Before applying protective coatings to steel tanks and other metallic surfaces, the surface must be properly prepared to remove corrosion and other contaminants. If a surface is not properly rid of contaminants prior to a coating application, coatings can fail prematurely, resulting in costly and serious consequences, such as unwanted downtime, increased maintenance, and safety concerns.
MORE THAN MEETS THE EYE
Thorough surface preparation requires more than just removal of visible rust. Sometimes a surface appears clean and ready for coating, but microscopic contaminants are present in surface depressions, as shown in Figure 1. These microscopic particles attract moisture, which adheres to the contaminants, initiating chemical reactions and accelerating corrosion. In addition, the contaminants can prevent coatings from properly adhering to the surface, leaving gaps between the surface and coating that allow additional moisture intrusion and accelerated coating failure.