Cathodic dip coating (CDC)

Cathodic dip coating (CDC) – also known as “cataphorisis” – is a proven electrochemical coating process and is used in applications such as the surface coating of car bodies. In the coating process the substrate or item to be painted is immersed in a watery dip coating and used as a cathode. When a direct current of approximately 3,000 amperes and 220 to 320 volts is applied the electrochemical process of CDC separation (Link) occurs. A direct current field is generated between the object that is to be coated and the anode. This enables water soluble colloidal binding agent particles (micelles) to be deposited on the surface of the coating object used as a cathode. The result is a firm, closed and adhesive coating film on the substrate. This is then annealed or cross-linked in a furnace. Depending on the geometry of the parts, a coat with a thickness of between 10 and 40 µm is deposited on the object in the coating process. The precise thickness of the coat can be precisely controlled via the amount of current.