How does zinc protect steel from rusting?

Answer 1

great chemistry question. rusting is a redox reaction (transfer of electrons). since zinc has a higher activity for reating than does the iron, when together, zinc and iron, even though both metals would like to oxidize (lose electrons, become the metallic part of an ionic compound, or rust), only the metal with the higher activity level can. so, zinc "rusts", meaning the zinc will become oxidized (zinc atoms become zinc ions and for into zinc-anion compounds, leaving the iron to remain intact, with those great iron properties such as strength (your boat doesn't bend, your bridge doesn't collapse). redox is quite neat, rusting forms iron into Iron (III) oxide, Fe2O3, and has wonderful properties of its own, just not so good in the strength department.

Answer 2

Zinc is used to protect steel from rusting because it is more reactive than than iron. When galvanized (zinc-coated) stell is exposed to oxidizing conditions a small electric current forms which in essence protects the steel from corrosion as the zinc corrodes instead.

Answer 3

The metal is most commonly used as an anti-corrosion agent. Galvanization, which is the coating of iron or steel to protect the metals against corrosion, is the most familiar form of using zinc in this way. In 2009 in the United States, 55% or 893 thousand tonnes of the zinc metal was used for galvanization.

Zinc is more reactive than iron or steel and thus will attract almost all local oxidation until it completely corrodes away. A protective surface layer of oxide and carbonate (Zn5(OH)6(CO3)2) forms as the zinc corrodes. This protection lasts even after the zinc layer is scratched but degrades through time as the zinc corrodes away.

Source: Wikipedia-en

Answer 4

It has to do with the "nobility" of the two metals according to the galvanic series. If you put two metals in an electrolyte, like water, the less-noble metal will be attacked. The only metal less noble than zinc is magnesium, which is used as an anode only in water heaters because it's more expensive than zinc. Zinc isn't used in a water heater because drinking too much zinc is bad for you.

Answer 5

The zinc "rusts" (oxidizes) first ... but zinc oxide isn't the soft porous material that iron oxide is - thus the coating stays intact.

Answer 6

It is basically sacrificial corrosion,

Since zinc is more reactive than iron, an acid would react with it rather than the iron

Answer 7

It basically galvanises the steel

Answer 8

Because Zinc is less reactive.