Question

What is done to prevent corrosion of metals?

Answer 1

Hint:For corrosion to occur, three things are required, namely, an electrolyte, a metal surface and an electron acceptor. If any one of these necessary conditions is removed, corrosion can be prevented.

Complete answer:
Corrosion can be prevented by the following methods.
Applying a protective coating over the metal surface:
Applying a paint coating is a cost-effective way to prevent corrosion. The paint coating act as a barrier between the metal surface and atmospheric moisture to avoid its contact and prevent corrosion. Another alternative is to apply a powder coating. In this method, a dry powder is applied over the clean metal surface thereby avoiding its contact with the surrounding oxygen.
Controlling the environment around the metal surface:
Corrosion is caused by the electrochemical reaction between the metal and gases in the surroundings. By taking necessary measures to control the surrounding environment, the reactions can be minimized. For instance, an iron substance should be kept in a dry environment.
By Sacrificial Coatings:
It is the coating of the metal surface with another metal which oxidizes before the other metal hence avoiding its corrosion. It can be either cathodic protection or anodic protection.

Note:
Cathodic Protection:
The most common example of cathodic protection is galvanization which involves the coating of the surface of iron or its alloys with zinc. Zinc is a more active metal than iron and when in contact with oxygen it corrodes before iron thus preventing its corrosion. .
Anodic Protection:
Anodic protection involves the coating of the iron or its alloy with a less active metal, like tin. The protective layer will not corrode, and thus the surface will be protected as long as the coating is in place.