prevention of rusting of iron by using cathodic protection method

Dear student!

Cathodic protection is the technique to prevent corrosion without changing the color or luster of the metals. The process depends on the principle to alter the electrode potential of the metallic structure so that they can enter in immunity region where the metal is found in its stable state so that corrosion reaction could not be possible.

The best method of cathode protection which is used is "impressed current" in which the electric current is applied to the metal surface by the use of a DC circuit in which the -ve and +ve terminals are attached to the metal and an auxiliary anode respectively.In case of protection of iron, the auxilliary metal; can be any metal which is more electropositive  and reactive than iron , for example zinc. The flow of electric current charges the structure and changes the electrode potential in negative direction The process continues till the metal reaches to its immunity region and the current flows from anode to cathode. Thus the process protects metals from corrosion.

 

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In this method iron is made as the cathode and suitable reactive metal is used as the anode.The metal is coated with suitable antirust solution eg-alkaline phosphate

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