The electro-coat system applies a Direct Current (DC) charge to an unfinished metal part immersed in a bath of paint particles containing an opposing charge. The paint particles are drawn to the metal part and paint is evenly deposited forming a continuous film over the entire surface, until the coating reaches the desired thickness. At a predetermined thickness, this film build insulates the part, attraction stops, and the process is complete.
Depending on the polarity of the charge, electrocoating is classified as either anodic or cathodic.
In anodic electrocoating, the part to be coated is considered the anode. With a positive electric charge, this part will attract negatively charged paint particles from the paint bath. During the anodic process, small amounts of metal ions migrate into the paint film. This metal-migration can limit the coating performance properties. The main use for anodic products is interior or moderately exterior environments. Anodic coatings are economical systems that offer excellent color and gloss control.
In cathodic electrocoating, the part to be coated is considered the cathode. With a negative electric charge, this part will attract positively charged paint particles from the paint bath. With this reversal of polarities, the amount of iron entering the cured paint film is greatly reduced which improves the cathodic properties. Cathodic coatings are high-performance coatings with excellent corrosion resistance that can be formulated for exterior durability.