Organic Coatings Protection Mechanism

Organic coatings may provide corrosion prevention by controlling one or multiple rate controlling steps in corrosion reaction. These may include:

• Establish a barrier for water transportation;
• Establish a barrier for oxygen or other gaseous corrodants diffusion;
• An effective electrical resistance barrier to interfere electron transferring in electrochemical reactions;
• Metal surface passivation.

The effectiveness of coatings is highly relying on their service environment. Therefore, the corrosion prevention mechanism of particular coating type is the key criteria for the success of coating application. For example, for structure immersed in sea water, electrolyte resistance is the major consideration in coatings selection. For on-shore pipeline service, oxygen diffusion, cathodic disbonding and soil stress resistance are probably more critical.

• Reading and digest from Corrosion Control Through Organic Coatings.