Metal pretreatment is a chemical process used to clean and prepare metal surfaces before painting, powder coating, electroplating, or other finishing operations. The goal is to improve coating adhesion, corrosion resistance, and overall product life.
* Metal Pretreatment Is Important
- Removes oil, grease, dirt, and contaminants.
- Removes rust and oxide layers.
- Creates a uniform surface for coating.
- Improves paint and powder coating adhesion.
- Increases corrosion resistance.
- Reduces coating failures and rework.
* Typical 7-Tank Pretreatment Process
1. Degreasing Tank
Removes oil, grease, and dirt.
Chemicals: Alkaline cleaners, degreasers.
2. Water Rinse
Washes off residual degreaser.
3. Derusting/Pickling Tank
Removes rust, scale, and oxidation.
Chemicals: Acid-based rust removers.
4. Water Rinse
Removes acid residues.
5. Phosphating Tank
Creates a phosphate coating on the metal surface.
Chemicals: Iron phosphate or zinc phosphate.
Improves paint adhesion and corrosion resistance.
6. Water Rinse
Removes excess phosphate chemicals.
7. Passivation/Final Rinse Tank
Enhances corrosion protection.
Chemicals: Passivation solutions or sealers.
