Cathodic electrophoretic coating During electrophoretic coating, the workpiece is the cathode, the metal surface is not dissolved, and the amine group in the resin has a corrosion inhibition effect. Therefore, the anti-corrosion ability of the cathodic electrophoretic coating is much better than that of the anodic electrophoretic coating . Even without the addition of anti-rust pigments, it still has good salt spray resistance. After phosphating treatment , the electrophoretic paint has a salt spray resistance of 800~1200h, and the high throwing power of the cathodic electrophoretic paint can meet the protection requirements of the automobile body for 10 years without perforation corrosion, so it is widely use.
The development of electrophoretic coatings from anodic electrophoretic coatings to cathodic electrophoretic coatings also eliminates the influence of filiform corrosion and scar corrosion on the appearance of coatings that often occur in anodic electrophoretic coatings; the good flatness of cathodic electrophoretic coatings gives coatings High vividness. The flattening rate of the new generation cathodic electrophoretic coating reaches 83%, and the coating roughness R a is below 0.2 μm.
The introduction of thick-film cathodic electrophoretic coatings (coating film thickness up to 35 μm) can save secondary slurry and simplify the coating process; at the same time, it can improve the corrosion resistance of edges. The salt spray resistance of thick film cathodic electrophoretic coating can reach 1000~1200h.
Compared with anodic electrophoretic coatings, cathodic electrophoretic coatings have higher prices, large equipment investment, and stricter process management requirements. Therefore, the cathodic electrophoretic coating requires good long-term service stability to prevent the tank liquid from deteriorating and being scrapped and causing losses; it must have high throwing power so that the inner cavity and gaps of the car body can be evenly coated with a coating film to achieve The overall protection requirements of the product; the coating film must have high corrosion resistance, so that the high-input, high-tech process equipment can reflect the actual value.
