Unit 2- Class 1- CORROSION (Definition)

Welcome back friends today we will start with a new unit , that is corrosion.At first lets look at its definition.


Definition:
Corrosion is defined as “the destruction or deterioration and consequent loss of metals or alloys through chemical or electrochemical attack by the surrounding environment”.

In simple corrosion and metal extraction can be regarded as

                            Metal -------------> Metal ore



The primary factors that initiate corrosion on metals are atmospheric air, water and also conducting surface of the metal.
Egs: Rusting of iron, green scales are formed on copper vessels

Corrosion of metal occurs either by direct chemical attacks or by electrochemical attack on the metal by the corrosive environment.
If the corrosion takes place due to direct chemical attack (in the absence of moisture ) that type of corrosion is known as dry corrosion.
If the corrosion of metal takes place due to electrochemical attack in presence of moisture or a conducting medium such corrosion is known as wet corrosion or electrochemical corrosion.


let us discuss about dry corrosion and electrochemical corrosion in next post