Definition - What does Cathodic Coating mean?
Cathodic coatings involve coating metal, which is cathodic with respect to the substrate in an electrochemical cell.
The purpose of this type of coating is to protect the substrate from corrosion. In corrosive environments accelerated corrosion of the substrate occurs if cathodic coating fails to protect the substrate.
Cathodic coatings are also known as electrophoretic deposition (EPD), e-coating, electro coating, cathodic electro deposition, electrophoretic coating, anodic electro deposition and electrophoretic painting.
Corrosionpedia explains Cathodic Coating
The cathodic coating process involves submerging a part into a container which holds the coating bath or solution and applying direct current through the cathodic electro deposition bath using electrodes. Typically voltages of 25-400 volts are used in electro coating. The object to be coated is one of the electrodes (cathode), and a set of counter electrodes are used to complete the circuit.
After deposition the object is rinsed to remove the undeposited bath. The coating is finally subjected to a curing process in which reduction of porosity and cross linking of coating material takes place. This makes the surface smooth and continuous.
Cathodic coatings are used in following:
- Hybrid electric vehicles
- Portable electronic devices
- Medical devices
- Space and defense-related devices