projects require no maintenance and therefore no maintenance costs.