how does a coatong of zinc on galvanized iron protect it from corrosion?

Answer 1

Mild steel is very susceptable to oxidation or rust. Galvanizing the metal prevents the oxidation from occuring, So it is really a sealing or protection of the mild steel that protects it from corrosion.

Answer 2

All three above answers are correct. As long as there's even a little bit of zinc in contact with the iron, the zinc will corrode and the iron will not. Even a chunk of zinc bolted to the iron will protect it. This is how ships' steel hulls and oil platforms are protected. As the zinc oxidises, the iron or steel acquires a negative charge which protects it from oxidation. So galvanising provides better protection than paint. Paint only protects the surface it covers. Where it flakes away, the surface rusts. Another similar way to protect a surface underwater, like a ship's hull or oil platform, is to connect the negative terminal of a DC generator to it, place an inert anode, like a carbon rod, a few metres away, and generate about a kilowatt of electricity to keep the hull negative.

Answer 3

A simple answer is that, because zinc is higher up in the reactivity series than iron, it is oxidised instead of the iron. While there is zinc in contact with the surface of the iron, the iron cannot rust.

Answer 4

zinc oxidises more easily than iron, so when exposed to air, the coating of zinc, being more reactive, would corrode in place of iron -- in which zinc is also known as sacrificial metal -- , therefore protecting the galvanized iron from being corroded. hope this helps :)

Answer 5

with the aid of fact interior the galvanizing technique, there's a small layer of metallic that has surely bonded with the zinc. The white stuff is only extra. in case you have been to purchase a sheet of "satin coat" metallic, it could have this extra wiped off, waiting for portray (thats what they use for motor vehicle bodies).