Quick Revision- Corrosion and its prevention

Quick revision

Topic:  Corrosion and its prevention

 

Definition:  It is the process in which metals are slowly eaten up by the action of air moisture or chemicals. For example rusting is a form of corrosion in which iron is eaten up by the action of air and moisture and a reddish brown coating of iron oxide is formed as shown in the following chemical reaction.

 

Ill effects of corrosion:

Definitely there are many harmful effects of corrosion. Some of them are listed below.

  • Loss of efficiency
  • Contamination of product
  • Damage of metallic equipment’s
  • Inability to use metallic materials
  • Loss of valuable materials such as blockage of pipes, mechanical damage of underground water pipes
  • Accidents due to mechanical loss of metallic bridges, cars, aircrafts etc.
  • Causes pollution due to escaping products from corrosion
  • Depletion of natural resource ( Metals)

 

 

Methods of prevention of corrosion:

Coating and Painting ·         Iron surface is often painted with the coatings of varnish or paint to isolate it from the environment. Window grills, bodies of automobiles, iron bridges and rails are painted regularly to protect them from rusting.

 

Applying a layer of grease
  • Grease or a layer of oil is also applied to iron surfaces, primarily on machines and industry tools. This serves dual purpose of a lubricant reducing friction as well as rust prevention.

 

Galvanisation
  • It is a process of depositing a thin layer of a non-reactive metal like zinc on the surface of iron. This metallic layer prevents the iron to come in contact with air and moisture. Buckets, drums, roofs, pipes etc. are galvanized to prevent rusting.