Corrosion control

1. CORROSION CONTROL
Presented By:-
Reethu K
Karthik
Shashank
Narendra
Shanon
Zabin

2. What do you mean by
Corrosion Control ?
• Protecting the surface of the metal so that corrosion reaction donot
take place at the surface is known as corrosion control.

3. Methods of Corrosion Control
i. Metal Coating
ii.Anodizing
iii.Cathodic Protection

4. i.Metal Coating
• Deposition of a protective metal over the surface of a base metal is
called metalic coating

5. Types of Metal Coating
 Anodic Coating:-
Anodic coatings are produced
by coating a base metal with
more active metals which are
anodic to the base metal.
Eg: Iron is coated with anodic
and active metals like Zn,Mg
and Al.

6. Advantages:-
 if the coating is ruptured, the base metal does not undergo
corrosion.
 No possibility of fading
 Excellent corrosion resistance
 No risk of adhesion failure

7. Galvanisation:-
 It is a process of coating a
base metal surface with Zinc
metal.
• Galvanisation is carried out by
hot dipping method

8. Uses:-
• They are used to protect roofing sheets,water pipes,barbed
wires,buckets etc
• Provides the required high-quality,long term corrosion protection to
stell.

9. ii.Anodizing
 It is an electrochemical process that develops an
aluminium oxide coat on the surface of the part or product.
 This protects the product from wear and tear while improving the
aesthetics.
 Anodized coating is generally produced on non ferrous metals like
Al, Zn,Mg and their alloys by anodic oxidation process.

10. Anodization Of
Aluminium:-
 The process of anodising
aluminium involves
submerging the metal in an
acid electrolyte bath and
passing an electrical current
through the solution.
 The bath has a cathode
attached to it and the
aluminium acts as the anode.

11. Advantages:-
 Durability and harder than normal aluminium
 Color stability
 Ease of maintenance
 Aesthetics
 Healthy and safety
Applications:-
 Food preparation equipment
 Motor vehicle components
 Appliances
 Sporting goods and boats
 Commercial and residential building products
 Jewelry and artwork

12. iii.Cathodic Protection
 It is the method of protecting a
metal or alloy from corrosion
by converting it completely into
cathodic and no part of it is
allowed to act as anode.

13. Two methods of cathodic protection
 Sacrificial anode
method:-
 The protected metal
structure is converted into cathode
by connecting it to a more active
metal.
 This active metal acts as
auxillary anode like Zn,Mg and Al
are common auxillary anode.
 More reactive anode
undergo corrosion to protect metal
structure.
 Eg: Mg blocks are
connected to burried steelpipe

14. Advantages:-
 Donot require external power supply
 Easy to install
 Low cost
 Minimum maintanence cost
Disadvantages:-
 Anode current is uncontrolled
 Fuel consumption is increased
 Frequently replacement is necessary
 Replacement is usually necessary before scheduled time

15.  Impressed current
method:-
 In this method ,by applying a
direct current larger than
corrosion current .
 The metal structure being
cathode does not undergo
corrosion and Anode being
inert remains unaffected.
 Graphite is widely used as
inert anode.

16. Advantages:-
 Low installation cost
 One installation can protect large area of a metal
 Longer life anodes
 Higher current system
 Ease monitoring and control
 Flexibility
Disadvantages:-
 Increased maintenance
 Higher operating cost
 May cause interference on other structures

17. THANK
YOU