Originally designed and developed for and by the automotive industry, the surface treatment of metals known as “E-Coat” or “Cataphoresis” in Europe, involves the electrochemical deposition of a sheet or film of organic paint onto a metal part.
The “E-Coat” process involves immersing the part to be painted in a bath of water-soluble paint, placing the part at the cathode (hence the name cataphoresis), and causing the paint particles in solution in the bath to migrate by means of an electric current at a certain voltage, from the anode to the cathode. The painted parts are drained and the paint is cured (polymerized).
The advantages
- Uniform paint thickness over the entire surface;
- Superior corrosion protection;
- Coverage of sharp edges;
- Coverage of confined areas (e.g., inside a pipe).
The stages
| Stage 1 | Stage 2 | Stage 3 |
|---|---|---|
| Pre-degreasing | Main degreasing | Rinsing |
| Stage 4 | Stage 5 | Stage 6 |
| Acid pickling | Neutralization | Rinsing |
| Stage 7 | Stage 8 | Stage 9 |
| Conditioning | Zinc phosphate | Rinsing |
| Stage 10 | Stage 11 | Stage 12 – E-Coat |
| Sealer | Rinsing | E-Coat (cataphoresis) |
| Stages 13 & 14 | Stage 15 | Stage 16 |
| Permeate | Rinsing | Draining |
Oven – Curing (crosslinking/polymerization)
The E-Coat process can accommodate parts weighing up to 450 pounds, 350 square feet, and/or 10ˈx5ˈx5ˈ (L x W x H).
Parts painted with E-Coat can be used as it is or receive a powder paint layer in the desired color according to customer requirements.
There is no specific deadline for applying powder paint after the E-Coat process has been completed. It is just important to ensure that the parts are not exposed to UV light. In general, parts will be painted after E-Coat within 48 hours, and at worst within 5 business days.
