How to prevent rusting

How to prevent it

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  • Created on: 05-06-09 20:43
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How to prevent rusting
Since rusting costs so much money steps have to be taken to prevent it
happening. There are two main ways of protecting iron and steel from
corrosion. The first method uses a physical barrier to keep out air and
water. The second method called sacrificial protection, involves
attaching a more reactive metal to the iron. Each off the methods has
advantages and disadvantages which make it useful in different
circumstances.
Protection by a physical barrier
For iron or steel to rust oxygen and water must be present. The simplest
way of stopping rusting therefore is to prevent oxygen and metal
getting at the metal. This can be done in several ways:
Paint is cheap and easily applied. Painting is used to protect many
everyday objects like cars bikes bridges etc.
Oil and grease are good flexible coatings which are suitable to
prevent the corrosion of tools and machinery
Plastic coatings are more expensive but they are strong and more
long lasting. Wire netting is often coated with plastic to stop it
corroding
Tin plating is used to make the sheet metal for `tin' cans. These are
suitable for food containers as the tin coating is strong
non-poisonous and prevents corrosion
Electroplating uses electricity to put a thin coating of an expensive
metal onto iron. Metals like chromium and nickel can be used for
electroplating. These metals form a hard, shiny, protective coating.
Cutlery and taps are frequently electroplated
The main disadvantage of using a physical barrier to prevent
rusting is that the coating has to be maintained. If the coating
becomes scratched or broken then air and water will get in to the
iron and it will rust.

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Sacrificial protection:
Railway lines cannot be painted or covered in any other material as
the coating would wear off. A different method of coating has to
be used where coating the metal would be impossible or difficult.
It is discovered that attaching a more reactive metal will stop it
from rusting. Railway lines have bags of magnesium attached to
them. You can also attach zinc.…read more

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