Color coated board four-in-one defense system

Color coated steel plate anti-corrosion is not only two aspects of coating and plating, but there is a whole set of defense system. The anti-corrosion of color coated steel plate is a four-in-one defense system of plating, pretreatment layer, primer and topcoat.

1. Plating plays the role of sacrificial anti-corrosion: it is to extend the service life of steel plate by continuously consuming its own plating. Of course the type, quality and thickness of the plating is the key factor of the length of the consumption of the plating.

2. pretreatment layer: this is a very critical part of the color chart steel plate corrosion, this part is easy to be ignored, pretreatment layer is also called passivation layer, is in the color coating before, using phosphate or chromate and other passivation solution to the substrate passivation treatment. On the one hand, it plays the role of increasing the adhesion of the coating, and on the other hand, it plays the role of anti-corrosion. Some research shows that in the neutral salt spray resistance test of galvanized color steel plate, the contribution of the quality of the pretreatment layer reaches more than 60%.

3. Primer: primer plays the role of increasing the adhesion of the coating on the one hand, and after the paint film is permeable to water, it prevents the layer from blistering and falling off. On the other hand, because the primer contains chromate and other slow-release pigments, it can make the anodic passivation and improve the corrosion resistance of the layer.

4. Topcoat: In addition to aesthetics, the topcoat mainly plays a role in shading the sunlight and preventing UV damage to the coating. After the topcoat reaches a certain thickness, it can reduce the generation of microporosity, which in turn plays a role in shielding the corrosive medium from penetration, reducing the water permeability and oxygen permeability of the coating and preventing corrosion of the coating. Different coatings have different degrees of UV resistance and denseness, and for the same species of coating, the thickness of the paint film is the key factor affecting corrosion.