Surface Treatment
The surface of rare-earth permanent magnets is usually corroded by humidity, acid, alkaline solutions and harmful gases. So surface treatment has to be done to protect the magnets.
| Surface | Method | Thickness (µm) | Colour |
|---|---|---|---|
| Ni | Electroplate | ≥10 | Silver semi-bright |
| Zn | Electroplate | ≥10 | Silver semi-bright |
| Ni+Sn | Electroplate | Ni≥5 Sn≥10 |
Silver semi-bright |
| Aluminum Chromate | Ion-deposition | ≥5 | Yellow semi-bright |
| Resin Coatings | Spray Painting Electrophoresis |
≥20 | black |
