How to protect Metal from Corrosion
There are four basic methods to Protect Metal from Corrosion:
- Materials resistant to Corrosion
-
Protective coatings
-
Cathodic protection
- Corrosion Inhibitors - Modify the operating environment.
In most cases, effective corrosion control is obtained by combining two or more of these methods.
Corrosion control should be considered at the design stage of a given facility or system.
The methods selected must be appropriate for the
materials used, for the configurations, and for the types and forms of corrosion
which must be controlled.
There are no materials that are immune to corrosion in all environments.
Materials must be matched to the environment that they will encounter in
service.
Protective coatings are the most widely used corrosion control technique. Essentially, protective coatings protect metal from corrosion by separating the surfaces that are susceptible to corrosion from the factors in the environment which cause corrosion to occur.
Cathodic protection protect metal from corrosion by interfering with the natural action of the electrochemical cells that are responsible for corrosion. Cathodic protection can be effectively applied to control corrosion of surfaces that are immersed in water or exposed to soil.
Corrosion Inhibitor protect metal from corrosion by one or more of these mechanisms:
1. By adsorption as a thin film on the surface of a corroding material
2. By inducing formation of a thick corrosion product
3. By forming a passive film on the metal surface
4. By changing characteristics of the environment either by producing protective precipitates or by removing or inactivating an aggressive constituen
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